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Commit c36ef4b1 authored by Will Deacon's avatar Will Deacon Committed by Russell King
Browse files

ARM: 7171/1: unwind: add unwind directives to bitops assembly macros 



The bitops functions (e.g. _test_and_set_bit) on ARM do not have unwind
annotations and therefore the kernel cannot backtrace out of them on a
fatal error (for example, NULL pointer dereference).

This patch annotates the bitops assembly macros with UNWIND annotations
so that we can produce a meaningful backtrace on error. Callers of the
macros are modified to pass their function name as a macro parameter,
enforcing that the macros are used as standalone function implementations.

Acked-by: default avatarDave Martin <dave.martin@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent c89cefed

arch/arm/lib/bitops.h

+22 −4
Original line number Diff line number Diff line 
#include <asm/unwind.h>



#if __LINUX_ARM_ARCH__ >= 6

	.macro	bitop, instr

	.macro	bitop, name, instr

ENTRY(	\name		)

UNWIND(	.fnstart	)

	ands	ip, r1, #3

	strneb	r1, [ip]		@ assert word-aligned

	mov	r2, #1
@@ -13,9 +17,13 @@ 
	cmp	r0, #0

	bne	1b

	bx	lr

UNWIND(	.fnend		)

ENDPROC(\name		)

	.endm



	.macro	testop, instr, store

	.macro	testop, name, instr, store

ENTRY(	\name		)

UNWIND(	.fnstart	)

	ands	ip, r1, #3

	strneb	r1, [ip]		@ assert word-aligned

	mov	r2, #1
@@ -34,9 +42,13 @@ 
	cmp	r0, #0

	movne	r0, #1

2:	bx	lr

UNWIND(	.fnend		)

ENDPROC(\name		)

	.endm

#else

	.macro	bitop, instr

	.macro	bitop, name, instr

ENTRY(	\name		)

UNWIND(	.fnstart	)

	ands	ip, r1, #3

	strneb	r1, [ip]		@ assert word-aligned

	and	r2, r0, #31
@@ -49,6 +61,8 @@ 
	str	r2, [r1, r0, lsl #2]

	restore_irqs ip

	mov	pc, lr

UNWIND(	.fnend		)

ENDPROC(\name		)

	.endm



/**
@@ -59,7 +73,9 @@ 
 * Note: we can trivially conditionalise the store instruction

 * to avoid dirtying the data cache.

 */

	.macro	testop, instr, store

	.macro	testop, name, instr, store

ENTRY(	\name		)

UNWIND(	.fnstart	)

	ands	ip, r1, #3

	strneb	r1, [ip]		@ assert word-aligned

	and	r3, r0, #31
@@ -73,5 +89,7 @@ 
	moveq	r0, #0

	restore_irqs ip

	mov	pc, lr

UNWIND(	.fnend		)

ENDPROC(\name		)

	.endm

#endif

arch/arm/lib/changebit.S

+1 −3
Original line number Diff line number Diff line
@@ -12,6 +12,4 @@ 
#include "bitops.h"

                .text



ENTRY(_change_bit)

	bitop	eor

ENDPROC(_change_bit)
 
bitop	_change_bit, eor

arch/arm/lib/clearbit.S

+1 −3
Original line number Diff line number Diff line
@@ -12,6 +12,4 @@ 
#include "bitops.h"

                .text



ENTRY(_clear_bit)

	bitop	bic

ENDPROC(_clear_bit)
 
bitop	_clear_bit, bic

arch/arm/lib/setbit.S

+1 −3
Original line number Diff line number Diff line
@@ -12,6 +12,4 @@ 
#include "bitops.h"

		.text



ENTRY(_set_bit)

	bitop	orr

ENDPROC(_set_bit)
 
bitop	_set_bit, orr

arch/arm/lib/testchangebit.S

+1 −3
Original line number Diff line number Diff line
@@ -12,6 +12,4 @@ 
#include "bitops.h"

                .text



ENTRY(_test_and_change_bit)

	testop	eor, str

ENDPROC(_test_and_change_bit)
 
testop	_test_and_change_bit, eor, str