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Re: [Ping][PATCH 9/9] MIPS - Remove mips lowlevellock.h
- From: Bernie Ogden <bernie dot ogden at linaro dot org>
- To: libc-alpha <libc-alpha at sourceware dot org>
- Date: Fri, 20 Jun 2014 11:28:41 +0100
- Subject: Re: [Ping][PATCH 9/9] MIPS - Remove mips lowlevellock.h
- Authentication-results: sourceware.org; auth=none
- References: <1A77677D-C7A9-426A-A607-2C69D565CE4A at linaro dot org>
Ping
On 9 June 2014 21:26, Bernard Ogden <bernie.ogden@linaro.org> wrote:
> Remove mips lowlevellock.h
>
> Results in following changes for mips:
>
> No longer casts futexp to long (4 instances of this)
>
> No longer inverts sign of syscall retval in
> lll_futex_timed_wait_pi. May have been a copy/paste error, the
> only caller just checks for zero.
>
> Neither built nor tested.
>
> Regards,
>
> Bernie
>
>
> 2014-06-09 Bernard Ogden <bernie.ogden@linaro.org>
>
> * sysdeps/unix/sysv/linux/mips/nptl/lowlevellock.h: Remove file.
>
> diff --git a/sysdeps/unix/sysv/linux/mips/nptl/lowlevellock.h b/sysdeps/unix/sysv/linux/mips/nptl/lowlevellock.h
> deleted file mode 100644
> index 07467f3..0000000
> --- a/sysdeps/unix/sysv/linux/mips/nptl/lowlevellock.h
> +++ /dev/null
> @@ -1,371 +0,0 @@
> -/* Copyright (C) 2003-2014 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 _LOWLEVELLOCK_H
> -#define _LOWLEVELLOCK_H 1
> -
> -#include <time.h>
> -#include <sys/param.h>
> -#include <bits/pthreadtypes.h>
> -#include <atomic.h>
> -#include <sysdep.h>
> -#include <kernel-features.h>
> -
> -#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, (long) (futexp), \
> - __lll_private_flag (FUTEX_WAIT, private), \
> - (val), (timespec)); \
> - INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __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, (long) (futexp), \
> - __lll_private_flag (__op, private), \
> - (val), (timespec), NULL /* Unused. */, \
> - FUTEX_BITSET_MATCH_ANY); \
> - INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
> - })
> -
> -#define lll_futex_wake(futexp, nr, private) \
> - ({ \
> - INTERNAL_SYSCALL_DECL (__err); \
> - long int __ret; \
> - __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \
> - __lll_private_flag (FUTEX_WAKE, private), \
> - (nr), 0); \
> - INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __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, (long) (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) ? -__ret : __ret; \
> - })
> -
> -#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_val_acq (futex, 1, 0) != 0;
> -}
> -#define lll_trylock(lock) __lll_trylock (&(lock))
> -
> -
> -static inline int __attribute__((always_inline))
> -__lll_cond_trylock(int *futex)
> -{
> - return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 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_val_acq (futex, id, 0) != 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;
> -
> -#define __lll_lock(futex, private) \
> - ((void) ({ \
> - int *__futex = (futex); \
> - if (__builtin_expect (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)
> -
> -
> -#define __lll_robust_lock(futex, id, private) \
> - ({ \
> - int *__futex = (futex); \
> - int __val = 0; \
> - \
> - if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
> - 0), 0)) \
> - __val = __lll_robust_lock_wait (__futex, private); \
> - __val; \
> - })
> -#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 __val = atomic_exchange_rel (__futex, 0); \
> - \
> - if (__builtin_expect (__val > 1, 0)) \
> - 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 __val = atomic_exchange_rel (__futex, 0); \
> - \
> - if (__builtin_expect (__val & FUTEX_WAITERS, 0)) \
> - lll_futex_wake (__futex, 1, private); \
> - }))
> -#define lll_robust_unlock(futex, private) \
> - __lll_robust_unlock(&(futex), private)
> -
> -
> -#define lll_islocked(futex) \
> - (futex != 0)
> -
> -
> -/* Our internal lock implementation is identical to the binary-compatible
> - mutex implementation. */
> -
> -/* 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; \
> - })
> -
> -/* Implement __libc_lock_lock using exchange_and_add, which expands into
> - a single instruction on XLP processors. We enable this for all MIPS
> - processors as atomic_exchange_and_add_acq and
> - atomic_compare_and_exchange_acq take the same time to execute.
> - This is a simplified expansion of ({ lll_lock (NAME, LLL_PRIVATE); 0; }).
> -
> - Note: __lll_lock_wait_private() resets lock value to '2', which prevents
> - unbounded increase of the lock value and [with billions of threads]
> - overflow. */
> -#define __libc_lock_lock(NAME) \
> - ({ \
> - int *__futex = &(NAME); \
> - if (__builtin_expect (atomic_exchange_and_add_acq (__futex, 1), 0)) \
> - __lll_lock_wait_private (__futex); \
> - 0; \
> - })
> -
> -#ifdef _MIPS_ARCH_XLP
> -/* The generic version using a single atomic_compare_and_exchange_acq takes
> - less time for non-XLP processors, so we use below for XLP only. */
> -# define __libc_lock_trylock(NAME) \
> - ({ \
> - int *__futex = &(NAME); \
> - int __result = atomic_exchange_and_add_acq (__futex, 1); \
> - /* If __result == 0, we succeeded in acquiring the lock. \
> - If __result == 1, we switched the lock to 'contended' state, which \
> - will cause a [possibly unnecessary] call to lll_futex_wait. This is \
> - unlikely, so we accept the possible inefficiency. \
> - If __result >= 2, we need to set the lock to 'contended' state to avoid \
> - unbounded increase from subsequent trylocks. */ \
> - if (__result >= 2) \
> - __result = atomic_exchange_acq (__futex, 2); \
> - __result; \
> - })
> -#endif
> -
> -#endif /* lowlevellock.h */
>