From 630017f420f111e0c0332dbd99df30ebb8fed207 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Wed, 26 Mar 2014 13:38:36 +0000 Subject: [PATCH] xen: x86 & generic: change to __builtin_prefetch() Quoting Andi Kleen in Linux b483570a13be from 2007: gcc 3.2+ supports __builtin_prefetch, so it's possible to use it on all architectures. Change the generic fallback in linux/prefetch.h to use it instead of noping it out. gcc should do the right thing when the architecture doesn't support prefetching Undefine the x86-64 inline assembler version and use the fallback. ARM wants to use the builtins. Fix a pair of spelling errors, one of which was from Lucas De Marchi in the Linux tree. Signed-off-by: Ian Campbell Reviewed-by: Jan Beulich Cc: Keir Fraser Acked-by: Tim Deegan --- xen/include/xen/prefetch.h | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/xen/include/xen/prefetch.h b/xen/include/xen/prefetch.h index 8d7d3ffeb4..ba7399828e 100644 --- a/xen/include/xen/prefetch.h +++ b/xen/include/xen/prefetch.h @@ -28,24 +28,17 @@ prefetchw(x) - prefetches the cacheline at "x" for write spin_lock_prefetch(x) - prefectches the spinlock *x for taking - there is also PREFETCH_STRIDE which is the architecure-prefered + there is also PREFETCH_STRIDE which is the architecture-preferred "lookahead" size for prefetching streamed operations. */ -/* - * These cannot be do{}while(0) macros. See the mental gymnastics in - * the loop macro. - */ - #ifndef ARCH_HAS_PREFETCH -#define ARCH_HAS_PREFETCH -static inline void prefetch(const void *x) {;} +#define prefetch(x) __builtin_prefetch(x) #endif #ifndef ARCH_HAS_PREFETCHW -#define ARCH_HAS_PREFETCHW -static inline void prefetchw(const void *x) {;} +#define prefetchw(x) __builtin_prefetch(x,1) #endif #ifndef ARCH_HAS_SPINLOCK_PREFETCH -- 2.30.2