--- /dev/null
+/* Low-level locking access to futex facilities. Linux/i386 version.
+ Copyright (C) 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_FUTEX_H
+#define _LOWLEVELLOCK_FUTEX_H 1
+
+#define FUTEX_WAIT 0
+#define FUTEX_WAKE 1
+#define FUTEX_CMP_REQUEUE 4
+#define FUTEX_WAKE_OP 5
+#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
+
+#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
+
+/* 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 IS_IN (libc) || 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)) \
+ : ({ unsigned int __fl = ((private) ^ FUTEX_PRIVATE_FLAG); \
+ asm ("andl %%gs:%P1, %0" : "+r" (__fl) \
+ : "i" (offsetof (struct pthread, header.private_futex))); \
+ __fl | (fl); }))
+# endif
+#endif
+
+
+#ifndef __ASSEMBLER__
+
+/* To avoid naming conflicts with lowlevellock.h, use a different prefix
+ here. */
+#ifdef PIC
+# define LLLF_EBX_LOAD "xchgl %2, %%ebx\n"
+# define LLLF_EBX_REG "D"
+#else
+# define LLLF_EBX_LOAD
+# define LLLF_EBX_REG "b"
+#endif
+
+#ifdef I386_USE_SYSENTER
+# ifdef SHARED
+# define LLLF_ENTER_KERNEL "call *%%gs:%P6\n\t"
+# else
+# define LLLF_ENTER_KERNEL "call *_dl_sysinfo\n\t"
+# endif
+#else
+# define LLLF_ENTER_KERNEL "int $0x80\n\t"
+#endif
+
+
+#define lll_futex_wait(futex, val, private) \
+ lll_futex_timed_wait (futex, val, NULL, private)
+
+
+#define lll_futex_timed_wait(futex, val, timeout, private) \
+ ({ \
+ int __status; \
+ register __typeof (val) _val asm ("edx") = (val); \
+ __asm __volatile (LLLF_EBX_LOAD \
+ LLLF_ENTER_KERNEL \
+ LLLF_EBX_LOAD \
+ : "=a" (__status) \
+ : "0" (SYS_futex), LLLF_EBX_REG (futex), "S" (timeout), \
+ "c" (__lll_private_flag (FUTEX_WAIT, private)), \
+ "d" (_val), "i" (offsetof (tcbhead_t, sysinfo)) \
+ : "memory"); \
+ __status; \
+ })
+
+
+#define lll_futex_wake(futex, nr, private) \
+ ({ \
+ int __status; \
+ register __typeof (nr) _nr asm ("edx") = (nr); \
+ LIBC_PROBE (lll_futex_wake, 3, futex, nr, private); \
+ __asm __volatile (LLLF_EBX_LOAD \
+ LLLF_ENTER_KERNEL \
+ LLLF_EBX_LOAD \
+ : "=a" (__status) \
+ : "0" (SYS_futex), LLLF_EBX_REG (futex), \
+ "c" (__lll_private_flag (FUTEX_WAKE, private)), \
+ "d" (_nr), \
+ "i" (0) /* phony, to align next arg's number */, \
+ "i" (offsetof (tcbhead_t, sysinfo))); \
+ __status; \
+ })
+
+
+#endif /* !__ASSEMBLER__ */
+
+#endif /* lowlevellock-futex.h */
# endif
#endif
+#include <lowlevellock-futex.h>
+
+/* XXX Remove when no assembler code uses futexes anymore. */
#define SYS_futex 240
-#define FUTEX_WAIT 0
-#define FUTEX_WAKE 1
-#define FUTEX_CMP_REQUEUE 4
-#define FUTEX_WAKE_OP 5
-#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
-
-#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
-
-/* 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 IS_IN (libc) || 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)) \
- : ({ unsigned int __fl = ((private) ^ FUTEX_PRIVATE_FLAG); \
- asm ("andl %%gs:%P1, %0" : "+r" (__fl) \
- : "i" (offsetof (struct pthread, header.private_futex))); \
- __fl | (fl); }))
-# endif
-#endif
#ifndef __ASSEMBLER__
/* Delay in spinlock loop. */
#define BUSY_WAIT_NOP asm ("rep; nop")
-#define lll_futex_wait(futex, val, private) \
- lll_futex_timed_wait (futex, val, NULL, private)
-
-
-#define lll_futex_timed_wait(futex, val, timeout, private) \
- ({ \
- int __status; \
- register __typeof (val) _val asm ("edx") = (val); \
- __asm __volatile (LLL_EBX_LOAD \
- LLL_ENTER_KERNEL \
- LLL_EBX_LOAD \
- : "=a" (__status) \
- : "0" (SYS_futex), LLL_EBX_REG (futex), "S" (timeout), \
- "c" (__lll_private_flag (FUTEX_WAIT, private)), \
- "d" (_val), "i" (offsetof (tcbhead_t, sysinfo)) \
- : "memory"); \
- __status; \
- })
-
-
-#define lll_futex_wake(futex, nr, private) \
- ({ \
- int __status; \
- register __typeof (nr) _nr asm ("edx") = (nr); \
- LIBC_PROBE (lll_futex_wake, 3, futex, nr, private); \
- __asm __volatile (LLL_EBX_LOAD \
- LLL_ENTER_KERNEL \
- LLL_EBX_LOAD \
- : "=a" (__status) \
- : "0" (SYS_futex), LLL_EBX_REG (futex), \
- "c" (__lll_private_flag (FUTEX_WAKE, private)), \
- "d" (_nr), \
- "i" (0) /* phony, to align next arg's number */, \
- "i" (offsetof (tcbhead_t, sysinfo))); \
- __status; \
- })
-
/* NB: in the lll_trylock macro we simply return the value in %eax
after the cmpxchg instruction. In case the operation succeded this
(futex != LLL_LOCK_INITIALIZER)
/* 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.
-
- The macro parameter must not have any side effect. */
+ wake-up when the clone terminates. The memory location contains the
+ thread ID while the clone is running and is reset to zero by the kernel
+ afterwards. The kernel up to version 3.16.3 does not use the private futex
+ operations for futex wake-up when the clone terminates. */
#define lll_wait_tid(tid) \
- do { \
- int __ignore; \
- register __typeof (tid) _tid asm ("edx") = (tid); \
- if (_tid != 0) \
- __asm __volatile (LLL_EBX_LOAD \
- "1:\tmovl %1, %%eax\n\t" \
- LLL_ENTER_KERNEL \
- "cmpl $0, (%%ebx)\n\t" \
- "jne 1b\n\t" \
- LLL_EBX_LOAD \
- : "=&a" (__ignore) \
- : "i" (SYS_futex), LLL_EBX_REG (&tid), "S" (0), \
- "c" (FUTEX_WAIT), "d" (_tid), \
- "i" (offsetof (tcbhead_t, sysinfo)) \
- : "memory"); \
+ do { \
+ __typeof (tid) __tid; \
+ while ((__tid = (tid)) != 0) \
+ lll_futex_wait (&(tid), __tid, LLL_SHARED);\
} while (0)
extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
__attribute__ ((regparm (2))) attribute_hidden;
+
+/* As lll_wait_tid, but with a timeout. If the timeout occurs then return
+ ETIMEDOUT. If ABSTIME is invalid, return EINVAL.
+ XXX Note that this differs from the generic version in that we do the
+ error checking here and not in __lll_timedwait_tid. */
#define lll_timedwait_tid(tid, abstime) \
({ \
int __result = 0; \
- if (tid != 0) \
+ if ((tid) != 0) \
{ \
- if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) \
+ if ((abstime)->tv_nsec < 0 || (abstime)->tv_nsec >= 1000000000) \
__result = EINVAL; \
else \
- __result = __lll_timedwait_tid (&tid, abstime); \
+ __result = __lll_timedwait_tid (&(tid), (abstime)); \
} \
__result; })
+
extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
attribute_hidden;
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