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: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2013-07-04 11:32:04 +01:00
parent f928d4f2a8
commit 5b43e7a383

View File

@ -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