x86_64/pthreads/pthread_mutex_lock.s

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <machine/cpu_capabilities.h>
  25
  26 #define PTHRW_LVAL    0
  27 #define PTHRW_UVAL    4
  28
  29         .text
  30         .align  2
  31         .globl  __commpage_pthread_mutex_lock
  32 __commpage_pthread_mutex_lock:
  33         pushq   %rbp                // set up frame for backtrace
  34         movq    %rsp,%rbp
  35         pushq   %rbx
  36         xorl    %ebx,%ebx           // clear "preemption pending" flag
  37         movl    $(_COMM_PAGE_SPIN_COUNT), %eax
  38 1:
  39         testl   PTHRW_LVAL(%rdi),%ecx // is mutex available?
  40         jz      2f                  // yes, it is available
  41         pause
  42         decl    %eax                // decrement max spin count
  43         jnz     1b                  // keep spinning
  44 2:
  45         movq    $(_COMM_PAGE_PFZ_MUTEX_LOCK), %rcx
  46         call    *%rcx
  47         testl   %ebx,%ebx           // pending preemption?
  48         jz      1f                  // no
  49         call    _preempt
  50 1:
  51         popq    %rbx
  52         popq    %rbp
  53         ret