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Re: [PING][PATCH 1/9][v3][BZ 16892] Add linux-generic lowlevellock.h


Ping. I think this qualifies as OK (see my last comment, below). Can we commit?

On 23 June 2014 16:39, Bernie Ogden <bernie.ogden@linaro.org> wrote:
> 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."
>>


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