ARM: 8475/1: SWP emulation: Restore original *data when failed
authorShengjiu Wang <shengjiu.wang@freescale.com>
Tue, 8 Dec 2015 12:37:19 +0000 (13:37 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Tue, 15 Dec 2015 11:51:42 +0000 (11:51 +0000)
__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>
arch/arm/kernel/swp_emulate.c

index 5b26e7efa9ea415967b63ede27ab1edf2bc8e888..c3fe769d75584c7248015b855bca904589f3e29f 100644 (file)
  */
 #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"          \