Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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()
+14
-4
+4
-4
arch/arm64/include/asm/percpu.h
+4
-4
arch/arm64/include/asm/percpu.h
···
199
199
#define _percpu_read(pcp) \
200
200
({ \
201
201
typeof(pcp) __retval; \
202
-
preempt_disable(); \
202
+
preempt_disable_notrace(); \
203
203
__retval = (typeof(pcp))__percpu_read(raw_cpu_ptr(&(pcp)), \
204
204
sizeof(pcp)); \
205
-
preempt_enable(); \
205
+
preempt_enable_notrace(); \
206
206
__retval; \
207
207
})
208
208
209
209
#define _percpu_write(pcp, val) \
210
210
do { \
211
-
preempt_disable(); \
211
+
preempt_disable_notrace(); \
212
212
__percpu_write(raw_cpu_ptr(&(pcp)), (unsigned long)(val), \
213
213
sizeof(pcp)); \
214
-
preempt_enable(); \
214
+
preempt_enable_notrace(); \
215
215
} while(0) \
216
216
217
217
#define _pcp_protect(operation, pcp, val) \
+10
arch/arm64/include/asm/spinlock.h
+10
arch/arm64/include/asm/spinlock.h
···
363
363
#define arch_read_relax(lock) cpu_relax()
364
364
#define arch_write_relax(lock) cpu_relax()
365
365
366
+
/*
367
+
* Accesses appearing in program order before a spin_lock() operation
368
+
* can be reordered with accesses inside the critical section, by virtue
369
+
* of arch_spin_lock being constructed using acquire semantics.
370
+
*
371
+
* In cases where this is problematic (e.g. try_to_wake_up), an
372
+
* smp_mb__before_spinlock() can restore the required ordering.
373
+
*/
374
+
#define smp_mb__before_spinlock() smp_mb()
375
+
366
376
#endif /* __ASM_SPINLOCK_H */