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Merge branch 'sh/ftrace' of git://github.com/mfleming/linux-2.6

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This commit is contained in:
Paul Mundt
2009-06-12 01:12:44 +03:00
parent 512626a04e 9e28c46b7d
commit cf64c800f0
1 changed files with 30 additions and 30 deletions
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60
arch/sh/kernel/ftrace.c
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@@ -1,5 +1,5 @@
/* /*
* Copyright (C) 2008 Matt Fleming <mjf@gentoo.org> * Copyright (C) 2008 Matt Fleming <matt@console-pimps.org>
* Copyright (C) 2008 Paul Mundt <lethal@linux-sh.org> * Copyright (C) 2008 Paul Mundt <lethal@linux-sh.org>
* *
* Code for replacing ftrace calls with jumps. * Code for replacing ftrace calls with jumps.
@@ -19,30 +19,37 @@
#include <asm/ftrace.h> #include <asm/ftrace.h>
#include <asm/cacheflush.h> #include <asm/cacheflush.h>
static unsigned char ftrace_nop[] = {
0x09, 0x00, /* nop */
0x09, 0x00, /* nop */
};
static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE]; static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE];
unsigned char *ftrace_nop_replace(void) static unsigned char ftrace_nop[4];
/*
* If we're trying to nop out a call to a function, we instead
* place a call to the address after the memory table.
*
* 8c011060 <a>:
* 8c011060: 02 d1 mov.l 8c01106c <a+0xc>,r1
* 8c011062: 22 4f sts.l pr,@-r15
* 8c011064: 02 c7 mova 8c011070 <a+0x10>,r0
* 8c011066: 2b 41 jmp @r1
* 8c011068: 2a 40 lds r0,pr
* 8c01106a: 09 00 nop
* 8c01106c: 68 24 .word 0x2468 <--- ip
* 8c01106e: 1d 8c .word 0x8c1d
* 8c011070: 26 4f lds.l @r15+,pr <--- ip + MCOUNT_INSN_SIZE
*
* We write 0x8c011070 to 0x8c01106c so that on entry to a() we branch
* past the _mcount call and continue executing code like normal.
*/
static unsigned char *ftrace_nop_replace(unsigned long ip)
{ {
__raw_writel(ip + MCOUNT_INSN_SIZE, ftrace_nop);
return ftrace_nop; return ftrace_nop;
} }
static int is_sh_nop(unsigned char *ip) static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
{
return strncmp(ip, ftrace_nop, sizeof(ftrace_nop));
}
unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
{ {
/* Place the address in the memory table. */ /* Place the address in the memory table. */
if (addr == CALLER_ADDR) __raw_writel(addr, ftrace_replaced_code);
__raw_writel(addr + MCOUNT_INSN_OFFSET, ftrace_replaced_code);
else
__raw_writel(addr, ftrace_replaced_code);
/* /*
* No locking needed, this must be called via kstop_machine * No locking needed, this must be called via kstop_machine
@@ -51,7 +58,7 @@ unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
return ftrace_replaced_code; return ftrace_replaced_code;
} }
int ftrace_modify_code(unsigned long ip, unsigned char *old_code, static int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
unsigned char *new_code) unsigned char *new_code)
{ {
unsigned char replaced[MCOUNT_INSN_SIZE]; unsigned char replaced[MCOUNT_INSN_SIZE];
@@ -66,13 +73,6 @@ int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
* kstop_machine, or before SMP starts. * kstop_machine, or before SMP starts.
*/ */
/*
* If we're trying to nop out a call to a function, we instead
* place a call to the address after the memory table.
*/
if (is_sh_nop(new_code) == 0)
__raw_writel(ip + MCOUNT_INSN_SIZE, (unsigned long)new_code);
/* read the text we want to modify */ /* read the text we want to modify */
if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE)) if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
return -EFAULT; return -EFAULT;
@@ -92,13 +92,13 @@ int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
int ftrace_update_ftrace_func(ftrace_func_t func) int ftrace_update_ftrace_func(ftrace_func_t func)
{ {
unsigned long ip = (unsigned long)(&ftrace_call); unsigned long ip = (unsigned long)(&ftrace_call) + MCOUNT_INSN_OFFSET;
unsigned char old[MCOUNT_INSN_SIZE], *new; unsigned char old[MCOUNT_INSN_SIZE], *new;
memcpy(old, (unsigned char *)(ip + MCOUNT_INSN_OFFSET), MCOUNT_INSN_SIZE); memcpy(old, (unsigned char *)ip, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(ip, (unsigned long)func); new = ftrace_call_replace(ip, (unsigned long)func);
return ftrace_modify_code(ip + MCOUNT_INSN_OFFSET, old, new); return ftrace_modify_code(ip, old, new);
} }
int ftrace_make_nop(struct module *mod, int ftrace_make_nop(struct module *mod,
@@ -108,7 +108,7 @@ int ftrace_make_nop(struct module *mod,
unsigned long ip = rec->ip; unsigned long ip = rec->ip;
old = ftrace_call_replace(ip, addr); old = ftrace_call_replace(ip, addr);
new = ftrace_nop_replace(); new = ftrace_nop_replace(ip);
return ftrace_modify_code(rec->ip, old, new); return ftrace_modify_code(rec->ip, old, new);
} }
@@ -118,7 +118,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
unsigned char *new, *old; unsigned char *new, *old;
unsigned long ip = rec->ip; unsigned long ip = rec->ip;
old = ftrace_nop_replace(); old = ftrace_nop_replace(ip);
new = ftrace_call_replace(ip, addr); new = ftrace_call_replace(ip, addr);
return ftrace_modify_code(rec->ip, old, new); return ftrace_modify_code(rec->ip, old, new);