path: root/include
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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-19 07:52:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-19 07:52:48 -0800
commit7f2de8171ddf28fdb2ca7f9a683ee1207849f718 (patch)
treed89da981ac762de3fd32e1c08ddc8041f3c37519 /include
parent59771079c18c44e39106f0f30054025acafadb41 (diff)
parentcf66bb93e0f75e0a4ba1ec070692618fa028e994 (diff)
Merge tag 'byteswap-for-linus-20121219' of git://git.infradead.org/users/dwmw2/byteswap
Pull preparatory gcc intrisics bswap patch from David Woodhouse: "This single patch is effectively a no-op for now. It enables architectures to opt in to using GCC's __builtin_bswapXX() intrinsics for byteswapping, and if we merge this now then the architecture maintainers can enable it for their arch during the next cycle without dependency issues. It's worth making it a par-arch opt-in, because although in *theory* the compiler should never do worse than hand-coded assembler (and of course it also ought to do a lot better on platforms like Atom and PowerPC which have load-and-swap or store-and-swap instructions), that isn't always the case. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46453 for example." * tag 'byteswap-for-linus-20121219' of git://git.infradead.org/users/dwmw2/byteswap: byteorder: allow arch to opt to use GCC intrinsics for byteswapping
Diffstat (limited to 'include')
3 files changed, 26 insertions, 3 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index 412bc6c2b02..dc16a858e77 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -63,3 +63,13 @@
#define __compiletime_warning(message) __attribute__((warning(message)))
#define __compiletime_error(message) __attribute__((error(message)))
+#if __GNUC_MINOR__ >= 4
+#define __HAVE_BUILTIN_BSWAP32__
+#define __HAVE_BUILTIN_BSWAP64__
+#if __GNUC_MINOR__ >= 8 || (defined(__powerpc__) && __GNUC_MINOR__ >= 6)
+#define __HAVE_BUILTIN_BSWAP16__
diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h
index d8e636e5607..973ce10c40b 100644
--- a/include/linux/compiler-intel.h
+++ b/include/linux/compiler-intel.h
@@ -29,3 +29,10 @@
#define uninitialized_var(x) x
+#ifndef __HAVE_BUILTIN_BSWAP16__
+/* icc has this, but it's called _bswap16 */
+#define __HAVE_BUILTIN_BSWAP16__
+#define __builtin_bswap16 _bswap16
diff --git a/include/uapi/linux/swab.h b/include/uapi/linux/swab.h
index e811474724c..0e011eb91b5 100644
--- a/include/uapi/linux/swab.h
+++ b/include/uapi/linux/swab.h
@@ -45,7 +45,9 @@
static inline __attribute_const__ __u16 __fswab16(__u16 val)
-#ifdef __arch_swab16
+#ifdef __HAVE_BUILTIN_BSWAP16__
+ return __builtin_bswap16(val);
+#elif defined (__arch_swab16)
return __arch_swab16(val);
return ___constant_swab16(val);
@@ -54,7 +56,9 @@ static inline __attribute_const__ __u16 __fswab16(__u16 val)
static inline __attribute_const__ __u32 __fswab32(__u32 val)
-#ifdef __arch_swab32
+#ifdef __HAVE_BUILTIN_BSWAP32__
+ return __builtin_bswap32(val);
+#elif defined(__arch_swab32)
return __arch_swab32(val);
return ___constant_swab32(val);
@@ -63,7 +67,9 @@ static inline __attribute_const__ __u32 __fswab32(__u32 val)
static inline __attribute_const__ __u64 __fswab64(__u64 val)
-#ifdef __arch_swab64
+#ifdef __HAVE_BUILTIN_BSWAP64__
+ return __builtin_bswap64(val);
+#elif defined (__arch_swab64)
return __arch_swab64(val);
#elif defined(__SWAB_64_THRU_32__)
__u32 h = val >> 32;