aboutsummaryrefslogtreecommitdiff
path: root/include/asm-x86/spinlock.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/asm-x86/spinlock.h')
-rw-r--r--include/asm-x86/spinlock.h364
1 files changed, 0 insertions, 364 deletions
diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h
deleted file mode 100644
index 157ff7fab97..00000000000
--- a/include/asm-x86/spinlock.h
+++ /dev/null
@@ -1,364 +0,0 @@
-#ifndef ASM_X86__SPINLOCK_H
-#define ASM_X86__SPINLOCK_H
-
-#include <asm/atomic.h>
-#include <asm/rwlock.h>
-#include <asm/page.h>
-#include <asm/processor.h>
-#include <linux/compiler.h>
-#include <asm/paravirt.h>
-/*
- * Your basic SMP spinlocks, allowing only a single CPU anywhere
- *
- * Simple spin lock operations. There are two variants, one clears IRQ's
- * on the local processor, one does not.
- *
- * These are fair FIFO ticket locks, which are currently limited to 256
- * CPUs.
- *
- * (the type definitions are in asm/spinlock_types.h)
- */
-
-#ifdef CONFIG_X86_32
-# define LOCK_PTR_REG "a"
-# define REG_PTR_MODE "k"
-#else
-# define LOCK_PTR_REG "D"
-# define REG_PTR_MODE "q"
-#endif
-
-#if defined(CONFIG_X86_32) && \
- (defined(CONFIG_X86_OOSTORE) || defined(CONFIG_X86_PPRO_FENCE))
-/*
- * On PPro SMP or if we are using OOSTORE, we use a locked operation to unlock
- * (PPro errata 66, 92)
- */
-# define UNLOCK_LOCK_PREFIX LOCK_PREFIX
-#else
-# define UNLOCK_LOCK_PREFIX
-#endif
-
-/*
- * Ticket locks are conceptually two parts, one indicating the current head of
- * the queue, and the other indicating the current tail. The lock is acquired
- * by atomically noting the tail and incrementing it by one (thus adding
- * ourself to the queue and noting our position), then waiting until the head
- * becomes equal to the the initial value of the tail.
- *
- * We use an xadd covering *both* parts of the lock, to increment the tail and
- * also load the position of the head, which takes care of memory ordering
- * issues and should be optimal for the uncontended case. Note the tail must be
- * in the high part, because a wide xadd increment of the low part would carry
- * up and contaminate the high part.
- *
- * With fewer than 2^8 possible CPUs, we can use x86's partial registers to
- * save some instructions and make the code more elegant. There really isn't
- * much between them in performance though, especially as locks are out of line.
- */
-#if (NR_CPUS < 256)
-#define TICKET_SHIFT 8
-
-static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
-{
- short inc = 0x0100;
-
- asm volatile (
- LOCK_PREFIX "xaddw %w0, %1\n"
- "1:\t"
- "cmpb %h0, %b0\n\t"
- "je 2f\n\t"
- "rep ; nop\n\t"
- "movb %1, %b0\n\t"
- /* don't need lfence here, because loads are in-order */
- "jmp 1b\n"
- "2:"
- : "+Q" (inc), "+m" (lock->slock)
- :
- : "memory", "cc");
-}
-
-static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
-{
- int tmp, new;
-
- asm volatile("movzwl %2, %0\n\t"
- "cmpb %h0,%b0\n\t"
- "leal 0x100(%" REG_PTR_MODE "0), %1\n\t"
- "jne 1f\n\t"
- LOCK_PREFIX "cmpxchgw %w1,%2\n\t"
- "1:"
- "sete %b1\n\t"
- "movzbl %b1,%0\n\t"
- : "=&a" (tmp), "=&q" (new), "+m" (lock->slock)
- :
- : "memory", "cc");
-
- return tmp;
-}
-
-static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
-{
- asm volatile(UNLOCK_LOCK_PREFIX "incb %0"
- : "+m" (lock->slock)
- :
- : "memory", "cc");
-}
-#else
-#define TICKET_SHIFT 16
-
-static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
-{
- int inc = 0x00010000;
- int tmp;
-
- asm volatile(LOCK_PREFIX "xaddl %0, %1\n"
- "movzwl %w0, %2\n\t"
- "shrl $16, %0\n\t"
- "1:\t"
- "cmpl %0, %2\n\t"
- "je 2f\n\t"
- "rep ; nop\n\t"
- "movzwl %1, %2\n\t"
- /* don't need lfence here, because loads are in-order */
- "jmp 1b\n"
- "2:"
- : "+r" (inc), "+m" (lock->slock), "=&r" (tmp)
- :
- : "memory", "cc");
-}
-
-static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
-{
- int tmp;
- int new;
-
- asm volatile("movl %2,%0\n\t"
- "movl %0,%1\n\t"
- "roll $16, %0\n\t"
- "cmpl %0,%1\n\t"
- "leal 0x00010000(%" REG_PTR_MODE "0), %1\n\t"
- "jne 1f\n\t"
- LOCK_PREFIX "cmpxchgl %1,%2\n\t"
- "1:"
- "sete %b1\n\t"
- "movzbl %b1,%0\n\t"
- : "=&a" (tmp), "=&q" (new), "+m" (lock->slock)
- :
- : "memory", "cc");
-
- return tmp;
-}
-
-static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
-{
- asm volatile(UNLOCK_LOCK_PREFIX "incw %0"
- : "+m" (lock->slock)
- :
- : "memory", "cc");
-}
-#endif
-
-static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
-{
- int tmp = ACCESS_ONCE(lock->slock);
-
- return !!(((tmp >> TICKET_SHIFT) ^ tmp) & ((1 << TICKET_SHIFT) - 1));
-}
-
-static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
-{
- int tmp = ACCESS_ONCE(lock->slock);
-
- return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1;
-}
-
-#ifdef CONFIG_PARAVIRT
-/*
- * Define virtualization-friendly old-style lock byte lock, for use in
- * pv_lock_ops if desired.
- *
- * This differs from the pre-2.6.24 spinlock by always using xchgb
- * rather than decb to take the lock; this allows it to use a
- * zero-initialized lock structure. It also maintains a 1-byte
- * contention counter, so that we can implement
- * __byte_spin_is_contended.
- */
-struct __byte_spinlock {
- s8 lock;
- s8 spinners;
-};
-
-static inline int __byte_spin_is_locked(raw_spinlock_t *lock)
-{
- struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
- return bl->lock != 0;
-}
-
-static inline int __byte_spin_is_contended(raw_spinlock_t *lock)
-{
- struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
- return bl->spinners != 0;
-}
-
-static inline void __byte_spin_lock(raw_spinlock_t *lock)
-{
- struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
- s8 val = 1;
-
- asm("1: xchgb %1, %0\n"
- " test %1,%1\n"
- " jz 3f\n"
- " " LOCK_PREFIX "incb %2\n"
- "2: rep;nop\n"
- " cmpb $1, %0\n"
- " je 2b\n"
- " " LOCK_PREFIX "decb %2\n"
- " jmp 1b\n"
- "3:"
- : "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory");
-}
-
-static inline int __byte_spin_trylock(raw_spinlock_t *lock)
-{
- struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
- u8 old = 1;
-
- asm("xchgb %1,%0"
- : "+m" (bl->lock), "+q" (old) : : "memory");
-
- return old == 0;
-}
-
-static inline void __byte_spin_unlock(raw_spinlock_t *lock)
-{
- struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
- smp_wmb();
- bl->lock = 0;
-}
-#else /* !CONFIG_PARAVIRT */
-static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
-{
- return __ticket_spin_is_locked(lock);
-}
-
-static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
-{
- return __ticket_spin_is_contended(lock);
-}
-
-static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
-{
- __ticket_spin_lock(lock);
-}
-
-static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
-{
- return __ticket_spin_trylock(lock);
-}
-
-static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
-{
- __ticket_spin_unlock(lock);
-}
-
-static __always_inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
- unsigned long flags)
-{
- __raw_spin_lock(lock);
-}
-
-#endif /* CONFIG_PARAVIRT */
-
-static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
-{
- while (__raw_spin_is_locked(lock))
- cpu_relax();
-}
-
-/*
- * Read-write spinlocks, allowing multiple readers
- * but only one writer.
- *
- * NOTE! it is quite common to have readers in interrupts
- * but no interrupt writers. For those circumstances we
- * can "mix" irq-safe locks - any writer needs to get a
- * irq-safe write-lock, but readers can get non-irqsafe
- * read-locks.
- *
- * On x86, we implement read-write locks as a 32-bit counter
- * with the high bit (sign) being the "contended" bit.
- */
-
-/**
- * read_can_lock - would read_trylock() succeed?
- * @lock: the rwlock in question.
- */
-static inline int __raw_read_can_lock(raw_rwlock_t *lock)
-{
- return (int)(lock)->lock > 0;
-}
-
-/**
- * write_can_lock - would write_trylock() succeed?
- * @lock: the rwlock in question.
- */
-static inline int __raw_write_can_lock(raw_rwlock_t *lock)
-{
- return (lock)->lock == RW_LOCK_BIAS;
-}
-
-static inline void __raw_read_lock(raw_rwlock_t *rw)
-{
- asm volatile(LOCK_PREFIX " subl $1,(%0)\n\t"
- "jns 1f\n"
- "call __read_lock_failed\n\t"
- "1:\n"
- ::LOCK_PTR_REG (rw) : "memory");
-}
-
-static inline void __raw_write_lock(raw_rwlock_t *rw)
-{
- asm volatile(LOCK_PREFIX " subl %1,(%0)\n\t"
- "jz 1f\n"
- "call __write_lock_failed\n\t"
- "1:\n"
- ::LOCK_PTR_REG (rw), "i" (RW_LOCK_BIAS) : "memory");
-}
-
-static inline int __raw_read_trylock(raw_rwlock_t *lock)
-{
- atomic_t *count = (atomic_t *)lock;
-
- atomic_dec(count);
- if (atomic_read(count) >= 0)
- return 1;
- atomic_inc(count);
- return 0;
-}
-
-static inline int __raw_write_trylock(raw_rwlock_t *lock)
-{
- atomic_t *count = (atomic_t *)lock;
-
- if (atomic_sub_and_test(RW_LOCK_BIAS, count))
- return 1;
- atomic_add(RW_LOCK_BIAS, count);
- return 0;
-}
-
-static inline void __raw_read_unlock(raw_rwlock_t *rw)
-{
- asm volatile(LOCK_PREFIX "incl %0" :"+m" (rw->lock) : : "memory");
-}
-
-static inline void __raw_write_unlock(raw_rwlock_t *rw)
-{
- asm volatile(LOCK_PREFIX "addl %1, %0"
- : "+m" (rw->lock) : "i" (RW_LOCK_BIAS) : "memory");
-}
-
-#define _raw_spin_relax(lock) cpu_relax()
-#define _raw_read_relax(lock) cpu_relax()
-#define _raw_write_relax(lock) cpu_relax()
-
-#endif /* ASM_X86__SPINLOCK_H */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-21 05:47:01 +0000