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.
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 @@
#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-inl.h b/src/stacktrace_powerpc-darwin-inl.h
similarity index 60%
copy from src/stacktrace_powerpc-inl.h
copy to src/stacktrace_powerpc-darwin-inl.h
index 811d6cc..c4c2edb 100644
--- a/src/stacktrace_powerpc-inl.h
+++ b/src/stacktrace_powerpc-darwin-inl.h
@@ -1,11 +1,10 @@
-// -*- 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
@@ -15,7 +14,7 @@
// * 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
@@ -29,13 +28,11 @@
// 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
+// 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_
@@ -46,45 +43,32 @@
#include <stdlib.h> // for NULL
#include <gperftools/stacktrace.h>
-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<bool STRICT_UNWINDING>
-static layout_ppc *NextStackFrame(layout_ppc *current) {
- uintptr_t old_sp = (uintptr_t)(current);
- uintptr_t new_sp = (uintptr_t)(current->next);
+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;
+ 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;
+ 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;
+ 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 > old_sp)
+ && ((uintptr_t)new_sp - (uintptr_t)old_sp > 1000000)) return NULL;
}
- if (new_sp & (sizeof(void *) - 1))
- return NULL;
- return current->next;
+ if ((uintptr_t)new_sp & (sizeof(void *) - 1)) return NULL;
+ return new_sp;
}
// This ensures that GetStackTrace stes up the Link Register properly.
@@ -95,26 +79,6 @@
// 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()
@@ -126,36 +90,61 @@
// 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;
+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));
- // Force GCC to spill LR.
- asm volatile ("" : "=l"(current));
-
- // Get the address on top-of-stack
- asm volatile (LOAD " " TOP_STACK : "=r"(current));
-
+ // 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();
- n = 0;
- skip_count++; // skip parent's frame due to indirection in
- // stacktrace.cc
- while (current && n < max_depth) {
+#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).
- layout_ppc *next = NextStackFrame<!IS_STACK_FRAMES>(current);
+ void **next_sp = NextStackFrame<!IS_STACK_FRAMES>(sp);
+
if (skip_count > 0) {
skip_count--;
} else {
- result[n] = current->return_addr;
+ // 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 > current) {
- sizes[n] = (uintptr_t)next - (uintptr_t)current;
+ 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;
@@ -163,14 +152,7 @@
#endif
n++;
}
- current = next;
+ sp = next_sp;
}
-
- // 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-inl.h b/src/stacktrace_powerpc-linux-inl.h
similarity index 63%
rename from src/stacktrace_powerpc-inl.h
rename to src/stacktrace_powerpc-linux-inl.h
index 811d6cc..5d16fa1 100644
--- a/src/stacktrace_powerpc-inl.h
+++ b/src/stacktrace_powerpc-linux-inl.h
@@ -1,11 +1,11 @@
// -*- 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
@@ -15,7 +15,7 @@
// * 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
@@ -31,11 +31,11 @@
// ---
// 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
+// 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_
@@ -45,15 +45,36 @@
#include <stdint.h> // for uintptr_t
#include <stdlib.h> // for NULL
#include <gperftools/stacktrace.h>
+#include <base/vdso_support.h>
+#if defined(HAVE_SYS_UCONTEXT_H)
+#include <sys/ucontext.h>
+#elif defined(HAVE_UCONTEXT_H)
+#include <ucontext.h> // 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;
-#if defined(__APPLE__) || (defined(__linux) && defined(__PPC64__))
+#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
@@ -102,19 +123,6 @@
# 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()
@@ -130,17 +138,35 @@
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));
+ current = reinterpret_cast<layout_ppc*> (__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
@@ -153,6 +179,35 @@
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<signal_frame_64*>(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<signal_frame_32*>(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<rt_signal_frame_32*>(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;
