From 184ee94010786a9e0952aff3af39eba1d72287d3 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Fri, 17 Oct 2014 14:30:16 -0700 Subject: NPTL: Conditionalize direct futex syscall uses. --- nptl/nptl-init.c | 8 +++++--- nptl/pthread_mutex_init.c | 36 +++++++++++++++++++++--------------- nptl/pthread_mutex_lock.c | 13 +++++++++---- nptl/pthread_mutex_timedlock.c | 5 +++++ nptl/pthread_mutex_trylock.c | 5 +++++ nptl/pthread_mutex_unlock.c | 5 +++++ 6 files changed, 50 insertions(+), 22 deletions(-) (limited to 'nptl') diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index d8154c4101..a39ec9a23d 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -329,7 +329,8 @@ __pthread_initialize_minimal_internal (void) #endif set_robust_list_not_avail (); -#ifndef __ASSUME_PRIVATE_FUTEX +#ifdef __NR_futex +# ifndef __ASSUME_PRIVATE_FUTEX /* Private futexes are always used (at least internally) so that doing the test once this early is beneficial. */ { @@ -345,8 +346,8 @@ __pthread_initialize_minimal_internal (void) know the former are not supported. This also means we know the kernel will return ENOSYS for unknown operations. */ if (THREAD_GETMEM (pd, header.private_futex) != 0) -#endif -#ifndef __ASSUME_FUTEX_CLOCK_REALTIME +# endif +# ifndef __ASSUME_FUTEX_CLOCK_REALTIME { int word = 0; /* NB: the syscall actually takes six parameters. The last is the @@ -361,6 +362,7 @@ __pthread_initialize_minimal_internal (void) if (INTERNAL_SYSCALL_ERRNO (word, err) != ENOSYS) __set_futex_clock_realtime (); } +# endif #endif /* Set initial thread's stack block from 0 up to __libc_stack_end. diff --git a/nptl/pthread_mutex_init.c b/nptl/pthread_mutex_init.c index 2b3468835c..9f28b8d8dc 100644 --- a/nptl/pthread_mutex_init.c +++ b/nptl/pthread_mutex_init.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include "pthreadP.h" @@ -31,10 +32,26 @@ static const struct pthread_mutexattr default_mutexattr = }; -#ifndef __ASSUME_FUTEX_LOCK_PI -static int tpi_supported; +static bool +prio_inherit_missing (void) +{ +#ifdef __NR_futex +# ifndef __ASSUME_FUTEX_LOCK_PI + static int tpi_supported; + if (__glibc_unlikely (tpi_supported == 0)) + { + int lock = 0; + INTERNAL_SYSCALL_DECL (err); + int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI, 0, 0); + assert (INTERNAL_SYSCALL_ERROR_P (ret, err)); + tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1; + } + return __glibc_unlikely (tpi_supported < 0); +# endif + return false; #endif - + return true; +} int __pthread_mutex_init (mutex, mutexattr) @@ -58,19 +75,8 @@ __pthread_mutex_init (mutex, mutexattr) break; case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: -#ifndef __ASSUME_FUTEX_LOCK_PI - if (__glibc_unlikely (tpi_supported == 0)) - { - int lock = 0; - INTERNAL_SYSCALL_DECL (err); - int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI, - 0, 0); - assert (INTERNAL_SYSCALL_ERROR_P (ret, err)); - tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1; - } - if (__glibc_unlikely (tpi_supported < 0)) + if (__glibc_unlikely (prio_inherit_missing ())) return ENOTSUP; -#endif break; default: diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index d94f4c9483..6d4acd40c6 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -276,6 +276,10 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); break; + /* The PI support requires the Linux futex system call. If that's not + available, pthread_mutex_init should never have allowed the type to + be set. So it will get the default case for an invalid type. */ +#ifdef __NR_futex case PTHREAD_MUTEX_PI_RECURSIVE_NP: case PTHREAD_MUTEX_PI_ERRORCHECK_NP: case PTHREAD_MUTEX_PI_NORMAL_NP: @@ -321,9 +325,9 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) } int newval = id; -#ifdef NO_INCR +# ifdef NO_INCR newval |= FUTEX_WAITERS; -#endif +# endif oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, newval, 0); @@ -377,9 +381,9 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) incremented which is not correct because the old owner has to be discounted. If we are not supposed to increment __nusers we actually have to decrement it here. */ -#ifdef NO_INCR +# ifdef NO_INCR --mutex->__data.__nusers; -#endif +# endif return EOWNERDEAD; } @@ -409,6 +413,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) } } break; +#endif /* __NR_futex. */ case PTHREAD_MUTEX_PP_RECURSIVE_NP: case PTHREAD_MUTEX_PP_ERRORCHECK_NP: diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c index 57644c3365..a840f8eb6d 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -230,6 +230,10 @@ pthread_mutex_timedlock (mutex, abstime) THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); break; + /* The PI support requires the Linux futex system call. If that's not + available, pthread_mutex_init should never have allowed the type to + be set. So it will get the default case for an invalid type. */ +#ifdef __NR_futex case PTHREAD_MUTEX_PI_RECURSIVE_NP: case PTHREAD_MUTEX_PI_ERRORCHECK_NP: case PTHREAD_MUTEX_PI_NORMAL_NP: @@ -382,6 +386,7 @@ pthread_mutex_timedlock (mutex, abstime) } } break; +#endif /* __NR_futex. */ case PTHREAD_MUTEX_PP_RECURSIVE_NP: case PTHREAD_MUTEX_PP_ERRORCHECK_NP: diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c index 0867b06533..0293d0f629 100644 --- a/nptl/pthread_mutex_trylock.c +++ b/nptl/pthread_mutex_trylock.c @@ -191,6 +191,10 @@ __pthread_mutex_trylock (mutex) return 0; + /* The PI support requires the Linux futex system call. If that's not + available, pthread_mutex_init should never have allowed the type to + be set. So it will get the default case for an invalid type. */ +#ifdef __NR_futex case PTHREAD_MUTEX_PI_RECURSIVE_NP: case PTHREAD_MUTEX_PI_ERRORCHECK_NP: case PTHREAD_MUTEX_PI_NORMAL_NP: @@ -319,6 +323,7 @@ __pthread_mutex_trylock (mutex) return 0; } +#endif /* __NR_futex. */ case PTHREAD_MUTEX_PP_RECURSIVE_NP: case PTHREAD_MUTEX_PP_ERRORCHECK_NP: diff --git a/nptl/pthread_mutex_unlock.c b/nptl/pthread_mutex_unlock.c index 95ae9337c8..8064de09c1 100644 --- a/nptl/pthread_mutex_unlock.c +++ b/nptl/pthread_mutex_unlock.c @@ -158,6 +158,10 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr) THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); break; + /* The PI support requires the Linux futex system call. If that's not + available, pthread_mutex_init should never have allowed the type to + be set. So it will get the default case for an invalid type. */ +#ifdef __NR_futex case PTHREAD_MUTEX_PI_RECURSIVE_NP: /* Recursive mutex. */ if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid)) @@ -245,6 +249,7 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr) THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); break; +#endif /* __NR_futex. */ case PTHREAD_MUTEX_PP_RECURSIVE_NP: /* Recursive mutex. */ -- cgit 1.4.1