diff options
| author | Will Deacon <will.deacon@arm.com> | 2014-07-09 19:31:28 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-07-18 12:29:35 +0100 |
| commit | bf67fd3142dc605ded9b5e063e35b47c2bb21cb1 (patch) | |
| tree | 4456902db3495ef066b7b80449c2e50e34946515 /arch/arm/include/asm/mcs_spinlock.h | |
| parent | e38361d032f12f42ddc6d8e2028f6668da696d14 (diff) | |
ARM: 8098/1: mcs lock: implement wfe-based polling for MCS locking
This patch introduces a wfe-based polling loop for spinning on contended
MCS locks and waking up corresponding waiters when the lock is released.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/mcs_spinlock.h')
| -rw-r--r-- | arch/arm/include/asm/mcs_spinlock.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mcs_spinlock.h b/arch/arm/include/asm/mcs_spinlock.h new file mode 100644 index 000000000000..f652ad65840a --- /dev/null +++ b/arch/arm/include/asm/mcs_spinlock.h @@ -0,0 +1,23 @@ +#ifndef __ASM_MCS_LOCK_H +#define __ASM_MCS_LOCK_H + +#ifdef CONFIG_SMP +#include <asm/spinlock.h> + +/* MCS spin-locking. */ +#define arch_mcs_spin_lock_contended(lock) \ +do { \ + /* Ensure prior stores are observed before we enter wfe. */ \ + smp_mb(); \ + while (!(smp_load_acquire(lock))) \ + wfe(); \ +} while (0) \ + +#define arch_mcs_spin_unlock_contended(lock) \ +do { \ + smp_store_release(lock, 1); \ + dsb_sev(); \ +} while (0) + +#endif /* CONFIG_SMP */ +#endif /* __ASM_MCS_LOCK_H */ |