alistair23-linux/arch/arm64/kernel/return_address.c
Ard Biesheuvel 31e43ad3b7 arm64: unwind: remove sp from struct stackframe
The unwind code sets the sp member of struct stackframe to
'frame pointer + 0x10' unconditionally, without regard for whether
doing so produces a legal value. So let's simply remove it now that
we have stopped using it anyway.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
2017-08-09 14:10:29 +01:00

58 lines
1.2 KiB
C

/*
* 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/stack_pointer.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;
data.level = level + 2;
data.addr = NULL;
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.pc = (unsigned long)return_address; /* dummy */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame.graph = current->curr_ret_stack;
#endif
walk_stackframe(current, &frame, save_return_addr, &data);
if (!data.level)
return data.addr;
else
return NULL;
}
EXPORT_SYMBOL_GPL(return_address);