The coming x86 refcount protection needs to be able to add trailing
instructions to the GEN_*_RMWcc() operations. This extracts the
difference between the goto/non-goto cases so the helper macros
can be defined outside the #ifdef cases. Additionally adds argument
naming to the resulting asm for referencing from suffixed
instructions, and adds clobbers for "cc", and "cx" to let suffixes
use _ASM_CX, and retain any set flags.
Signed-off-by: Kees Cook <keesc...@chromium.org>
---
arch/x86/include/asm/rmwcc.h | 37 ++++++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index 661dd305694a..045f99211a99 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -1,45 +1,56 @@
#ifndef _ASM_X86_RMWcc
#define _ASM_X86_RMWcc
+#define __CLOBBERS_MEM "memory"
+#define __CLOBBERS_MEM_CC_CX "memory", "cc", "cx"
+
#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)
/* Use asm goto */
-#define __GEN_RMWcc(fullop, var, cc, ...) \
+#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
do { \
asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \
- : : "m" (var), ## __VA_ARGS__ \
- : "memory" : cc_label); \
+ : : [counter] "m" (var), ## __VA_ARGS__ \
+ : clobbers : cc_label); \
return 0; \
cc_label: \
return 1; \
} while (0)
-#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
- __GEN_RMWcc(op " " arg0, var, cc)
+#define __BINARY_RMWcc_ARG " %1, "
-#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
- __GEN_RMWcc(op " %1, " arg0, var, cc, vcon (val))
#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
/* Use flags output or a set instruction */
-#define __GEN_RMWcc(fullop, var, cc, ...) \
+#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
do { \
bool c; \
asm volatile (fullop ";" CC_SET(cc) \
- : "+m" (var), CC_OUT(cc) (c) \
- : __VA_ARGS__ : "memory"); \
+ : [counter] "+m" (var), CC_OUT(cc) (c) \
+ : __VA_ARGS__ : clobbers); \
return c; \
} while (0)
+#define __BINARY_RMWcc_ARG " %2, "
+
+#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
+
#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
- __GEN_RMWcc(op " " arg0, var, cc)
+ __GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM)
+
+#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc) \
+ __GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc, \
+ __CLOBBERS_MEM_CC_CX)
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
- __GEN_RMWcc(op " %2, " arg0, var, cc, vcon (val))
+ __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc, \
+ __CLOBBERS_MEM, vcon (val))
-#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
+#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc)
\
+ __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0 "\n\t" suffix, var, cc, \
+ __CLOBBERS_MEM_CC_CX, vcon (val))
#endif /* _ASM_X86_RMWcc */
--
2.7.4
