platform_bionic/libc/arch-arm/bionic/setjmp.S
Elliott Hughes 75096226c8 Switch arm and arm64 over to the x86 style of jmpbuf.
Specifically, use the argument to sigsetjmp as a flag in the buffer
to indicate whether or not the signal mask is valid.

Bug: 16918359
Change-Id: I5bb1f1220f14c105c6bc57e0c28c1dc366d1438f
2014-12-08 16:15:59 -08:00

175 lines
5.1 KiB
ArmAsm

/*
* Copyright (c) 1997 Mark Brinicombe
* Copyright (c) 2010 Android Open Source Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Mark Brinicombe
* 4. Neither the name of the University 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 AUTHOR 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 AUTHOR 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.
*/
#include <private/bionic_asm.h>
// According to the ARM AAPCS document, we only need to save
// the following registers:
//
// Core r4-r14
//
// VFP d8-d15 (see section 5.1.2.1)
//
// Registers s16-s31 (d8-d15, q4-q7) must be preserved across subroutine
// calls; registers s0-s15 (d0-d7, q0-q3) do not need to be preserved
// (and can be used for passing arguments or returning results in standard
// procedure-call variants). Registers d16-d31 (q8-q15), if present, do
// not need to be preserved.
//
// FPSCR saved because glibc does.
// The internal structure of a jmp_buf is totally private.
// Current layout (may change in the future):
//
// word name description
// 0 magic magic number
// 1 sigmask signal mask (not used with _setjmp / _longjmp)
// 2 float_base base of float registers (d8 to d15)
// 18 float_state floating-point status and control register
// 19 core_base base of core registers (r4 to r14)
// 30 reserved reserved entries (room to grow)
// 64
//
// NOTE: float_base must be at an even word index, since the
// FP registers will be loaded/stored with instructions
// that expect 8-byte alignment.
#define _JB_SIGFLAG 0
#define _JB_SIGMASK (_JB_SIGFLAG+1)
#define _JB_FLOAT_BASE (_JB_SIGMASK+1)
#define _JB_FLOAT_STATE (_JB_FLOAT_BASE + (15-8+1)*2)
#define _JB_CORE_BASE (_JB_FLOAT_STATE+1)
ENTRY(setjmp)
mov r1, #1
b sigsetjmp
END(setjmp)
ENTRY(_setjmp)
mov r1, #0
b sigsetjmp
END(_setjmp)
// int sigsetjmp(sigjmp_buf env, int save_signal_mask);
ENTRY(sigsetjmp)
// Record whether or not we're saving the signal mask.
str r1, [r0, #(_JB_SIGFLAG * 4)]
// Do we need to save the signal mask?
teq r1, #0
beq 1f
// Get current signal mask.
stmfd sp!, {r0, r14}
.cfi_def_cfa_offset 8
.cfi_rel_offset r0, 0
.cfi_rel_offset r14, 4
mov r0, #0
bl sigblock
mov r1, r0
ldmfd sp!, {r0, r14}
.cfi_def_cfa_offset 0
// Save the signal mask.
str r1, [r0, #(_JB_SIGMASK * 4)]
1:
// Save core registers.
add r1, r0, #(_JB_CORE_BASE * 4)
stmia r1, {r4-r14}
// Save floating-point registers.
add r1, r0, #(_JB_FLOAT_BASE * 4)
vstmia r1, {d8-d15}
// Save floating-point state.
fmrx r1, fpscr
str r1, [r0, #(_JB_FLOAT_STATE * 4)]
mov r0, #0
bx lr
END(sigsetjmp)
// void siglongjmp(sigjmp_buf env, int value);
ENTRY(siglongjmp)
// Do we need to restore the signal mask?
ldr r2, [r0, #(_JB_SIGFLAG * 4)]
teq r2, #0
beq 1f
// Restore the signal mask.
stmfd sp!, {r0, r1, r14}
.cfi_def_cfa_offset 12
.cfi_rel_offset r0, 0
.cfi_rel_offset r1, 4
.cfi_rel_offset r14, 8
sub sp, sp, #4 // Align the stack.
.cfi_adjust_cfa_offset 4
ldr r0, [r0, #(_JB_SIGMASK * 4)]
bl sigsetmask
add sp, sp, #4 // Unalign the stack.
.cfi_adjust_cfa_offset -4
ldmfd sp!, {r0, r1, r14}
.cfi_def_cfa_offset 0
1:
// Restore floating-point registers.
add r2, r0, #(_JB_FLOAT_BASE * 4)
vldmia r2, {d8-d15}
// Restore floating-point state.
ldr r2, [r0, #(_JB_FLOAT_STATE * 4)]
fmxr fpscr, r2
// Restore core registers.
add r2, r0, #(_JB_CORE_BASE * 4)
ldmia r2, {r4-r14}
// Validate sp and r14.
teq sp, #0
teqne r14, #0
bleq longjmperror
// Set return value.
mov r0, r1
teq r0, #0
moveq r0, #1
bx lr
END(siglongjmp)
.globl longjmp
.equ longjmp, siglongjmp
.globl _longjmp
.equ _longjmp, siglongjmp