The patch titled
Subject: include/linux/compiler*.h: add version detection to asm_volatile_goto
has been added to the -mm tree. Its filename is
include-linux-compilerh-add-version-detection-to-asm_volatile_goto.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/include-linux-compilerh-add-version-detection-to-asm_volatile_goto.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/include-linux-compilerh-add-version-detection-to-asm_volatile_goto.patch
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------------------------------------------------------
From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Subject: include/linux/compiler*.h: add version detection to asm_volatile_goto
The comment above asm_volatile_goto mentions working around a GCC bug, and
links to a bug report that claims this has been fixed in newer versions of
GCC. Testing shows that this was resolved in GCC 4.8.2.
asm_volatile_goto should also be defined for other compilers that support
asm goto.
Link: http://lkml.kernel.org/r/20180907222109.163802-1-ndesaulniers@xxxxxxxxxx
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/compiler-gcc.h | 7 ++++++-
include/linux/compiler_types.h | 4 ++++
2 files changed, 10 insertions(+), 1 deletion(-)
--- a/include/linux/compiler-gcc.h~include-linux-compilerh-add-version-detection-to-asm_volatile_goto
+++ a/include/linux/compiler-gcc.h
@@ -171,7 +171,7 @@
#endif
/*
- * GCC 'asm goto' miscompiles certain code sequences:
+ * GCC < 4.8.2 'asm goto' miscompiles certain code sequences:
*
* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
*
@@ -179,7 +179,12 @@
*
* (asm goto is automatically volatile - the naming reflects this.)
*/
+#if GCC_VERSION < 40802
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
+#else
+#define asm_volatile_goto(x...) asm goto(x)
+#endif
+
/*
* sparse (__CHECKER__) pretends to be gcc, but can't do constant
--- a/include/linux/compiler_types.h~include-linux-compilerh-add-version-detection-to-asm_volatile_goto
+++ a/include/linux/compiler_types.h
@@ -151,6 +151,10 @@ struct ftrace_likely_data {
#define __assume_aligned(a, ...)
#endif
+#ifndef asm_volatile_goto
+#define asm_volatile_goto(x...) asm goto(x)
+#endif
+
/* Are two types/vars the same type (ignoring qualifiers)? */
#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
_
Patches currently in -mm which might be from ndesaulniers@xxxxxxxxxx are
include-linux-compilerh-add-version-detection-to-asm_volatile_goto.patch
