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-rw-r--r--include/asm-sparc/spinlock.h238
1 files changed, 238 insertions, 0 deletions
diff --git a/include/asm-sparc/spinlock.h b/include/asm-sparc/spinlock.h
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+++ b/include/asm-sparc/spinlock.h
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+/* spinlock.h: 32-bit Sparc spinlock support.
+ *
+ * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#ifndef __SPARC_SPINLOCK_H
+#define __SPARC_SPINLOCK_H
+
+#include <linux/threads.h> /* For NR_CPUS */
+
+#ifndef __ASSEMBLY__
+
+#include <asm/psr.h>
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+struct _spinlock_debug {
+ unsigned char lock;
+ unsigned long owner_pc;
+#ifdef CONFIG_PREEMPT
+ unsigned int break_lock;
+#endif
+};
+typedef struct _spinlock_debug spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0 }
+#define spin_lock_init(lp) do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
+#define spin_is_locked(lp) (*((volatile unsigned char *)(&((lp)->lock))) != 0)
+#define spin_unlock_wait(lp) do { barrier(); } while(*(volatile unsigned char *)(&(lp)->lock))
+
+extern void _do_spin_lock(spinlock_t *lock, char *str);
+extern int _spin_trylock(spinlock_t *lock);
+extern void _do_spin_unlock(spinlock_t *lock);
+
+#define _raw_spin_trylock(lp) _spin_trylock(lp)
+#define _raw_spin_lock(lock) _do_spin_lock(lock, "spin_lock")
+#define _raw_spin_unlock(lock) _do_spin_unlock(lock)
+
+struct _rwlock_debug {
+ volatile unsigned int lock;
+ unsigned long owner_pc;
+ unsigned long reader_pc[NR_CPUS];
+#ifdef CONFIG_PREEMPT
+ unsigned int break_lock;
+#endif
+};
+typedef struct _rwlock_debug rwlock_t;
+
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, {0} }
+
+#define rwlock_init(lp) do { *(lp)= RW_LOCK_UNLOCKED; } while(0)
+
+extern void _do_read_lock(rwlock_t *rw, char *str);
+extern void _do_read_unlock(rwlock_t *rw, char *str);
+extern void _do_write_lock(rwlock_t *rw, char *str);
+extern void _do_write_unlock(rwlock_t *rw);
+
+#define _raw_read_lock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_read_lock(lock, "read_lock"); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_read_unlock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_read_unlock(lock, "read_unlock"); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_write_lock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_write_lock(lock, "write_lock"); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_write_unlock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_write_unlock(lock); \
+ local_irq_restore(flags); \
+} while(0)
+
+#else /* !CONFIG_DEBUG_SPINLOCK */
+
+typedef struct {
+ unsigned char lock;
+#ifdef CONFIG_PREEMPT
+ unsigned int break_lock;
+#endif
+} spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
+
+#define spin_lock_init(lock) (*((unsigned char *)(lock)) = 0)
+#define spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
+
+#define spin_unlock_wait(lock) \
+do { \
+ barrier(); \
+} while(*((volatile unsigned char *)lock))
+
+extern __inline__ void _raw_spin_lock(spinlock_t *lock)
+{
+ __asm__ __volatile__(
+ "\n1:\n\t"
+ "ldstub [%0], %%g2\n\t"
+ "orcc %%g2, 0x0, %%g0\n\t"
+ "bne,a 2f\n\t"
+ " ldub [%0], %%g2\n\t"
+ ".subsection 2\n"
+ "2:\n\t"
+ "orcc %%g2, 0x0, %%g0\n\t"
+ "bne,a 2b\n\t"
+ " ldub [%0], %%g2\n\t"
+ "b,a 1b\n\t"
+ ".previous\n"
+ : /* no outputs */
+ : "r" (lock)
+ : "g2", "memory", "cc");
+}
+
+extern __inline__ int _raw_spin_trylock(spinlock_t *lock)
+{
+ unsigned int result;
+ __asm__ __volatile__("ldstub [%1], %0"
+ : "=r" (result)
+ : "r" (lock)
+ : "memory");
+ return (result == 0);
+}
+
+extern __inline__ void _raw_spin_unlock(spinlock_t *lock)
+{
+ __asm__ __volatile__("stb %%g0, [%0]" : : "r" (lock) : "memory");
+}
+
+/* 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.
+ *
+ * XXX This might create some problems with my dual spinlock
+ * XXX scheme, deadlocks etc. -DaveM
+ */
+typedef struct {
+ volatile unsigned int lock;
+#ifdef CONFIG_PREEMPT
+ unsigned int break_lock;
+#endif
+} rwlock_t;
+
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
+
+#define rwlock_init(lp) do { *(lp)= RW_LOCK_UNLOCKED; } while(0)
+
+
+/* Sort of like atomic_t's on Sparc, but even more clever.
+ *
+ * ------------------------------------
+ * | 24-bit counter | wlock | rwlock_t
+ * ------------------------------------
+ * 31 8 7 0
+ *
+ * wlock signifies the one writer is in or somebody is updating
+ * counter. For a writer, if he successfully acquires the wlock,
+ * but counter is non-zero, he has to release the lock and wait,
+ * till both counter and wlock are zero.
+ *
+ * Unfortunately this scheme limits us to ~16,000,000 cpus.
+ */
+extern __inline__ void _read_lock(rwlock_t *rw)
+{
+ register rwlock_t *lp asm("g1");
+ lp = rw;
+ __asm__ __volatile__(
+ "mov %%o7, %%g4\n\t"
+ "call ___rw_read_enter\n\t"
+ " ldstub [%%g1 + 3], %%g2\n"
+ : /* no outputs */
+ : "r" (lp)
+ : "g2", "g4", "memory", "cc");
+}
+
+#define _raw_read_lock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _read_lock(lock); \
+ local_irq_restore(flags); \
+} while(0)
+
+extern __inline__ void _read_unlock(rwlock_t *rw)
+{
+ register rwlock_t *lp asm("g1");
+ lp = rw;
+ __asm__ __volatile__(
+ "mov %%o7, %%g4\n\t"
+ "call ___rw_read_exit\n\t"
+ " ldstub [%%g1 + 3], %%g2\n"
+ : /* no outputs */
+ : "r" (lp)
+ : "g2", "g4", "memory", "cc");
+}
+
+#define _raw_read_unlock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _read_unlock(lock); \
+ local_irq_restore(flags); \
+} while(0)
+
+extern __inline__ void _raw_write_lock(rwlock_t *rw)
+{
+ register rwlock_t *lp asm("g1");
+ lp = rw;
+ __asm__ __volatile__(
+ "mov %%o7, %%g4\n\t"
+ "call ___rw_write_enter\n\t"
+ " ldstub [%%g1 + 3], %%g2\n"
+ : /* no outputs */
+ : "r" (lp)
+ : "g2", "g4", "memory", "cc");
+}
+
+#define _raw_write_unlock(rw) do { (rw)->lock = 0; } while(0)
+
+#endif /* CONFIG_DEBUG_SPINLOCK */
+
+#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+
+#endif /* !(__ASSEMBLY__) */
+
+#endif /* __SPARC_SPINLOCK_H */
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