nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S

   1 /* Copyright (C) 2009-2013 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20 #include <tcb-offsets.h>
  21 #include <kernel-features.h>
  22 #include "lowlevellock.h"
  23
  24 #ifdef IS_IN_libpthread
  25 # if defined SHARED && !defined NO_HIDDEN
  26 #  define __pthread_unwind __GI___pthread_unwind
  27 # endif
  28 #else
  29 # ifndef SHARED
  30         .weak __pthread_unwind
  31 # endif
  32 #endif
  33
  34
  35 #ifdef __ASSUME_PRIVATE_FUTEX
  36 # define LOAD_PRIVATE_FUTEX_WAIT(reg) \
  37         movl    $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
  38 #else
  39 # if FUTEX_WAIT == 0
  40 #  define LOAD_PRIVATE_FUTEX_WAIT(reg) \
  41         movl    %fs:PRIVATE_FUTEX, reg
  42 # else
  43 #  define LOAD_PRIVATE_FUTEX_WAIT(reg) \
  44         movl    %fs:PRIVATE_FUTEX, reg ; \
  45         orl     $FUTEX_WAIT, reg
  46 # endif
  47 #endif
  48
  49 /* It is crucial that the functions in this file don't modify registers
  50    other than %rax and %r11.  The syscall wrapper code depends on this
  51    because it doesn't explicitly save the other registers which hold
  52    relevant values.  */
  53         .text
  54
  55         .hidden __pthread_enable_asynccancel
  56 ENTRY(__pthread_enable_asynccancel)
  57         movl    %fs:CANCELHANDLING, %eax
  58 2:      movl    %eax, %r11d
  59         orl     $TCB_CANCELTYPE_BITMASK, %r11d
  60         cmpl    %eax, %r11d
  61         je      1f
  62
  63         lock
  64         cmpxchgl %r11d, %fs:CANCELHANDLING
  65         jnz     2b
  66
  67         andl    $(TCB_CANCELSTATE_BITMASK|TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK|TCB_EXITING_BITMASK|TCB_CANCEL_RESTMASK|TCB_TERMINATED_BITMASK), %r11d
  68         cmpl    $(TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK), %r11d
  69         je      3f
  70
  71 1:      ret
  72
  73 3:      subq    $8, %rsp
  74         cfi_adjust_cfa_offset(8)
  75         LP_OP(mov) $TCB_PTHREAD_CANCELED, %fs:RESULT
  76         lock
  77         orl     $TCB_EXITING_BITMASK, %fs:CANCELHANDLING
  78         mov     %fs:CLEANUP_JMP_BUF, %RDI_LP
  79 #ifdef SHARED
  80         call    __pthread_unwind@PLT
  81 #else
  82         call    __pthread_unwind
  83 #endif
  84         hlt
  85 END(__pthread_enable_asynccancel)
  86
  87
  88         .hidden __pthread_disable_asynccancel
  89 ENTRY(__pthread_disable_asynccancel)
  90         testl   $TCB_CANCELTYPE_BITMASK, %edi
  91         jnz     1f
  92
  93         movl    %fs:CANCELHANDLING, %eax
  94 2:      movl    %eax, %r11d
  95         andl    $~TCB_CANCELTYPE_BITMASK, %r11d
  96         lock
  97         cmpxchgl %r11d, %fs:CANCELHANDLING
  98         jnz     2b
  99
 100         movl    %r11d, %eax
 101 3:      andl    $(TCB_CANCELING_BITMASK|TCB_CANCELED_BITMASK), %eax
 102         cmpl    $TCB_CANCELING_BITMASK, %eax
 103         je      4f
 104 1:      ret
 105
 106         /* Performance doesn't matter in this loop.  We will
 107            delay until the thread is canceled.  And we will unlikely
 108            enter the loop twice.  */
 109 4:      mov     %fs:0, %RDI_LP
 110         movl    $__NR_futex, %eax
 111         xorq    %r10, %r10
 112         addq    $CANCELHANDLING, %rdi
 113         LOAD_PRIVATE_FUTEX_WAIT (%esi)
 114         syscall
 115         movl    %fs:CANCELHANDLING, %eax
 116         jmp     3b
 117 END(__pthread_disable_asynccancel)