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/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <dlfcn.h>
#include <stdio.h>
#include <unwind.h>
#include <pthreadP.h>
static void *libgcc_s_handle;
static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
static _Unwind_Reason_Code (*libgcc_s_personality)
(_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
(struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
void
__attribute_noinline__
pthread_cancel_init (void)
{
void *resume, *personality, *forcedunwind, *getcfa;
void *handle;
if (__builtin_expect (libgcc_s_handle != NULL, 1))
{
/* Force gcc to reload all values. */
asm volatile ("" ::: "memory");
return;
}
handle = __libc_dlopen ("libgcc_s.so.1");
if (handle == NULL
|| (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
|| (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
|| (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
== NULL
|| (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
#ifdef ARCH_CANCEL_INIT
|| ARCH_CANCEL_INIT (handle)
#endif
)
__libc_fatal ("libgcc_s.so.1 must be installed for pthread_cancel to work\n");
libgcc_s_resume = resume;
libgcc_s_personality = personality;
libgcc_s_forcedunwind = forcedunwind;
libgcc_s_getcfa = getcfa;
/* Make sure libgcc_s_getcfa is written last. Otherwise,
pthread_cancel_init might return early even when the pointer the
caller is interested in is not initialized yet. */
atomic_write_barrier ();
libgcc_s_handle = handle;
}
void
__libc_freeres_fn_section
__unwind_freeres (void)
{
void *handle = libgcc_s_handle;
if (handle != NULL)
{
libgcc_s_handle = NULL;
__libc_dlclose (handle);
}
}
/* It's vitally important that _Unwind_Resume not have a stack frame; the
ARM unwinder relies on register state at entrance. So we write this in
assembly. */
#define STR1(S) #S
#define STR(S) STR1(S)
asm (
" .globl _Unwind_Resume\n"
" .type _Unwind_Resume, %function\n"
"_Unwind_Resume:\n"
" .cfi_sections .debug_frame\n"
" " CFI_STARTPROC "\n"
" push {r4, r5, r6, lr}\n"
" " CFI_ADJUST_CFA_OFFSET (16)" \n"
" " CFI_REL_OFFSET (r4, 0) "\n"
" " CFI_REL_OFFSET (r5, 4) "\n"
" " CFI_REL_OFFSET (r6, 8) "\n"
" " CFI_REL_OFFSET (lr, 12) "\n"
" " CFI_REMEMBER_STATE "\n"
" ldr r4, 1f\n"
" ldr r5, 2f\n"
"3: add r4, pc, r4\n"
" ldr r3, [r4, r5]\n"
" mov r6, r0\n"
" cmp r3, #0\n"
" beq 4f\n"
"5: mov r0, r6\n"
" pop {r4, r5, r6, lr}\n"
" " CFI_ADJUST_CFA_OFFSET (-16) "\n"
" " CFI_RESTORE (r4) "\n"
" " CFI_RESTORE (r5) "\n"
" " CFI_RESTORE (r6) "\n"
" " CFI_RESTORE (lr) "\n"
" bx r3\n"
" " CFI_RESTORE_STATE "\n"
"4: bl pthread_cancel_init\n"
" ldr r3, [r4, r5]\n"
" b 5b\n"
" " CFI_ENDPROC "\n"
" .align 2\n"
"1: .word _GLOBAL_OFFSET_TABLE_ - 3b - " STR (PC_OFS) "\n"
"2: .word libgcc_s_resume(GOTOFF)\n"
" .size _Unwind_Resume, .-_Unwind_Resume\n"
);
_Unwind_Reason_Code
__gcc_personality_v0 (_Unwind_State state,
struct _Unwind_Exception *ue_header,
struct _Unwind_Context *context)
{
if (__builtin_expect (libgcc_s_personality == NULL, 0))
pthread_cancel_init ();
return libgcc_s_personality (state, ue_header, context);
}
_Unwind_Reason_Code
_Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
void *stop_argument)
{
if (__builtin_expect (libgcc_s_forcedunwind == NULL, 0))
pthread_cancel_init ();
return libgcc_s_forcedunwind (exc, stop, stop_argument);
}
_Unwind_Word
_Unwind_GetCFA (struct _Unwind_Context *context)
{
if (__builtin_expect (libgcc_s_getcfa == NULL, 0))
pthread_cancel_init ();
return libgcc_s_getcfa (context);
}
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