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Commit 5809f9d4 authored by Eric Dumazet's avatar Eric Dumazet Committed by Andi Kleen
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[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: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent 26054ed0

include/asm-x86_64/vsyscall.h

+0 −5
Original line number Diff line number Diff line
@@ -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__ */

include/linux/time.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/timer.c

+1 −3
Original line number Diff line number Diff line
@@ -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.