1 /* Copyright (C) 2005, 2008, 2009 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 static inline long 30 sys_futex0 (int *addr, int op, int val) 31 { 32 register long int r0 __asm__ ("r0"); 33 register long int r3 __asm__ ("r3"); 34 register long int r4 __asm__ ("r4"); 35 register long int r5 __asm__ ("r5"); 36 register long int r6 __asm__ ("r6"); 37 38 r0 = SYS_futex; 39 r3 = (long) addr; 40 r4 = op; 41 r5 = val; 42 r6 = 0; 43 44 /* ??? The powerpc64 sysdep.h file clobbers ctr; the powerpc32 sysdep.h 45 doesn't. It doesn't much matter for us. In the interest of unity, 46 go ahead and clobber it always. */ 47 48 __asm volatile ("sc; mfcr %0" 49 : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6) 50 : "r"(r0), "r"(r3), "r"(r4), "r"(r5), "r"(r6) 51 : "r7", "r8", "r9", "r10", "r11", "r12", 52 "cr0", "ctr", "memory"); 53 if (__builtin_expect (r0 & (1 << 28), 0)) 54 return r3; 55 return 0; 56 } 57 58 static inline void 59 futex_wait (int *addr, int val) 60 { 61 long err = sys_futex0 (addr, gomp_futex_wait, val); 62 if (__builtin_expect (err == ENOSYS, 0)) 63 { 64 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 65 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 66 sys_futex0 (addr, gomp_futex_wait, val); 67 } 68 } 69 70 static inline void 71 futex_wake (int *addr, int count) 72 { 73 long err = sys_futex0 (addr, gomp_futex_wake, count); 74 if (__builtin_expect (err == ENOSYS, 0)) 75 { 76 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; 77 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; 78 sys_futex0 (addr, gomp_futex_wake, count); 79 } 80 } 81 82 static inline void 83 cpu_relax (void) 84 { 85 __asm volatile ("" : : : "memory"); 86 } 87 88 static inline void 89 atomic_write_barrier (void) 90 { 91 __asm volatile ("eieio" : : : "memory"); 92 } 93