Initial import

1 files changed, 296 insertions, 0 deletions

diff --git a/arch/ia64/include/asm/spinlock.h b/arch/ia64/include/asm/spinlock.h
new file mode 100644
index 000000000..45698cd15
--- /dev/null
+++ b/arch/ia64/include/asm/spinlock.h
@@ -0,0 +1,296 @@
+#ifndef _ASM_IA64_SPINLOCK_H
+#define _ASM_IA64_SPINLOCK_H
+
+/*
+ * Copyright (C) 1998-2003 Hewlett-Packard Co
+ *	David Mosberger-Tang <davidm@hpl.hp.com>
+ * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
+ *
+ * This file is used for SMP configurations only.
+ */
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+
+#include <linux/atomic.h>
+#include <asm/intrinsics.h>
+
+#define arch_spin_lock_init(x)			((x)->lock = 0)
+
+/*
+ * 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.
+ * The pad bits in the middle are used to prevent the next_ticket number
+ * overflowing into the now_serving number.
+ *
+ *   31             17  16    15  14                    0
+ *  +----------------------------------------------------+
+ *  |  now_serving     | padding |   next_ticket         |
+ *  +----------------------------------------------------+
+ */
+
+#define TICKET_SHIFT	17
+#define TICKET_BITS	15
+#define	TICKET_MASK	((1 << TICKET_BITS) - 1)
+
+static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock)
+{
+	int	*p = (int *)&lock->lock, ticket, serve;
+
+	ticket = ia64_fetchadd(1, p, acq);
+
+	if (!(((ticket >> TICKET_SHIFT) ^ ticket) & TICKET_MASK))
+		return;
+
+	ia64_invala();
+
+	for (;;) {
+		asm volatile ("ld4.c.nc %0=[%1]" : "=r"(serve) : "r"(p) : "memory");
+
+		if (!(((serve >> TICKET_SHIFT) ^ ticket) & TICKET_MASK))
+			return;
+		cpu_relax();
+	}
+}
+
+static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock)
+{
+	int tmp = ACCESS_ONCE(lock->lock);
+
+	if (!(((tmp >> TICKET_SHIFT) ^ tmp) & TICKET_MASK))
+		return ia64_cmpxchg(acq, &lock->lock, tmp, tmp + 1, sizeof (tmp)) == tmp;
+	return 0;
+}
+
+static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock)
+{
+	unsigned short	*p = (unsigned short *)&lock->lock + 1, tmp;
+
+	asm volatile ("ld2.bias %0=[%1]" : "=r"(tmp) : "r"(p));
+	ACCESS_ONCE(*p) = (tmp + 2) & ~1;
+}
+
+static __always_inline void __ticket_spin_unlock_wait(arch_spinlock_t *lock)
+{
+	int	*p = (int *)&lock->lock, ticket;
+
+	ia64_invala();
+
+	for (;;) {
+		asm volatile ("ld4.c.nc %0=[%1]" : "=r"(ticket) : "r"(p) : "memory");
+		if (!(((ticket >> TICKET_SHIFT) ^ ticket) & TICKET_MASK))
+			return;
+		cpu_relax();
+	}
+}
+
+static inline int __ticket_spin_is_locked(arch_spinlock_t *lock)
+{
+	long tmp = ACCESS_ONCE(lock->lock);
+
+	return !!(((tmp >> TICKET_SHIFT) ^ tmp) & TICKET_MASK);
+}
+
+static inline int __ticket_spin_is_contended(arch_spinlock_t *lock)
+{
+	long tmp = ACCESS_ONCE(lock->lock);
+
+	return ((tmp - (tmp >> TICKET_SHIFT)) & TICKET_MASK) > 1;
+}
+
+static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock)
+{
+	return !(((lock.lock >> TICKET_SHIFT) ^ lock.lock) & TICKET_MASK);
+}
+
+static inline int arch_spin_is_locked(arch_spinlock_t *lock)
+{
+	return __ticket_spin_is_locked(lock);
+}
+
+static inline int arch_spin_is_contended(arch_spinlock_t *lock)
+{
+	return __ticket_spin_is_contended(lock);
+}
+#define arch_spin_is_contended	arch_spin_is_contended
+
+static __always_inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+	__ticket_spin_lock(lock);
+}
+
+static __always_inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+	return __ticket_spin_trylock(lock);
+}
+
+static __always_inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+	__ticket_spin_unlock(lock);
+}
+
+static __always_inline void arch_spin_lock_flags(arch_spinlock_t *lock,
+						  unsigned long flags)
+{
+	arch_spin_lock(lock);
+}
+
+static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
+{
+	__ticket_spin_unlock_wait(lock);
+}
+
+#define arch_read_can_lock(rw)		(*(volatile int *)(rw) >= 0)
+#define arch_write_can_lock(rw)	(*(volatile int *)(rw) == 0)
+
+#ifdef ASM_SUPPORTED
+
+static __always_inline void
+arch_read_lock_flags(arch_rwlock_t *lock, unsigned long flags)
+{
+	__asm__ __volatile__ (
+		"tbit.nz p6, p0 = %1,%2\n"
+		"br.few 3f\n"
+		"1:\n"
+		"fetchadd4.rel r2 = [%0], -1;;\n"
+		"(p6) ssm psr.i\n"
+		"2:\n"
+		"hint @pause\n"
+		"ld4 r2 = [%0];;\n"
+		"cmp4.lt p7,p0 = r2, r0\n"
+		"(p7) br.cond.spnt.few 2b\n"
+		"(p6) rsm psr.i\n"
+		";;\n"
+		"3:\n"
+		"fetchadd4.acq r2 = [%0], 1;;\n"
+		"cmp4.lt p7,p0 = r2, r0\n"
+		"(p7) br.cond.spnt.few 1b\n"
+		: : "r"(lock), "r"(flags), "i"(IA64_PSR_I_BIT)
+		: "p6", "p7", "r2", "memory");
+}
+
+#define arch_read_lock(lock) arch_read_lock_flags(lock, 0)
+
+#else /* !ASM_SUPPORTED */
+
+#define arch_read_lock_flags(rw, flags) arch_read_lock(rw)
+
+#define arch_read_lock(rw)								\
+do {											\
+	arch_rwlock_t *__read_lock_ptr = (rw);						\
+											\
+	while (unlikely(ia64_fetchadd(1, (int *) __read_lock_ptr, acq) < 0)) {		\
+		ia64_fetchadd(-1, (int *) __read_lock_ptr, rel);			\
+		while (*(volatile int *)__read_lock_ptr < 0)				\
+			cpu_relax();							\
+	}										\
+} while (0)
+
+#endif /* !ASM_SUPPORTED */
+
+#define arch_read_unlock(rw)					\
+do {								\
+	arch_rwlock_t *__read_lock_ptr = (rw);			\
+	ia64_fetchadd(-1, (int *) __read_lock_ptr, rel);	\
+} while (0)
+
+#ifdef ASM_SUPPORTED
+
+static __always_inline void
+arch_write_lock_flags(arch_rwlock_t *lock, unsigned long flags)
+{
+	__asm__ __volatile__ (
+		"tbit.nz p6, p0 = %1, %2\n"
+		"mov ar.ccv = r0\n"
+		"dep r29 = -1, r0, 31, 1\n"
+		"br.few 3f;;\n"
+		"1:\n"
+		"(p6) ssm psr.i\n"
+		"2:\n"
+		"hint @pause\n"
+		"ld4 r2 = [%0];;\n"
+		"cmp4.eq p0,p7 = r0, r2\n"
+		"(p7) br.cond.spnt.few 2b\n"
+		"(p6) rsm psr.i\n"
+		";;\n"
+		"3:\n"
+		"cmpxchg4.acq r2 = [%0], r29, ar.ccv;;\n"
+		"cmp4.eq p0,p7 = r0, r2\n"
+		"(p7) br.cond.spnt.few 1b;;\n"
+		: : "r"(lock), "r"(flags), "i"(IA64_PSR_I_BIT)
+		: "ar.ccv", "p6", "p7", "r2", "r29", "memory");
+}
+
+#define arch_write_lock(rw) arch_write_lock_flags(rw, 0)
+
+#define arch_write_trylock(rw)							\
+({										\
+	register long result;							\
+										\
+	__asm__ __volatile__ (							\
+		"mov ar.ccv = r0\n"						\
+		"dep r29 = -1, r0, 31, 1;;\n"					\
+		"cmpxchg4.acq %0 = [%1], r29, ar.ccv\n"				\
+		: "=r"(result) : "r"(rw) : "ar.ccv", "r29", "memory");		\
+	(result == 0);								\
+})
+
+static inline void arch_write_unlock(arch_rwlock_t *x)
+{
+	u8 *y = (u8 *)x;
+	barrier();
+	asm volatile ("st1.rel.nta [%0] = r0\n\t" :: "r"(y+3) : "memory" );
+}
+
+#else /* !ASM_SUPPORTED */
+
+#define arch_write_lock_flags(l, flags) arch_write_lock(l)
+
+#define arch_write_lock(l)								\
+({											\
+	__u64 ia64_val, ia64_set_val = ia64_dep_mi(-1, 0, 31, 1);			\
+	__u32 *ia64_write_lock_ptr = (__u32 *) (l);					\
+	do {										\
+		while (*ia64_write_lock_ptr)						\
+			ia64_barrier();							\
+		ia64_val = ia64_cmpxchg4_acq(ia64_write_lock_ptr, ia64_set_val, 0);	\
+	} while (ia64_val);								\
+})
+
+#define arch_write_trylock(rw)						\
+({									\
+	__u64 ia64_val;							\
+	__u64 ia64_set_val = ia64_dep_mi(-1, 0, 31,1);			\
+	ia64_val = ia64_cmpxchg4_acq((__u32 *)(rw), ia64_set_val, 0);	\
+	(ia64_val == 0);						\
+})
+
+static inline void arch_write_unlock(arch_rwlock_t *x)
+{
+	barrier();
+	x->write_lock = 0;
+}
+
+#endif /* !ASM_SUPPORTED */
+
+static inline int arch_read_trylock(arch_rwlock_t *x)
+{
+	union {
+		arch_rwlock_t lock;
+		__u32 word;
+	} old, new;
+	old.lock = new.lock = *x;
+	old.lock.write_lock = new.lock.write_lock = 0;
+	++new.lock.read_counter;
+	return (u32)ia64_cmpxchg4_acq((__u32 *)(x), new.word, old.word) == old.word;
+}
+
+#define arch_spin_relax(lock)	cpu_relax()
+#define arch_read_relax(lock)	cpu_relax()
+#define arch_write_relax(lock)	cpu_relax()
+
+#endif /*  _ASM_IA64_SPINLOCK_H */