ARM: 7946/1: asm: __und_usr_thumb need byteswap instructions in BE case

__und_usr_thumb function deals with thumb2 opcodes. In case of BE
image, it needs to byteswap half word thumb2 encoded instructions
before further processing them.

Without this fix BE image user-land thread executing first VFP
instruction encoded in thumb2 fails with SIGILL, because kernel
does not recognize instruction and does not enable VFP.

Reported-by: Corey Melton <comelton@cisco.com>
Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index b3fb8c9e1ff2..1879e8dd2acc 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -451,9 +451,11 @@ __und_usr_thumb:
         .arch   armv6t2
 #endif
 2:      ldrht   r5, [r4]
+ARM_BE8(rev16   r5, r5)                         @ little endian instruction
         cmp     r5, #0xe800                     @ 32bit instruction if xx != 0
         blo     __und_usr_fault_16              @ 16bit undefined instruction
 3:      ldrht   r0, [r2]
+ARM_BE8(rev16   r0, r0)                         @ little endian instruction
         add     r2, r2, #2                      @ r2 is PC + 2, make it PC + 4
         str     r2, [sp, #S_PC]                 @ it's a 2x16bit instr, update
         orr     r0, r0, r5, lsl #16