From patchwork Mon Jun 9 20:24:46 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bernard Ogden X-Patchwork-Id: 357600 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id D948514008D for ; Tue, 10 Jun 2014 06:25:09 +1000 (EST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:content-type:content-transfer-encoding :subject:message-id:date:to:mime-version; q=dns; s=default; b=Vq 50O9uSONxlzWMxGKS62dnicxD0+v3OyBZnbtmMLDNf+NUwrtRawz4StsGM60MbFt K+8uEw+a5bBAn7gG6s4YrlKuZeV1JBkUeJg5HUmI000/0XRGC2H1yDqpmrrgslaU 5PouPyW7/oeZoJljYVhA1aL1OrcsVoqqSFTQgzlqs= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:content-type:content-transfer-encoding :subject:message-id:date:to:mime-version; s=default; bh=jrkhSSGe EC9WiHqIVMHbuTCaw3Q=; b=BKykBDqmOLwotS1b+yf+W7mWolWFwFqaFOU19n1r Oc1aoqtZ1GbasWxGC1IkB6dV6xV9I9zMjDS2coFs3mbK3zXOXqAZ4v/ioaJp2NYW Ep7xd3pe1zaYFaUH6FxF2obwHo5KnlyjLWt9u9e+z7UMNH4mDgc7iz3t2LXhAo5K 59U= Received: (qmail 12821 invoked by alias); 9 Jun 2014 20:24:56 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 12686 invoked by uid 89); 9 Jun 2014 20:24:55 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-wi0-f171.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:content-type:content-transfer-encoding :subject:message-id:date:to:mime-version; bh=Ikm41bnKM4ONhdSziKdL9yaPnDcC/kXmrdzVwwFDqPQ=; b=EtWGJn6TccGgzpfeiy9rgv8p7rHlDZ8dsst6vCQmVSp7Q+Rsm0w9i8JnIrniKxv9+s c0fi/M2958sVcKLcyZN6rArRGcoppjecSYLCvwkdCpnyFH8sorZ5x25wtgNHNnYBxij9 JW+iI5f/YLcyTx/Q6Mu0gIux0cWedUxf26ICT+La3qnhoxn0fpTJpqg1H5D7z2csoJ6K TCmPCH6cqrPWt9FldhyYg3laeICYeZkrQZqxRF/dR6iiMNsRc0e7H2mISF/fcvMTjyv4 CLSCMy23UVxTpodT3ceK+Af7ZonvkEWKde6OuEhWPzjCTa5yCQqnjVY0zE99zYjNnP+n Y/BA== X-Gm-Message-State: ALoCoQkkjKyhl5Qj5PFZIjcMMqdX+5hu+2kGp6qeu8r7q146Ngg1Ik04vB4yjoCilEhRhmtxS4sP X-Received: by 10.180.83.40 with SMTP id n8mr410057wiy.41.1402345489861; Mon, 09 Jun 2014 13:24:49 -0700 (PDT) From: Bernard Ogden Subject: [PATCH 1/9][BZ 16892] Add linux-generic lowlevellock.h Message-Id: Date: Mon, 9 Jun 2014 21:24:46 +0100 To: libc-alpha@sourceware.org Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.2\)) Add linux-generic lowlevellock.h Based on tile's implementation, with a few changes: Use INTERNAL_SYSCALL_ERRNO to guarantee that error codes are positive, then negate it and return. Only applied to the three functions that actually inspect the error code beyond compare-to-zero. Prefer __glibc_unlikely to __builtin_expect, and atomic_compare_and_exchange_bool_acq to ..._val_acq where appropriate. Regards, Bernie 2014-06-09 Bernard Ogden [BZ #16892] * sysdeps/unix/sysv/linux/lowlevellock.h: New file. diff --git a/sysdeps/unix/sysv/linux/lowlevellock.h b/sysdeps/unix/sysv/linux/lowlevellock.h new file mode 100644 index 0000000..32f249d --- /dev/null +++ b/sysdeps/unix/sysv/linux/lowlevellock.h @@ -0,0 +1,335 @@ +/* Copyright (C) 2011-2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Chris Metcalf , 2011. + + 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 + . */ + +#ifndef _LOWLEVELLOCK_H +#define _LOWLEVELLOCK_H 1 + +#include +#include +#include +#include +#include +#include + + +#define FUTEX_WAIT 0 +#define FUTEX_WAKE 1 +#define FUTEX_REQUEUE 3 +#define FUTEX_CMP_REQUEUE 4 +#define FUTEX_WAKE_OP 5 +#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1) +#define FUTEX_LOCK_PI 6 +#define FUTEX_UNLOCK_PI 7 +#define FUTEX_TRYLOCK_PI 8 +#define FUTEX_WAIT_BITSET 9 +#define FUTEX_WAKE_BITSET 10 +#define FUTEX_WAIT_REQUEUE_PI 11 +#define FUTEX_CMP_REQUEUE_PI 12 +#define FUTEX_PRIVATE_FLAG 128 +#define FUTEX_CLOCK_REALTIME 256 + +#define FUTEX_BITSET_MATCH_ANY 0xffffffff + +/* Values for 'private' parameter of locking macros. Yes, the + definition seems to be backwards. But it is not. The bit will be + reversed before passing to the system call. */ +#define LLL_PRIVATE 0 +#define LLL_SHARED FUTEX_PRIVATE_FLAG + + +#if !defined NOT_IN_libc || defined IS_IN_rtld +/* In libc.so or ld.so all futexes are private. */ +# ifdef __ASSUME_PRIVATE_FUTEX +# define __lll_private_flag(fl, private) \ + ((fl) | FUTEX_PRIVATE_FLAG) +# else +# define __lll_private_flag(fl, private) \ + ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) +# endif +#else +# ifdef __ASSUME_PRIVATE_FUTEX +# define __lll_private_flag(fl, private) \ + (((fl) | FUTEX_PRIVATE_FLAG) ^ (private)) +# else +# define __lll_private_flag(fl, private) \ + (__builtin_constant_p (private) \ + ? ((private) == 0 \ + ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \ + : (fl)) \ + : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \ + & THREAD_GETMEM (THREAD_SELF, header.private_futex)))) +# endif +#endif + + +#define lll_futex_wait(futexp, val, private) \ + lll_futex_timed_wait (futexp, val, NULL, private) + +#define lll_futex_timed_wait(futexp, val, timespec, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \ + __lll_private_flag (FUTEX_WAIT, private), \ + (val), (timespec)); \ + if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \ + __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \ + __ret; \ + }) + +#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + int __op = FUTEX_WAIT_BITSET | clockbit; \ + \ + __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ + __lll_private_flag (__op, private), \ + (val), (timespec), NULL /* Unused. */, \ + FUTEX_BITSET_MATCH_ANY); \ + if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \ + __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \ + __ret; \ + }) + +#define lll_futex_wake(futexp, nr, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \ + __lll_private_flag (FUTEX_WAKE, private), \ + (nr), 0); \ + if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \ + __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \ + __ret; \ + }) + +#define lll_robust_dead(futexv, private) \ + do \ + { \ + int *__futexp = &(futexv); \ + atomic_or (__futexp, FUTEX_OWNER_DIED); \ + lll_futex_wake (__futexp, 1, private); \ + } \ + while (0) + +/* Returns non-zero if error happened, zero if success. */ +#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ + __lll_private_flag (FUTEX_CMP_REQUEUE, private),\ + (nr_wake), (nr_move), (mutex), (val)); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ + }) + +/* Returns non-zero if error happened, zero if success. */ +#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ + __lll_private_flag (FUTEX_WAKE_OP, private), \ + (nr_wake), (nr_wake2), (futexp2), \ + FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ + }) + +/* Priority Inheritance support. */ +#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \ + lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private) + +#define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \ + mutex, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \ + \ + __ret = INTERNAL_SYSCALL (futex, __err, 5, (futexp), \ + __lll_private_flag (__op, private), \ + (val), (timespec), mutex); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ + }) + +#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + \ + __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ + __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\ + (nr_wake), (nr_move), (mutex), (val)); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ + }) + + +static inline int __attribute__ ((always_inline)) +__lll_trylock (int *futex) +{ + return atomic_compare_and_exchange_bool_acq (futex, 1, 0); +} +#define lll_trylock(lock) __lll_trylock (&(lock)) + + +static inline int __attribute__ ((always_inline)) +__lll_cond_trylock (int *futex) +{ + return atomic_compare_and_exchange_bool_acq (futex, 2, 0); +} +#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock)) + + +static inline int __attribute__ ((always_inline)) +__lll_robust_trylock (int *futex, int id) +{ + return atomic_compare_and_exchange_bool_acq (futex, id, 0); +} +#define lll_robust_trylock(lock, id) \ + __lll_robust_trylock (&(lock), id) + +extern void __lll_lock_wait_private (int *futex) attribute_hidden; +extern void __lll_lock_wait (int *futex, int private) attribute_hidden; +extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden; + +static inline void __attribute__ ((always_inline)) +__lll_lock (int *futex, int private) +{ + if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0) + { + if (__builtin_constant_p (private) && private == LLL_PRIVATE) + __lll_lock_wait_private (futex); + else + __lll_lock_wait (futex, private); + } +} +#define lll_lock(futex, private) __lll_lock (&(futex), private) + + +static inline int __attribute__ ((always_inline)) +__lll_robust_lock (int *futex, int id, int private) +{ + int result = 0; + if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0) + result = __lll_robust_lock_wait (futex, private); + return result; +} +#define lll_robust_lock(futex, id, private) \ + __lll_robust_lock (&(futex), id, private) + + +static inline void __attribute__ ((always_inline)) +__lll_cond_lock (int *futex, int private) +{ + if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0) + __lll_lock_wait (futex, private); +} +#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private) + + +#define lll_robust_cond_lock(futex, id, private) \ + __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private) + + +extern int __lll_timedlock_wait (int *futex, const struct timespec *, + int private) attribute_hidden; +extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *, + int private) attribute_hidden; + +static inline int __attribute__ ((always_inline)) +__lll_timedlock (int *futex, const struct timespec *abstime, int private) +{ + int result = 0; + if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0) + result = __lll_timedlock_wait (futex, abstime, private); + return result; +} +#define lll_timedlock(futex, abstime, private) \ + __lll_timedlock (&(futex), abstime, private) + + +static inline int __attribute__ ((always_inline)) +__lll_robust_timedlock (int *futex, const struct timespec *abstime, + int id, int private) +{ + int result = 0; + if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0) + result = __lll_robust_timedlock_wait (futex, abstime, private); + return result; +} +#define lll_robust_timedlock(futex, abstime, id, private) \ + __lll_robust_timedlock (&(futex), abstime, id, private) + + +#define __lll_unlock(futex, private) \ + (void) \ + ({ int *__futex = (futex); \ + int __oldval = atomic_exchange_rel (__futex, 0); \ + if (__glibc_unlikely (__oldval > 1)) \ + lll_futex_wake (__futex, 1, private); \ + }) +#define lll_unlock(futex, private) __lll_unlock(&(futex), private) + + +#define __lll_robust_unlock(futex, private) \ + (void) \ + ({ int *__futex = (futex); \ + int __oldval = atomic_exchange_rel (__futex, 0); \ + if (__glibc_unlikely (__oldval & FUTEX_WAITERS)) \ + lll_futex_wake (__futex, 1, private); \ + }) +#define lll_robust_unlock(futex, private) \ + __lll_robust_unlock(&(futex), private) + + +#define lll_islocked(futex) \ + (futex != 0) + +/* Initializers for lock. */ +#define LLL_LOCK_INITIALIZER (0) +#define LLL_LOCK_INITIALIZER_LOCKED (1) + +/* The states of a lock are: + 0 - untaken + 1 - taken by one user + >1 - taken by more users */ + +/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex + wakeup when the clone terminates. The memory location contains the + thread ID while the clone is running and is reset to zero + afterwards. */ +#define lll_wait_tid(tid) \ + do { \ + __typeof (tid) __tid; \ + while ((__tid = (tid)) != 0) \ + lll_futex_wait (&(tid), __tid, LLL_SHARED); \ + } while (0) + +extern int __lll_timedwait_tid (int *, const struct timespec *) + attribute_hidden; + +#define lll_timedwait_tid(tid, abstime) \ + ({ \ + int __res = 0; \ + if ((tid) != 0) \ + __res = __lll_timedwait_tid (&(tid), (abstime)); \ + __res; \ + }) + +#endif /* lowlevellock.h */