arch/sparc/include/asm/spinlock_64.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 #ifndef __ASSEMBLY__
  10
  11 #include <asm/processor.h>
  12 #include <asm/barrier.h>
  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 /* Because we play games to save cycles in the non-contention case, we
  20  * need to be extra careful about branch targets into the "spinning"
  21  * code.  They live in their own section, but the newer V9 branches
  22  * have a shorter range than the traditional 32-bit sparc branch
  23  * variants.  The rule is that the branches that go into and out of
  24  * the spinner sections must be pre-V9 branches.
  25  */
  26
  27 #define arch_spin_is_locked(lp) ((lp)->lock != 0)
  28
  29 static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
  30 {
  31         smp_cond_load_acquire(&lock->lock, !VAL);
  32 }
  33
  34 static inline void arch_spin_lock(arch_spinlock_t *lock)
  35 {
  36         unsigned long tmp;
  37
  38         __asm__ __volatile__(
  39 "1:     ldstub          [%1], %0\n"
  40 "       brnz,pn         %0, 2f\n"
  41 "        nop\n"
  42 "       .subsection     2\n"
  43 "2:     ldub            [%1], %0\n"
  44 "       brnz,pt         %0, 2b\n"
  45 "        nop\n"
  46 "       ba,a,pt         %%xcc, 1b\n"
  47 "       .previous"
  48         : "=&r" (tmp)
  49         : "r" (lock)
  50         : "memory");
  51 }
  52
  53 static inline int arch_spin_trylock(arch_spinlock_t *lock)
  54 {
  55         unsigned long result;
  56
  57         __asm__ __volatile__(
  58 "       ldstub          [%1], %0\n"
  59         : "=r" (result)
  60         : "r" (lock)
  61         : "memory");
  62
  63         return (result == 0UL);
  64 }
  65
  66 static inline void arch_spin_unlock(arch_spinlock_t *lock)
  67 {
  68         __asm__ __volatile__(
  69 "       stb             %%g0, [%0]"
  70         : /* No outputs */
  71         : "r" (lock)
  72         : "memory");
  73 }
  74
  75 static inline void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
  76 {
  77         unsigned long tmp1, tmp2;
  78
  79         __asm__ __volatile__(
  80 "1:     ldstub          [%2], %0\n"
  81 "       brnz,pn         %0, 2f\n"
  82 "        nop\n"
  83 "       .subsection     2\n"
  84 "2:     rdpr            %%pil, %1\n"
  85 "       wrpr            %3, %%pil\n"
  86 "3:     ldub            [%2], %0\n"
  87 "       brnz,pt         %0, 3b\n"
  88 "        nop\n"
  89 "       ba,pt           %%xcc, 1b\n"
  90 "        wrpr           %1, %%pil\n"
  91 "       .previous"
  92         : "=&r" (tmp1), "=&r" (tmp2)
  93         : "r"(lock), "r"(flags)
  94         : "memory");
  95 }
  96
  97 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
  98
  99 static void inline arch_read_lock(arch_rwlock_t *lock)
 100 {
 101         unsigned long tmp1, tmp2;
 102
 103         __asm__ __volatile__ (
 104 "1:     ldsw            [%2], %0\n"
 105 "       brlz,pn         %0, 2f\n"
 106 "4:      add            %0, 1, %1\n"
 107 "       cas             [%2], %0, %1\n"
 108 "       cmp             %0, %1\n"
 109 "       bne,pn          %%icc, 1b\n"
 110 "        nop\n"
 111 "       .subsection     2\n"
 112 "2:     ldsw            [%2], %0\n"
 113 "       brlz,pt         %0, 2b\n"
 114 "        nop\n"
 115 "       ba,a,pt         %%xcc, 4b\n"
 116 "       .previous"
 117         : "=&r" (tmp1), "=&r" (tmp2)
 118         : "r" (lock)
 119         : "memory");
 120 }
 121
 122 static int inline arch_read_trylock(arch_rwlock_t *lock)
 123 {
 124         int tmp1, tmp2;
 125
 126         __asm__ __volatile__ (
 127 "1:     ldsw            [%2], %0\n"
 128 "       brlz,a,pn       %0, 2f\n"
 129 "        mov            0, %0\n"
 130 "       add             %0, 1, %1\n"
 131 "       cas             [%2], %0, %1\n"
 132 "       cmp             %0, %1\n"
 133 "       bne,pn          %%icc, 1b\n"
 134 "        mov            1, %0\n"
 135 "2:"
 136         : "=&r" (tmp1), "=&r" (tmp2)
 137         : "r" (lock)
 138         : "memory");
 139
 140         return tmp1;
 141 }
 142
 143 static void inline arch_read_unlock(arch_rwlock_t *lock)
 144 {
 145         unsigned long tmp1, tmp2;
 146
 147         __asm__ __volatile__(
 148 "1:     lduw    [%2], %0\n"
 149 "       sub     %0, 1, %1\n"
 150 "       cas     [%2], %0, %1\n"
 151 "       cmp     %0, %1\n"
 152 "       bne,pn  %%xcc, 1b\n"
 153 "        nop"
 154         : "=&r" (tmp1), "=&r" (tmp2)
 155         : "r" (lock)
 156         : "memory");
 157 }
 158
 159 static void inline arch_write_lock(arch_rwlock_t *lock)
 160 {
 161         unsigned long mask, tmp1, tmp2;
 162
 163         mask = 0x80000000UL;
 164
 165         __asm__ __volatile__(
 166 "1:     lduw            [%2], %0\n"
 167 "       brnz,pn         %0, 2f\n"
 168 "4:      or             %0, %3, %1\n"
 169 "       cas             [%2], %0, %1\n"
 170 "       cmp             %0, %1\n"
 171 "       bne,pn          %%icc, 1b\n"
 172 "        nop\n"
 173 "       .subsection     2\n"
 174 "2:     lduw            [%2], %0\n"
 175 "       brnz,pt         %0, 2b\n"
 176 "        nop\n"
 177 "       ba,a,pt         %%xcc, 4b\n"
 178 "       .previous"
 179         : "=&r" (tmp1), "=&r" (tmp2)
 180         : "r" (lock), "r" (mask)
 181         : "memory");
 182 }
 183
 184 static void inline arch_write_unlock(arch_rwlock_t *lock)
 185 {
 186         __asm__ __volatile__(
 187 "       stw             %%g0, [%0]"
 188         : /* no outputs */
 189         : "r" (lock)
 190         : "memory");
 191 }
 192
 193 static int inline arch_write_trylock(arch_rwlock_t *lock)
 194 {
 195         unsigned long mask, tmp1, tmp2, result;
 196
 197         mask = 0x80000000UL;
 198
 199         __asm__ __volatile__(
 200 "       mov             0, %2\n"
 201 "1:     lduw            [%3], %0\n"
 202 "       brnz,pn         %0, 2f\n"
 203 "        or             %0, %4, %1\n"
 204 "       cas             [%3], %0, %1\n"
 205 "       cmp             %0, %1\n"
 206 "       bne,pn          %%icc, 1b\n"
 207 "        nop\n"
 208 "       mov             1, %2\n"
 209 "2:"
 210         : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
 211         : "r" (lock), "r" (mask)
 212         : "memory");
 213
 214         return result;
 215 }
 216
 217 #define arch_read_lock_flags(p, f) arch_read_lock(p)
 218 #define arch_write_lock_flags(p, f) arch_write_lock(p)
 219
 220 #define arch_read_can_lock(rw)          (!((rw)->lock & 0x80000000UL))
 221 #define arch_write_can_lock(rw) (!(rw)->lock)
 222
 223 #define arch_spin_relax(lock)   cpu_relax()
 224 #define arch_read_relax(lock)   cpu_relax()
 225 #define arch_write_relax(lock)  cpu_relax()
 226
 227 #endif /* !(__ASSEMBLY__) */
 228
 229 #endif /* !(__SPARC64_SPINLOCK_H) */