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Commit 5b43e7a3 authored by Russell King's avatar Russell King
Browse files

ARM: poison memory between kuser helpers 



Poison the memory between each kuser helper.  This ensures that any
branch between the kuser helpers will be appropriately trapped.

Cc: <stable@vger.kernel.org>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent f928d4f2

arch/arm/kernel/entry-armv.S

+16 −9
Original line number Diff line number Diff line
@@ -742,6 +742,17 @@ ENDPROC(__switch_to) 
#endif

	.endm



	.macro	kuser_pad, sym, size

	.if	(. - \sym) & 3

	.rept	4 - (. - \sym) & 3

	.byte	0

	.endr

	.endif

	.rept	(\size - (. - \sym)) / 4

	.word	0xe7fddef1

	.endr

	.endm



	.align	5

	.globl	__kuser_helper_start

__kuser_helper_start:
@@ -832,18 +843,13 @@ kuser_cmpxchg64_fixup: 
#error "incoherent kernel configuration"

#endif



	/* pad to next slot */

	.rept	(16 - (. - __kuser_cmpxchg64)/4)

	.word	0

	.endr



	.align	5

	kuser_pad __kuser_cmpxchg64, 64



__kuser_memory_barrier:				@ 0xffff0fa0

	smp_dmb	arm

	usr_ret	lr



	.align	5

	kuser_pad __kuser_memory_barrier, 32



__kuser_cmpxchg:				@ 0xffff0fc0
@@ -916,13 +922,14 @@ kuser_cmpxchg32_fixup: 


#endif



	.align	5

	kuser_pad __kuser_cmpxchg, 32



__kuser_get_tls:				@ 0xffff0fe0

	ldr	r0, [pc, #(16 - 8)]	@ read TLS, set in kuser_get_tls_init

	usr_ret	lr

	mrc	p15, 0, r0, c13, c0, 3	@ 0xffff0fe8 hardware TLS code

	.rep	4

	kuser_pad __kuser_get_tls, 16

	.rep	3

	.word	0			@ 0xffff0ff0 software TLS value, then

	.endr				@ pad up to __kuser_helper_version