* [PATCH/RFC 2/4] arch specific probe_kernel_write() implementation
2009-06-02 10:53 [PATCH/RFC 0/4] Dynamic ftrace support for s390 Heiko Carstens
2009-06-02 10:53 ` [PATCH/RFC 1/4] maccess: add weak attribute to probe_kernel_write Heiko Carstens
@ 2009-06-02 10:53 ` Heiko Carstens
2009-06-02 10:53 ` [PATCH/RFC 3/4] kprobes: use probe_kernel_write Heiko Carstens
2009-06-02 10:53 ` [PATCH/RFC 4/4] add dynamic ftrace support Heiko Carstens
3 siblings, 0 replies; 6+ messages in thread
From: Heiko Carstens @ 2009-06-02 10:53 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Ingo Molnar, Steven Rostedt, Frederic Weisbecker,
Martin Schwidefsky, Heiko Carstens
[-- Attachment #1: 201-probe_kernel_write-s390.diff --]
[-- Type: text/plain, Size: 2846 bytes --]
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Add an s390 specific probe_kernel_write() function which allows to
write to the kernel text segment even if write protection is enabled.
This is implemented using the lra (load real address) and stura (store
using real address) instructions.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---
arch/s390/mm/Makefile | 2 -
arch/s390/mm/maccess.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+), 1 deletion(-)
diff -urpN linux-2.6/arch/s390/mm/maccess.c linux-2.6-patched/arch/s390/mm/maccess.c
--- linux-2.6/arch/s390/mm/maccess.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6-patched/arch/s390/mm/maccess.c 2009-06-02 10:40:04.000000000 +0200
@@ -0,0 +1,61 @@
+/*
+ * Access kernel memory without faulting -- s390 specific implementation.
+ *
+ * Copyright IBM Corp. 2009
+ *
+ * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ *
+ */
+
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <asm/system.h>
+
+/*
+ * This function writes to kernel memory bypassing DAT and possible
+ * write protection. It copies one to four bytes from src to dst
+ * using the stura instruction.
+ * Returns the number of bytes copied or -EFAULT.
+ */
+static long probe_kernel_write_odd(void *dst, void *src, size_t size)
+{
+ unsigned long count, aligned;
+ int offset, mask;
+ int rc = -EFAULT;
+
+ aligned = (unsigned long) dst & ~3UL;
+ offset = (unsigned long) dst & 3;
+ count = min_t(unsigned long, 4 - offset, size);
+ mask = (0xf << (4 - count)) & 0xf;
+ mask >>= offset;
+ asm volatile(
+ " bras 1,0f\n"
+ " icm 0,0,0(%3)\n"
+ "0: l 0,0(%1)\n"
+ " lra %1,0(%1)\n"
+ "1: ex %2,0(1)\n"
+ "2: stura 0,%1\n"
+ " la %0,0\n"
+ "3:\n"
+ EX_TABLE(0b,3b) EX_TABLE(1b,3b) EX_TABLE(2b,3b)
+ : "+d" (rc), "+a" (aligned)
+ : "a" (mask), "a" (src) : "cc", "memory", "0", "1");
+ return rc ? rc : count;
+}
+
+long probe_kernel_write(void *dst, void *src, size_t size)
+{
+ long copied = 0;
+
+ while (size) {
+ copied = probe_kernel_write_odd(dst, src, size);
+ if (copied < 0)
+ break;
+ dst += copied;
+ src += copied;
+ size -= copied;
+ }
+ return copied < 0 ? -EFAULT : 0;
+}
diff -urpN linux-2.6/arch/s390/mm/Makefile linux-2.6-patched/arch/s390/mm/Makefile
--- linux-2.6/arch/s390/mm/Makefile 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6-patched/arch/s390/mm/Makefile 2009-06-02 10:40:04.000000000 +0200
@@ -2,7 +2,7 @@
# Makefile for the linux s390-specific parts of the memory manager.
#
-obj-y := init.o fault.o extmem.o mmap.o vmem.o pgtable.o
+obj-y := init.o fault.o extmem.o mmap.o vmem.o pgtable.o maccess.o
obj-$(CONFIG_CMM) += cmm.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_PAGE_STATES) += page-states.o
--
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH/RFC 4/4] add dynamic ftrace support
2009-06-02 10:53 [PATCH/RFC 0/4] Dynamic ftrace support for s390 Heiko Carstens
` (2 preceding siblings ...)
2009-06-02 10:53 ` [PATCH/RFC 3/4] kprobes: use probe_kernel_write Heiko Carstens
@ 2009-06-02 10:53 ` Heiko Carstens
2009-06-02 15:28 ` Steven Rostedt
3 siblings, 1 reply; 6+ messages in thread
From: Heiko Carstens @ 2009-06-02 10:53 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Ingo Molnar, Steven Rostedt, Frederic Weisbecker,
Martin Schwidefsky, Heiko Carstens
[-- Attachment #1: 203-dynamic-ftrace.diff --]
[-- Type: text/plain, Size: 12489 bytes --]
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Dynamic ftrace support for s390.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---
arch/s390/Kconfig | 2
arch/s390/include/asm/ftrace.h | 19 +++++
arch/s390/include/asm/lowcore.h | 8 +-
arch/s390/kernel/Makefile | 5 +
arch/s390/kernel/early.c | 4 +
arch/s390/kernel/ftrace.c | 132 ++++++++++++++++++++++++++++++++++++++++
arch/s390/kernel/mcount.S | 119 +++++++++++++++++++++++++++---------
arch/s390/kernel/setup.c | 2
arch/s390/kernel/smp.c | 1
scripts/recordmcount.pl | 13 +++
10 files changed, 276 insertions(+), 29 deletions(-)
Index: linux-2.6/arch/s390/include/asm/ftrace.h
===================================================================
--- linux-2.6.orig/arch/s390/include/asm/ftrace.h
+++ linux-2.6/arch/s390/include/asm/ftrace.h
@@ -2,7 +2,26 @@
#define _ASM_S390_FTRACE_H
#ifndef __ASSEMBLY__
+
extern void _mcount(void);
+extern unsigned long ftrace_dyn_func;
+
+struct dyn_arch_ftrace { };
+
+#define MCOUNT_ADDR ((long)_mcount)
+
+#ifdef CONFIG_64BIT
+#define MCOUNT_INSN_SIZE 24
+#define MCOUNT_OFFSET 14
+#else
+#define MCOUNT_INSN_SIZE 30
+#define MCOUNT_OFFSET 8
#endif
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ return addr - MCOUNT_OFFSET;
+}
+
+#endif /* __ASSEMBLY__ */
#endif /* _ASM_S390_FTRACE_H */
Index: linux-2.6/arch/s390/include/asm/lowcore.h
===================================================================
--- linux-2.6.orig/arch/s390/include/asm/lowcore.h
+++ linux-2.6/arch/s390/include/asm/lowcore.h
@@ -67,6 +67,7 @@
#define __LC_CPUID 0x02b0
#define __LC_INT_CLOCK 0x02c8
#define __LC_MACHINE_FLAGS 0x02d8
+#define __LC_FTRACE_FUNC 0x02dc
#define __LC_IRB 0x0300
#define __LC_PFAULT_INTPARM 0x0080
#define __LC_CPU_TIMER_SAVE_AREA 0x00d8
@@ -112,6 +113,7 @@
#define __LC_INT_CLOCK 0x0340
#define __LC_VDSO_PER_CPU 0x0350
#define __LC_MACHINE_FLAGS 0x0358
+#define __LC_FTRACE_FUNC 0x0360
#define __LC_IRB 0x0380
#define __LC_PASTE 0x03c0
#define __LC_PFAULT_INTPARM 0x11b8
@@ -280,7 +282,8 @@ struct _lowcore
__u64 int_clock; /* 0x02c8 */
__u64 clock_comparator; /* 0x02d0 */
__u32 machine_flags; /* 0x02d8 */
- __u8 pad_0x02dc[0x0300-0x02dc]; /* 0x02dc */
+ __u32 ftrace_func; /* 0x02dc */
+ __u8 pad_0x02f0[0x0300-0x02f0]; /* 0x02f0 */
/* Interrupt response block */
__u8 irb[64]; /* 0x0300 */
@@ -385,7 +388,8 @@ struct _lowcore
__u64 clock_comparator; /* 0x0348 */
__u64 vdso_per_cpu_data; /* 0x0350 */
__u64 machine_flags; /* 0x0358 */
- __u8 pad_0x0360[0x0380-0x0360]; /* 0x0360 */
+ __u64 ftrace_func; /* 0x0360 */
+ __u8 pad_0x0368[0x0380-0x0368]; /* 0x0368 */
/* Interrupt response block. */
__u8 irb[64]; /* 0x0380 */
Index: linux-2.6/arch/s390/Kconfig
===================================================================
--- linux-2.6.orig/arch/s390/Kconfig
+++ linux-2.6/arch/s390/Kconfig
@@ -82,6 +82,8 @@ config S390
select USE_GENERIC_SMP_HELPERS if SMP
select HAVE_SYSCALL_WRAPPERS
select HAVE_FUNCTION_TRACER
+ select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_DYNAMIC_FTRACE
select HAVE_DEFAULT_NO_SPIN_MUTEXES
select HAVE_OPROFILE
select HAVE_KPROBES
Index: linux-2.6/arch/s390/kernel/early.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/early.c
+++ linux-2.6/arch/s390/kernel/early.c
@@ -11,6 +11,7 @@
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ctype.h>
+#include <linux/ftrace.h>
#include <linux/lockdep.h>
#include <linux/module.h>
#include <linux/pfn.h>
@@ -410,5 +411,8 @@ void __init startup_init(void)
sclp_facilities_detect();
detect_memory_layout(memory_chunk);
S390_lowcore.machine_flags = machine_flags;
+#ifdef CONFIG_DYNAMIC_FTRACE
+ S390_lowcore.ftrace_func = (unsigned long)ftrace_caller;
+#endif
lockdep_on();
}
Index: linux-2.6/arch/s390/kernel/ftrace.c
===================================================================
--- /dev/null
+++ linux-2.6/arch/s390/kernel/ftrace.c
@@ -0,0 +1,132 @@
+/*
+ * Dynamic function tracer architecture backend.
+ *
+ * Copyright IBM Corp. 2009
+ *
+ * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ *
+ */
+
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <asm/lowcore.h>
+
+void ftrace_disable_code(void);
+void ftrace_call_code(void);
+void ftrace_nop_code(void);
+
+#define FTRACE_INSN_SIZE 4
+
+#ifdef CONFIG_64BIT
+
+asm(
+ " .align 4\n"
+ "ftrace_disable_code:\n"
+ " j 0f\n"
+ " .word 0x0024\n"
+ " lg %r1,"__stringify(__LC_FTRACE_FUNC)"\n"
+ " basr %r14,%r1\n"
+ " lg %r14,8(15)\n"
+ " lgr %r0,%r0\n"
+ "0:\n");
+
+asm(
+ " .align 4\n"
+ "ftrace_nop_code:\n"
+ " j .+"__stringify(MCOUNT_INSN_SIZE)"\n");
+
+asm(
+ " .align 4\n"
+ "ftrace_call_code:\n"
+ " stg %r14,8(%r15)\n");
+
+#else /* CONFIG_64BIT */
+
+asm(
+ " .align 4\n"
+ "ftrace_disable_code:\n"
+ " j 0f\n"
+ " l %r1,"__stringify(__LC_FTRACE_FUNC)"\n"
+ " basr %r14,%r1\n"
+ " l %r14,4(%r15)\n"
+ " j 0f\n"
+ " bcr 0,%r7\n"
+ " bcr 0,%r7\n"
+ " bcr 0,%r7\n"
+ " bcr 0,%r7\n"
+ " bcr 0,%r7\n"
+ " bcr 0,%r7\n"
+ "0:\n");
+
+asm(
+ " .align 4\n"
+ "ftrace_nop_code:\n"
+ " j .+"__stringify(MCOUNT_INSN_SIZE)"\n");
+
+asm(
+ " .align 4\n"
+ "ftrace_call_code:\n"
+ " st %r14,4(%r15)\n");
+
+#endif /* CONFIG_64BIT */
+
+static int ftrace_modify_code(unsigned long ip,
+ void *old_code, int old_size,
+ void *new_code, int new_size)
+{
+ unsigned char replaced[MCOUNT_INSN_SIZE];
+
+ /*
+ * Note: Due to modules code can disappear and change.
+ * We need to protect against faulting as well as code
+ * changing. We do this by using the probe_kernel_*
+ * functions.
+ * This however is just a simple sanity check.
+ */
+ if (probe_kernel_read(replaced, (void *)ip, old_size))
+ return -EFAULT;
+ if (memcmp(replaced, old_code, old_size) != 0)
+ return -EINVAL;
+ if (probe_kernel_write((void *)ip, new_code, new_size))
+ return -EPERM;
+ return 0;
+}
+
+static int ftrace_make_initial_nop(struct module *mod, struct dyn_ftrace *rec,
+ unsigned long addr)
+{
+ return ftrace_modify_code(rec->ip,
+ ftrace_call_code, FTRACE_INSN_SIZE,
+ ftrace_disable_code, MCOUNT_INSN_SIZE);
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
+ unsigned long addr)
+{
+ if (addr == MCOUNT_ADDR)
+ return ftrace_make_initial_nop(mod, rec, addr);
+ return ftrace_modify_code(rec->ip,
+ ftrace_call_code, FTRACE_INSN_SIZE,
+ ftrace_nop_code, FTRACE_INSN_SIZE);
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ return ftrace_modify_code(rec->ip,
+ ftrace_nop_code, FTRACE_INSN_SIZE,
+ ftrace_call_code, FTRACE_INSN_SIZE);
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ ftrace_dyn_func = (unsigned long)func;
+ return 0;
+}
+
+int __init ftrace_dyn_arch_init(void *data)
+{
+ *(unsigned long *)data = 0;
+ return 0;
+}
Index: linux-2.6/arch/s390/kernel/Makefile
===================================================================
--- linux-2.6.orig/arch/s390/kernel/Makefile
+++ linux-2.6/arch/s390/kernel/Makefile
@@ -7,6 +7,10 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_early.o = -pg
endif
+ifdef CONFIG_DYNAMIC_FTRACE
+CFLAGS_REMOVE_ftrace.o = -pg
+endif
+
#
# Passing null pointers is ok for smp code, since we access the lowcore here.
#
@@ -41,6 +45,7 @@ obj-$(CONFIG_COMPAT) += compat_linux.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_FUNCTION_TRACER) += mcount.o
+obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
# Kexec part
S390_KEXEC_OBJS := machine_kexec.o crash.o
Index: linux-2.6/arch/s390/kernel/mcount.S
===================================================================
--- linux-2.6.orig/arch/s390/kernel/mcount.S
+++ linux-2.6/arch/s390/kernel/mcount.S
@@ -1,5 +1,5 @@
/*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
*
@@ -7,36 +7,46 @@
#include <asm/asm-offsets.h>
-#ifndef CONFIG_64BIT
-.globl _mcount
+ .globl ftrace_stub
+ftrace_stub:
+ br %r14
+
+#ifdef CONFIG_64BIT
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+ .globl _mcount
_mcount:
- stm %r0,%r5,8(%r15)
- st %r14,56(%r15)
- lr %r1,%r15
- ahi %r15,-96
- l %r3,100(%r15)
- la %r2,0(%r14)
- st %r1,__SF_BACKCHAIN(%r15)
- la %r3,0(%r3)
- bras %r14,0f
- .long ftrace_trace_function
-0: l %r14,0(%r14)
- l %r14,0(%r14)
- basr %r14,%r14
- ahi %r15,96
- lm %r0,%r5,8(%r15)
- l %r14,56(%r15)
br %r14
-.globl ftrace_stub
-ftrace_stub:
+ .globl ftrace_caller
+ftrace_caller:
+ stmg %r2,%r5,32(%r15)
+ stg %r14,112(%r15)
+ lgr %r1,%r15
+ aghi %r15,-160
+ stg %r1,__SF_BACKCHAIN(%r15)
+ lgr %r2,%r14
+ lg %r3,168(%r15)
+ larl %r14,ftrace_dyn_func
+ lg %r14,0(%r14)
+ basr %r14,%r14
+ aghi %r15,160
+ lmg %r2,%r5,32(%r15)
+ lg %r14,112(%r15)
br %r14
-#else /* CONFIG_64BIT */
+ .data
+ .globl ftrace_dyn_func
+ftrace_dyn_func:
+ .quad ftrace_stub
+ .previous
+
+#else /* CONFIG_DYNAMIC_FTRACE */
-.globl _mcount
+ .globl _mcount
_mcount:
- stmg %r0,%r5,16(%r15)
+ stmg %r2,%r5,32(%r15)
stg %r14,112(%r15)
lgr %r1,%r15
aghi %r15,-160
@@ -47,12 +57,67 @@ _mcount:
lg %r14,0(%r14)
basr %r14,%r14
aghi %r15,160
- lmg %r0,%r5,16(%r15)
+ lmg %r2,%r5,32(%r15)
lg %r14,112(%r15)
br %r14
-.globl ftrace_stub
-ftrace_stub:
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#else /* CONFIG_64BIT */
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+ .globl _mcount
+_mcount:
+ br %r14
+
+ .globl ftrace_caller
+ftrace_caller:
+ stm %r2,%r5,16(%r15)
+ st %r14,56(%r15)
+ lr %r1,%r15
+ ahi %r15,-96
+ l %r3,100(%r15)
+ la %r2,0(%r14)
+ st %r1,__SF_BACKCHAIN(%r15)
+ la %r3,0(%r3)
+ bras %r14,0f
+ .long ftrace_dyn_func
+0: l %r14,0(%r14)
+ l %r14,0(%r14)
+ basr %r14,%r14
+ ahi %r15,96
+ lm %r2,%r5,16(%r15)
+ l %r14,56(%r15)
+ br %r14
+
+ .data
+ .globl ftrace_dyn_func
+ftrace_dyn_func:
+ .long ftrace_stub
+ .previous
+
+#else /* CONFIG_DYNAMIC_FTRACE */
+
+ .globl _mcount
+_mcount:
+ stm %r2,%r5,16(%r15)
+ st %r14,56(%r15)
+ lr %r1,%r15
+ ahi %r15,-96
+ l %r3,100(%r15)
+ la %r2,0(%r14)
+ st %r1,__SF_BACKCHAIN(%r15)
+ la %r3,0(%r3)
+ bras %r14,0f
+ .long ftrace_trace_function
+0: l %r14,0(%r14)
+ l %r14,0(%r14)
+ basr %r14,%r14
+ ahi %r15,96
+ lm %r2,%r5,16(%r15)
+ l %r14,56(%r15)
br %r14
+#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_64BIT */
Index: linux-2.6/arch/s390/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/setup.c
+++ linux-2.6/arch/s390/kernel/setup.c
@@ -42,6 +42,7 @@
#include <linux/ctype.h>
#include <linux/reboot.h>
#include <linux/topology.h>
+#include <linux/ftrace.h>
#include <asm/ipl.h>
#include <asm/uaccess.h>
@@ -442,6 +443,7 @@ setup_lowcore(void)
lc->steal_timer = S390_lowcore.steal_timer;
lc->last_update_timer = S390_lowcore.last_update_timer;
lc->last_update_clock = S390_lowcore.last_update_clock;
+ lc->ftrace_func = S390_lowcore.ftrace_func;
set_prefix((u32)(unsigned long) lc);
lowcore_ptr[0] = lc;
}
Index: linux-2.6/arch/s390/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/smp.c
+++ linux-2.6/arch/s390/kernel/smp.c
@@ -572,6 +572,7 @@ int __cpuinit __cpu_up(unsigned int cpu)
cpu_lowcore->cpu_nr = cpu;
cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
cpu_lowcore->machine_flags = S390_lowcore.machine_flags;
+ cpu_lowcore->ftrace_func = S390_lowcore.ftrace_func;
eieio();
while (signal_processor(cpu, sigp_restart) == sigp_busy)
Index: linux-2.6/scripts/recordmcount.pl
===================================================================
--- linux-2.6.orig/scripts/recordmcount.pl
+++ linux-2.6/scripts/recordmcount.pl
@@ -185,6 +185,19 @@ if ($arch eq "x86_64") {
$objcopy .= " -O elf32-i386";
$cc .= " -m32";
+} elsif ($arch eq "s390" && $bits == 32) {
+ $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_32\\s+_mcount\$";
+ $alignment = 4;
+ $ld .= " -m elf_s390";
+ $cc .= " -m31";
+
+} elsif ($arch eq "s390" && $bits == 64) {
+ $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$";
+ $alignment = 8;
+ $type = ".quad";
+ $ld .= " -m elf64_s390";
+ $cc .= " -m64";
+
} elsif ($arch eq "sh") {
$alignment = 2;
--
^ permalink raw reply [flat|nested] 6+ messages in thread