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 struct {
  35         volatile unsigned char lock;
  36 #ifdef CONFIG_PREEMPT
  37         unsigned int break_lock;
  38 #endif
  39 } spinlock_t;
  40 #define SPIN_LOCK_UNLOCKED      (spinlock_t) {0,}
  41
  42 #define spin_lock_init(lp)      do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
  43 #define spin_is_locked(lp)  ((lp)->lock != 0)
  44
  45 #define spin_unlock_wait(lp)    \
  46 do {    membar("#LoadLoad");    \
  47 } while((lp)->lock)
  48
  49 static inline void _raw_spin_lock(spinlock_t *lock)
  50 {
  51         unsigned long tmp;
  52
  53         __asm__ __volatile__(
  54 "1:     ldstub          [%1], %0\n"
  55 "       brnz,pn         %0, 2f\n"
  56 "        membar         #StoreLoad | #StoreStore\n"
  57 "       .subsection     2\n"
  58 "2:     ldub            [%1], %0\n"
  59 "       brnz,pt         %0, 2b\n"
  60 "        membar         #LoadLoad\n"
  61 "       ba,a,pt         %%xcc, 1b\n"
  62 "       .previous"
  63         : "=&r" (tmp)
  64         : "r" (lock)
  65         : "memory");
  66 }
  67
  68 static inline int _raw_spin_trylock(spinlock_t *lock)
  69 {
  70         unsigned long result;
  71
  72         __asm__ __volatile__(
  73 "       ldstub          [%1], %0\n"
  74 "       membar          #StoreLoad | #StoreStore"
  75         : "=r" (result)
  76         : "r" (lock)
  77         : "memory");
  78
  79         return (result == 0UL);
  80 }
  81
  82 static inline void _raw_spin_unlock(spinlock_t *lock)
  83 {
  84         __asm__ __volatile__(
  85 "       membar          #StoreStore | #LoadStore\n"
  86 "       stb             %%g0, [%0]"
  87         : /* No outputs */
  88         : "r" (lock)
  89         : "memory");
  90 }
  91
  92 static inline void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
  93 {
  94         unsigned long tmp1, tmp2;
  95
  96         __asm__ __volatile__(
  97 "1:     ldstub          [%2], %0\n"
  98 "       brnz,pn         %0, 2f\n"
  99 "       membar          #StoreLoad | #StoreStore\n"
 100 "       .subsection     2\n"
 101 "2:     rdpr            %%pil, %1\n"
 102 "       wrpr            %3, %%pil\n"
 103 "3:     ldub            [%2], %0\n"
 104 "       brnz,pt         %0, 3b\n"
 105 "       membar          #LoadLoad\n"
 106 "       ba,pt           %%xcc, 1b\n"
 107 "       wrpr            %1, %%pil\n"
 108 "       .previous"
 109         : "=&r" (tmp1), "=&r" (tmp2)
 110         : "r"(lock), "r"(flags)
 111         : "memory");
 112 }
 113
 114 #else /* !(CONFIG_DEBUG_SPINLOCK) */
 115
 116 typedef struct {
 117         volatile unsigned char lock;
 118         unsigned int owner_pc, owner_cpu;
 119 #ifdef CONFIG_PREEMPT
 120         unsigned int break_lock;
 121 #endif
 122 } spinlock_t;
 123 #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
 124 #define spin_lock_init(lp)      do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
 125 #define spin_is_locked(__lock)  ((__lock)->lock != 0)
 126 #define spin_unlock_wait(__lock)        \
 127 do { \
 128         membar("#LoadLoad"); \
 129 } while((__lock)->lock)
 130
 131 extern void _do_spin_lock (spinlock_t *lock, char *str);
 132 extern void _do_spin_unlock (spinlock_t *lock);
 133 extern int _do_spin_trylock (spinlock_t *lock);
 134
 135 #define _raw_spin_trylock(lp)   _do_spin_trylock(lp)
 136 #define _raw_spin_lock(lock)    _do_spin_lock(lock, "spin_lock")
 137 #define _raw_spin_unlock(lock)  _do_spin_unlock(lock)
 138 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 139
 140 #endif /* CONFIG_DEBUG_SPINLOCK */
 141
 142 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
 143
 144 #ifndef CONFIG_DEBUG_SPINLOCK
 145
 146 typedef struct {
 147         volatile unsigned int lock;
 148 #ifdef CONFIG_PREEMPT
 149         unsigned int break_lock;
 150 #endif
 151 } rwlock_t;
 152 #define RW_LOCK_UNLOCKED        (rwlock_t) {0,}
 153 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 154
 155 static void inline __read_lock(rwlock_t *lock)
 156 {
 157         unsigned long tmp1, tmp2;
 158
 159         __asm__ __volatile__ (
 160 "1:     ldsw            [%2], %0\n"
 161 "       brlz,pn         %0, 2f\n"
 162 "4:      add            %0, 1, %1\n"
 163 "       cas             [%2], %0, %1\n"
 164 "       cmp             %0, %1\n"
 165 "       bne,pn          %%icc, 1b\n"
 166 "        membar         #StoreLoad | #StoreStore\n"
 167 "       .subsection     2\n"
 168 "2:     ldsw            [%2], %0\n"
 169 "       brlz,pt         %0, 2b\n"
 170 "        membar         #LoadLoad\n"
 171 "       ba,a,pt         %%xcc, 4b\n"
 172 "       .previous"
 173         : "=&r" (tmp1), "=&r" (tmp2)
 174         : "r" (lock)
 175         : "memory");
 176 }
 177
 178 static void inline __read_unlock(rwlock_t *lock)
 179 {
 180         unsigned long tmp1, tmp2;
 181
 182         __asm__ __volatile__(
 183 "       membar  #StoreLoad | #LoadLoad\n"
 184 "1:     lduw    [%2], %0\n"
 185 "       sub     %0, 1, %1\n"
 186 "       cas     [%2], %0, %1\n"
 187 "       cmp     %0, %1\n"
 188 "       bne,pn  %%xcc, 1b\n"
 189 "        nop"
 190         : "=&r" (tmp1), "=&r" (tmp2)
 191         : "r" (lock)
 192         : "memory");
 193 }
 194
 195 static void inline __write_lock(rwlock_t *lock)
 196 {
 197         unsigned long mask, tmp1, tmp2;
 198
 199         mask = 0x80000000UL;
 200
 201         __asm__ __volatile__(
 202 "1:     lduw            [%2], %0\n"
 203 "       brnz,pn         %0, 2f\n"
 204 "4:      or             %0, %3, %1\n"
 205 "       cas             [%2], %0, %1\n"
 206 "       cmp             %0, %1\n"
 207 "       bne,pn          %%icc, 1b\n"
 208 "        membar         #StoreLoad | #StoreStore\n"
 209 "       .subsection     2\n"
 210 "2:     lduw            [%2], %0\n"
 211 "       brnz,pt         %0, 2b\n"
 212 "        membar         #LoadLoad\n"
 213 "       ba,a,pt         %%xcc, 4b\n"
 214 "       .previous"
 215         : "=&r" (tmp1), "=&r" (tmp2)
 216         : "r" (lock), "r" (mask)
 217         : "memory");
 218 }
 219
 220 static void inline __write_unlock(rwlock_t *lock)
 221 {
 222         __asm__ __volatile__(
 223 "       membar          #LoadStore | #StoreStore\n"
 224 "       stw             %%g0, [%0]"
 225         : /* no outputs */
 226         : "r" (lock)
 227         : "memory");
 228 }
 229
 230 static int inline __write_trylock(rwlock_t *lock)
 231 {
 232         unsigned long mask, tmp1, tmp2, result;
 233
 234         mask = 0x80000000UL;
 235
 236         __asm__ __volatile__(
 237 "       mov             0, %2\n"
 238 "1:     lduw            [%3], %0\n"
 239 "       brnz,pn         %0, 2f\n"
 240 "        or             %0, %4, %1\n"
 241 "       cas             [%3], %0, %1\n"
 242 "       cmp             %0, %1\n"
 243 "       bne,pn          %%icc, 1b\n"
 244 "        membar         #StoreLoad | #StoreStore\n"
 245 "       mov             1, %2\n"
 246 "2:"
 247         : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
 248         : "r" (lock), "r" (mask)
 249         : "memory");
 250
 251         return result;
 252 }
 253
 254 #define _raw_read_lock(p)       __read_lock(p)
 255 #define _raw_read_unlock(p)     __read_unlock(p)
 256 #define _raw_write_lock(p)      __write_lock(p)
 257 #define _raw_write_unlock(p)    __write_unlock(p)
 258 #define _raw_write_trylock(p)   __write_trylock(p)
 259
 260 #else /* !(CONFIG_DEBUG_SPINLOCK) */
 261
 262 typedef struct {
 263         volatile unsigned long lock;
 264         unsigned int writer_pc, writer_cpu;
 265         unsigned int reader_pc[NR_CPUS];
 266 #ifdef CONFIG_PREEMPT
 267         unsigned int break_lock;
 268 #endif
 269 } rwlock_t;
 270 #define RW_LOCK_UNLOCKED        (rwlock_t) { 0, 0, 0xff, { } }
 271 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
 272
 273 extern void _do_read_lock(rwlock_t *rw, char *str);
 274 extern void _do_read_unlock(rwlock_t *rw, char *str);
 275 extern void _do_write_lock(rwlock_t *rw, char *str);
 276 extern void _do_write_unlock(rwlock_t *rw);
 277 extern int _do_write_trylock(rwlock_t *rw, char *str);
 278
 279 #define _raw_read_lock(lock) \
 280 do {    unsigned long flags; \
 281         local_irq_save(flags); \
 282         _do_read_lock(lock, "read_lock"); \
 283         local_irq_restore(flags); \
 284 } while(0)
 285
 286 #define _raw_read_unlock(lock) \
 287 do {    unsigned long flags; \
 288         local_irq_save(flags); \
 289         _do_read_unlock(lock, "read_unlock"); \
 290         local_irq_restore(flags); \
 291 } while(0)
 292
 293 #define _raw_write_lock(lock) \
 294 do {    unsigned long flags; \
 295         local_irq_save(flags); \
 296         _do_write_lock(lock, "write_lock"); \
 297         local_irq_restore(flags); \
 298 } while(0)
 299
 300 #define _raw_write_unlock(lock) \
 301 do {    unsigned long flags; \
 302         local_irq_save(flags); \
 303         _do_write_unlock(lock); \
 304         local_irq_restore(flags); \
 305 } while(0)
 306
 307 #define _raw_write_trylock(lock) \
 308 ({      unsigned long flags; \
 309         int val; \
 310         local_irq_save(flags); \
 311         val = _do_write_trylock(lock, "write_trylock"); \
 312         local_irq_restore(flags); \
 313         val; \
 314 })
 315
 316 #endif /* CONFIG_DEBUG_SPINLOCK */
 317
 318 #define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
 319 #define read_can_lock(rw)       (!((rw)->lock & 0x80000000UL))
 320 #define write_can_lock(rw)      (!(rw)->lock)
 321
 322 #endif /* !(__ASSEMBLY__) */
 323
 324 #endif /* !(__SPARC64_SPINLOCK_H) */