[PATCH v2 00/10] x86 and others: vsyscall and vdso cleanups

[PATCH v2 00/10] x86 and others: vsyscall and vdso cleanups

[Andy Lutomirski]

This is v2.  I'm resending it because the fallout from the 3.16 changes
seems to have settled down, and because arm is about to run in to the
same problem that I ran in to, which is fixed in the big cross-arch
patch.

Patch 1 fixes a minor bug; it might make sense to backport it.

Patch 3 removes the vsyscall mapping when vsyscall=none.

Patch 4 and 5 remove some unnecessary vvars.  gtod is the only one left now.

Patch 9 is a big cross-arch cleanup.  The old code was supposedly
generic, but it was only useful for ia64, and it was actively harmful
for lots of other architectures.

Patch 10 makes vsyscall emulation optional.  It's hidden under
CONFIG_EXPERT.

If this should be split or reordered, please let me know.

NB: I wouldn't be surprised if Nathan Lynch ends up wanting patch 9 for
ARM's upcoming vdso, so it would be nice to get at least that patch into
an upstream-pointing git tree somewhere.  I'm not sure what the
appropriate tree is.

Changes from v1:
 - Rebased to 3.16-rc3.
 - The last patch is new.

Andy Lutomirski (10):
  x86_64,vsyscall: Fix warn_bad_vsyscall log output
  x86_64,vsyscall: Move all of the gate_area code to vsyscall_64.c
  x86_64,vsyscall: Turn vsyscalls all the way off when vsyscall=none
  x86_64,vdso: Remove jiffies from the vvar page
  x86,vdso: Replace vgetcpu_mode with static_cpu_has
  x86_64: Move getcpu code from vsyscall_64.c to vdso/vma.c
  x86_64,vsyscall: Rewrite comment and clean up headers in vsyscall code
  x86_64,vdso: Clean up vgetcpu init and merge the vdso initcalls
  arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area
  x86_64,vsyscall: Make vsyscall emulation configurable

 arch/arm64/include/asm/page.h      |   3 -
 arch/arm64/kernel/vdso.c           |  19 -----
 arch/ia64/include/asm/page.h       |   2 +
 arch/ia64/mm/init.c                |  26 +++++++
 arch/powerpc/include/asm/page.h    |   3 -
 arch/powerpc/kernel/vdso.c         |  16 ----
 arch/s390/include/asm/page.h       |   2 -
 arch/s390/kernel/vdso.c            |  15 ----
 arch/sh/include/asm/page.h         |   5 --
 arch/sh/kernel/vsyscall/vsyscall.c |  15 ----
 arch/tile/include/asm/page.h       |   6 --
 arch/tile/kernel/vdso.c            |  15 ----
 arch/um/include/asm/page.h         |   5 ++
 arch/x86/Kconfig                   |  18 +++++
 arch/x86/include/asm/fixmap.h      |   2 +
 arch/x86/include/asm/page.h        |   1 -
 arch/x86/include/asm/page_64.h     |   4 +
 arch/x86/include/asm/vgtod.h       |  21 +++++
 arch/x86/include/asm/vsyscall.h    |  33 ++------
 arch/x86/include/asm/vvar.h        |   2 -
 arch/x86/kernel/Makefile           |   3 +-
 arch/x86/kernel/cpu/common.c       |  10 ---
 arch/x86/kernel/setup.c            |   2 -
 arch/x86/kernel/time.c             |   2 +-
 arch/x86/kernel/vsyscall_64.c      | 155 ++++++++++++++++---------------------
 arch/x86/mm/init_64.c              |  49 ------------
 arch/x86/um/asm/elf.h              |   1 -
 arch/x86/um/mem_64.c               |  15 ----
 arch/x86/vdso/vclock_gettime.c     |   3 +
 arch/x86/vdso/vdso32-setup.c       |  19 +----
 arch/x86/vdso/vgetcpu.c            |   5 +-
 arch/x86/vdso/vma.c                |  81 ++++++++++++++-----
 arch/x86/xen/mmu.c                 |   6 +-
 include/linux/mm.h                 |  17 ++--
 mm/memory.c                        |  38 ---------
 mm/nommu.c                         |   5 --
 36 files changed, 239 insertions(+), 385 deletions(-)

-- 
1.9.3

[PATCH v2 01/10] x86_64,vsyscall: Fix warn_bad_vsyscall log output

[Andy Lutomirski]

This commit in Linux 3.6:

    commit c767a54ba0657e52e6edaa97cbe0b0a8bf1c1655
    Author: Joe Perches <joe@perches.com>
    Date:   Mon May 21 19:50:07 2012 -0700

        x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>

caused warn_bad_vsyscall to output garbage in the middle of the
line.  Revert the bad part of it.

The printk in question isn't actually bare; the level is "%s".

The bug this fixes is purely cosmetic; backports are optional.

Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/kernel/vsyscall_64.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index ea5b570..e1e1e80 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -81,10 +81,10 @@ static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
 	if (!show_unhandled_signals)
 		return;
 
-	pr_notice_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
-			      level, current->comm, task_pid_nr(current),
-			      message, regs->ip, regs->cs,
-			      regs->sp, regs->ax, regs->si, regs->di);
+	printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
+			   level, current->comm, task_pid_nr(current),
+			   message, regs->ip, regs->cs,
+			   regs->sp, regs->ax, regs->si, regs->di);
 }
 
 static int addr_to_vsyscall_nr(unsigned long addr)
-- 
1.9.3

[PATCH v2 02/10] x86_64,vsyscall: Move all of the gate_area code to vsyscall_64.c

[Andy Lutomirski]

This code exists for the sole purpose of making the vsyscall page
look sort of like real userspace memory.  Move it so that it lives
with the rest of the vsyscall code.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/kernel/vsyscall_64.c | 49 +++++++++++++++++++++++++++++++++++++++++++
 arch/x86/mm/init_64.c         | 49 -------------------------------------------
 2 files changed, 49 insertions(+), 49 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index e1e1e80..420c468 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -284,6 +284,55 @@ sigsegv:
 }
 
 /*
+ * A pseudo VMA to allow ptrace access for the vsyscall page.  This only
+ * covers the 64bit vsyscall page now. 32bit has a real VMA now and does
+ * not need special handling anymore:
+ */
+static const char *gate_vma_name(struct vm_area_struct *vma)
+{
+	return "[vsyscall]";
+}
+static struct vm_operations_struct gate_vma_ops = {
+	.name = gate_vma_name,
+};
+static struct vm_area_struct gate_vma = {
+	.vm_start	= VSYSCALL_ADDR,
+	.vm_end		= VSYSCALL_ADDR + PAGE_SIZE,
+	.vm_page_prot	= PAGE_READONLY_EXEC,
+	.vm_flags	= VM_READ | VM_EXEC,
+	.vm_ops		= &gate_vma_ops,
+};
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+#ifdef CONFIG_IA32_EMULATION
+	if (!mm || mm->context.ia32_compat)
+		return NULL;
+#endif
+	return &gate_vma;
+}
+
+int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	struct vm_area_struct *vma = get_gate_vma(mm);
+
+	if (!vma)
+		return 0;
+
+	return (addr >= vma->vm_start) && (addr < vma->vm_end);
+}
+
+/*
+ * Use this when you have no reliable mm, typically from interrupt
+ * context. It is less reliable than using a task's mm and may give
+ * false positives.
+ */
+int in_gate_area_no_mm(unsigned long addr)
+{
+	return (addr & PAGE_MASK) == VSYSCALL_ADDR;
+}
+
+/*
  * Assume __initcall executes before all user space. Hopefully kmod
  * doesn't violate that. We'll find out if it does.
  */
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index df1a992..417ea05 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1180,55 +1180,6 @@ int kern_addr_valid(unsigned long addr)
 	return pfn_valid(pte_pfn(*pte));
 }
 
-/*
- * A pseudo VMA to allow ptrace access for the vsyscall page.  This only
- * covers the 64bit vsyscall page now. 32bit has a real VMA now and does
- * not need special handling anymore:
- */
-static const char *gate_vma_name(struct vm_area_struct *vma)
-{
-	return "[vsyscall]";
-}
-static struct vm_operations_struct gate_vma_ops = {
-	.name = gate_vma_name,
-};
-static struct vm_area_struct gate_vma = {
-	.vm_start	= VSYSCALL_ADDR,
-	.vm_end		= VSYSCALL_ADDR + PAGE_SIZE,
-	.vm_page_prot	= PAGE_READONLY_EXEC,
-	.vm_flags	= VM_READ | VM_EXEC,
-	.vm_ops		= &gate_vma_ops,
-};
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef CONFIG_IA32_EMULATION
-	if (!mm || mm->context.ia32_compat)
-		return NULL;
-#endif
-	return &gate_vma;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	struct vm_area_struct *vma = get_gate_vma(mm);
-
-	if (!vma)
-		return 0;
-
-	return (addr >= vma->vm_start) && (addr < vma->vm_end);
-}
-
-/*
- * Use this when you have no reliable mm, typically from interrupt
- * context. It is less reliable than using a task's mm and may give
- * false positives.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return (addr & PAGE_MASK) == VSYSCALL_ADDR;
-}
-
 static unsigned long probe_memory_block_size(void)
 {
 	/* start from 2g */
-- 
1.9.3

[PATCH v2 03/10] x86_64,vsyscall: Turn vsyscalls all the way off when vsyscall=none

[Andy Lutomirski]

I see no point in having an unusable read-only page sitting at
0xffffffffff600000 when vsyscall=none.  Instead, skip mapping it and
remove it from /proc/PID/maps.

I kept the ratelimited warning when programs try to use a vsyscall
in this mode, since it may help admins avoid confusion.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/kernel/vsyscall_64.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 420c468..6463f9e 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -309,6 +309,8 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 	if (!mm || mm->context.ia32_compat)
 		return NULL;
 #endif
+	if (vsyscall_mode == NONE)
+		return NULL;
 	return &gate_vma;
 }
 
@@ -329,7 +331,7 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr)
  */
 int in_gate_area_no_mm(unsigned long addr)
 {
-	return (addr & PAGE_MASK) == VSYSCALL_ADDR;
+	return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR;
 }
 
 /*
@@ -380,10 +382,12 @@ void __init map_vsyscall(void)
 	extern char __vsyscall_page;
 	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
 
-	__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
-		     vsyscall_mode == NATIVE
-		     ? PAGE_KERNEL_VSYSCALL
-		     : PAGE_KERNEL_VVAR);
+	if (vsyscall_mode != NONE)
+		__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
+			     vsyscall_mode == NATIVE
+			     ? PAGE_KERNEL_VSYSCALL
+			     : PAGE_KERNEL_VVAR);
+
 	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
 		     (unsigned long)VSYSCALL_ADDR);
 }
-- 
1.9.3

[PATCH v2 04/10] x86_64,vdso: Remove jiffies from the vvar page

[Andy Lutomirski]

I think that the jiffies vvar was once used for the vgetcpu cache.
That code is long gone, so let's just make jiffies be a normal
variable.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/include/asm/vvar.h | 1 -
 arch/x86/kernel/time.c      | 2 +-
 arch/x86/vdso/vgetcpu.c     | 1 -
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 5d2b9ad..5f6d407 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -44,7 +44,6 @@ extern char __vvar_page;
 
 /* DECLARE_VVAR(offset, type, name) */
 
-DECLARE_VVAR(0, volatile unsigned long, jiffies)
 DECLARE_VVAR(16, int, vgetcpu_mode)
 DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data)
 
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index bf7ef5c..822773b 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -23,7 +23,7 @@
 #include <asm/time.h>
 
 #ifdef CONFIG_X86_64
-__visible DEFINE_VVAR(volatile unsigned long, jiffies) = INITIAL_JIFFIES;
+__visible volatile unsigned long jiffies __cacheline_aligned = INITIAL_JIFFIES;
 #endif
 
 unsigned long profile_pc(struct pt_regs *regs)
diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c
index 2f94b03..add1d98 100644
--- a/arch/x86/vdso/vgetcpu.c
+++ b/arch/x86/vdso/vgetcpu.c
@@ -7,7 +7,6 @@
 
 #include <linux/kernel.h>
 #include <linux/getcpu.h>
-#include <linux/jiffies.h>
 #include <linux/time.h>
 #include <asm/vsyscall.h>
 #include <asm/vgtod.h>
-- 
1.9.3

[PATCH v2 05/10] x86,vdso: Replace vgetcpu_mode with static_cpu_has

[Andy Lutomirski]

The vdso has supported alternatives for a while; use them instead of
a vvar to select the vgetcpu mode.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/include/asm/vgtod.h    | 21 +++++++++++++++++++++
 arch/x86/include/asm/vsyscall.h | 29 -----------------------------
 arch/x86/include/asm/vvar.h     |  1 -
 arch/x86/kernel/cpu/common.c    | 10 ----------
 arch/x86/kernel/vsyscall_64.c   |  2 --
 arch/x86/vdso/vclock_gettime.c  |  3 +++
 arch/x86/vdso/vgetcpu.c         |  4 +++-
 arch/x86/vdso/vma.c             |  1 +
 8 files changed, 28 insertions(+), 43 deletions(-)

diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index 3c3366c..44e0037 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -70,4 +70,25 @@ static inline void gtod_write_end(struct vsyscall_gtod_data *s)
 	++s->seq;
 }
 
+#ifdef CONFIG_X86_64
+
+#define VGETCPU_CPU_MASK 0xfff
+
+static inline unsigned int __getcpu(void)
+{
+	unsigned int p;
+
+	if (static_cpu_has(X86_FEATURE_RDTSCP)) {
+		/* Load per CPU data from RDTSCP */
+		native_read_tscp(&p);
+	} else {
+		/* Load per CPU data from GDT */
+		asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
+	}
+
+	return p;
+}
+
+#endif /* CONFIG_X86_64 */
+
 #endif /* _ASM_X86_VGTOD_H */
diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h
index 2a46ca7..34f7d88 100644
--- a/arch/x86/include/asm/vsyscall.h
+++ b/arch/x86/include/asm/vsyscall.h
@@ -4,15 +4,6 @@
 #include <linux/seqlock.h>
 #include <uapi/asm/vsyscall.h>
 
-#define VGETCPU_RDTSCP	1
-#define VGETCPU_LSL	2
-
-/* kernel space (writeable) */
-extern int vgetcpu_mode;
-extern struct timezone sys_tz;
-
-#include <asm/vvar.h>
-
 extern void map_vsyscall(void);
 
 /*
@@ -21,24 +12,4 @@ extern void map_vsyscall(void);
  */
 extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address);
 
-#ifdef CONFIG_X86_64
-
-#define VGETCPU_CPU_MASK 0xfff
-
-static inline unsigned int __getcpu(void)
-{
-	unsigned int p;
-
-	if (VVAR(vgetcpu_mode) == VGETCPU_RDTSCP) {
-		/* Load per CPU data from RDTSCP */
-		native_read_tscp(&p);
-	} else {
-		/* Load per CPU data from GDT */
-		asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
-	}
-
-	return p;
-}
-#endif /* CONFIG_X86_64 */
-
 #endif /* _ASM_X86_VSYSCALL_H */
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 5f6d407..3f32dfc 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -44,7 +44,6 @@ extern char __vvar_page;
 
 /* DECLARE_VVAR(offset, type, name) */
 
-DECLARE_VVAR(16, int, vgetcpu_mode)
 DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data)
 
 #undef DECLARE_VVAR
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ef1b93f..becea69 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -948,14 +948,6 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 }
 
 #ifdef CONFIG_X86_64
-static void vgetcpu_set_mode(void)
-{
-	if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
-		vgetcpu_mode = VGETCPU_RDTSCP;
-	else
-		vgetcpu_mode = VGETCPU_LSL;
-}
-
 /* May not be __init: called during resume */
 static void syscall32_cpu_init(void)
 {
@@ -996,8 +988,6 @@ void __init identify_boot_cpu(void)
 #ifdef CONFIG_X86_32
 	sysenter_setup();
 	enable_sep_cpu();
-#else
-	vgetcpu_set_mode();
 #endif
 	cpu_detect_tlb(&boot_cpu_data);
 }
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 6463f9e..dd1b322 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -52,8 +52,6 @@
 #define CREATE_TRACE_POINTS
 #include "vsyscall_trace.h"
 
-DEFINE_VVAR(int, vgetcpu_mode);
-
 static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
 
 static int __init vsyscall_setup(char *str)
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 9793322..d14bb8f 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -11,6 +11,9 @@
  * Check with readelf after changing.
  */
 
+/* Disable static_cpu_has debugging; it doesn't work in the vDSO */
+#undef CONFIG_X86_DEBUG_STATIC_CPU_HAS
+
 #include <uapi/linux/time.h>
 #include <asm/vgtod.h>
 #include <asm/hpet.h>
diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c
index add1d98..fd8470c 100644
--- a/arch/x86/vdso/vgetcpu.c
+++ b/arch/x86/vdso/vgetcpu.c
@@ -5,10 +5,12 @@
  * Fast user context implementation of getcpu()
  */
 
+/* Disable static_cpu_has debugging; it doesn't work in the vDSO */
+#undef CONFIG_X86_DEBUG_STATIC_CPU_HAS
+
 #include <linux/kernel.h>
 #include <linux/getcpu.h>
 #include <linux/time.h>
-#include <asm/vsyscall.h>
 #include <asm/vgtod.h>
 
 notrace long
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index e1513c4..67a8b6c 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>
 #include <asm/hpet.h>
+#include <asm/vvar.h>
 
 #if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso64_enabled = 1;
-- 
1.9.3

[PATCH v2 06/10] x86_64: Move getcpu code from vsyscall_64.c to vdso/vma.c

[Andy Lutomirski]

This is pure cut-and-paste.  At this point, vsyscall_64.c contains
only code needed for vsyscall emulation, but some of the comments
and function names are still confused.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/kernel/vsyscall_64.c | 57 ----------------------------------------
 arch/x86/vdso/vma.c           | 61 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 57 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index dd1b322..5029be3 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -332,49 +332,6 @@ int in_gate_area_no_mm(unsigned long addr)
 	return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR;
 }
 
-/*
- * Assume __initcall executes before all user space. Hopefully kmod
- * doesn't violate that. We'll find out if it does.
- */
-static void vsyscall_set_cpu(int cpu)
-{
-	unsigned long d;
-	unsigned long node = 0;
-#ifdef CONFIG_NUMA
-	node = cpu_to_node(cpu);
-#endif
-	if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP))
-		write_rdtscp_aux((node << 12) | cpu);
-
-	/*
-	 * Store cpu number in limit so that it can be loaded quickly
-	 * in user space in vgetcpu. (12 bits for the CPU and 8 bits for the node)
-	 */
-	d = 0x0f40000000000ULL;
-	d |= cpu;
-	d |= (node & 0xf) << 12;
-	d |= (node >> 4) << 48;
-
-	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
-}
-
-static void cpu_vsyscall_init(void *arg)
-{
-	/* preemption should be already off */
-	vsyscall_set_cpu(raw_smp_processor_id());
-}
-
-static int
-cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
-{
-	long cpu = (long)arg;
-
-	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
-		smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
-
-	return NOTIFY_DONE;
-}
-
 void __init map_vsyscall(void)
 {
 	extern char __vsyscall_page;
@@ -389,17 +346,3 @@ void __init map_vsyscall(void)
 	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
 		     (unsigned long)VSYSCALL_ADDR);
 }
-
-static int __init vsyscall_init(void)
-{
-	cpu_notifier_register_begin();
-
-	on_each_cpu(cpu_vsyscall_init, NULL, 1);
-	/* notifier priority > KVM */
-	__hotcpu_notifier(cpu_vsyscall_notifier, 30);
-
-	cpu_notifier_register_done();
-
-	return 0;
-}
-__initcall(vsyscall_init);
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 67a8b6c..8973b4e 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -10,6 +10,7 @@
 #include <linux/init.h>
 #include <linux/random.h>
 #include <linux/elf.h>
+#include <linux/cpu.h>
 #include <asm/vsyscall.h>
 #include <asm/vgtod.h>
 #include <asm/proto.h>
@@ -17,6 +18,7 @@
 #include <asm/page.h>
 #include <asm/hpet.h>
 #include <asm/vvar.h>
+#include <asm/desc.h>
 
 #if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso64_enabled = 1;
@@ -233,3 +235,62 @@ static __init int vdso_setup(char *s)
 }
 __setup("vdso=", vdso_setup);
 #endif
+
+#ifdef CONFIG_X86_64
+/*
+ * Assume __initcall executes before all user space. Hopefully kmod
+ * doesn't violate that. We'll find out if it does.
+ */
+static void vsyscall_set_cpu(int cpu)
+{
+	unsigned long d;
+	unsigned long node = 0;
+#ifdef CONFIG_NUMA
+	node = cpu_to_node(cpu);
+#endif
+	if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP))
+		write_rdtscp_aux((node << 12) | cpu);
+
+	/*
+	 * Store cpu number in limit so that it can be loaded quickly
+	 * in user space in vgetcpu. (12 bits for the CPU and 8 bits for the node)
+	 */
+	d = 0x0f40000000000ULL;
+	d |= cpu;
+	d |= (node & 0xf) << 12;
+	d |= (node >> 4) << 48;
+
+	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
+}
+
+static void cpu_vsyscall_init(void *arg)
+{
+	/* preemption should be already off */
+	vsyscall_set_cpu(raw_smp_processor_id());
+}
+
+static int
+cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
+{
+	long cpu = (long)arg;
+
+	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
+		smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
+
+	return NOTIFY_DONE;
+}
+
+static int __init vsyscall_init(void)
+{
+	cpu_notifier_register_begin();
+
+	on_each_cpu(cpu_vsyscall_init, NULL, 1);
+	/* notifier priority > KVM */
+	__hotcpu_notifier(cpu_vsyscall_notifier, 30);
+
+	cpu_notifier_register_done();
+
+	return 0;
+}
+__initcall(vsyscall_init);
+#endif
-- 
1.9.3

[PATCH v2 07/10] x86_64,vsyscall: Rewrite comment and clean up headers in vsyscall code

[Andy Lutomirski]

vsyscall_64.c is just vsyscall emulation.  Tidy it up accordingly.

If my comment editing offends anyone, let me know and I can fix it.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/kernel/vsyscall_64.c | 51 +++++++++++++++----------------------------
 1 file changed, 18 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 5029be3..1ea34e7 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -1,52 +1,37 @@
 /*
- *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- *  Copyright 2003 Andi Kleen, SuSE Labs.
+ * Mostly copyright (c) 2012-2014 Andy Lutomirski <luto@amacapital.net>
  *
- *  [ NOTE: this mechanism is now deprecated in favor of the vDSO. ]
+ * This file implements vsyscall emulation.  vsyscalls are a legacy ABI:
+ * userspace can request certain kernel services by calling fixed
+ * addresses.  This concept is problematic:
  *
- *  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.
+ * - It interferes with ASLR.
+ * - It's awkward to write code that lives in kernel addresses but is
+ *   callable by userspace at fixed addresses.
+ * - The whole concept is impossible for 32-bit compat userspace.
+ * - UML cannot easily virtualize a vsyscall.
  *
- *  vsyscall 1 is located at -10Mbyte, vsyscall 2 is located
- *  at virtual address -10Mbyte+1024bytes etc... There are at max 4
- *  vsyscalls. One vsyscall can reserve more than 1 slot to avoid
- *  jumping out of line if necessary. We cannot add more with this
- *  mechanism because older kernels won't return -ENOSYS.
+ * As of mid-2014, I believe that there is no new userspace code that
+ * will use a vsyscall if the vDSO is present.  I hope that there will
+ * soon be no new userspace code that will ever use a vsyscall.
  *
- *  Note: the concept clashes with user mode linux.  UML users should
- *  use the vDSO.
+ * The code in this file emulates vsyscalls when notified of a page
+ * fault to a vsyscall address.
+ *
+ * The original version of this code is:
+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ * Copyright 2003 Andi Kleen, SuSE Labs.
  */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/time.h>
-#include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/timer.h>
-#include <linux/seqlock.h>
-#include <linux/jiffies.h>
-#include <linux/sysctl.h>
-#include <linux/topology.h>
-#include <linux/timekeeper_internal.h>
-#include <linux/getcpu.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-#include <linux/notifier.h>
 #include <linux/syscalls.h>
 #include <linux/ratelimit.h>
 
 #include <asm/vsyscall.h>
-#include <asm/pgtable.h>
-#include <asm/compat.h>
-#include <asm/page.h>
 #include <asm/unistd.h>
 #include <asm/fixmap.h>
-#include <asm/errno.h>
-#include <asm/io.h>
-#include <asm/segment.h>
-#include <asm/desc.h>
-#include <asm/topology.h>
 #include <asm/traps.h>
 
 #define CREATE_TRACE_POINTS
-- 
1.9.3

[PATCH v2 08/10] x86_64,vdso: Clean up vgetcpu init and merge the vdso initcalls

[Andy Lutomirski]

Now vdso/vma.c has a single initcall and no references to
"vsyscall".

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/vdso/vma.c | 61 +++++++++++++++++++----------------------------------
 1 file changed, 22 insertions(+), 39 deletions(-)

diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 8973b4e..84df79b 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -1,7 +1,8 @@
 /*
- * Set up the VMAs to tell the VM about the vDSO.
  * Copyright 2007 Andi Kleen, SUSE Labs.
  * Subject to the GPL, v.2
+ *
+ * This contains most of the x86 vDSO kernel-side code.
  */
 #include <linux/mm.h>
 #include <linux/err.h>
@@ -11,7 +12,6 @@
 #include <linux/random.h>
 #include <linux/elf.h>
 #include <linux/cpu.h>
-#include <asm/vsyscall.h>
 #include <asm/vgtod.h>
 #include <asm/proto.h>
 #include <asm/vdso.h>
@@ -22,8 +22,6 @@
 
 #if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso64_enabled = 1;
-
-extern unsigned short vdso_sync_cpuid;
 #endif
 
 void __init init_vdso_image(const struct vdso_image *image)
@@ -41,20 +39,6 @@ void __init init_vdso_image(const struct vdso_image *image)
 						image->alt_len));
 }
 
-#if defined(CONFIG_X86_64)
-static int __init init_vdso(void)
-{
-	init_vdso_image(&vdso_image_64);
-
-#ifdef CONFIG_X86_X32_ABI
-	init_vdso_image(&vdso_image_x32);
-#endif
-
-	return 0;
-}
-subsys_initcall(init_vdso);
-#endif
-
 struct linux_binprm;
 
 /* Put the vdso above the (randomized) stack with another randomized offset.
@@ -237,12 +221,9 @@ __setup("vdso=", vdso_setup);
 #endif
 
 #ifdef CONFIG_X86_64
-/*
- * Assume __initcall executes before all user space. Hopefully kmod
- * doesn't violate that. We'll find out if it does.
- */
-static void vsyscall_set_cpu(int cpu)
+static void vgetcpu_cpu_init(void *arg)
 {
+	int cpu = smp_processor_id();
 	unsigned long d;
 	unsigned long node = 0;
 #ifdef CONFIG_NUMA
@@ -252,45 +233,47 @@ static void vsyscall_set_cpu(int cpu)
 		write_rdtscp_aux((node << 12) | cpu);
 
 	/*
-	 * Store cpu number in limit so that it can be loaded quickly
-	 * in user space in vgetcpu. (12 bits for the CPU and 8 bits for the node)
+	 * Store cpu number in limit so that it can be loaded quickly in
+	 * user space in vgetcpu. (12 bits for the CPU and 8 bits for
+	 * the node)
 	 */
 	d = 0x0f40000000000ULL;
 	d |= cpu;
 	d |= (node & 0xf) << 12;
 	d |= (node >> 4) << 48;
 
-	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
-}
-
-static void cpu_vsyscall_init(void *arg)
-{
-	/* preemption should be already off */
-	vsyscall_set_cpu(raw_smp_processor_id());
+	write_gdt_entry(get_cpu_gdt_table(cpu),
+			GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
 }
 
 static int
-cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
+vgetcpu_cpu_notifier(struct notifier_block *n, unsigned long action, void *arg)
 {
 	long cpu = (long)arg;
 
 	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
-		smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
+		smp_call_function_single(cpu, vgetcpu_cpu_init, NULL, 1);
 
 	return NOTIFY_DONE;
 }
 
-static int __init vsyscall_init(void)
+static int __init init_vdso(void)
 {
+	init_vdso_image(&vdso_image_64);
+
+#ifdef CONFIG_X86_X32_ABI
+	init_vdso_image(&vdso_image_x32);
+#endif
+
 	cpu_notifier_register_begin();
 
-	on_each_cpu(cpu_vsyscall_init, NULL, 1);
+	on_each_cpu(vgetcpu_cpu_init, NULL, 1);
 	/* notifier priority > KVM */
-	__hotcpu_notifier(cpu_vsyscall_notifier, 30);
+	__hotcpu_notifier(vgetcpu_cpu_notifier, 30);
 
 	cpu_notifier_register_done();
 
 	return 0;
 }
-__initcall(vsyscall_init);
-#endif
+subsys_initcall(init_vdso);
+#endif /* CONFIG_X86_64 */
-- 
1.9.3

[PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Andy Lutomirski]

The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
64-bit UML, and x86_32 have their own code just to disable it.  arm,
32-bit UML, and x86_64 have gate areas, but they have their own
implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's
now possible to inline the gate_area functions in the default case.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/arm64/include/asm/page.h      |  3 ---
 arch/arm64/kernel/vdso.c           | 19 -------------------
 arch/ia64/include/asm/page.h       |  2 ++
 arch/ia64/mm/init.c                | 26 ++++++++++++++++++++++++++
 arch/powerpc/include/asm/page.h    |  3 ---
 arch/powerpc/kernel/vdso.c         | 16 ----------------
 arch/s390/include/asm/page.h       |  2 --
 arch/s390/kernel/vdso.c            | 15 ---------------
 arch/sh/include/asm/page.h         |  5 -----
 arch/sh/kernel/vsyscall/vsyscall.c | 15 ---------------
 arch/tile/include/asm/page.h       |  6 ------
 arch/tile/kernel/vdso.c            | 15 ---------------
 arch/um/include/asm/page.h         |  5 +++++
 arch/x86/include/asm/page.h        |  1 -
 arch/x86/include/asm/page_64.h     |  2 ++
 arch/x86/um/asm/elf.h              |  1 -
 arch/x86/um/mem_64.c               | 15 ---------------
 arch/x86/vdso/vdso32-setup.c       | 19 +------------------
 include/linux/mm.h                 | 17 ++++++++++++-----
 mm/memory.c                        | 38 --------------------------------------
 mm/nommu.c                         |  5 -----
 21 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..992710f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -28,9 +28,6 @@
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_ARM64_64K_PAGES
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 50384fe..f630626 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -187,25 +187,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /*
- * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
- * Linux happy.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-/*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
 void update_vsyscall(struct timekeeper *tk)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index f1e1b2e..1f1bf14 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -231,4 +231,6 @@ get_order (unsigned long size)
 #define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)
 #define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)
 
+#define __HAVE_ARCH_GATE_AREA	1
+
 #endif /* _ASM_IA64_PAGE_H */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 25c3502..35efaa3 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -278,6 +278,32 @@ setup_gate (void)
 	ia64_patch_gate();
 }
 
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	gate_vma.vm_mm = NULL;
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
 void ia64_mmu_init(void *my_cpu_data)
 {
 	unsigned long pta, impl_va_bits;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32e4e21..26fe1ae 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT;
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ce74c33..f174351 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -840,19 +840,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 arch_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 114258e..7b2ac6e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -162,6 +162,4 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
-
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 6136490..0bbb7e0 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -316,18 +316,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 early_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 15d9703..fe20d14 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -186,11 +186,6 @@ typedef struct page *pgtable_t;
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-/* vDSO support */
-#ifdef CONFIG_VSYSCALL
-#define __HAVE_ARCH_GATE_AREA
-#endif
-
 /*
  * Some drivers need to perform DMA into kmalloc'ed buffers
  * and so we have to increase the kmalloc minalign for this.
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 5ca5797..ea2aa13 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -92,18 +92,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 6727680..a213a8d 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -39,12 +39,6 @@
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 
 /*
- * We do define AT_SYSINFO_EHDR to support vDSO,
- * but don't use the gate mechanism.
- */
-#define __HAVE_ARCH_GATE_AREA		1
-
-/*
  * If the Kconfig doesn't specify, set a maximum zone order that
  * is enough so that we can create huge pages from small pages given
  * the respective sizes of the two page types.  See <linux/mmzone.h>.
diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
index 1533af2..5bc51d7 100644
--- a/arch/tile/kernel/vdso.c
+++ b/arch/tile/kernel/vdso.c
@@ -121,21 +121,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
-
 int setup_vdso_pages(void)
 {
 	struct page **pagelist;
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 5ff53d9..71c5d13 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -119,4 +119,9 @@ extern unsigned long uml_physmem;
 #include <asm-generic/getorder.h>
 
 #endif	/* __ASSEMBLY__ */
+
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_GATE_AREA 1
+#endif
+
 #endif	/* __UM_PAGE_H */
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 775873d..802dde3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -70,7 +70,6 @@ extern bool __virt_addr_valid(unsigned long kaddr);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 
 #endif	/* __KERNEL__ */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 0f1ddee..f408caf 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,4 +39,6 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 0feee2f..25a1022 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -216,6 +216,5 @@ extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)
 
 #define SET_PERSONALITY(ex) do ; while(0)
-#define __HAVE_ARCH_GATE_AREA 1
 
 #endif
diff --git a/arch/x86/um/mem_64.c b/arch/x86/um/mem_64.c
index c6492e7..f8fecad 100644
--- a/arch/x86/um/mem_64.c
+++ b/arch/x86/um/mem_64.c
@@ -9,18 +9,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e4f7781..e904c27 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -115,23 +115,6 @@ static __init int ia32_binfmt_init(void)
 	return 0;
 }
 __initcall(ia32_binfmt_init);
-#endif
-
-#else  /* CONFIG_X86_32 */
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
+#endif /* CONFIG_SYSCTL */
 
 #endif	/* CONFIG_X86_64 */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..8981cc8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2014,13 +2014,20 @@ static inline bool kernel_page_present(struct page *page) { return true; }
 #endif /* CONFIG_HIBERNATION */
 #endif
 
+#ifdef __HAVE_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
-#ifdef	__HAVE_ARCH_GATE_AREA
-int in_gate_area_no_mm(unsigned long addr);
-int in_gate_area(struct mm_struct *mm, unsigned long addr);
+extern int in_gate_area_no_mm(unsigned long addr);
+extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
 #else
-int in_gate_area_no_mm(unsigned long addr);
-#define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
+static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
+static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
 #endif	/* __HAVE_ARCH_GATE_AREA */
 
 #ifdef CONFIG_SYSCTL
diff --git a/mm/memory.c b/mm/memory.c
index d67fd9f..099d234 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3399,44 +3399,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
 static int __follow_pte(struct mm_struct *mm, unsigned long address,
 		pte_t **ptepp, spinlock_t **ptlp)
 {
diff --git a/mm/nommu.c b/mm/nommu.c
index 4a852f6..a881d96 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1981,11 +1981,6 @@ error:
 	return -ENOMEM;
 }
 
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();
-- 
1.9.3

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[PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Andy Lutomirski]

The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
64-bit UML, and x86_32 have their own code just to disable it.  arm,
32-bit UML, and x86_64 have gate areas, but they have their own
implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's
now possible to inline the gate_area functions in the default case.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/arm64/include/asm/page.h      |  3 ---
 arch/arm64/kernel/vdso.c           | 19 -------------------
 arch/ia64/include/asm/page.h       |  2 ++
 arch/ia64/mm/init.c                | 26 ++++++++++++++++++++++++++
 arch/powerpc/include/asm/page.h    |  3 ---
 arch/powerpc/kernel/vdso.c         | 16 ----------------
 arch/s390/include/asm/page.h       |  2 --
 arch/s390/kernel/vdso.c            | 15 ---------------
 arch/sh/include/asm/page.h         |  5 -----
 arch/sh/kernel/vsyscall/vsyscall.c | 15 ---------------
 arch/tile/include/asm/page.h       |  6 ------
 arch/tile/kernel/vdso.c            | 15 ---------------
 arch/um/include/asm/page.h         |  5 +++++
 arch/x86/include/asm/page.h        |  1 -
 arch/x86/include/asm/page_64.h     |  2 ++
 arch/x86/um/asm/elf.h              |  1 -
 arch/x86/um/mem_64.c               | 15 ---------------
 arch/x86/vdso/vdso32-setup.c       | 19 +------------------
 include/linux/mm.h                 | 17 ++++++++++++-----
 mm/memory.c                        | 38 --------------------------------------
 mm/nommu.c                         |  5 -----
 21 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..992710f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -28,9 +28,6 @@
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_ARM64_64K_PAGES
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 50384fe..f630626 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -187,25 +187,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /*
- * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
- * Linux happy.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-/*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
 void update_vsyscall(struct timekeeper *tk)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index f1e1b2e..1f1bf14 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -231,4 +231,6 @@ get_order (unsigned long size)
 #define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)
 #define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)
 
+#define __HAVE_ARCH_GATE_AREA	1
+
 #endif /* _ASM_IA64_PAGE_H */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 25c3502..35efaa3 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -278,6 +278,32 @@ setup_gate (void)
 	ia64_patch_gate();
 }
 
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	gate_vma.vm_mm = NULL;
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
 void ia64_mmu_init(void *my_cpu_data)
 {
 	unsigned long pta, impl_va_bits;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32e4e21..26fe1ae 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT;
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ce74c33..f174351 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -840,19 +840,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 arch_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 114258e..7b2ac6e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -162,6 +162,4 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
-
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 6136490..0bbb7e0 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -316,18 +316,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 early_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 15d9703..fe20d14 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -186,11 +186,6 @@ typedef struct page *pgtable_t;
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-/* vDSO support */
-#ifdef CONFIG_VSYSCALL
-#define __HAVE_ARCH_GATE_AREA
-#endif
-
 /*
  * Some drivers need to perform DMA into kmalloc'ed buffers
  * and so we have to increase the kmalloc minalign for this.
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 5ca5797..ea2aa13 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -92,18 +92,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 6727680..a213a8d 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -39,12 +39,6 @@
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 
 /*
- * We do define AT_SYSINFO_EHDR to support vDSO,
- * but don't use the gate mechanism.
- */
-#define __HAVE_ARCH_GATE_AREA		1
-
-/*
  * If the Kconfig doesn't specify, set a maximum zone order that
  * is enough so that we can create huge pages from small pages given
  * the respective sizes of the two page types.  See <linux/mmzone.h>.
diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
index 1533af2..5bc51d7 100644
--- a/arch/tile/kernel/vdso.c
+++ b/arch/tile/kernel/vdso.c
@@ -121,21 +121,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
-
 int setup_vdso_pages(void)
 {
 	struct page **pagelist;
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 5ff53d9..71c5d13 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -119,4 +119,9 @@ extern unsigned long uml_physmem;
 #include <asm-generic/getorder.h>
 
 #endif	/* __ASSEMBLY__ */
+
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_GATE_AREA 1
+#endif
+
 #endif	/* __UM_PAGE_H */
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 775873d..802dde3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -70,7 +70,6 @@ extern bool __virt_addr_valid(unsigned long kaddr);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 
 #endif	/* __KERNEL__ */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 0f1ddee..f408caf 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,4 +39,6 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 0feee2f..25a1022 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -216,6 +216,5 @@ extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)
 
 #define SET_PERSONALITY(ex) do ; while(0)
-#define __HAVE_ARCH_GATE_AREA 1
 
 #endif
diff --git a/arch/x86/um/mem_64.c b/arch/x86/um/mem_64.c
index c6492e7..f8fecad 100644
--- a/arch/x86/um/mem_64.c
+++ b/arch/x86/um/mem_64.c
@@ -9,18 +9,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e4f7781..e904c27 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -115,23 +115,6 @@ static __init int ia32_binfmt_init(void)
 	return 0;
 }
 __initcall(ia32_binfmt_init);
-#endif
-
-#else  /* CONFIG_X86_32 */
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
+#endif /* CONFIG_SYSCTL */
 
 #endif	/* CONFIG_X86_64 */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..8981cc8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2014,13 +2014,20 @@ static inline bool kernel_page_present(struct page *page) { return true; }
 #endif /* CONFIG_HIBERNATION */
 #endif
 
+#ifdef __HAVE_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
-#ifdef	__HAVE_ARCH_GATE_AREA
-int in_gate_area_no_mm(unsigned long addr);
-int in_gate_area(struct mm_struct *mm, unsigned long addr);
+extern int in_gate_area_no_mm(unsigned long addr);
+extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
 #else
-int in_gate_area_no_mm(unsigned long addr);
-#define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
+static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
+static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
 #endif	/* __HAVE_ARCH_GATE_AREA */
 
 #ifdef CONFIG_SYSCTL
diff --git a/mm/memory.c b/mm/memory.c
index d67fd9f..099d234 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3399,44 +3399,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
 static int __follow_pte(struct mm_struct *mm, unsigned long address,
 		pte_t **ptepp, spinlock_t **ptlp)
 {
diff --git a/mm/nommu.c b/mm/nommu.c
index 4a852f6..a881d96 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1981,11 +1981,6 @@ error:
 	return -ENOMEM;
 }
 
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();
-- 
1.9.3

--
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[PATCH v2 09/10] arm64, ia64, ppc, s390, sh, tile, um, x86, mm: Remove default gate area

[Andy Lutomirski]

The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
64-bit UML, and x86_32 have their own code just to disable it.  arm,
32-bit UML, and x86_64 have gate areas, but they have their own
implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's
now possible to inline the gate_area functions in the default case.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390 at de.ibm.com
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Cc: x86 at kernel.org
Cc: linux-arch at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-ia64 at vger.kernel.org
Cc: linuxppc-dev at lists.ozlabs.org
Cc: linux-s390 at vger.kernel.org
Cc: linux-sh at vger.kernel.org
Cc: user-mode-linux-devel at lists.sourceforge.net
Cc: linux-mm at kvack.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/arm64/include/asm/page.h      |  3 ---
 arch/arm64/kernel/vdso.c           | 19 -------------------
 arch/ia64/include/asm/page.h       |  2 ++
 arch/ia64/mm/init.c                | 26 ++++++++++++++++++++++++++
 arch/powerpc/include/asm/page.h    |  3 ---
 arch/powerpc/kernel/vdso.c         | 16 ----------------
 arch/s390/include/asm/page.h       |  2 --
 arch/s390/kernel/vdso.c            | 15 ---------------
 arch/sh/include/asm/page.h         |  5 -----
 arch/sh/kernel/vsyscall/vsyscall.c | 15 ---------------
 arch/tile/include/asm/page.h       |  6 ------
 arch/tile/kernel/vdso.c            | 15 ---------------
 arch/um/include/asm/page.h         |  5 +++++
 arch/x86/include/asm/page.h        |  1 -
 arch/x86/include/asm/page_64.h     |  2 ++
 arch/x86/um/asm/elf.h              |  1 -
 arch/x86/um/mem_64.c               | 15 ---------------
 arch/x86/vdso/vdso32-setup.c       | 19 +------------------
 include/linux/mm.h                 | 17 ++++++++++++-----
 mm/memory.c                        | 38 --------------------------------------
 mm/nommu.c                         |  5 -----
 21 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..992710f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -28,9 +28,6 @@
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_ARM64_64K_PAGES
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 50384fe..f630626 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -187,25 +187,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /*
- * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
- * Linux happy.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-/*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
 void update_vsyscall(struct timekeeper *tk)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index f1e1b2e..1f1bf14 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -231,4 +231,6 @@ get_order (unsigned long size)
 #define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)
 #define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)
 
+#define __HAVE_ARCH_GATE_AREA	1
+
 #endif /* _ASM_IA64_PAGE_H */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 25c3502..35efaa3 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -278,6 +278,32 @@ setup_gate (void)
 	ia64_patch_gate();
 }
 
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	gate_vma.vm_mm = NULL;
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
 void ia64_mmu_init(void *my_cpu_data)
 {
 	unsigned long pta, impl_va_bits;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32e4e21..26fe1ae 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT;
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ce74c33..f174351 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -840,19 +840,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 arch_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 114258e..7b2ac6e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -162,6 +162,4 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
-
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 6136490..0bbb7e0 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -316,18 +316,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 early_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 15d9703..fe20d14 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -186,11 +186,6 @@ typedef struct page *pgtable_t;
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-/* vDSO support */
-#ifdef CONFIG_VSYSCALL
-#define __HAVE_ARCH_GATE_AREA
-#endif
-
 /*
  * Some drivers need to perform DMA into kmalloc'ed buffers
  * and so we have to increase the kmalloc minalign for this.
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 5ca5797..ea2aa13 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -92,18 +92,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 6727680..a213a8d 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -39,12 +39,6 @@
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 
 /*
- * We do define AT_SYSINFO_EHDR to support vDSO,
- * but don't use the gate mechanism.
- */
-#define __HAVE_ARCH_GATE_AREA		1
-
-/*
  * If the Kconfig doesn't specify, set a maximum zone order that
  * is enough so that we can create huge pages from small pages given
  * the respective sizes of the two page types.  See <linux/mmzone.h>.
diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
index 1533af2..5bc51d7 100644
--- a/arch/tile/kernel/vdso.c
+++ b/arch/tile/kernel/vdso.c
@@ -121,21 +121,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
-
 int setup_vdso_pages(void)
 {
 	struct page **pagelist;
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 5ff53d9..71c5d13 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -119,4 +119,9 @@ extern unsigned long uml_physmem;
 #include <asm-generic/getorder.h>
 
 #endif	/* __ASSEMBLY__ */
+
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_GATE_AREA 1
+#endif
+
 #endif	/* __UM_PAGE_H */
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 775873d..802dde3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -70,7 +70,6 @@ extern bool __virt_addr_valid(unsigned long kaddr);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 
 #endif	/* __KERNEL__ */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 0f1ddee..f408caf 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,4 +39,6 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 0feee2f..25a1022 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -216,6 +216,5 @@ extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)
 
 #define SET_PERSONALITY(ex) do ; while(0)
-#define __HAVE_ARCH_GATE_AREA 1
 
 #endif
diff --git a/arch/x86/um/mem_64.c b/arch/x86/um/mem_64.c
index c6492e7..f8fecad 100644
--- a/arch/x86/um/mem_64.c
+++ b/arch/x86/um/mem_64.c
@@ -9,18 +9,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e4f7781..e904c27 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -115,23 +115,6 @@ static __init int ia32_binfmt_init(void)
 	return 0;
 }
 __initcall(ia32_binfmt_init);
-#endif
-
-#else  /* CONFIG_X86_32 */
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
+#endif /* CONFIG_SYSCTL */
 
 #endif	/* CONFIG_X86_64 */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..8981cc8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2014,13 +2014,20 @@ static inline bool kernel_page_present(struct page *page) { return true; }
 #endif /* CONFIG_HIBERNATION */
 #endif
 
+#ifdef __HAVE_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
-#ifdef	__HAVE_ARCH_GATE_AREA
-int in_gate_area_no_mm(unsigned long addr);
-int in_gate_area(struct mm_struct *mm, unsigned long addr);
+extern int in_gate_area_no_mm(unsigned long addr);
+extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
 #else
-int in_gate_area_no_mm(unsigned long addr);
-#define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
+static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
+static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
 #endif	/* __HAVE_ARCH_GATE_AREA */
 
 #ifdef CONFIG_SYSCTL
diff --git a/mm/memory.c b/mm/memory.c
index d67fd9f..099d234 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3399,44 +3399,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
 static int __follow_pte(struct mm_struct *mm, unsigned long address,
 		pte_t **ptepp, spinlock_t **ptlp)
 {
diff --git a/mm/nommu.c b/mm/nommu.c
index 4a852f6..a881d96 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1981,11 +1981,6 @@ error:
 	return -ENOMEM;
 }
 
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();
-- 
1.9.3

[PATCH v2 09/10] arm64, ia64, ppc, s390, sh, tile, um, x86, mm: Remove default gate area

[Andy Lutomirski]

The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
64-bit UML, and x86_32 have their own code just to disable it.  arm,
32-bit UML, and x86_64 have gate areas, but they have their own
implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's
now possible to inline the gate_area functions in the default case.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/arm64/include/asm/page.h      |  3 ---
 arch/arm64/kernel/vdso.c           | 19 -------------------
 arch/ia64/include/asm/page.h       |  2 ++
 arch/ia64/mm/init.c                | 26 ++++++++++++++++++++++++++
 arch/powerpc/include/asm/page.h    |  3 ---
 arch/powerpc/kernel/vdso.c         | 16 ----------------
 arch/s390/include/asm/page.h       |  2 --
 arch/s390/kernel/vdso.c            | 15 ---------------
 arch/sh/include/asm/page.h         |  5 -----
 arch/sh/kernel/vsyscall/vsyscall.c | 15 ---------------
 arch/tile/include/asm/page.h       |  6 ------
 arch/tile/kernel/vdso.c            | 15 ---------------
 arch/um/include/asm/page.h         |  5 +++++
 arch/x86/include/asm/page.h        |  1 -
 arch/x86/include/asm/page_64.h     |  2 ++
 arch/x86/um/asm/elf.h              |  1 -
 arch/x86/um/mem_64.c               | 15 ---------------
 arch/x86/vdso/vdso32-setup.c       | 19 +------------------
 include/linux/mm.h                 | 17 ++++++++++++-----
 mm/memory.c                        | 38 --------------------------------------
 mm/nommu.c                         |  5 -----
 21 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..992710f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -28,9 +28,6 @@
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_ARM64_64K_PAGES
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 50384fe..f630626 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -187,25 +187,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /*
- * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
- * Linux happy.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-/*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
 void update_vsyscall(struct timekeeper *tk)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index f1e1b2e..1f1bf14 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -231,4 +231,6 @@ get_order (unsigned long size)
 #define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)
 #define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)
 
+#define __HAVE_ARCH_GATE_AREA	1
+
 #endif /* _ASM_IA64_PAGE_H */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 25c3502..35efaa3 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -278,6 +278,32 @@ setup_gate (void)
 	ia64_patch_gate();
 }
 
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	gate_vma.vm_mm = NULL;
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
 void ia64_mmu_init(void *my_cpu_data)
 {
 	unsigned long pta, impl_va_bits;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32e4e21..26fe1ae 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT;
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ce74c33..f174351 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -840,19 +840,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 arch_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 114258e..7b2ac6e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -162,6 +162,4 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
-
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 6136490..0bbb7e0 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -316,18 +316,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 early_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 15d9703..fe20d14 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -186,11 +186,6 @@ typedef struct page *pgtable_t;
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-/* vDSO support */
-#ifdef CONFIG_VSYSCALL
-#define __HAVE_ARCH_GATE_AREA
-#endif
-
 /*
  * Some drivers need to perform DMA into kmalloc'ed buffers
  * and so we have to increase the kmalloc minalign for this.
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 5ca5797..ea2aa13 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -92,18 +92,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 6727680..a213a8d 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -39,12 +39,6 @@
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 
 /*
- * We do define AT_SYSINFO_EHDR to support vDSO,
- * but don't use the gate mechanism.
- */
-#define __HAVE_ARCH_GATE_AREA		1
-
-/*
  * If the Kconfig doesn't specify, set a maximum zone order that
  * is enough so that we can create huge pages from small pages given
  * the respective sizes of the two page types.  See <linux/mmzone.h>.
diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
index 1533af2..5bc51d7 100644
--- a/arch/tile/kernel/vdso.c
+++ b/arch/tile/kernel/vdso.c
@@ -121,21 +121,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
-
 int setup_vdso_pages(void)
 {
 	struct page **pagelist;
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 5ff53d9..71c5d13 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -119,4 +119,9 @@ extern unsigned long uml_physmem;
 #include <asm-generic/getorder.h>
 
 #endif	/* __ASSEMBLY__ */
+
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_GATE_AREA 1
+#endif
+
 #endif	/* __UM_PAGE_H */
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 775873d..802dde3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -70,7 +70,6 @@ extern bool __virt_addr_valid(unsigned long kaddr);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 
 #endif	/* __KERNEL__ */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 0f1ddee..f408caf 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,4 +39,6 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 0feee2f..25a1022 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -216,6 +216,5 @@ extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)
 
 #define SET_PERSONALITY(ex) do ; while(0)
-#define __HAVE_ARCH_GATE_AREA 1
 
 #endif
diff --git a/arch/x86/um/mem_64.c b/arch/x86/um/mem_64.c
index c6492e7..f8fecad 100644
--- a/arch/x86/um/mem_64.c
+++ b/arch/x86/um/mem_64.c
@@ -9,18 +9,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e4f7781..e904c27 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -115,23 +115,6 @@ static __init int ia32_binfmt_init(void)
 	return 0;
 }
 __initcall(ia32_binfmt_init);
-#endif
-
-#else  /* CONFIG_X86_32 */
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
+#endif /* CONFIG_SYSCTL */
 
 #endif	/* CONFIG_X86_64 */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..8981cc8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2014,13 +2014,20 @@ static inline bool kernel_page_present(struct page *page) { return true; }
 #endif /* CONFIG_HIBERNATION */
 #endif
 
+#ifdef __HAVE_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
-#ifdef	__HAVE_ARCH_GATE_AREA
-int in_gate_area_no_mm(unsigned long addr);
-int in_gate_area(struct mm_struct *mm, unsigned long addr);
+extern int in_gate_area_no_mm(unsigned long addr);
+extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
 #else
-int in_gate_area_no_mm(unsigned long addr);
-#define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
+static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
+static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
 #endif	/* __HAVE_ARCH_GATE_AREA */
 
 #ifdef CONFIG_SYSCTL
diff --git a/mm/memory.c b/mm/memory.c
index d67fd9f..099d234 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3399,44 +3399,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
 static int __follow_pte(struct mm_struct *mm, unsigned long address,
 		pte_t **ptepp, spinlock_t **ptlp)
 {
diff --git a/mm/nommu.c b/mm/nommu.c
index 4a852f6..a881d96 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1981,11 +1981,6 @@ error:
 	return -ENOMEM;
 }
 
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();
-- 
1.9.3

[PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Andy Lutomirski]

The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
64-bit UML, and x86_32 have their own code just to disable it.  arm,
32-bit UML, and x86_64 have gate areas, but they have their own
implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's
now possible to inline the gate_area functions in the default case.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/arm64/include/asm/page.h      |  3 ---
 arch/arm64/kernel/vdso.c           | 19 -------------------
 arch/ia64/include/asm/page.h       |  2 ++
 arch/ia64/mm/init.c                | 26 ++++++++++++++++++++++++++
 arch/powerpc/include/asm/page.h    |  3 ---
 arch/powerpc/kernel/vdso.c         | 16 ----------------
 arch/s390/include/asm/page.h       |  2 --
 arch/s390/kernel/vdso.c            | 15 ---------------
 arch/sh/include/asm/page.h         |  5 -----
 arch/sh/kernel/vsyscall/vsyscall.c | 15 ---------------
 arch/tile/include/asm/page.h       |  6 ------
 arch/tile/kernel/vdso.c            | 15 ---------------
 arch/um/include/asm/page.h         |  5 +++++
 arch/x86/include/asm/page.h        |  1 -
 arch/x86/include/asm/page_64.h     |  2 ++
 arch/x86/um/asm/elf.h              |  1 -
 arch/x86/um/mem_64.c               | 15 ---------------
 arch/x86/vdso/vdso32-setup.c       | 19 +------------------
 include/linux/mm.h                 | 17 ++++++++++++-----
 mm/memory.c                        | 38 --------------------------------------
 mm/nommu.c                         |  5 -----
 21 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..992710f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -28,9 +28,6 @@
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_ARM64_64K_PAGES
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 50384fe..f630626 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -187,25 +187,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /*
- * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
- * Linux happy.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-/*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
 void update_vsyscall(struct timekeeper *tk)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index f1e1b2e..1f1bf14 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -231,4 +231,6 @@ get_order (unsigned long size)
 #define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)
 #define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)
 
+#define __HAVE_ARCH_GATE_AREA	1
+
 #endif /* _ASM_IA64_PAGE_H */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 25c3502..35efaa3 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -278,6 +278,32 @@ setup_gate (void)
 	ia64_patch_gate();
 }
 
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	gate_vma.vm_mm = NULL;
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
 void ia64_mmu_init(void *my_cpu_data)
 {
 	unsigned long pta, impl_va_bits;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32e4e21..26fe1ae 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT;
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ce74c33..f174351 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -840,19 +840,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 arch_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 114258e..7b2ac6e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -162,6 +162,4 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
-
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 6136490..0bbb7e0 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -316,18 +316,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 early_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 15d9703..fe20d14 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -186,11 +186,6 @@ typedef struct page *pgtable_t;
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-/* vDSO support */
-#ifdef CONFIG_VSYSCALL
-#define __HAVE_ARCH_GATE_AREA
-#endif
-
 /*
  * Some drivers need to perform DMA into kmalloc'ed buffers
  * and so we have to increase the kmalloc minalign for this.
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 5ca5797..ea2aa13 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -92,18 +92,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 6727680..a213a8d 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -39,12 +39,6 @@
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 
 /*
- * We do define AT_SYSINFO_EHDR to support vDSO,
- * but don't use the gate mechanism.
- */
-#define __HAVE_ARCH_GATE_AREA		1
-
-/*
  * If the Kconfig doesn't specify, set a maximum zone order that
  * is enough so that we can create huge pages from small pages given
  * the respective sizes of the two page types.  See <linux/mmzone.h>.
diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
index 1533af2..5bc51d7 100644
--- a/arch/tile/kernel/vdso.c
+++ b/arch/tile/kernel/vdso.c
@@ -121,21 +121,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
-
 int setup_vdso_pages(void)
 {
 	struct page **pagelist;
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 5ff53d9..71c5d13 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -119,4 +119,9 @@ extern unsigned long uml_physmem;
 #include <asm-generic/getorder.h>
 
 #endif	/* __ASSEMBLY__ */
+
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_GATE_AREA 1
+#endif
+
 #endif	/* __UM_PAGE_H */
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 775873d..802dde3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -70,7 +70,6 @@ extern bool __virt_addr_valid(unsigned long kaddr);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 
 #endif	/* __KERNEL__ */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 0f1ddee..f408caf 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,4 +39,6 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 0feee2f..25a1022 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -216,6 +216,5 @@ extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)
 
 #define SET_PERSONALITY(ex) do ; while(0)
-#define __HAVE_ARCH_GATE_AREA 1
 
 #endif
diff --git a/arch/x86/um/mem_64.c b/arch/x86/um/mem_64.c
index c6492e7..f8fecad 100644
--- a/arch/x86/um/mem_64.c
+++ b/arch/x86/um/mem_64.c
@@ -9,18 +9,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e4f7781..e904c27 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -115,23 +115,6 @@ static __init int ia32_binfmt_init(void)
 	return 0;
 }
 __initcall(ia32_binfmt_init);
-#endif
-
-#else  /* CONFIG_X86_32 */
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
+#endif /* CONFIG_SYSCTL */
 
 #endif	/* CONFIG_X86_64 */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..8981cc8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2014,13 +2014,20 @@ static inline bool kernel_page_present(struct page *page) { return true; }
 #endif /* CONFIG_HIBERNATION */
 #endif
 
+#ifdef __HAVE_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
-#ifdef	__HAVE_ARCH_GATE_AREA
-int in_gate_area_no_mm(unsigned long addr);
-int in_gate_area(struct mm_struct *mm, unsigned long addr);
+extern int in_gate_area_no_mm(unsigned long addr);
+extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
 #else
-int in_gate_area_no_mm(unsigned long addr);
-#define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
+static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
+static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
 #endif	/* __HAVE_ARCH_GATE_AREA */
 
 #ifdef CONFIG_SYSCTL
diff --git a/mm/memory.c b/mm/memory.c
index d67fd9f..099d234 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3399,44 +3399,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
 static int __follow_pte(struct mm_struct *mm, unsigned long address,
 		pte_t **ptepp, spinlock_t **ptlp)
 {
diff --git a/mm/nommu.c b/mm/nommu.c
index 4a852f6..a881d96 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1981,11 +1981,6 @@ error:
 	return -ENOMEM;
 }
 
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();
-- 
1.9.3

[PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Andy Lutomirski]

The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
64-bit UML, and x86_32 have their own code just to disable it.  arm,
32-bit UML, and x86_64 have gate areas, but they have their own
implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's
now possible to inline the gate_area functions in the default case.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/arm64/include/asm/page.h      |  3 ---
 arch/arm64/kernel/vdso.c           | 19 -------------------
 arch/ia64/include/asm/page.h       |  2 ++
 arch/ia64/mm/init.c                | 26 ++++++++++++++++++++++++++
 arch/powerpc/include/asm/page.h    |  3 ---
 arch/powerpc/kernel/vdso.c         | 16 ----------------
 arch/s390/include/asm/page.h       |  2 --
 arch/s390/kernel/vdso.c            | 15 ---------------
 arch/sh/include/asm/page.h         |  5 -----
 arch/sh/kernel/vsyscall/vsyscall.c | 15 ---------------
 arch/tile/include/asm/page.h       |  6 ------
 arch/tile/kernel/vdso.c            | 15 ---------------
 arch/um/include/asm/page.h         |  5 +++++
 arch/x86/include/asm/page.h        |  1 -
 arch/x86/include/asm/page_64.h     |  2 ++
 arch/x86/um/asm/elf.h              |  1 -
 arch/x86/um/mem_64.c               | 15 ---------------
 arch/x86/vdso/vdso32-setup.c       | 19 +------------------
 include/linux/mm.h                 | 17 ++++++++++++-----
 mm/memory.c                        | 38 --------------------------------------
 mm/nommu.c                         |  5 -----
 21 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..992710f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -28,9 +28,6 @@
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_ARM64_64K_PAGES
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 50384fe..f630626 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -187,25 +187,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /*
- * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
- * Linux happy.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-/*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
 void update_vsyscall(struct timekeeper *tk)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index f1e1b2e..1f1bf14 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -231,4 +231,6 @@ get_order (unsigned long size)
 #define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)
 #define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)
 
+#define __HAVE_ARCH_GATE_AREA	1
+
 #endif /* _ASM_IA64_PAGE_H */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 25c3502..35efaa3 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -278,6 +278,32 @@ setup_gate (void)
 	ia64_patch_gate();
 }
 
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	gate_vma.vm_mm = NULL;
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
 void ia64_mmu_init(void *my_cpu_data)
 {
 	unsigned long pta, impl_va_bits;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32e4e21..26fe1ae 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT;
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif
 
-/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
-#define __HAVE_ARCH_GATE_AREA		1
-
 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ce74c33..f174351 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -840,19 +840,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 arch_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 114258e..7b2ac6e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -162,6 +162,4 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
-
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 6136490..0bbb7e0 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -316,18 +316,3 @@ static int __init vdso_init(void)
 	return 0;
 }
 early_initcall(vdso_init);
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 15d9703..fe20d14 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -186,11 +186,6 @@ typedef struct page *pgtable_t;
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-/* vDSO support */
-#ifdef CONFIG_VSYSCALL
-#define __HAVE_ARCH_GATE_AREA
-#endif
-
 /*
  * Some drivers need to perform DMA into kmalloc'ed buffers
  * and so we have to increase the kmalloc minalign for this.
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index 5ca5797..ea2aa13 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -92,18 +92,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 6727680..a213a8d 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -39,12 +39,6 @@
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 
 /*
- * We do define AT_SYSINFO_EHDR to support vDSO,
- * but don't use the gate mechanism.
- */
-#define __HAVE_ARCH_GATE_AREA		1
-
-/*
  * If the Kconfig doesn't specify, set a maximum zone order that
  * is enough so that we can create huge pages from small pages given
  * the respective sizes of the two page types.  See <linux/mmzone.h>.
diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
index 1533af2..5bc51d7 100644
--- a/arch/tile/kernel/vdso.c
+++ b/arch/tile/kernel/vdso.c
@@ -121,21 +121,6 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long address)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long address)
-{
-	return 0;
-}
-
 int setup_vdso_pages(void)
 {
 	struct page **pagelist;
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 5ff53d9..71c5d13 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -119,4 +119,9 @@ extern unsigned long uml_physmem;
 #include <asm-generic/getorder.h>
 
 #endif	/* __ASSEMBLY__ */
+
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_GATE_AREA 1
+#endif
+
 #endif	/* __UM_PAGE_H */
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 775873d..802dde3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -70,7 +70,6 @@ extern bool __virt_addr_valid(unsigned long kaddr);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/getorder.h>
 
-#define __HAVE_ARCH_GATE_AREA 1
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 
 #endif	/* __KERNEL__ */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 0f1ddee..f408caf 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,4 +39,6 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 0feee2f..25a1022 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -216,6 +216,5 @@ extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)
 
 #define SET_PERSONALITY(ex) do ; while(0)
-#define __HAVE_ARCH_GATE_AREA 1
 
 #endif
diff --git a/arch/x86/um/mem_64.c b/arch/x86/um/mem_64.c
index c6492e7..f8fecad 100644
--- a/arch/x86/um/mem_64.c
+++ b/arch/x86/um/mem_64.c
@@ -9,18 +9,3 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 	return NULL;
 }
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e4f7781..e904c27 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -115,23 +115,6 @@ static __init int ia32_binfmt_init(void)
 	return 0;
 }
 __initcall(ia32_binfmt_init);
-#endif
-
-#else  /* CONFIG_X86_32 */
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return NULL;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
+#endif /* CONFIG_SYSCTL */
 
 #endif	/* CONFIG_X86_64 */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..8981cc8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2014,13 +2014,20 @@ static inline bool kernel_page_present(struct page *page) { return true; }
 #endif /* CONFIG_HIBERNATION */
 #endif
 
+#ifdef __HAVE_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
-#ifdef	__HAVE_ARCH_GATE_AREA
-int in_gate_area_no_mm(unsigned long addr);
-int in_gate_area(struct mm_struct *mm, unsigned long addr);
+extern int in_gate_area_no_mm(unsigned long addr);
+extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
 #else
-int in_gate_area_no_mm(unsigned long addr);
-#define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
+static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
+static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
 #endif	/* __HAVE_ARCH_GATE_AREA */
 
 #ifdef CONFIG_SYSCTL
diff --git a/mm/memory.c b/mm/memory.c
index d67fd9f..099d234 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3399,44 +3399,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
 static int __follow_pte(struct mm_struct *mm, unsigned long address,
 		pte_t **ptepp, spinlock_t **ptlp)
 {
diff --git a/mm/nommu.c b/mm/nommu.c
index 4a852f6..a881d96 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1981,11 +1981,6 @@ error:
 	return -ENOMEM;
 }
 
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return 0;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();
-- 
1.9.3

Re: [PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Will Deacon]

On Mon, Jun 30, 2014 at 10:53:20PM +0100, Andy Lutomirski wrote:
> The core mm code will provide a default gate area based on
> FIXADDR_USER_START and FIXADDR_USER_END if
> !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).
> 
> This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
> 64-bit UML, and x86_32 have their own code just to disable it.  arm,
> 32-bit UML, and x86_64 have gate areas, but they have their own
> implementations.
> 
> This gets rid of the default and moves the code into ia64.
> 
> This should save some code on architectures without a gate area: it's
> now possible to inline the gate_area functions in the default case.

For the arm64 bit:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
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Re: [PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Will Deacon]

On Mon, Jun 30, 2014 at 10:53:20PM +0100, Andy Lutomirski wrote:
> The core mm code will provide a default gate area based on
> FIXADDR_USER_START and FIXADDR_USER_END if
> !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).
> 
> This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
> 64-bit UML, and x86_32 have their own code just to disable it.  arm,
> 32-bit UML, and x86_64 have gate areas, but they have their own
> implementations.
> 
> This gets rid of the default and moves the code into ia64.
> 
> This should save some code on architectures without a gate area: it's
> now possible to inline the gate_area functions in the default case.

For the arm64 bit:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Will Deacon]

On Mon, Jun 30, 2014 at 10:53:20PM +0100, Andy Lutomirski wrote:
> The core mm code will provide a default gate area based on
> FIXADDR_USER_START and FIXADDR_USER_END if
> !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).
> 
> This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
> 64-bit UML, and x86_32 have their own code just to disable it.  arm,
> 32-bit UML, and x86_64 have gate areas, but they have their own
> implementations.
> 
> This gets rid of the default and moves the code into ia64.
> 
> This should save some code on architectures without a gate area: it's
> now possible to inline the gate_area functions in the default case.

For the arm64 bit:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

Re: [PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Will Deacon]

On Mon, Jun 30, 2014 at 10:53:20PM +0100, Andy Lutomirski wrote:
> The core mm code will provide a default gate area based on
> FIXADDR_USER_START and FIXADDR_USER_END if
> !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).
> 
> This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
> 64-bit UML, and x86_32 have their own code just to disable it.  arm,
> 32-bit UML, and x86_64 have gate areas, but they have their own
> implementations.
> 
> This gets rid of the default and moves the code into ia64.
> 
> This should save some code on architectures without a gate area: it's
> now possible to inline the gate_area functions in the default case.

For the arm64 bit:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

Re: [PATCH v2 09/10] arm64,ia64,ppc,s390,sh,tile,um,x86,mm: Remove default gate area

[Will Deacon]

On Mon, Jun 30, 2014 at 10:53:20PM +0100, Andy Lutomirski wrote:
> The core mm code will provide a default gate area based on
> FIXADDR_USER_START and FIXADDR_USER_END if
> !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).
> 
> This default is only useful for ia64.  arm64, ppc, s390, sh, tile,
> 64-bit UML, and x86_32 have their own code just to disable it.  arm,
> 32-bit UML, and x86_64 have gate areas, but they have their own
> implementations.
> 
> This gets rid of the default and moves the code into ia64.
> 
> This should save some code on architectures without a gate area: it's
> now possible to inline the gate_area functions in the default case.

For the arm64 bit:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 10/10] x86_64,vsyscall: Make vsyscall emulation configurable

[Andy Lutomirski]

This adds CONFIG_X86_VSYSCALL_EMULATION, guarded by CONFIG_EXPERT.
Turning it off completely disables vsyscall emulation, saving ~3.5k
for vsyscall_64.c, 4k for vsyscall_emu_64.S (the fake vsyscall
page), some tiny amount of core mm code that supports a gate area,
and possibly 4k for a wasted pagetable.  The latter is because the
vsyscall addresses are misaligned and fit poorly in the fixmap.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 arch/x86/Kconfig                | 18 ++++++++++++++++++
 arch/x86/include/asm/fixmap.h   |  2 ++
 arch/x86/include/asm/page_64.h  |  4 +++-
 arch/x86/include/asm/vsyscall.h |  8 ++++++++
 arch/x86/kernel/Makefile        |  3 +--
 arch/x86/kernel/setup.c         |  2 --
 arch/x86/xen/mmu.c              |  6 ++++--
 7 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a8f749e..a571cb4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -935,6 +935,24 @@ config X86_ESPFIX64
 	def_bool y
 	depends on X86_16BIT && X86_64
 
+config X86_VSYSCALL_EMULATION
+       bool "Enable vsyscall emulation" if EXPERT
+       default y
+       depends on X86_64
+       ---help---
+	 This enables emulation of the legacy vsyscall page.  Disabling
+	 it is roughly equivalent to booting with vsyscall=none, except
+	 that it will also disable the helpful warning if a program
+	 tries to use a vsyscall.  With this option set to N, offending
+	 program will just segfault, citing addresses of the form
+	 0xffffffffff600?00.
+
+         This option is required by many programs built before 2013, and
+	 care should be used even with newer programs if set to N.
+
+	 Disabling this option saves about 7K of kernel size and
+	 possibly 4K of additional runtime pagetable memory.
+
 config TOSHIBA
 	tristate "Toshiba Laptop support"
 	depends on X86_32
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index b0910f9..4568e6c 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -69,7 +69,9 @@ enum fixed_addresses {
 #ifdef CONFIG_X86_32
 	FIX_HOLE,
 #else
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
 	VSYSCALL_PAGE = (FIXADDR_TOP - VSYSCALL_ADDR) >> PAGE_SHIFT,
+#endif
 #ifdef CONFIG_PARAVIRT_CLOCK
 	PVCLOCK_FIXMAP_BEGIN,
 	PVCLOCK_FIXMAP_END = PVCLOCK_FIXMAP_BEGIN+PVCLOCK_VSYSCALL_NR_PAGES-1,
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index f408caf..b3bebf9 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -39,6 +39,8 @@ void copy_page(void *to, void *from);
 
 #endif	/* !__ASSEMBLY__ */
 
-#define __HAVE_ARCH_GATE_AREA 1
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
+# define __HAVE_ARCH_GATE_AREA 1
+#endif
 
 #endif /* _ASM_X86_PAGE_64_H */
diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h
index 34f7d88..6ba66ee 100644
--- a/arch/x86/include/asm/vsyscall.h
+++ b/arch/x86/include/asm/vsyscall.h
@@ -4,6 +4,7 @@
 #include <linux/seqlock.h>
 #include <uapi/asm/vsyscall.h>
 
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
 extern void map_vsyscall(void);
 
 /*
@@ -11,5 +12,12 @@ extern void map_vsyscall(void);
  * Returns true if handled.
  */
 extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address);
+#else
+static inline void map_vsyscall(void) {}
+static inline bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
+{
+	return false;
+}
+#endif
 
 #endif /* _ASM_X86_VSYSCALL_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 047f9ff..2f71845 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -28,8 +28,7 @@ obj-$(CONFIG_X86_32)	+= i386_ksyms_32.o
 obj-$(CONFIG_X86_64)	+= sys_x86_64.o x8664_ksyms_64.o
 obj-$(CONFIG_X86_64)	+= mcount_64.o
 obj-y			+= syscall_$(BITS).o vsyscall_gtod.o
-obj-$(CONFIG_X86_64)	+= vsyscall_64.o
-obj-$(CONFIG_X86_64)	+= vsyscall_emu_64.o
+obj-$(CONFIG_X86_VSYSCALL_EMULATION)	+= vsyscall_64.o vsyscall_emu_64.o
 obj-$(CONFIG_X86_ESPFIX64)	+= espfix_64.o
 obj-$(CONFIG_SYSFS)	+= ksysfs.o
 obj-y			+= bootflag.o e820.o
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 78a0e62..86eabe8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1181,9 +1181,7 @@ void __init setup_arch(char **cmdline_p)
 
 	tboot_probe();
 
-#ifdef CONFIG_X86_64
 	map_vsyscall();
-#endif
 
 	generic_apic_probe();
 
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index e8a1201..8e4a96b 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1493,11 +1493,13 @@ static int xen_pgd_alloc(struct mm_struct *mm)
 		user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 		page->private = (unsigned long)user_pgd;
 
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
 		if (user_pgd != NULL) {
 			user_pgd[pgd_index(VSYSCALL_ADDR)] =
 				__pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
 			ret = 0;
 		}
+#endif
 
 		BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
 	}
@@ -2061,7 +2063,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 # ifdef CONFIG_HIGHMEM
 	case FIX_KMAP_BEGIN ... FIX_KMAP_END:
 # endif
-#else
+#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
 	case VSYSCALL_PAGE:
 #endif
 	case FIX_TEXT_POKE0:
@@ -2100,7 +2102,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 
 	__native_set_fixmap(idx, pte);
 
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
 	/* Replicate changes to map the vsyscall page into the user
 	   pagetable vsyscall mapping. */
 	if (idx == VSYSCALL_PAGE) {
-- 
1.9.3