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- // 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 <stdint.h> // for uintptr_t
- #include <stdlib.h> // for NULL
- #include <gperftools/stacktrace.h>
- // 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 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<!IS_STACK_FRAMES>(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;
- }
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