lib/librte_eal/common/include/arch/x86/rte_spinlock.h

   1 /*-
   2  *   BSD LICENSE
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  32  */
  33
  34 #ifndef _RTE_SPINLOCK_X86_64_H_
  35 #define _RTE_SPINLOCK_X86_64_H_
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 #include "generic/rte_spinlock.h"
  42 #include "rte_rtm.h"
  43 #include "rte_cpuflags.h"
  44 #include "rte_branch_prediction.h"
  45 #include "rte_common.h"
  46
  47 #define RTE_RTM_MAX_RETRIES (10)
  48 #define RTE_XABORT_LOCK_BUSY (0xff)
  49
  50 #ifndef RTE_FORCE_INTRINSICS
  51 static inline void
  52 rte_spinlock_lock(rte_spinlock_t *sl)
  53 {
  54         int lock_val = 1;
  55         asm volatile (
  56                         "1:\n"
  57                         "xchg %[locked], %[lv]\n"
  58                         "test %[lv], %[lv]\n"
  59                         "jz 3f\n"
  60                         "2:\n"
  61                         "pause\n"
  62                         "cmpl $0, %[locked]\n"
  63                         "jnz 2b\n"
  64                         "jmp 1b\n"
  65                         "3:\n"
  66                         : [locked] "=m" (sl->locked), [lv] "=q" (lock_val)
  67                         : "[lv]" (lock_val)
  68                         : "memory");
  69 }
  70
  71 static inline void
  72 rte_spinlock_unlock (rte_spinlock_t *sl)
  73 {
  74         int unlock_val = 0;
  75         asm volatile (
  76                         "xchg %[locked], %[ulv]\n"
  77                         : [locked] "=m" (sl->locked), [ulv] "=q" (unlock_val)
  78                         : "[ulv]" (unlock_val)
  79                         : "memory");
  80 }
  81
  82 static inline int
  83 rte_spinlock_trylock (rte_spinlock_t *sl)
  84 {
  85         int lockval = 1;
  86
  87         asm volatile (
  88                         "xchg %[locked], %[lockval]"
  89                         : [locked] "=m" (sl->locked), [lockval] "=q" (lockval)
  90                         : "[lockval]" (lockval)
  91                         : "memory");
  92
  93         return lockval == 0;
  94 }
  95 #endif
  96
  97 static uint8_t rtm_supported; /* cache the flag to avoid the overhead
  98                                  of the rte_cpu_get_flag_enabled function */
  99
 100 static inline void __attribute__((constructor))
 101 rte_rtm_init(void)
 102 {
 103         rtm_supported = rte_cpu_get_flag_enabled(RTE_CPUFLAG_RTM);
 104 }
 105
 106 static inline int rte_tm_supported(void)
 107 {
 108         return rtm_supported;
 109 }
 110
 111 static inline int
 112 rte_try_tm(volatile int *lock)
 113 {
 114         if (!rtm_supported)
 115                 return 0;
 116
 117         int retries = RTE_RTM_MAX_RETRIES;
 118
 119         while (likely(retries--)) {
 120
 121                 unsigned int status = rte_xbegin();
 122
 123                 if (likely(RTE_XBEGIN_STARTED == status)) {
 124                         if (unlikely(*lock))
 125                                 rte_xabort(RTE_XABORT_LOCK_BUSY);
 126                         else
 127                                 return 1;
 128                 }
 129                 while (*lock)
 130                         rte_pause();
 131
 132                 if ((status & RTE_XABORT_EXPLICIT) &&
 133                         (RTE_XABORT_CODE(status) == RTE_XABORT_LOCK_BUSY))
 134                         continue;
 135
 136                 if ((status & RTE_XABORT_RETRY) == 0) /* do not retry */
 137                         break;
 138         }
 139         return 0;
 140 }
 141
 142 static inline void
 143 rte_spinlock_lock_tm(rte_spinlock_t *sl)
 144 {
 145         if (likely(rte_try_tm(&sl->locked)))
 146                 return;
 147
 148         rte_spinlock_lock(sl); /* fall-back */
 149 }
 150
 151 static inline int
 152 rte_spinlock_trylock_tm(rte_spinlock_t *sl)
 153 {
 154         if (likely(rte_try_tm(&sl->locked)))
 155                 return 1;
 156
 157         return rte_spinlock_trylock(sl);
 158 }
 159
 160 static inline void
 161 rte_spinlock_unlock_tm(rte_spinlock_t *sl)
 162 {
 163         if (unlikely(sl->locked))
 164                 rte_spinlock_unlock(sl);
 165         else
 166                 rte_xend();
 167 }
 168
 169 static inline void
 170 rte_spinlock_recursive_lock_tm(rte_spinlock_recursive_t *slr)
 171 {
 172         if (likely(rte_try_tm(&slr->sl.locked)))
 173                 return;
 174
 175         rte_spinlock_recursive_lock(slr); /* fall-back */
 176 }
 177
 178 static inline void
 179 rte_spinlock_recursive_unlock_tm(rte_spinlock_recursive_t *slr)
 180 {
 181         if (unlikely(slr->sl.locked))
 182                 rte_spinlock_recursive_unlock(slr);
 183         else
 184                 rte_xend();
 185 }
 186
 187 static inline int
 188 rte_spinlock_recursive_trylock_tm(rte_spinlock_recursive_t *slr)
 189 {
 190         if (likely(rte_try_tm(&slr->sl.locked)))
 191                 return 1;
 192
 193         return rte_spinlock_recursive_trylock(slr);
 194 }
 195
 196
 197 #ifdef __cplusplus
 198 }
 199 #endif
 200
 201 #endif /* _RTE_SPINLOCK_X86_64_H_ */