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// Copyright (c) 2012, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// A minimalistic implementation of getcontext() to be used by
// Google Breakpad on Android.
#include "common/android/ucontext_constants.h"
/* int getcontext (ucontext_t *ucp) */
#ifdef __arm__
.text
.global breakpad_getcontext
.hidden breakpad_getcontext
.type breakpad_getcontext, #function
.align 0
.fnstart
breakpad_getcontext:
/* First, save r4-r11 */
add r1, r0, #(MCONTEXT_GREGS_OFFSET + 4*4)
stm r1, {r4-r11}
/* r12 is a scratch register, don't save it */
/* Save sp and lr explicitely. */
/* - sp can't be stored with stmia in Thumb-2 */
/* - STM instructions that store sp and pc are deprecated in ARM */
str sp, [r0, #(MCONTEXT_GREGS_OFFSET + 13*4)]
str lr, [r0, #(MCONTEXT_GREGS_OFFSET + 14*4)]
/* Save the caller's address in 'pc' */
str lr, [r0, #(MCONTEXT_GREGS_OFFSET + 15*4)]
/* Save ucontext_t* pointer accross next call */
mov r4, r0
/* Call sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask)) */
mov r0, #0 /* SIG_BLOCK */
mov r1, #0 /* NULL */
add r2, r4, #UCONTEXT_SIGMASK_OFFSET
bl sigprocmask(PLT)
/* Intentionally do not save the FPU state here. This is because on
* Linux/ARM, one should instead use ptrace(PTRACE_GETFPREGS) or
* ptrace(PTRACE_GETVFPREGS) to get it.
*
* Note that a real implementation of getcontext() would need to save
* this here to allow setcontext()/swapcontext() to work correctly.
*/
/* Restore the values of r4 and lr */
mov r0, r4
ldr lr, [r0, #(MCONTEXT_GREGS_OFFSET + 14*4)]
ldr r4, [r0, #(MCONTEXT_GREGS_OFFSET + 4*4)]
/* Return 0 */
mov r0, #0
bx lr
.fnend
.size breakpad_getcontext, . - breakpad_getcontext
#elif defined(__i386__)
.text
.global breakpad_getcontext
.hidden breakpad_getcontext
.align 4
.type breakpad_getcontext, @function
breakpad_getcontext:
movl 4(%esp), %eax /* eax = uc */
/* Save register values */
movl %ecx, MCONTEXT_ECX_OFFSET(%eax)
movl %edx, MCONTEXT_EDX_OFFSET(%eax)
movl %ebx, MCONTEXT_EBX_OFFSET(%eax)
movl %edi, MCONTEXT_EDI_OFFSET(%eax)
movl %esi, MCONTEXT_ESI_OFFSET(%eax)
movl %ebp, MCONTEXT_EBP_OFFSET(%eax)
movl (%esp), %edx /* return address */
lea 4(%esp), %ecx /* exclude return address from stack */
mov %edx, MCONTEXT_EIP_OFFSET(%eax)
mov %ecx, MCONTEXT_ESP_OFFSET(%eax)
xorl %ecx, %ecx
movw %fs, %cx
mov %ecx, MCONTEXT_FS_OFFSET(%eax)
movl $0, MCONTEXT_EAX_OFFSET(%eax)
/* Save floating point state to fpregstate, then update
* the fpregs pointer to point to it */
leal UCONTEXT_FPREGS_MEM_OFFSET(%eax), %ecx
fnstenv (%ecx)
fldenv (%ecx)
mov %ecx, UCONTEXT_FPREGS_OFFSET(%eax)
/* Save signal mask: sigprocmask(SIGBLOCK, NULL, &uc->uc_sigmask) */
leal UCONTEXT_SIGMASK_OFFSET(%eax), %edx
xorl %ecx, %ecx
push %edx /* &uc->uc_sigmask */
push %ecx /* NULL */
push %ecx /* SIGBLOCK == 0 on i386 */
call sigprocmask@PLT
addl $12, %esp
movl $0, %eax
ret
.size breakpad_getcontext, . - breakpad_getcontext
#else
#error "This file has not been ported for your CPU!"
#endif
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