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authorLinus Torvalds <torvalds@linux-foundation.org>2009-08-03 14:08:48 +0900
committerTejun Heo <tj@kernel.org>2009-08-04 01:28:52 +0900
commited8d9adf357ec331603fa1049510399812cea7e5 (patch)
treecc6eae948bf4652b9d87aee796ae78cc6287ac36 /arch/x86/include/asm/thread_info.h
parenta33a052f19a21d727847391c8c1aff3fb221c472 (diff)
x86, percpu: Add 'percpu_read_stable()' interface for cacheable accesses
This is very useful for some common things like 'get_current()' and 'get_thread_info()', which can be used multiple times in a function, and where the result is cacheable. tj: Added the magical undocumented "P" modifier to UP __percpu_arg() to force gcc to dereference the pointer value passed in via the "p" input constraint. Without this, percpu_read_stable() returns the address of the percpu variable. Also added comment explaining the difference between percpu_read() and percpu_read_stable(). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/thread_info.h')
-rw-r--r--arch/x86/include/asm/thread_info.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index fad7d40b75f..a1bb5a114bf 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -213,7 +213,7 @@ DECLARE_PER_CPU(unsigned long, kernel_stack);
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
- ti = (void *)(percpu_read(kernel_stack) +
+ ti = (void *)(percpu_read_stable(kernel_stack) +
KERNEL_STACK_OFFSET - THREAD_SIZE);
return ti;
}