libitm/config/powerpc/target.h

   1 /* Copyright (C) 2012-2020 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <rth@redhat.com>.
   3
   4    This file is part of the GNU Transactional Memory Library (libitm).
   5
   6    Libitm is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
  12    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14    more details.
  15
  16    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 #ifdef HAVE_SYS_AUXV_H
  26 #include <sys/auxv.h>
  27 #endif
  28
  29 namespace GTM HIDDEN {
  30
  31 typedef int v128 __attribute__((vector_size(16), may_alias, aligned(16)));
  32 typedef struct gtm_jmpbuf
  33 {
  34 #if defined(__ALTIVEC__) || defined(__VSX__)
  35   v128 vr[12];                  /* vr20-vr31 */
  36   unsigned long long vscr;      /* long long for padding only */
  37 #endif
  38 #ifndef _SOFT_FLOAT
  39   double fr[18];                /* f14-f31 */
  40   double fpscr;
  41 #endif
  42   unsigned long gr[18];         /* r14-r31 */
  43   void *cfa;
  44   unsigned long pc;
  45   unsigned long toc;            /* r2 on aix, r13 on darwin */
  46   unsigned long cr;
  47 } gtm_jmpbuf;
  48
  49 /* The size of one line in hardware caches (in bytes). */
  50 #if defined (__powerpc64__) || defined (__ppc64__)
  51 # define HW_CACHELINE_SIZE 128
  52 #else
  53 # define HW_CACHELINE_SIZE 32
  54 #endif
  55
  56 static inline void
  57 cpu_relax (void)
  58 {
  59   __asm volatile ("" : : : "memory");
  60 }
  61
  62 // Use HTM if it is supported by the system.
  63 // See gtm_thread::begin_transaction for how these functions are used.
  64 #if defined (__linux__) \
  65     && defined (HAVE_AS_HTM) \
  66     && defined (HAVE_GETAUXVAL) \
  67     && defined (AT_HWCAP2) \
  68     && defined (PPC_FEATURE2_HAS_HTM)
  69
  70 #include <htmintrin.h>
  71
  72 #define USE_HTM_FASTPATH
  73
  74 #define _TBEGIN_STARTED       0
  75 #define _TBEGIN_INDETERMINATE 1
  76 #define _TBEGIN_PERSISTENT    2
  77
  78 /* Number of retries for transient failures.  */
  79 #define _HTM_RETRIES 10
  80
  81 static inline bool
  82 htm_available (void)
  83 {
  84 #ifdef __BUILTIN_CPU_SUPPORTS__
  85   if (__builtin_cpu_supports ("htm-no-suspend")
  86       || __builtin_cpu_supports ("htm"))
  87     return true;
  88 #else
  89   unsigned long htm_flags = PPC_FEATURE2_HAS_HTM
  90 #ifdef PPC_FEATURE2_HTM_NO_SUSPEND
  91                             | PPC_FEATURE2_HTM_NO_SUSPEND
  92 #endif
  93                             | 0;
  94   if (getauxval (AT_HWCAP2) & htm_flags)
  95     return true;
  96 #endif
  97   return false;
  98 }
  99
 100 static inline uint32_t
 101 htm_init (void)
 102 {
 103   // Maximum number of times we try to execute a transaction
 104   // as a HW transaction.
 105   return htm_available () ? _HTM_RETRIES : 0;
 106 }
 107
 108 static inline uint32_t
 109 htm_begin (void)
 110 {
 111   if (__builtin_expect (__builtin_tbegin (0), 1))
 112     return _TBEGIN_STARTED;
 113
 114   if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
 115     return _TBEGIN_PERSISTENT;
 116
 117   return _TBEGIN_INDETERMINATE;
 118 }
 119
 120 static inline bool
 121 htm_begin_success (uint32_t begin_ret)
 122 {
 123   return begin_ret == _TBEGIN_STARTED;
 124 }
 125
 126 static inline void
 127 htm_commit (void)
 128 {
 129   __builtin_tend (0);
 130 }
 131
 132 static inline void
 133 htm_abort (void)
 134 {
 135   __builtin_tabort (0);
 136 }
 137
 138 static inline bool
 139 htm_abort_should_retry (uint32_t begin_ret)
 140 {
 141   return begin_ret != _TBEGIN_PERSISTENT;
 142 }
 143
 144 /* Returns true iff a hardware transaction is currently being executed.  */
 145 static inline bool
 146 htm_transaction_active (void)
 147 {
 148   return (_HTM_STATE (__builtin_ttest ()) == _HTM_TRANSACTIONAL);
 149 }
 150
 151 #endif
 152
 153 } // namespace GTM