mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-01-13 08:46:40 +07:00
726328d92a
This patch updates/fixes all spin_unlock_wait() implementations. The update is in semantics; where it previously was only a control dependency, we now upgrade to a full load-acquire to match the store-release from the spin_unlock() we waited on. This ensures that when spin_unlock_wait() returns, we're guaranteed to observe the full critical section we waited on. This fixes a number of spin_unlock_wait() users that (not unreasonably) rely on this. I also fixed a number of ticket lock versions to only wait on the current lock holder, instead of for a full unlock, as this is sufficient. Furthermore; again for ticket locks; I added an smp_rmb() in between the initial ticket load and the spin loop testing the current value because I could not convince myself the address dependency is sufficient, esp. if the loads are of different sizes. I'm more than happy to remove this smp_rmb() again if people are certain the address dependency does indeed work as expected. Note: PPC32 will be fixed independently Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: chris@zankel.net Cc: cmetcalf@mellanox.com Cc: davem@davemloft.net Cc: dhowells@redhat.com Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: linux@armlinux.org.uk Cc: mpe@ellerman.id.au Cc: ralf@linux-mips.org Cc: realmz6@gmail.com Cc: rkuo@codeaurora.org Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Cc: vgupta@synopsys.com Cc: ysato@users.sourceforge.jp Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
107 lines
2.5 KiB
C
107 lines
2.5 KiB
C
/*
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* Copyright 2004-2009 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#ifndef __BFIN_SPINLOCK_H
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#define __BFIN_SPINLOCK_H
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#ifndef CONFIG_SMP
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# include <asm-generic/spinlock.h>
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#else
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#include <linux/atomic.h>
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#include <asm/processor.h>
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#include <asm/barrier.h>
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asmlinkage int __raw_spin_is_locked_asm(volatile int *ptr);
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asmlinkage void __raw_spin_lock_asm(volatile int *ptr);
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asmlinkage int __raw_spin_trylock_asm(volatile int *ptr);
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asmlinkage void __raw_spin_unlock_asm(volatile int *ptr);
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asmlinkage void __raw_read_lock_asm(volatile int *ptr);
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asmlinkage int __raw_read_trylock_asm(volatile int *ptr);
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asmlinkage void __raw_read_unlock_asm(volatile int *ptr);
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asmlinkage void __raw_write_lock_asm(volatile int *ptr);
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asmlinkage int __raw_write_trylock_asm(volatile int *ptr);
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asmlinkage void __raw_write_unlock_asm(volatile int *ptr);
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static inline int arch_spin_is_locked(arch_spinlock_t *lock)
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{
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return __raw_spin_is_locked_asm(&lock->lock);
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}
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static inline void arch_spin_lock(arch_spinlock_t *lock)
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{
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__raw_spin_lock_asm(&lock->lock);
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}
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#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
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static inline int arch_spin_trylock(arch_spinlock_t *lock)
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{
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return __raw_spin_trylock_asm(&lock->lock);
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}
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static inline void arch_spin_unlock(arch_spinlock_t *lock)
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{
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__raw_spin_unlock_asm(&lock->lock);
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}
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static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
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{
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smp_cond_load_acquire(&lock->lock, !VAL);
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}
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static inline int arch_read_can_lock(arch_rwlock_t *rw)
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{
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return __raw_uncached_fetch_asm(&rw->lock) > 0;
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}
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static inline int arch_write_can_lock(arch_rwlock_t *rw)
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{
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return __raw_uncached_fetch_asm(&rw->lock) == RW_LOCK_BIAS;
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}
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static inline void arch_read_lock(arch_rwlock_t *rw)
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{
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__raw_read_lock_asm(&rw->lock);
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}
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#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
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static inline int arch_read_trylock(arch_rwlock_t *rw)
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{
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return __raw_read_trylock_asm(&rw->lock);
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}
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static inline void arch_read_unlock(arch_rwlock_t *rw)
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{
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__raw_read_unlock_asm(&rw->lock);
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}
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static inline void arch_write_lock(arch_rwlock_t *rw)
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{
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__raw_write_lock_asm(&rw->lock);
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}
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#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
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static inline int arch_write_trylock(arch_rwlock_t *rw)
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{
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return __raw_write_trylock_asm(&rw->lock);
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}
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static inline void arch_write_unlock(arch_rwlock_t *rw)
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{
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__raw_write_unlock_asm(&rw->lock);
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}
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#define arch_spin_relax(lock) cpu_relax()
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#define arch_read_relax(lock) cpu_relax()
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#define arch_write_relax(lock) cpu_relax()
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#endif
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#endif /* !__BFIN_SPINLOCK_H */
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