sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h

   1 /* Copyright (C) 2002-2016 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Jakub Jelinek <jakub@redhat.com>, 2002.
   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 <tls.h>
  21 #ifndef __ASSEMBLER__
  22 # include <nptl/pthreadP.h>
  23 #endif
  24
  25 #if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
  26
  27 /* The code to disable cancellation depends on the fact that the called
  28    functions are special.  They don't modify registers other than %rax
  29    and %r11 if they return.  Therefore we don't have to preserve other
  30    registers around these calls.  */
  31 # undef PSEUDO
  32 # define PSEUDO(name, syscall_name, args)                                     \
  33   .text;                                                                      \
  34   ENTRY (name)                                                                \
  35     SINGLE_THREAD_P;                                                          \
  36     jne L(pseudo_cancel);                                                     \
  37   .type __##syscall_name##_nocancel,@function;                                \
  38   .globl __##syscall_name##_nocancel;                                         \
  39   __##syscall_name##_nocancel:                                                \
  40     DO_CALL (syscall_name, args);                                             \
  41     cmpq $-4095, %rax;                                                        \
  42     jae SYSCALL_ERROR_LABEL;                                                  \
  43     ret;                                                                      \
  44   .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel;            \
  45   L(pseudo_cancel):                                                           \
  46     /* We always have to align the stack before calling a function.  */       \
  47     subq $8, %rsp; cfi_adjust_cfa_offset (8);                                 \
  48     CENABLE                                                                   \
  49     /* The return value from CENABLE is argument for CDISABLE.  */            \
  50     movq %rax, (%rsp);                                                        \
  51     DO_CALL (syscall_name, args);                                             \
  52     movq (%rsp), %rdi;                                                        \
  53     /* Save %rax since it's the error code from the syscall.  */              \
  54     movq %rax, %rdx;                                                          \
  55     CDISABLE                                                                  \
  56     movq %rdx, %rax;                                                          \
  57     addq $8,%rsp; cfi_adjust_cfa_offset (-8);                                 \
  58     cmpq $-4095, %rax;                                                        \
  59     jae SYSCALL_ERROR_LABEL
  60
  61
  62 # if IS_IN (libpthread)
  63 #  define CENABLE       call __pthread_enable_asynccancel;
  64 #  define CDISABLE      call __pthread_disable_asynccancel;
  65 #  define __local_multiple_threads __pthread_multiple_threads
  66 # elif IS_IN (libc)
  67 #  define CENABLE       call __libc_enable_asynccancel;
  68 #  define CDISABLE      call __libc_disable_asynccancel;
  69 #  define __local_multiple_threads __libc_multiple_threads
  70 # elif IS_IN (librt)
  71 #  define CENABLE       call __librt_enable_asynccancel;
  72 #  define CDISABLE      call __librt_disable_asynccancel;
  73 # else
  74 #  error Unsupported library
  75 # endif
  76
  77 # if IS_IN (libpthread) || IS_IN (libc)
  78 #  ifndef __ASSEMBLER__
  79 extern int __local_multiple_threads attribute_hidden;
  80 #   define SINGLE_THREAD_P \
  81   __builtin_expect (__local_multiple_threads == 0, 1)
  82 #  else
  83 #   define SINGLE_THREAD_P cmpl $0, __local_multiple_threads(%rip)
  84 #  endif
  85
  86 # else
  87
  88 #  ifndef __ASSEMBLER__
  89 #   define SINGLE_THREAD_P \
  90   __builtin_expect (THREAD_GETMEM (THREAD_SELF, \
  91                                    header.multiple_threads) == 0, 1)
  92 #  else
  93 #   define SINGLE_THREAD_P cmpl $0, %fs:MULTIPLE_THREADS_OFFSET
  94 #  endif
  95
  96 # endif
  97
  98 #elif !defined __ASSEMBLER__
  99
 100 # define SINGLE_THREAD_P (1)
 101 # define NO_CANCELLATION 1
 102
 103 #endif
 104
 105 #ifndef __ASSEMBLER__
 106 # define RTLD_SINGLE_THREAD_P \
 107   __builtin_expect (THREAD_GETMEM (THREAD_SELF, \
 108                                    header.multiple_threads) == 0, 1)
 109 #endif