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Commit e45eeb43 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 

Pull arm64 fixes from Catalin Marinas:

 - smp_mb__before_spinlock() changed to smp_mb() on arm64 since the
   generic definition to smp_wmb() is not sufficient

 - avoid a recursive loop with the graph tracer by using using
   preempt_(enable|disable)_notrace in _percpu_(read|write)

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: use preempt_disable_notrace in _percpu_read/write
  arm64: spinlocks: implement smp_mb__before_spinlock() as smp_mb()
parents 2771fc8e 2b974344

arch/arm64/include/asm/percpu.h

+4 −4
Original line number Diff line number Diff line
@@ -199,19 +199,19 @@ static inline unsigned long __percpu_xchg(void *ptr, unsigned long val, 
#define _percpu_read(pcp)						\

({									\

	typeof(pcp) __retval;						\

	preempt_disable();						\

	preempt_disable_notrace();					\

	__retval = (typeof(pcp))__percpu_read(raw_cpu_ptr(&(pcp)), 	\

					      sizeof(pcp));		\

	preempt_enable();						\

	preempt_enable_notrace();					\

	__retval;							\

})



#define _percpu_write(pcp, val)						\

do {									\

	preempt_disable();						\

	preempt_disable_notrace();					\

	__percpu_write(raw_cpu_ptr(&(pcp)), (unsigned long)(val), 	\

				sizeof(pcp));				\

	preempt_enable();						\

	preempt_enable_notrace();					\

} while(0)								\



#define _pcp_protect(operation, pcp, val)			\

arch/arm64/include/asm/spinlock.h

+10 −0
Original line number Diff line number Diff line
@@ -363,4 +363,14 @@ static inline int arch_read_trylock(arch_rwlock_t *rw) 
#define arch_read_relax(lock)	cpu_relax()

#define arch_write_relax(lock)	cpu_relax()



/*

 * Accesses appearing in program order before a spin_lock() operation

 * can be reordered with accesses inside the critical section, by virtue

 * of arch_spin_lock being constructed using acquire semantics.

 *

 * In cases where this is problematic (e.g. try_to_wake_up), an

 * smp_mb__before_spinlock() can restore the required ordering.

 */

#define smp_mb__before_spinlock()	smp_mb()



#endif /* __ASM_SPINLOCK_H */