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[x86,x86_64] Fix libgcc unwinding through signal

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This change provides __restore/__restore_rt on x86 and __restore_rt on
x86_64 with unwinding information to be able to unwind through signal
frame via libgcc provided unwinding interface. See comments inlined for
more details.

Also remove the test that had a dependency on
__attribute__((cleanup(foo_cleanup))). It doesn't provide us with any
better test coverage than we have from the newer tests, and it doesn't
work well across a variety architectures (presumably because no one uses
this attribute in the real world).

Tested this on host via bionic-unit-tests-run-on-host on both x86 and
x86-64.

Bug: 17436734
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>

(cherry picked from commit 50321e2e66)

Change-Id: Iba90e36958b00c7cc7db5eeebf888dc89ce4d619
This commit is contained in:
Pavel Chupin 2014-09-26 16:02:09 +04:00 committed by Elliott Hughes
parent 190dce9e56
commit 8eb8c39299
8 changed files with 225 additions and 118 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

104
libc/arch-x86/bionic/__restore.S
View File

@ -28,10 +28,108 @@
#include <private/bionic_asm.h>
// This function must have exactly this instruction sequence for gdb and libunwind.
// This function must have exactly this name for gdb.
ENTRY(__restore)
// DWARF constants.
#define DW_CFA_def_cfa_expression 0x0f
#define DW_CFA_expression 0x10
#define DW_EH_PE_pcrel 0x10
#define DW_EH_PE_sdata4 0x0b
#define DW_OP_breg4 0x74
#define DW_OP_deref 0x06
// Offsets into struct sigcontext.
#define OFFSET_EDI 16
#define OFFSET_ESI 20
#define OFFSET_EBP 24
#define OFFSET_ESP 28
#define OFFSET_EBX 32
#define OFFSET_EDX 36
#define OFFSET_ECX 40
#define OFFSET_EAX 44
#define OFFSET_EIP 56
// Non-standard DWARF constants for the x86 registers.
#define DW_x86_REG_EAX 0
#define DW_x86_REG_ECX 1
#define DW_x86_REG_EDX 2
#define DW_x86_REG_EBX 3
#define DW_x86_REG_EBP 5
#define DW_x86_REG_ESI 6
#define DW_x86_REG_EDI 7
#define DW_x86_REG_EIP 8
#define cfi_signal_frame_start(f) \
.section .eh_frame,"a",@progbits; \
.L ## f ## _START_EH_FRAME: \
.long 2f - 1f; /* CIE length. */ \
1:.long 0; /* CIE ID. */ \
.byte 1; /* Version. */ \
.string "zRS"; /* Augmentation string. */ \
.uleb128 1; /* Code alignment factor. */ \
.sleb128 -4; /* Data alignment factor. */ \
.uleb128 DW_x86_REG_EIP; /* Return address register. */ \
.uleb128 1; /* 1 byte of augmentation data. */ \
.byte (DW_EH_PE_pcrel|DW_EH_PE_sdata4); /* FDE encoding. */ \
.align 8; \
2: \
.long .L ## f ## _END_FDE - .L ## f ## _START_FDE; /* FDE length. */ \
.L ## f ## _START_FDE: \
.long .L ## f ## _START_FDE - .L ## f ## _START_EH_FRAME; /* CIE location. */ \
.long (.L ## f ## _START - 1) - .; /* pcrel start address (see FDE encoding above). */ \
.long .L ## f ## _END - (.L ## f ## _START - 1); /* Function this FDE applies to. */ \
.uleb128 0; /* FDE augmentation length. */ \
#define cfi_signal_frame_end(f) \
.L ## f ## _END_FDE: \
#define cfi_def_cfa(offset) \
.byte DW_CFA_def_cfa_expression; \
.uleb128 2f-1f; \
1:.byte DW_OP_breg4; \
.sleb128 offset; \
.byte DW_OP_deref; \
2: \
#define cfi_offset(reg_number,offset) \
.byte DW_CFA_expression; \
.uleb128 reg_number; \
.uleb128 2f-1f; \
1:.byte DW_OP_breg4; \
.sleb128 offset; \
2: \
ENTRY_PRIVATE(__restore)
.L__restore_START:
popl %eax
movl $__NR_sigreturn, %eax
int $0x80
.L__restore_END:
END(__restore)
cfi_signal_frame_start(__restore)
cfi_def_cfa(OFFSET_ESP + 4)
cfi_offset(DW_x86_REG_EDI, OFFSET_EDI + 4)
cfi_offset(DW_x86_REG_ESI, OFFSET_ESI + 4)
cfi_offset(DW_x86_REG_EBP, OFFSET_EBP + 4)
cfi_offset(DW_x86_REG_EBX, OFFSET_EBX + 4)
cfi_offset(DW_x86_REG_EDX, OFFSET_EDX + 4)
cfi_offset(DW_x86_REG_ECX, OFFSET_ECX + 4)
cfi_offset(DW_x86_REG_EAX, OFFSET_EAX + 4)
cfi_offset(DW_x86_REG_EIP, OFFSET_EIP + 4)
cfi_signal_frame_end(__restore)
ENTRY_PRIVATE(__restore_rt)
.L__restore_rt_START:
movl $__NR_rt_sigreturn, %eax
int $0x80
.L__restore_rt_END:
END(__restore_rt)
cfi_signal_frame_start(__restore_rt)
cfi_def_cfa(OFFSET_ESP + 160)
cfi_offset(DW_x86_REG_EDI, OFFSET_EDI + 160)
cfi_offset(DW_x86_REG_ESI, OFFSET_ESI + 160)
cfi_offset(DW_x86_REG_EBP, OFFSET_EBP + 160)
cfi_offset(DW_x86_REG_EBX, OFFSET_EBX + 160)
cfi_offset(DW_x86_REG_EDX, OFFSET_EDX + 160)
cfi_offset(DW_x86_REG_ECX, OFFSET_ECX + 160)
cfi_offset(DW_x86_REG_EAX, OFFSET_EAX + 160)
cfi_offset(DW_x86_REG_EIP, OFFSET_EIP + 160)
cfi_signal_frame_end(__restore_rt)

36
libc/arch-x86/bionic/__restore_rt.S
View File

@ -1,36 +0,0 @@
/*
* Copyright (C) 2014 The 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:
* * 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.
*
* 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.
*/
#include <private/bionic_asm.h>
// This function must have exactly this instruction sequence for gdb and libunwind.
// This function must have exactly this name for gdb.
ENTRY(__restore_rt)
movl $__NR_rt_sigreturn, %eax
int $0x80
END(__restore_rt)

1
libc/arch-x86/x86.mk
View File

@ -26,7 +26,6 @@ libc_bionic_src_files_x86 += \
arch-x86/bionic/__bionic_clone.S \
arch-x86/bionic/_exit_with_stack_teardown.S \
arch-x86/bionic/libgcc_compat.c \
arch-x86/bionic/__restore_rt.S \
arch-x86/bionic/__restore.S \
arch-x86/bionic/_setjmp.S \
arch-x86/bionic/setjmp.S \

113
libc/arch-x86_64/bionic/__restore_rt.S
View File

@ -28,9 +28,116 @@
#include <private/bionic_asm.h>
// This function must have exactly this instruction sequence for gdb and libunwind.
// This function must have exactly this name for gdb.
ENTRY(__restore_rt)
// DWARF constants.
#define DW_CFA_def_cfa_expression 0x0f
#define DW_CFA_expression 0x10
#define DW_EH_PE_pcrel 0x10
#define DW_EH_PE_sdata4 0x0b
#define DW_OP_breg4 0x74
#define DW_OP_breg7 0x77
#define DW_OP_deref 0x06
// Offsets into struct ucontext_t of uc_mcontext.gregs[x].
#define OFFSET_R8 40
#define OFFSET_R9 48
#define OFFSET_R10 56
#define OFFSET_R11 64
#define OFFSET_R12 72
#define OFFSET_R13 80
#define OFFSET_R14 88
#define OFFSET_R15 96
#define OFFSET_RDI 104
#define OFFSET_RSI 112
#define OFFSET_RBP 120
#define OFFSET_RSP 160
#define OFFSET_RBX 128
#define OFFSET_RDX 136
#define OFFSET_RAX 144
#define OFFSET_RCX 152
#define OFFSET_RIP 168
// Non-standard DWARF constants for the x86-64 registers.
#define DW_x86_64_RAX 0
#define DW_x86_64_RDX 1
#define DW_x86_64_RCX 2
#define DW_x86_64_RBX 3
#define DW_x86_64_RSI 4
#define DW_x86_64_RDI 5
#define DW_x86_64_RBP 6
#define DW_x86_64_RSP 7
#define DW_x86_64_R8 8
#define DW_x86_64_R9 9
#define DW_x86_64_R10 10
#define DW_x86_64_R11 11
#define DW_x86_64_R12 12
#define DW_x86_64_R13 13
#define DW_x86_64_R14 14
#define DW_x86_64_R15 15
#define DW_x86_64_RIP 16
#define cfi_signal_frame_start(f) \
.section .eh_frame,"a",@progbits; \
.L ## f ## _START_EH_FRAME: \
.long 2f - 1f; /* CIE length. */ \
1:.long 0; /* CIE ID. */ \
.byte 1; /* Version. */ \
.string "zRS"; /* Augmentation string. */ \
.uleb128 1; /* Code alignment factor. */ \
.sleb128 -8; /* Data alignment factor. */ \
.uleb128 DW_x86_64_RIP; /* Return address register. */ \
.uleb128 1; /* 1 byte of augmentation data. */ \
.byte (DW_EH_PE_pcrel | DW_EH_PE_sdata4); /* FDE encoding. */ \
.align 8; \
2: \
.long .L ## f ## _END_FDE - .L ## f ## _START_FDE; /* FDE length. */ \
.L ## f ## _START_FDE: \
.long .L ## f ## _START_FDE - .L ## f ## _START_EH_FRAME; /* CIE location. */ \
.long (.L ## f ## _START - 1) - .; /* pcrel start address (see FDE encoding above). */ \
.long .L ## f ## _END - (.L ## f ## _START - 1); /* Function this FDE applies to. */ \
.uleb128 0; /* FDE augmentation length. */ \
#define cfi_signal_frame_end(f) \
.L ## f ## _END_FDE: \
#define cfi_def_cfa(offset) \
.byte DW_CFA_def_cfa_expression; \
.uleb128 2f-1f; \
1:.byte DW_OP_breg7; \
.sleb128 offset; \
.byte DW_OP_deref; \
2: \
#define cfi_offset(reg_number,offset) \
.byte DW_CFA_expression; \
.uleb128 reg_number; \
.uleb128 2f-1f; \
1:.byte DW_OP_breg7; \
.sleb128 offset; \
2: \
ENTRY_PRIVATE(__restore_rt)
.L__restore_rt_START:
mov $__NR_rt_sigreturn, %rax
syscall
.L__restore_rt_END:
END(__restore_rt)
cfi_signal_frame_start(__restore_rt)
cfi_def_cfa(OFFSET_RSP)
cfi_offset(DW_x86_64_R8, OFFSET_R8)
cfi_offset(DW_x86_64_R9, OFFSET_R9)
cfi_offset(DW_x86_64_R10, OFFSET_R10)
cfi_offset(DW_x86_64_R11, OFFSET_R11)
cfi_offset(DW_x86_64_R12, OFFSET_R12)
cfi_offset(DW_x86_64_R13, OFFSET_R13)
cfi_offset(DW_x86_64_R14, OFFSET_R14)
cfi_offset(DW_x86_64_R15, OFFSET_R15)
cfi_offset(DW_x86_64_RDI, OFFSET_RDI)
cfi_offset(DW_x86_64_RSI, OFFSET_RSI)
cfi_offset(DW_x86_64_RBP, OFFSET_RBP)
cfi_offset(DW_x86_64_RSP, OFFSET_RSP)
cfi_offset(DW_x86_64_RBX, OFFSET_RBX)
cfi_offset(DW_x86_64_RDX, OFFSET_RDX)
cfi_offset(DW_x86_64_RAX, OFFSET_RAX)
cfi_offset(DW_x86_64_RCX, OFFSET_RCX)
cfi_offset(DW_x86_64_RIP, OFFSET_RIP)
cfi_signal_frame_end(__restore_rt)

3
tests/Android.mk
View File

@ -88,6 +88,7 @@ libBionicStandardTests_src_files := \
search_test.cpp \
signal_test.cpp \
stack_protector_test.cpp \
stack_unwinding_test.cpp \
stdatomic_test.cpp \
stdint_test.cpp \
stdio_test.cpp \
@ -224,8 +225,6 @@ bionic-unit-tests_src_files := \
atexit_test.cpp \
dlext_test.cpp \
dlfcn_test.cpp \
stack_unwinding_test.cpp \
stack_unwinding_test_impl.c \
bionic-unit-tests_cflags := $(test_cflags)

5
tests/ScopedSignalHandler.h
View File

@ -21,9 +21,10 @@
class ScopedSignalHandler {
public:
ScopedSignalHandler(int signal_number, void (*handler)(int)) : signal_number_(signal_number) {
ScopedSignalHandler(int signal_number, void (*handler)(int), int sa_flags = 0)
: signal_number_(signal_number) {
sigemptyset(&action_.sa_mask);
action_.sa_flags = 0;
action_.sa_flags = sa_flags;
action_.sa_handler = handler;
sigaction(signal_number_, &action_, &old_action_);
}

17
tests/stack_unwinding_test.cpp
View File

@ -31,7 +31,8 @@
#include "ScopedSignalHandler.h"
#define noinline __attribute__((noinline))
#define noinline __attribute__((__noinline__))
#define __unused __attribute__((__unused__))
static _Unwind_Reason_Code FrameCounter(_Unwind_Context* ctx __unused, void* arg) {
int* count_ptr = reinterpret_cast<int*>(arg);
@ -85,6 +86,7 @@ static void noinline UnwindSignalHandler(int) {
}
TEST(stack_unwinding, unwind_through_signal_frame) {
killer_count = handler_count = handler_one_deeper_count = 0;
ScopedSignalHandler ssh(SIGUSR1, UnwindSignalHandler);
_Unwind_Backtrace(FrameCounter, &killer_count);
@ -92,11 +94,12 @@ TEST(stack_unwinding, unwind_through_signal_frame) {
ASSERT_EQ(0, kill(getpid(), SIGUSR1));
}
extern "C" void unwind_through_frame_with_cleanup_function();
// On LP32, the SA_SIGINFO flag gets you __restore_rt instead of __restore.
TEST(stack_unwinding, unwind_through_signal_frame_SA_SIGINFO) {
killer_count = handler_count = handler_one_deeper_count = 0;
ScopedSignalHandler ssh(SIGUSR1, UnwindSignalHandler, SA_SIGINFO);
// We have to say "DeathTest" here so gtest knows to run this test (which exits)
// in its own process.
TEST(stack_unwinding_DeathTest, unwind_through_frame_with_cleanup_function) {
::testing::FLAGS_gtest_death_test_style = "threadsafe";
ASSERT_EXIT(unwind_through_frame_with_cleanup_function(), ::testing::ExitedWithCode(42), "");
_Unwind_Backtrace(FrameCounter, &killer_count);
ASSERT_EQ(0, kill(getpid(), SIGUSR1));
}

64
tests/stack_unwinding_test_impl.c
View File

@ -1,64 +0,0 @@
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Contributed by: Intel Corporation
*/
#include <dlfcn.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <unwind.h>
#define noinline __attribute__((__noinline__))
#ifndef __unused
#define __unused __attribute__((__unused__))
#endif
static noinline _Unwind_Reason_Code cleanup_unwind_fn(int a __unused,
_Unwind_Action action,
_Unwind_Exception_Class b __unused,
struct _Unwind_Exception* c __unused,
struct _Unwind_Context* ctx __unused,
void* e __unused) {
if ((action & _UA_END_OF_STACK) != 0) {
abort(); // We reached the end of the stack without executing foo_cleanup (which would have exited). Test failed.
}
return _URC_NO_REASON;
}
static void noinline foo_cleanup(char* param __unused) {
exit(42);
}
static void noinline function_with_cleanup_function() {
char c __attribute__((cleanup(foo_cleanup))) __unused;
*((int*) 1) = 0;
}
static void noinline cleanup_sigsegv_handler(int param __unused) {
struct _Unwind_Exception* exception = (struct _Unwind_Exception*) calloc(1, sizeof(*exception));
_Unwind_ForcedUnwind(exception, cleanup_unwind_fn, 0);
}
void unwind_through_frame_with_cleanup_function() {
signal(SIGSEGV, &cleanup_sigsegv_handler);
function_with_cleanup_function();
}