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 static __inline__ void _raw_spin_lock(spinlock_t *lock)
  45 {
  46         __asm__ __volatile__(
  47 "1:     ldstub          [%0], %%g7\n"
  48 "       brnz,pn         %%g7, 2f\n"
  49 "        membar         #StoreLoad | #StoreStore\n"
  50 "       .subsection     2\n"
  51 "2:     ldub            [%0], %%g7\n"
  52 "       brnz,pt         %%g7, 2b\n"
  53 "        membar         #LoadLoad\n"
  54 "       b,a,pt          %%xcc, 1b\n"
  55 "       .previous\n"
  56         : /* no outputs */
  57         : "r" (lock)
  58         : "g7", "memory");
  59 }
  60
  61 static __inline__ int _raw_spin_trylock(spinlock_t *lock)
  62 {
  63         unsigned int result;
  64         __asm__ __volatile__("ldstub [%1], %0\n\t"
  65                              "membar #StoreLoad | #StoreStore"
  66                              : "=r" (result)
  67                              : "r" (lock)
  68                              : "memory");
  69         return (result == 0);
  70 }
  71
  72 static __inline__ void _raw_spin_unlock(spinlock_t *lock)
  73 {
  74         __asm__ __volatile__("membar    #StoreStore | #LoadStore\n\t"
  75                              "stb       %%g0, [%0]"
  76                              : /* No outputs */
  77                              : "r" (lock)
  78                              : "memory");
  79 }
  80
  81 extern void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags);
  82
  83 #else /* !(CONFIG_DEBUG_SPINLOCK) */
  84
  85 typedef struct {
  86         unsigned char lock;
  87         unsigned int owner_pc, owner_cpu;
  88 } spinlock_t;
  89 #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
  90 #define spin_lock_init(__lock)  \
  91 do {    (__lock)->lock = 0; \
  92         (__lock)->owner_pc = 0; \
  93         (__lock)->owner_cpu = 0xff; \
  94 } while(0)
  95 #define spin_is_locked(__lock)  (*((volatile unsigned char *)(&((__lock)->lock))) != 0)
  96 #define spin_unlock_wait(__lock)        \
  97 do { \
  98         membar("#LoadLoad"); \
  99 } while(*((volatile unsigned char *)(&((__lock)->lock))))
 100
 101 extern void _do_spin_lock (spinlock_t *lock, char *str);
 102 extern void _do_spin_unlock (spinlock_t *lock);
 103 extern int _spin_trylock (spinlock_t *lock);
 104
 105 #define _raw_spin_trylock(lp)   _spin_trylock(lp)
 106 #define _raw_spin_lock(lock)    _do_spin_lock(lock, "spin_lock")
 107 #define _raw_spin_unlock(lock)  _do_spin_unlock(lock)
 108 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 109
 110 #endif /* CONFIG_DEBUG_SPINLOCK */
 111
 112 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
 113
 114 #ifndef CONFIG_DEBUG_SPINLOCK
 115
 116 typedef unsigned int rwlock_t;
 117 #define RW_LOCK_UNLOCKED        0
 118 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 119 #define rwlock_is_locked(x) (*(x) != RW_LOCK_UNLOCKED)
 120
 121 extern void __read_lock(rwlock_t *);
 122 extern void __read_unlock(rwlock_t *);
 123 extern void __write_lock(rwlock_t *);
 124 extern void __write_unlock(rwlock_t *);
 125 extern int __write_trylock(rwlock_t *);
 126
 127 #define _raw_read_lock(p)       __read_lock(p)
 128 #define _raw_read_unlock(p)     __read_unlock(p)
 129 #define _raw_write_lock(p)      __write_lock(p)
 130 #define _raw_write_unlock(p)    __write_unlock(p)
 131 #define _raw_write_trylock(p)   __write_trylock(p)
 132
 133 #else /* !(CONFIG_DEBUG_SPINLOCK) */
 134
 135 typedef struct {
 136         unsigned long lock;
 137         unsigned int writer_pc, writer_cpu;
 138         unsigned int reader_pc[NR_CPUS];
 139 } rwlock_t;
 140 #define RW_LOCK_UNLOCKED        (rwlock_t) { 0, 0, 0xff, { } }
 141 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 142 #define rwlock_is_locked(x) ((x)->lock != 0)
 143
 144 extern void _do_read_lock(rwlock_t *rw, char *str);
 145 extern void _do_read_unlock(rwlock_t *rw, char *str);
 146 extern void _do_write_lock(rwlock_t *rw, char *str);
 147 extern void _do_write_unlock(rwlock_t *rw);
 148 extern int _do_write_trylock(rwlock_t *rw, char *str);
 149
 150 #define _raw_read_lock(lock) \
 151 do {    unsigned long flags; \
 152         local_irq_save(flags); \
 153         _do_read_lock(lock, "read_lock"); \
 154         local_irq_restore(flags); \
 155 } while(0)
 156
 157 #define _raw_read_unlock(lock) \
 158 do {    unsigned long flags; \
 159         local_irq_save(flags); \
 160         _do_read_unlock(lock, "read_unlock"); \
 161         local_irq_restore(flags); \
 162 } while(0)
 163
 164 #define _raw_write_lock(lock) \
 165 do {    unsigned long flags; \
 166         local_irq_save(flags); \
 167         _do_write_lock(lock, "write_lock"); \
 168         local_irq_restore(flags); \
 169 } while(0)
 170
 171 #define _raw_write_unlock(lock) \
 172 do {    unsigned long flags; \
 173         local_irq_save(flags); \
 174         _do_write_unlock(lock); \
 175         local_irq_restore(flags); \
 176 } while(0)
 177
 178 #define _raw_write_trylock(lock) \
 179 ({      unsigned long flags; \
 180         int val; \
 181         local_irq_save(flags); \
 182         val = _do_write_trylock(lock, "write_trylock"); \
 183         local_irq_restore(flags); \
 184         val; \
 185 })
 186
 187 #endif /* CONFIG_DEBUG_SPINLOCK */
 188
 189 #endif /* !(__ASSEMBLY__) */
 190
 191 #endif /* !(__SPARC64_SPINLOCK_H) */