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ftrace: store mcount address in rec->ip

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Record the address of the mcount call-site. Currently all archs except sparc64
record the address of the instruction following the mcount call-site. Some
general cleanups are entailed. Storing mcount addresses in rec->ip enables
looking them up in the kprobe hash table later on to check if they're kprobe'd.

Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Cc: davem@davemloft.net
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Abhishek Sagar
2008-06-21 23:47:27 +05:30
committed by Ingo Molnar
parent f34bfb1bee
commit 395a59d0f8
19 changed files with 111 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
arch/arm/kernel/armksyms.c
View File

@@ -18,6 +18,7 @@
#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ftrace.h>
/*
* libgcc functions - functions that are used internally by the
@@ -48,11 +49,6 @@ extern void __aeabi_ulcmp(void);
extern void fpundefinstr(void);
extern void fp_enter(void);
#ifdef CONFIG_FTRACE
extern void mcount(void);
EXPORT_SYMBOL(mcount);
#endif
/*
* This has a special calling convention; it doesn't
* modify any of the usual registers, except for LR.
@@ -186,3 +182,7 @@ EXPORT_SYMBOL(_find_next_bit_be);
#endif
EXPORT_SYMBOL(copy_page);
#ifdef CONFIG_FTRACE
EXPORT_SYMBOL(mcount);
#endif

4
arch/arm/kernel/entry-common.S
View File

@@ -9,6 +9,7 @@
*/
#include <asm/unistd.h>
#include <asm/ftrace.h>
#include <asm/arch/entry-macro.S>
#include "entry-header.S"
@@ -104,6 +105,7 @@ ENTRY(ret_from_fork)
ENTRY(mcount)
stmdb sp!, {r0-r3, lr}
mov r0, lr
sub r0, r0, #MCOUNT_INSN_SIZE
.globl mcount_call
mcount_call:
@@ -114,6 +116,7 @@ ENTRY(ftrace_caller)
stmdb sp!, {r0-r3, lr}
ldr r1, [fp, #-4]
mov r0, lr
sub r0, r0, #MCOUNT_INSN_SIZE
.globl ftrace_call
ftrace_call:
@@ -134,6 +137,7 @@ ENTRY(mcount)
trace:
ldr r1, [fp, #-4]
mov r0, lr
sub r0, r0, #MCOUNT_INSN_SIZE
mov lr, pc
mov pc, r2
ldmia sp!, {r0-r3, pc}

18
arch/arm/kernel/ftrace.c
View File

@@ -12,9 +12,10 @@
*/
#include <linux/ftrace.h>
#include <asm/cacheflush.h>
#define INSN_SIZE 4
#include <asm/cacheflush.h>
#include <asm/ftrace.h>
#define PC_OFFSET 8
#define BL_OPCODE 0xeb000000
#define BL_OFFSET_MASK 0x00ffffff
@@ -32,10 +33,10 @@ unsigned char *ftrace_call_replace(unsigned long pc, unsigned long addr)
{
long offset;
offset = (long)addr - (long)(pc - INSN_SIZE + PC_OFFSET);
offset = (long)addr - (long)(pc + PC_OFFSET);
if (unlikely(offset < -33554432 || offset > 33554428)) {
/* Can't generate branches that far (from ARM ARM). Ftrace
* doesn't generate branches outside of core kernel text.
* doesn't generate branches outside of kernel text.
*/
WARN_ON_ONCE(1);
return NULL;
@@ -52,7 +53,6 @@ int ftrace_modify_code(unsigned long pc, unsigned char *old_code,
old = *(unsigned long *)old_code;
new = *(unsigned long *)new_code;
pc -= INSN_SIZE;
__asm__ __volatile__ (
"1: ldr %1, [%2] \n"
@@ -77,7 +77,7 @@ int ftrace_modify_code(unsigned long pc, unsigned char *old_code,
: "memory");
if (!err && (replaced == old))
flush_icache_range(pc, pc + INSN_SIZE);
flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
return err;
}
@@ -89,8 +89,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
unsigned char *new;
pc = (unsigned long)&ftrace_call;
pc += INSN_SIZE;
memcpy(&old, &ftrace_call, INSN_SIZE);
memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(pc, (unsigned long)func);
ret = ftrace_modify_code(pc, (unsigned char *)&old, new);
return ret;
@@ -103,8 +102,7 @@ int ftrace_mcount_set(unsigned long *data)
unsigned char *new;
pc = (unsigned long)&mcount_call;
pc += INSN_SIZE;
memcpy(&old, &mcount_call, INSN_SIZE);
memcpy(&old, &mcount_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(pc, *addr);
*addr = ftrace_modify_code(pc, (unsigned char *)&old, new);
return 0;