Commit 20cb6abf authored by Lin Yongting's avatar Lin Yongting Committed by Russell King
Browse files

ARM: 8223/1: Add unwinding support for __memzero function 



The __memzero function never had unwinding annotations added.
Currently, when accessing invalid pointer by __memzero occurs the
backtrace shown will stop at __memzero 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 __memzero
2. kprobe trapped at any instruction within __memzero
3. interrupted at any instruction within __memzero

Signed-off-by: default avatarLin Yongting <linyongting@gmail.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 296630c9

arch/arm/lib/memzero.S

+12 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
 */

#include <linux/linkage.h>

#include <asm/assembler.h>

#include <asm/unwind.h>



	.text

	.align	5
@@ -18,6 +19,7 @@ 
 * mis-aligned by, and r1 is the number of bytes.  If r1 < 4, then we

 * don't bother; we use byte stores instead.

 */

UNWIND(	.fnstart			)

1:	subs	r1, r1, #4		@ 1 do we have enough

	blt	5f			@ 1 bytes to align with?

	cmp	r3, #2			@ 1
@@ -47,6 +49,9 @@ ENTRY(__memzero) 
 * use the LR

 */

	str	lr, [sp, #-4]!		@ 1

UNWIND(	.fnend				)

UNWIND(	.fnstart			)

UNWIND(	.save 	{lr}			)

	mov	ip, r2			@ 1

	mov	lr, r2			@ 1
@@ -66,6 +71,7 @@ ENTRY(__memzero) 
	tst	r1, #16			@ 1 16 bytes or more?

	stmneia	r0!, {r2, r3, ip, lr}	@ 4

	ldr	lr, [sp], #4		@ 1

UNWIND(	.fnend				)



#else
@@ -75,6 +81,9 @@ ENTRY(__memzero) 
 */



	stmfd	sp!, {r4-r7, lr}

UNWIND(	.fnend		       )

UNWIND(	.fnstart	       )

UNWIND(	.save 	{r4-r7, lr}    )

	mov	r4, r2

	mov	r5, r2

	mov	r6, r2
@@ -105,9 +114,11 @@ ENTRY(__memzero) 
	tst	r1, #16

	stmneia	r0!, {r4-r7}

	ldmfd	sp!, {r4-r7, lr}

UNWIND(	.fnend		       )



#endif



UNWIND(	.fnstart			)

4:	tst	r1, #8			@ 1 8 bytes or more?

	stmneia	r0!, {r2, r3}		@ 2

	tst	r1, #4			@ 1 4 bytes or more?
@@ -122,4 +133,5 @@ ENTRY(__memzero) 
	tst	r1, #1			@ 1 a byte left over

	strneb	r2, [r0], #1		@ 1

	ret	lr			@ 1

UNWIND(	.fnend				)

ENDPROC(__memzero)