1 /* Copyright (C) 2005-2022 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 long 34 __futex_wait (int *addr, int futex_op, int val) 35 { 36 long res; 37 38 register void *timeout __asm ("r10") = NULL; 39 __asm volatile ("syscall" 40 : "=a" (res) 41 : "0" (SYS_futex), "D" (addr), "S" (futex_op), 42 "d" (val), "r" (timeout) 43 : "r11", "rcx", "memory"); 44 return res; 45 } 46 47 static inline long 48 __futex_wake (int *addr, int futex_op, int count) 49 { 50 long res; 51 52 __asm volatile ("syscall" 53 : "=a" (res) 54 : "0" (SYS_futex), "D" (addr), "S" (futex_op), 55 "d" (count) 56 : "r11", "rcx", "memory"); 57 return res; 58 } 59 #else 60 # ifndef SYS_futex 61 # define SYS_futex 240 62 # endif 63 64 static inline long 65 __futex_wait (int *addr, int futex_op, int val) 66 { 67 long res; 68 69 void *timeout = NULL; 70 __asm volatile ("int $0x80" 71 : "=a" (res) 72 : "0" (SYS_futex), "b" (addr), "c" (futex_op), 73 "d" (val), "S" (timeout) 74 : "memory"); 75 return res; 76 } 77 78 static inline long 79 __futex_wake (int *addr, int futex_op, int count) 80 { 81 long res; 82 83 __asm volatile ("int $0x80" 84 : "=a" (res) 85 : "0" (SYS_futex), "b" (addr), "c" (futex_op), 86 "d" (count) 87 : "memory"); 88 return res; 89 } 90 #endif /* __x86_64__ */ 91 92 static inline void 93 futex_wait (int *addr, int val) 94 { 95 long err = __futex_wait (addr, gomp_futex_wait, val); 96 97 if (__builtin_expect (err == -ENOSYS, 0)) 98 { 99 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 100 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 101 102 __futex_wait (addr, gomp_futex_wait, val); 103 } 104 } 105 106 static inline void 107 futex_wake (int *addr, int count) 108 { 109 long err = __futex_wake (addr, gomp_futex_wake, count); 110 111 if (__builtin_expect (err == -ENOSYS, 0)) 112 { 113 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 114 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 115 116 __futex_wake (addr, gomp_futex_wake, count); 117 } 118 } 119 120 static inline void 121 cpu_relax (void) 122 { 123 __builtin_ia32_pause (); 124 } 125