| /* Copyright (C) 2002-2014 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/>. */ |
| |
| #include <sysdep.h> |
| #include <shlib-compat.h> |
| #include <lowlevellock.h> |
| #include <lowlevelcond.h> |
| #include <tcb-offsets.h> |
| #include <pthread-pi-defines.h> |
| #include <pthread-errnos.h> |
| #include <stap-probe.h> |
| |
| #include <kernel-features.h> |
| |
| |
| .text |
| |
| /* int pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex) */ |
| .globl __pthread_cond_wait |
| .type __pthread_cond_wait, @function |
| .align 16 |
| __pthread_cond_wait: |
| .LSTARTCODE: |
| cfi_startproc |
| #ifdef SHARED |
| cfi_personality(DW_EH_PE_pcrel | DW_EH_PE_sdata4 | DW_EH_PE_indirect, |
| DW.ref.__gcc_personality_v0) |
| cfi_lsda(DW_EH_PE_pcrel | DW_EH_PE_sdata4, .LexceptSTART) |
| #else |
| cfi_personality(DW_EH_PE_udata4, __gcc_personality_v0) |
| cfi_lsda(DW_EH_PE_udata4, .LexceptSTART) |
| #endif |
| |
| #define FRAME_SIZE (32+8) |
| leaq -FRAME_SIZE(%rsp), %rsp |
| cfi_adjust_cfa_offset(FRAME_SIZE) |
| |
| /* Stack frame: |
| |
| rsp + 32 |
| +--------------------------+ |
| rsp + 24 | old wake_seq value | |
| +--------------------------+ |
| rsp + 16 | mutex pointer | |
| +--------------------------+ |
| rsp + 8 | condvar pointer | |
| +--------------------------+ |
| rsp + 4 | old broadcast_seq value | |
| +--------------------------+ |
| rsp + 0 | old cancellation mode | |
| +--------------------------+ |
| */ |
| |
| LIBC_PROBE (cond_wait, 2, %rdi, %rsi) |
| |
| LP_OP(cmp) $-1, dep_mutex(%rdi) |
| |
| /* Prepare structure passed to cancellation handler. */ |
| movq %rdi, 8(%rsp) |
| movq %rsi, 16(%rsp) |
| |
| je 15f |
| mov %RSI_LP, dep_mutex(%rdi) |
| |
| /* Get internal lock. */ |
| 15: movl $1, %esi |
| xorl %eax, %eax |
| LOCK |
| #if cond_lock == 0 |
| cmpxchgl %esi, (%rdi) |
| #else |
| cmpxchgl %esi, cond_lock(%rdi) |
| #endif |
| jne 1f |
| |
| /* Unlock the mutex. */ |
| 2: movq 16(%rsp), %rdi |
| xorl %esi, %esi |
| callq __pthread_mutex_unlock_usercnt |
| |
| testl %eax, %eax |
| jne 12f |
| |
| movq 8(%rsp), %rdi |
| incq total_seq(%rdi) |
| incl cond_futex(%rdi) |
| addl $(1 << nwaiters_shift), cond_nwaiters(%rdi) |
| |
| /* Get and store current wakeup_seq value. */ |
| movq 8(%rsp), %rdi |
| movq wakeup_seq(%rdi), %r9 |
| movl broadcast_seq(%rdi), %edx |
| movq %r9, 24(%rsp) |
| movl %edx, 4(%rsp) |
| |
| /* Unlock. */ |
| 8: movl cond_futex(%rdi), %edx |
| LOCK |
| #if cond_lock == 0 |
| decl (%rdi) |
| #else |
| decl cond_lock(%rdi) |
| #endif |
| jne 3f |
| |
| .LcleanupSTART: |
| 4: callq __pthread_enable_asynccancel |
| movl %eax, (%rsp) |
| |
| xorq %r10, %r10 |
| LP_OP(cmp) $-1, dep_mutex(%rdi) |
| leaq cond_futex(%rdi), %rdi |
| movl $FUTEX_WAIT, %esi |
| je 60f |
| |
| mov dep_mutex-cond_futex(%rdi), %R8_LP |
| /* Requeue to a non-robust PI mutex if the PI bit is set and |
| the robust bit is not set. */ |
| movl MUTEX_KIND(%r8), %eax |
| andl $(ROBUST_BIT|PI_BIT), %eax |
| cmpl $PI_BIT, %eax |
| jne 61f |
| |
| movl $(FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %esi |
| movl $SYS_futex, %eax |
| syscall |
| |
| cmpl $0, %eax |
| sete %r8b |
| |
| #ifdef __ASSUME_REQUEUE_PI |
| jmp 62f |
| #else |
| je 62f |
| |
| /* When a futex syscall with FUTEX_WAIT_REQUEUE_PI returns |
| successfully, it has already locked the mutex for us and the |
| pi_flag (%r8b) is set to denote that fact. However, if another |
| thread changed the futex value before we entered the wait, the |
| syscall may return an EAGAIN and the mutex is not locked. We go |
| ahead with a success anyway since later we look at the pi_flag to |
| decide if we got the mutex or not. The sequence numbers then make |
| sure that only one of the threads actually wake up. We retry using |
| normal FUTEX_WAIT only if the kernel returned ENOSYS, since normal |
| and PI futexes don't mix. |
| |
| Note that we don't check for EAGAIN specifically; we assume that the |
| only other error the futex function could return is EAGAIN since |
| anything else would mean an error in our function. It is too |
| expensive to do that check for every call (which is quite common in |
| case of a large number of threads), so it has been skipped. */ |
| cmpl $-ENOSYS, %eax |
| jne 62f |
| |
| # ifndef __ASSUME_PRIVATE_FUTEX |
| movl $FUTEX_WAIT, %esi |
| # endif |
| #endif |
| |
| 61: |
| #ifdef __ASSUME_PRIVATE_FUTEX |
| movl $(FUTEX_WAIT|FUTEX_PRIVATE_FLAG), %esi |
| #else |
| orl %fs:PRIVATE_FUTEX, %esi |
| #endif |
| 60: xorb %r8b, %r8b |
| movl $SYS_futex, %eax |
| syscall |
| |
| 62: movl (%rsp), %edi |
| callq __pthread_disable_asynccancel |
| .LcleanupEND: |
| |
| /* Lock. */ |
| movq 8(%rsp), %rdi |
| movl $1, %esi |
| xorl %eax, %eax |
| LOCK |
| #if cond_lock == 0 |
| cmpxchgl %esi, (%rdi) |
| #else |
| cmpxchgl %esi, cond_lock(%rdi) |
| #endif |
| jnz 5f |
| |
| 6: movl broadcast_seq(%rdi), %edx |
| |
| movq woken_seq(%rdi), %rax |
| |
| movq wakeup_seq(%rdi), %r9 |
| |
| cmpl 4(%rsp), %edx |
| jne 16f |
| |
| cmpq 24(%rsp), %r9 |
| jbe 19f |
| |
| cmpq %rax, %r9 |
| jna 19f |
| |
| incq woken_seq(%rdi) |
| |
| /* Unlock */ |
| 16: subl $(1 << nwaiters_shift), cond_nwaiters(%rdi) |
| |
| /* Wake up a thread which wants to destroy the condvar object. */ |
| cmpq $0xffffffffffffffff, total_seq(%rdi) |
| jne 17f |
| movl cond_nwaiters(%rdi), %eax |
| andl $~((1 << nwaiters_shift) - 1), %eax |
| jne 17f |
| |
| addq $cond_nwaiters, %rdi |
| LP_OP(cmp) $-1, dep_mutex-cond_nwaiters(%rdi) |
| movl $1, %edx |
| #ifdef __ASSUME_PRIVATE_FUTEX |
| movl $FUTEX_WAKE, %eax |
| movl $(FUTEX_WAKE|FUTEX_PRIVATE_FLAG), %esi |
| cmove %eax, %esi |
| #else |
| movl $0, %eax |
| movl %fs:PRIVATE_FUTEX, %esi |
| cmove %eax, %esi |
| orl $FUTEX_WAKE, %esi |
| #endif |
| movl $SYS_futex, %eax |
| syscall |
| subq $cond_nwaiters, %rdi |
| |
| 17: LOCK |
| #if cond_lock == 0 |
| decl (%rdi) |
| #else |
| decl cond_lock(%rdi) |
| #endif |
| jne 10f |
| |
| /* If requeue_pi is used the kernel performs the locking of the |
| mutex. */ |
| 11: movq 16(%rsp), %rdi |
| testb %r8b, %r8b |
| jnz 18f |
| |
| callq __pthread_mutex_cond_lock |
| |
| 14: leaq FRAME_SIZE(%rsp), %rsp |
| cfi_adjust_cfa_offset(-FRAME_SIZE) |
| |
| /* We return the result of the mutex_lock operation. */ |
| retq |
| |
| cfi_adjust_cfa_offset(FRAME_SIZE) |
| |
| 18: callq __pthread_mutex_cond_lock_adjust |
| xorl %eax, %eax |
| jmp 14b |
| |
| /* We need to go back to futex_wait. If we're using requeue_pi, then |
| release the mutex we had acquired and go back. */ |
| 19: testb %r8b, %r8b |
| jz 8b |
| |
| /* Adjust the mutex values first and then unlock it. The unlock |
| should always succeed or else the kernel did not lock the mutex |
| correctly. */ |
| movq 16(%rsp), %rdi |
| callq __pthread_mutex_cond_lock_adjust |
| movq %rdi, %r8 |
| xorl %esi, %esi |
| callq __pthread_mutex_unlock_usercnt |
| /* Reload cond_var. */ |
| movq 8(%rsp), %rdi |
| jmp 8b |
| |
| /* Initial locking failed. */ |
| 1: |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| callq __lll_lock_wait |
| jmp 2b |
| |
| /* Unlock in loop requires wakeup. */ |
| 3: |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| /* The call preserves %rdx. */ |
| callq __lll_unlock_wake |
| #if cond_lock != 0 |
| subq $cond_lock, %rdi |
| #endif |
| jmp 4b |
| |
| /* Locking in loop failed. */ |
| 5: |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| callq __lll_lock_wait |
| #if cond_lock != 0 |
| subq $cond_lock, %rdi |
| #endif |
| jmp 6b |
| |
| /* Unlock after loop requires wakeup. */ |
| 10: |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| callq __lll_unlock_wake |
| jmp 11b |
| |
| /* The initial unlocking of the mutex failed. */ |
| 12: movq %rax, %r10 |
| movq 8(%rsp), %rdi |
| LOCK |
| #if cond_lock == 0 |
| decl (%rdi) |
| #else |
| decl cond_lock(%rdi) |
| #endif |
| je 13f |
| |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| callq __lll_unlock_wake |
| |
| 13: movq %r10, %rax |
| jmp 14b |
| |
| .size __pthread_cond_wait, .-__pthread_cond_wait |
| versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait, |
| GLIBC_2_3_2) |
| |
| |
| .align 16 |
| .type __condvar_cleanup1, @function |
| .globl __condvar_cleanup1 |
| .hidden __condvar_cleanup1 |
| __condvar_cleanup1: |
| /* Stack frame: |
| |
| rsp + 32 |
| +--------------------------+ |
| rsp + 24 | unused | |
| +--------------------------+ |
| rsp + 16 | mutex pointer | |
| +--------------------------+ |
| rsp + 8 | condvar pointer | |
| +--------------------------+ |
| rsp + 4 | old broadcast_seq value | |
| +--------------------------+ |
| rsp + 0 | old cancellation mode | |
| +--------------------------+ |
| */ |
| |
| movq %rax, 24(%rsp) |
| |
| /* Get internal lock. */ |
| movq 8(%rsp), %rdi |
| movl $1, %esi |
| xorl %eax, %eax |
| LOCK |
| #if cond_lock == 0 |
| cmpxchgl %esi, (%rdi) |
| #else |
| cmpxchgl %esi, cond_lock(%rdi) |
| #endif |
| jz 1f |
| |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| callq __lll_lock_wait |
| #if cond_lock != 0 |
| subq $cond_lock, %rdi |
| #endif |
| |
| 1: movl broadcast_seq(%rdi), %edx |
| cmpl 4(%rsp), %edx |
| jne 3f |
| |
| /* We increment the wakeup_seq counter only if it is lower than |
| total_seq. If this is not the case the thread was woken and |
| then canceled. In this case we ignore the signal. */ |
| movq total_seq(%rdi), %rax |
| cmpq wakeup_seq(%rdi), %rax |
| jbe 6f |
| incq wakeup_seq(%rdi) |
| incl cond_futex(%rdi) |
| 6: incq woken_seq(%rdi) |
| |
| 3: subl $(1 << nwaiters_shift), cond_nwaiters(%rdi) |
| |
| /* Wake up a thread which wants to destroy the condvar object. */ |
| xorl %ecx, %ecx |
| cmpq $0xffffffffffffffff, total_seq(%rdi) |
| jne 4f |
| movl cond_nwaiters(%rdi), %eax |
| andl $~((1 << nwaiters_shift) - 1), %eax |
| jne 4f |
| |
| LP_OP(cmp) $-1, dep_mutex(%rdi) |
| leaq cond_nwaiters(%rdi), %rdi |
| movl $1, %edx |
| #ifdef __ASSUME_PRIVATE_FUTEX |
| movl $FUTEX_WAKE, %eax |
| movl $(FUTEX_WAKE|FUTEX_PRIVATE_FLAG), %esi |
| cmove %eax, %esi |
| #else |
| movl $0, %eax |
| movl %fs:PRIVATE_FUTEX, %esi |
| cmove %eax, %esi |
| orl $FUTEX_WAKE, %esi |
| #endif |
| movl $SYS_futex, %eax |
| syscall |
| subq $cond_nwaiters, %rdi |
| movl $1, %ecx |
| |
| 4: LOCK |
| #if cond_lock == 0 |
| decl (%rdi) |
| #else |
| decl cond_lock(%rdi) |
| #endif |
| je 2f |
| #if cond_lock != 0 |
| addq $cond_lock, %rdi |
| #endif |
| LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi) |
| movl $LLL_PRIVATE, %eax |
| movl $LLL_SHARED, %esi |
| cmovne %eax, %esi |
| /* The call preserves %rcx. */ |
| callq __lll_unlock_wake |
| |
| /* Wake up all waiters to make sure no signal gets lost. */ |
| 2: testl %ecx, %ecx |
| jnz 5f |
| addq $cond_futex, %rdi |
| LP_OP(cmp) $-1, dep_mutex-cond_futex(%rdi) |
| movl $0x7fffffff, %edx |
| #ifdef __ASSUME_PRIVATE_FUTEX |
| movl $FUTEX_WAKE, %eax |
| movl $(FUTEX_WAKE|FUTEX_PRIVATE_FLAG), %esi |
| cmove %eax, %esi |
| #else |
| movl $0, %eax |
| movl %fs:PRIVATE_FUTEX, %esi |
| cmove %eax, %esi |
| orl $FUTEX_WAKE, %esi |
| #endif |
| movl $SYS_futex, %eax |
| syscall |
| |
| /* Lock the mutex only if we don't own it already. This only happens |
| in case of PI mutexes, if we got cancelled after a successful |
| return of the futex syscall and before disabling async |
| cancellation. */ |
| 5: movq 16(%rsp), %rdi |
| movl MUTEX_KIND(%rdi), %eax |
| andl $(ROBUST_BIT|PI_BIT), %eax |
| cmpl $PI_BIT, %eax |
| jne 7f |
| |
| movl (%rdi), %eax |
| andl $TID_MASK, %eax |
| cmpl %eax, %fs:TID |
| jne 7f |
| /* We managed to get the lock. Fix it up before returning. */ |
| callq __pthread_mutex_cond_lock_adjust |
| jmp 8f |
| |
| |
| 7: callq __pthread_mutex_cond_lock |
| |
| 8: movq 24(%rsp), %rdi |
| .LcallUR: |
| call _Unwind_Resume@PLT |
| hlt |
| .LENDCODE: |
| cfi_endproc |
| .size __condvar_cleanup1, .-__condvar_cleanup1 |
| |
| |
| .section .gcc_except_table,"a",@progbits |
| .LexceptSTART: |
| .byte DW_EH_PE_omit # @LPStart format |
| .byte DW_EH_PE_omit # @TType format |
| .byte DW_EH_PE_uleb128 # call-site format |
| .uleb128 .Lcstend-.Lcstbegin |
| .Lcstbegin: |
| .uleb128 .LcleanupSTART-.LSTARTCODE |
| .uleb128 .LcleanupEND-.LcleanupSTART |
| .uleb128 __condvar_cleanup1-.LSTARTCODE |
| .uleb128 0 |
| .uleb128 .LcallUR-.LSTARTCODE |
| .uleb128 .LENDCODE-.LcallUR |
| .uleb128 0 |
| .uleb128 0 |
| .Lcstend: |
| |
| |
| #ifdef SHARED |
| .hidden DW.ref.__gcc_personality_v0 |
| .weak DW.ref.__gcc_personality_v0 |
| .section .gnu.linkonce.d.DW.ref.__gcc_personality_v0,"aw",@progbits |
| .align LP_SIZE |
| .type DW.ref.__gcc_personality_v0, @object |
| .size DW.ref.__gcc_personality_v0, LP_SIZE |
| DW.ref.__gcc_personality_v0: |
| ASM_ADDR __gcc_personality_v0 |
| #endif |