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arm64: ftrace: Add CALLER_ADDRx macros 

CALLER_ADDRx returns caller's address at specified level in call stacks.
They are used for several tracers like irqsoff and preemptoff.
Strange to say, however, they are refered even without FTRACE.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
AKASHI Takahiro 2014-04-30 10:54:35 +01:00 committed by Will Deacon
parent bd7d38dbdf
commit 3711784ece
3 changed files with 61 additions and 2 deletions
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5
arch/arm64/include/asm/ftrace.h
View File

@ -18,6 +18,7 @@
#ifndef __ASSEMBLY__
extern void _mcount(unsigned long);
extern void *return_address(unsigned int);
struct dyn_arch_ftrace {
/* No extra data needed for arm64 */
@ -33,6 +34,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
*/
return addr;
}
#endif /* __ASSEMBLY__ */
#define ftrace_return_address(n) return_address(n)
#endif /* ifndef __ASSEMBLY__ */
#endif /* __ASM_FTRACE_H */

3
arch/arm64/kernel/Makefile
View File

@ -7,12 +7,13 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_insn.o = -pg
CFLAGS_REMOVE_return_address.o = -pg
# Object file lists.
arm64-obj-y := cputable.o debug-monitors.o entry.o irq.o fpsimd.o \
entry-fpsimd.o process.o ptrace.o setup.o signal.o \
sys.o stacktrace.o time.o traps.o io.o vdso.o \
hyp-stub.o psci.o cpu_ops.o insn.o
hyp-stub.o psci.o cpu_ops.o insn.o return_address.o
arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o

55
arch/arm64/kernel/return_address.c Normal file
View File

@ -0,0 +1,55 @@
/*
* arch/arm64/kernel/return_address.c
*
* Copyright (C) 2013 Linaro Limited
* Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/export.h>
#include <linux/ftrace.h>
#include <asm/stacktrace.h>
struct return_address_data {
unsigned int level;
void *addr;
};
static int save_return_addr(struct stackframe *frame, void *d)
{
struct return_address_data *data = d;
if (!data->level) {
data->addr = (void *)frame->pc;
return 1;
} else {
--data->level;
return 0;
}
}
void *return_address(unsigned int level)
{
struct return_address_data data;
struct stackframe frame;
register unsigned long current_sp asm ("sp");
data.level = level + 2;
data.addr = NULL;
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_sp;
frame.pc = (unsigned long)return_address; /* dummy */
walk_stackframe(&frame, save_return_addr, &data);
if (!data.level)
return data.addr;
else
return NULL;
}
EXPORT_SYMBOL_GPL(return_address);