include/asm-sparc64/spinlock.h

   1 /* spinlock.h: 64-bit Sparc spinlock support.
   2  *
   3  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
   4  */
   5
   6 #ifndef __SPARC64_SPINLOCK_H
   7 #define __SPARC64_SPINLOCK_H
   8
   9 #include <linux/config.h>
  10 #include <linux/threads.h>      /* For NR_CPUS */
  11
  12 #ifndef __ASSEMBLY__
  13
  14 /* To get debugging spinlocks which detect and catch
  15  * deadlock situations, set CONFIG_DEBUG_SPINLOCK
  16  * and rebuild your kernel.
  17  */
  18
  19 /* All of these locking primitives are expected to work properly
  20  * even in an RMO memory model, which currently is what the kernel
  21  * runs in.
  22  *
  23  * There is another issue.  Because we play games to save cycles
  24  * in the non-contention case, we need to be extra careful about
  25  * branch targets into the "spinning" code.  They live in their
  26  * own section, but the newer V9 branches have a shorter range
  27  * than the traditional 32-bit sparc branch variants.  The rule
  28  * is that the branches that go into and out of the spinner sections
  29  * must be pre-V9 branches.
  30  */
  31
  32 #ifndef CONFIG_DEBUG_SPINLOCK
  33
  34 typedef unsigned char spinlock_t;
  35 #define SPIN_LOCK_UNLOCKED      0
  36
  37 #define spin_lock_init(lock)    (*((unsigned char *)(lock)) = 0)
  38 #define spin_is_locked(lock)    (*((volatile unsigned char *)(lock)) != 0)
  39
  40 #define spin_unlock_wait(lock)  \
  41 do {    membar("#LoadLoad");    \
  42 } while(*((volatile unsigned char *)lock))
  43
  44 /* arch/sparc64/lib/spinlock.S */
  45 extern void _raw_spin_lock(spinlock_t *lock);
  46
  47 static __inline__ int _raw_spin_trylock(spinlock_t *lock)
  48 {
  49         unsigned int result;
  50         __asm__ __volatile__("ldstub [%1], %0\n\t"
  51                              "membar #StoreLoad | #StoreStore"
  52                              : "=r" (result)
  53                              : "r" (lock)
  54                              : "memory");
  55         return (result == 0);
  56 }
  57
  58 static __inline__ void _raw_spin_unlock(spinlock_t *lock)
  59 {
  60         __asm__ __volatile__("membar    #StoreStore | #LoadStore\n\t"
  61                              "stb       %%g0, [%0]"
  62                              : /* No outputs */
  63                              : "r" (lock)
  64                              : "memory");
  65 }
  66
  67 extern void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags);
  68
  69 #else /* !(CONFIG_DEBUG_SPINLOCK) */
  70
  71 typedef struct {
  72         unsigned char lock;
  73         unsigned int owner_pc, owner_cpu;
  74 } spinlock_t;
  75 #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
  76 #define spin_lock_init(__lock)  \
  77 do {    (__lock)->lock = 0; \
  78         (__lock)->owner_pc = 0; \
  79         (__lock)->owner_cpu = 0xff; \
  80 } while(0)
  81 #define spin_is_locked(__lock)  (*((volatile unsigned char *)(&((__lock)->lock))) != 0)
  82 #define spin_unlock_wait(__lock)        \
  83 do { \
  84         membar("#LoadLoad"); \
  85 } while(*((volatile unsigned char *)(&((__lock)->lock))))
  86
  87 extern void _do_spin_lock (spinlock_t *lock, char *str);
  88 extern void _do_spin_unlock (spinlock_t *lock);
  89 extern int _spin_trylock (spinlock_t *lock);
  90
  91 #define _raw_spin_trylock(lp)   _spin_trylock(lp)
  92 #define _raw_spin_lock(lock)    _do_spin_lock(lock, "spin_lock")
  93 #define _raw_spin_unlock(lock)  _do_spin_unlock(lock)
  94 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
  95
  96 #endif /* CONFIG_DEBUG_SPINLOCK */
  97
  98 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
  99
 100 #ifndef CONFIG_DEBUG_SPINLOCK
 101
 102 typedef unsigned int rwlock_t;
 103 #define RW_LOCK_UNLOCKED        0
 104 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 105 #define rwlock_is_locked(x) (*(x) != RW_LOCK_UNLOCKED)
 106
 107 extern void __read_lock(rwlock_t *);
 108 extern void __read_unlock(rwlock_t *);
 109 extern void __write_lock(rwlock_t *);
 110 extern void __write_unlock(rwlock_t *);
 111 extern int __write_trylock(rwlock_t *);
 112
 113 #define _raw_read_lock(p)       __read_lock(p)
 114 #define _raw_read_unlock(p)     __read_unlock(p)
 115 #define _raw_write_lock(p)      __write_lock(p)
 116 #define _raw_write_unlock(p)    __write_unlock(p)
 117 #define _raw_write_trylock(p)   __write_trylock(p)
 118
 119 #else /* !(CONFIG_DEBUG_SPINLOCK) */
 120
 121 typedef struct {
 122         unsigned long lock;
 123         unsigned int writer_pc, writer_cpu;
 124         unsigned int reader_pc[NR_CPUS];
 125 } rwlock_t;
 126 #define RW_LOCK_UNLOCKED        (rwlock_t) { 0, 0, 0xff, { } }
 127 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 128 #define rwlock_is_locked(x) ((x)->lock != 0)
 129
 130 extern void _do_read_lock(rwlock_t *rw, char *str);
 131 extern void _do_read_unlock(rwlock_t *rw, char *str);
 132 extern void _do_write_lock(rwlock_t *rw, char *str);
 133 extern void _do_write_unlock(rwlock_t *rw);
 134 extern int _do_write_trylock(rwlock_t *rw, char *str);
 135
 136 #define _raw_read_lock(lock) \
 137 do {    unsigned long flags; \
 138         local_irq_save(flags); \
 139         _do_read_lock(lock, "read_lock"); \
 140         local_irq_restore(flags); \
 141 } while(0)
 142
 143 #define _raw_read_unlock(lock) \
 144 do {    unsigned long flags; \
 145         local_irq_save(flags); \
 146         _do_read_unlock(lock, "read_unlock"); \
 147         local_irq_restore(flags); \
 148 } while(0)
 149
 150 #define _raw_write_lock(lock) \
 151 do {    unsigned long flags; \
 152         local_irq_save(flags); \
 153         _do_write_lock(lock, "write_lock"); \
 154         local_irq_restore(flags); \
 155 } while(0)
 156
 157 #define _raw_write_unlock(lock) \
 158 do {    unsigned long flags; \
 159         local_irq_save(flags); \
 160         _do_write_unlock(lock); \
 161         local_irq_restore(flags); \
 162 } while(0)
 163
 164 #define _raw_write_trylock(lock) \
 165 ({      unsigned long flags; \
 166         int val; \
 167         local_irq_save(flags); \
 168         val = _do_write_trylock(lock, "write_trylock"); \
 169         local_irq_restore(flags); \
 170         val; \
 171 })
 172
 173 #endif /* CONFIG_DEBUG_SPINLOCK */
 174
 175 #endif /* !(__ASSEMBLY__) */
 176
 177 #endif /* !(__SPARC64_SPINLOCK_H) */