1 /* Copyright (C) 2005-2015 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU Offloading and Multi Processing Library 5 (libgomp). 6 7 Libgomp is free software; you can redistribute it and/or modify it 8 under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3, or (at your option) 10 any later version. 11 12 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 14 FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15 more details. 16 17 Under Section 7 of GPL version 3, you are granted additional 18 permissions described in the GCC Runtime Library Exception, version 19 3.1, as published by the Free Software Foundation. 20 21 You should have received a copy of the GNU General Public License and 22 a copy of the GCC Runtime Library Exception along with this program; 23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 <http://www.gnu.org/licenses/>. */ 25 26 /* Provide target-specific access to the futex system call. */ 27 28 #ifdef __x86_64__ 29 # ifndef SYS_futex 30 # define SYS_futex 202 31 # endif 32 33 static inline void 34 futex_wait (int *addr, int val) 35 { 36 register long r10 __asm__("%r10"); 37 long res; 38 39 r10 = 0; 40 __asm volatile ("syscall" 41 : "=a" (res) 42 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wait), 43 "d" (val), "r" (r10) 44 : "r11", "rcx", "memory"); 45 if (__builtin_expect (res == -ENOSYS, 0)) 46 { 47 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 48 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 49 r10 = 0; 50 __asm volatile ("syscall" 51 : "=a" (res) 52 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wait), 53 "d" (val), "r" (r10) 54 : "r11", "rcx", "memory"); 55 } 56 } 57 58 static inline void 59 futex_wake (int *addr, int count) 60 { 61 long res; 62 63 __asm volatile ("syscall" 64 : "=a" (res) 65 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wake), 66 "d" (count) 67 : "r11", "rcx", "memory"); 68 if (__builtin_expect (res == -ENOSYS, 0)) 69 { 70 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 71 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 72 __asm volatile ("syscall" 73 : "=a" (res) 74 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wake), 75 "d" (count) 76 : "r11", "rcx", "memory"); 77 } 78 } 79 #else 80 # ifndef SYS_futex 81 # define SYS_futex 240 82 # endif 83 84 # ifdef __PIC__ 85 86 static inline long 87 sys_futex0 (int *addr, int op, int val) 88 { 89 long res; 90 91 __asm volatile ("xchgl\t%%ebx, %2\n\t" 92 "int\t$0x80\n\t" 93 "xchgl\t%%ebx, %2" 94 : "=a" (res) 95 : "0"(SYS_futex), "r" (addr), "c"(op), 96 "d"(val), "S"(0) 97 : "memory"); 98 return res; 99 } 100 101 # else 102 103 static inline long 104 sys_futex0 (int *addr, int op, int val) 105 { 106 long res; 107 108 __asm volatile ("int $0x80" 109 : "=a" (res) 110 : "0"(SYS_futex), "b" (addr), "c"(op), 111 "d"(val), "S"(0) 112 : "memory"); 113 return res; 114 } 115 116 # endif /* __PIC__ */ 117 118 static inline void 119 futex_wait (int *addr, int val) 120 { 121 long res = sys_futex0 (addr, gomp_futex_wait, val); 122 if (__builtin_expect (res == -ENOSYS, 0)) 123 { 124 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 125 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 126 sys_futex0 (addr, gomp_futex_wait, val); 127 } 128 } 129 130 static inline void 131 futex_wake (int *addr, int count) 132 { 133 long res = sys_futex0 (addr, gomp_futex_wake, count); 134 if (__builtin_expect (res == -ENOSYS, 0)) 135 { 136 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 137 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 138 sys_futex0 (addr, gomp_futex_wake, count); 139 } 140 } 141 142 #endif /* __x86_64__ */ 143 144 static inline void 145 cpu_relax (void) 146 { 147 __builtin_ia32_pause (); 148 } 149