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Fix signal trampolines.

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* LP32 should use sa_restorer too. gdb expects this, and future (>= 3.15) x86
  kernels will apparently stop supporting the case where SA_RESTORER isn't
  set.

* gdb and libunwind care about the exact instruction sequences, so we need to
  modify the code slightly in a few cases to match what they're looking for.

* gdb also cares about the exact function names (for some architectures),
  so we need to use __restore and __restore_rt rather than __sigreturn and
  __rt_sigreturn.

* It's possible that we don't have a VDSO; dl_iterate_phdr shouldn't assume
  that getauxval(AT_SYSINFO_EHDR) will return a non-null pointer.

This fixes unwinding through a signal handler in gdb for all architectures.
It doesn't fix libunwind for arm and arm64. I'll keep investigating that...

(cherry picked from commit 36f451a6d9)

Bug: 17436734
Change-Id: Ic1ea1184db6655c5d96180dc07bcc09628e647cb
This commit is contained in:
Elliott Hughes 2014-09-10 15:20:40 -07:00
parent aa6cd5819c
commit 7dc2b7b30d
12 changed files with 183 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
libc/arch-arm/arm.mk
View file

@ -55,6 +55,8 @@ libc_bionic_src_files_arm += \
arch-arm/bionic/_exit_with_stack_teardown.S \
arch-arm/bionic/libgcc_compat.c \
arch-arm/bionic/memcmp.S \
arch-arm/bionic/__restore_rt.S \
arch-arm/bionic/__restore.S \
arch-arm/bionic/_setjmp.S \
arch-arm/bionic/setjmp.S \
arch-arm/bionic/sigsetjmp.S \

35
libc/arch-arm/bionic/__restore.S Normal file
View file

@ -0,0 +1,35 @@
/*
* 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.
ENTRY_PRIVATE(__restore)
mov r7, #__NR_sigreturn
swi #0
END(__restore)

35
libc/arch-arm/bionic/__restore_rt.S Normal file
View file

@ -0,0 +1,35 @@
/*
* 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.
ENTRY_PRIVATE(__restore_rt)
mov r7, #__NR_rt_sigreturn
swi #0
END(__restore_rt)

2
libc/arch-arm64/arm64.mk
View file

@ -29,7 +29,7 @@ libc_common_src_files_arm64 += \
libc_bionic_src_files_arm64 := \
arch-arm64/bionic/__bionic_clone.S \
arch-arm64/bionic/_exit_with_stack_teardown.S \
arch-arm64/bionic/__rt_sigreturn.S \
arch-arm64/bionic/__restore_rt.S \
arch-arm64/bionic/_setjmp.S \
arch-arm64/bionic/setjmp.S \
arch-arm64/bionic/__set_tls.c \

9
libc/arch-arm64/bionic/__rt_sigreturn.S → libc/arch-arm64/bionic/__restore_rt.S
View file

@ -28,7 +28,8 @@
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__rt_sigreturn)
mov x8, __NR_rt_sigreturn
svc #0
END(__rt_sigreturn)
// This function must have exactly this instruction sequence for gdb and libunwind.
ENTRY_PRIVATE(__restore_rt)
mov x8, __NR_rt_sigreturn
svc #0
END(__restore_rt)

37
libc/arch-x86/bionic/__restore.S Normal file
View file

@ -0,0 +1,37 @@
/*
* 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)
popl %eax
movl $__NR_sigreturn, %eax
int $0x80
END(__restore)

36
libc/arch-x86/bionic/__restore_rt.S Normal file
View file

@ -0,0 +1,36 @@
/*
* 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)

2
libc/arch-x86/x86.mk
View file

@ -26,6 +26,8 @@ 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 \
arch-x86/bionic/__set_tls.c \

8
libc/arch-x86_64/bionic/__rt_sigreturn.S → libc/arch-x86_64/bionic/__restore_rt.S
View file

@ -28,7 +28,9 @@
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__rt_sigreturn)
movl $__NR_rt_sigreturn, %eax
// This function must have exactly this instruction sequence for gdb and libunwind.
// This function must have exactly this name for gdb.
ENTRY(__restore_rt)
mov $__NR_rt_sigreturn, %rax
syscall
END(__rt_sigreturn)
END(__restore_rt)

2
libc/arch-x86_64/x86_64.mk
View file

@ -30,7 +30,7 @@ libc_common_src_files_x86_64 += \
libc_bionic_src_files_x86_64 := \
arch-x86_64/bionic/__bionic_clone.S \
arch-x86_64/bionic/_exit_with_stack_teardown.S \
arch-x86_64/bionic/__rt_sigreturn.S \
arch-x86_64/bionic/__restore_rt.S \
arch-x86_64/bionic/_setjmp.S \
arch-x86_64/bionic/setjmp.S \
arch-x86_64/bionic/__set_tls.c \

5
libc/bionic/dl_iterate_phdr_static.cpp
View file

@ -62,6 +62,11 @@ int dl_iterate_phdr(int (*cb)(struct dl_phdr_info* info, size_t size, void* data
// Try the VDSO if that didn't work.
ElfW(Ehdr)* ehdr_vdso = reinterpret_cast<ElfW(Ehdr)*>(getauxval(AT_SYSINFO_EHDR));
if (ehdr_vdso == nullptr) {
// There is no VDSO, so there's nowhere left to look.
return rc;
}
struct dl_phdr_info vdso_info;
vdso_info.dlpi_addr = 0;
vdso_info.dlpi_name = NULL;

22
libc/bionic/sigaction.cpp
View file

@ -28,8 +28,10 @@
#include <signal.h>
extern "C" void __restore_rt(void);
extern "C" void __restore(void);
#if __LP64__
extern "C" void __rt_sigreturn(void);
extern "C" int __rt_sigaction(int, const struct __kernel_sigaction*, struct __kernel_sigaction*, size_t);
#else
extern "C" int __sigaction(int, const struct sigaction*, struct sigaction*);
@ -47,7 +49,7 @@ int sigaction(int signal, const struct sigaction* bionic_new_action, struct siga
if (!(kernel_new_action.sa_flags & SA_RESTORER)) {
kernel_new_action.sa_flags |= SA_RESTORER;
kernel_new_action.sa_restorer = &__rt_sigreturn;
kernel_new_action.sa_restorer = &__restore_rt;
}
#endif
}
@ -75,6 +77,20 @@ int sigaction(int signal, const struct sigaction* bionic_new_action, struct siga
#else
// The 32-bit ABI is broken. struct sigaction includes a too-small sigset_t.
// TODO: if we also had correct struct sigaction definitions available, we could copy in and out.
return __sigaction(signal, bionic_new_action, bionic_old_action);
struct sigaction kernel_new_action;
if (bionic_new_action != NULL) {
kernel_new_action.sa_flags = bionic_new_action->sa_flags;
kernel_new_action.sa_handler = bionic_new_action->sa_handler;
kernel_new_action.sa_mask = bionic_new_action->sa_mask;
#ifdef SA_RESTORER
kernel_new_action.sa_restorer = bionic_new_action->sa_restorer;
if (!(kernel_new_action.sa_flags & SA_RESTORER)) {
kernel_new_action.sa_flags |= SA_RESTORER;
kernel_new_action.sa_restorer = (kernel_new_action.sa_flags & SA_SIGINFO) ? &__restore_rt : &__restore;
}
#endif
}
return __sigaction(signal, (bionic_new_action != NULL) ? &kernel_new_action : NULL, bionic_old_action);
#endif
}