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Optimize x86-64 syscall cancellation handling.
The syscall wrappers had to save and restore the syscall parameter values and return value when calling the functions to enable/disable cancellation were called. Not anymore. The called functions are special and don't modify any unexpected registers.
This commit is contained in:
Ulrich Drepper
parent
4a1377672c
commit
421665c40a
@ -1,3 +1,15 @@
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2009-08-04 Ulrich Drepper <drepper@redhat.com>
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* sysdeps/unix/sysv/linux/x86_64/cancellation.S: New file.
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* sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S: New file.
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* sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S: New file.
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* sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h (PSEUDO): Optimize
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since we can assume the special __*_{en,dis}able_asynccancel
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functions.
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(PUSHARGS_*, POPARGS_*, SAVESTK_*, RESTSTK_*): Removed.
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* sysdeps/x86_64/tcb-offsets.sym: Add cancellation-related bits
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and PTHREAD_CANCELED.
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2009-07-31 Ulrich Drepper <drepper@redhat.com>
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* descr.h: Better definition of *_BITMASK macros for cancellation.
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114
nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S
Normal file
114
nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S
Normal file
@ -0,0 +1,114 @@
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/* Copyright (C) 2009 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <sysdep.h>
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#include <tcb-offsets.h>
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#include <kernel-features.h>
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#ifdef IS_IN_libpthread
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# ifdef SHARED
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# define __pthread_unwind __GI___pthread_unwind
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# endif
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#else
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# ifndef SHARED
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.weak __pthread_unwind
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# endif
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#endif
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#ifdef __ASSUME_PRIVATE_FUTEX
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# define LOAD_PRIVATE_FUTEX_WAIT(reg) \
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movl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
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#else
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# if FUTEX_WAIT == 0
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# define LOAD_PRIVATE_FUTEX_WAIT(reg) \
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movl %fs:PRIVATE_FUTEX, reg
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# else
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# define LOAD_PRIVATE_FUTEX_WAIT(reg) \
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movl %fs:PRIVATE_FUTEX, reg ; \
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orl $FUTEX_WAIT, reg
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# endif
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#endif
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/* It is crucial that the functions in this file don't modify registers
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other than %rax and %r11. The syscall wrapper code depends on this
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because it doesn't explicitly save the other registers which hold
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relevant values. */
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.text
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.hidden __pthread_enable_asynccancel
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ENTRY(__pthread_enable_asynccancel)
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movl %fs:CANCELHANDLING, %eax
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2: movl %eax, %r11d
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orl $TCB_CANCELTYPE_BITMASK, %r11d
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cmpl %eax, %r11d
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je 1f
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lock
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cmpxchgl %r11d, %fs:CANCELHANDLING
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jnz 2b
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andl $(TCB_CANCELSTATE_BITMASK|TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK|TCB_EXITING_BITMASK|TCB_CANCEL_RESTMASK|TCB_TERMINATED_BITMASK), %r11d
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cmpl $(TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK), %r11d
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je 3f
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1: ret
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3: movq $TCB_PTHREAD_CANCELED, %fs:RESULT
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lock
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orl $TCB_EXITING_BITMASK, %fs:CANCELHANDLING
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movq %fs:CLEANUP_JMP_BUF, %rdi
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#ifdef SHARED
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call __pthread_unwind@PLT
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#else
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call __pthread_unwind
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#endif
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hlt
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END(__pthread_enable_asynccancel)
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.hidden __pthread_disable_asynccancel
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ENTRY(__pthread_disable_asynccancel)
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testl $TCB_CANCELTYPE_BITMASK, %edi
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jnz 1f
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movl %fs:CANCELHANDLING, %eax
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2: movl %eax, %r11d
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andl $~TCB_CANCELTYPE_BITMASK, %r11d
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lock
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cmpxchgl %r11d, %fs:CANCELHANDLING
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jnz 2b
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3: movl %r11d, %eax
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andl $(TCB_CANCELING_BITMASK|TCB_CANCELED_BITMASK), %eax
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cmpl $TCB_CANCELING_BITMASK, %eax
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je 4f
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1: ret
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/* Performance doesn't matter in this loop. We will
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delay until the thread is canceled. And we will unlikely
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enter the loop twice. */
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4: movq %fs:0, %rdi
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movl $__NR_futex, %eax
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xorq %r10, %r10
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addq $CANCELHANDLING, %rdi
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LOAD_PRIVATE_FUTEX_WAIT (%esi)
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syscall
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jmp 3b
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END(__pthread_disable_asynccancel)
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22
nptl/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
Normal file
22
nptl/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
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@ -0,0 +1,22 @@
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/* Copyright (C) 2009 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#define __pthread_enable_asynccancel __libc_enable_asynccancel
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#define __pthread_disable_asynccancel __libc_disable_asynccancel
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#include "cancellation.S"
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22
nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
Normal file
22
nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
Normal file
@ -0,0 +1,22 @@
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/* Copyright (C) 2009 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#define __pthread_enable_asynccancel __librt_enable_asynccancel
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#define __pthread_disable_asynccancel __librt_disable_asynccancel
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#include "cancellation.S"
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@ -1,4 +1,4 @@
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/* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
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/* Copyright (C) 2002-2006, 2009 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jakub Jelinek <jakub@redhat.com>, 2002.
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@ -25,6 +25,10 @@
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#if !defined NOT_IN_libc || defined IS_IN_libpthread || defined IS_IN_librt
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/* The code to disable cancellation depends on the fact that the called
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functions are special. They don't modify registers other than %rax
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and %r11 if they return. Therefore we don't have to preserve other
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registers around these calls. */
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# undef PSEUDO
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# define PSEUDO(name, syscall_name, args) \
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.text; \
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@ -40,60 +44,23 @@
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ret; \
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.size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
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L(pseudo_cancel): \
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/* Save registers that might get destroyed. */ \
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SAVESTK_##args \
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PUSHARGS_##args \
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/* We always have to align the stack before calling a function. */ \
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subq $8, %rsp; cfi_adjust_cfa_offset (8); \
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CENABLE \
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/* Restore registers. */ \
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POPARGS_##args \
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/* The return value from CENABLE is argument for CDISABLE. */ \
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movq %rax, (%rsp); \
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movl $SYS_ify (syscall_name), %eax; \
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syscall; \
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DO_CALL (syscall_name, args); \
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movq (%rsp), %rdi; \
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/* Save %rax since it's the error code from the syscall. */ \
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movq %rax, 8(%rsp); \
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movq %rax, %rdx; \
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CDISABLE \
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movq 8(%rsp), %rax; \
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RESTSTK_##args \
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movq %rdx, %rax; \
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addq $8,%rsp; cfi_adjust_cfa_offset (-8); \
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cmpq $-4095, %rax; \
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jae SYSCALL_ERROR_LABEL; \
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L(pseudo_end):
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# define PUSHARGS_0 /* Nothing. */
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# define PUSHARGS_1 PUSHARGS_0 movq %rdi, 8(%rsp);
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# define PUSHARGS_2 PUSHARGS_1 movq %rsi, 16(%rsp);
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# define PUSHARGS_3 PUSHARGS_2 movq %rdx, 24(%rsp);
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# define PUSHARGS_4 PUSHARGS_3 movq %rcx, 32(%rsp);
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# define PUSHARGS_5 PUSHARGS_4 movq %r8, 40(%rsp);
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# define PUSHARGS_6 PUSHARGS_5 movq %r9, 48(%rsp);
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# define POPARGS_0 /* Nothing. */
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# define POPARGS_1 POPARGS_0 movq 8(%rsp), %rdi;
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# define POPARGS_2 POPARGS_1 movq 16(%rsp), %rsi;
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# define POPARGS_3 POPARGS_2 movq 24(%rsp), %rdx;
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# define POPARGS_4 POPARGS_3 movq 32(%rsp), %r10;
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# define POPARGS_5 POPARGS_4 movq 40(%rsp), %r8;
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# define POPARGS_6 POPARGS_5 movq 48(%rsp), %r9;
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/* We always have to align the stack before calling a function. */
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# define SAVESTK_0 subq $24, %rsp; cfi_adjust_cfa_offset (24);
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# define SAVESTK_1 SAVESTK_0
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# define SAVESTK_2 SAVESTK_1
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# define SAVESTK_3 subq $40, %rsp; cfi_adjust_cfa_offset (40);
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# define SAVESTK_4 SAVESTK_3
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# define SAVESTK_5 subq $56, %rsp; cfi_adjust_cfa_offset (56);
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# define SAVESTK_6 SAVESTK_5
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# define RESTSTK_0 addq $24,%rsp; cfi_adjust_cfa_offset (-24);
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# define RESTSTK_1 RESTSTK_0
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# define RESTSTK_2 RESTSTK_1
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# define RESTSTK_3 addq $40, %rsp; cfi_adjust_cfa_offset (-40);
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# define RESTSTK_4 RESTSTK_3
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# define RESTSTK_5 addq $56, %rsp; cfi_adjust_cfa_offset (-56);
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# define RESTSTK_6 RESTSTK_5
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# ifdef IS_IN_libpthread
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# define CENABLE call __pthread_enable_asynccancel;
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# define CDISABLE call __pthread_disable_asynccancel;
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@ -16,3 +16,13 @@ VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
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PRIVATE_FUTEX offsetof (tcbhead_t, private_futex)
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#endif
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RTLD_SAVESPACE_SSE offsetof (tcbhead_t, rtld_savespace_sse)
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-- Not strictly offsets, but these values are also used in the TCB.
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TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
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TCB_CANCELTYPE_BITMASK CANCELTYPE_BITMASK
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TCB_CANCELING_BITMASK CANCELING_BITMASK
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TCB_CANCELED_BITMASK CANCELED_BITMASK
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TCB_EXITING_BITMASK EXITING_BITMASK
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TCB_CANCEL_RESTMASK CANCEL_RESTMASK
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TCB_TERMINATED_BITMASK TERMINATED_BITMASK
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TCB_PTHREAD_CANCELED PTHREAD_CANCELED
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