Commit:     4ecbca8554d0f643351ee07d3284138a5e85ba81
Parent:     9cdcaa2c9330432bfe891d40f2d914b80bbcf9f3
Author:     Serge Belyshev <[EMAIL PROTECTED]>
AuthorDate: Thu Oct 4 23:10:04 2007 +0200
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Oct 5 08:04:35 2007 -0700

    Remove unnecessary cast in prefetch()
    It is ok to call prefetch() function with NULL argument, as specifically
    commented in include/linux/prefetch.h.  But in standard C, it is invalid
    to dereference NULL pointer (see C99 standard paragraph 4 and
    note #84).
    prefetch() has a memory reference for its argument.
    Newer gcc versions (4.3 and above) will use that to conclude that "x"
    argument is non-null and thus wreaking havok everywhere prefetch() was
    Fixed by removing cast and changing asm constraint.
    [ It seems in theory gcc 4.2 could miscompile this too; although no
      cases known.  In 2.6.24 we should probably switch to
      __builtin_prefetch() instead, but this is a simpler fix for now.
                                -- AK ]
    Signed-off-by: Serge Belyshev <[EMAIL PROTECTED]>
    Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 include/asm-x86_64/processor.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h
index 1952517..31f579b 100644
--- a/include/asm-x86_64/processor.h
+++ b/include/asm-x86_64/processor.h
@@ -371,7 +371,7 @@ static inline void sync_core(void)
 static inline void prefetch(void *x) 
-       asm volatile("prefetcht0 %0" :: "m" (*(unsigned long *)x));
+       asm volatile("prefetcht0 (%0)" :: "r" (x));
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