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Commit 207a6cb0 authored by Lin Yongting's avatar Lin Yongting Committed by Russell King
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ARM: 8224/1: Add unwinding support for memmove function 



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

Signed-off-by: default avatarLin Yongting <linyongting@gmail.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 20cb6abf

arch/arm/lib/memmove.S

+28 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 


#include <linux/linkage.h>

#include <asm/assembler.h>

#include <asm/unwind.h>



		.text
@@ -27,12 +28,17 @@ 
 */



ENTRY(memmove)

	UNWIND(	.fnstart			)



		subs	ip, r0, r1

		cmphi	r2, ip

		bls	memcpy



		stmfd	sp!, {r0, r4, lr}

	UNWIND(	.fnend				)



	UNWIND(	.fnstart			)

	UNWIND(	.save	{r0, r4, lr}		) @ in first stmfd block

		add	r1, r1, r2

		add	r0, r0, r2

		subs	r2, r2, #4
@@ -45,6 +51,11 @@ ENTRY(memmove) 


1:		subs	r2, r2, #(28)

		stmfd	sp!, {r5 - r8}

	UNWIND(	.fnend				)



	UNWIND(	.fnstart			)

	UNWIND(	.save	{r0, r4, lr}		)

	UNWIND(	.save	{r5 - r8}		) @ in second stmfd block

		blt	5f



	CALGN(	ands	ip, r0, #31		)
@@ -97,6 +108,10 @@ ENTRY(memmove) 
	CALGN(	bcs	2b			)



7:		ldmfd	sp!, {r5 - r8}

	UNWIND(	.fnend				) @ end of second stmfd block



	UNWIND(	.fnstart			)

	UNWIND(	.save	{r0, r4, lr}		) @ still in first stmfd block



8:		movs	r2, r2, lsl #31

		ldrneb	r3, [r1, #-1]!
@@ -124,10 +139,13 @@ ENTRY(memmove) 
		ldr	r3, [r1, #0]

		beq	17f

		blt	18f

	UNWIND(	.fnend				)





		.macro	backward_copy_shift push pull



	UNWIND(	.fnstart			)

	UNWIND(	.save	{r0, r4, lr}		) @ still in first stmfd block

		subs	r2, r2, #28

		blt	14f
@@ -137,6 +155,11 @@ ENTRY(memmove) 
	CALGN(	bcc	15f			)



11:		stmfd	sp!, {r5 - r9}

	UNWIND(	.fnend				)



	UNWIND(	.fnstart			)

	UNWIND(	.save	{r0, r4, lr}		)

	UNWIND(	.save	{r5 - r9}		) @ in new second stmfd block



	PLD(	pld	[r1, #-4]		)

	PLD(	subs	r2, r2, #96		)
@@ -171,6 +194,10 @@ ENTRY(memmove) 
	PLD(	bge	13b			)



		ldmfd	sp!, {r5 - r9}

	UNWIND(	.fnend				) @ end of the second stmfd block



	UNWIND(	.fnstart			)

	UNWIND(	.save {r0, r4, lr}		) @ still in first stmfd block



14:		ands	ip, r2, #28

		beq	16f
@@ -186,6 +213,7 @@ ENTRY(memmove) 


16:		add	r1, r1, #(\pull / 8)

		b	8b

	UNWIND(	.fnend				)



		.endm