platform_bionic/libc/arch-x86_64/bionic/setjmp.S
Elliott Hughes c0d41db92e setjmp/longjmp: avoid invalid values in the stack pointer.
arm64 was already being careful, but x86/x86-64 and 32-bit ARM could be
caught by a signal in a state where the stack pointer was mangled.

For 32-bit ARM I've taken care with the link register too, to avoid
potential issues with unwinding.

Bug: http://b/152210274
Test: treehugger
Change-Id: I1ce285b017a633c732dbe04743368f4cae27af85
2021-04-05 17:43:36 -07:00

209 lines
5.8 KiB
ArmAsm

/*
* Copyright (c) 2001 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Frank van der Linden for Wasabi Systems, Inc.
*
* 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 for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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>
// The internal structure of a jmp_buf is totally private.
// Current layout (changes from release to release):
//
// word name description
// 0 rbx registers
// 1 rbp
// 2 r12
// 3 r13
// 4 r14
// 5 r15
// 6 rsp
// 7 pc
// 8 sigflag/cookie setjmp cookie in top 31 bits, signal mask flag in low bit
// 9 sigmask signal mask (includes rt signals as well)
// 10 checksum checksum of the core registers, to give better error messages.
#define _JB_RBX 0
#define _JB_RBP 1
#define _JB_R12 2
#define _JB_R13 3
#define _JB_R14 4
#define _JB_R15 5
#define _JB_RSP 6
#define _JB_PC 7
#define _JB_SIGFLAG 8
#define _JB_SIGMASK 9
#define _JB_CHECKSUM 10
.macro m_calculate_checksum dst, src
movq $0, \dst
.irp i,0,1,2,3,4,5,6,7
xorq (\i*8)(\src), \dst
.endr
.endm
ENTRY(setjmp)
__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(setjmp)
movl $1,%esi
jmp PIC_PLT(sigsetjmp)
END(setjmp)
ENTRY(_setjmp)
__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(_setjmp)
movl $0,%esi
jmp PIC_PLT(sigsetjmp)
END(_setjmp)
// int sigsetjmp(sigjmp_buf env, int save_signal_mask);
ENTRY(sigsetjmp)
__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(sigsetjmp)
pushq %rdi
movq %rsi,%rdi
call PIC_PLT(__bionic_setjmp_cookie_get)
popq %rdi
// Record setjmp cookie and whether or not we're saving the signal mask.
movq %rax,(_JB_SIGFLAG * 8)(%rdi)
pushq %rax
// Do we need to save the signal mask?
testq $1,%rax
jz 2f
// Save current signal mask.
pushq %rdi // Push 'env'.
// The 'how' argument is ignored if new_mask is NULL.
xorq %rsi,%rsi // NULL.
leaq (_JB_SIGMASK * 8)(%rdi),%rdx // old_mask.
call PIC_PLT(sigprocmask)
popq %rdi // Pop 'env'.
2:
// Fetch the setjmp cookie and clear the signal flag bit.
popq %rax
andq $-2,%rax
movq (%rsp),%r11
// Save the callee-save registers.
.macro m_mangle_register reg, offset
movq \reg, (\offset * 8)(%rdi)
xorq %rax, (\offset * 8)(%rdi) // %rax contains the cookie.
.endm
m_mangle_register %rbx, _JB_RBX
m_mangle_register %rbp, _JB_RBP
m_mangle_register %r12, _JB_R12
m_mangle_register %r13, _JB_R13
m_mangle_register %r14, _JB_R14
m_mangle_register %r15, _JB_R15
m_mangle_register %rsp, _JB_RSP
m_mangle_register %r11, _JB_PC
m_calculate_checksum %rax, %rdi
movq %rax, (_JB_CHECKSUM * 8)(%rdi)
xorl %eax,%eax
ret
END(sigsetjmp)
// void siglongjmp(sigjmp_buf env, int value);
ENTRY(siglongjmp)
__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(siglongjmp)
movq %rdi,%r12
pushq %rsi // Push 'value'.
m_calculate_checksum %rax, %rdi
xorq (_JB_CHECKSUM * 8)(%rdi), %rax
jnz 3f
// Do we need to restore the signal mask?
movq (_JB_SIGFLAG * 8)(%rdi), %rdi
pushq %rdi // Push cookie
testq $1, %rdi
jz 2f
// Restore the signal mask.
movq $2,%rdi // SIG_SETMASK.
leaq (_JB_SIGMASK * 8)(%r12),%rsi // new_mask.
xorq %rdx,%rdx // NULL.
call PIC_PLT(sigprocmask)
2:
// Fetch the setjmp cookie and clear the signal flag bit.
popq %rcx
andq $-2, %rcx
popq %rax // Pop 'value'.
// Restore the callee-save registers.
.macro m_unmangle_register reg, offset
movq (\offset * 8)(%r12), %rdx // Clobbers rdx.
xorq %rcx, %rdx // %rcx contains the cookie.
// Now it's safe to overwrite the register (http://b/152210274).
movq %rdx, \reg
.endm
m_unmangle_register %rbx, _JB_RBX
m_unmangle_register %rbp, _JB_RBP
m_unmangle_register %r13, _JB_R13
m_unmangle_register %r14, _JB_R14
m_unmangle_register %r15, _JB_R15
m_unmangle_register %rsp, _JB_RSP
m_unmangle_register %r11, _JB_PC
m_unmangle_register %r12, _JB_R12
// Check the cookie.
pushq %rax
pushq %r11
movq %rcx, %rdi
call PIC_PLT(__bionic_setjmp_cookie_check)
popq %r11
popq %rax
// Return 1 if value is 0.
testl %eax,%eax
jnz 1f
incl %eax
1:
movq %r11,0(%rsp)
ret
3:
call PIC_PLT(__bionic_setjmp_checksum_mismatch)
END(siglongjmp)
ALIAS_SYMBOL(longjmp, siglongjmp)
__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(longjmp)
ALIAS_SYMBOL(_longjmp, siglongjmp)
__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(_longjmp)