From: "H. Peter Anvin" <h...@zytor.com>
Change the GEN_*_RMWcc() macros to use the CC_SET()/CC_OUT() macros
defined in <asm/asm.h>, and disable the use of asm goto if
__GCC_ASM_FLAG_OUTPUTS__ is enabled. This allows gcc to receive the
flags output directly in gcc 6+.
Signed-off-by: H. Peter Anvin <h...@zytor.com>
Reviewed-by: Andy Lutomirski <l...@kernel.org>
Reviewed-by: Borislav Petkov <b...@suse.de>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/x86/include/asm/rmwcc.h | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index e3264c4..661dd30 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -1,7 +1,9 @@
#ifndef _ASM_X86_RMWcc
#define _ASM_X86_RMWcc
-#ifdef CC_HAVE_ASM_GOTO
+#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)
+
+/* Use asm goto */
#define __GEN_RMWcc(fullop, var, cc, ...) \
do { \
@@ -19,13 +21,15 @@ cc_label:
\
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op " %1, " arg0, var, cc, vcon (val))
-#else /* !CC_HAVE_ASM_GOTO */
+#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
+
+/* Use flags output or a set instruction */
#define __GEN_RMWcc(fullop, var, cc, ...) \
do { \
bool c; \
- asm volatile (fullop "; set" #cc " %1" \
- : "+m" (var), "=qm" (c) \
+ asm volatile (fullop ";" CC_SET(cc) \
+ : "+m" (var), CC_OUT(cc) (c) \
: __VA_ARGS__ : "memory"); \
return c; \
} while (0)
@@ -36,6 +40,6 @@ do {
\
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op " %2, " arg0, var, cc, vcon (val))
-#endif /* CC_HAVE_ASM_GOTO */
+#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
#endif /* _ASM_X86_RMWcc */
--
2.7.3.0.11.gd79db92
