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authorEric Dumazet <dada1@cosmosbay.com>2007-02-13 13:26:21 +0100
committerAndi Kleen <andi@basil.nowhere.org>2007-02-13 13:26:21 +0100
commit5809f9d442e9dbb23859e2c37d8c47043f6b5cc9 (patch)
tree24c634f6de962734a1a6a8b94504d9555a35fcea
parent26054ed02bb20f5b2e02d92cb6f0be0e2b0196d5 (diff)
downloadlinux-5809f9d442e9dbb23859e2c37d8c47043f6b5cc9.tar.gz
[PATCH] x86-64: get rid of ARCH_HAVE_XTIME_LOCK
ARCH_HAVE_XTIME_LOCK is used by x86_64 arch .  This arch needs to place a
read only copy of xtime_lock into vsyscall page.  This read only copy is
named __xtime_lock, and xtime_lock is defined in
arch/x86_64/kernel/vmlinux.lds.S as an alias.  So the declaration of
xtime_lock in kernel/timer.c was guarded by ARCH_HAVE_XTIME_LOCK define,
defined to true on x86_64.

We can get same result with _attribute__((weak)) in the declaration. linker
should do the job.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
-rw-r--r--include/asm-x86_64/vsyscall.h5
-rw-r--r--include/linux/time.h2
-rw-r--r--kernel/timer.c4
3 files changed, 2 insertions, 9 deletions
diff --git a/include/asm-x86_64/vsyscall.h b/include/asm-x86_64/vsyscall.h
index 05cb8dd200de..0c7847165eae 100644
--- a/include/asm-x86_64/vsyscall.h
+++ b/include/asm-x86_64/vsyscall.h
@@ -56,11 +56,6 @@ extern struct vxtime_data vxtime;
 extern int vgetcpu_mode;
 extern struct timezone sys_tz;
 extern int sysctl_vsyscall;
-extern seqlock_t xtime_lock;
-
-extern int sysctl_vsyscall;
-
-#define ARCH_HAVE_XTIME_LOCK 1
 
 #endif /* __KERNEL__ */
 
diff --git a/include/linux/time.h b/include/linux/time.h
index 55cee172d723..eceb1a59b078 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -90,7 +90,7 @@ static inline struct timespec timespec_sub(struct timespec lhs,
 
 extern struct timespec xtime;
 extern struct timespec wall_to_monotonic;
-extern seqlock_t xtime_lock;
+extern seqlock_t xtime_lock __attribute__((weak));
 
 void timekeeping_init(void);
 
diff --git a/kernel/timer.c b/kernel/timer.c
index 8533c3796082..4902181e10e6 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1162,11 +1162,9 @@ static inline void calc_load(unsigned long ticks)
  * This read-write spinlock protects us from races in SMP while
  * playing with xtime and avenrun.
  */
-#ifndef ARCH_HAVE_XTIME_LOCK
-__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
+__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
 
 EXPORT_SYMBOL(xtime_lock);
-#endif
 
 /*
  * This function runs timers and the timer-tq in bottom half context.