Merge branch 'sh/ftrace' of git://github.com/mfleming/linux-2.6 (cf64c800) · Commits · e / devices / android_kernel_teracube_2e

arch/sh/kernel/ftrace.c

+30 −30

Original line number	Original line	Diff line number	Diff line
	/*		/*
	* 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.
	@@ -19,29 +19,36 @@
	#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 + MCOUNT_INSN_OFFSET, ftrace_replaced_code);
	else
	__raw_writel(addr, ftrace_replaced_code);		__raw_writel(addr, ftrace_replaced_code);

	/*		/*
	@@ -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);