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Diffstat (limited to 'mach/lowlevellock.h')
| -rw-r--r-- | mach/lowlevellock.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/mach/lowlevellock.h b/mach/lowlevellock.h new file mode 100644 index 0000000000..8635b9db53 --- /dev/null +++ b/mach/lowlevellock.h @@ -0,0 +1,81 @@ +/* Low-level lock implementation. Mach gsync-based version. + Copyright (C) 1994-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _MACH_LOWLEVELLOCK_H +#define _MACH_LOWLEVELLOCK_H 1 + +#include <mach/gnumach.h> +#include <atomic.h> + +/* Gsync flags. */ +#ifndef GSYNC_SHARED +# define GSYNC_SHARED 0x01 +# define GSYNC_QUAD 0x02 +# define GSYNC_TIMED 0x04 +# define GSYNC_BROADCAST 0x08 +# define GSYNC_MUTATE 0x10 +#endif + +/* Static initializer for low-level locks. */ +#define LLL_INITIALIZER 0 + +/* Wait on address PTR, without blocking if its contents + * are different from VAL. */ +#define lll_wait(ptr, val, flags) \ + __gsync_wait (__mach_task_self (), \ + (vm_offset_t)(ptr), (val), 0, 0, (flags)) + +/* Wake one or more threads waiting on address PTR. */ +#define lll_wake(ptr, flags) \ + __gsync_wake (__mach_task_self (), (vm_offset_t)(ptr), 0, (flags)) + +/* Acquire the lock at PTR. */ +#define lll_lock(ptr, flags) \ + ({ \ + int *__iptr = (int *)(ptr); \ + int __flags = (flags); \ + if (*__iptr != 0 || \ + atomic_compare_and_exchange_bool_acq (__iptr, 1, 0) != 0) \ + while (1) \ + { \ + if (atomic_exchange_acq (__iptr, 2) == 0) \ + break; \ + lll_wait (__iptr, 2, __flags); \ + } \ + (void)0; \ + }) + +/* Try to acquire the lock at PTR, without blocking. + Evaluates to zero on success. */ +#define lll_trylock(ptr) \ + ({ \ + int *__iptr = (int *)(ptr); \ + *__iptr == 0 && \ + atomic_compare_and_exchange_bool_acq (__iptr, 1, 0) == 0 ? 0 : -1; \ + }) + +/* Release the lock at PTR. */ +#define lll_unlock(ptr, flags) \ + ({ \ + int *__iptr = (int *)(ptr); \ + if (atomic_exchange_rel (__iptr, 0) == 2) \ + lll_wake (__iptr, (flags)); \ + (void)0; \ + }) + +#endif |