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ARM: 7676/1: fix a wrong value returned from CALLER_ADDRn

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This makes return_address() return a correct value for CALLER_ADDRn.
To have a correct value from CALLER_ADDRn, we need to fix three points.

* The unwind_frame() does not update frame->lr but frame->pc for backtrace.
So frame->pc is meaningful for backtrace.

* data.level should be adjusted by adding 2 additional iteration levels.
With the current +1 level adjustment, the result of CALLER_ADDR1 will
be the same return address with CALLER_ADDR0.

* The initialization of data.addr to NULL is needed.
When unwind_fame() fails right after data.level reaches zero,
the routine returns data.addr which has uninitialized garbage value.

Signed-off-by: Sahara <keun-o.park@windriver.com>
Reviewed-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Keun-O Park 2013-03-18 07:32:53 +01:00 committed by Russell King
parent 3b4af9bc24
commit 01223f3650
1 changed files with 3 additions and 2 deletions
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5
arch/arm/kernel/return_address.c
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@ -26,7 +26,7 @@ static int save_return_addr(struct stackframe *frame, void *d)
struct return_address_data *data = d;
if (!data->level) {
data->addr = (void *)frame->lr;
data->addr = (void *)frame->pc;
return 1;
} else {
@ -41,7 +41,8 @@ void *return_address(unsigned int level)
struct stackframe frame;
register unsigned long current_sp asm ("sp");
data.level = level + 1;
data.level = level + 2;
data.addr = NULL;
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_sp;