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glibc/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
Andi Kleen 1cdbe57948 Add the low level infrastructure for pthreads lock elision with TSX 
Lock elision using TSX is a technique to optimize lock scaling
It allows to run locks in parallel using hardware support for
a transactional execution mode in 4th generation Intel Core CPUs.
See http://www.intel.com/software/tsx for more Information.

This patch implements a simple adaptive lock elision algorithm based
on RTM. It enables elision for the pthread mutexes and rwlocks.
The algorithm keeps track whether a mutex successfully elides or not,
and stops eliding for some time when it is not.

When the CPU supports RTM the elision path is automatically tried,
otherwise any elision is disabled.

The adaptation algorithm and its tuning is currently preliminary.

The code adds some checks to the lock fast paths. Micro-benchmarks
show little to no difference without RTM.

This patch implements the low level "lll_" code for lock elision.
Followon patches hook this into the pthread implementation

Changes with the RTM mutexes:
-----------------------------
Lock elision in pthreads is generally compatible with existing programs.
There are some obscure exceptions, which are expected to be uncommon.
See the manual for more details.

- A broken program that unlocks a free lock will crash.
  There are ways around this with some tradeoffs (more code in hot paths)
  I'm still undecided on what approach to take here; have to wait for testing reports.
- pthread_mutex_destroy of a lock mutex will not return EBUSY but 0.
- There's also a similar situation with trylock outside the mutex,
  "knowing" that the mutex must be held due to some other condition.
  In this case an assert failure cannot be recovered. This situation is
  usually an existing bug in the program.
- Same applies to the rwlocks. Some of the return values changes
  (for example there is no EDEADLK for an elided lock, unless it aborts.
   However when elided it will also never deadlock of course)
- Timing changes, so broken programs that make assumptions about specific timing
  may expose already existing latent problems.  Note that these broken programs will
  break in other situations too (loaded system, new faster hardware, compiler
  optimizations etc.)
- Programs with non recursive mutexes that take them recursively in a thread and
  which would always deadlock without elision may not always see a deadlock.
  The deadlock will only happen on an early or delayed abort (which typically
  happens at some point)
  This only happens for mutexes not explicitely set to PTHREAD_MUTEX_NORMAL
  or PTHREAD_MUTEX_ADAPTIVE_NP.  PTHREAD_MUTEX_NORMAL mutexes do not elide.

The elision default can be set at configure time.

This patch implements the basic infrastructure for elision.
2013-07-02 08:46:54 -07:00

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/* Copyright (C) 2002-2013 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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 <stap-probe.h>
#ifndef __ASSEMBLER__
# include <time.h>
# include <sys/param.h>
# include <bits/pthreadtypes.h>
# include <kernel-features.h>
# include <tcb-offsets.h>
# ifndef LOCK_INSTR
# ifdef UP
# define LOCK_INSTR /* nothing */
# else
# define LOCK_INSTR "lock;"
# endif
# endif
#else
# ifndef LOCK
# ifdef UP
# define LOCK
# else
# define LOCK lock
# endif
# endif
#endif
#define SYS_futex __NR_futex
#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
#ifndef __ASSEMBLER__
#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)) \
: ({ unsigned int __fl = ((private) ^ FUTEX_PRIVATE_FLAG); \
asm ("andl %%fs:%P1, %0" : "+r" (__fl) \
: "i" (offsetof (struct pthread, header.private_futex))); \
__fl | (fl); }))
# endif
#endif
/* Initializer for lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
#define LLL_LOCK_INITIALIZER_WAITERS (2)
/* Delay in spinlock loop. */
#define BUSY_WAIT_NOP asm ("rep; nop")
#define LLL_STUB_UNWIND_INFO_START \
".section .eh_frame,\"a\",@progbits\n" \
"7:\t" ".long 9f-8f # Length of Common Information Entry\n" \
"8:\t" ".long 0x0 # CIE Identifier Tag\n\t" \
".byte 0x1 # CIE Version\n\t" \
".ascii \"zR\\0\" # CIE Augmentation\n\t" \
".uleb128 0x1 # CIE Code Alignment Factor\n\t" \
".sleb128 -8 # CIE Data Alignment Factor\n\t" \
".byte 0x10 # CIE RA Column\n\t" \
".uleb128 0x1 # Augmentation size\n\t" \
".byte 0x1b # FDE Encoding (pcrel sdata4)\n\t" \
".byte 0x12 # DW_CFA_def_cfa_sf\n\t" \
".uleb128 0x7\n\t" \
".sleb128 16\n\t" \
".align " LP_SIZE "\n" \
"9:\t" ".long 23f-10f # FDE Length\n" \
"10:\t" ".long 10b-7b # FDE CIE offset\n\t" \
".long 1b-. # FDE initial location\n\t" \
".long 6b-1b # FDE address range\n\t" \
".uleb128 0x0 # Augmentation size\n\t" \
".byte 0x16 # DW_CFA_val_expression\n\t" \
".uleb128 0x10\n\t" \
".uleb128 12f-11f\n" \
"11:\t" ".byte 0x80 # DW_OP_breg16\n\t" \
".sleb128 4b-1b\n"
#define LLL_STUB_UNWIND_INFO_END \
".byte 0x16 # DW_CFA_val_expression\n\t" \
".uleb128 0x10\n\t" \
".uleb128 14f-13f\n" \
"13:\t" ".byte 0x80 # DW_OP_breg16\n\t" \
".sleb128 4b-2b\n" \
"14:\t" ".byte 0x40 + (3b-2b) # DW_CFA_advance_loc\n\t" \
".byte 0x0e # DW_CFA_def_cfa_offset\n\t" \
".uleb128 0\n\t" \
".byte 0x16 # DW_CFA_val_expression\n\t" \
".uleb128 0x10\n\t" \
".uleb128 16f-15f\n" \
"15:\t" ".byte 0x80 # DW_OP_breg16\n\t" \
".sleb128 4b-3b\n" \
"16:\t" ".byte 0x40 + (4b-3b-1) # DW_CFA_advance_loc\n\t" \
".byte 0x0e # DW_CFA_def_cfa_offset\n\t" \
".uleb128 128\n\t" \
".byte 0x16 # DW_CFA_val_expression\n\t" \
".uleb128 0x10\n\t" \
".uleb128 20f-17f\n" \
"17:\t" ".byte 0x80 # DW_OP_breg16\n\t" \
".sleb128 19f-18f\n\t" \
".byte 0x0d # DW_OP_const4s\n" \
"18:\t" ".4byte 4b-.\n\t" \
".byte 0x1c # DW_OP_minus\n\t" \
".byte 0x0d # DW_OP_const4s\n" \
"19:\t" ".4byte 24f-.\n\t" \
".byte 0x22 # DW_OP_plus\n" \
"20:\t" ".byte 0x40 + (5b-4b+1) # DW_CFA_advance_loc\n\t" \
".byte 0x13 # DW_CFA_def_cfa_offset_sf\n\t" \
".sleb128 16\n\t" \
".byte 0x16 # DW_CFA_val_expression\n\t" \
".uleb128 0x10\n\t" \
".uleb128 22f-21f\n" \
"21:\t" ".byte 0x80 # DW_OP_breg16\n\t" \
".sleb128 4b-5b\n" \
"22:\t" ".align " LP_SIZE "\n" \
"23:\t" ".previous\n"
/* Unwind info for
1: leaq ..., %rdi
2: subq $128, %rsp
3: callq ...
4: addq $128, %rsp
5: jmp 24f
6:
snippet. */
#define LLL_STUB_UNWIND_INFO_5 \
LLL_STUB_UNWIND_INFO_START \
"12:\t" ".byte 0x40 + (2b-1b) # DW_CFA_advance_loc\n\t" \
LLL_STUB_UNWIND_INFO_END
/* Unwind info for
1: leaq ..., %rdi
0: movq ..., %rdx
2: subq $128, %rsp
3: callq ...
4: addq $128, %rsp
5: jmp 24f
6:
snippet. */
#define LLL_STUB_UNWIND_INFO_6 \
LLL_STUB_UNWIND_INFO_START \
"12:\t" ".byte 0x40 + (0b-1b) # DW_CFA_advance_loc\n\t" \
".byte 0x16 # DW_CFA_val_expression\n\t" \
".uleb128 0x10\n\t" \
".uleb128 26f-25f\n" \
"25:\t" ".byte 0x80 # DW_OP_breg16\n\t" \
".sleb128 4b-0b\n" \
"26:\t" ".byte 0x40 + (2b-0b) # DW_CFA_advance_loc\n\t" \
LLL_STUB_UNWIND_INFO_END
#define lll_futex_wait(futex, val, private) \
lll_futex_timed_wait(futex, val, NULL, private)
#define lll_futex_timed_wait(futex, val, timeout, private) \
({ \
register const struct timespec *__to __asm ("r10") = timeout; \
int __status; \
register __typeof (val) _val __asm ("edx") = (val); \
__asm __volatile ("syscall" \
: "=a" (__status) \
: "0" (SYS_futex), "D" (futex), \
"S" (__lll_private_flag (FUTEX_WAIT, private)), \
"d" (_val), "r" (__to) \
: "memory", "cc", "r11", "cx"); \
__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 ("syscall" \
: "=a" (__status) \
: "0" (SYS_futex), "D" (futex), \
"S" (__lll_private_flag (FUTEX_WAKE, private)), \
"d" (_nr) \
: "memory", "cc", "r10", "r11", "cx"); \
__status; \
})
/* NB: in the lll_trylock macro we simply return the value in %eax
after the cmpxchg instruction. In case the operation succeded this
value is zero. In case the operation failed, the cmpxchg instruction
has loaded the current value of the memory work which is guaranteed
to be nonzero. */
#if defined NOT_IN_libc || defined UP
# define __lll_trylock_asm LOCK_INSTR "cmpxchgl %2, %1"
#else
# define __lll_trylock_asm "cmpl $0, __libc_multiple_threads(%%rip)\n\t" \
"je 0f\n\t" \
"lock; cmpxchgl %2, %1\n\t" \
"jmp 1f\n\t" \
"0:\tcmpxchgl %2, %1\n\t" \
"1:"
#endif
#define lll_trylock(futex) \
({ int ret; \
__asm __volatile (__lll_trylock_asm \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_LOCK_INITIALIZER_LOCKED), "m" (futex), \
"0" (LLL_LOCK_INITIALIZER) \
: "memory"); \
ret; })
#define lll_robust_trylock(futex, id) \
({ int ret; \
__asm __volatile (LOCK_INSTR "cmpxchgl %2, %1" \
: "=a" (ret), "=m" (futex) \
: "r" (id), "m" (futex), "0" (LLL_LOCK_INITIALIZER) \
: "memory"); \
ret; })
#define lll_cond_trylock(futex) \
({ int ret; \
__asm __volatile (LOCK_INSTR "cmpxchgl %2, %1" \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_LOCK_INITIALIZER_WAITERS), \
"m" (futex), "0" (LLL_LOCK_INITIALIZER) \
: "memory"); \
ret; })
#if defined NOT_IN_libc || defined UP
# define __lll_lock_asm_start LOCK_INSTR "cmpxchgl %4, %2\n\t" \
"jnz 1f\n\t"
#else
# define __lll_lock_asm_start "cmpl $0, __libc_multiple_threads(%%rip)\n\t" \
"je 0f\n\t" \
"lock; cmpxchgl %4, %2\n\t" \
"jnz 1f\n\t" \
"jmp 24f\n" \
"0:\tcmpxchgl %4, %2\n\t" \
"jnz 1f\n\t"
#endif
#define lll_lock(futex, private) \
(void) \
({ int ignore1, ignore2, ignore3; \
if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
__asm __volatile (__lll_lock_asm_start \
".subsection 1\n\t" \
".type _L_lock_%=, @function\n" \
"_L_lock_%=:\n" \
"1:\tlea %2, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_lock_wait_private\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_lock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=S" (ignore1), "=&D" (ignore2), "=m" (futex), \
"=a" (ignore3) \
: "0" (1), "m" (futex), "3" (0) \
: "cx", "r11", "cc", "memory"); \
else \
__asm __volatile (__lll_lock_asm_start \
".subsection 1\n\t" \
".type _L_lock_%=, @function\n" \
"_L_lock_%=:\n" \
"1:\tlea %2, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_lock_wait\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_lock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=S" (ignore1), "=D" (ignore2), "=m" (futex), \
"=a" (ignore3) \
: "1" (1), "m" (futex), "3" (0), "0" (private) \
: "cx", "r11", "cc", "memory"); \
}) \
#define lll_robust_lock(futex, id, private) \
({ int result, ignore1, ignore2; \
__asm __volatile (LOCK_INSTR "cmpxchgl %4, %2\n\t" \
"jnz 1f\n\t" \
".subsection 1\n\t" \
".type _L_robust_lock_%=, @function\n" \
"_L_robust_lock_%=:\n" \
"1:\tlea %2, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_robust_lock_wait\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_robust_lock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=S" (ignore1), "=D" (ignore2), "=m" (futex), \
"=a" (result) \
: "1" (id), "m" (futex), "3" (0), "0" (private) \
: "cx", "r11", "cc", "memory"); \
result; })
#define lll_cond_lock(futex, private) \
(void) \
({ int ignore1, ignore2, ignore3; \
__asm __volatile (LOCK_INSTR "cmpxchgl %4, %2\n\t" \
"jnz 1f\n\t" \
".subsection 1\n\t" \
".type _L_cond_lock_%=, @function\n" \
"_L_cond_lock_%=:\n" \
"1:\tlea %2, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_lock_wait\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_cond_lock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=S" (ignore1), "=D" (ignore2), "=m" (futex), \
"=a" (ignore3) \
: "1" (2), "m" (futex), "3" (0), "0" (private) \
: "cx", "r11", "cc", "memory"); \
})
#define lll_robust_cond_lock(futex, id, private) \
({ int result, ignore1, ignore2; \
__asm __volatile (LOCK_INSTR "cmpxchgl %4, %2\n\t" \
"jnz 1f\n\t" \
".subsection 1\n\t" \
".type _L_robust_cond_lock_%=, @function\n" \
"_L_robust_cond_lock_%=:\n" \
"1:\tlea %2, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_robust_lock_wait\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_robust_cond_lock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=S" (ignore1), "=D" (ignore2), "=m" (futex), \
"=a" (result) \
: "1" (id | FUTEX_WAITERS), "m" (futex), "3" (0), \
"0" (private) \
: "cx", "r11", "cc", "memory"); \
result; })
#define lll_timedlock(futex, timeout, private) \
({ int result, ignore1, ignore2, ignore3; \
__asm __volatile (LOCK_INSTR "cmpxchgl %1, %4\n\t" \
"jnz 1f\n\t" \
".subsection 1\n\t" \
".type _L_timedlock_%=, @function\n" \
"_L_timedlock_%=:\n" \
"1:\tlea %4, %%" RDI_LP "\n" \
"0:\tmov %8, %%" RDX_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_timedlock_wait\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_timedlock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_6 \
"24:" \
: "=a" (result), "=D" (ignore1), "=S" (ignore2), \
"=&d" (ignore3), "=m" (futex) \
: "0" (0), "1" (1), "m" (futex), "m" (timeout), \
"2" (private) \
: "memory", "cx", "cc", "r10", "r11"); \
result; })
extern int __lll_timedlock_elision (int *futex, short *adapt_count,
const struct timespec *timeout,
int private) attribute_hidden;
#define lll_timedlock_elision(futex, adapt_count, timeout, private) \
__lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
#define lll_robust_timedlock(futex, timeout, id, private) \
({ int result, ignore1, ignore2, ignore3; \
__asm __volatile (LOCK_INSTR "cmpxchgl %1, %4\n\t" \
"jnz 1f\n\t" \
".subsection 1\n\t" \
".type _L_robust_timedlock_%=, @function\n" \
"_L_robust_timedlock_%=:\n" \
"1:\tlea %4, %%" RDI_LP "\n" \
"0:\tmov %8, %%" RDX_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_robust_timedlock_wait\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_robust_timedlock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_6 \
"24:" \
: "=a" (result), "=D" (ignore1), "=S" (ignore2), \
"=&d" (ignore3), "=m" (futex) \
: "0" (0), "1" (id), "m" (futex), "m" (timeout), \
"2" (private) \
: "memory", "cx", "cc", "r10", "r11"); \
result; })
#if defined NOT_IN_libc || defined UP
# define __lll_unlock_asm_start LOCK_INSTR "decl %0\n\t" \
"jne 1f\n\t"
#else
# define __lll_unlock_asm_start "cmpl $0, __libc_multiple_threads(%%rip)\n\t" \
"je 0f\n\t" \
"lock; decl %0\n\t" \
"jne 1f\n\t" \
"jmp 24f\n\t" \
"0:\tdecl %0\n\t" \
"jne 1f\n\t"
#endif
#define lll_unlock(futex, private) \
(void) \
({ int ignore; \
if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
__asm __volatile (__lll_unlock_asm_start \
".subsection 1\n\t" \
".type _L_unlock_%=, @function\n" \
"_L_unlock_%=:\n" \
"1:\tlea %0, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_unlock_wake_private\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_unlock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=m" (futex), "=&D" (ignore) \
: "m" (futex) \
: "ax", "cx", "r11", "cc", "memory"); \
else \
__asm __volatile (__lll_unlock_asm_start \
".subsection 1\n\t" \
".type _L_unlock_%=, @function\n" \
"_L_unlock_%=:\n" \
"1:\tlea %0, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_unlock_wake\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_unlock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=m" (futex), "=&D" (ignore) \
: "m" (futex), "S" (private) \
: "ax", "cx", "r11", "cc", "memory"); \
})
#define lll_robust_unlock(futex, private) \
do \
{ \
int ignore; \
__asm __volatile (LOCK_INSTR "andl %2, %0\n\t" \
"jne 1f\n\t" \
".subsection 1\n\t" \
".type _L_robust_unlock_%=, @function\n" \
"_L_robust_unlock_%=:\n" \
"1:\tlea %0, %%" RDI_LP "\n" \
"2:\tsub $128, %%" RSP_LP "\n" \
"3:\tcallq __lll_unlock_wake\n" \
"4:\tadd $128, %%" RSP_LP "\n" \
"5:\tjmp 24f\n" \
"6:\t.size _L_robust_unlock_%=, 6b-1b\n\t" \
".previous\n" \
LLL_STUB_UNWIND_INFO_5 \
"24:" \
: "=m" (futex), "=&D" (ignore) \
: "i" (FUTEX_WAITERS), "m" (futex), \
"S" (private) \
: "ax", "cx", "r11", "cc", "memory"); \
} \
while (0)
#define lll_robust_dead(futex, private) \
do \
{ \
int ignore; \
__asm __volatile (LOCK_INSTR "orl %3, (%2)\n\t" \
"syscall" \
: "=m" (futex), "=a" (ignore) \
: "D" (&(futex)), "i" (FUTEX_OWNER_DIED), \
"S" (__lll_private_flag (FUTEX_WAKE, private)), \
"1" (__NR_futex), "d" (1) \
: "cx", "r11", "cc", "memory"); \
} \
while (0)
/* Returns non-zero if error happened, zero if success. */
#define lll_futex_requeue(ftx, nr_wake, nr_move, mutex, val, private) \
({ int __res; \
register int __nr_move __asm ("r10") = nr_move; \
register void *__mutex __asm ("r8") = mutex; \
register int __val __asm ("r9") = val; \
__asm __volatile ("syscall" \
: "=a" (__res) \
: "0" (__NR_futex), "D" ((void *) ftx), \
"S" (__lll_private_flag (FUTEX_CMP_REQUEUE, \
private)), "d" (nr_wake), \
"r" (__nr_move), "r" (__mutex), "r" (__val) \
: "cx", "r11", "cc", "memory"); \
__res < 0; })
#define lll_islocked(futex) \
(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. */
#define lll_wait_tid(tid) \
do { \
int __ignore; \
register __typeof (tid) _tid asm ("edx") = (tid); \
if (_tid != 0) \
__asm __volatile ("xorq %%r10, %%r10\n\t" \
"1:\tmovq %2, %%rax\n\t" \
"syscall\n\t" \
"cmpl $0, (%%rdi)\n\t" \
"jne 1b" \
: "=&a" (__ignore) \
: "S" (FUTEX_WAIT), "i" (SYS_futex), "D" (&tid), \
"d" (_tid) \
: "memory", "cc", "r10", "r11", "cx"); \
} while (0)
extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
attribute_hidden;
#define lll_timedwait_tid(tid, abstime) \
({ \
int __result = 0; \
if (tid != 0) \
{ \
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) \
__result = EINVAL; \
else \
__result = __lll_timedwait_tid (&tid, abstime); \
} \
__result; })
extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
attribute_hidden;
extern int __lll_unlock_elision (int *lock, int private)
attribute_hidden;
extern int __lll_trylock_elision (int *lock, short *adapt_count)
attribute_hidden;
#define lll_lock_elision(futex, adapt_count, private) \
__lll_lock_elision (&(futex), &(adapt_count), private)
#define lll_unlock_elision(futex, private) \
__lll_unlock_elision (&(futex), private)
#define lll_trylock_elision(futex, adapt_count) \
__lll_trylock_elision (&(futex), &(adapt_count))
#endif /* !__ASSEMBLER__ */
#endif /* lowlevellock.h */
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