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nptl: Assume __ASSUME_FUTEX_CLOCK_REALTIME support

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This patch assumes realtime clock support for nptl and thus removes
all the associated code.

For __pthread_mutex_timedlock the fallback usage for the case where
lll_futex_timed_wait_bitset it not set define is also removed. The
generic lowlevellock-futex.h always define it, so for NPTL code the
check always yield true.

Checked on x86_64-linux-gnu and i686-linux-gnu.

	* nptl/nptl-init.c (__have_futex_clock_realtime,
	__have_futex_clock_realtime): Remove definition.
	(__pthread_initialize_minimal_internal): Remove FUTEX_CLOCK_REALTIME
	check test for !__ASSUME_FUTEX_CLOCK_REALTIME.
	* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock): Assume
	__ASSUME_FUTEX_CLOCK_REALTIME support.
	* sysdeps/unix/sysv/linux/i386/lowlevellock.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise.
	* sysdeps/unix/sysv/linux/kernel-features.h
	(__ASSUME_FUTEX_CLOCK_REALTIME): Remove.
	* sysdeps/nptl/lowlevellock-futex.h (lll_futex_timed_wait_bitset):
	Adjust comment.
This commit is contained in:
Adhemerval Zanella 2019-02-28 11:33:22 -03:00
parent 590675c079
commit 0ddb7ea842
7 changed files with 16 additions and 276 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
ChangeLog
View File

@ -1,3 +1,18 @@
2019-03-05 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl/nptl-init.c (__have_futex_clock_realtime,
__have_futex_clock_realtime): Remove definition.
(__pthread_initialize_minimal_internal): Remove FUTEX_CLOCK_REALTIME
check test for !__ASSUME_FUTEX_CLOCK_REALTIME.
* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock): Assume
__ASSUME_FUTEX_CLOCK_REALTIME support.
* sysdeps/unix/sysv/linux/i386/lowlevellock.S: Likewise.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise.
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_FUTEX_CLOCK_REALTIME): Remove.
* sysdeps/nptl/lowlevellock-futex.h (lll_futex_timed_wait_bitset):
Adjust comment.
2019-03-05 Gabriel F. T. Gomes <gabriel@inconstante.eti.br>
* sysdeps/powerpc/powerpc64/power6/wcscpy.c (WCSCPY): Define to

29
nptl/nptl-init.c
View File

@ -58,15 +58,6 @@ int __set_robust_list_avail;
# define set_robust_list_not_avail() do { } while (0)
#endif
#ifndef __ASSUME_FUTEX_CLOCK_REALTIME
/* Nonzero if we do not have FUTEX_CLOCK_REALTIME. */
int __have_futex_clock_realtime;
# define __set_futex_clock_realtime() \
__have_futex_clock_realtime = 1
#else
#define __set_futex_clock_realtime() do { } while (0)
#endif
/* Version of the library, used in libthread_db to detect mismatches. */
static const char nptl_version[] __attribute_used__ = VERSION;
@ -298,26 +289,6 @@ __pthread_initialize_minimal_internal (void)
set_robust_list_not_avail ();
}
#ifdef __NR_futex
# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
{
int word = 0;
/* NB: the syscall actually takes six parameters. The last is the
bit mask. But since we will not actually wait at all the value
is irrelevant. Given that passing six parameters is difficult
on some architectures we just pass whatever random value the
calling convention calls for to the kernel. It causes no harm. */
INTERNAL_SYSCALL_DECL (err);
word = INTERNAL_SYSCALL (futex, err, 5, &word,
FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME
| FUTEX_PRIVATE_FLAG, 1, NULL, 0);
assert (INTERNAL_SYSCALL_ERROR_P (word, err));
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.
It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
purposes this is good enough. */

27
nptl/pthread_mutex_timedlock.c
View File

@ -240,27 +240,6 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
values despite them being valid. */
if (__glibc_unlikely (abstime->tv_sec < 0))
return ETIMEDOUT;
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|| !defined lll_futex_timed_wait_bitset)
struct timeval tv;
struct timespec rt;
/* Get the current time. */
(void) __gettimeofday (&tv, NULL);
/* Compute relative timeout. */
rt.tv_sec = abstime->tv_sec - tv.tv_sec;
rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
if (rt.tv_nsec < 0)
{
rt.tv_nsec += 1000000000;
--rt.tv_sec;
}
/* Already timed out? */
if (rt.tv_sec < 0)
return ETIMEDOUT;
#endif
/* We cannot acquire the mutex nor has its owner died. Thus, try
to block using futexes. Set FUTEX_WAITERS if necessary so that
@ -287,18 +266,12 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
assume_other_futex_waiters |= FUTEX_WAITERS;
/* Block using the futex. */
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|| !defined lll_futex_timed_wait_bitset)
lll_futex_timed_wait (&mutex->__data.__lock, oldval,
&rt, PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
#else
int err = lll_futex_timed_wait_bitset (&mutex->__data.__lock,
oldval, abstime, FUTEX_CLOCK_REALTIME,
PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
/* The futex call timed out. */
if (err == -ETIMEDOUT)
return -err;
#endif
/* Reload current lock value. */
oldval = mutex->__data.__lock;
}

3
sysdeps/nptl/lowlevellock-futex.h
View File

@ -43,8 +43,7 @@
#define lll_futex_timed_wait(futexp, val, timeout, private) \
-ENOSYS
/* This macro should be defined only if FUTEX_CLOCK_REALTIME is also defined.
If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
/* If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
TIMEOUT is counted by CLOCK_REALTIME rather than CLOCK_MONOTONIC. */
#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \

100
sysdeps/unix/sysv/linux/i386/lowlevellock.S
View File

@ -148,16 +148,6 @@ __lll_timedlock_wait:
cfi_adjust_cfa_offset(4)
cfi_rel_offset(%ebx, 0)
# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
# ifdef PIC
LOAD_PIC_REG (bx)
cmpl $0, __have_futex_clock_realtime@GOTOFF(%ebx)
# else
cmpl $0, __have_futex_clock_realtime
# endif
je .Lreltmo
# endif
cmpl $0, (%edx)
js 8f
@ -199,96 +189,6 @@ __lll_timedlock_wait:
8: movl $ETIMEDOUT, %eax
jmp 7b
# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
.Lreltmo:
/* Check for a valid timeout value. */
cmpl $1000000000, 4(%edx)
jae 3f
pushl %esi
cfi_adjust_cfa_offset(4)
cfi_rel_offset(%esi, 0)
pushl %edi
cfi_adjust_cfa_offset(4)
cfi_rel_offset(%edi, 0)
/* Stack frame for the timespec and timeval structs. */
subl $8, %esp
cfi_adjust_cfa_offset(8)
movl %ecx, %ebp
movl %edx, %edi
movl $2, %edx
xchgl %edx, (%ebp)
test %edx, %edx
je 6f
1:
/* Get current time. */
movl %esp, %ebx
xorl %ecx, %ecx
movl $__NR_gettimeofday, %eax
ENTER_KERNEL
/* Compute relative timeout. */
movl 4(%esp), %eax
movl $1000, %edx
mul %edx /* Milli seconds to nano seconds. */
movl (%edi), %ecx
movl 4(%edi), %edx
subl (%esp), %ecx
subl %eax, %edx
jns 4f
addl $1000000000, %edx
subl $1, %ecx
4: testl %ecx, %ecx
js 2f /* Time is already up. */
/* Store relative timeout. */
movl %ecx, (%esp)
movl %edx, 4(%esp)
/* Futex call. */
movl %ebp, %ebx
movl $2, %edx
movl %esp, %esi
movl 16(%esp), %ecx
LOAD_FUTEX_WAIT (%ecx)
movl $SYS_futex, %eax
ENTER_KERNEL
/* NB: %edx == 2 */
xchgl %edx, (%ebp)
testl %edx, %edx
je 6f
cmpl $-ETIMEDOUT, %eax
jne 1b
2: movl $ETIMEDOUT, %edx
6: addl $8, %esp
cfi_adjust_cfa_offset(-8)
popl %edi
cfi_adjust_cfa_offset(-4)
cfi_restore(%edi)
popl %esi
cfi_adjust_cfa_offset(-4)
cfi_restore(%esi)
7: popl %ebx
cfi_adjust_cfa_offset(-4)
cfi_restore(%ebx)
popl %ebp
cfi_adjust_cfa_offset(-4)
cfi_restore(%ebp)
movl %edx, %eax
ret
3: movl $EINVAL, %edx
jmp 7b
# endif
cfi_endproc
.size __lll_timedlock_wait,.-__lll_timedlock_wait
#endif

3
sysdeps/unix/sysv/linux/kernel-features.h
View File

@ -57,9 +57,6 @@
2.6.27. */
#define __ASSUME_IN_NONBLOCK 1
/* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29. */
#define __ASSUME_FUTEX_CLOCK_REALTIME 1
/* Support for preadv and pwritev was added in 2.6.30. */
#define __ASSUME_PREADV 1
#define __ASSUME_PWRITEV 1

115
sysdeps/unix/sysv/linux/x86_64/lowlevellock.S
View File

@ -127,15 +127,6 @@ __lll_lock_wait:
.align 16
__lll_timedlock_wait:
cfi_startproc
# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
# ifdef PIC
cmpl $0, __have_futex_clock_realtime(%rip)
# else
cmpl $0, __have_futex_clock_realtime
# endif
je .Lreltmo
# endif
cmpq $0, (%rdx)
js 5f
@ -176,112 +167,6 @@ __lll_timedlock_wait:
5: movl $ETIMEDOUT, %eax
retq
# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
.Lreltmo:
/* Check for a valid timeout value. */
cmpq $1000000000, 8(%rdx)
jae 3f
pushq %r8
cfi_adjust_cfa_offset(8)
pushq %r9
cfi_adjust_cfa_offset(8)
pushq %r12
cfi_adjust_cfa_offset(8)
pushq %r13
cfi_adjust_cfa_offset(8)
pushq %r14
cfi_adjust_cfa_offset(8)
cfi_offset(%r8, -16)
cfi_offset(%r9, -24)
cfi_offset(%r12, -32)
cfi_offset(%r13, -40)
cfi_offset(%r14, -48)
pushq %rsi
cfi_adjust_cfa_offset(8)
/* Stack frame for the timespec and timeval structs. */
subq $24, %rsp
cfi_adjust_cfa_offset(24)
movq %rdi, %r12
movq %rdx, %r13
movl $2, %edx
xchgl %edx, (%r12)
testl %edx, %edx
je 6f
1:
/* Get current time. */
movq %rsp, %rdi
xorl %esi, %esi
/* This call works because we directly jump to a system call entry
which preserves all the registers. */
call JUMPTARGET(__gettimeofday)
/* Compute relative timeout. */
movq 8(%rsp), %rax
movl $1000, %edi
mul %rdi /* Milli seconds to nano seconds. */
movq (%r13), %rdi
movq 8(%r13), %rsi
subq (%rsp), %rdi
subq %rax, %rsi
jns 4f
addq $1000000000, %rsi
decq %rdi
4: testq %rdi, %rdi
js 2f /* Time is already up. */
/* Store relative timeout. */
movq %rdi, (%rsp)
movq %rsi, 8(%rsp)
/* Futex call. */
movl $2, %edx
movl $1, %eax
movq %rsp, %r10
movl 24(%rsp), %esi
LOAD_FUTEX_WAIT (%esi)
movq %r12, %rdi
movl $SYS_futex, %eax
syscall
/* NB: %edx == 2 */
xchgl %edx, (%r12)
testl %edx, %edx
je 6f
cmpl $-ETIMEDOUT, %eax
jne 1b
2: movl $ETIMEDOUT, %edx
6: addq $32, %rsp
cfi_adjust_cfa_offset(-32)
popq %r14
cfi_adjust_cfa_offset(-8)
cfi_restore(%r14)
popq %r13
cfi_adjust_cfa_offset(-8)
cfi_restore(%r13)
popq %r12
cfi_adjust_cfa_offset(-8)
cfi_restore(%r12)
popq %r9
cfi_adjust_cfa_offset(-8)
cfi_restore(%r9)
popq %r8
cfi_adjust_cfa_offset(-8)
cfi_restore(%r8)
movl %edx, %eax
retq
3: movl $EINVAL, %eax
retq
# endif
cfi_endproc
.size __lll_timedlock_wait,.-__lll_timedlock_wait
#endif