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 /* To get debugging spinlocks which detect and catch
  12  * deadlock situations, set CONFIG_DEBUG_SPINLOCK
  13  * and rebuild your kernel.
  14  */
  15
  16 /* Because we play games to save cycles in the non-contention case, we
  17  * need to be extra careful about branch targets into the "spinning"
  18  * code.  They live in their own section, but the newer V9 branches
  19  * have a shorter range than the traditional 32-bit sparc branch
  20  * variants.  The rule is that the branches that go into and out of
  21  * the spinner sections must be pre-V9 branches.
  22  */
  23
  24 #define arch_spin_is_locked(lp) ((lp)->lock != 0)
  25
  26 #define arch_spin_unlock_wait(lp)       \
  27         do {    rmb();                  \
  28         } while((lp)->lock)
  29
  30 static inline void arch_spin_lock(arch_spinlock_t *lock)
  31 {
  32         unsigned long tmp;
  33
  34         __asm__ __volatile__(
  35 "1:     ldstub          [%1], %0\n"
  36 "       brnz,pn         %0, 2f\n"
  37 "        nop\n"
  38 "       .subsection     2\n"
  39 "2:     ldub            [%1], %0\n"
  40 "       brnz,pt         %0, 2b\n"
  41 "        nop\n"
  42 "       ba,a,pt         %%xcc, 1b\n"
  43 "       .previous"
  44         : "=&r" (tmp)
  45         : "r" (lock)
  46         : "memory");
  47 }
  48
  49 static inline int arch_spin_trylock(arch_spinlock_t *lock)
  50 {
  51         unsigned long result;
  52
  53         __asm__ __volatile__(
  54 "       ldstub          [%1], %0\n"
  55         : "=r" (result)
  56         : "r" (lock)
  57         : "memory");
  58
  59         return (result == 0UL);
  60 }
  61
  62 static inline void arch_spin_unlock(arch_spinlock_t *lock)
  63 {
  64         __asm__ __volatile__(
  65 "       stb             %%g0, [%0]"
  66         : /* No outputs */
  67         : "r" (lock)
  68         : "memory");
  69 }
  70
  71 static inline void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
  72 {
  73         unsigned long tmp1, tmp2;
  74
  75         __asm__ __volatile__(
  76 "1:     ldstub          [%2], %0\n"
  77 "       brnz,pn         %0, 2f\n"
  78 "        nop\n"
  79 "       .subsection     2\n"
  80 "2:     rdpr            %%pil, %1\n"
  81 "       wrpr            %3, %%pil\n"
  82 "3:     ldub            [%2], %0\n"
  83 "       brnz,pt         %0, 3b\n"
  84 "        nop\n"
  85 "       ba,pt           %%xcc, 1b\n"
  86 "        wrpr           %1, %%pil\n"
  87 "       .previous"
  88         : "=&r" (tmp1), "=&r" (tmp2)
  89         : "r"(lock), "r"(flags)
  90         : "memory");
  91 }
  92
  93 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
  94
  95 static void inline arch_read_lock(arch_rwlock_t *lock)
  96 {
  97         unsigned long tmp1, tmp2;
  98
  99         __asm__ __volatile__ (
 100 "1:     ldsw            [%2], %0\n"
 101 "       brlz,pn         %0, 2f\n"
 102 "4:      add            %0, 1, %1\n"
 103 "       cas             [%2], %0, %1\n"
 104 "       cmp             %0, %1\n"
 105 "       bne,pn          %%icc, 1b\n"
 106 "        nop\n"
 107 "       .subsection     2\n"
 108 "2:     ldsw            [%2], %0\n"
 109 "       brlz,pt         %0, 2b\n"
 110 "        nop\n"
 111 "       ba,a,pt         %%xcc, 4b\n"
 112 "       .previous"
 113         : "=&r" (tmp1), "=&r" (tmp2)
 114         : "r" (lock)
 115         : "memory");
 116 }
 117
 118 static int inline arch_read_trylock(arch_rwlock_t *lock)
 119 {
 120         int tmp1, tmp2;
 121
 122         __asm__ __volatile__ (
 123 "1:     ldsw            [%2], %0\n"
 124 "       brlz,a,pn       %0, 2f\n"
 125 "        mov            0, %0\n"
 126 "       add             %0, 1, %1\n"
 127 "       cas             [%2], %0, %1\n"
 128 "       cmp             %0, %1\n"
 129 "       bne,pn          %%icc, 1b\n"
 130 "        mov            1, %0\n"
 131 "2:"
 132         : "=&r" (tmp1), "=&r" (tmp2)
 133         : "r" (lock)
 134         : "memory");
 135
 136         return tmp1;
 137 }
 138
 139 static void inline arch_read_unlock(arch_rwlock_t *lock)
 140 {
 141         unsigned long tmp1, tmp2;
 142
 143         __asm__ __volatile__(
 144 "1:     lduw    [%2], %0\n"
 145 "       sub     %0, 1, %1\n"
 146 "       cas     [%2], %0, %1\n"
 147 "       cmp     %0, %1\n"
 148 "       bne,pn  %%xcc, 1b\n"
 149 "        nop"
 150         : "=&r" (tmp1), "=&r" (tmp2)
 151         : "r" (lock)
 152         : "memory");
 153 }
 154
 155 static void inline arch_write_lock(arch_rwlock_t *lock)
 156 {
 157         unsigned long mask, tmp1, tmp2;
 158
 159         mask = 0x80000000UL;
 160
 161         __asm__ __volatile__(
 162 "1:     lduw            [%2], %0\n"
 163 "       brnz,pn         %0, 2f\n"
 164 "4:      or             %0, %3, %1\n"
 165 "       cas             [%2], %0, %1\n"
 166 "       cmp             %0, %1\n"
 167 "       bne,pn          %%icc, 1b\n"
 168 "        nop\n"
 169 "       .subsection     2\n"
 170 "2:     lduw            [%2], %0\n"
 171 "       brnz,pt         %0, 2b\n"
 172 "        nop\n"
 173 "       ba,a,pt         %%xcc, 4b\n"
 174 "       .previous"
 175         : "=&r" (tmp1), "=&r" (tmp2)
 176         : "r" (lock), "r" (mask)
 177         : "memory");
 178 }
 179
 180 static void inline arch_write_unlock(arch_rwlock_t *lock)
 181 {
 182         __asm__ __volatile__(
 183 "       stw             %%g0, [%0]"
 184         : /* no outputs */
 185         : "r" (lock)
 186         : "memory");
 187 }
 188
 189 static int inline arch_write_trylock(arch_rwlock_t *lock)
 190 {
 191         unsigned long mask, tmp1, tmp2, result;
 192
 193         mask = 0x80000000UL;
 194
 195         __asm__ __volatile__(
 196 "       mov             0, %2\n"
 197 "1:     lduw            [%3], %0\n"
 198 "       brnz,pn         %0, 2f\n"
 199 "        or             %0, %4, %1\n"
 200 "       cas             [%3], %0, %1\n"
 201 "       cmp             %0, %1\n"
 202 "       bne,pn          %%icc, 1b\n"
 203 "        nop\n"
 204 "       mov             1, %2\n"
 205 "2:"
 206         : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
 207         : "r" (lock), "r" (mask)
 208         : "memory");
 209
 210         return result;
 211 }
 212
 213 #define arch_read_lock_flags(p, f) arch_read_lock(p)
 214 #define arch_write_lock_flags(p, f) arch_write_lock(p)
 215
 216 #define arch_read_can_lock(rw)          (!((rw)->lock & 0x80000000UL))
 217 #define arch_write_can_lock(rw) (!(rw)->lock)
 218
 219 #define arch_spin_relax(lock)   cpu_relax()
 220 #define arch_read_relax(lock)   cpu_relax()
 221 #define arch_write_relax(lock)  cpu_relax()
 222
 223 #endif /* !(__ASSEMBLY__) */
 224
 225 #endif /* !(__SPARC64_SPINLOCK_H) */