+++ /dev/null
-/*
- * SPDX-License-Identifier: LGPL-2.1-or-later
- *
- * Copyright 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Userspace RCU - sys_futex/compat_futex header.
- */
-
-#ifndef _LTTNG_UST_FUTEX_H
-#define _LTTNG_UST_FUTEX_H
-
-#include <errno.h>
-#include <stdint.h>
-#include <time.h>
-#include <sys/syscall.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#define FUTEX_WAIT 0
-#define FUTEX_WAKE 1
-
-/*
- * sys_futex compatibility header.
- * Use *only* *either of* futex_noasync OR futex_async on a given address.
- *
- * futex_noasync cannot be executed in signal handlers, but ensures that
- * it will be put in a wait queue even in compatibility mode.
- *
- * futex_async is signal-handler safe for the wakeup. It uses polling
- * on the wait-side in compatibility mode.
- *
- * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted
- * (returns EINTR).
- */
-
-extern int lttng_ust_compat_futex_noasync(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
- __attribute__((visibility("hidden")));
-
-extern int lttng_ust_compat_futex_async(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
- __attribute__((visibility("hidden")));
-
-#if (defined(__linux__) && defined(__NR_futex))
-
-#include <unistd.h>
-#include <errno.h>
-#include <urcu/compiler.h>
-#include <urcu/arch.h>
-
-static inline int lttng_ust_futex(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- return syscall(__NR_futex, uaddr, op, val, timeout,
- uaddr2, val3);
-}
-
-static inline int lttng_ust_futex_noasync(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- int ret;
-
- ret = lttng_ust_futex(uaddr, op, val, timeout, uaddr2, val3);
- if (caa_unlikely(ret < 0 && errno == ENOSYS)) {
- /*
- * The fallback on ENOSYS is the async-safe version of
- * the compat futex implementation, because the
- * async-safe compat implementation allows being used
- * concurrently with calls to futex(). Indeed, sys_futex
- * FUTEX_WAIT, on some architectures (mips and parisc),
- * within a given process, spuriously return ENOSYS due
- * to signal restart bugs on some kernel versions.
- */
- return lttng_ust_compat_futex_async(uaddr, op, val, timeout,
- uaddr2, val3);
- }
- return ret;
-
-}
-
-static inline int lttng_ust_futex_async(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- int ret;
-
- ret = lttng_ust_futex(uaddr, op, val, timeout, uaddr2, val3);
- if (caa_unlikely(ret < 0 && errno == ENOSYS)) {
- return lttng_ust_compat_futex_async(uaddr, op, val, timeout,
- uaddr2, val3);
- }
- return ret;
-}
-
-#elif defined(__FreeBSD__)
-
-#include <sys/types.h>
-#include <sys/umtx.h>
-
-static inline int lttng_ust_futex_async(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- int umtx_op;
- void *umtx_uaddr = NULL, *umtx_uaddr2 = NULL;
- struct _umtx_time umtx_timeout = {
- ._flags = UMTX_ABSTIME,
- ._clockid = CLOCK_MONOTONIC,
- };
-
- switch (op) {
- case FUTEX_WAIT:
- /* On FreeBSD, a "u_int" is a 32-bit integer. */
- umtx_op = UMTX_OP_WAIT_UINT;
- if (timeout != NULL) {
- umtx_timeout._timeout = *timeout;
- umtx_uaddr = (void *) sizeof(umtx_timeout);
- umtx_uaddr2 = (void *) &umtx_timeout;
- }
- break;
- case FUTEX_WAKE:
- umtx_op = UMTX_OP_WAKE;
- break;
- default:
- errno = EINVAL;
- return -1;
- }
-
- return _umtx_op(uaddr, umtx_op, (uint32_t) val, umtx_uaddr,
- umtx_uaddr2);
-}
-
-static inline int lttng_ust_futex_noasync(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- return lttng_ust_futex_async(uaddr, op, val, timeout, uaddr2, val3);
-}
-
-#elif defined(__CYGWIN__)
-
-/*
- * The futex_noasync compat code uses a weak symbol to share state across
- * different shared object which is not possible on Windows with the
- * Portable Executable format. Use the async compat code for both cases.
- */
-static inline int lttng_ust_futex_noasync(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- return lttng_ust_compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
-}
-
-static inline int lttng_ust_futex_async(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- return lttng_ust_compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
-}
-
-#else
-
-static inline int lttng_ust_futex_noasync(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- return lttng_ust_compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3);
-}
-
-static inline int lttng_ust_futex_async(int32_t *uaddr, int op, int32_t val,
- const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
-{
- return lttng_ust_compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
-}
-
-#endif
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* _LTTNG_UST_FUTEX_H */
projects / lttng-ust.git / blobdiff