futex.h revision 1.1.1.2
1/* Copyright (C) 2005-2013 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU OpenMP Library (libgomp). 5 6 Libgomp 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, or (at your option) 9 any later version. 10 11 Libgomp 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/* Provide target-specific access to the futex system call. */ 26 27#include <sys/syscall.h> 28 29 30 31static inline long 32sys_futex0(int *addr, long op, int val) 33{ 34 register long out0 asm ("out0") = (long) addr; 35 register long out1 asm ("out1") = op; 36 register long out2 asm ("out2") = val; 37 register long out3 asm ("out3") = 0; 38 register long r8 asm ("r8"); 39 register long r10 asm ("r10"); 40 register long r15 asm ("r15") = SYS_futex; 41 42 __asm __volatile ("break 0x100000" 43 : "=r"(r15), "=r"(out0), "=r"(out1), "=r"(out2), "=r"(out3), 44 "=r"(r8), "=r"(r10) 45 : "r"(r15), "r"(out0), "r"(out1), "r"(out2), "r"(out3) 46 : "memory", "out4", "out5", "out6", "out7", 47 /* Non-stacked integer registers, minus r8, r10, r15. */ 48 "r2", "r3", "r9", "r11", "r12", "r13", "r14", "r16", "r17", "r18", 49 "r19", "r20", "r21", "r22", "r23", "r24", "r25", "r26", "r27", 50 "r28", "r29", "r30", "r31", 51 /* Predicate registers. */ 52 "p6", "p7", "p8", "p9", "p10", "p11", "p12", "p13", "p14", "p15", 53 /* Non-rotating fp registers. */ 54 "f6", "f7", "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", 55 /* Branch registers. */ 56 "b6"); 57 return r8 & r10; 58} 59 60static inline void 61futex_wait (int *addr, int val) 62{ 63 long err = sys_futex0 (addr, gomp_futex_wait, val); 64 if (__builtin_expect (err == ENOSYS, 0)) 65 { 66 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 67 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 68 sys_futex0 (addr, gomp_futex_wait, val); 69 } 70} 71 72static inline void 73futex_wake (int *addr, int count) 74{ 75 long err = sys_futex0 (addr, gomp_futex_wake, count); 76 if (__builtin_expect (err == ENOSYS, 0)) 77 { 78 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 79 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 80 sys_futex0 (addr, gomp_futex_wake, count); 81 } 82} 83 84static inline void 85cpu_relax (void) 86{ 87 __asm volatile ("hint @pause" : : : "memory"); 88} 89