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Subject[PATCH] include/linux/compiler*.h: add version detection to asm_volatile_goto
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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.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
include/linux/compiler-gcc.h | 7 ++++++-
include/linux/compiler_types.h | 4 ++++
2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 763bbad1e258..149f411b4366 100644
--- a/include/linux/compiler-gcc.h
+++ b/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
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 3525c179698c..61449dbf30d8 100644
--- a/include/linux/compiler_types.h
+++ b/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))

--
2.19.0.rc2.392.g5ba43deb5a-goog
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