3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Russell King <rmk+ker...@arm.linux.org.uk>
commit 5b43e7a383d69381ffe53423e46dd0fafae07da3 upstream.
Poison the memory between each kuser helper. This ensures that any
branch between the kuser helpers will be appropriately trapped.
Acked-by: Nicolas Pitre <n...@linaro.org>
Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/arm/kernel/entry-armv.S | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -741,6 +741,17 @@ 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:
@@ -831,18 +842,13 @@ 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
@@ -915,13 +921,14 @@ 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
--
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