include/asm-ia64/spinlock.h

   1 #ifndef _ASM_IA64_SPINLOCK_H
   2 #define _ASM_IA64_SPINLOCK_H
   3
   4 /*
   5  * Copyright (C) 1998-2003 Hewlett-Packard Co
   6  *      David Mosberger-Tang <davidm@hpl.hp.com>
   7  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
   8  *
   9  * This file is used for SMP configurations only.
  10  */
  11
  12 #include <linux/compiler.h>
  13 #include <linux/kernel.h>
  14
  15 #include <asm/atomic.h>
  16 #include <asm/bitops.h>
  17 #include <asm/intrinsics.h>
  18 #include <asm/system.h>
  19
  20 #define __raw_spin_lock_init(x)                 ((x)->lock = 0)
  21
  22 #ifdef ASM_SUPPORTED
  23 /*
  24  * Try to get the lock.  If we fail to get the lock, make a non-standard call to
  25  * ia64_spinlock_contention().  We do not use a normal call because that would force all
  26  * callers of __raw_spin_lock() to be non-leaf routines.  Instead, ia64_spinlock_contention() is
  27  * carefully coded to touch only those registers that __raw_spin_lock() marks "clobbered".
  28  */
  29
  30 #define IA64_SPINLOCK_CLOBBERS "ar.ccv", "ar.pfs", "p14", "p15", "r27", "r28", "r29", "r30", "b6", "memory"
  31
  32 static inline void
  33 __raw_spin_lock_flags (raw_spinlock_t *lock, unsigned long flags)
  34 {
  35         register volatile unsigned int *ptr asm ("r31") = &lock->lock;
  36
  37 #if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
  38 # ifdef CONFIG_ITANIUM
  39         /* don't use brl on Itanium... */
  40         asm volatile ("{\n\t"
  41                       "  mov ar.ccv = r0\n\t"
  42                       "  mov r28 = ip\n\t"
  43                       "  mov r30 = 1;;\n\t"
  44                       "}\n\t"
  45                       "cmpxchg4.acq r30 = [%1], r30, ar.ccv\n\t"
  46                       "movl r29 = ia64_spinlock_contention_pre3_4;;\n\t"
  47                       "cmp4.ne p14, p0 = r30, r0\n\t"
  48                       "mov b6 = r29;;\n\t"
  49                       "mov r27=%2\n\t"
  50                       "(p14) br.cond.spnt.many b6"
  51                       : "=r"(ptr) : "r"(ptr), "r" (flags) : IA64_SPINLOCK_CLOBBERS);
  52 # else
  53         asm volatile ("{\n\t"
  54                       "  mov ar.ccv = r0\n\t"
  55                       "  mov r28 = ip\n\t"
  56                       "  mov r30 = 1;;\n\t"
  57                       "}\n\t"
  58                       "cmpxchg4.acq r30 = [%1], r30, ar.ccv;;\n\t"
  59                       "cmp4.ne p14, p0 = r30, r0\n\t"
  60                       "mov r27=%2\n\t"
  61                       "(p14) brl.cond.spnt.many ia64_spinlock_contention_pre3_4;;"
  62                       : "=r"(ptr) : "r"(ptr), "r" (flags) : IA64_SPINLOCK_CLOBBERS);
  63 # endif /* CONFIG_MCKINLEY */
  64 #else
  65 # ifdef CONFIG_ITANIUM
  66         /* don't use brl on Itanium... */
  67         /* mis-declare, so we get the entry-point, not it's function descriptor: */
  68         asm volatile ("mov r30 = 1\n\t"
  69                       "mov r27=%2\n\t"
  70                       "mov ar.ccv = r0;;\n\t"
  71                       "cmpxchg4.acq r30 = [%0], r30, ar.ccv\n\t"
  72                       "movl r29 = ia64_spinlock_contention;;\n\t"
  73                       "cmp4.ne p14, p0 = r30, r0\n\t"
  74                       "mov b6 = r29;;\n\t"
  75                       "(p14) br.call.spnt.many b6 = b6"
  76                       : "=r"(ptr) : "r"(ptr), "r" (flags) : IA64_SPINLOCK_CLOBBERS);
  77 # else
  78         asm volatile ("mov r30 = 1\n\t"
  79                       "mov r27=%2\n\t"
  80                       "mov ar.ccv = r0;;\n\t"
  81                       "cmpxchg4.acq r30 = [%0], r30, ar.ccv;;\n\t"
  82                       "cmp4.ne p14, p0 = r30, r0\n\t"
  83                       "(p14) brl.call.spnt.many b6=ia64_spinlock_contention;;"
  84                       : "=r"(ptr) : "r"(ptr), "r" (flags) : IA64_SPINLOCK_CLOBBERS);
  85 # endif /* CONFIG_MCKINLEY */
  86 #endif
  87 }
  88
  89 #define __raw_spin_lock(lock) __raw_spin_lock_flags(lock, 0)
  90
  91 /* Unlock by doing an ordered store and releasing the cacheline with nta */
  92 static inline void __raw_spin_unlock(raw_spinlock_t *x) {
  93         barrier();
  94         asm volatile ("st4.rel.nta [%0] = r0\n\t" :: "r"(x));
  95 }
  96
  97 #else /* !ASM_SUPPORTED */
  98 #define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
  99 # define __raw_spin_lock(x)                                                             \
 100 do {                                                                                    \
 101         __u32 *ia64_spinlock_ptr = (__u32 *) (x);                                       \
 102         __u64 ia64_spinlock_val;                                                        \
 103         ia64_spinlock_val = ia64_cmpxchg4_acq(ia64_spinlock_ptr, 1, 0);                 \
 104         if (unlikely(ia64_spinlock_val)) {                                              \
 105                 do {                                                                    \
 106                         while (*ia64_spinlock_ptr)                                      \
 107                                 ia64_barrier();                                         \
 108                         ia64_spinlock_val = ia64_cmpxchg4_acq(ia64_spinlock_ptr, 1, 0); \
 109                 } while (ia64_spinlock_val);                                            \
 110         }                                                                               \
 111 } while (0)
 112 #define __raw_spin_unlock(x)    do { barrier(); ((raw_spinlock_t *) x)->lock = 0; } while (0)
 113 #endif /* !ASM_SUPPORTED */
 114
 115 #define __raw_spin_is_locked(x)         ((x)->lock != 0)
 116 #define __raw_spin_trylock(x)           (cmpxchg_acq(&(x)->lock, 0, 1) == 0)
 117 #define __raw_spin_unlock_wait(lock) \
 118         do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
 119
 120 #define __raw_read_can_lock(rw)         (*(volatile int *)(rw) >= 0)
 121 #define __raw_write_can_lock(rw)        (*(volatile int *)(rw) == 0)
 122
 123 #define __raw_read_lock(rw)                                                             \
 124 do {                                                                                    \
 125         raw_rwlock_t *__read_lock_ptr = (rw);                                           \
 126                                                                                         \
 127         while (unlikely(ia64_fetchadd(1, (int *) __read_lock_ptr, acq) < 0)) {          \
 128                 ia64_fetchadd(-1, (int *) __read_lock_ptr, rel);                        \
 129                 while (*(volatile int *)__read_lock_ptr < 0)                            \
 130                         cpu_relax();                                                    \
 131         }                                                                               \
 132 } while (0)
 133
 134 #define __raw_read_unlock(rw)                                   \
 135 do {                                                            \
 136         raw_rwlock_t *__read_lock_ptr = (rw);                   \
 137         ia64_fetchadd(-1, (int *) __read_lock_ptr, rel);        \
 138 } while (0)
 139
 140 #ifdef ASM_SUPPORTED
 141 #define __raw_write_lock(rw)                                                    \
 142 do {                                                                            \
 143         __asm__ __volatile__ (                                                  \
 144                 "mov ar.ccv = r0\n"                                             \
 145                 "dep r29 = -1, r0, 31, 1;;\n"                                   \
 146                 "1:\n"                                                          \
 147                 "ld4 r2 = [%0];;\n"                                             \
 148                 "cmp4.eq p0,p7 = r0,r2\n"                                       \
 149                 "(p7) br.cond.spnt.few 1b \n"                                   \
 150                 "cmpxchg4.acq r2 = [%0], r29, ar.ccv;;\n"                       \
 151                 "cmp4.eq p0,p7 = r0, r2\n"                                      \
 152                 "(p7) br.cond.spnt.few 1b;;\n"                                  \
 153                 :: "r"(rw) : "ar.ccv", "p7", "r2", "r29", "memory");            \
 154 } while(0)
 155
 156 #define __raw_write_trylock(rw)                                                 \
 157 ({                                                                              \
 158         register long result;                                                   \
 159                                                                                 \
 160         __asm__ __volatile__ (                                                  \
 161                 "mov ar.ccv = r0\n"                                             \
 162                 "dep r29 = -1, r0, 31, 1;;\n"                                   \
 163                 "cmpxchg4.acq %0 = [%1], r29, ar.ccv\n"                         \
 164                 : "=r"(result) : "r"(rw) : "ar.ccv", "r29", "memory");          \
 165         (result == 0);                                                          \
 166 })
 167
 168 static inline void __raw_write_unlock(raw_rwlock_t *x)
 169 {
 170         u8 *y = (u8 *)x;
 171         barrier();
 172         asm volatile ("st1.rel.nta [%0] = r0\n\t" :: "r"(y+3) : "memory" );
 173 }
 174
 175 #else /* !ASM_SUPPORTED */
 176
 177 #define __raw_write_lock(l)                                                             \
 178 ({                                                                                      \
 179         __u64 ia64_val, ia64_set_val = ia64_dep_mi(-1, 0, 31, 1);                       \
 180         __u32 *ia64_write_lock_ptr = (__u32 *) (l);                                     \
 181         do {                                                                            \
 182                 while (*ia64_write_lock_ptr)                                            \
 183                         ia64_barrier();                                                 \
 184                 ia64_val = ia64_cmpxchg4_acq(ia64_write_lock_ptr, ia64_set_val, 0);     \
 185         } while (ia64_val);                                                             \
 186 })
 187
 188 #define __raw_write_trylock(rw)                                         \
 189 ({                                                                      \
 190         __u64 ia64_val;                                                 \
 191         __u64 ia64_set_val = ia64_dep_mi(-1, 0, 31,1);                  \
 192         ia64_val = ia64_cmpxchg4_acq((__u32 *)(rw), ia64_set_val, 0);   \
 193         (ia64_val == 0);                                                \
 194 })
 195
 196 static inline void __raw_write_unlock(raw_rwlock_t *x)
 197 {
 198         barrier();
 199         x->write_lock = 0;
 200 }
 201
 202 #endif /* !ASM_SUPPORTED */
 203
 204 static inline int __raw_read_trylock(raw_rwlock_t *x)
 205 {
 206         union {
 207                 raw_rwlock_t lock;
 208                 __u32 word;
 209         } old, new;
 210         old.lock = new.lock = *x;
 211         old.lock.write_lock = new.lock.write_lock = 0;
 212         ++new.lock.read_counter;
 213         return (u32)ia64_cmpxchg4_acq((__u32 *)(x), new.word, old.word) == old.word;
 214 }
 215
 216 #endif /*  _ASM_IA64_SPINLOCK_H */