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Commit 395a59d0 authored by Abhishek Sagar's avatar Abhishek Sagar Committed by Ingo Molnar
Browse files

ftrace: store mcount address in rec->ip 



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: default avatarAbhishek Sagar <sagar.abhishek@gmail.com>
Cc: davem@davemloft.net
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f34bfb1b

arch/arm/kernel/armksyms.c

+5 −5
Original line number Diff line number Diff line
@@ -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

arch/arm/kernel/entry-common.S

+4 −0
Original line number Diff line number Diff line
@@ -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}

arch/arm/kernel/ftrace.c

+7 −9
Original line number Diff line number Diff line
@@ -12,9 +12,10 @@ 
 */



#include <linux/ftrace.h>



#include <asm/cacheflush.h>

#include <asm/ftrace.h>



#define INSN_SIZE      4

#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;

arch/powerpc/kernel/entry_32.S

+4 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <asm/ppc_asm.h>

#include <asm/asm-offsets.h>

#include <asm/unistd.h>

#include <asm/ftrace.h>



#undef SHOW_SYSCALLS

#undef SHOW_SYSCALLS_TASK
@@ -1053,6 +1054,7 @@ _GLOBAL(_mcount) 
	stw	r10,40(r1)

	stw	r3, 44(r1)

	stw	r5, 8(r1)

	subi	r3, r3, MCOUNT_INSN_SIZE

	.globl mcount_call

mcount_call:

	bl	ftrace_stub
@@ -1090,6 +1092,7 @@ _GLOBAL(ftrace_caller) 
	stw	r10,40(r1)

	stw	r3, 44(r1)

	stw	r5, 8(r1)

	subi	r3, r3, MCOUNT_INSN_SIZE

.globl ftrace_call

ftrace_call:

	bl	ftrace_stub
@@ -1128,6 +1131,7 @@ _GLOBAL(_mcount) 
	stw	r3, 44(r1)

	stw	r5, 8(r1)



	subi	r3, r3, MCOUNT_INSN_SIZE

	LOAD_REG_ADDR(r5, ftrace_trace_function)

	lwz	r5,0(r5)

arch/powerpc/kernel/entry_64.S

+4 −1
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <asm/bug.h>

#include <asm/ptrace.h>

#include <asm/irqflags.h>

#include <asm/ftrace.h>



/*

 * System calls.
@@ -879,6 +880,7 @@ _GLOBAL(_mcount) 
	mflr	r3

	stdu	r1, -112(r1)

	std	r3, 128(r1)

	subi	r3, r3, MCOUNT_INSN_SIZE

	.globl mcount_call

mcount_call:

	bl	ftrace_stub
@@ -895,6 +897,7 @@ _GLOBAL(ftrace_caller) 
	stdu	r1, -112(r1)

	std	r3, 128(r1)

	ld	r4, 16(r11)

	subi	r3, r3, MCOUNT_INSN_SIZE

.globl ftrace_call

ftrace_call:

	bl	ftrace_stub
@@ -916,7 +919,7 @@ _GLOBAL(_mcount) 
	std	r3, 128(r1)

	ld	r4, 16(r11)





	subi	r3, r3, MCOUNT_INSN_SIZE

	LOAD_REG_ADDR(r5,ftrace_trace_function)

	ld	r5,0(r5)

	ld	r5,0(r5)