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Commit a771fe6e authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
Browse files

ARM: 5757/1: Thumb-2: Correct "mov.w pc, lr" instruction which is unpredictable 



The 32-bit wide variant of "mov pc, reg" in Thumb-2 is unpredictable
causing improper handling of the undefined instructions not caught by
the kernel. This patch adds a movw_pc macro for such situations
(currently only used in call_fpe).

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 80f50691

arch/arm/kernel/entry-armv.S

+14 −14
Original line number Diff line number Diff line
@@ -608,33 +608,33 @@ call_fpe: 
 THUMB(	add	pc, r8			)

	nop



	W(mov)	pc, lr				@ CP#0

	movw_pc	lr				@ CP#0

	W(b)	do_fpe				@ CP#1 (FPE)

	W(b)	do_fpe				@ CP#2 (FPE)

	W(mov)	pc, lr				@ CP#3

	movw_pc	lr				@ CP#3

#ifdef CONFIG_CRUNCH

	b	crunch_task_enable		@ CP#4 (MaverickCrunch)

	b	crunch_task_enable		@ CP#5 (MaverickCrunch)

	b	crunch_task_enable		@ CP#6 (MaverickCrunch)

#else

	W(mov)	pc, lr				@ CP#4

	W(mov)	pc, lr				@ CP#5

	W(mov)	pc, lr				@ CP#6

	movw_pc	lr				@ CP#4

	movw_pc	lr				@ CP#5

	movw_pc	lr				@ CP#6

#endif

	W(mov)	pc, lr				@ CP#7

	W(mov)	pc, lr				@ CP#8

	W(mov)	pc, lr				@ CP#9

	movw_pc	lr				@ CP#7

	movw_pc	lr				@ CP#8

	movw_pc	lr				@ CP#9

#ifdef CONFIG_VFP

	W(b)	do_vfp				@ CP#10 (VFP)

	W(b)	do_vfp				@ CP#11 (VFP)

#else

	W(mov)	pc, lr				@ CP#10 (VFP)

	W(mov)	pc, lr				@ CP#11 (VFP)

	movw_pc	lr				@ CP#10 (VFP)

	movw_pc	lr				@ CP#11 (VFP)

#endif

	W(mov)	pc, lr				@ CP#12

	W(mov)	pc, lr				@ CP#13

	W(mov)	pc, lr				@ CP#14 (Debug)

	W(mov)	pc, lr				@ CP#15 (Control)

	movw_pc	lr				@ CP#12

	movw_pc	lr				@ CP#13

	movw_pc	lr				@ CP#14 (Debug)

	movw_pc	lr				@ CP#15 (Control)



#ifdef CONFIG_NEON

	.align	6

arch/arm/kernel/entry-header.S

+15 −0
Original line number Diff line number Diff line
@@ -110,6 +110,13 @@ 
	mov	\rd, sp, lsr #13

	mov	\rd, \rd, lsl #13

	.endm



	@

	@ 32-bit wide "mov pc, reg"

	@

	.macro	movw_pc, reg

	mov	pc, \reg

	.endm

#else	/* CONFIG_THUMB2_KERNEL */

	.macro	svc_exit, rpsr

	clrex					@ clear the exclusive monitor
@@ -146,6 +153,14 @@ 
	lsr	\rd, \rd, #13

	mov	\rd, \rd, lsl #13

	.endm



	@

	@ 32-bit wide "mov pc, reg"

	@

	.macro	movw_pc, reg

	mov	pc, \reg

	nop

	.endm

#endif	/* !CONFIG_THUMB2_KERNEL */



/*