From b8c4ba72969562d1378002aa03c6097fa6f8cbec Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 2 Apr 2014 06:46:53 -0500 Subject: PowerPC: stacktrace function refactor and fixes This patch fixes the stacktrace creating when the function is interrupted by a signal. For Linux, the vDSO signal trampoline symbol is compared against LR from stack backchain and handled different in that case (since the signal trampoline layout a different stack frame). Because of this extensive change the PowerPC stacktrace code has now been refactored to split in Linux and Darwin specific codes. --- src/stacktrace.cc | 6 +- src/stacktrace_powerpc-darwin-inl.h | 158 ++++++++++++++++++++++++ src/stacktrace_powerpc-inl.h | 176 --------------------------- src/stacktrace_powerpc-linux-inl.h | 231 ++++++++++++++++++++++++++++++++++++ 4 files changed, 394 insertions(+), 177 deletions(-) create mode 100644 src/stacktrace_powerpc-darwin-inl.h delete mode 100644 src/stacktrace_powerpc-inl.h create mode 100644 src/stacktrace_powerpc-linux-inl.h diff --git a/src/stacktrace.cc b/src/stacktrace.cc index df9630a..549b252 100644 --- a/src/stacktrace.cc +++ b/src/stacktrace.cc @@ -109,7 +109,11 @@ struct GetStackImplementation { #endif // i386 || x86_64 #if defined(__ppc__) || defined(__PPC__) -#define STACKTRACE_INL_HEADER "stacktrace_powerpc-inl.h" +#if defined(__linux__) +#define STACKTRACE_INL_HEADER "stacktrace_powerpc-linux-inl.h" +#else +#define STACKTRACE_INL_HEADER "stacktrace_powerpc-darwin-inl.h" +#endif #define GST_SUFFIX ppc #include "stacktrace_impl_setup-inl.h" #undef GST_SUFFIX diff --git a/src/stacktrace_powerpc-darwin-inl.h b/src/stacktrace_powerpc-darwin-inl.h new file mode 100644 index 0000000..c4c2edb --- /dev/null +++ b/src/stacktrace_powerpc-darwin-inl.h @@ -0,0 +1,158 @@ +// Copyright (c) 2007, 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. + +// --- +// Produce stack trace. ABI documentation reference can be found at: +// * PowerPC32 ABI: https://www.power.org/documentation/ +// power-architecture-32-bit-abi-supplement-1-0-embeddedlinuxunified/ +// * PowerPC64 ABI: +// http://www.linux-foundation.org/spec/ELF/ppc64/PPC-elf64abi-1.9.html#STACK + +#ifndef BASE_STACKTRACE_POWERPC_INL_H_ +#define BASE_STACKTRACE_POWERPC_INL_H_ +// Note: this file is included into stacktrace.cc more than once. +// Anything that should only be defined once should be here: + +#include // for uintptr_t +#include // for NULL +#include + +// Given a pointer to a stack frame, locate and return the calling +// stackframe, or return NULL if no stackframe can be found. Perform sanity +// checks (the strictness of which is controlled by the boolean parameter +// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned. +template +static void **NextStackFrame(void **old_sp) { + void **new_sp = (void **) *old_sp; + + // Check that the transition from frame pointer old_sp to frame + // pointer new_sp isn't clearly bogus + if (STRICT_UNWINDING) { + // With the stack growing downwards, older stack frame must be + // at a greater address that the current one. + if (new_sp <= old_sp) return NULL; + // Assume stack frames larger than 100,000 bytes are bogus. + if ((uintptr_t)new_sp - (uintptr_t)old_sp > 100000) return NULL; + } else { + // In the non-strict mode, allow discontiguous stack frames. + // (alternate-signal-stacks for example). + if (new_sp == old_sp) return NULL; + // And allow frames upto about 1MB. + if ((new_sp > old_sp) + && ((uintptr_t)new_sp - (uintptr_t)old_sp > 1000000)) return NULL; + } + if ((uintptr_t)new_sp & (sizeof(void *) - 1)) return NULL; + return new_sp; +} + +// This ensures that GetStackTrace stes up the Link Register properly. +void StacktracePowerPCDummyFunction() __attribute__((noinline)); +void StacktracePowerPCDummyFunction() { __asm__ volatile(""); } +#endif // BASE_STACKTRACE_POWERPC_INL_H_ + +// Note: this part of the file is included several times. +// Do not put globals below. + +// The following 4 functions are generated from the code below: +// GetStack{Trace,Frames}() +// GetStack{Trace,Frames}WithContext() +// +// These functions take the following args: +// void** result: the stack-trace, as an array +// int* sizes: the size of each stack frame, as an array +// (GetStackFrames* only) +// int max_depth: the size of the result (and sizes) array(s) +// int skip_count: how many stack pointers to skip before storing in result +// void* ucp: a ucontext_t* (GetStack{Trace,Frames}WithContext only) +int GET_STACK_TRACE_OR_FRAMES { + void **sp; + // Apple OS X uses an old version of gnu as -- both Darwin 7.9.0 (Panther) + // and Darwin 8.8.1 (Tiger) use as 1.38. This means we have to use a + // different asm syntax. I don't know quite the best way to discriminate + // systems using the old as from the new one; I've gone with __APPLE__. + // TODO(csilvers): use autoconf instead, to look for 'as --version' == 1 or 2 + __asm__ volatile ("mr %0,r1" : "=r" (sp)); + + // On PowerPC, the "Link Register" or "Link Record" (LR), is a stack + // entry that holds the return address of the subroutine call (what + // instruction we run after our function finishes). This is the + // same as the stack-pointer of our parent routine, which is what we + // want here. While the compiler will always(?) set up LR for + // subroutine calls, it may not for leaf functions (such as this one). + // This routine forces the compiler (at least gcc) to push it anyway. + StacktracePowerPCDummyFunction(); + +#if IS_STACK_FRAMES + // Note we do *not* increment skip_count here for the SYSV ABI. If + // we did, the list of stack frames wouldn't properly match up with + // the list of return addresses. Note this means the top pc entry + // is probably bogus for linux/ppc (and other SYSV-ABI systems). +#else + // The LR save area is used by the callee, so the top entry is bogus. + skip_count++; +#endif + + int n = 0; + while (sp && n < max_depth) { + // The GetStackFrames routine is called when we are in some + // informational context (the failure signal handler for example). + // Use the non-strict unwinding rules to produce a stack trace + // that is as complete as possible (even if it contains a few + // bogus entries in some rare cases). + void **next_sp = NextStackFrame(sp); + + if (skip_count > 0) { + skip_count--; + } else { + // PowerPC has 3 main ABIs, which say where in the stack the + // Link Register is. For DARWIN and AIX (used by apple and + // linux ppc64), it's in sp[2]. For SYSV (used by linux ppc), + // it's in sp[1]. +#if defined(__PPC64__) + // This check is in case the compiler doesn't define _CALL_AIX/etc. + result[n] = *(sp+2); +#elif defined(__linux) + // This check is in case the compiler doesn't define _CALL_SYSV. + result[n] = *(sp+1); +#endif + +#if IS_STACK_FRAMES + if (next_sp > sp) { + sizes[n] = (uintptr_t)next_sp - (uintptr_t)sp; + } else { + // A frame-size of 0 is used to indicate unknown frame size. + sizes[n] = 0; + } +#endif + n++; + } + sp = next_sp; + } + return n; +} diff --git a/src/stacktrace_powerpc-inl.h b/src/stacktrace_powerpc-inl.h deleted file mode 100644 index 811d6cc..0000000 --- a/src/stacktrace_powerpc-inl.h +++ /dev/null @@ -1,176 +0,0 @@ -// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- -// Copyright (c) 2007, 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. - -// --- -// Author: Craig Silverstein -// -// Produce stack trace. I'm guessing (hoping!) the code is much like -// for x86. For apple machines, at least, it seems to be; see -// http://developer.apple.com/documentation/mac/runtimehtml/RTArch-59.html -// http://www.linux-foundation.org/spec/ELF/ppc64/PPC-elf64abi-1.9.html#STACK -// Linux has similar code: http://patchwork.ozlabs.org/linuxppc/patch?id=8882 - -#ifndef BASE_STACKTRACE_POWERPC_INL_H_ -#define BASE_STACKTRACE_POWERPC_INL_H_ -// Note: this file is included into stacktrace.cc more than once. -// Anything that should only be defined once should be here: - -#include // for uintptr_t -#include // for NULL -#include - -struct layout_ppc { - struct layout_ppc *next; -#if defined(__APPLE__) || (defined(__linux) && defined(__PPC64__)) - long condition_register; -#endif - void *return_addr; -}; - -// Given a pointer to a stack frame, locate and return the calling -// stackframe, or return NULL if no stackframe can be found. Perform sanity -// checks (the strictness of which is controlled by the boolean parameter -// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned. -template -static layout_ppc *NextStackFrame(layout_ppc *current) { - uintptr_t old_sp = (uintptr_t)(current); - uintptr_t new_sp = (uintptr_t)(current->next); - - // Check that the transition from frame pointer old_sp to frame - // pointer new_sp isn't clearly bogus - if (STRICT_UNWINDING) { - // With the stack growing downwards, older stack frame must be - // at a greater address that the current one. - if (new_sp <= old_sp) - return NULL; - // Assume stack frames larger than 100,000 bytes are bogus. - if (new_sp - old_sp > 100000) - return NULL; - } else { - // In the non-strict mode, allow discontiguous stack frames. - // (alternate-signal-stacks for example). - if (new_sp == old_sp) - return NULL; - // And allow frames upto about 1MB. - if ((new_sp > old_sp) && (new_sp - old_sp > 1000000)) - return NULL; - } - if (new_sp & (sizeof(void *) - 1)) - return NULL; - return current->next; -} - -// This ensures that GetStackTrace stes up the Link Register properly. -void StacktracePowerPCDummyFunction() __attribute__((noinline)); -void StacktracePowerPCDummyFunction() { __asm__ volatile(""); } -#endif // BASE_STACKTRACE_POWERPC_INL_H_ - -// Note: this part of the file is included several times. -// Do not put globals below. - -// Load instruction used on top-of-stack get. -#if defined(__PPC64__) || defined(__LP64__) -# define LOAD "ld" -#else -# define LOAD "lwz" -#endif - -#if defined(__linux__) && defined(__PPC__) -# define TOP_STACK "%0,0(1)" -#elif defined(__MACH__) && defined(__APPLE__) -// Apple OS X uses an old version of gnu as -- both Darwin 7.9.0 (Panther) -// and Darwin 8.8.1 (Tiger) use as 1.38. This means we have to use a -// different asm syntax. I don't know quite the best way to discriminate -// systems using the old as from the new one; I've gone with __APPLE__. -// TODO(csilvers): use autoconf instead, to look for 'as --version' == 1 or 2 -# define TOP_STACK "%0,0(r1)" -#endif - - - -// The following 4 functions are generated from the code below: -// GetStack{Trace,Frames}() -// GetStack{Trace,Frames}WithContext() -// -// These functions take the following args: -// void** result: the stack-trace, as an array -// int* sizes: the size of each stack frame, as an array -// (GetStackFrames* only) -// int max_depth: the size of the result (and sizes) array(s) -// int skip_count: how many stack pointers to skip before storing in result -// void* ucp: a ucontext_t* (GetStack{Trace,Frames}WithContext only) -static int GET_STACK_TRACE_OR_FRAMES { - layout_ppc *current; - int n; - - // Force GCC to spill LR. - asm volatile ("" : "=l"(current)); - - // Get the address on top-of-stack - asm volatile (LOAD " " TOP_STACK : "=r"(current)); - - StacktracePowerPCDummyFunction(); - - n = 0; - skip_count++; // skip parent's frame due to indirection in - // stacktrace.cc - while (current && n < max_depth) { - - // The GetStackFrames routine is called when we are in some - // informational context (the failure signal handler for example). - // Use the non-strict unwinding rules to produce a stack trace - // that is as complete as possible (even if it contains a few - // bogus entries in some rare cases). - layout_ppc *next = NextStackFrame(current); - if (skip_count > 0) { - skip_count--; - } else { - result[n] = current->return_addr; -#if IS_STACK_FRAMES - if (next > current) { - sizes[n] = (uintptr_t)next - (uintptr_t)current; - } else { - // A frame-size of 0 is used to indicate unknown frame size. - sizes[n] = 0; - } -#endif - n++; - } - current = next; - } - - // It's possible the second-last stack frame can't return - // (that is, it's __libc_start_main), in which case - // the CRT startup code will have set its LR to 'NULL'. - if (n > 0 && result[n-1] == NULL) - n--; - - return n; -} diff --git a/src/stacktrace_powerpc-linux-inl.h b/src/stacktrace_powerpc-linux-inl.h new file mode 100644 index 0000000..5d16fa1 --- /dev/null +++ b/src/stacktrace_powerpc-linux-inl.h @@ -0,0 +1,231 @@ +// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- +// Copyright (c) 2007, 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. + +// --- +// Author: Craig Silverstein +// +// Produce stack trace. ABI documentation reference can be found at: +// * PowerPC32 ABI: https://www.power.org/documentation/ +// power-architecture-32-bit-abi-supplement-1-0-embeddedlinuxunified/ +// * PowerPC64 ABI: +// http://www.linux-foundation.org/spec/ELF/ppc64/PPC-elf64abi-1.9.html#STACK + +#ifndef BASE_STACKTRACE_POWERPC_INL_H_ +#define BASE_STACKTRACE_POWERPC_INL_H_ +// Note: this file is included into stacktrace.cc more than once. +// Anything that should only be defined once should be here: + +#include // for uintptr_t +#include // for NULL +#include +#include + +#if defined(HAVE_SYS_UCONTEXT_H) +#include +#elif defined(HAVE_UCONTEXT_H) +#include // for ucontext_t +#endif +typedef ucontext ucontext_t; + +// PowerPC64 Little Endian follows BE wrt. backchain, condition register, +// and LR save area, so no need to adjust the reading struct. +struct layout_ppc { + struct layout_ppc *next; +#ifdef __PPC64__ + long condition_register; +#endif + void *return_addr; +}; + +// Signal callbacks are handled by the vDSO symbol: +// +// * PowerPC64 Linux (arch/powerpc/kernel/vdso64/sigtramp.S): +// __kernel_sigtramp_rt64 +// * PowerPC32 Linux (arch/powerpc/kernel/vdso32/sigtramp.S): +// __kernel_sigtramp32 +// __kernel_sigtramp_rt32 +// +// So a backtrace may need to specially handling if the symbol readed is +// the signal trampoline. + +// Given a pointer to a stack frame, locate and return the calling +// stackframe, or return NULL if no stackframe can be found. Perform sanity +// checks (the strictness of which is controlled by the boolean parameter +// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned. +template +static layout_ppc *NextStackFrame(layout_ppc *current) { + uintptr_t old_sp = (uintptr_t)(current); + uintptr_t new_sp = (uintptr_t)(current->next); + + // Check that the transition from frame pointer old_sp to frame + // pointer new_sp isn't clearly bogus + if (STRICT_UNWINDING) { + // With the stack growing downwards, older stack frame must be + // at a greater address that the current one. + if (new_sp <= old_sp) + return NULL; + // Assume stack frames larger than 100,000 bytes are bogus. + if (new_sp - old_sp > 100000) + return NULL; + } else { + // In the non-strict mode, allow discontiguous stack frames. + // (alternate-signal-stacks for example). + if (new_sp == old_sp) + return NULL; + // And allow frames upto about 1MB. + if ((new_sp > old_sp) && (new_sp - old_sp > 1000000)) + return NULL; + } + if (new_sp & (sizeof(void *) - 1)) + return NULL; + return current->next; +} + +// This ensures that GetStackTrace stes up the Link Register properly. +void StacktracePowerPCDummyFunction() __attribute__((noinline)); +void StacktracePowerPCDummyFunction() { __asm__ volatile(""); } +#endif // BASE_STACKTRACE_POWERPC_INL_H_ + +// Note: this part of the file is included several times. +// Do not put globals below. + +// Load instruction used on top-of-stack get. +#if defined(__PPC64__) || defined(__LP64__) +# define LOAD "ld" +#else +# define LOAD "lwz" +#endif + +// The following 4 functions are generated from the code below: +// GetStack{Trace,Frames}() +// GetStack{Trace,Frames}WithContext() +// +// These functions take the following args: +// void** result: the stack-trace, as an array +// int* sizes: the size of each stack frame, as an array +// (GetStackFrames* only) +// int max_depth: the size of the result (and sizes) array(s) +// int skip_count: how many stack pointers to skip before storing in result +// void* ucp: a ucontext_t* (GetStack{Trace,Frames}WithContext only) +static int GET_STACK_TRACE_OR_FRAMES { + layout_ppc *current; + int n; + + // Get the address on top-of-stack + current = reinterpret_cast (__builtin_frame_address (0)); + // And ignore the current symbol + current = current->next; + + StacktracePowerPCDummyFunction(); + + n = 0; + skip_count++; // skip parent's frame due to indirection in + // stacktrace.cc + + base::VDSOSupport vdso; + base::ElfMemImage::SymbolInfo rt_sigreturn_symbol_info; +#ifdef __PPC64__ + const void *sigtramp64_vdso = 0; + if (vdso.LookupSymbol("__kernel_sigtramp_rt64", "LINUX_2.6.15", STT_NOTYPE, + &rt_sigreturn_symbol_info)) + sigtramp64_vdso = rt_sigreturn_symbol_info.address; +#else + const void *sigtramp32_vdso = 0; + if (vdso.LookupSymbol("__kernel_sigtramp32", "LINUX_2.6.15", STT_NOTYPE, + &rt_sigreturn_symbol_info)) + sigtramp32_vdso = rt_sigreturn_symbol_info.address; + const void *sigtramp32_rt_vdso = 0; + if (vdso.LookupSymbol("__kernel_sigtramp_rt32", "LINUX_2.6.15", STT_NOTYPE, + &rt_sigreturn_symbol_info)) + sigtramp32_rt_vdso = rt_sigreturn_symbol_info.address; +#endif + + while (current && n < max_depth) { + + // The GetStackFrames routine is called when we are in some + // informational context (the failure signal handler for example). + // Use the non-strict unwinding rules to produce a stack trace + // that is as complete as possible (even if it contains a few + // bogus entries in some rare cases). + layout_ppc *next = NextStackFrame(current); + if (skip_count > 0) { + skip_count--; + } else { + result[n] = current->return_addr; +#ifdef __PPC64__ + if (sigtramp64_vdso && (sigtramp64_vdso == current->return_addr)) { + struct signal_frame_64 { + char dummy[128]; + ucontext_t uc; + // We don't care about the rest, since the IP value is at 'uc' field. + } *sigframe = reinterpret_cast(current); + result[n] = (void*) sigframe->uc.uc_mcontext.gp_regs[PT_NIP]; + } +#else + if (sigtramp32_vdso && (sigtramp32_vdso == current->return_addr)) { + struct signal_frame_32 { + char dummy[64]; + struct sigcontext sctx; + mcontext_t mctx; + // We don't care about the rest, since IP value is at 'mctx' field. + } *sigframe = reinterpret_cast(current); + result[n] = (void*) sigframe->mctx.gregs[PT_NIP]; + } else if (sigtramp32_rt_vdso && (sigtramp32_rt_vdso == current->return_addr)) { + struct rt_signal_frame_32 { + char dummy[64 + 16]; + siginfo_t info; + struct ucontext uc; + // We don't care about the rest, since IP value is at 'uc' field.A + } *sigframe = reinterpret_cast(current); + result[n] = (void*) sigframe->uc.uc_mcontext.uc_regs->gregs[PT_NIP]; + } +#endif + +#if IS_STACK_FRAMES + if (next > current) { + sizes[n] = (uintptr_t)next - (uintptr_t)current; + } else { + // A frame-size of 0 is used to indicate unknown frame size. + sizes[n] = 0; + } +#endif + n++; + } + current = next; + } + + // It's possible the second-last stack frame can't return + // (that is, it's __libc_start_main), in which case + // the CRT startup code will have set its LR to 'NULL'. + if (n > 0 && result[n-1] == NULL) + n--; + + return n; +} -- cgit v1.2.1