ARM: 8475/1: SWP emulation: Restore original *data when failed

__user_swpX_asm maybe failed in first STREX operation, emulate_swpX
will try again, but the *data has been changed in first time. which
causes the result is wrong.
This patch is to fix this issue. When STREX succeed, change the *data.
if it fail, *data is not changed.

Signed-off-by: Shengjiu Wang <shengjiu.wang@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c
index 5b26e7e..c3fe769 100644 (file)
--- a/arch/arm/kernel/swp_emulate.c
+++ b/arch/arm/kernel/swp_emulate.c
@@ -36,10 +36,10 @@
  */
 #define __user_swpX_asm(data, addr, res, temp, B)              \
        __asm__ __volatile__(                                   \
-       "       mov             %2, %1\n"                       \
-       "0:     ldrex"B"        %1, [%3]\n"                     \
-       "1:     strex"B"        %0, %2, [%3]\n"                 \
+       "0:     ldrex"B"        %2, [%3]\n"                     \
+       "1:     strex"B"        %0, %1, [%3]\n"                 \
        "       cmp             %0, #0\n"                       \
+       "       moveq           %1, %2\n"                       \
        "       movne           %0, %4\n"                       \
        "2:\n"                                                  \
        "       .section         .text.fixup,\"ax\"\n"          \