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Re: [PATCH 1/9][v3][BZ 16892] Add linux-generic lowlevellock.h
- From: Bernie Ogden <bernie dot ogden at linaro dot org>
- To: Andreas Schwab <schwab at linux-m68k dot org>
- Cc: Richard Henderson <rth at twiddle dot net>, libc-alpha <libc-alpha at sourceware dot org>
- Date: Mon, 23 Jun 2014 16:39:37 +0100
- Subject: Re: [PATCH 1/9][v3][BZ 16892] Add linux-generic lowlevellock.h
- Authentication-results: sourceware.org; auth=none
This patch had an OK before the coldfire problem came up. I believe
that's fixed, but anyway no platforms will be affected until they
delete their own implementation of lowlevellock.h.
Can we go ahead and commit this? If so, please could a committer do so?
Thanks,
Bernie
On 17 June 2014 20:17, Bernard Ogden <bernie.ogden@linaro.org> wrote:
> Darn.
>
> Converted inline functions to macros. Added some more __glibc_unlikely while I was in there.
>
> Still builds on arm. I did try to cross-build for coldfire but I failed - would you have any pointers for that?
>
> Anyway, should be fixed. OK?
>
>
> 2014-06-09 Bernard Ogden <bernie.ogden@linaro.org>
>
> [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..0cef90c
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/lowlevellock.h
> @@ -0,0 +1,308 @@
> +/* Copyright (C) 2011-2014 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> + Contributed by Chris Metcalf <cmetcalf@tilera.com>, 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
> + <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 INLINE_FUTEX_SYSCALL(nr, args...) \
> + ({ \
> + INTERNAL_SYSCALL_DECL (__err); \
> + long int __ret = INTERNAL_SYSCALL (futex, __err, nr, args); \
> + if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err))) \
> + __ret = -INTERNAL_SYSCALL_ERRNO (__ret, __err); \
> + __ret; \
> + })
> +
> +#define lll_futex_wait(futexp, val, private) \
> + lll_futex_timed_wait (futexp, val, NULL, private)
> +
> +#define lll_futex_timed_wait(futexp, val, timespec, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (4, (futexp), \
> + __lll_private_flag (FUTEX_WAIT, private), \
> + (val), (timespec)); \
> + })
> +
> +#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
> + ({ \
> + int __op = FUTEX_WAIT_BITSET | clockbit; \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (__op, private), \
> + (val), (timespec), NULL /* Unused. */, \
> + FUTEX_BITSET_MATCH_ANY); \
> + })
> +
> +#define lll_futex_wake(futexp, nr, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (4, (futexp), \
> + __lll_private_flag (FUTEX_WAKE, private), \
> + (nr), 0); \
> + })
> +
> +#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) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (FUTEX_CMP_REQUEUE, private), \
> + (nr_wake), (nr_move), (mutex), (val)); \
> + })
> +
> +/* Returns non-zero if error happened, zero if success. */
> +#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (FUTEX_WAKE_OP, private), \
> + (nr_wake), (nr_wake2), (futexp2), \
> + FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
> + })
> +
> +/* 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) \
> + ({ \
> + int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
> + INLINE_FUTEX_SYSCALL (5, (futexp), \
> + __lll_private_flag (__op, private), \
> + (val), (timespec), mutex); \
> + })
> +
> +#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv), \
> + (nr_wake), (nr_move), (mutex), (val)); \
> + })
> +
> +#define __lll_trylock(lock) \
> + atomic_compare_and_exchange_bool_acq (lock, 1, 0)
> +
> +#define lll_trylock(lock) __lll_trylock (&(lock))
> +
> +#define __lll_cond_trylock(lock) \
> + atomic_compare_and_exchange_bool_acq (lock, 2, 0)
> +
> +#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock))
> +
> +#define __lll_robust_trylock(lock, id) \
> + atomic_compare_and_exchange_bool_acq (lock, 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;
> +
> +#define __lll_lock(futex, private) \
> + (void) ({ \
> + int *__futex = (futex); \
> + if (__glibc_unlikely (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 (__glibc_unlikely (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)
> +
> +
> +#define __lll_cond_lock(futex, private) \
> + (void) ({ \
> + int *__futex = (futex); \
> + if (__glibc_unlikely (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;
> +
> +#define __lll_timedlock(futex, abstime, private) \
> + ({ \
> + int *__futex = (futex); \
> + int __val = 0; \
> + if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (__futex, 1, \
> + 0) != 0)) \
> + __val = __lll_timedlock_wait (__futex, abstime, private); \
> + __val; \
> + })
> +#define lll_timedlock(futex, abstime, private) \
> + __lll_timedlock (&(futex), abstime, private)
> +
> +
> +#define __lll_robust_timedlock(futex, abstime, id, private) \
> + ({ \
> + int *__futex = (futex); \
> + int __val = 0; \
> + if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (__futex, id, \
> + 0) != 0)) \
> + __val = __lll_robust_timedlock_wait (__futex, abstime, private); \
> + __val; \
> + })
> +#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 */
>
>
> On 14 Jun 2014, at 21:23, Andreas Schwab <schwab@linux-m68k.org> wrote:
>
>> Bernard Ogden <bernie.ogden@linaro.org> writes:
>>
>>> +static inline int __attribute__ ((always_inline))
>>> +__lll_trylock (int *futex)
>>> +{
>>> + return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
>>> +}
>>
>> You cannot use inlines here, it breaks coldfire:
>>
>> In file included from ../sysdeps/unix/sysv/linux/m68k/coldfire/sysdep.h:21:0,
>> from x.c:1:
>> ../sysdeps/unix/sysv/linux/lowlevellock.h: In function â__lll_trylockâ:
>> ../sysdeps/unix/sysdep.h:34:31: error: âSYS_atomic_cmpxchg_32â undeclared (first use in this function)
>> #define SYS_ify(syscall_name) SYS_##syscall_name
>> ^
>> ../sysdeps/unix/sysv/linux/m68k/coldfire/nptl/bits/atomic.h:74:29: note: in expansion of macro âSYS_ifyâ
>> = (__typeof (oldval)) SYS_ify (atomic_cmpxchg_32); \
>> ^
>> ../include/atomic.h:138:6: note: in expansion of macro âatomic_compare_and_exchange_val_acqâ
>> atomic_compare_and_exchange_val_acq (mem, newval, __atg3_old) \
>> ^
>> ../sysdeps/unix/sysv/linux/lowlevellock.h:186:10: note: in expansion of macro âatomic_compare_and_exchange_bool_acqâ
>> return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
>> ^
>> ../sysdeps/unix/sysdep.h:34:31: note: each undeclared identifier is reported only once for each function it appears in
>> #define SYS_ify(syscall_name) SYS_##syscall_name
>> ^
>> ../sysdeps/unix/sysv/linux/m68k/coldfire/nptl/bits/atomic.h:74:29: note: in expansion of macro âSYS_ifyâ
>> = (__typeof (oldval)) SYS_ify (atomic_cmpxchg_32); \
>> ^
>> ../include/atomic.h:138:6: note: in expansion of macro âatomic_compare_and_exchange_val_acqâ
>> atomic_compare_and_exchange_val_acq (mem, newval, __atg3_old) \
>> ^
>> ../sysdeps/unix/sysv/linux/lowlevellock.h:186:10: note: in expansion of macro âatomic_compare_and_exchange_bool_acqâ
>> return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
>> ^
>>
>> Andreas.
>>
>> --
>> Andreas Schwab, schwab@linux-m68k.org
>> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
>> "And now for something completely different."
>