1/* Copyright (C) 2009-2019 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#define PTHREAD_UNWIND JUMPTARGET(__pthread_unwind)
25#if IS_IN (libpthread)
26# if defined SHARED && !defined NO_HIDDEN
27# undef PTHREAD_UNWIND
28# define PTHREAD_UNWIND __GI___pthread_unwind
29# endif
30#else
31# ifndef SHARED
32 .weak __pthread_unwind
33# endif
34#endif
35
36
37#define LOAD_PRIVATE_FUTEX_WAIT(reg) \
38 movl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
39
40/* It is crucial that the functions in this file don't modify registers
41 other than %rax and %r11. The syscall wrapper code depends on this
42 because it doesn't explicitly save the other registers which hold
43 relevant values. */
44 .text
45
46 .hidden __pthread_enable_asynccancel
47ENTRY(__pthread_enable_asynccancel)
48 movl %fs:CANCELHANDLING, %eax
492: movl %eax, %r11d
50 orl $TCB_CANCELTYPE_BITMASK, %r11d
51 cmpl %eax, %r11d
52 je 1f
53
54 lock
55 cmpxchgl %r11d, %fs:CANCELHANDLING
56 jnz 2b
57
58 andl $(TCB_CANCELSTATE_BITMASK|TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK|TCB_EXITING_BITMASK|TCB_CANCEL_RESTMASK|TCB_TERMINATED_BITMASK), %r11d
59 cmpl $(TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK), %r11d
60 je 3f
61
621: ret
63
643: subq $8, %rsp
65 cfi_adjust_cfa_offset(8)
66 LP_OP(mov) $TCB_PTHREAD_CANCELED, %fs:RESULT
67 lock
68 orl $TCB_EXITING_BITMASK, %fs:CANCELHANDLING
69 mov %fs:CLEANUP_JMP_BUF, %RDI_LP
70 call PTHREAD_UNWIND
71 hlt
72END(__pthread_enable_asynccancel)
73
74
75 .hidden __pthread_disable_asynccancel
76ENTRY(__pthread_disable_asynccancel)
77 testl $TCB_CANCELTYPE_BITMASK, %edi
78 jnz 1f
79
80 movl %fs:CANCELHANDLING, %eax
812: movl %eax, %r11d
82 andl $~TCB_CANCELTYPE_BITMASK, %r11d
83 lock
84 cmpxchgl %r11d, %fs:CANCELHANDLING
85 jnz 2b
86
87 movl %r11d, %eax
883: andl $(TCB_CANCELING_BITMASK|TCB_CANCELED_BITMASK), %eax
89 cmpl $TCB_CANCELING_BITMASK, %eax
90 je 4f
911: ret
92
93 /* Performance doesn't matter in this loop. We will
94 delay until the thread is canceled. And we will unlikely
95 enter the loop twice. */
964: mov %fs:0, %RDI_LP
97 movl $__NR_futex, %eax
98 xorq %r10, %r10
99 addq $CANCELHANDLING, %rdi
100 LOAD_PRIVATE_FUTEX_WAIT (%esi)
101 syscall
102 movl %fs:CANCELHANDLING, %eax
103 jmp 3b
104END(__pthread_disable_asynccancel)
105