diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/nacl/exit-thread.h | 4 | ||||
| -rw-r--r-- | sysdeps/nacl/futex-internal.h | 248 | ||||
| -rw-r--r-- | sysdeps/nptl/aio_misc.h | 16 | ||||
| -rw-r--r-- | sysdeps/nptl/fork.c | 3 | ||||
| -rw-r--r-- | sysdeps/nptl/futex-internal.h | 203 | ||||
| -rw-r--r-- | sysdeps/nptl/gai_misc.h | 16 | ||||
| -rw-r--r-- | sysdeps/sparc/nptl/pthread_barrier_init.c | 7 | ||||
| -rw-r--r-- | sysdeps/sparc/nptl/pthread_barrier_wait.c | 6 | ||||
| -rw-r--r-- | sysdeps/sparc/sparc32/pthread_barrier_wait.c | 6 | ||||
| -rw-r--r-- | sysdeps/sparc/sparc32/sem_init.c | 29 | ||||
| -rw-r--r-- | sysdeps/sparc/sparc32/sem_open.c | 2 | ||||
| -rw-r--r-- | sysdeps/sparc/sparc32/sem_post.c | 26 | ||||
| -rw-r--r-- | sysdeps/sparc/sparc32/sem_wait.c | 1 | ||||
| -rw-r--r-- | sysdeps/sparc/sparc32/sem_waitcommon.c | 107 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/futex-internal.h | 251 |
15 files changed, 751 insertions, 174 deletions
diff --git a/sysdeps/nacl/exit-thread.h b/sysdeps/nacl/exit-thread.h index c809405..915f93d 100644 --- a/sysdeps/nacl/exit-thread.h +++ b/sysdeps/nacl/exit-thread.h @@ -18,7 +18,7 @@ #include <assert.h> #include <atomic.h> -#include <lowlevellock.h> +#include <futex-internal.h> #include <nacl-interfaces.h> #include <nptl/pthreadP.h> @@ -64,7 +64,7 @@ __exit_thread (void) assert (NACL_EXITING_TID > 0); atomic_store_relaxed (&pd->tid, NACL_EXITING_TID); - lll_futex_wake (&pd->tid, 1, LLL_PRIVATE); + futex_wake ((unsigned int *) &pd->tid, 1, FUTEX_PRIVATE); } /* This clears PD->tid some time after the thread stack can never diff --git a/sysdeps/nacl/futex-internal.h b/sysdeps/nacl/futex-internal.h new file mode 100644 index 0000000..593bb9d --- /dev/null +++ b/sysdeps/nacl/futex-internal.h @@ -0,0 +1,248 @@ +/* futex operations for glibc-internal use. NaCl version. + Copyright (C) 2014-2015 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 FUTEX_INTERNAL_H +#define FUTEX_INTERNAL_H + +#include <sysdeps/nptl/futex-internal.h> +#include <errno.h> +#include <lowlevellock-futex.h> +#include <nacl-interfaces.h> +#include <nptl/pthreadP.h> + +/* See sysdeps/nptl/futex-internal.h for documentation; this file only + contains NaCl-specific comments. + + There is no support yet for shared futexes nor for exact relative + timeouts. */ + +/* See sysdeps/nptl/futex-internal.h for constraints on the value of the + FUTEX_PRIVATE and FUTEX_SHARED constants. + Shared futexes are not yet supported, and we never allow clients to + actually request shared futexes. Therefore, we do not need a different + value. */ +#undef FUTEX_SHARED +#define FUTEX_SHARED FUTEX_PRIVATE + +/* FUTEX_SHARED is not yet supported. */ +static __always_inline int +futex_supports_pshared (int pshared) +{ + if (__glibc_likely (pshared == PTHREAD_PROCESS_PRIVATE)) + return 0; + else if (pshared == PTHREAD_PROCESS_SHARED) + return ENOTSUP; + else + return EINVAL; +} + +/* Relative timeouts are only emulated via absolute timeouts using the + system clock. */ +static __always_inline bool +futex_supports_exact_relative_timeouts (void) +{ + return false; +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_wait (unsigned int *futex_word, unsigned int expected, int private) +{ + int err = lll_futex_timed_wait (futex_word, expected, NULL, private); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + return -err; + + case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */ + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_wait_cancelable (unsigned int *futex_word, unsigned int expected, + int private) +{ + int oldtype; + oldtype = __pthread_enable_asynccancel (); + int err = lll_futex_timed_wait (futex_word, expected, NULL, private); + __pthread_disable_asynccancel (oldtype); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + return -err; + + case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */ + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_reltimed_wait (unsigned int *futex_word, unsigned int expected, + const struct timespec *reltime, int private) +{ + int err = lll_futex_timed_wait (futex_word, expected, reltime, private); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + case -ETIMEDOUT: + return -err; + + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_reltimed_wait_cancelable (unsigned int *futex_word, + unsigned int expected, + const struct timespec *reltime, int private) +{ + int oldtype; + oldtype = __pthread_enable_asynccancel (); + int err = lll_futex_timed_wait (futex_word, expected, reltime, private); + __pthread_disable_asynccancel (oldtype); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + case -ETIMEDOUT: + return -err; + + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_abstimed_wait (unsigned int *futex_word, unsigned int expected, + const struct timespec *abstime, int private) +{ + int err = __nacl_irt_futex.futex_wait_abs ((volatile int *) futex_word, + expected, abstime); + switch (err) + { + case 0: + case EAGAIN: + case EINTR: + case ETIMEDOUT: + return err; + + case EFAULT: /* Must have been caused by a glibc or application bug. */ + case EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_abstimed_wait_cancelable (unsigned int *futex_word, + unsigned int expected, + const struct timespec *abstime, int private) +{ + int oldtype; + oldtype = __pthread_enable_asynccancel (); + int err = __nacl_irt_futex.futex_wait_abs ((volatile int *) futex_word, + expected, abstime); + __pthread_disable_asynccancel (oldtype); + switch (err) + { + case 0: + case EAGAIN: + case EINTR: + case ETIMEDOUT: + return err; + + case EFAULT: /* Must have been caused by a glibc or application bug. */ + case EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline void +futex_wake (unsigned int *futex_word, int processes_to_wake, int private) +{ + int res = lll_futex_wake (futex_word, processes_to_wake, private); + /* No error. Ignore the number of woken processes. */ + if (res >= 0) + return; + switch (res) + { + case -EFAULT: /* Could have happened due to memory reuse. */ + case -EINVAL: /* Could be either due to incorrect alignment (a bug in + glibc or in the application) or due to memory being + reused for a PI futex. We cannot distinguish between the + two causes, and one of them is correct use, so we do not + act in this case. */ + return; + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +#endif /* futex-internal.h */ diff --git a/sysdeps/nptl/aio_misc.h b/sysdeps/nptl/aio_misc.h index d5d1c08..4a6ebfc 100644 --- a/sysdeps/nptl/aio_misc.h +++ b/sysdeps/nptl/aio_misc.h @@ -22,14 +22,14 @@ #include <assert.h> #include <nptl/pthreadP.h> -#include <lowlevellock.h> +#include <futex-internal.h> #define DONT_NEED_AIO_MISC_COND 1 #define AIO_MISC_NOTIFY(waitlist) \ do { \ if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \ - lll_futex_wake (waitlist->counterp, 1, LLL_PRIVATE); \ + futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \ } while (0) #define AIO_MISC_WAIT(result, futex, timeout, cancel) \ @@ -48,9 +48,9 @@ int status; \ do \ { \ - status = lll_futex_timed_wait (futexaddr, oldval, timeout, \ - LLL_PRIVATE); \ - if (status != -EWOULDBLOCK) \ + status = futex_reltimed_wait ((unsigned int *) futexaddr, oldval, \ + timeout, FUTEX_PRIVATE); \ + if (status != EAGAIN) \ break; \ \ oldval = *futexaddr; \ @@ -60,12 +60,12 @@ if (cancel) \ LIBC_CANCEL_RESET (oldtype); \ \ - if (status == -EINTR) \ + if (status == EINTR) \ result = EINTR; \ - else if (status == -ETIMEDOUT) \ + else if (status == ETIMEDOUT) \ result = EAGAIN; \ else \ - assert (status == 0 || status == -EWOULDBLOCK); \ + assert (status == 0 || status == EAGAIN); \ \ pthread_mutex_lock (&__aio_requests_mutex); \ } \ diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c index 74482b7..2b9ae4b 100644 --- a/sysdeps/nptl/fork.c +++ b/sysdeps/nptl/fork.c @@ -30,6 +30,7 @@ #include <nptl/pthreadP.h> #include <fork.h> #include <arch-fork.h> +#include <futex-internal.h> static void @@ -219,7 +220,7 @@ __libc_fork (void) if (atomic_decrement_and_test (&allp->handler->refcntr) && allp->handler->need_signal) - lll_futex_wake (&allp->handler->refcntr, 1, LLL_PRIVATE); + futex_wake (&allp->handler->refcntr, 1, FUTEX_PRIVATE); allp = allp->next; } diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h new file mode 100644 index 0000000..4f8c8fe --- /dev/null +++ b/sysdeps/nptl/futex-internal.h @@ -0,0 +1,203 @@ +/* futex operations for glibc-internal use. Stub version; do not include + this file directly. + Copyright (C) 2014-2015 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 STUB_FUTEX_INTERNAL_H +#define STUB_FUTEX_INTERNAL_H + +#include <sys/time.h> +#include <stdio.h> +#include <stdbool.h> +#include <libc-internal.h> + +/* This file defines futex operations used internally in glibc. A futex + consists of the so-called futex word in userspace, which is of type + unsigned int and represents an application-specific condition, and kernel + state associated with this particular futex word (e.g., wait queues). The + futex operations we provide are wrappers for the futex syscalls and add + glibc-specific error checking of the syscall return value. We abort on + error codes that are caused by bugs in glibc or in the calling application, + or when an error code is not known. We return error codes that can arise + in correct executions to the caller. Each operation calls out exactly the + return values that callers need to handle. + + The private flag must be either FUTEX_PRIVATE or FUTEX_SHARED. + FUTEX_PRIVATE is always supported, and the implementation can internally + use FUTEX_SHARED when FUTEX_PRIVATE is requested. FUTEX_SHARED is not + necessarily supported (use futex_supports_pshared to detect this). + + We expect callers to only use these operations if futexes and the + specific futex operations being used are supported (e.g., FUTEX_SHARED). + + Given that waking other threads waiting on a futex involves concurrent + accesses to the futex word, you must use atomic operations to access the + futex word. + + Both absolute and relative timeouts can be used. An absolute timeout + expires when the given specific point in time on the CLOCK_REALTIME clock + passes, or when it already has passed. A relative timeout expires when + the given duration of time on the CLOCK_MONOTONIC clock passes. Relative + timeouts may be imprecise (see futex_supports_exact_relative_timeouts). + + Due to POSIX requirements on when synchronization data structures such + as mutexes or semaphores can be destroyed and due to the futex design + having separate fast/slow paths for wake-ups, we need to consider that + futex_wake calls might effectively target a data structure that has been + destroyed and reused for another object, or unmapped; thus, some + errors or spurious wake-ups can happen in correct executions that would + not be possible in a program using just a single futex whose lifetime + does not end before the program terminates. For background, see: + https://sourceware.org/ml/libc-alpha/2014-04/msg00075.html + https://lkml.org/lkml/2014/11/27/472 */ + +/* Defined this way for interoperability with lowlevellock. + FUTEX_PRIVATE must be zero because the initializers for pthread_mutex_t, + pthread_rwlock_t, and pthread_cond_t initialize the respective field of + those structures to zero, and we want FUTEX_PRIVATE to be the default. */ +#define FUTEX_PRIVATE LLL_PRIVATE +#define FUTEX_SHARED LLL_SHARED +#if FUTEX_PRIVATE != 0 +# error FUTEX_PRIVATE must be equal to 0 +#endif + +/* Returns EINVAL if PSHARED is neither PTHREAD_PROCESS_PRIVATE nor + PTHREAD_PROCESS_SHARED; otherwise, returns 0 if PSHARED is supported, and + ENOTSUP if not. */ +static __always_inline int +futex_supports_pshared (int pshared); + +/* Returns true if relative timeouts are robust to concurrent changes to the + system clock. If this returns false, relative timeouts can still be used + but might be effectively longer or shorter than requested. */ +static __always_inline bool +futex_supports_exact_relative_timeouts (void); + +/* Atomically wrt other futex operations on the same futex, this blocks iff + the value *FUTEX_WORD matches the expected value. This is + semantically equivalent to: + l = <get lock associated with futex> (FUTEX_WORD); + wait_flag = <get wait_flag associated with futex> (FUTEX_WORD); + lock (l); + val = atomic_load_relaxed (FUTEX_WORD); + if (val != expected) { unlock (l); return EAGAIN; } + atomic_store_relaxed (wait_flag, true); + unlock (l); + // Now block; can time out in futex_time_wait (see below) + while (atomic_load_relaxed(wait_flag) && !<spurious wake-up>); + + Note that no guarantee of a happens-before relation between a woken + futex_wait and a futex_wake is documented; however, this does not matter + in practice because we have to consider spurious wake-ups (see below), + and thus would not be able to reliably reason about which futex_wake woke + us. + + Returns 0 if woken by a futex operation or spuriously. (Note that due to + the POSIX requirements mentioned above, we need to conservatively assume + that unrelated futex_wake operations could wake this futex; it is easiest + to just be prepared for spurious wake-ups.) + Returns EAGAIN if the futex word did not match the expected value. + Returns EINTR if waiting was interrupted by a signal. + + Note that some previous code in glibc assumed the underlying futex + operation (e.g., syscall) to start with or include the equivalent of a + seq_cst fence; this allows one to avoid an explicit seq_cst fence before + a futex_wait call when synchronizing similar to Dekker synchronization. + However, we make no such guarantee here. */ +static __always_inline int +futex_wait (unsigned int *futex_word, unsigned int expected, int private); + +/* Like futex_wait but does not provide any indication why we stopped waiting. + Thus, when this function returns, you have to always check FUTEX_WORD to + determine whether you need to continue waiting, and you cannot detect + whether the waiting was interrupted by a signal. Example use: + while (atomic_load_relaxed (&futex_word) == 23) + futex_wait_simple (&futex_word, 23, FUTEX_PRIVATE); + This is common enough to make providing this wrapper worthwhile. */ +static __always_inline void +futex_wait_simple (unsigned int *futex_word, unsigned int expected, + int private) +{ + ignore_value (futex_wait (futex_word, expected, private)); +} + + +/* Like futex_wait but is a POSIX cancellation point. */ +static __always_inline int +futex_wait_cancelable (unsigned int *futex_word, unsigned int expected, + int private); + +/* Like futex_wait, but will eventually time out (i.e., stop being + blocked) after the duration of time provided (i.e., RELTIME) has + passed. The caller must provide a normalized RELTIME. RELTIME can also + equal NULL, in which case this function behaves equivalent to futex_wait. + + Returns the same values as futex_wait under those same conditions; + additionally, returns ETIMEDOUT if the timeout expired. + */ +static __always_inline int +futex_reltimed_wait (unsigned int* futex_word, unsigned int expected, + const struct timespec* reltime, int private); + +/* Like futex_reltimed_wait but is a POSIX cancellation point. */ +static __always_inline int +futex_reltimed_wait_cancelable (unsigned int* futex_word, + unsigned int expected, + const struct timespec* reltime, int private); + +/* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an + absolute point in time; a call will time out after this point in time. */ +static __always_inline int +futex_abstimed_wait (unsigned int* futex_word, unsigned int expected, + const struct timespec* abstime, int private); + +/* Like futex_reltimed_wait but is a POSIX cancellation point. */ +static __always_inline int +futex_abstimed_wait_cancelable (unsigned int* futex_word, + unsigned int expected, + const struct timespec* abstime, int private); + +/* Atomically wrt other futex operations on the same futex, this unblocks the + specified number of processes, or all processes blocked on this futex if + there are fewer than the specified number. Semantically, this is + equivalent to: + l = <get lock associated with futex> (FUTEX_WORD); + lock (l); + for (res = 0; PROCESSES_TO_WAKE > 0; PROCESSES_TO_WAKE--, res++) { + if (<no process blocked on futex>) break; + wf = <get wait_flag of a process blocked on futex> (FUTEX_WORD); + // No happens-before guarantee with woken futex_wait (see above) + atomic_store_relaxed (wf, 0); + } + return res; + + Note that we need to support futex_wake calls to past futexes whose memory + has potentially been reused due to POSIX' requirements on synchronization + object destruction (see above); therefore, we must not report or abort + on most errors. */ +static __always_inline void +futex_wake (unsigned int* futex_word, int processes_to_wake, int private); + +/* Calls __libc_fatal with an error message. Convenience function for + concrete implementations of the futex interface. */ +static __always_inline __attribute__ ((__noreturn__)) void +futex_fatal_error (void) +{ + __libc_fatal ("The futex facility returned an unexpected error code."); +} + +#endif /* futex-internal.h */ diff --git a/sysdeps/nptl/gai_misc.h b/sysdeps/nptl/gai_misc.h index a34dbc0..96c8fa0 100644 --- a/sysdeps/nptl/gai_misc.h +++ b/sysdeps/nptl/gai_misc.h @@ -23,14 +23,14 @@ #include <assert.h> #include <signal.h> #include <nptl/pthreadP.h> -#include <lowlevellock.h> +#include <futex-internal.h> #define DONT_NEED_GAI_MISC_COND 1 #define GAI_MISC_NOTIFY(waitlist) \ do { \ if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \ - lll_futex_wake (waitlist->counterp, 1, LLL_PRIVATE); \ + futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \ } while (0) #define GAI_MISC_WAIT(result, futex, timeout, cancel) \ @@ -49,9 +49,9 @@ int status; \ do \ { \ - status = lll_futex_timed_wait (futexaddr, oldval, timeout, \ - LLL_PRIVATE); \ - if (status != -EWOULDBLOCK) \ + status = futex_reltimed_wait ((unsigned int *) futexaddr, oldval, \ + timeout, FUTEX_PRIVATE); \ + if (status != EAGAIN) \ break; \ \ oldval = *futexaddr; \ @@ -61,12 +61,12 @@ if (cancel) \ LIBC_CANCEL_RESET (oldtype); \ \ - if (status == -EINTR) \ + if (status == EINTR) \ result = EINTR; \ - else if (status == -ETIMEDOUT) \ + else if (status == ETIMEDOUT) \ result = EAGAIN; \ else \ - assert (status == 0 || status == -EWOULDBLOCK); \ + assert (status == 0 || status == EAGAIN); \ \ pthread_mutex_lock (&__gai_requests_mutex); \ } \ diff --git a/sysdeps/sparc/nptl/pthread_barrier_init.c b/sysdeps/sparc/nptl/pthread_barrier_init.c index aa21a63..86ec7d0 100644 --- a/sysdeps/sparc/nptl/pthread_barrier_init.c +++ b/sysdeps/sparc/nptl/pthread_barrier_init.c @@ -35,10 +35,9 @@ __pthread_barrier_init (barrier, attr, count) struct pthread_barrierattr *iattr = (struct pthread_barrierattr *) attr; if (iattr != NULL) { - if (iattr->pshared != PTHREAD_PROCESS_PRIVATE - && __builtin_expect (iattr->pshared != PTHREAD_PROCESS_SHARED, 0)) - /* Invalid attribute. */ - return EINVAL; + int err = futex_supports_pshared (iattr->pshared); + if (err != 0) + return err; } ibarrier = (union sparc_pthread_barrier *) barrier; diff --git a/sysdeps/sparc/nptl/pthread_barrier_wait.c b/sysdeps/sparc/nptl/pthread_barrier_wait.c index dd4c336..9e9806a 100644 --- a/sysdeps/sparc/nptl/pthread_barrier_wait.c +++ b/sysdeps/sparc/nptl/pthread_barrier_wait.c @@ -21,6 +21,7 @@ #include <lowlevellock.h> #include <pthreadP.h> #include <sparc-nptl.h> +#include <futex-internal.h> /* Wait on barrier. */ int @@ -31,6 +32,7 @@ __pthread_barrier_wait (barrier) = (union sparc_pthread_barrier *) barrier; int result = 0; int private = ibarrier->s.pshared ? LLL_SHARED : LLL_PRIVATE; + int futex_private = ibarrier->s.pshared ? FUTEX_SHARED : FUTEX_PRIVATE; /* Make sure we are alone. */ lll_lock (ibarrier->b.lock, private); @@ -46,7 +48,7 @@ __pthread_barrier_wait (barrier) ++ibarrier->b.curr_event; /* Wake up everybody. */ - lll_futex_wake (&ibarrier->b.curr_event, INT_MAX, private); + futex_wake (&ibarrier->b.curr_event, INT_MAX, futex_private); /* This is the thread which finished the serialization. */ result = PTHREAD_BARRIER_SERIAL_THREAD; @@ -62,7 +64,7 @@ __pthread_barrier_wait (barrier) /* Wait for the event counter of the barrier to change. */ do - lll_futex_wait (&ibarrier->b.curr_event, event, private); + futex_wait_simple (&ibarrier->b.curr_event, event, futex_private); while (event == ibarrier->b.curr_event); } diff --git a/sysdeps/sparc/sparc32/pthread_barrier_wait.c b/sysdeps/sparc/sparc32/pthread_barrier_wait.c index 81d22b0..5e1aa11 100644 --- a/sysdeps/sparc/sparc32/pthread_barrier_wait.c +++ b/sysdeps/sparc/sparc32/pthread_barrier_wait.c @@ -21,6 +21,7 @@ #include <lowlevellock.h> #include <pthreadP.h> #include <sparc-nptl.h> +#include <futex-internal.h> /* Wait on barrier. */ int @@ -31,6 +32,7 @@ __pthread_barrier_wait (barrier) = (union sparc_pthread_barrier *) barrier; int result = 0; int private = ibarrier->s.pshared ? LLL_SHARED : LLL_PRIVATE; + int futex_private = ibarrier->s.pshared ? FUTEX_SHARED : FUTEX_PRIVATE; /* Make sure we are alone. */ lll_lock (ibarrier->b.lock, private); @@ -46,7 +48,7 @@ __pthread_barrier_wait (barrier) ++ibarrier->b.curr_event; /* Wake up everybody. */ - lll_futex_wake (&ibarrier->b.curr_event, INT_MAX, private); + futex_wake (&ibarrier->b.curr_event, INT_MAX, futex_private); /* This is the thread which finished the serialization. */ result = PTHREAD_BARRIER_SERIAL_THREAD; @@ -62,7 +64,7 @@ __pthread_barrier_wait (barrier) /* Wait for the event counter of the barrier to change. */ do - lll_futex_wait (&ibarrier->b.curr_event, event, private); + futex_wait_simple (&ibarrier->b.curr_event, event, futex_private); while (event == ibarrier->b.curr_event); } diff --git a/sysdeps/sparc/sparc32/sem_init.c b/sysdeps/sparc/sparc32/sem_init.c index 7c46cee..1c7c455 100644 --- a/sysdeps/sparc/sparc32/sem_init.c +++ b/sysdeps/sparc/sparc32/sem_init.c @@ -20,23 +20,7 @@ #include <semaphore.h> #include <shlib-compat.h> #include "semaphoreP.h" -#include <kernel-features.h> - -/* Returns FUTEX_PRIVATE if pshared is zero and private futexes are supported; - returns FUTEX_SHARED otherwise. - TODO Remove when cleaning up the futex API throughout glibc. */ -static __always_inline int -futex_private_if_supported (int pshared) -{ - if (pshared != 0) - return LLL_SHARED; -#ifdef __ASSUME_PRIVATE_FUTEX - return LLL_PRIVATE; -#else - return THREAD_GETMEM (THREAD_SELF, header.private_futex) - ^ FUTEX_PRIVATE_FLAG; -#endif -} +#include <futex-internal.h> int @@ -49,6 +33,14 @@ __new_sem_init (sem_t *sem, int pshared, unsigned int value) return -1; } + pshared = pshared != 0 ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE; + int err = futex_supports_pshared (pshared); + if (err != 0) + { + __set_errno (err); + return -1; + } + /* Map to the internal type. */ struct new_sem *isem = (struct new_sem *) sem; @@ -57,7 +49,8 @@ __new_sem_init (sem_t *sem, int pshared, unsigned int value) isem->pad = 0; isem->nwaiters = 0; - isem->private = futex_private_if_supported (pshared); + isem->private = (pshared == PTHREAD_PROCESS_PRIVATE + ? FUTEX_PRIVATE : FUTEX_SHARED); return 0; } diff --git a/sysdeps/sparc/sparc32/sem_open.c b/sysdeps/sparc/sparc32/sem_open.c index 2698d19..16cb9ad 100644 --- a/sysdeps/sparc/sparc32/sem_open.c +++ b/sysdeps/sparc/sparc32/sem_open.c @@ -199,7 +199,7 @@ sem_open (const char *name, int oflag, ...) sem.newsem.nwaiters = 0; /* This always is a shared semaphore. */ - sem.newsem.private = LLL_SHARED; + sem.newsem.private = FUTEX_SHARED; /* Initialize the remaining bytes as well. */ memset ((char *) &sem.initsem + sizeof (struct new_sem), '\0', diff --git a/sysdeps/sparc/sparc32/sem_post.c b/sysdeps/sparc/sparc32/sem_post.c index c9f85a0..fd1a2fe 100644 --- a/sysdeps/sparc/sparc32/sem_post.c +++ b/sysdeps/sparc/sparc32/sem_post.c @@ -23,34 +23,10 @@ #include <lowlevellock.h> #include <internaltypes.h> #include <semaphore.h> +#include <futex-internal.h> #include <shlib-compat.h> -/* Wrapper for lll_futex_wake, with error checking. - TODO Remove when cleaning up the futex API throughout glibc. */ -static __always_inline void -futex_wake (unsigned int* futex, int processes_to_wake, int private) -{ - int res = lll_futex_wake (futex, processes_to_wake, private); - /* No error. Ignore the number of woken processes. */ - if (res >= 0) - return; - switch (res) - { - case -EFAULT: /* Could have happened due to memory reuse. */ - case -EINVAL: /* Could be either due to incorrect alignment (a bug in - glibc or in the application) or due to memory being - reused for a PI futex. We cannot distinguish between the - two causes, and one of them is correct use, so we do not - act in this case. */ - return; - case -ENOSYS: /* Must have been caused by a glibc bug. */ - /* No other errors are documented at this time. */ - default: - abort (); - } -} - /* See sem_wait for an explanation of the algorithm. */ int diff --git a/sysdeps/sparc/sparc32/sem_wait.c b/sysdeps/sparc/sparc32/sem_wait.c index c1fd10c..fce7ed4 100644 --- a/sysdeps/sparc/sparc32/sem_wait.c +++ b/sysdeps/sparc/sparc32/sem_wait.c @@ -17,6 +17,7 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ +#include <lowlevellock.h> /* lll_futex* used by the old code. */ #include "sem_waitcommon.c" int diff --git a/sysdeps/sparc/sparc32/sem_waitcommon.c b/sysdeps/sparc/sparc32/sem_waitcommon.c index 9c1c6a5..9e43d45 100644 --- a/sysdeps/sparc/sparc32/sem_waitcommon.c +++ b/sysdeps/sparc/sparc32/sem_waitcommon.c @@ -19,7 +19,7 @@ #include <errno.h> #include <sysdep.h> -#include <lowlevellock.h> +#include <futex-internal.h> #include <internaltypes.h> #include <semaphore.h> #include <sys/time.h> @@ -28,104 +28,6 @@ #include <shlib-compat.h> #include <atomic.h> -/* Wrapper for lll_futex_wait with absolute timeout and error checking. - TODO Remove when cleaning up the futex API throughout glibc. */ -static __always_inline int -futex_abstimed_wait (unsigned int* futex, unsigned int expected, - const struct timespec* abstime, int private, bool cancel) -{ - int err, oldtype; - if (abstime == NULL) - { - if (cancel) - oldtype = __pthread_enable_asynccancel (); - err = lll_futex_wait (futex, expected, private); - if (cancel) - __pthread_disable_asynccancel (oldtype); - } - else - { - struct timeval tv; - struct timespec rt; - int sec, nsec; - - /* Get the current time. */ - __gettimeofday (&tv, NULL); - - /* Compute relative timeout. */ - sec = abstime->tv_sec - tv.tv_sec; - nsec = abstime->tv_nsec - tv.tv_usec * 1000; - if (nsec < 0) - { - nsec += 1000000000; - --sec; - } - - /* Already timed out? */ - if (sec < 0) - return ETIMEDOUT; - - /* Do wait. */ - rt.tv_sec = sec; - rt.tv_nsec = nsec; - if (cancel) - oldtype = __pthread_enable_asynccancel (); - err = lll_futex_timed_wait (futex, expected, &rt, private); - if (cancel) - __pthread_disable_asynccancel (oldtype); - } - switch (err) - { - case 0: - case -EAGAIN: - case -EINTR: - case -ETIMEDOUT: - return -err; - - case -EFAULT: /* Must have been caused by a glibc or application bug. */ - case -EINVAL: /* Either due to wrong alignment or due to the timeout not - being normalized. Must have been caused by a glibc or - application bug. */ - case -ENOSYS: /* Must have been caused by a glibc bug. */ - /* No other errors are documented at this time. */ - default: - abort (); - } -} - -/* Wrapper for lll_futex_wake, with error checking. - TODO Remove when cleaning up the futex API throughout glibc. */ -static __always_inline void -futex_wake (unsigned int* futex, int processes_to_wake, int private) -{ - int res = lll_futex_wake (futex, processes_to_wake, private); - /* No error. Ignore the number of woken processes. */ - if (res >= 0) - return; - switch (res) - { - case -EFAULT: /* Could have happened due to memory reuse. */ - case -EINVAL: /* Could be either due to incorrect alignment (a bug in - glibc or in the application) or due to memory being - reused for a PI futex. We cannot distinguish between the - two causes, and one of them is correct use, so we do not - act in this case. */ - return; - case -ENOSYS: /* Must have been caused by a glibc bug. */ - /* No other errors are documented at this time. */ - default: - abort (); - } -} - - -/* Set this to true if you assume that, in contrast to current Linux futex - documentation, lll_futex_wake can return -EINTR only if interrupted by a - signal, not spuriously due to some other reason. - TODO Discuss EINTR conditions with the Linux kernel community. For - now, we set this to true to not change behavior of semaphores compared - to previous glibc builds. */ -static const int sem_assume_only_signals_cause_futex_EINTR = 1; static void __sem_wait_32_finish (struct new_sem *sem); @@ -149,8 +51,8 @@ do_futex_wait (struct new_sem *sem, const struct timespec *abstime) { int err; - err = futex_abstimed_wait (&sem->value, SEM_NWAITERS_MASK, abstime, - sem->private, true); + err = futex_abstimed_wait_cancelable (&sem->value, SEM_NWAITERS_MASK, + abstime, sem->private); return err; } @@ -202,8 +104,7 @@ __new_sem_wait_slow (struct new_sem *sem, const struct timespec *abstime) __sparc32_atomic_do_unlock24(&sem->pad); err = do_futex_wait(sem, abstime); - if (err == ETIMEDOUT || - (err == EINTR && sem_assume_only_signals_cause_futex_EINTR)) + if (err == ETIMEDOUT || err == EINTR) { __set_errno (err); err = -1; diff --git a/sysdeps/unix/sysv/linux/futex-internal.h b/sysdeps/unix/sysv/linux/futex-internal.h new file mode 100644 index 0000000..aca0911 --- /dev/null +++ b/sysdeps/unix/sysv/linux/futex-internal.h @@ -0,0 +1,251 @@ +/* futex operations for glibc-internal use. Linux version. + Copyright (C) 2014-2015 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 FUTEX_INTERNAL_H +#define FUTEX_INTERNAL_H + +#include <sysdeps/nptl/futex-internal.h> +#include <errno.h> +#include <lowlevellock-futex.h> +#include <nptl/pthreadP.h> + +/* See sysdeps/nptl/futex-internal.h for documentation; this file only + contains Linux-specific comments. + + The Linux kernel treats provides absolute timeouts based on the + CLOCK_REALTIME clock and relative timeouts measured against the + CLOCK_MONOTONIC clock. + + We expect a Linux kernel version of 2.6.22 or more recent (since this + version, EINTR is not returned on spurious wake-ups anymore). */ + +/* FUTEX_SHARED is always supported by the Linux kernel. */ +static __always_inline int +futex_supports_pshared (int pshared) +{ + if (__glibc_likely (pshared == PTHREAD_PROCESS_PRIVATE)) + return 0; + else if (pshared == PTHREAD_PROCESS_SHARED) + return 0; + else + return EINVAL; +} + +/* The Linux kernel supports relative timeouts measured against the + CLOCK_MONOTONIC clock. */ +static __always_inline bool +futex_supports_exact_relative_timeouts (void) +{ + return true; +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_wait (unsigned int *futex_word, unsigned int expected, int private) +{ + int err = lll_futex_timed_wait (futex_word, expected, NULL, private); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + return -err; + + case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */ + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_wait_cancelable (unsigned int *futex_word, unsigned int expected, + int private) +{ + int oldtype; + oldtype = __pthread_enable_asynccancel (); + int err = lll_futex_timed_wait (futex_word, expected, NULL, private); + __pthread_disable_asynccancel (oldtype); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + return -err; + + case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */ + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_reltimed_wait (unsigned int *futex_word, unsigned int expected, + const struct timespec *reltime, int private) +{ + int err = lll_futex_timed_wait (futex_word, expected, reltime, private); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + case -ETIMEDOUT: + return -err; + + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_reltimed_wait_cancelable (unsigned int *futex_word, + unsigned int expected, + const struct timespec *reltime, int private) +{ + int oldtype; + oldtype = __pthread_enable_asynccancel (); + int err = lll_futex_timed_wait (futex_word, expected, reltime, private); + __pthread_disable_asynccancel (oldtype); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + case -ETIMEDOUT: + return -err; + + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_abstimed_wait (unsigned int *futex_word, unsigned int expected, + const struct timespec *abstime, int private) +{ + /* Work around the fact that the kernel rejects negative timeout values + despite them being valid. */ + if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0))) + return ETIMEDOUT; + int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime, + FUTEX_CLOCK_REALTIME, private); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + case -ETIMEDOUT: + return -err; + + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline int +futex_abstimed_wait_cancelable (unsigned int *futex_word, + unsigned int expected, + const struct timespec *abstime, int private) +{ + /* Work around the fact that the kernel rejects negative timeout values + despite them being valid. */ + if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0))) + return ETIMEDOUT; + int oldtype; + oldtype = __pthread_enable_asynccancel (); + int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime, + FUTEX_CLOCK_REALTIME, private); + __pthread_disable_asynccancel (oldtype); + switch (err) + { + case 0: + case -EAGAIN: + case -EINTR: + case -ETIMEDOUT: + return -err; + + case -EFAULT: /* Must have been caused by a glibc or application bug. */ + case -EINVAL: /* Either due to wrong alignment or due to the timeout not + being normalized. Must have been caused by a glibc or + application bug. */ + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +/* See sysdeps/nptl/futex-internal.h for details. */ +static __always_inline void +futex_wake (unsigned int *futex_word, int processes_to_wake, int private) +{ + int res = lll_futex_wake (futex_word, processes_to_wake, private); + /* No error. Ignore the number of woken processes. */ + if (res >= 0) + return; + switch (res) + { + case -EFAULT: /* Could have happened due to memory reuse. */ + case -EINVAL: /* Could be either due to incorrect alignment (a bug in + glibc or in the application) or due to memory being + reused for a PI futex. We cannot distinguish between the + two causes, and one of them is correct use, so we do not + act in this case. */ + return; + case -ENOSYS: /* Must have been caused by a glibc bug. */ + /* No other errors are documented at this time. */ + default: + futex_fatal_error (); + } +} + +#endif /* futex-internal.h */ |