diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S | 641 |
1 files changed, 641 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S b/sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S new file mode 100644 index 0000000000..94302b0641 --- /dev/null +++ b/sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S @@ -0,0 +1,641 @@ +/* Copyright (C) 2002-2016 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-errnos.h> +#include <pthread-pi-defines.h> +#include <kernel-features.h> +#include <stap-probe.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 + + pushl %ebp + cfi_adjust_cfa_offset(4) + cfi_rel_offset(%ebp, 0) + pushl %edi + cfi_adjust_cfa_offset(4) + cfi_rel_offset(%edi, 0) + pushl %esi + cfi_adjust_cfa_offset(4) + cfi_rel_offset(%esi, 0) + pushl %ebx + cfi_adjust_cfa_offset(4) + cfi_rel_offset(%ebx, 0) + + xorl %esi, %esi + movl 20(%esp), %ebx + + LIBC_PROBE (cond_wait, 2, 24(%esp), %ebx) + + /* Get internal lock. */ + movl $1, %edx + xorl %eax, %eax + LOCK +#if cond_lock == 0 + cmpxchgl %edx, (%ebx) +#else + cmpxchgl %edx, cond_lock(%ebx) +#endif + jnz 1f + + /* Store the reference to the mutex. If there is already a + different value in there this is a bad user bug. */ +2: cmpl $-1, dep_mutex(%ebx) + movl 24(%esp), %eax + je 15f + movl %eax, dep_mutex(%ebx) + + /* Unlock the mutex. */ +15: xorl %edx, %edx + call __pthread_mutex_unlock_usercnt + + testl %eax, %eax + jne 12f + + addl $1, total_seq(%ebx) + adcl $0, total_seq+4(%ebx) + addl $1, cond_futex(%ebx) + addl $(1 << nwaiters_shift), cond_nwaiters(%ebx) + +#define FRAME_SIZE 20 + subl $FRAME_SIZE, %esp + cfi_adjust_cfa_offset(FRAME_SIZE) + cfi_remember_state + + /* Get and store current wakeup_seq value. */ + movl wakeup_seq(%ebx), %edi + movl wakeup_seq+4(%ebx), %edx + movl broadcast_seq(%ebx), %eax + movl %edi, 4(%esp) + movl %edx, 8(%esp) + movl %eax, 12(%esp) + + /* Reset the pi-requeued flag. */ +8: movl $0, 16(%esp) + movl cond_futex(%ebx), %ebp + + /* Unlock. */ + LOCK +#if cond_lock == 0 + subl $1, (%ebx) +#else + subl $1, cond_lock(%ebx) +#endif + jne 3f + +.LcleanupSTART: +4: call __pthread_enable_asynccancel + movl %eax, (%esp) + + xorl %ecx, %ecx + cmpl $-1, dep_mutex(%ebx) + sete %cl + je 18f + + movl dep_mutex(%ebx), %edi + /* Requeue to a non-robust PI mutex if the PI bit is set and + the robust bit is not set. */ + movl MUTEX_KIND(%edi), %eax + andl $(ROBUST_BIT|PI_BIT), %eax + cmpl $PI_BIT, %eax + jne 18f + + movl $(FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %ecx + movl %ebp, %edx + xorl %esi, %esi + addl $cond_futex, %ebx +.Ladd_cond_futex_pi: + movl $SYS_futex, %eax + ENTER_KERNEL + subl $cond_futex, %ebx +.Lsub_cond_futex_pi: + /* Set the pi-requeued flag only if the kernel has returned 0. The + kernel does not hold the mutex on error. */ + cmpl $0, %eax + sete 16(%esp) + je 19f + + /* When a futex syscall with FUTEX_WAIT_REQUEUE_PI returns + successfully, it has already locked the mutex for us and the + pi_flag (16(%esp)) 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 19f + xorl %ecx, %ecx + +18: subl $1, %ecx +#ifdef __ASSUME_PRIVATE_FUTEX + andl $FUTEX_PRIVATE_FLAG, %ecx +#else + andl %gs:PRIVATE_FUTEX, %ecx +#endif +#if FUTEX_WAIT != 0 + addl $FUTEX_WAIT, %ecx +#endif + movl %ebp, %edx + addl $cond_futex, %ebx +.Ladd_cond_futex: + movl $SYS_futex, %eax + ENTER_KERNEL + subl $cond_futex, %ebx +.Lsub_cond_futex: + +19: movl (%esp), %eax + call __pthread_disable_asynccancel +.LcleanupEND: + + /* Lock. */ + movl $1, %edx + xorl %eax, %eax + LOCK +#if cond_lock == 0 + cmpxchgl %edx, (%ebx) +#else + cmpxchgl %edx, cond_lock(%ebx) +#endif + jnz 5f + +6: movl broadcast_seq(%ebx), %eax + cmpl 12(%esp), %eax + jne 16f + + movl woken_seq(%ebx), %eax + movl woken_seq+4(%ebx), %ecx + + movl wakeup_seq(%ebx), %edi + movl wakeup_seq+4(%ebx), %edx + + cmpl 8(%esp), %edx + jne 7f + cmpl 4(%esp), %edi + je 22f + +7: cmpl %ecx, %edx + jne 9f + cmp %eax, %edi + je 22f + +9: addl $1, woken_seq(%ebx) + adcl $0, woken_seq+4(%ebx) + + /* Unlock */ +16: subl $(1 << nwaiters_shift), cond_nwaiters(%ebx) + + /* Wake up a thread which wants to destroy the condvar object. */ + movl total_seq(%ebx), %eax + andl total_seq+4(%ebx), %eax + cmpl $0xffffffff, %eax + jne 17f + movl cond_nwaiters(%ebx), %eax + andl $~((1 << nwaiters_shift) - 1), %eax + jne 17f + + addl $cond_nwaiters, %ebx + movl $SYS_futex, %eax +#if FUTEX_PRIVATE_FLAG > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex-cond_nwaiters(%ebx) + sete %cl + subl $1, %ecx +#ifdef __ASSUME_PRIVATE_FUTEX + andl $FUTEX_PRIVATE_FLAG, %ecx +#else + andl %gs:PRIVATE_FUTEX, %ecx +#endif + addl $FUTEX_WAKE, %ecx + movl $1, %edx + ENTER_KERNEL + subl $cond_nwaiters, %ebx + +17: LOCK +#if cond_lock == 0 + subl $1, (%ebx) +#else + subl $1, cond_lock(%ebx) +#endif + jne 10f + + /* With requeue_pi, the mutex lock is held in the kernel. */ +11: movl 24+FRAME_SIZE(%esp), %eax + movl 16(%esp), %ecx + testl %ecx, %ecx + jnz 21f + + call __pthread_mutex_cond_lock +20: addl $FRAME_SIZE, %esp + cfi_adjust_cfa_offset(-FRAME_SIZE); + +14: popl %ebx + cfi_adjust_cfa_offset(-4) + cfi_restore(%ebx) + popl %esi + cfi_adjust_cfa_offset(-4) + cfi_restore(%esi) + popl %edi + cfi_adjust_cfa_offset(-4) + cfi_restore(%edi) + popl %ebp + cfi_adjust_cfa_offset(-4) + cfi_restore(%ebp) + + /* We return the result of the mutex_lock operation. */ + ret + + cfi_restore_state + +21: call __pthread_mutex_cond_lock_adjust + xorl %eax, %eax + jmp 20b + + cfi_adjust_cfa_offset(-FRAME_SIZE); + + /* We need to go back to futex_wait. If we're using requeue_pi, then + release the mutex we had acquired and go back. */ +22: movl 16(%esp), %edx + test %edx, %edx + 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. */ + movl dep_mutex(%ebx), %eax + call __pthread_mutex_cond_lock_adjust + xorl %edx, %edx + call __pthread_mutex_unlock_usercnt + jmp 8b + + /* Initial locking failed. */ +1: +#if cond_lock == 0 + movl %ebx, %edx +#else + leal cond_lock(%ebx), %edx +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_lock_wait + jmp 2b + + /* The initial unlocking of the mutex failed. */ +12: + LOCK +#if cond_lock == 0 + subl $1, (%ebx) +#else + subl $1, cond_lock(%ebx) +#endif + jne 14b + + movl %eax, %esi +#if cond_lock == 0 + movl %ebx, %eax +#else + leal cond_lock(%ebx), %eax +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_unlock_wake + + movl %esi, %eax + jmp 14b + + cfi_adjust_cfa_offset(FRAME_SIZE) + + /* Unlock in loop requires wakeup. */ +3: +#if cond_lock == 0 + movl %ebx, %eax +#else + leal cond_lock(%ebx), %eax +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_unlock_wake + jmp 4b + + /* Locking in loop failed. */ +5: +#if cond_lock == 0 + movl %ebx, %edx +#else + leal cond_lock(%ebx), %edx +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_lock_wait + jmp 6b + + /* Unlock after loop requires wakeup. */ +10: +#if cond_lock == 0 + movl %ebx, %eax +#else + leal cond_lock(%ebx), %eax +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_unlock_wake + jmp 11b + + .size __pthread_cond_wait, .-__pthread_cond_wait +versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait, + GLIBC_2_3_2) + + + .type __condvar_w_cleanup2, @function +__condvar_w_cleanup2: + subl $cond_futex, %ebx + .size __condvar_w_cleanup2, .-__condvar_w_cleanup2 +.LSbl4: + .type __condvar_w_cleanup, @function +__condvar_w_cleanup: + movl %eax, %esi + + /* Get internal lock. */ + movl $1, %edx + xorl %eax, %eax + LOCK +#if cond_lock == 0 + cmpxchgl %edx, (%ebx) +#else + cmpxchgl %edx, cond_lock(%ebx) +#endif + jz 1f + +#if cond_lock == 0 + movl %ebx, %edx +#else + leal cond_lock(%ebx), %edx +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_lock_wait + +1: movl broadcast_seq(%ebx), %eax + cmpl 12(%esp), %eax + 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. */ + movl total_seq(%ebx), %eax + movl total_seq+4(%ebx), %edi + cmpl wakeup_seq+4(%ebx), %edi + jb 6f + ja 7f + cmpl wakeup_seq(%ebx), %eax + jbe 7f + +6: addl $1, wakeup_seq(%ebx) + adcl $0, wakeup_seq+4(%ebx) + addl $1, cond_futex(%ebx) + +7: addl $1, woken_seq(%ebx) + adcl $0, woken_seq+4(%ebx) + +3: subl $(1 << nwaiters_shift), cond_nwaiters(%ebx) + + /* Wake up a thread which wants to destroy the condvar object. */ + xorl %edi, %edi + movl total_seq(%ebx), %eax + andl total_seq+4(%ebx), %eax + cmpl $0xffffffff, %eax + jne 4f + movl cond_nwaiters(%ebx), %eax + andl $~((1 << nwaiters_shift) - 1), %eax + jne 4f + + addl $cond_nwaiters, %ebx + movl $SYS_futex, %eax +#if FUTEX_PRIVATE_FLAG > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex-cond_nwaiters(%ebx) + sete %cl + subl $1, %ecx +#ifdef __ASSUME_PRIVATE_FUTEX + andl $FUTEX_PRIVATE_FLAG, %ecx +#else + andl %gs:PRIVATE_FUTEX, %ecx +#endif + addl $FUTEX_WAKE, %ecx + movl $1, %edx + ENTER_KERNEL + subl $cond_nwaiters, %ebx + movl $1, %edi + +4: LOCK +#if cond_lock == 0 + subl $1, (%ebx) +#else + subl $1, cond_lock(%ebx) +#endif + je 2f + +#if cond_lock == 0 + movl %ebx, %eax +#else + leal cond_lock(%ebx), %eax +#endif +#if (LLL_SHARED-LLL_PRIVATE) > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex(%ebx) + setne %cl + subl $1, %ecx + andl $(LLL_SHARED-LLL_PRIVATE), %ecx +#if LLL_PRIVATE != 0 + addl $LLL_PRIVATE, %ecx +#endif + call __lll_unlock_wake + + /* Wake up all waiters to make sure no signal gets lost. */ +2: testl %edi, %edi + jnz 5f + addl $cond_futex, %ebx +#if FUTEX_PRIVATE_FLAG > 255 + xorl %ecx, %ecx +#endif + cmpl $-1, dep_mutex-cond_futex(%ebx) + sete %cl + subl $1, %ecx +#ifdef __ASSUME_PRIVATE_FUTEX + andl $FUTEX_PRIVATE_FLAG, %ecx +#else + andl %gs:PRIVATE_FUTEX, %ecx +#endif + addl $FUTEX_WAKE, %ecx + movl $SYS_futex, %eax + movl $0x7fffffff, %edx + ENTER_KERNEL + + /* 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: movl 24+FRAME_SIZE(%esp), %eax + movl MUTEX_KIND(%eax), %ebx + andl $(ROBUST_BIT|PI_BIT), %ebx + cmpl $PI_BIT, %ebx + jne 8f + + movl (%eax), %ebx + andl $TID_MASK, %ebx + cmpl %ebx, %gs:TID + jne 8f + /* We managed to get the lock. Fix it up before returning. */ + call __pthread_mutex_cond_lock_adjust + jmp 9f + +8: call __pthread_mutex_cond_lock + +9: movl %esi, (%esp) +.LcallUR: + call _Unwind_Resume + hlt +.LENDCODE: + cfi_endproc + .size __condvar_w_cleanup, .-__condvar_w_cleanup + + + .section .gcc_except_table,"a",@progbits +.LexceptSTART: + .byte DW_EH_PE_omit # @LPStart format (omit) + .byte DW_EH_PE_omit # @TType format (omit) + .byte DW_EH_PE_sdata4 # call-site format + # DW_EH_PE_sdata4 + .uleb128 .Lcstend-.Lcstbegin +.Lcstbegin: + .long .LcleanupSTART-.LSTARTCODE + .long .Ladd_cond_futex_pi-.LcleanupSTART + .long __condvar_w_cleanup-.LSTARTCODE + .uleb128 0 + .long .Ladd_cond_futex_pi-.LSTARTCODE + .long .Lsub_cond_futex_pi-.Ladd_cond_futex_pi + .long __condvar_w_cleanup2-.LSTARTCODE + .uleb128 0 + .long .Lsub_cond_futex_pi-.LSTARTCODE + .long .Ladd_cond_futex-.Lsub_cond_futex_pi + .long __condvar_w_cleanup-.LSTARTCODE + .uleb128 0 + .long .Ladd_cond_futex-.LSTARTCODE + .long .Lsub_cond_futex-.Ladd_cond_futex + .long __condvar_w_cleanup2-.LSTARTCODE + .uleb128 0 + .long .Lsub_cond_futex-.LSTARTCODE + .long .LcleanupEND-.Lsub_cond_futex + .long __condvar_w_cleanup-.LSTARTCODE + .uleb128 0 + .long .LcallUR-.LSTARTCODE + .long .LENDCODE-.LcallUR + .long 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 4 + .type DW.ref.__gcc_personality_v0, @object + .size DW.ref.__gcc_personality_v0, 4 +DW.ref.__gcc_personality_v0: + .long __gcc_personality_v0 +#endif |