[PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support

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* [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support
@ 2014-03-17 22:22 Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 01/13] x86, vdso: Make vsyscall_gtod_data handling x86 generic Stefani Seibold
                   ` (12 more replies)
  0 siblings, 13 replies; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch add the functions vdso_gettimeofday(), vdso_clock_gettime()
and vdso_time() to the x86 32 bit VDSO.

The reason to do this was to get a fast reliable time stamp. Many developers
uses TSC to get a fast time stamp, without knowing the pitfalls. VDSO
time functions a fast and a reliable way, because the kernel knows the
best time source and the P- and C-state of the CPU.

The helper library to use the VDSO functions can be download at
http://http://seibold.net/vdso.c
The libary is very small, only 228 lines of code. Compile it with
gcc -Wall -O3 -fpic vdso.c -lrt -shared -o libvdso.so
and use it with LD_PRELOAD=<path>/libvdso.so

There is also a patch http://seibold.net/glibc.patch for glibc 2.19 which also
works for glibc 2.18.  This patch must be integrated into glibc.

Some linux 32 bit kernel benchmark results (all measurements are in nano
seconds):

Intel(R) Celeron(TM) CPU 400MHz

Average time kernel call:
 gettimeofday(): 1039
 clock_gettime(): 1578
 time(): 526
Average time VDSO call:
 gettimeofday(): 378
 clock_gettime(): 303
 time(): 60

Celeron(R) Dual-Core CPU T3100 1.90GHz

Average time kernel call:
 gettimeofday(): 209
 clock_gettime(): 406
 time(): 135
Average time VDSO call:
 gettimeofday(): 51
 clock_gettime(): 43
 time(): 10

So you can see a performance increase between 4 and 13, depending on the
CPU and the function.

The IA32 Emulation uses the whole 4 GB address space, so there is no
fixed address available.

The VDSO for a 32 bit application has now three pages:

^ Higher Address
|
+----------------------------------------+
+ VDSO page (includes code) ro+x         +
+----------------------------------------+
+ VVAR page (export kernel variables) ro +
+----------------------------------------+
+ HPET page (mapped registers) ro 
+----------------------------------------+
|
^ Lower Address

The VDSO page for a 32 bit resided still on 0xffffe000, the the VVAR and
HPET page are mapped before.

In the non compat mode the VMA of the VDSO is now 3 pages for a 32 bit kernel.
So this decrease the available logical address room by 2 pages.

The patch is against tip x86/vdso (1f2cbcf648962cdcf511d234cb39745baa9f5d07)

Changelog:
25.11.2012 - first release and proof of concept for linux 3.4
11.12.2012 - Port to linux 3.7 and code cleanup
12.12.2012 - fixes suggested by Andy Lutomirski
           - fixes suggested by John Stultz
           - use call VDSO32_vsyscall instead of int 80
           - code cleanup
17.12.2012 - support for IA32_EMULATION, this includes
             - code cleanup
             - include cleanup to fix compile warnings and errors
             - move out seqcount from seqlock, enable use in VDSO
             - map FIXMAP and HPET into the 32 bit address space
18.12.2012 - split into separate patches
30.01.2014 - revamp the code
             - code clean up
             - VDSO layout changed
             - no fixed addresses
             - port to 3.14
01.02.2014 - code cleanup
02.02.2014 - code cleanup
             - split into more patches
             - use HPET_COUNTER instead of hard coded value
             - fix changelog to the right year ;-)
02.02.2014 - reverse the mapping, this make the new VDSO 32 bit support
             full compatible.
03.02.2014 - code cleanup
             - fix comment
             - fix ABI break in vdso32.lds.S
04.02.2014 - revamp IA32 emulation support
             - introduce VVAR macro
             - rearranged vsyscall_gtod_data struture for IA32 emulation support
             - code cleanup
05.02.2014 - revamp IA32 emulation support
             - replace seqcount_t by an unsigned, to make the vsyscall_gtod_data
               structure independed of kernel config and functions.
08.02.2014 - revamp IA32 emulation support
             - replace all internal structures by fix size elements
10.02.2014 - code cleanup
             - add commets
             - revamp inline assembly
12.02.2014 - add conditional fixmap of vvar and hpet pages for 32 bit kernel
14.02.2014 - fix CONFIG_PARAVIRT_CLOCK, which is not supported in 32 bit VDSO
15.02.2014 - fix tsc
             code cleanup
             tested make ARCH=i386 allyesconfig and make allyesconfig
16.02.2014 - code cleanup
             - fix all C=1 warnings, also some one not introduced by this patch
             - hack to fix C=1 32 bit VDSO spinlock for a 64 bit kernel
             - fix VDSO Makefile for newer gcc
             tested for gcc 4.3.4 and 4.8.1
             tested ARCH=i386 allyesconfig, defconfig and allmodconfig
             tested X86_64 allyesconfig, defconfig and allmodconfig
17.02.2014 - In case of a 32 bit VDSO for a 64 bit kernel fake a 32 bit kernel
             configuration.
19.02.2014 - Add missing #undef and #define to fake proper 32 bit kernel config
             Add a missing #ifdef CONFIG_HPET_TIMER
             tested again ARCH=i386 allyesconfig, defconfig and allmodconfig
             tested again ARCH=X86_64 allyesconfig, defconfig and allmodconfig
02.03.2014 - Add fixes suggested by Andy Lutomirski
             - Patch alternatives in the 32 bit VDSO
	     - Use the default ABI for the 32 bit VDSO
	     - Inline the CLOCK MONOTONIC VDSO code
	     - Zero pad the VVAR page
	     - fix "patch alternatives" compile for 32 bit kernel
03.03.2014 - Add glibc.patch http://seibold.net/glibc.patch
             Add reviewed-by tags
17.03.2014 - Rebase on tip x86/vdso 1f2cbcf648962cdcf511d234cb39745baa9f5d07
             remove fixmap and compat mode dependencies

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v23 01/13] x86, vdso: Make vsyscall_gtod_data handling x86 generic
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:27   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 02/13] mm: Add new func _install_special_mapping() to mmap.c Stefani Seibold
                   ` (11 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch move the vsyscall_gtod_data handling out of vsyscall_64.c
into an additonal file vsyscall_gtod.c to make the functionality
available for x86 32 bit kernel.

It also adds a new vsyscall_32.c which setup the VVAR page.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/Kconfig                   |  4 +--
 arch/x86/include/asm/clocksource.h |  4 ---
 arch/x86/include/asm/vvar.h        | 12 ++++++--
 arch/x86/kernel/Makefile           |  2 +-
 arch/x86/kernel/hpet.c             |  2 --
 arch/x86/kernel/tsc.c              |  2 --
 arch/x86/kernel/vmlinux.lds.S      |  3 --
 arch/x86/kernel/vsyscall_64.c      | 45 -----------------------------
 arch/x86/kernel/vsyscall_gtod.c    | 59 ++++++++++++++++++++++++++++++++++++++
 arch/x86/tools/relocs.c            |  2 +-
 10 files changed, 72 insertions(+), 63 deletions(-)
 create mode 100644 arch/x86/kernel/vsyscall_gtod.c

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9122f6b..ab3ebc8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -107,9 +107,9 @@ config X86
 	select HAVE_ARCH_SOFT_DIRTY
 	select CLOCKSOURCE_WATCHDOG
 	select GENERIC_CLOCKEVENTS
-	select ARCH_CLOCKSOURCE_DATA if X86_64
+	select ARCH_CLOCKSOURCE_DATA
 	select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
-	select GENERIC_TIME_VSYSCALL if X86_64
+	select GENERIC_TIME_VSYSCALL
 	select KTIME_SCALAR if X86_32
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
diff --git a/arch/x86/include/asm/clocksource.h b/arch/x86/include/asm/clocksource.h
index 16a57f4..eda81dc 100644
--- a/arch/x86/include/asm/clocksource.h
+++ b/arch/x86/include/asm/clocksource.h
@@ -3,8 +3,6 @@
 #ifndef _ASM_X86_CLOCKSOURCE_H
 #define _ASM_X86_CLOCKSOURCE_H
 
-#ifdef CONFIG_X86_64
-
 #define VCLOCK_NONE 0  /* No vDSO clock available.	*/
 #define VCLOCK_TSC  1  /* vDSO should use vread_tsc.	*/
 #define VCLOCK_HPET 2  /* vDSO should use vread_hpet.	*/
@@ -14,6 +12,4 @@ struct arch_clocksource_data {
 	int vclock_mode;
 };
 
-#endif /* CONFIG_X86_64 */
-
 #endif /* _ASM_X86_CLOCKSOURCE_H */
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index d76ac40..0a534ea 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -16,9 +16,6 @@
  * you mess up, the linker will catch it.)
  */
 
-/* Base address of vvars.  This is not ABI. */
-#define VVAR_ADDRESS (-10*1024*1024 - 4096)
-
 #if defined(__VVAR_KERNEL_LDS)
 
 /* The kernel linker script defines its own magic to put vvars in the
@@ -29,6 +26,15 @@
 
 #else
 
+extern char __vvar_page;
+
+/* Base address of vvars.  This is not ABI. */
+#ifdef CONFIG_X86_64
+#define VVAR_ADDRESS (-10*1024*1024 - 4096)
+#else
+#define VVAR_ADDRESS (&__vvar_page)
+#endif
+
 #define DECLARE_VVAR(offset, type, name)				\
 	static type const * const vvaraddr_ ## name =			\
 		(void *)(VVAR_ADDRESS + (offset));
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index cb648c8..f4d9600 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -26,7 +26,7 @@ obj-$(CONFIG_IRQ_WORK)  += irq_work.o
 obj-y			+= probe_roms.o
 obj-$(CONFIG_X86_32)	+= i386_ksyms_32.o
 obj-$(CONFIG_X86_64)	+= sys_x86_64.o x8664_ksyms_64.o
-obj-y			+= syscall_$(BITS).o
+obj-y			+= syscall_$(BITS).o vsyscall_gtod.o
 obj-$(CONFIG_X86_64)	+= vsyscall_64.o
 obj-$(CONFIG_X86_64)	+= vsyscall_emu_64.o
 obj-$(CONFIG_SYSFS)	+= ksysfs.o
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index da85a8e..e4b86ab 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -752,9 +752,7 @@ static struct clocksource clocksource_hpet = {
 	.mask		= HPET_MASK,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= hpet_resume_counter,
-#ifdef CONFIG_X86_64
 	.archdata	= { .vclock_mode = VCLOCK_HPET },
-#endif
 };
 
 static int hpet_clocksource_register(void)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index cfbe99f..227dcfc 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -985,9 +985,7 @@ static struct clocksource clocksource_tsc = {
 	.mask                   = CLOCKSOURCE_MASK(64),
 	.flags                  = CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
-#ifdef CONFIG_X86_64
 	.archdata               = { .vclock_mode = VCLOCK_TSC },
-#endif
 };
 
 void mark_tsc_unstable(char *reason)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index da6b35a..1d4897b 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -147,7 +147,6 @@ SECTIONS
 		_edata = .;
 	} :data
 
-#ifdef CONFIG_X86_64
 
 	. = ALIGN(PAGE_SIZE);
 	__vvar_page = .;
@@ -169,8 +168,6 @@ SECTIONS
 
        . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
 
-#endif /* CONFIG_X86_64 */
-
 	/* Init code and data - will be freed after init */
 	. = ALIGN(PAGE_SIZE);
 	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 1f96f93..9ea2876 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -47,14 +47,12 @@
 #include <asm/segment.h>
 #include <asm/desc.h>
 #include <asm/topology.h>
-#include <asm/vgtod.h>
 #include <asm/traps.h>
 
 #define CREATE_TRACE_POINTS
 #include "vsyscall_trace.h"
 
 DEFINE_VVAR(int, vgetcpu_mode);
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
 
 static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
 
@@ -77,48 +75,6 @@ static int __init vsyscall_setup(char *str)
 }
 early_param("vsyscall", vsyscall_setup);
 
-void update_vsyscall_tz(void)
-{
-	vsyscall_gtod_data.sys_tz = sys_tz;
-}
-
-void update_vsyscall(struct timekeeper *tk)
-{
-	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
-
-	write_seqcount_begin(&vdata->seq);
-
-	/* copy vsyscall data */
-	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;
-	vdata->clock.cycle_last		= tk->clock->cycle_last;
-	vdata->clock.mask		= tk->clock->mask;
-	vdata->clock.mult		= tk->mult;
-	vdata->clock.shift		= tk->shift;
-
-	vdata->wall_time_sec		= tk->xtime_sec;
-	vdata->wall_time_snsec		= tk->xtime_nsec;
-
-	vdata->monotonic_time_sec	= tk->xtime_sec
-					+ tk->wall_to_monotonic.tv_sec;
-	vdata->monotonic_time_snsec	= tk->xtime_nsec
-					+ (tk->wall_to_monotonic.tv_nsec
-						<< tk->shift);
-	while (vdata->monotonic_time_snsec >=
-					(((u64)NSEC_PER_SEC) << tk->shift)) {
-		vdata->monotonic_time_snsec -=
-					((u64)NSEC_PER_SEC) << tk->shift;
-		vdata->monotonic_time_sec++;
-	}
-
-	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;
-	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);
-
-	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,
-							tk->wall_to_monotonic);
-
-	write_seqcount_end(&vdata->seq);
-}
-
 static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
 			      const char *message)
 {
@@ -374,7 +330,6 @@ void __init map_vsyscall(void)
 {
 	extern char __vsyscall_page;
 	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
-	extern char __vvar_page;
 	unsigned long physaddr_vvar_page = __pa_symbol(&__vvar_page);
 
 	__set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_vsyscall,
diff --git a/arch/x86/kernel/vsyscall_gtod.c b/arch/x86/kernel/vsyscall_gtod.c
new file mode 100644
index 0000000..b5a943d
--- /dev/null
+++ b/arch/x86/kernel/vsyscall_gtod.c
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ *  Copyright 2003 Andi Kleen, SuSE Labs.
+ *
+ *  Modified for x86 32 bit architecture by
+ *  Stefani Seibold <stefani@seibold.net>
+ *
+ *  Thanks to hpa@transmeta.com for some useful hint.
+ *  Special thanks to Ingo Molnar for his early experience with
+ *  a different vsyscall implementation for Linux/IA32 and for the name.
+ *
+ */
+
+#include <linux/timekeeper_internal.h>
+#include <asm/vgtod.h>
+
+DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
+
+void update_vsyscall_tz(void)
+{
+	vsyscall_gtod_data.sys_tz = sys_tz;
+}
+
+void update_vsyscall(struct timekeeper *tk)
+{
+	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
+
+	write_seqcount_begin(&vdata->seq);
+
+	/* copy vsyscall data */
+	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;
+	vdata->clock.cycle_last		= tk->clock->cycle_last;
+	vdata->clock.mask		= tk->clock->mask;
+	vdata->clock.mult		= tk->mult;
+	vdata->clock.shift		= tk->shift;
+
+	vdata->wall_time_sec		= tk->xtime_sec;
+	vdata->wall_time_snsec		= tk->xtime_nsec;
+
+	vdata->monotonic_time_sec	= tk->xtime_sec
+					+ tk->wall_to_monotonic.tv_sec;
+	vdata->monotonic_time_snsec	= tk->xtime_nsec
+					+ (tk->wall_to_monotonic.tv_nsec
+						<< tk->shift);
+	while (vdata->monotonic_time_snsec >=
+					(((u64)NSEC_PER_SEC) << tk->shift)) {
+		vdata->monotonic_time_snsec -=
+					((u64)NSEC_PER_SEC) << tk->shift;
+		vdata->monotonic_time_sec++;
+	}
+
+	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;
+	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);
+
+	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,
+							tk->wall_to_monotonic);
+
+	write_seqcount_end(&vdata->seq);
+}
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index cfbdbdb..bbb1d22 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -69,8 +69,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"__per_cpu_load|"
 	"init_per_cpu__.*|"
 	"__end_rodata_hpage_align|"
-	"__vvar_page|"
 #endif
+	"__vvar_page|"
 	"_end)$"
 };
 
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 02/13] mm: Add new func _install_special_mapping() to mmap.c
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 01/13] x86, vdso: Make vsyscall_gtod_data handling x86 generic Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 03/13] x86, vdso: Revamp vclock_gettime.c Stefani Seibold
                   ` (10 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

The _install_special_mapping() is the new base function for
install_special_mapping(). This function will return a pointer of the
created VMA or a error code in an ERR_PTR()

This new function will be needed by the for the vdso 32 bit support to map the
additonal vvar and hpet pages into the 32 bit address space. This will be done
with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 include/linux/mm.h |  3 +++
 mm/mmap.c          | 20 ++++++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c1b7414..6c7fedf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1750,6 +1750,9 @@ extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
 extern struct file *get_mm_exe_file(struct mm_struct *mm);
 
 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
+extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
+				   unsigned long addr, unsigned long len,
+				   unsigned long flags, struct page **pages);
 extern int install_special_mapping(struct mm_struct *mm,
 				   unsigned long addr, unsigned long len,
 				   unsigned long flags, struct page **pages);
diff --git a/mm/mmap.c b/mm/mmap.c
index 20ff0c3..81ba54f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2918,7 +2918,7 @@ static const struct vm_operations_struct special_mapping_vmops = {
  * The array pointer and the pages it points to are assumed to stay alive
  * for as long as this mapping might exist.
  */
-int install_special_mapping(struct mm_struct *mm,
+struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
 			    unsigned long addr, unsigned long len,
 			    unsigned long vm_flags, struct page **pages)
 {
@@ -2927,7 +2927,7 @@ int install_special_mapping(struct mm_struct *mm,
 
 	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 	if (unlikely(vma == NULL))
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&vma->anon_vma_chain);
 	vma->vm_mm = mm;
@@ -2948,11 +2948,23 @@ int install_special_mapping(struct mm_struct *mm,
 
 	perf_event_mmap(vma);
 
-	return 0;
+	return vma;
 
 out:
 	kmem_cache_free(vm_area_cachep, vma);
-	return ret;
+	return ERR_PTR(ret);
+}
+
+int install_special_mapping(struct mm_struct *mm,
+			    unsigned long addr, unsigned long len,
+			    unsigned long vm_flags, struct page **pages)
+{
+	struct vm_area_struct *vma = _install_special_mapping(mm,
+			    addr, len, vm_flags, pages);
+
+	if (IS_ERR(vma))
+		return PTR_ERR(vma);
+	return 0;
 }
 
 static DEFINE_MUTEX(mm_all_locks_mutex);
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 03/13] x86, vdso: Revamp vclock_gettime.c
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 01/13] x86, vdso: Make vsyscall_gtod_data handling x86 generic Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 02/13] mm: Add new func _install_special_mapping() to mmap.c Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 04/13] x86, vdso: __vdso_clock_gettime() cleanup Stefani Seibold
                   ` (9 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This intermediate patch revamps the vclock_gettime.c by moving some functions
around. It is only for spliting purpose, to make whole the 32 bit vdso timer
patch easier to review.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/vdso/vclock_gettime.c | 85 +++++++++++++++++++++---------------------
 1 file changed, 42 insertions(+), 43 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index eb5d7a5..bbc8065 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -26,41 +26,26 @@
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
-notrace static cycle_t vread_tsc(void)
+static notrace cycle_t vread_hpet(void)
 {
-	cycle_t ret;
-	u64 last;
-
-	/*
-	 * Empirically, a fence (of type that depends on the CPU)
-	 * before rdtsc is enough to ensure that rdtsc is ordered
-	 * with respect to loads.  The various CPU manuals are unclear
-	 * as to whether rdtsc can be reordered with later loads,
-	 * but no one has ever seen it happen.
-	 */
-	rdtsc_barrier();
-	ret = (cycle_t)vget_cycles();
-
-	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
-
-	if (likely(ret >= last))
-		return ret;
+	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+}
 
-	/*
-	 * GCC likes to generate cmov here, but this branch is extremely
-	 * predictable (it's just a funciton of time and the likely is
-	 * very likely) and there's a data dependence, so force GCC
-	 * to generate a branch instead.  I don't barrier() because
-	 * we don't actually need a barrier, and if this function
-	 * ever gets inlined it will generate worse code.
-	 */
-	asm volatile ("");
-	return last;
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+{
+	long ret;
+	asm("syscall" : "=a" (ret) :
+	    "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
+	return ret;
 }
 
-static notrace cycle_t vread_hpet(void)
+notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
 {
-	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+	long ret;
+
+	asm("syscall" : "=a" (ret) :
+	    "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
+	return ret;
 }
 
 #ifdef CONFIG_PARAVIRT_CLOCK
@@ -133,23 +118,37 @@ static notrace cycle_t vread_pvclock(int *mode)
 }
 #endif
 
-notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+notrace static cycle_t vread_tsc(void)
 {
-	long ret;
-	asm("syscall" : "=a" (ret) :
-	    "0" (__NR_clock_gettime),"D" (clock), "S" (ts) : "memory");
-	return ret;
-}
+	cycle_t ret;
+	u64 last;
 
-notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
-{
-	long ret;
+	/*
+	 * Empirically, a fence (of type that depends on the CPU)
+	 * before rdtsc is enough to ensure that rdtsc is ordered
+	 * with respect to loads.  The various CPU manuals are unclear
+	 * as to whether rdtsc can be reordered with later loads,
+	 * but no one has ever seen it happen.
+	 */
+	rdtsc_barrier();
+	ret = (cycle_t)vget_cycles();
 
-	asm("syscall" : "=a" (ret) :
-	    "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
-	return ret;
-}
+	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
 
+	if (likely(ret >= last))
+		return ret;
+
+	/*
+	 * GCC likes to generate cmov here, but this branch is extremely
+	 * predictable (it's just a funciton of time and the likely is
+	 * very likely) and there's a data dependence, so force GCC
+	 * to generate a branch instead.  I don't barrier() because
+	 * we don't actually need a barrier, and if this function
+	 * ever gets inlined it will generate worse code.
+	 */
+	asm volatile ("");
+	return last;
+}
 
 notrace static inline u64 vgetsns(int *mode)
 {
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 04/13] x86, vdso: __vdso_clock_gettime() cleanup
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (2 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 03/13] x86, vdso: Revamp vclock_gettime.c Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 05/13] x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro Stefani Seibold
                   ` (8 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch is a small code cleanup for the __vdso_clock_gettime() function.

It removes the unneeded return values from do_monotonic_coarse() and
do_realtime_coarse() and add a fallback label for doing the kernel
gettimeofday() system call.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/vdso/vclock_gettime.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index bbc8065..fd074dd 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -209,7 +209,7 @@ notrace static int do_monotonic(struct timespec *ts)
 	return mode;
 }
 
-notrace static int do_realtime_coarse(struct timespec *ts)
+notrace static void do_realtime_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
@@ -217,10 +217,9 @@ notrace static int do_realtime_coarse(struct timespec *ts)
 		ts->tv_sec = gtod->wall_time_coarse.tv_sec;
 		ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
 	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-	return 0;
 }
 
-notrace static int do_monotonic_coarse(struct timespec *ts)
+notrace static void do_monotonic_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
@@ -228,30 +227,32 @@ notrace static int do_monotonic_coarse(struct timespec *ts)
 		ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
 		ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
 	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-
-	return 0;
 }
 
 notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
 {
-	int ret = VCLOCK_NONE;
-
 	switch (clock) {
 	case CLOCK_REALTIME:
-		ret = do_realtime(ts);
+		if (do_realtime(ts) == VCLOCK_NONE)
+			goto fallback;
 		break;
 	case CLOCK_MONOTONIC:
-		ret = do_monotonic(ts);
+		if (do_monotonic(ts) == VCLOCK_NONE)
+			goto fallback;
 		break;
 	case CLOCK_REALTIME_COARSE:
-		return do_realtime_coarse(ts);
+		do_realtime_coarse(ts);
+		break;
 	case CLOCK_MONOTONIC_COARSE:
-		return do_monotonic_coarse(ts);
+		do_monotonic_coarse(ts);
+		break;
+	default:
+		goto fallback;
 	}
 
-	if (ret == VCLOCK_NONE)
-		return vdso_fallback_gettime(clock, ts);
 	return 0;
+fallback:
+	return vdso_fallback_gettime(clock, ts);
 }
 int clock_gettime(clockid_t, struct timespec *)
 	__attribute__((weak, alias("__vdso_clock_gettime")));
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 05/13] x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (3 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 04/13] x86, vdso: __vdso_clock_gettime() cleanup Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 06/13] x86, vdso: Cleanup __vdso_gettimeofday() Stefani Seibold
                   ` (7 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

There a currently more than 30 users of the gtod macro, so replace the
last VVAR(vsyscall_gtod_data) by gtod macro.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/vdso/vclock_gettime.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index fd074dd..743f277 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -109,7 +109,7 @@ static notrace cycle_t vread_pvclock(int *mode)
 		*mode = VCLOCK_NONE;
 
 	/* refer to tsc.c read_tsc() comment for rationale */
-	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
+	last = gtod->clock.cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -133,7 +133,7 @@ notrace static cycle_t vread_tsc(void)
 	rdtsc_barrier();
 	ret = (cycle_t)vget_cycles();
 
-	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
+	last = gtod->clock.cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -288,7 +288,7 @@ int gettimeofday(struct timeval *, struct timezone *)
 notrace time_t __vdso_time(time_t *t)
 {
 	/* This is atomic on x86_64 so we don't need any locks. */
-	time_t result = ACCESS_ONCE(VVAR(vsyscall_gtod_data).wall_time_sec);
+	time_t result = ACCESS_ONCE(gtod->wall_time_sec);
 
 	if (t)
 		*t = result;
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 06/13] x86, vdso: Cleanup __vdso_gettimeofday()
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (4 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 05/13] x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 07/13] x86, vdso: Introduce VVAR marco for vdso32 Stefani Seibold
                   ` (6 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch do a little cleanup for the __vdso_gettimeofday() function.

It kicks out an unneeded ret local variable and makes the code faster
if only the timezone is needed (an admittedly rare case.)

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/vdso/vclock_gettime.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 743f277..09dae4a 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -259,13 +259,12 @@ int clock_gettime(clockid_t, struct timespec *)
 
 notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
-	long ret = VCLOCK_NONE;
-
 	if (likely(tv != NULL)) {
 		BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
 			     offsetof(struct timespec, tv_nsec) ||
 			     sizeof(*tv) != sizeof(struct timespec));
-		ret = do_realtime((struct timespec *)tv);
+		if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
+			return vdso_fallback_gtod(tv, tz);
 		tv->tv_usec /= 1000;
 	}
 	if (unlikely(tz != NULL)) {
@@ -274,8 +273,6 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 		tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
 	}
 
-	if (ret == VCLOCK_NONE)
-		return vdso_fallback_gtod(tv, tz);
 	return 0;
 }
 int gettimeofday(struct timeval *, struct timezone *)
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 07/13] x86, vdso: Introduce VVAR marco for vdso32
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (5 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 06/13] x86, vdso: Cleanup __vdso_gettimeofday() Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 08/13] x86, vdso: Patch alternatives in the 32-bit VDSO Stefani Seibold
                   ` (5 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch revamps the vvar.h for introduce the VVAR macro for vdso32.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/include/asm/vvar.h | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 0a534ea..52c79ff 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -26,6 +26,15 @@
 
 #else
 
+#ifdef BUILD_VDSO32
+
+#define DECLARE_VVAR(offset, type, name)				\
+	extern type vvar_ ## name __attribute__((visibility("hidden")));
+
+#define VVAR(name) (vvar_ ## name)
+
+#else
+
 extern char __vvar_page;
 
 /* Base address of vvars.  This is not ABI. */
@@ -39,12 +48,13 @@ extern char __vvar_page;
 	static type const * const vvaraddr_ ## name =			\
 		(void *)(VVAR_ADDRESS + (offset));
 
+#define VVAR(name) (*vvaraddr_ ## name)
+#endif
+
 #define DEFINE_VVAR(type, name)						\
 	type name							\
 	__attribute__((section(".vvar_" #name), aligned(16))) __visible
 
-#define VVAR(name) (*vvaraddr_ ## name)
-
 #endif
 
 /* DECLARE_VVAR(offset, type, name) */
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 08/13] x86, vdso: Patch alternatives in the 32-bit VDSO
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (6 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 07/13] x86, vdso: Introduce VVAR marco for vdso32 Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
  2014-03-17 22:22 ` [PATCH v23 09/13] x86, vdso: Add 32 bit VDSO time support for 32 bit kernel Stefani Seibold
                   ` (4 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, stefani

From: Andy Lutomirski <luto@amacapital.net>

We need the alternatives mechanism for rdtsc_barrier() to work.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/include/asm/vdso.h  |  2 ++
 arch/x86/vdso/Makefile       |  3 ++-
 arch/x86/vdso/vdso32-setup.c | 23 ++++++++++++-----------
 arch/x86/vdso/vma.c          | 13 ++++++++++---
 4 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 5594e84..f8605e6 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -28,4 +28,6 @@ extern const char vdso32_int80_start, vdso32_int80_end;
 extern const char vdso32_syscall_start, vdso32_syscall_end;
 extern const char vdso32_sysenter_start, vdso32_sysenter_end;
 
+void __init patch_vdso32(void *vdso, size_t len);
+
 #endif /* _ASM_X86_VDSO_H */
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index fd14be1..7a3d13e 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -21,7 +21,8 @@ vobjs-$(VDSOX32-y) += $(vobjx32s-compat)
 vobj64s := $(filter-out $(vobjx32s-compat),$(vobjs-y))
 
 # files to link into kernel
-obj-$(VDSO64-y)			+= vma.o vdso.o
+obj-y				+= vma.o
+obj-$(VDSO64-y)			+= vdso.o
 obj-$(VDSOX32-y)		+= vdsox32.o
 obj-$(VDSO32-y)			+= vdso32.o vdso32-setup.o
 
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index ab20c04..e0fc767 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -112,24 +112,25 @@ void enable_sep_cpu(void)
 
 int __init sysenter_setup(void)
 {
-	void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
-	const void *vsyscall;
-	size_t vsyscall_len;
+	void *vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
+	const void *vdso;
+	size_t vdso_len;
 
-	vdso32_pages[0] = virt_to_page(syscall_page);
+	vdso32_pages[0] = virt_to_page(vdso_page);
 
 	if (vdso32_syscall()) {
-		vsyscall = &vdso32_syscall_start;
-		vsyscall_len = &vdso32_syscall_end - &vdso32_syscall_start;
+		vdso = &vdso32_syscall_start;
+		vdso_len = &vdso32_syscall_end - &vdso32_syscall_start;
 	} else if (vdso32_sysenter()){
-		vsyscall = &vdso32_sysenter_start;
-		vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
+		vdso = &vdso32_sysenter_start;
+		vdso_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
 	} else {
-		vsyscall = &vdso32_int80_start;
-		vsyscall_len = &vdso32_int80_end - &vdso32_int80_start;
+		vdso = &vdso32_int80_start;
+		vdso_len = &vdso32_int80_end - &vdso32_int80_start;
 	}
 
-	memcpy(syscall_page, vsyscall, vsyscall_len);
+	memcpy(vdso_page, vdso, vdso_len);
+	patch_vdso32(vdso_page, vdso_len);
 
 	return 0;
 }
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 431e875..7345bc9 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -16,6 +16,7 @@
 #include <asm/vdso.h>
 #include <asm/page.h>
 
+#if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso_enabled = 1;
 
 extern char vdso_start[], vdso_end[];
@@ -28,8 +29,12 @@ static unsigned vdso_size;
 extern char vdsox32_start[], vdsox32_end[];
 extern struct page *vdsox32_pages[];
 static unsigned vdsox32_size;
+#endif
+#endif
 
-static void __init patch_vdsox32(void *vdso, size_t len)
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_X32_ABI) || \
+	defined(CONFIG_COMPAT)
+void __init patch_vdso32(void *vdso, size_t len)
 {
 	Elf32_Ehdr *hdr = vdso;
 	Elf32_Shdr *sechdrs, *alt_sec = 0;
@@ -52,7 +57,7 @@ static void __init patch_vdsox32(void *vdso, size_t len)
 	}
 
 	/* If we get here, it's probably a bug. */
-	pr_warning("patch_vdsox32: .altinstructions not found\n");
+	pr_warning("patch_vdso32: .altinstructions not found\n");
 	return;  /* nothing to patch */
 
 found:
@@ -61,6 +66,7 @@ found:
 }
 #endif
 
+#if defined(CONFIG_X86_64)
 static void __init patch_vdso64(void *vdso, size_t len)
 {
 	Elf64_Ehdr *hdr = vdso;
@@ -104,7 +110,7 @@ static int __init init_vdso(void)
 		vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE);
 
 #ifdef CONFIG_X86_X32_ABI
-	patch_vdsox32(vdsox32_start, vdsox32_end - vdsox32_start);
+	patch_vdso32(vdsox32_start, vdsox32_end - vdsox32_start);
 	npages = (vdsox32_end - vdsox32_start + PAGE_SIZE - 1) / PAGE_SIZE;
 	vdsox32_size = npages << PAGE_SHIFT;
 	for (i = 0; i < npages; i++)
@@ -204,3 +210,4 @@ static __init int vdso_setup(char *s)
 	return 0;
 }
 __setup("vdso=", vdso_setup);
+#endif
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 09/13] x86, vdso: Add 32 bit VDSO time support for 32 bit kernel
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (7 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 08/13] x86, vdso: Patch alternatives in the 32-bit VDSO Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 " Stefani Seibold
                   ` (3 subsequent siblings)
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch add the time support for 32 bit a VDSO to a 32 bit kernel.

For 32 bit programs running on a 32 bit kernel, the same mechanism is
used as for 64 bit programs running on a 64 bit kernel.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/include/asm/vdso.h           |  5 +++
 arch/x86/include/asm/vdso32.h         | 11 +++++
 arch/x86/vdso/Makefile                |  8 ++++
 arch/x86/vdso/vclock_gettime.c        | 76 +++++++++++++++++++++++++++++++----
 arch/x86/vdso/vdso-layout.lds.S       | 22 ++++++++++
 arch/x86/vdso/vdso32-setup.c          | 47 ++++++++++++++++++++--
 arch/x86/vdso/vdso32/vclock_gettime.c |  9 +++++
 arch/x86/vdso/vdso32/vdso32.lds.S     | 11 +++++
 8 files changed, 178 insertions(+), 11 deletions(-)
 create mode 100644 arch/x86/include/asm/vdso32.h
 create mode 100644 arch/x86/vdso/vdso32/vclock_gettime.c

diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index f8605e6..bde4359 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -2,6 +2,11 @@
 #define _ASM_X86_VDSO_H
 
 #if defined CONFIG_X86_32 || defined CONFIG_COMPAT
+
+#include <asm/vdso32.h>
+
+extern const char VDSO32_PRELINK[];
+
 /*
  * Given a pointer to the vDSO image, find the pointer to VDSO32_name
  * as that symbol is defined in the vDSO sources or linker script.
diff --git a/arch/x86/include/asm/vdso32.h b/arch/x86/include/asm/vdso32.h
new file mode 100644
index 0000000..7efb701
--- /dev/null
+++ b/arch/x86/include/asm/vdso32.h
@@ -0,0 +1,11 @@
+#ifndef _ASM_X86_VDSO32_H
+#define _ASM_X86_VDSO32_H
+
+#define VDSO_BASE_PAGE	0
+#define VDSO_VVAR_PAGE	1
+#define VDSO_HPET_PAGE	2
+#define VDSO_PAGES	3
+#define VDSO_PREV_PAGES	2
+#define VDSO_OFFSET(x)	((x) * PAGE_SIZE)
+
+#endif
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 7a3d13e..6cef7a1 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -146,8 +146,16 @@ KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
 $(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
 $(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
 
+KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
+KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
+$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
+
 $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
 				 $(obj)/vdso32/vdso32.lds \
+				 $(obj)/vdso32/vclock_gettime.o \
 				 $(obj)/vdso32/note.o \
 				 $(obj)/vdso32/%.o
 	$(call if_changed,vdso)
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 09dae4a..90bb5e8 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -4,6 +4,9 @@
  *
  * Fast user context implementation of clock_gettime, gettimeofday, and time.
  *
+ * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
+ *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
+ *
  * The code should have no internal unresolved relocations.
  * Check with readelf after changing.
  */
@@ -12,13 +15,11 @@
 #define DISABLE_BRANCH_PROFILING
 
 #include <linux/kernel.h>
-#include <linux/posix-timers.h>
-#include <linux/time.h>
+#include <uapi/linux/time.h>
 #include <linux/string.h>
 #include <asm/vsyscall.h>
 #include <asm/fixmap.h>
 #include <asm/vgtod.h>
-#include <asm/timex.h>
 #include <asm/hpet.h>
 #include <asm/unistd.h>
 #include <asm/io.h>
@@ -26,6 +27,12 @@
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
+extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
+extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
+extern time_t __vdso_time(time_t *t);
+
+#ifndef BUILD_VDSO32
+
 static notrace cycle_t vread_hpet(void)
 {
 	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
@@ -118,6 +125,59 @@ static notrace cycle_t vread_pvclock(int *mode)
 }
 #endif
 
+#else
+
+extern u8 hpet_page
+	__attribute__((visibility("hidden")));
+
+#ifdef CONFIG_HPET_TIMER
+static notrace cycle_t vread_hpet(void)
+{
+	return readl((const void __iomem *)(&hpet_page + HPET_COUNTER));
+}
+#endif
+
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+{
+	long ret;
+
+	asm(
+		"mov %%ebx, %%edx \n"
+		"mov %2, %%ebx \n"
+		"call VDSO32_vsyscall \n"
+		"mov %%edx, %%ebx \n"
+		: "=a" (ret)
+		: "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
+		: "memory", "edx");
+	return ret;
+}
+
+notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
+{
+	long ret;
+
+	asm(
+		"mov %%ebx, %%edx \n"
+		"mov %2, %%ebx \n"
+		"call VDSO32_vsyscall \n"
+		"mov %%edx, %%ebx \n"
+		: "=a" (ret)
+		: "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
+		: "memory", "edx");
+	return ret;
+}
+
+#ifdef CONFIG_PARAVIRT_CLOCK
+
+static notrace cycle_t vread_pvclock(int *mode)
+{
+	*mode = VCLOCK_NONE;
+	return 0;
+}
+#endif
+
+#endif
+
 notrace static cycle_t vread_tsc(void)
 {
 	cycle_t ret;
@@ -131,7 +191,7 @@ notrace static cycle_t vread_tsc(void)
 	 * but no one has ever seen it happen.
 	 */
 	rdtsc_barrier();
-	ret = (cycle_t)vget_cycles();
+	ret = (cycle_t)__native_read_tsc();
 
 	last = gtod->clock.cycle_last;
 
@@ -152,12 +212,14 @@ notrace static cycle_t vread_tsc(void)
 
 notrace static inline u64 vgetsns(int *mode)
 {
-	long v;
+	u64 v;
 	cycles_t cycles;
 	if (gtod->clock.vclock_mode == VCLOCK_TSC)
 		cycles = vread_tsc();
+#ifdef CONFIG_HPET_TIMER
 	else if (gtod->clock.vclock_mode == VCLOCK_HPET)
 		cycles = vread_hpet();
+#endif
 #ifdef CONFIG_PARAVIRT_CLOCK
 	else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
 		cycles = vread_pvclock(mode);
@@ -189,7 +251,7 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
 	return mode;
 }
 
-notrace static int do_monotonic(struct timespec *ts)
+notrace static int __always_inline do_monotonic(struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;
@@ -284,7 +346,7 @@ int gettimeofday(struct timeval *, struct timezone *)
  */
 notrace time_t __vdso_time(time_t *t)
 {
-	/* This is atomic on x86_64 so we don't need any locks. */
+	/* This is atomic on x86 so we don't need any locks. */
 	time_t result = ACCESS_ONCE(gtod->wall_time_sec);
 
 	if (t)
diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S
index 8c550c1..c6d0e1b 100644
--- a/arch/x86/vdso/vdso-layout.lds.S
+++ b/arch/x86/vdso/vdso-layout.lds.S
@@ -6,6 +6,24 @@
 
 SECTIONS
 {
+#ifdef BUILD_VDSO32
+#include <asm/vdso32.h>
+
+	.hpet_sect : {
+		hpet_page = . - VDSO_OFFSET(VDSO_HPET_PAGE);
+	} :text :hpet_sect
+
+	.vvar_sect : {
+		vvar = . - VDSO_OFFSET(VDSO_VVAR_PAGE);
+
+	/* Place all vvars at the offsets in asm/vvar.h. */
+#define EMIT_VVAR(name, offset) vvar_ ## name = vvar + offset;
+#define __VVAR_KERNEL_LDS
+#include <asm/vvar.h>
+#undef __VVAR_KERNEL_LDS
+#undef EMIT_VVAR
+	} :text :vvar_sect
+#endif
 	. = SIZEOF_HEADERS;
 
 	.hash		: { *(.hash) }			:text
@@ -61,4 +79,8 @@ PHDRS
 	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
 	note		PT_NOTE		FLAGS(4);		/* PF_R */
 	eh_frame_hdr	PT_GNU_EH_FRAME;
+#ifdef BUILD_VDSO32
+	vvar_sect	PT_NULL		FLAGS(4);		/* PF_R */
+	hpet_sect	PT_NULL		FLAGS(4);		/* PF_R */
+#endif
 }
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e0fc767..e10abdf 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -25,6 +25,9 @@
 #include <asm/tlbflush.h>
 #include <asm/vdso.h>
 #include <asm/proto.h>
+#include <asm/fixmap.h>
+#include <asm/hpet.h>
+#include <asm/vvar.h>
 
 #ifdef CONFIG_COMPAT_VDSO
 #define VDSO_DEFAULT	0
@@ -141,6 +144,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	struct mm_struct *mm = current->mm;
 	unsigned long addr;
 	int ret = 0;
+	struct vm_area_struct *vma;
 
 #ifdef CONFIG_X86_X32_ABI
 	if (test_thread_flag(TIF_X32))
@@ -163,14 +167,49 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	/*
 	 * MAYWRITE to allow gdb to COW and set breakpoints
 	 */
-	ret = install_special_mapping(mm, addr, PAGE_SIZE,
-				      VM_READ|VM_EXEC|
-				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				      vdso32_pages);
+	ret = install_special_mapping(mm,
+			addr,
+			VDSO_OFFSET(VDSO_PAGES - VDSO_PREV_PAGES),
+			VM_READ|VM_EXEC|
+			VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+			vdso32_pages);
 
 	if (ret)
 		goto up_fail;
 
+	vma = _install_special_mapping(mm,
+			addr -  VDSO_OFFSET(VDSO_PREV_PAGES),
+			VDSO_OFFSET(VDSO_PREV_PAGES),
+			VM_READ,
+			NULL);
+
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto up_fail;
+	}
+
+	ret = remap_pfn_range(vma,
+		addr - VDSO_OFFSET(VDSO_VVAR_PAGE),
+		__pa_symbol(&__vvar_page) >> PAGE_SHIFT,
+		PAGE_SIZE,
+		PAGE_READONLY);
+
+	if (ret)
+		goto up_fail;
+
+#ifdef CONFIG_HPET_TIMER
+	if (hpet_address) {
+		ret = io_remap_pfn_range(vma,
+			addr - VDSO_OFFSET(VDSO_HPET_PAGE),
+			hpet_address >> PAGE_SHIFT,
+			PAGE_SIZE,
+			pgprot_noncached(PAGE_READONLY));
+
+		if (ret)
+			goto up_fail;
+	}
+#endif
+
 	current_thread_info()->sysenter_return =
 		VDSO32_SYMBOL(addr, SYSENTER_RETURN);
 
diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c b/arch/x86/vdso/vdso32/vclock_gettime.c
new file mode 100644
index 0000000..ca65e42
--- /dev/null
+++ b/arch/x86/vdso/vdso32/vclock_gettime.c
@@ -0,0 +1,9 @@
+#define BUILD_VDSO32
+
+#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
+#undef CONFIG_OPTIMIZE_INLINING
+#endif
+
+#undef CONFIG_X86_PPRO_FENCE
+
+#include "../vclock_gettime.c"
diff --git a/arch/x86/vdso/vdso32/vdso32.lds.S b/arch/x86/vdso/vdso32/vdso32.lds.S
index 90e7aa9..28c4607 100644
--- a/arch/x86/vdso/vdso32/vdso32.lds.S
+++ b/arch/x86/vdso/vdso32/vdso32.lds.S
@@ -8,6 +8,11 @@
  * values visible using the asm-x86/vdso.h macros from the kernel proper.
  */
 
+#include <asm/page.h>
+
+#define BUILD_VDSO32
+#define VDSO_PRELINK 0
+
 #include "../vdso-layout.lds.S"
 
 /* The ELF entry point can be used to set the AT_SYSINFO value.  */
@@ -23,6 +28,9 @@ VERSION
 		__kernel_vsyscall;
 		__kernel_sigreturn;
 		__kernel_rt_sigreturn;
+		__vdso_clock_gettime;
+		__vdso_gettimeofday;
+		__vdso_time;
 	local: *;
 	};
 }
@@ -33,3 +41,6 @@ VERSION
 VDSO32_vsyscall		= __kernel_vsyscall;
 VDSO32_sigreturn	= __kernel_sigreturn;
 VDSO32_rt_sigreturn	= __kernel_rt_sigreturn;
+VDSO32_clock_gettime	= clock_gettime;
+VDSO32_gettimeofday	= gettimeofday;
+VDSO32_time		= time;
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (8 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 09/13] x86, vdso: Add 32 bit VDSO time support for 32 bit kernel Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  2014-03-27 20:44   ` [PATCH v23 10/13] " John Stultz
  2014-03-17 22:22 ` [PATCH v23 11/13] x86, vdso: Zero-pad the VVAR page Stefani Seibold
                   ` (2 subsequent siblings)
  12 siblings, 2 replies; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch add the VDSO time support for the IA32 Emulation Layer.

Due the nature of the kernel headers and the LP64 compiler where the
size of a long and a pointer differs against a 32 bit compiler, there
is some type hacking necessary for optimal performance.

The vsyscall_gtod_data struture must be a rearranged to serve 32- and
64-bit code access at the same time:

- The seqcount_t was replaced by an unsigned, this makes the
  vsyscall_gtod_data intedepend of kernel configuration and internal functions.
- All kernel internal structures are replaced by fix size elements
  which works for 32- and 64-bit access
- The inner struct clock was removed to pack the whole struct.

The "unsigned seq" would be handled by functions derivated from seqcount_t.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/include/asm/vgtod.h          | 71 +++++++++++++++++++++------
 arch/x86/include/asm/vvar.h           |  5 ++
 arch/x86/kernel/vsyscall_gtod.c       | 34 ++++++++-----
 arch/x86/vdso/vclock_gettime.c        | 91 +++++++++++++++++++----------------
 arch/x86/vdso/vdso32/vclock_gettime.c | 21 ++++++++
 5 files changed, 155 insertions(+), 67 deletions(-)

diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index 46e24d3..3c3366c 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -1,30 +1,73 @@
 #ifndef _ASM_X86_VGTOD_H
 #define _ASM_X86_VGTOD_H
 
-#include <asm/vsyscall.h>
+#include <linux/compiler.h>
 #include <linux/clocksource.h>
 
+#ifdef BUILD_VDSO32_64
+typedef u64 gtod_long_t;
+#else
+typedef unsigned long gtod_long_t;
+#endif
+/*
+ * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
+ * so be carefull by modifying this structure.
+ */
 struct vsyscall_gtod_data {
-	seqcount_t	seq;
+	unsigned seq;
 
-	struct { /* extract of a clocksource struct */
-		int vclock_mode;
-		cycle_t	cycle_last;
-		cycle_t	mask;
-		u32	mult;
-		u32	shift;
-	} clock;
+	int vclock_mode;
+	cycle_t	cycle_last;
+	cycle_t	mask;
+	u32	mult;
+	u32	shift;
 
 	/* open coded 'struct timespec' */
-	time_t		wall_time_sec;
 	u64		wall_time_snsec;
+	gtod_long_t	wall_time_sec;
+	gtod_long_t	monotonic_time_sec;
 	u64		monotonic_time_snsec;
-	time_t		monotonic_time_sec;
+	gtod_long_t	wall_time_coarse_sec;
+	gtod_long_t	wall_time_coarse_nsec;
+	gtod_long_t	monotonic_time_coarse_sec;
+	gtod_long_t	monotonic_time_coarse_nsec;
 
-	struct timezone sys_tz;
-	struct timespec wall_time_coarse;
-	struct timespec monotonic_time_coarse;
+	int		tz_minuteswest;
+	int		tz_dsttime;
 };
 extern struct vsyscall_gtod_data vsyscall_gtod_data;
 
+static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
+{
+	unsigned ret;
+
+repeat:
+	ret = ACCESS_ONCE(s->seq);
+	if (unlikely(ret & 1)) {
+		cpu_relax();
+		goto repeat;
+	}
+	smp_rmb();
+	return ret;
+}
+
+static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
+					unsigned start)
+{
+	smp_rmb();
+	return unlikely(s->seq != start);
+}
+
+static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
+{
+	++s->seq;
+	smp_wmb();
+}
+
+static inline void gtod_write_end(struct vsyscall_gtod_data *s)
+{
+	smp_wmb();
+	++s->seq;
+}
+
 #endif /* _ASM_X86_VGTOD_H */
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 52c79ff..081d909 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -16,6 +16,9 @@
  * you mess up, the linker will catch it.)
  */
 
+#ifndef _ASM_X86_VVAR_H
+#define _ASM_X86_VVAR_H
+
 #if defined(__VVAR_KERNEL_LDS)
 
 /* The kernel linker script defines its own magic to put vvars in the
@@ -64,3 +67,5 @@ DECLARE_VVAR(16, int, vgetcpu_mode)
 DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data)
 
 #undef DECLARE_VVAR
+
+#endif
diff --git a/arch/x86/kernel/vsyscall_gtod.c b/arch/x86/kernel/vsyscall_gtod.c
index b5a943d..f9c6e56 100644
--- a/arch/x86/kernel/vsyscall_gtod.c
+++ b/arch/x86/kernel/vsyscall_gtod.c
@@ -4,6 +4,7 @@
  *
  *  Modified for x86 32 bit architecture by
  *  Stefani Seibold <stefani@seibold.net>
+ *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
  *
  *  Thanks to hpa@transmeta.com for some useful hint.
  *  Special thanks to Ingo Molnar for his early experience with
@@ -13,26 +14,28 @@
 
 #include <linux/timekeeper_internal.h>
 #include <asm/vgtod.h>
+#include <asm/vvar.h>
 
 DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
 
 void update_vsyscall_tz(void)
 {
-	vsyscall_gtod_data.sys_tz = sys_tz;
+	vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest;
+	vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime;
 }
 
 void update_vsyscall(struct timekeeper *tk)
 {
 	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
 
-	write_seqcount_begin(&vdata->seq);
+	gtod_write_begin(vdata);
 
 	/* copy vsyscall data */
-	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;
-	vdata->clock.cycle_last		= tk->clock->cycle_last;
-	vdata->clock.mask		= tk->clock->mask;
-	vdata->clock.mult		= tk->mult;
-	vdata->clock.shift		= tk->shift;
+	vdata->vclock_mode	= tk->clock->archdata.vclock_mode;
+	vdata->cycle_last	= tk->clock->cycle_last;
+	vdata->mask		= tk->clock->mask;
+	vdata->mult		= tk->mult;
+	vdata->shift		= tk->shift;
 
 	vdata->wall_time_sec		= tk->xtime_sec;
 	vdata->wall_time_snsec		= tk->xtime_nsec;
@@ -49,11 +52,18 @@ void update_vsyscall(struct timekeeper *tk)
 		vdata->monotonic_time_sec++;
 	}
 
-	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;
-	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);
+	vdata->wall_time_coarse_sec	= tk->xtime_sec;
+	vdata->wall_time_coarse_nsec	= (long)(tk->xtime_nsec >> tk->shift);
 
-	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,
-							tk->wall_to_monotonic);
+	vdata->monotonic_time_coarse_sec =
+		vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec;
+	vdata->monotonic_time_coarse_nsec =
+		vdata->wall_time_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
 
-	write_seqcount_end(&vdata->seq);
+	while (vdata->monotonic_time_coarse_nsec >= NSEC_PER_SEC) {
+		vdata->monotonic_time_coarse_nsec -= NSEC_PER_SEC;
+		vdata->monotonic_time_coarse_sec++;
+	}
+
+	gtod_write_end(vdata);
 }
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 90bb5e8..16d6861 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -14,16 +14,14 @@
 /* Disable profiling for userspace code: */
 #define DISABLE_BRANCH_PROFILING
 
-#include <linux/kernel.h>
 #include <uapi/linux/time.h>
-#include <linux/string.h>
-#include <asm/vsyscall.h>
-#include <asm/fixmap.h>
 #include <asm/vgtod.h>
 #include <asm/hpet.h>
+#include <asm/vvar.h>
 #include <asm/unistd.h>
-#include <asm/io.h>
-#include <asm/pvclock.h>
+#include <asm/msr.h>
+#include <linux/math64.h>
+#include <linux/time.h>
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
@@ -31,11 +29,23 @@ extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
 extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
 extern time_t __vdso_time(time_t *t);
 
+#ifdef CONFIG_HPET_TIMER
+static inline u32 read_hpet_counter(const volatile void *addr)
+{
+	return *(const volatile u32 *) (addr + HPET_COUNTER);
+}
+#endif
+
 #ifndef BUILD_VDSO32
 
+#include <linux/kernel.h>
+#include <asm/vsyscall.h>
+#include <asm/fixmap.h>
+#include <asm/pvclock.h>
+
 static notrace cycle_t vread_hpet(void)
 {
-	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+	return read_hpet_counter((const void *)fix_to_virt(VSYSCALL_HPET));
 }
 
 notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
@@ -116,7 +126,7 @@ static notrace cycle_t vread_pvclock(int *mode)
 		*mode = VCLOCK_NONE;
 
 	/* refer to tsc.c read_tsc() comment for rationale */
-	last = gtod->clock.cycle_last;
+	last = gtod->cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -133,7 +143,7 @@ extern u8 hpet_page
 #ifdef CONFIG_HPET_TIMER
 static notrace cycle_t vread_hpet(void)
 {
-	return readl((const void __iomem *)(&hpet_page + HPET_COUNTER));
+	return read_hpet_counter((const void *)(&hpet_page));
 }
 #endif
 
@@ -193,7 +203,7 @@ notrace static cycle_t vread_tsc(void)
 	rdtsc_barrier();
 	ret = (cycle_t)__native_read_tsc();
 
-	last = gtod->clock.cycle_last;
+	last = gtod->cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -214,20 +224,21 @@ notrace static inline u64 vgetsns(int *mode)
 {
 	u64 v;
 	cycles_t cycles;
-	if (gtod->clock.vclock_mode == VCLOCK_TSC)
+
+	if (gtod->vclock_mode == VCLOCK_TSC)
 		cycles = vread_tsc();
 #ifdef CONFIG_HPET_TIMER
-	else if (gtod->clock.vclock_mode == VCLOCK_HPET)
+	else if (gtod->vclock_mode == VCLOCK_HPET)
 		cycles = vread_hpet();
 #endif
 #ifdef CONFIG_PARAVIRT_CLOCK
-	else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
+	else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
 		cycles = vread_pvclock(mode);
 #endif
 	else
 		return 0;
-	v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask;
-	return v * gtod->clock.mult;
+	v = (cycles - gtod->cycle_last) & gtod->mask;
+	return v * gtod->mult;
 }
 
 /* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
@@ -237,17 +248,18 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
 	u64 ns;
 	int mode;
 
-	ts->tv_nsec = 0;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		mode = gtod->clock.vclock_mode;
+		seq = gtod_read_begin(gtod);
+		mode = gtod->vclock_mode;
 		ts->tv_sec = gtod->wall_time_sec;
 		ns = gtod->wall_time_snsec;
 		ns += vgetsns(&mode);
-		ns >>= gtod->clock.shift;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+		ns >>= gtod->shift;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
+
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
 
-	timespec_add_ns(ts, ns);
 	return mode;
 }
 
@@ -257,16 +269,17 @@ notrace static int __always_inline do_monotonic(struct timespec *ts)
 	u64 ns;
 	int mode;
 
-	ts->tv_nsec = 0;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		mode = gtod->clock.vclock_mode;
+		seq = gtod_read_begin(gtod);
+		mode = gtod->vclock_mode;
 		ts->tv_sec = gtod->monotonic_time_sec;
 		ns = gtod->monotonic_time_snsec;
 		ns += vgetsns(&mode);
-		ns >>= gtod->clock.shift;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-	timespec_add_ns(ts, ns);
+		ns >>= gtod->shift;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
+
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
 
 	return mode;
 }
@@ -275,20 +288,20 @@ notrace static void do_realtime_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		ts->tv_sec = gtod->wall_time_coarse.tv_sec;
-		ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+		seq = gtod_read_begin(gtod);
+		ts->tv_sec = gtod->wall_time_coarse_sec;
+		ts->tv_nsec = gtod->wall_time_coarse_nsec;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
 }
 
 notrace static void do_monotonic_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
-		ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+		seq = gtod_read_begin(gtod);
+		ts->tv_sec = gtod->monotonic_time_coarse_sec;
+		ts->tv_nsec = gtod->monotonic_time_coarse_nsec;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
 }
 
 notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
@@ -322,17 +335,13 @@ int clock_gettime(clockid_t, struct timespec *)
 notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	if (likely(tv != NULL)) {
-		BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
-			     offsetof(struct timespec, tv_nsec) ||
-			     sizeof(*tv) != sizeof(struct timespec));
 		if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
 			return vdso_fallback_gtod(tv, tz);
 		tv->tv_usec /= 1000;
 	}
 	if (unlikely(tz != NULL)) {
-		/* Avoid memcpy. Some old compilers fail to inline it */
-		tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;
-		tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
+		tz->tz_minuteswest = gtod->tz_minuteswest;
+		tz->tz_dsttime = gtod->tz_dsttime;
 	}
 
 	return 0;
diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c b/arch/x86/vdso/vdso32/vclock_gettime.c
index ca65e42..175cc72 100644
--- a/arch/x86/vdso/vdso32/vclock_gettime.c
+++ b/arch/x86/vdso/vdso32/vclock_gettime.c
@@ -6,4 +6,25 @@
 
 #undef CONFIG_X86_PPRO_FENCE
 
+#ifdef CONFIG_X86_64
+
+/*
+ * in case of a 32 bit VDSO for a 64 bit kernel fake a 32 bit kernel
+ * configuration
+ */
+#undef CONFIG_64BIT
+#undef CONFIG_X86_64
+#undef CONFIG_ILLEGAL_POINTER_VALUE
+#undef CONFIG_SPARSEMEM_VMEMMAP
+#undef CONFIG_NR_CPUS
+
+#define CONFIG_X86_32 1
+#define CONFIG_PAGE_OFFSET 0
+#define CONFIG_ILLEGAL_POINTER_VALUE 0
+#define CONFIG_NR_CPUS 1
+
+#define BUILD_VDSO32_64
+
+#endif
+
 #include "../vclock_gettime.c"
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 11/13] x86, vdso: Zero-pad the VVAR page
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (9 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 " Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
  2014-03-17 22:22 ` [PATCH v23 12/13] x86, vdso32: Disable stack protector, adjust optimizations Stefani Seibold
  2014-03-17 22:22 ` [PATCH v23 13/13] x86, vdso32: handle 32 bit vDSO larger one page Stefani Seibold
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, stefani

From: Andy Lutomirski <luto@amacapital.net>

By coincidence, the VVAR page is at the end of an ELF segment.  As a
result, if it ends up being a partial page, the kernel loader will
leave garbage behind at the end of the vvar page.  Zero-pad it to a
full page to fix this issue.

This has probably been broken since the VVAR page was introduced.
On QEMU, if you dump the run-time contents of the VVAR page, you can
find entertaining strings from seabios left behind.

It's remotely possible that this is a security bug -- conceivably
there's some BIOS out there that leaves something sensitive in the
few K of memory that is exposed to userspace.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/kernel/vmlinux.lds.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 1d4897b..49edf2d 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -164,6 +164,11 @@ SECTIONS
 #undef __VVAR_KERNEL_LDS
 #undef EMIT_VVAR
 
+		/*
+		 * Pad the rest of the page with zeros.  Otherwise the loader
+		 * can leave garbage here.
+		 */
+		. = __vvar_beginning_hack + PAGE_SIZE;
 	} :data
 
        . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 12/13] x86, vdso32: Disable stack protector, adjust optimizations
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (10 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 11/13] x86, vdso: Zero-pad the VVAR page Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for H. Peter Anvin
  2014-03-17 22:22 ` [PATCH v23 13/13] x86, vdso32: handle 32 bit vDSO larger one page Stefani Seibold
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, H. Peter Anvin, stefani

From: "H. Peter Anvin" <hpa@linux.intel.com>

For the 32-bit VDSO, match the 64-bit VDSO in:

1. Disable the stack protector.
2. Use -fno-omit-frame-pointer for user space debugging sanity.
3. Use -foptimize-sibling-calls like the 64-bit VDSO does.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/vdso/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 6cef7a1..55e76eb 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -151,6 +151,9 @@ KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
+KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) 
+KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
+KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 
 $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH v23 13/13] x86, vdso32: handle 32 bit vDSO larger one page
  2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
                   ` (11 preceding siblings ...)
  2014-03-17 22:22 ` [PATCH v23 12/13] x86, vdso32: Disable stack protector, adjust optimizations Stefani Seibold
@ 2014-03-17 22:22 ` Stefani Seibold
  2014-03-18 21:30   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
  12 siblings, 1 reply; 30+ messages in thread
From: Stefani Seibold @ 2014-03-17 22:22 UTC (permalink / raw)
  To: gregkh, linux-kernel, x86, tglx, mingo, hpa, ak, aarcange,
	john.stultz, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief, Stefani Seibold

This patch enables 32 bit vDSO which are larger than a page.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 arch/x86/vdso/vdso32-setup.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e10abdf..0bc363a 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -16,6 +16,7 @@
 #include <linux/mm.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 
 #include <asm/cpufeature.h>
 #include <asm/msr.h>
@@ -69,7 +70,8 @@ __setup_param("vdso=", vdso32_setup, vdso_setup, 0);
 EXPORT_SYMBOL_GPL(vdso_enabled);
 #endif
 
-static struct page *vdso32_pages[1];
+static struct page **vdso32_pages;
+static unsigned int vdso32_size;
 
 #ifdef CONFIG_X86_64
 
@@ -115,11 +117,10 @@ void enable_sep_cpu(void)
 
 int __init sysenter_setup(void)
 {
-	void *vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
+	void *vdso_pages;
 	const void *vdso;
 	size_t vdso_len;
-
-	vdso32_pages[0] = virt_to_page(vdso_page);
+	unsigned int i;
 
 	if (vdso32_syscall()) {
 		vdso = &vdso32_syscall_start;
@@ -132,8 +133,15 @@ int __init sysenter_setup(void)
 		vdso_len = &vdso32_int80_end - &vdso32_int80_start;
 	}
 
-	memcpy(vdso_page, vdso, vdso_len);
-	patch_vdso32(vdso_page, vdso_len);
+	vdso32_size = (vdso_len + PAGE_SIZE - 1) / PAGE_SIZE;
+	vdso32_pages = kmalloc(sizeof(*vdso32_pages) * vdso32_size, GFP_ATOMIC); 
+	vdso_pages = kmalloc(VDSO_OFFSET(vdso32_size), GFP_ATOMIC);
+
+	for(i = 0; i != vdso32_size; ++i)
+		vdso32_pages[i] = virt_to_page(vdso_pages + VDSO_OFFSET(i));
+
+	memcpy(vdso_pages, vdso, vdso_len);
+	patch_vdso32(vdso_pages, vdso_len);
 
 	return 0;
 }
@@ -169,7 +177,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	 */
 	ret = install_special_mapping(mm,
 			addr,
-			VDSO_OFFSET(VDSO_PAGES - VDSO_PREV_PAGES),
+			VDSO_OFFSET(vdso32_size),
 			VM_READ|VM_EXEC|
 			VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
 			vdso32_pages);
-- 
1.9.0


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Make vsyscall_gtod_data handling x86 generic
  2014-03-17 22:22 ` [PATCH v23 01/13] x86, vdso: Make vsyscall_gtod_data handling x86 generic Stefani Seibold
@ 2014-03-18 21:27   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:27 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  d2312e3379d581d2c3603357a0181046448e1de3
Gitweb:     http://git.kernel.org/tip/d2312e3379d581d2c3603357a0181046448e1de3
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:01 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:51:52 -0700

x86, vdso: Make vsyscall_gtod_data handling x86 generic

This patch move the vsyscall_gtod_data handling out of vsyscall_64.c
into an additonal file vsyscall_gtod.c to make the functionality
available for x86 32 bit kernel.

It also adds a new vsyscall_32.c which setup the VVAR page.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-2-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/Kconfig                   |  4 +--
 arch/x86/include/asm/clocksource.h |  4 ---
 arch/x86/include/asm/vvar.h        | 12 ++++++--
 arch/x86/kernel/Makefile           |  2 +-
 arch/x86/kernel/hpet.c             |  2 --
 arch/x86/kernel/tsc.c              |  2 --
 arch/x86/kernel/vmlinux.lds.S      |  3 --
 arch/x86/kernel/vsyscall_64.c      | 45 -----------------------------
 arch/x86/kernel/vsyscall_gtod.c    | 59 ++++++++++++++++++++++++++++++++++++++
 arch/x86/tools/relocs.c            |  2 +-
 10 files changed, 72 insertions(+), 63 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9122f6b..ab3ebc8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -107,9 +107,9 @@ config X86
 	select HAVE_ARCH_SOFT_DIRTY
 	select CLOCKSOURCE_WATCHDOG
 	select GENERIC_CLOCKEVENTS
-	select ARCH_CLOCKSOURCE_DATA if X86_64
+	select ARCH_CLOCKSOURCE_DATA
 	select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
-	select GENERIC_TIME_VSYSCALL if X86_64
+	select GENERIC_TIME_VSYSCALL
 	select KTIME_SCALAR if X86_32
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
diff --git a/arch/x86/include/asm/clocksource.h b/arch/x86/include/asm/clocksource.h
index 16a57f4..eda81dc 100644
--- a/arch/x86/include/asm/clocksource.h
+++ b/arch/x86/include/asm/clocksource.h
@@ -3,8 +3,6 @@
 #ifndef _ASM_X86_CLOCKSOURCE_H
 #define _ASM_X86_CLOCKSOURCE_H
 
-#ifdef CONFIG_X86_64
-
 #define VCLOCK_NONE 0  /* No vDSO clock available.	*/
 #define VCLOCK_TSC  1  /* vDSO should use vread_tsc.	*/
 #define VCLOCK_HPET 2  /* vDSO should use vread_hpet.	*/
@@ -14,6 +12,4 @@ struct arch_clocksource_data {
 	int vclock_mode;
 };
 
-#endif /* CONFIG_X86_64 */
-
 #endif /* _ASM_X86_CLOCKSOURCE_H */
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index d76ac40..0a534ea 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -16,9 +16,6 @@
  * you mess up, the linker will catch it.)
  */
 
-/* Base address of vvars.  This is not ABI. */
-#define VVAR_ADDRESS (-10*1024*1024 - 4096)
-
 #if defined(__VVAR_KERNEL_LDS)
 
 /* The kernel linker script defines its own magic to put vvars in the
@@ -29,6 +26,15 @@
 
 #else
 
+extern char __vvar_page;
+
+/* Base address of vvars.  This is not ABI. */
+#ifdef CONFIG_X86_64
+#define VVAR_ADDRESS (-10*1024*1024 - 4096)
+#else
+#define VVAR_ADDRESS (&__vvar_page)
+#endif
+
 #define DECLARE_VVAR(offset, type, name)				\
 	static type const * const vvaraddr_ ## name =			\
 		(void *)(VVAR_ADDRESS + (offset));
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index cb648c8..f4d9600 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -26,7 +26,7 @@ obj-$(CONFIG_IRQ_WORK)  += irq_work.o
 obj-y			+= probe_roms.o
 obj-$(CONFIG_X86_32)	+= i386_ksyms_32.o
 obj-$(CONFIG_X86_64)	+= sys_x86_64.o x8664_ksyms_64.o
-obj-y			+= syscall_$(BITS).o
+obj-y			+= syscall_$(BITS).o vsyscall_gtod.o
 obj-$(CONFIG_X86_64)	+= vsyscall_64.o
 obj-$(CONFIG_X86_64)	+= vsyscall_emu_64.o
 obj-$(CONFIG_SYSFS)	+= ksysfs.o
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index da85a8e..e4b86ab 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -752,9 +752,7 @@ static struct clocksource clocksource_hpet = {
 	.mask		= HPET_MASK,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= hpet_resume_counter,
-#ifdef CONFIG_X86_64
 	.archdata	= { .vclock_mode = VCLOCK_HPET },
-#endif
 };
 
 static int hpet_clocksource_register(void)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index cfbe99f..227dcfc 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -985,9 +985,7 @@ static struct clocksource clocksource_tsc = {
 	.mask                   = CLOCKSOURCE_MASK(64),
 	.flags                  = CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
-#ifdef CONFIG_X86_64
 	.archdata               = { .vclock_mode = VCLOCK_TSC },
-#endif
 };
 
 void mark_tsc_unstable(char *reason)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index da6b35a..1d4897b 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -147,7 +147,6 @@ SECTIONS
 		_edata = .;
 	} :data
 
-#ifdef CONFIG_X86_64
 
 	. = ALIGN(PAGE_SIZE);
 	__vvar_page = .;
@@ -169,8 +168,6 @@ SECTIONS
 
        . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
 
-#endif /* CONFIG_X86_64 */
-
 	/* Init code and data - will be freed after init */
 	. = ALIGN(PAGE_SIZE);
 	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 1f96f93..9ea2876 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -47,14 +47,12 @@
 #include <asm/segment.h>
 #include <asm/desc.h>
 #include <asm/topology.h>
-#include <asm/vgtod.h>
 #include <asm/traps.h>
 
 #define CREATE_TRACE_POINTS
 #include "vsyscall_trace.h"
 
 DEFINE_VVAR(int, vgetcpu_mode);
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
 
 static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
 
@@ -77,48 +75,6 @@ static int __init vsyscall_setup(char *str)
 }
 early_param("vsyscall", vsyscall_setup);
 
-void update_vsyscall_tz(void)
-{
-	vsyscall_gtod_data.sys_tz = sys_tz;
-}
-
-void update_vsyscall(struct timekeeper *tk)
-{
-	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
-
-	write_seqcount_begin(&vdata->seq);
-
-	/* copy vsyscall data */
-	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;
-	vdata->clock.cycle_last		= tk->clock->cycle_last;
-	vdata->clock.mask		= tk->clock->mask;
-	vdata->clock.mult		= tk->mult;
-	vdata->clock.shift		= tk->shift;
-
-	vdata->wall_time_sec		= tk->xtime_sec;
-	vdata->wall_time_snsec		= tk->xtime_nsec;
-
-	vdata->monotonic_time_sec	= tk->xtime_sec
-					+ tk->wall_to_monotonic.tv_sec;
-	vdata->monotonic_time_snsec	= tk->xtime_nsec
-					+ (tk->wall_to_monotonic.tv_nsec
-						<< tk->shift);
-	while (vdata->monotonic_time_snsec >=
-					(((u64)NSEC_PER_SEC) << tk->shift)) {
-		vdata->monotonic_time_snsec -=
-					((u64)NSEC_PER_SEC) << tk->shift;
-		vdata->monotonic_time_sec++;
-	}
-
-	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;
-	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);
-
-	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,
-							tk->wall_to_monotonic);
-
-	write_seqcount_end(&vdata->seq);
-}
-
 static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
 			      const char *message)
 {
@@ -374,7 +330,6 @@ void __init map_vsyscall(void)
 {
 	extern char __vsyscall_page;
 	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
-	extern char __vvar_page;
 	unsigned long physaddr_vvar_page = __pa_symbol(&__vvar_page);
 
 	__set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_vsyscall,
diff --git a/arch/x86/kernel/vsyscall_gtod.c b/arch/x86/kernel/vsyscall_gtod.c
new file mode 100644
index 0000000..b5a943d
--- /dev/null
+++ b/arch/x86/kernel/vsyscall_gtod.c
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ *  Copyright 2003 Andi Kleen, SuSE Labs.
+ *
+ *  Modified for x86 32 bit architecture by
+ *  Stefani Seibold <stefani@seibold.net>
+ *
+ *  Thanks to hpa@transmeta.com for some useful hint.
+ *  Special thanks to Ingo Molnar for his early experience with
+ *  a different vsyscall implementation for Linux/IA32 and for the name.
+ *
+ */
+
+#include <linux/timekeeper_internal.h>
+#include <asm/vgtod.h>
+
+DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
+
+void update_vsyscall_tz(void)
+{
+	vsyscall_gtod_data.sys_tz = sys_tz;
+}
+
+void update_vsyscall(struct timekeeper *tk)
+{
+	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
+
+	write_seqcount_begin(&vdata->seq);
+
+	/* copy vsyscall data */
+	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;
+	vdata->clock.cycle_last		= tk->clock->cycle_last;
+	vdata->clock.mask		= tk->clock->mask;
+	vdata->clock.mult		= tk->mult;
+	vdata->clock.shift		= tk->shift;
+
+	vdata->wall_time_sec		= tk->xtime_sec;
+	vdata->wall_time_snsec		= tk->xtime_nsec;
+
+	vdata->monotonic_time_sec	= tk->xtime_sec
+					+ tk->wall_to_monotonic.tv_sec;
+	vdata->monotonic_time_snsec	= tk->xtime_nsec
+					+ (tk->wall_to_monotonic.tv_nsec
+						<< tk->shift);
+	while (vdata->monotonic_time_snsec >=
+					(((u64)NSEC_PER_SEC) << tk->shift)) {
+		vdata->monotonic_time_snsec -=
+					((u64)NSEC_PER_SEC) << tk->shift;
+		vdata->monotonic_time_sec++;
+	}
+
+	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;
+	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);
+
+	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,
+							tk->wall_to_monotonic);
+
+	write_seqcount_end(&vdata->seq);
+}
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index cfbdbdb..bbb1d22 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -69,8 +69,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"__per_cpu_load|"
 	"init_per_cpu__.*|"
 	"__end_rodata_hpage_align|"
-	"__vvar_page|"
 #endif
+	"__vvar_page|"
 	"_end)$"
 };
 

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] mm: Add new func _install_special_mapping() to mmap.c
  2014-03-17 22:22 ` [PATCH v23 02/13] mm: Add new func _install_special_mapping() to mmap.c Stefani Seibold
@ 2014-03-18 21:28   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:28 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  3935ed6a3a533c1736e3ca65bff72afd1773be27
Gitweb:     http://git.kernel.org/tip/3935ed6a3a533c1736e3ca65bff72afd1773be27
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:02 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:51:56 -0700

mm: Add new func _install_special_mapping() to mmap.c

The _install_special_mapping() is the new base function for
install_special_mapping(). This function will return a pointer of the
created VMA or a error code in an ERR_PTR()

This new function will be needed by the for the vdso 32 bit support to map the
additonal vvar and hpet pages into the 32 bit address space. This will be done
with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 include/linux/mm.h |  3 +++
 mm/mmap.c          | 20 ++++++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c1b7414..6c7fedf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1750,6 +1750,9 @@ extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
 extern struct file *get_mm_exe_file(struct mm_struct *mm);
 
 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
+extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
+				   unsigned long addr, unsigned long len,
+				   unsigned long flags, struct page **pages);
 extern int install_special_mapping(struct mm_struct *mm,
 				   unsigned long addr, unsigned long len,
 				   unsigned long flags, struct page **pages);
diff --git a/mm/mmap.c b/mm/mmap.c
index 20ff0c3..81ba54f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2918,7 +2918,7 @@ static const struct vm_operations_struct special_mapping_vmops = {
  * The array pointer and the pages it points to are assumed to stay alive
  * for as long as this mapping might exist.
  */
-int install_special_mapping(struct mm_struct *mm,
+struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
 			    unsigned long addr, unsigned long len,
 			    unsigned long vm_flags, struct page **pages)
 {
@@ -2927,7 +2927,7 @@ int install_special_mapping(struct mm_struct *mm,
 
 	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 	if (unlikely(vma == NULL))
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&vma->anon_vma_chain);
 	vma->vm_mm = mm;
@@ -2948,11 +2948,23 @@ int install_special_mapping(struct mm_struct *mm,
 
 	perf_event_mmap(vma);
 
-	return 0;
+	return vma;
 
 out:
 	kmem_cache_free(vm_area_cachep, vma);
-	return ret;
+	return ERR_PTR(ret);
+}
+
+int install_special_mapping(struct mm_struct *mm,
+			    unsigned long addr, unsigned long len,
+			    unsigned long vm_flags, struct page **pages)
+{
+	struct vm_area_struct *vma = _install_special_mapping(mm,
+			    addr, len, vm_flags, pages);
+
+	if (IS_ERR(vma))
+		return PTR_ERR(vma);
+	return 0;
 }
 
 static DEFINE_MUTEX(mm_all_locks_mutex);

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Revamp vclock_gettime.c
  2014-03-17 22:22 ` [PATCH v23 03/13] x86, vdso: Revamp vclock_gettime.c Stefani Seibold
@ 2014-03-18 21:28   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:28 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  411f790cd7e91fac0db80d3cf789cb6deeac298e
Gitweb:     http://git.kernel.org/tip/411f790cd7e91fac0db80d3cf789cb6deeac298e
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:03 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:51:59 -0700

x86, vdso: Revamp vclock_gettime.c

This intermediate patch revamps the vclock_gettime.c by moving some functions
around. It is only for spliting purpose, to make whole the 32 bit vdso timer
patch easier to review.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-4-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/vdso/vclock_gettime.c | 85 +++++++++++++++++++++---------------------
 1 file changed, 42 insertions(+), 43 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index eb5d7a5..bbc8065 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -26,41 +26,26 @@
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
-notrace static cycle_t vread_tsc(void)
+static notrace cycle_t vread_hpet(void)
 {
-	cycle_t ret;
-	u64 last;
-
-	/*
-	 * Empirically, a fence (of type that depends on the CPU)
-	 * before rdtsc is enough to ensure that rdtsc is ordered
-	 * with respect to loads.  The various CPU manuals are unclear
-	 * as to whether rdtsc can be reordered with later loads,
-	 * but no one has ever seen it happen.
-	 */
-	rdtsc_barrier();
-	ret = (cycle_t)vget_cycles();
-
-	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
-
-	if (likely(ret >= last))
-		return ret;
+	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+}
 
-	/*
-	 * GCC likes to generate cmov here, but this branch is extremely
-	 * predictable (it's just a funciton of time and the likely is
-	 * very likely) and there's a data dependence, so force GCC
-	 * to generate a branch instead.  I don't barrier() because
-	 * we don't actually need a barrier, and if this function
-	 * ever gets inlined it will generate worse code.
-	 */
-	asm volatile ("");
-	return last;
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+{
+	long ret;
+	asm("syscall" : "=a" (ret) :
+	    "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
+	return ret;
 }
 
-static notrace cycle_t vread_hpet(void)
+notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
 {
-	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+	long ret;
+
+	asm("syscall" : "=a" (ret) :
+	    "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
+	return ret;
 }
 
 #ifdef CONFIG_PARAVIRT_CLOCK
@@ -133,23 +118,37 @@ static notrace cycle_t vread_pvclock(int *mode)
 }
 #endif
 
-notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+notrace static cycle_t vread_tsc(void)
 {
-	long ret;
-	asm("syscall" : "=a" (ret) :
-	    "0" (__NR_clock_gettime),"D" (clock), "S" (ts) : "memory");
-	return ret;
-}
+	cycle_t ret;
+	u64 last;
 
-notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
-{
-	long ret;
+	/*
+	 * Empirically, a fence (of type that depends on the CPU)
+	 * before rdtsc is enough to ensure that rdtsc is ordered
+	 * with respect to loads.  The various CPU manuals are unclear
+	 * as to whether rdtsc can be reordered with later loads,
+	 * but no one has ever seen it happen.
+	 */
+	rdtsc_barrier();
+	ret = (cycle_t)vget_cycles();
 
-	asm("syscall" : "=a" (ret) :
-	    "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
-	return ret;
-}
+	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
 
+	if (likely(ret >= last))
+		return ret;
+
+	/*
+	 * GCC likes to generate cmov here, but this branch is extremely
+	 * predictable (it's just a funciton of time and the likely is
+	 * very likely) and there's a data dependence, so force GCC
+	 * to generate a branch instead.  I don't barrier() because
+	 * we don't actually need a barrier, and if this function
+	 * ever gets inlined it will generate worse code.
+	 */
+	asm volatile ("");
+	return last;
+}
 
 notrace static inline u64 vgetsns(int *mode)
 {

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: __vdso_clock_gettime() cleanup
  2014-03-17 22:22 ` [PATCH v23 04/13] x86, vdso: __vdso_clock_gettime() cleanup Stefani Seibold
@ 2014-03-18 21:28   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:28 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  ce39c64028a075d14af32bfb8336bfe1370c0443
Gitweb:     http://git.kernel.org/tip/ce39c64028a075d14af32bfb8336bfe1370c0443
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:04 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:01 -0700

x86, vdso: __vdso_clock_gettime() cleanup

This patch is a small code cleanup for the __vdso_clock_gettime() function.

It removes the unneeded return values from do_monotonic_coarse() and
do_realtime_coarse() and add a fallback label for doing the kernel
gettimeofday() system call.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-5-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/vdso/vclock_gettime.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index bbc8065..fd074dd 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -209,7 +209,7 @@ notrace static int do_monotonic(struct timespec *ts)
 	return mode;
 }
 
-notrace static int do_realtime_coarse(struct timespec *ts)
+notrace static void do_realtime_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
@@ -217,10 +217,9 @@ notrace static int do_realtime_coarse(struct timespec *ts)
 		ts->tv_sec = gtod->wall_time_coarse.tv_sec;
 		ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
 	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-	return 0;
 }
 
-notrace static int do_monotonic_coarse(struct timespec *ts)
+notrace static void do_monotonic_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
@@ -228,30 +227,32 @@ notrace static int do_monotonic_coarse(struct timespec *ts)
 		ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
 		ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
 	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-
-	return 0;
 }
 
 notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
 {
-	int ret = VCLOCK_NONE;
-
 	switch (clock) {
 	case CLOCK_REALTIME:
-		ret = do_realtime(ts);
+		if (do_realtime(ts) == VCLOCK_NONE)
+			goto fallback;
 		break;
 	case CLOCK_MONOTONIC:
-		ret = do_monotonic(ts);
+		if (do_monotonic(ts) == VCLOCK_NONE)
+			goto fallback;
 		break;
 	case CLOCK_REALTIME_COARSE:
-		return do_realtime_coarse(ts);
+		do_realtime_coarse(ts);
+		break;
 	case CLOCK_MONOTONIC_COARSE:
-		return do_monotonic_coarse(ts);
+		do_monotonic_coarse(ts);
+		break;
+	default:
+		goto fallback;
 	}
 
-	if (ret == VCLOCK_NONE)
-		return vdso_fallback_gettime(clock, ts);
 	return 0;
+fallback:
+	return vdso_fallback_gettime(clock, ts);
 }
 int clock_gettime(clockid_t, struct timespec *)
 	__attribute__((weak, alias("__vdso_clock_gettime")));

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro
  2014-03-17 22:22 ` [PATCH v23 05/13] x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro Stefani Seibold
@ 2014-03-18 21:28   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:28 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  af8c93d8d9809c3cf71cae2c398069399e64efa3
Gitweb:     http://git.kernel.org/tip/af8c93d8d9809c3cf71cae2c398069399e64efa3
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:05 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:03 -0700

x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro

There a currently more than 30 users of the gtod macro, so replace the
last VVAR(vsyscall_gtod_data) by gtod macro.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-6-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/vdso/vclock_gettime.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index fd074dd..743f277 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -109,7 +109,7 @@ static notrace cycle_t vread_pvclock(int *mode)
 		*mode = VCLOCK_NONE;
 
 	/* refer to tsc.c read_tsc() comment for rationale */
-	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
+	last = gtod->clock.cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -133,7 +133,7 @@ notrace static cycle_t vread_tsc(void)
 	rdtsc_barrier();
 	ret = (cycle_t)vget_cycles();
 
-	last = VVAR(vsyscall_gtod_data).clock.cycle_last;
+	last = gtod->clock.cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -288,7 +288,7 @@ int gettimeofday(struct timeval *, struct timezone *)
 notrace time_t __vdso_time(time_t *t)
 {
 	/* This is atomic on x86_64 so we don't need any locks. */
-	time_t result = ACCESS_ONCE(VVAR(vsyscall_gtod_data).wall_time_sec);
+	time_t result = ACCESS_ONCE(gtod->wall_time_sec);
 
 	if (t)
 		*t = result;

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Cleanup __vdso_gettimeofday()
  2014-03-17 22:22 ` [PATCH v23 06/13] x86, vdso: Cleanup __vdso_gettimeofday() Stefani Seibold
@ 2014-03-18 21:28   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:28 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  0df1ea2b7955d3cb311a549c44ed482452b859ff
Gitweb:     http://git.kernel.org/tip/0df1ea2b7955d3cb311a549c44ed482452b859ff
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:06 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:26 -0700

x86, vdso: Cleanup __vdso_gettimeofday()

This patch cleans up the __vdso_gettimeofday() function a little.

It kicks out an unneeded ret local variable and makes the code faster
if only the timezone is needed (an admittedly rare case.)

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-7-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/vdso/vclock_gettime.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 743f277..09dae4a 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -259,13 +259,12 @@ int clock_gettime(clockid_t, struct timespec *)
 
 notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
-	long ret = VCLOCK_NONE;
-
 	if (likely(tv != NULL)) {
 		BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
 			     offsetof(struct timespec, tv_nsec) ||
 			     sizeof(*tv) != sizeof(struct timespec));
-		ret = do_realtime((struct timespec *)tv);
+		if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
+			return vdso_fallback_gtod(tv, tz);
 		tv->tv_usec /= 1000;
 	}
 	if (unlikely(tz != NULL)) {
@@ -274,8 +273,6 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 		tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
 	}
 
-	if (ret == VCLOCK_NONE)
-		return vdso_fallback_gtod(tv, tz);
 	return 0;
 }
 int gettimeofday(struct timeval *, struct timezone *)

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Introduce VVAR marco for vdso32
  2014-03-17 22:22 ` [PATCH v23 07/13] x86, vdso: Introduce VVAR marco for vdso32 Stefani Seibold
@ 2014-03-18 21:29   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:29 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  ef721987aef0cc0abba08c88810f2155f76b0b1f
Gitweb:     http://git.kernel.org/tip/ef721987aef0cc0abba08c88810f2155f76b0b1f
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:07 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:29 -0700

x86, vdso: Introduce VVAR marco for vdso32

This patch revamps the vvar.h for introduce the VVAR macro for vdso32.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-8-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/vvar.h | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 0a534ea..52c79ff 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -26,6 +26,15 @@
 
 #else
 
+#ifdef BUILD_VDSO32
+
+#define DECLARE_VVAR(offset, type, name)				\
+	extern type vvar_ ## name __attribute__((visibility("hidden")));
+
+#define VVAR(name) (vvar_ ## name)
+
+#else
+
 extern char __vvar_page;
 
 /* Base address of vvars.  This is not ABI. */
@@ -39,12 +48,13 @@ extern char __vvar_page;
 	static type const * const vvaraddr_ ## name =			\
 		(void *)(VVAR_ADDRESS + (offset));
 
+#define VVAR(name) (*vvaraddr_ ## name)
+#endif
+
 #define DEFINE_VVAR(type, name)						\
 	type name							\
 	__attribute__((section(".vvar_" #name), aligned(16))) __visible
 
-#define VVAR(name) (*vvaraddr_ ## name)
-
 #endif
 
 /* DECLARE_VVAR(offset, type, name) */

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Patch alternatives in the 32-bit VDSO
  2014-03-17 22:22 ` [PATCH v23 08/13] x86, vdso: Patch alternatives in the 32-bit VDSO Stefani Seibold
@ 2014-03-18 21:29   ` tip-bot for Andy Lutomirski
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Andy Lutomirski @ 2014-03-18 21:29 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  b4b541a610c4db8643b36030ee5012203ca65778
Gitweb:     http://git.kernel.org/tip/b4b541a610c4db8643b36030ee5012203ca65778
Author:     Andy Lutomirski <luto@amacapital.net>
AuthorDate: Mon, 17 Mar 2014 23:22:08 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:33 -0700

x86, vdso: Patch alternatives in the 32-bit VDSO

We need the alternatives mechanism for rdtsc_barrier() to work.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-9-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/vdso.h  |  2 ++
 arch/x86/vdso/Makefile       |  3 ++-
 arch/x86/vdso/vdso32-setup.c | 23 ++++++++++++-----------
 arch/x86/vdso/vma.c          | 13 ++++++++++---
 4 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 5594e84..f8605e6 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -28,4 +28,6 @@ extern const char vdso32_int80_start, vdso32_int80_end;
 extern const char vdso32_syscall_start, vdso32_syscall_end;
 extern const char vdso32_sysenter_start, vdso32_sysenter_end;
 
+void __init patch_vdso32(void *vdso, size_t len);
+
 #endif /* _ASM_X86_VDSO_H */
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index fd14be1..7a3d13e 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -21,7 +21,8 @@ vobjs-$(VDSOX32-y) += $(vobjx32s-compat)
 vobj64s := $(filter-out $(vobjx32s-compat),$(vobjs-y))
 
 # files to link into kernel
-obj-$(VDSO64-y)			+= vma.o vdso.o
+obj-y				+= vma.o
+obj-$(VDSO64-y)			+= vdso.o
 obj-$(VDSOX32-y)		+= vdsox32.o
 obj-$(VDSO32-y)			+= vdso32.o vdso32-setup.o
 
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index ab20c04..e0fc767 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -112,24 +112,25 @@ void enable_sep_cpu(void)
 
 int __init sysenter_setup(void)
 {
-	void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
-	const void *vsyscall;
-	size_t vsyscall_len;
+	void *vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
+	const void *vdso;
+	size_t vdso_len;
 
-	vdso32_pages[0] = virt_to_page(syscall_page);
+	vdso32_pages[0] = virt_to_page(vdso_page);
 
 	if (vdso32_syscall()) {
-		vsyscall = &vdso32_syscall_start;
-		vsyscall_len = &vdso32_syscall_end - &vdso32_syscall_start;
+		vdso = &vdso32_syscall_start;
+		vdso_len = &vdso32_syscall_end - &vdso32_syscall_start;
 	} else if (vdso32_sysenter()){
-		vsyscall = &vdso32_sysenter_start;
-		vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
+		vdso = &vdso32_sysenter_start;
+		vdso_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
 	} else {
-		vsyscall = &vdso32_int80_start;
-		vsyscall_len = &vdso32_int80_end - &vdso32_int80_start;
+		vdso = &vdso32_int80_start;
+		vdso_len = &vdso32_int80_end - &vdso32_int80_start;
 	}
 
-	memcpy(syscall_page, vsyscall, vsyscall_len);
+	memcpy(vdso_page, vdso, vdso_len);
+	patch_vdso32(vdso_page, vdso_len);
 
 	return 0;
 }
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 431e875..7345bc9 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -16,6 +16,7 @@
 #include <asm/vdso.h>
 #include <asm/page.h>
 
+#if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso_enabled = 1;
 
 extern char vdso_start[], vdso_end[];
@@ -28,8 +29,12 @@ static unsigned vdso_size;
 extern char vdsox32_start[], vdsox32_end[];
 extern struct page *vdsox32_pages[];
 static unsigned vdsox32_size;
+#endif
+#endif
 
-static void __init patch_vdsox32(void *vdso, size_t len)
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_X32_ABI) || \
+	defined(CONFIG_COMPAT)
+void __init patch_vdso32(void *vdso, size_t len)
 {
 	Elf32_Ehdr *hdr = vdso;
 	Elf32_Shdr *sechdrs, *alt_sec = 0;
@@ -52,7 +57,7 @@ static void __init patch_vdsox32(void *vdso, size_t len)
 	}
 
 	/* If we get here, it's probably a bug. */
-	pr_warning("patch_vdsox32: .altinstructions not found\n");
+	pr_warning("patch_vdso32: .altinstructions not found\n");
 	return;  /* nothing to patch */
 
 found:
@@ -61,6 +66,7 @@ found:
 }
 #endif
 
+#if defined(CONFIG_X86_64)
 static void __init patch_vdso64(void *vdso, size_t len)
 {
 	Elf64_Ehdr *hdr = vdso;
@@ -104,7 +110,7 @@ static int __init init_vdso(void)
 		vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE);
 
 #ifdef CONFIG_X86_X32_ABI
-	patch_vdsox32(vdsox32_start, vdsox32_end - vdsox32_start);
+	patch_vdso32(vdsox32_start, vdsox32_end - vdsox32_start);
 	npages = (vdsox32_end - vdsox32_start + PAGE_SIZE - 1) / PAGE_SIZE;
 	vdsox32_size = npages << PAGE_SHIFT;
 	for (i = 0; i < npages; i++)
@@ -204,3 +210,4 @@ static __init int vdso_setup(char *s)
 	return 0;
 }
 __setup("vdso=", vdso_setup);
+#endif

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Add 32 bit VDSO time support for 32 bit kernel
  2014-03-17 22:22 ` [PATCH v23 09/13] x86, vdso: Add 32 bit VDSO time support for 32 bit kernel Stefani Seibold
@ 2014-03-18 21:29   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:29 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  7a59ed415f5b57469e22e41fc4188d5399e0b194
Gitweb:     http://git.kernel.org/tip/7a59ed415f5b57469e22e41fc4188d5399e0b194
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:09 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:37 -0700

x86, vdso: Add 32 bit VDSO time support for 32 bit kernel

This patch add the time support for 32 bit a VDSO to a 32 bit kernel.

For 32 bit programs running on a 32 bit kernel, the same mechanism is
used as for 64 bit programs running on a 64 bit kernel.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-10-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/vdso.h           |  5 +++
 arch/x86/include/asm/vdso32.h         | 11 +++++
 arch/x86/vdso/Makefile                |  8 ++++
 arch/x86/vdso/vclock_gettime.c        | 76 +++++++++++++++++++++++++++++++----
 arch/x86/vdso/vdso-layout.lds.S       | 22 ++++++++++
 arch/x86/vdso/vdso32-setup.c          | 47 ++++++++++++++++++++--
 arch/x86/vdso/vdso32/vclock_gettime.c |  9 +++++
 arch/x86/vdso/vdso32/vdso32.lds.S     | 11 +++++
 8 files changed, 178 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index f8605e6..bde4359 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -2,6 +2,11 @@
 #define _ASM_X86_VDSO_H
 
 #if defined CONFIG_X86_32 || defined CONFIG_COMPAT
+
+#include <asm/vdso32.h>
+
+extern const char VDSO32_PRELINK[];
+
 /*
  * Given a pointer to the vDSO image, find the pointer to VDSO32_name
  * as that symbol is defined in the vDSO sources or linker script.
diff --git a/arch/x86/include/asm/vdso32.h b/arch/x86/include/asm/vdso32.h
new file mode 100644
index 0000000..7efb701
--- /dev/null
+++ b/arch/x86/include/asm/vdso32.h
@@ -0,0 +1,11 @@
+#ifndef _ASM_X86_VDSO32_H
+#define _ASM_X86_VDSO32_H
+
+#define VDSO_BASE_PAGE	0
+#define VDSO_VVAR_PAGE	1
+#define VDSO_HPET_PAGE	2
+#define VDSO_PAGES	3
+#define VDSO_PREV_PAGES	2
+#define VDSO_OFFSET(x)	((x) * PAGE_SIZE)
+
+#endif
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 7a3d13e..6cef7a1 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -146,8 +146,16 @@ KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
 $(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
 $(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
 
+KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
+KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
+$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
+
 $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
 				 $(obj)/vdso32/vdso32.lds \
+				 $(obj)/vdso32/vclock_gettime.o \
 				 $(obj)/vdso32/note.o \
 				 $(obj)/vdso32/%.o
 	$(call if_changed,vdso)
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 09dae4a..90bb5e8 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -4,6 +4,9 @@
  *
  * Fast user context implementation of clock_gettime, gettimeofday, and time.
  *
+ * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
+ *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
+ *
  * The code should have no internal unresolved relocations.
  * Check with readelf after changing.
  */
@@ -12,13 +15,11 @@
 #define DISABLE_BRANCH_PROFILING
 
 #include <linux/kernel.h>
-#include <linux/posix-timers.h>
-#include <linux/time.h>
+#include <uapi/linux/time.h>
 #include <linux/string.h>
 #include <asm/vsyscall.h>
 #include <asm/fixmap.h>
 #include <asm/vgtod.h>
-#include <asm/timex.h>
 #include <asm/hpet.h>
 #include <asm/unistd.h>
 #include <asm/io.h>
@@ -26,6 +27,12 @@
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
+extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
+extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
+extern time_t __vdso_time(time_t *t);
+
+#ifndef BUILD_VDSO32
+
 static notrace cycle_t vread_hpet(void)
 {
 	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
@@ -118,6 +125,59 @@ static notrace cycle_t vread_pvclock(int *mode)
 }
 #endif
 
+#else
+
+extern u8 hpet_page
+	__attribute__((visibility("hidden")));
+
+#ifdef CONFIG_HPET_TIMER
+static notrace cycle_t vread_hpet(void)
+{
+	return readl((const void __iomem *)(&hpet_page + HPET_COUNTER));
+}
+#endif
+
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+{
+	long ret;
+
+	asm(
+		"mov %%ebx, %%edx \n"
+		"mov %2, %%ebx \n"
+		"call VDSO32_vsyscall \n"
+		"mov %%edx, %%ebx \n"
+		: "=a" (ret)
+		: "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
+		: "memory", "edx");
+	return ret;
+}
+
+notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
+{
+	long ret;
+
+	asm(
+		"mov %%ebx, %%edx \n"
+		"mov %2, %%ebx \n"
+		"call VDSO32_vsyscall \n"
+		"mov %%edx, %%ebx \n"
+		: "=a" (ret)
+		: "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
+		: "memory", "edx");
+	return ret;
+}
+
+#ifdef CONFIG_PARAVIRT_CLOCK
+
+static notrace cycle_t vread_pvclock(int *mode)
+{
+	*mode = VCLOCK_NONE;
+	return 0;
+}
+#endif
+
+#endif
+
 notrace static cycle_t vread_tsc(void)
 {
 	cycle_t ret;
@@ -131,7 +191,7 @@ notrace static cycle_t vread_tsc(void)
 	 * but no one has ever seen it happen.
 	 */
 	rdtsc_barrier();
-	ret = (cycle_t)vget_cycles();
+	ret = (cycle_t)__native_read_tsc();
 
 	last = gtod->clock.cycle_last;
 
@@ -152,12 +212,14 @@ notrace static cycle_t vread_tsc(void)
 
 notrace static inline u64 vgetsns(int *mode)
 {
-	long v;
+	u64 v;
 	cycles_t cycles;
 	if (gtod->clock.vclock_mode == VCLOCK_TSC)
 		cycles = vread_tsc();
+#ifdef CONFIG_HPET_TIMER
 	else if (gtod->clock.vclock_mode == VCLOCK_HPET)
 		cycles = vread_hpet();
+#endif
 #ifdef CONFIG_PARAVIRT_CLOCK
 	else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
 		cycles = vread_pvclock(mode);
@@ -189,7 +251,7 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
 	return mode;
 }
 
-notrace static int do_monotonic(struct timespec *ts)
+notrace static int __always_inline do_monotonic(struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;
@@ -284,7 +346,7 @@ int gettimeofday(struct timeval *, struct timezone *)
  */
 notrace time_t __vdso_time(time_t *t)
 {
-	/* This is atomic on x86_64 so we don't need any locks. */
+	/* This is atomic on x86 so we don't need any locks. */
 	time_t result = ACCESS_ONCE(gtod->wall_time_sec);
 
 	if (t)
diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S
index 8c550c1..c6d0e1b 100644
--- a/arch/x86/vdso/vdso-layout.lds.S
+++ b/arch/x86/vdso/vdso-layout.lds.S
@@ -6,6 +6,24 @@
 
 SECTIONS
 {
+#ifdef BUILD_VDSO32
+#include <asm/vdso32.h>
+
+	.hpet_sect : {
+		hpet_page = . - VDSO_OFFSET(VDSO_HPET_PAGE);
+	} :text :hpet_sect
+
+	.vvar_sect : {
+		vvar = . - VDSO_OFFSET(VDSO_VVAR_PAGE);
+
+	/* Place all vvars at the offsets in asm/vvar.h. */
+#define EMIT_VVAR(name, offset) vvar_ ## name = vvar + offset;
+#define __VVAR_KERNEL_LDS
+#include <asm/vvar.h>
+#undef __VVAR_KERNEL_LDS
+#undef EMIT_VVAR
+	} :text :vvar_sect
+#endif
 	. = SIZEOF_HEADERS;
 
 	.hash		: { *(.hash) }			:text
@@ -61,4 +79,8 @@ PHDRS
 	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
 	note		PT_NOTE		FLAGS(4);		/* PF_R */
 	eh_frame_hdr	PT_GNU_EH_FRAME;
+#ifdef BUILD_VDSO32
+	vvar_sect	PT_NULL		FLAGS(4);		/* PF_R */
+	hpet_sect	PT_NULL		FLAGS(4);		/* PF_R */
+#endif
 }
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e0fc767..e10abdf 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -25,6 +25,9 @@
 #include <asm/tlbflush.h>
 #include <asm/vdso.h>
 #include <asm/proto.h>
+#include <asm/fixmap.h>
+#include <asm/hpet.h>
+#include <asm/vvar.h>
 
 #ifdef CONFIG_COMPAT_VDSO
 #define VDSO_DEFAULT	0
@@ -141,6 +144,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	struct mm_struct *mm = current->mm;
 	unsigned long addr;
 	int ret = 0;
+	struct vm_area_struct *vma;
 
 #ifdef CONFIG_X86_X32_ABI
 	if (test_thread_flag(TIF_X32))
@@ -163,14 +167,49 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	/*
 	 * MAYWRITE to allow gdb to COW and set breakpoints
 	 */
-	ret = install_special_mapping(mm, addr, PAGE_SIZE,
-				      VM_READ|VM_EXEC|
-				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				      vdso32_pages);
+	ret = install_special_mapping(mm,
+			addr,
+			VDSO_OFFSET(VDSO_PAGES - VDSO_PREV_PAGES),
+			VM_READ|VM_EXEC|
+			VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+			vdso32_pages);
 
 	if (ret)
 		goto up_fail;
 
+	vma = _install_special_mapping(mm,
+			addr -  VDSO_OFFSET(VDSO_PREV_PAGES),
+			VDSO_OFFSET(VDSO_PREV_PAGES),
+			VM_READ,
+			NULL);
+
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto up_fail;
+	}
+
+	ret = remap_pfn_range(vma,
+		addr - VDSO_OFFSET(VDSO_VVAR_PAGE),
+		__pa_symbol(&__vvar_page) >> PAGE_SHIFT,
+		PAGE_SIZE,
+		PAGE_READONLY);
+
+	if (ret)
+		goto up_fail;
+
+#ifdef CONFIG_HPET_TIMER
+	if (hpet_address) {
+		ret = io_remap_pfn_range(vma,
+			addr - VDSO_OFFSET(VDSO_HPET_PAGE),
+			hpet_address >> PAGE_SHIFT,
+			PAGE_SIZE,
+			pgprot_noncached(PAGE_READONLY));
+
+		if (ret)
+			goto up_fail;
+	}
+#endif
+
 	current_thread_info()->sysenter_return =
 		VDSO32_SYMBOL(addr, SYSENTER_RETURN);
 
diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c b/arch/x86/vdso/vdso32/vclock_gettime.c
new file mode 100644
index 0000000..ca65e42
--- /dev/null
+++ b/arch/x86/vdso/vdso32/vclock_gettime.c
@@ -0,0 +1,9 @@
+#define BUILD_VDSO32
+
+#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
+#undef CONFIG_OPTIMIZE_INLINING
+#endif
+
+#undef CONFIG_X86_PPRO_FENCE
+
+#include "../vclock_gettime.c"
diff --git a/arch/x86/vdso/vdso32/vdso32.lds.S b/arch/x86/vdso/vdso32/vdso32.lds.S
index 90e7aa9..28c4607 100644
--- a/arch/x86/vdso/vdso32/vdso32.lds.S
+++ b/arch/x86/vdso/vdso32/vdso32.lds.S
@@ -8,6 +8,11 @@
  * values visible using the asm-x86/vdso.h macros from the kernel proper.
  */
 
+#include <asm/page.h>
+
+#define BUILD_VDSO32
+#define VDSO_PRELINK 0
+
 #include "../vdso-layout.lds.S"
 
 /* The ELF entry point can be used to set the AT_SYSINFO value.  */
@@ -23,6 +28,9 @@ VERSION
 		__kernel_vsyscall;
 		__kernel_sigreturn;
 		__kernel_rt_sigreturn;
+		__vdso_clock_gettime;
+		__vdso_gettimeofday;
+		__vdso_time;
 	local: *;
 	};
 }
@@ -33,3 +41,6 @@ VERSION
 VDSO32_vsyscall		= __kernel_vsyscall;
 VDSO32_sigreturn	= __kernel_sigreturn;
 VDSO32_rt_sigreturn	= __kernel_rt_sigreturn;
+VDSO32_clock_gettime	= clock_gettime;
+VDSO32_gettimeofday	= gettimeofday;
+VDSO32_time		= time;

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
  2014-03-17 22:22 ` [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 " Stefani Seibold
@ 2014-03-18 21:29   ` tip-bot for Stefani Seibold
  2014-03-27 20:44   ` [PATCH v23 10/13] " John Stultz
  1 sibling, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:29 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, stefani, tglx, hpa

Commit-ID:  7c03156f34d113f885f045d8fb8cc3efd9e64751
Gitweb:     http://git.kernel.org/tip/7c03156f34d113f885f045d8fb8cc3efd9e64751
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:10 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:41 -0700

x86, vdso: Add 32 bit VDSO time support for 64 bit kernel

This patch add the VDSO time support for the IA32 Emulation Layer.

Due the nature of the kernel headers and the LP64 compiler where the
size of a long and a pointer differs against a 32 bit compiler, there
is some type hacking necessary for optimal performance.

The vsyscall_gtod_data struture must be a rearranged to serve 32- and
64-bit code access at the same time:

- The seqcount_t was replaced by an unsigned, this makes the
  vsyscall_gtod_data intedepend of kernel configuration and internal functions.
- All kernel internal structures are replaced by fix size elements
  which works for 32- and 64-bit access
- The inner struct clock was removed to pack the whole struct.

The "unsigned seq" would be handled by functions derivated from seqcount_t.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-11-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/vgtod.h          | 71 +++++++++++++++++++++------
 arch/x86/include/asm/vvar.h           |  5 ++
 arch/x86/kernel/vsyscall_gtod.c       | 34 ++++++++-----
 arch/x86/vdso/vclock_gettime.c        | 91 +++++++++++++++++++----------------
 arch/x86/vdso/vdso32/vclock_gettime.c | 21 ++++++++
 5 files changed, 155 insertions(+), 67 deletions(-)

diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index 46e24d3..3c3366c 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -1,30 +1,73 @@
 #ifndef _ASM_X86_VGTOD_H
 #define _ASM_X86_VGTOD_H
 
-#include <asm/vsyscall.h>
+#include <linux/compiler.h>
 #include <linux/clocksource.h>
 
+#ifdef BUILD_VDSO32_64
+typedef u64 gtod_long_t;
+#else
+typedef unsigned long gtod_long_t;
+#endif
+/*
+ * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
+ * so be carefull by modifying this structure.
+ */
 struct vsyscall_gtod_data {
-	seqcount_t	seq;
+	unsigned seq;
 
-	struct { /* extract of a clocksource struct */
-		int vclock_mode;
-		cycle_t	cycle_last;
-		cycle_t	mask;
-		u32	mult;
-		u32	shift;
-	} clock;
+	int vclock_mode;
+	cycle_t	cycle_last;
+	cycle_t	mask;
+	u32	mult;
+	u32	shift;
 
 	/* open coded 'struct timespec' */
-	time_t		wall_time_sec;
 	u64		wall_time_snsec;
+	gtod_long_t	wall_time_sec;
+	gtod_long_t	monotonic_time_sec;
 	u64		monotonic_time_snsec;
-	time_t		monotonic_time_sec;
+	gtod_long_t	wall_time_coarse_sec;
+	gtod_long_t	wall_time_coarse_nsec;
+	gtod_long_t	monotonic_time_coarse_sec;
+	gtod_long_t	monotonic_time_coarse_nsec;
 
-	struct timezone sys_tz;
-	struct timespec wall_time_coarse;
-	struct timespec monotonic_time_coarse;
+	int		tz_minuteswest;
+	int		tz_dsttime;
 };
 extern struct vsyscall_gtod_data vsyscall_gtod_data;
 
+static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
+{
+	unsigned ret;
+
+repeat:
+	ret = ACCESS_ONCE(s->seq);
+	if (unlikely(ret & 1)) {
+		cpu_relax();
+		goto repeat;
+	}
+	smp_rmb();
+	return ret;
+}
+
+static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
+					unsigned start)
+{
+	smp_rmb();
+	return unlikely(s->seq != start);
+}
+
+static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
+{
+	++s->seq;
+	smp_wmb();
+}
+
+static inline void gtod_write_end(struct vsyscall_gtod_data *s)
+{
+	smp_wmb();
+	++s->seq;
+}
+
 #endif /* _ASM_X86_VGTOD_H */
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 52c79ff..081d909 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -16,6 +16,9 @@
  * you mess up, the linker will catch it.)
  */
 
+#ifndef _ASM_X86_VVAR_H
+#define _ASM_X86_VVAR_H
+
 #if defined(__VVAR_KERNEL_LDS)
 
 /* The kernel linker script defines its own magic to put vvars in the
@@ -64,3 +67,5 @@ DECLARE_VVAR(16, int, vgetcpu_mode)
 DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data)
 
 #undef DECLARE_VVAR
+
+#endif
diff --git a/arch/x86/kernel/vsyscall_gtod.c b/arch/x86/kernel/vsyscall_gtod.c
index b5a943d..f9c6e56 100644
--- a/arch/x86/kernel/vsyscall_gtod.c
+++ b/arch/x86/kernel/vsyscall_gtod.c
@@ -4,6 +4,7 @@
  *
  *  Modified for x86 32 bit architecture by
  *  Stefani Seibold <stefani@seibold.net>
+ *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
  *
  *  Thanks to hpa@transmeta.com for some useful hint.
  *  Special thanks to Ingo Molnar for his early experience with
@@ -13,26 +14,28 @@
 
 #include <linux/timekeeper_internal.h>
 #include <asm/vgtod.h>
+#include <asm/vvar.h>
 
 DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
 
 void update_vsyscall_tz(void)
 {
-	vsyscall_gtod_data.sys_tz = sys_tz;
+	vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest;
+	vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime;
 }
 
 void update_vsyscall(struct timekeeper *tk)
 {
 	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
 
-	write_seqcount_begin(&vdata->seq);
+	gtod_write_begin(vdata);
 
 	/* copy vsyscall data */
-	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;
-	vdata->clock.cycle_last		= tk->clock->cycle_last;
-	vdata->clock.mask		= tk->clock->mask;
-	vdata->clock.mult		= tk->mult;
-	vdata->clock.shift		= tk->shift;
+	vdata->vclock_mode	= tk->clock->archdata.vclock_mode;
+	vdata->cycle_last	= tk->clock->cycle_last;
+	vdata->mask		= tk->clock->mask;
+	vdata->mult		= tk->mult;
+	vdata->shift		= tk->shift;
 
 	vdata->wall_time_sec		= tk->xtime_sec;
 	vdata->wall_time_snsec		= tk->xtime_nsec;
@@ -49,11 +52,18 @@ void update_vsyscall(struct timekeeper *tk)
 		vdata->monotonic_time_sec++;
 	}
 
-	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;
-	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);
+	vdata->wall_time_coarse_sec	= tk->xtime_sec;
+	vdata->wall_time_coarse_nsec	= (long)(tk->xtime_nsec >> tk->shift);
 
-	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,
-							tk->wall_to_monotonic);
+	vdata->monotonic_time_coarse_sec =
+		vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec;
+	vdata->monotonic_time_coarse_nsec =
+		vdata->wall_time_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
 
-	write_seqcount_end(&vdata->seq);
+	while (vdata->monotonic_time_coarse_nsec >= NSEC_PER_SEC) {
+		vdata->monotonic_time_coarse_nsec -= NSEC_PER_SEC;
+		vdata->monotonic_time_coarse_sec++;
+	}
+
+	gtod_write_end(vdata);
 }
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 90bb5e8..16d6861 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -14,16 +14,14 @@
 /* Disable profiling for userspace code: */
 #define DISABLE_BRANCH_PROFILING
 
-#include <linux/kernel.h>
 #include <uapi/linux/time.h>
-#include <linux/string.h>
-#include <asm/vsyscall.h>
-#include <asm/fixmap.h>
 #include <asm/vgtod.h>
 #include <asm/hpet.h>
+#include <asm/vvar.h>
 #include <asm/unistd.h>
-#include <asm/io.h>
-#include <asm/pvclock.h>
+#include <asm/msr.h>
+#include <linux/math64.h>
+#include <linux/time.h>
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
@@ -31,11 +29,23 @@ extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
 extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
 extern time_t __vdso_time(time_t *t);
 
+#ifdef CONFIG_HPET_TIMER
+static inline u32 read_hpet_counter(const volatile void *addr)
+{
+	return *(const volatile u32 *) (addr + HPET_COUNTER);
+}
+#endif
+
 #ifndef BUILD_VDSO32
 
+#include <linux/kernel.h>
+#include <asm/vsyscall.h>
+#include <asm/fixmap.h>
+#include <asm/pvclock.h>
+
 static notrace cycle_t vread_hpet(void)
 {
-	return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+	return read_hpet_counter((const void *)fix_to_virt(VSYSCALL_HPET));
 }
 
 notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
@@ -116,7 +126,7 @@ static notrace cycle_t vread_pvclock(int *mode)
 		*mode = VCLOCK_NONE;
 
 	/* refer to tsc.c read_tsc() comment for rationale */
-	last = gtod->clock.cycle_last;
+	last = gtod->cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -133,7 +143,7 @@ extern u8 hpet_page
 #ifdef CONFIG_HPET_TIMER
 static notrace cycle_t vread_hpet(void)
 {
-	return readl((const void __iomem *)(&hpet_page + HPET_COUNTER));
+	return read_hpet_counter((const void *)(&hpet_page));
 }
 #endif
 
@@ -193,7 +203,7 @@ notrace static cycle_t vread_tsc(void)
 	rdtsc_barrier();
 	ret = (cycle_t)__native_read_tsc();
 
-	last = gtod->clock.cycle_last;
+	last = gtod->cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
@@ -214,20 +224,21 @@ notrace static inline u64 vgetsns(int *mode)
 {
 	u64 v;
 	cycles_t cycles;
-	if (gtod->clock.vclock_mode == VCLOCK_TSC)
+
+	if (gtod->vclock_mode == VCLOCK_TSC)
 		cycles = vread_tsc();
 #ifdef CONFIG_HPET_TIMER
-	else if (gtod->clock.vclock_mode == VCLOCK_HPET)
+	else if (gtod->vclock_mode == VCLOCK_HPET)
 		cycles = vread_hpet();
 #endif
 #ifdef CONFIG_PARAVIRT_CLOCK
-	else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
+	else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
 		cycles = vread_pvclock(mode);
 #endif
 	else
 		return 0;
-	v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask;
-	return v * gtod->clock.mult;
+	v = (cycles - gtod->cycle_last) & gtod->mask;
+	return v * gtod->mult;
 }
 
 /* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
@@ -237,17 +248,18 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
 	u64 ns;
 	int mode;
 
-	ts->tv_nsec = 0;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		mode = gtod->clock.vclock_mode;
+		seq = gtod_read_begin(gtod);
+		mode = gtod->vclock_mode;
 		ts->tv_sec = gtod->wall_time_sec;
 		ns = gtod->wall_time_snsec;
 		ns += vgetsns(&mode);
-		ns >>= gtod->clock.shift;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+		ns >>= gtod->shift;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
+
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
 
-	timespec_add_ns(ts, ns);
 	return mode;
 }
 
@@ -257,16 +269,17 @@ notrace static int __always_inline do_monotonic(struct timespec *ts)
 	u64 ns;
 	int mode;
 
-	ts->tv_nsec = 0;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		mode = gtod->clock.vclock_mode;
+		seq = gtod_read_begin(gtod);
+		mode = gtod->vclock_mode;
 		ts->tv_sec = gtod->monotonic_time_sec;
 		ns = gtod->monotonic_time_snsec;
 		ns += vgetsns(&mode);
-		ns >>= gtod->clock.shift;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-	timespec_add_ns(ts, ns);
+		ns >>= gtod->shift;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
+
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
 
 	return mode;
 }
@@ -275,20 +288,20 @@ notrace static void do_realtime_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		ts->tv_sec = gtod->wall_time_coarse.tv_sec;
-		ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+		seq = gtod_read_begin(gtod);
+		ts->tv_sec = gtod->wall_time_coarse_sec;
+		ts->tv_nsec = gtod->wall_time_coarse_nsec;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
 }
 
 notrace static void do_monotonic_coarse(struct timespec *ts)
 {
 	unsigned long seq;
 	do {
-		seq = raw_read_seqcount_begin(&gtod->seq);
-		ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
-		ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
-	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+		seq = gtod_read_begin(gtod);
+		ts->tv_sec = gtod->monotonic_time_coarse_sec;
+		ts->tv_nsec = gtod->monotonic_time_coarse_nsec;
+	} while (unlikely(gtod_read_retry(gtod, seq)));
 }
 
 notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
@@ -322,17 +335,13 @@ int clock_gettime(clockid_t, struct timespec *)
 notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	if (likely(tv != NULL)) {
-		BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
-			     offsetof(struct timespec, tv_nsec) ||
-			     sizeof(*tv) != sizeof(struct timespec));
 		if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
 			return vdso_fallback_gtod(tv, tz);
 		tv->tv_usec /= 1000;
 	}
 	if (unlikely(tz != NULL)) {
-		/* Avoid memcpy. Some old compilers fail to inline it */
-		tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;
-		tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
+		tz->tz_minuteswest = gtod->tz_minuteswest;
+		tz->tz_dsttime = gtod->tz_dsttime;
 	}
 
 	return 0;
diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c b/arch/x86/vdso/vdso32/vclock_gettime.c
index ca65e42..175cc72 100644
--- a/arch/x86/vdso/vdso32/vclock_gettime.c
+++ b/arch/x86/vdso/vdso32/vclock_gettime.c
@@ -6,4 +6,25 @@
 
 #undef CONFIG_X86_PPRO_FENCE
 
+#ifdef CONFIG_X86_64
+
+/*
+ * in case of a 32 bit VDSO for a 64 bit kernel fake a 32 bit kernel
+ * configuration
+ */
+#undef CONFIG_64BIT
+#undef CONFIG_X86_64
+#undef CONFIG_ILLEGAL_POINTER_VALUE
+#undef CONFIG_SPARSEMEM_VMEMMAP
+#undef CONFIG_NR_CPUS
+
+#define CONFIG_X86_32 1
+#define CONFIG_PAGE_OFFSET 0
+#define CONFIG_ILLEGAL_POINTER_VALUE 0
+#define CONFIG_NR_CPUS 1
+
+#define BUILD_VDSO32_64
+
+#endif
+
 #include "../vclock_gettime.c"

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso: Zero-pad the VVAR page
  2014-03-17 22:22 ` [PATCH v23 11/13] x86, vdso: Zero-pad the VVAR page Stefani Seibold
@ 2014-03-18 21:29   ` tip-bot for Andy Lutomirski
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Andy Lutomirski @ 2014-03-18 21:29 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, luto, hpa, mingo, stefani, tglx, hpa

Commit-ID:  309944be296efbb3ca4737d12ef49d2ba97cbecc
Gitweb:     http://git.kernel.org/tip/309944be296efbb3ca4737d12ef49d2ba97cbecc
Author:     Andy Lutomirski <luto@amacapital.net>
AuthorDate: Mon, 17 Mar 2014 23:22:11 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:44 -0700

x86, vdso: Zero-pad the VVAR page

By coincidence, the VVAR page is at the end of an ELF segment.  As a
result, if it ends up being a partial page, the kernel loader will
leave garbage behind at the end of the vvar page.  Zero-pad it to a
full page to fix this issue.

This has probably been broken since the VVAR page was introduced.
On QEMU, if you dump the run-time contents of the VVAR page, you can
find entertaining strings from seabios left behind.

It's remotely possible that this is a security bug -- conceivably
there's some BIOS out there that leaves something sensitive in the
few K of memory that is exposed to userspace.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-12-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/kernel/vmlinux.lds.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 1d4897b..49edf2d 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -164,6 +164,11 @@ SECTIONS
 #undef __VVAR_KERNEL_LDS
 #undef EMIT_VVAR
 
+		/*
+		 * Pad the rest of the page with zeros.  Otherwise the loader
+		 * can leave garbage here.
+		 */
+		. = __vvar_beginning_hack + PAGE_SIZE;
 	} :data
 
        . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso32: Disable stack protector, adjust optimizations
  2014-03-17 22:22 ` [PATCH v23 12/13] x86, vdso32: Disable stack protector, adjust optimizations Stefani Seibold
@ 2014-03-18 21:29   ` tip-bot for H. Peter Anvin
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for H. Peter Anvin @ 2014-03-18 21:29 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, stefani, tglx, hpa

Commit-ID:  008cc907de327d83a0be609cd495fccb0e5dfa4c
Gitweb:     http://git.kernel.org/tip/008cc907de327d83a0be609cd495fccb0e5dfa4c
Author:     H. Peter Anvin <hpa@linux.intel.com>
AuthorDate: Mon, 17 Mar 2014 23:22:12 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:48 -0700

x86, vdso32: Disable stack protector, adjust optimizations

For the 32-bit VDSO, match the 64-bit VDSO in:

1. Disable the stack protector.
2. Use -fno-omit-frame-pointer for user space debugging sanity.
3. Use -foptimize-sibling-calls like the 64-bit VDSO does.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-13-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/vdso/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 6cef7a1..a2de5fc 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -151,6 +151,9 @@ KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
+KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
+KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
+KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 
 $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [tip:x86/vdso] x86, vdso32: handle 32 bit vDSO larger one page
  2014-03-17 22:22 ` [PATCH v23 13/13] x86, vdso32: handle 32 bit vDSO larger one page Stefani Seibold
@ 2014-03-18 21:30   ` tip-bot for Stefani Seibold
  0 siblings, 0 replies; 30+ messages in thread
From: tip-bot for Stefani Seibold @ 2014-03-18 21:30 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, stefani, tglx, hpa

Commit-ID:  4e40112c4ff6a577dd06d92b2a54cdf06265bf74
Gitweb:     http://git.kernel.org/tip/4e40112c4ff6a577dd06d92b2a54cdf06265bf74
Author:     Stefani Seibold <stefani@seibold.net>
AuthorDate: Mon, 17 Mar 2014 23:22:13 +0100
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 18 Mar 2014 12:52:54 -0700

x86, vdso32: handle 32 bit vDSO larger one page

This patch enables 32 bit vDSO which are larger than a page.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-14-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/vdso/vdso32-setup.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e10abdf..5b4aaef 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -16,6 +16,7 @@
 #include <linux/mm.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 
 #include <asm/cpufeature.h>
 #include <asm/msr.h>
@@ -69,7 +70,8 @@ __setup_param("vdso=", vdso32_setup, vdso_setup, 0);
 EXPORT_SYMBOL_GPL(vdso_enabled);
 #endif
 
-static struct page *vdso32_pages[1];
+static struct page **vdso32_pages;
+static unsigned int vdso32_size;
 
 #ifdef CONFIG_X86_64
 
@@ -115,11 +117,10 @@ void enable_sep_cpu(void)
 
 int __init sysenter_setup(void)
 {
-	void *vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
+	void *vdso_pages;
 	const void *vdso;
 	size_t vdso_len;
-
-	vdso32_pages[0] = virt_to_page(vdso_page);
+	unsigned int i;
 
 	if (vdso32_syscall()) {
 		vdso = &vdso32_syscall_start;
@@ -132,8 +133,15 @@ int __init sysenter_setup(void)
 		vdso_len = &vdso32_int80_end - &vdso32_int80_start;
 	}
 
-	memcpy(vdso_page, vdso, vdso_len);
-	patch_vdso32(vdso_page, vdso_len);
+	vdso32_size = (vdso_len + PAGE_SIZE - 1) / PAGE_SIZE;
+	vdso32_pages = kmalloc(sizeof(*vdso32_pages) * vdso32_size, GFP_ATOMIC);
+	vdso_pages = kmalloc(VDSO_OFFSET(vdso32_size), GFP_ATOMIC);
+
+	for(i = 0; i != vdso32_size; ++i)
+		vdso32_pages[i] = virt_to_page(vdso_pages + VDSO_OFFSET(i));
+
+	memcpy(vdso_pages, vdso, vdso_len);
+	patch_vdso32(vdso_pages, vdso_len);
 
 	return 0;
 }
@@ -169,7 +177,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	 */
 	ret = install_special_mapping(mm,
 			addr,
-			VDSO_OFFSET(VDSO_PAGES - VDSO_PREV_PAGES),
+			VDSO_OFFSET(vdso32_size),
 			VM_READ|VM_EXEC|
 			VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
 			vdso32_pages);

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* Re: [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
  2014-03-17 22:22 ` [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 " Stefani Seibold
  2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
@ 2014-03-27 20:44   ` John Stultz
  2014-03-27 21:12     ` Andy Lutomirski
  2014-03-27 22:35     ` H. Peter Anvin
  1 sibling, 2 replies; 30+ messages in thread
From: John Stultz @ 2014-03-27 20:44 UTC (permalink / raw)
  To: Stefani Seibold, gregkh, linux-kernel, x86, tglx, mingo, hpa, ak,
	aarcange, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief

On 03/17/2014 03:22 PM, Stefani Seibold wrote:
> This patch add the VDSO time support for the IA32 Emulation Layer.
>
> Due the nature of the kernel headers and the LP64 compiler where the
> size of a long and a pointer differs against a 32 bit compiler, there
> is some type hacking necessary for optimal performance.
>
> The vsyscall_gtod_data struture must be a rearranged to serve 32- and
> 64-bit code access at the same time:
>
> - The seqcount_t was replaced by an unsigned, this makes the
>   vsyscall_gtod_data intedepend of kernel configuration and internal functions.
> - All kernel internal structures are replaced by fix size elements
>   which works for 32- and 64-bit access
> - The inner struct clock was removed to pack the whole struct.
>
> The "unsigned seq" would be handled by functions derivated from seqcount_t.

Sorry for being a bit late on the review here. I've been focused on some
other things and figured I'd leave things to the x86 maintainers, since
it didn't touch any core timekeeping code. But Andy pinged me after
LSF-MM and so I'm trying to take a closer look.

I know this has gone through tons of iterations, and I really am glad
for Stefani's persistence. Also I do realize its already in the tip
tree, so my thoughts here are probably too late to be worth much.

> Signed-off-by: Stefani Seibold <stefani@seibold.net>
> ---
>  arch/x86/include/asm/vgtod.h          | 71 +++++++++++++++++++++------
>  arch/x86/include/asm/vvar.h           |  5 ++
>  arch/x86/kernel/vsyscall_gtod.c       | 34 ++++++++-----
>  arch/x86/vdso/vclock_gettime.c        | 91 +++++++++++++++++++----------------
>  arch/x86/vdso/vdso32/vclock_gettime.c | 21 ++++++++
>  5 files changed, 155 insertions(+), 67 deletions(-)

My initial issue with this patch is it is doing quite a few things that
could have been split up a bit. There's a number of separate cleanups:
seqlock change, the read_hpet_counter() cleanup, the vsyscall_gtod_data
structure rework, and finally the gtod_long_t and  VDSO32_64 changes.

Its probably too late now, but in the future it might be good to try to
split these sorts of things up in smaller chunks.

Overall, I don't see any obvious correctness issues with the code, so it
looks ok to me, but I really worry the amount of open-coded logic and
the quirkiness of trying to make the vsyscall_gtod_data structure usable
for both architectures at the same time really makes this code quite
fragile. Looking over this there were lots of "oh, that's broken..
wait.. no.. actually that will work" moments. So I'm worried about the
maintenance burden in the future from it. 

Having separate structures that are filled by update_vsyscall might be
nice to avoid needing the open-coded bits, but that would require
basically making a copy of all the data in the structure each update, so
that might not be worth the cost.

So as long as the x86 folks are ok with being on the hook for it, I'll
not get in the way (most other arches have quirky/ugly implementations
for their vdso/vsyscall/fsyscall/etc, so why not join the club :).

I did run this through my timekeeping test suite and on 64bit nothing
broke w/ either 32 or 64bit binaries, but I also don't have the glibc
changes to enable the 32bit vdso, so all that says is its not showing
any regressions for my existing setup.

thanks
-john

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
  2014-03-27 20:44   ` [PATCH v23 10/13] " John Stultz
@ 2014-03-27 21:12     ` Andy Lutomirski
  2014-03-27 22:35     ` H. Peter Anvin
  1 sibling, 0 replies; 30+ messages in thread
From: Andy Lutomirski @ 2014-03-27 21:12 UTC (permalink / raw)
  To: John Stultz
  Cc: Stefani Seibold, Greg KH, linux-kernel@vger.kernel.org, X86 ML,
	Thomas Gleixner, Ingo Molnar, H. Peter Anvin, Andi Kleen,
	Andrea Arcangeli, Pavel Emelyanov, Cyrill Gorcunov,
	Andy Shevchenko, Martin Runge, Andreas Brief

On Thu, Mar 27, 2014 at 1:44 PM, John Stultz <john.stultz@linaro.org> wrote:
> On 03/17/2014 03:22 PM, Stefani Seibold wrote:
>> This patch add the VDSO time support for the IA32 Emulation Layer.
>>
>> Due the nature of the kernel headers and the LP64 compiler where the
>> size of a long and a pointer differs against a 32 bit compiler, there
>> is some type hacking necessary for optimal performance.
>>
>> The vsyscall_gtod_data struture must be a rearranged to serve 32- and
>> 64-bit code access at the same time:
>>
>> - The seqcount_t was replaced by an unsigned, this makes the
>>   vsyscall_gtod_data intedepend of kernel configuration and internal functions.
>> - All kernel internal structures are replaced by fix size elements
>>   which works for 32- and 64-bit access
>> - The inner struct clock was removed to pack the whole struct.
>>
>> The "unsigned seq" would be handled by functions derivated from seqcount_t.
>
> Sorry for being a bit late on the review here. I've been focused on some
> other things and figured I'd leave things to the x86 maintainers, since
> it didn't touch any core timekeeping code. But Andy pinged me after
> LSF-MM and so I'm trying to take a closer look.
>
> I know this has gone through tons of iterations, and I really am glad
> for Stefani's persistence. Also I do realize its already in the tip
> tree, so my thoughts here are probably too late to be worth much.
>
>
>> Signed-off-by: Stefani Seibold <stefani@seibold.net>
>> ---
>>  arch/x86/include/asm/vgtod.h          | 71 +++++++++++++++++++++------
>>  arch/x86/include/asm/vvar.h           |  5 ++
>>  arch/x86/kernel/vsyscall_gtod.c       | 34 ++++++++-----
>>  arch/x86/vdso/vclock_gettime.c        | 91 +++++++++++++++++++----------------
>>  arch/x86/vdso/vdso32/vclock_gettime.c | 21 ++++++++
>>  5 files changed, 155 insertions(+), 67 deletions(-)
>
> My initial issue with this patch is it is doing quite a few things that
> could have been split up a bit. There's a number of separate cleanups:
> seqlock change, the read_hpet_counter() cleanup, the vsyscall_gtod_data
> structure rework, and finally the gtod_long_t and  VDSO32_64 changes.
>
> Its probably too late now, but in the future it might be good to try to
> split these sorts of things up in smaller chunks.
>
> Overall, I don't see any obvious correctness issues with the code, so it
> looks ok to me, but I really worry the amount of open-coded logic and
> the quirkiness of trying to make the vsyscall_gtod_data structure usable
> for both architectures at the same time really makes this code quite
> fragile. Looking over this there were lots of "oh, that's broken..
> wait.. no.. actually that will work" moments. So I'm worried about the
> maintenance burden in the future from it.
>
> Having separate structures that are filled by update_vsyscall might be
> nice to avoid needing the open-coded bits, but that would require
> basically making a copy of all the data in the structure each update, so
> that might not be worth the cost.

This may actually enable a future cleanup: currently, the x32 vdso is
built with gcc in 64-bit mode, and objcopy turns the result into a
32-bit file.  This structure munging, along with a cleanup I'm working
on, will eliminate the need to do that.


>
> So as long as the x86 folks are ok with being on the hook for it, I'll
> not get in the way (most other arches have quirky/ugly implementations
> for their vdso/vsyscall/fsyscall/etc, so why not join the club :).
>
> I did run this through my timekeeping test suite and on 64bit nothing
> broke w/ either 32 or 64bit binaries, but I also don't have the glibc
> changes to enable the 32bit vdso, so all that says is its not showing
> any regressions for my existing setup.

Thanks for looking!

--Andy

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
  2014-03-27 20:44   ` [PATCH v23 10/13] " John Stultz
  2014-03-27 21:12     ` Andy Lutomirski
@ 2014-03-27 22:35     ` H. Peter Anvin
  1 sibling, 0 replies; 30+ messages in thread
From: H. Peter Anvin @ 2014-03-27 22:35 UTC (permalink / raw)
  To: John Stultz, Stefani Seibold, gregkh, linux-kernel, x86, tglx,
	mingo, ak, aarcange, luto, xemul, gorcunov, andriy.shevchenko
  Cc: Martin.Runge, Andreas.Brief

I am hoping that we well get further cleanups, but art this point I'm not sure it is worth blocking it for 3.15 over that 

On March 27, 2014 1:44:00 PM PDT, John Stultz <john.stultz@linaro.org> wrote:
>On 03/17/2014 03:22 PM, Stefani Seibold wrote:
>> This patch add the VDSO time support for the IA32 Emulation Layer.
>>
>> Due the nature of the kernel headers and the LP64 compiler where the
>> size of a long and a pointer differs against a 32 bit compiler, there
>> is some type hacking necessary for optimal performance.
>>
>> The vsyscall_gtod_data struture must be a rearranged to serve 32- and
>> 64-bit code access at the same time:
>>
>> - The seqcount_t was replaced by an unsigned, this makes the
>>   vsyscall_gtod_data intedepend of kernel configuration and internal
>functions.
>> - All kernel internal structures are replaced by fix size elements
>>   which works for 32- and 64-bit access
>> - The inner struct clock was removed to pack the whole struct.
>>
>> The "unsigned seq" would be handled by functions derivated from
>seqcount_t.
>
>Sorry for being a bit late on the review here. I've been focused on
>some
>other things and figured I'd leave things to the x86 maintainers, since
>it didn't touch any core timekeeping code. But Andy pinged me after
>LSF-MM and so I'm trying to take a closer look.
>
>I know this has gone through tons of iterations, and I really am glad
>for Stefani's persistence. Also I do realize its already in the tip
>tree, so my thoughts here are probably too late to be worth much.
>
>
>> Signed-off-by: Stefani Seibold <stefani@seibold.net>
>> ---
>>  arch/x86/include/asm/vgtod.h          | 71
>+++++++++++++++++++++------
>>  arch/x86/include/asm/vvar.h           |  5 ++
>>  arch/x86/kernel/vsyscall_gtod.c       | 34 ++++++++-----
>>  arch/x86/vdso/vclock_gettime.c        | 91
>+++++++++++++++++++----------------
>>  arch/x86/vdso/vdso32/vclock_gettime.c | 21 ++++++++
>>  5 files changed, 155 insertions(+), 67 deletions(-)
>
>My initial issue with this patch is it is doing quite a few things that
>could have been split up a bit. There's a number of separate cleanups:
>seqlock change, the read_hpet_counter() cleanup, the vsyscall_gtod_data
>structure rework, and finally the gtod_long_t and  VDSO32_64 changes.
>
>Its probably too late now, but in the future it might be good to try to
>split these sorts of things up in smaller chunks.
>
>Overall, I don't see any obvious correctness issues with the code, so
>it
>looks ok to me, but I really worry the amount of open-coded logic and
>the quirkiness of trying to make the vsyscall_gtod_data structure
>usable
>for both architectures at the same time really makes this code quite
>fragile. Looking over this there were lots of "oh, that's broken..
>wait.. no.. actually that will work" moments. So I'm worried about the
>maintenance burden in the future from it. 
>
>Having separate structures that are filled by update_vsyscall might be
>nice to avoid needing the open-coded bits, but that would require
>basically making a copy of all the data in the structure each update,
>so
>that might not be worth the cost.
>
>So as long as the x86 folks are ok with being on the hook for it, I'll
>not get in the way (most other arches have quirky/ugly implementations
>for their vdso/vsyscall/fsyscall/etc, so why not join the club :).
>
>I did run this through my timekeeping test suite and on 64bit nothing
>broke w/ either 32 or 64bit binaries, but I also don't have the glibc
>changes to enable the 32bit vdso, so all that says is its not showing
>any regressions for my existing setup.
>
>thanks
>-john

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

^ permalink raw reply	[flat|nested] 30+ messages in thread

end of thread, other threads:[~2014-03-27 22:37 UTC | newest]

Thread overview: 30+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-03-17 22:22 [PATCH v23 00/13] x86: Add x86 32 bit VDSO time function support Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 01/13] x86, vdso: Make vsyscall_gtod_data handling x86 generic Stefani Seibold
2014-03-18 21:27   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 02/13] mm: Add new func _install_special_mapping() to mmap.c Stefani Seibold
2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 03/13] x86, vdso: Revamp vclock_gettime.c Stefani Seibold
2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 04/13] x86, vdso: __vdso_clock_gettime() cleanup Stefani Seibold
2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 05/13] x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro Stefani Seibold
2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 06/13] x86, vdso: Cleanup __vdso_gettimeofday() Stefani Seibold
2014-03-18 21:28   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 07/13] x86, vdso: Introduce VVAR marco for vdso32 Stefani Seibold
2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 08/13] x86, vdso: Patch alternatives in the 32-bit VDSO Stefani Seibold
2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2014-03-17 22:22 ` [PATCH v23 09/13] x86, vdso: Add 32 bit VDSO time support for 32 bit kernel Stefani Seibold
2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-17 22:22 ` [PATCH v23 10/13] x86, vdso: Add 32 bit VDSO time support for 64 " Stefani Seibold
2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Stefani Seibold
2014-03-27 20:44   ` [PATCH v23 10/13] " John Stultz
2014-03-27 21:12     ` Andy Lutomirski
2014-03-27 22:35     ` H. Peter Anvin
2014-03-17 22:22 ` [PATCH v23 11/13] x86, vdso: Zero-pad the VVAR page Stefani Seibold
2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for Andy Lutomirski
2014-03-17 22:22 ` [PATCH v23 12/13] x86, vdso32: Disable stack protector, adjust optimizations Stefani Seibold
2014-03-18 21:29   ` [tip:x86/vdso] " tip-bot for H. Peter Anvin
2014-03-17 22:22 ` [PATCH v23 13/13] x86, vdso32: handle 32 bit vDSO larger one page Stefani Seibold
2014-03-18 21:30   ` [tip:x86/vdso] " tip-bot for Stefani Seibold

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