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ARM: 8225/1: Add unwinding support for memory copy functions

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The memory copy functions(memcpy, __copy_from_user, __copy_to_user)
never had unwinding annotations added. Currently, when accessing
invalid pointer by these functions occurs the backtrace shown will
stop at these functions or some completely unrelated function.
Add unwinding annotations in hopes of getting a more useful backtrace
in following cases:
1. die on accessing invalid pointer by these functions
2. kprobe trapped at any instruction within these functions
3. interrupted at any instruction within these functions

Signed-off-by: Lin Yongting <linyongting@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Lin Yongting
2014-11-26 14:38:33 +01:00
committed by Russell King
parent 207a6cb069
commit 279f487e0b
4 changed files with 45 additions and 0 deletions
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5
arch/arm/lib/copy_to_user.S
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@@ -12,6 +12,7 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unwind.h>
/*
* Prototype:
@@ -80,6 +81,10 @@
stmdb sp!, {r0, r2, r3, \reg1, \reg2}
.endm
.macro usave reg1 reg2
UNWIND( .save {r0, r2, r3, \reg1, \reg2} )
.endm
.macro exit reg1 reg2
add sp, sp, #8
ldmfd sp!, {r0, \reg1, \reg2}