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 #else /* !(CONFIG_DEBUG_SPINLOCK) */
  82
  83 typedef struct {
  84         unsigned char lock;
  85         unsigned int owner_pc, owner_cpu;
  86 } spinlock_t;
  87 #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
  88 #define spin_lock_init(__lock)  \
  89 do {    (__lock)->lock = 0; \
  90         (__lock)->owner_pc = 0; \
  91         (__lock)->owner_cpu = 0xff; \
  92 } while(0)
  93 #define spin_is_locked(__lock)  (*((volatile unsigned char *)(&((__lock)->lock))) != 0)
  94 #define spin_unlock_wait(__lock)        \
  95 do { \
  96         membar("#LoadLoad"); \
  97 } while(*((volatile unsigned char *)(&((__lock)->lock))))
  98
  99 extern void _do_spin_lock (spinlock_t *lock, char *str);
 100 extern void _do_spin_unlock (spinlock_t *lock);
 101 extern int _spin_trylock (spinlock_t *lock);
 102
 103 #define _raw_spin_trylock(lp)   _spin_trylock(lp)
 104 #define _raw_spin_lock(lock)    _do_spin_lock(lock, "spin_lock")
 105 #define _raw_spin_unlock(lock)  _do_spin_unlock(lock)
 106
 107 #endif /* CONFIG_DEBUG_SPINLOCK */
 108
 109 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
 110
 111 #ifndef CONFIG_DEBUG_SPINLOCK
 112
 113 typedef unsigned int rwlock_t;
 114 #define RW_LOCK_UNLOCKED        0
 115 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 116 #define rwlock_is_locked(x) (*(x) != RW_LOCK_UNLOCKED)
 117
 118 extern void __read_lock(rwlock_t *);
 119 extern void __read_unlock(rwlock_t *);
 120 extern void __write_lock(rwlock_t *);
 121 extern void __write_unlock(rwlock_t *);
 122 extern int __write_trylock(rwlock_t *);
 123
 124 #define _raw_read_lock(p)       __read_lock(p)
 125 #define _raw_read_unlock(p)     __read_unlock(p)
 126 #define _raw_write_lock(p)      __write_lock(p)
 127 #define _raw_write_unlock(p)    __write_unlock(p)
 128 #define _raw_write_trylock(p)   __write_trylock(p)
 129
 130 #else /* !(CONFIG_DEBUG_SPINLOCK) */
 131
 132 typedef struct {
 133         unsigned long lock;
 134         unsigned int writer_pc, writer_cpu;
 135         unsigned int reader_pc[NR_CPUS];
 136 } rwlock_t;
 137 #define RW_LOCK_UNLOCKED        (rwlock_t) { 0, 0, 0xff, { } }
 138 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 139 #define rwlock_is_locked(x) ((x)->lock != 0)
 140
 141 extern void _do_read_lock(rwlock_t *rw, char *str);
 142 extern void _do_read_unlock(rwlock_t *rw, char *str);
 143 extern void _do_write_lock(rwlock_t *rw, char *str);
 144 extern void _do_write_unlock(rwlock_t *rw);
 145
 146 #define _raw_read_lock(lock) \
 147 do {    unsigned long flags; \
 148         local_irq_save(flags); \
 149         _do_read_lock(lock, "read_lock"); \
 150         local_irq_restore(flags); \
 151 } while(0)
 152
 153 #define _raw_read_unlock(lock) \
 154 do {    unsigned long flags; \
 155         local_irq_save(flags); \
 156         _do_read_unlock(lock, "read_unlock"); \
 157         local_irq_restore(flags); \
 158 } while(0)
 159
 160 #define _raw_write_lock(lock) \
 161 do {    unsigned long flags; \
 162         local_irq_save(flags); \
 163         _do_write_lock(lock, "write_lock"); \
 164         local_irq_restore(flags); \
 165 } while(0)
 166
 167 #define _raw_write_unlock(lock) \
 168 do {    unsigned long flags; \
 169         local_irq_save(flags); \
 170         _do_write_unlock(lock); \
 171         local_irq_restore(flags); \
 172 } while(0)
 173
 174 #endif /* CONFIG_DEBUG_SPINLOCK */
 175
 176 #endif /* !(__ASSEMBLY__) */
 177
 178 #endif /* !(__SPARC64_SPINLOCK_H) */