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Diffstat (limited to 'abseil-cpp/absl/debugging/internal/stacktrace_riscv-inl.inc')
| -rw-r--r-- | abseil-cpp/absl/debugging/internal/stacktrace_riscv-inl.inc | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/abseil-cpp/absl/debugging/internal/stacktrace_riscv-inl.inc b/abseil-cpp/absl/debugging/internal/stacktrace_riscv-inl.inc new file mode 100644 index 0000000..20183fa --- /dev/null +++ b/abseil-cpp/absl/debugging/internal/stacktrace_riscv-inl.inc @@ -0,0 +1,191 @@ +// Copyright 2021 The Abseil Authors +// +// 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 +// +// https://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. + +#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_RISCV_INL_H_ +#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_RISCV_INL_H_ + +// Generate stack trace for riscv + +#include <sys/ucontext.h> + +#include "absl/base/config.h" +#if defined(__linux__) +#include <sys/mman.h> +#include <ucontext.h> +#include <unistd.h> +#endif + +#include <atomic> +#include <cassert> +#include <cstdint> +#include <iostream> +#include <limits> +#include <utility> + +#include "absl/base/attributes.h" +#include "absl/debugging/stacktrace.h" + +static const uintptr_t kUnknownFrameSize = 0; + +// Compute the size of a stack frame in [low..high). We assume that low < high. +// Return size of kUnknownFrameSize. +template <typename T> +static inline uintptr_t ComputeStackFrameSize(const T *low, const T *high) { + const char *low_char_ptr = reinterpret_cast<const char *>(low); + const char *high_char_ptr = reinterpret_cast<const char *>(high); + return low < high ? high_char_ptr - low_char_ptr : kUnknownFrameSize; +} + +// 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, bool WITH_CONTEXT> +ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS // May read random elements from stack. +ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY // May read random elements from stack. +static void ** NextStackFrame(void **old_frame_pointer, const void *uc, + const std::pair<size_t, size_t> range) { + // . + // . + // . + // +-> +----------------+ + // | | return address | + // | | previous fp | + // | | ... | + // | +----------------+ <-+ + // | | return address | | + // +---|- previous fp | | + // | ... | | + // $fp ->|----------------+ | + // | return address | | + // | previous fp -|---+ + // $sp ->| ... | + // +----------------+ + void **new_frame_pointer = reinterpret_cast<void **>(old_frame_pointer[-2]); + uintptr_t frame_pointer = reinterpret_cast<uintptr_t>(new_frame_pointer); + + // The RISCV ELF psABI mandates that the stack pointer is always 16-byte + // aligned. + // TODO(#1236) this doesn't hold for ILP32E which only mandates a 4-byte + // alignment. + if (frame_pointer & 15) + return nullptr; + + // If the new frame pointer matches the signal context, avoid terminating + // early to deal with alternate signal stacks. + if (WITH_CONTEXT) + if (const ucontext_t *ucv = static_cast<const ucontext_t *>(uc)) + // RISCV ELF psABI has the frame pointer at x8/fp/s0. + // -- RISCV psABI Table 18.2 + if (ucv->uc_mcontext.__gregs[8] == frame_pointer) + return new_frame_pointer; + + // Check frame size. In strict mode, we assume frames to be under 100,000 + // bytes. In non-strict mode, we relax the limit to 1MB. + const uintptr_t max_size = STRICT_UNWINDING ? 100000 : 1000000; + const uintptr_t frame_size = + ComputeStackFrameSize(old_frame_pointer, new_frame_pointer); + if (frame_size == kUnknownFrameSize) { + if (STRICT_UNWINDING) + return nullptr; + + // In non-strict mode permit non-contiguous stacks (e.g. alternate signal + // frame handling). + if (reinterpret_cast<uintptr_t>(new_frame_pointer) < range.first || + reinterpret_cast<uintptr_t>(new_frame_pointer) > range.second) + return nullptr; + } + + if (frame_size > max_size) + return nullptr; + + return new_frame_pointer; +} + +template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT> +ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS // May read random elements from stack. +ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY // May read random elements from stack. +static int UnwindImpl(void **result, int *sizes, int max_depth, int skip_count, + const void *ucp, int *min_dropped_frames) { + // The `frame_pointer` that is computed here points to the top of the frame. + // The two words preceding the address are the return address and the previous + // frame pointer. +#if defined(__GNUC__) + void **frame_pointer = reinterpret_cast<void **>(__builtin_frame_address(0)); +#else +#error reading stack pointer not yet supported on this platform +#endif + + std::pair<size_t, size_t> stack = { + // assume that the first page is not the stack. + static_cast<size_t>(sysconf(_SC_PAGESIZE)), + std::numeric_limits<size_t>::max() - sizeof(void *) + }; + + int n = 0; + void *return_address = nullptr; + while (frame_pointer && n < max_depth) { + return_address = frame_pointer[-1]; + + // The absl::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_frame_pointer = + NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp, + stack); + + if (skip_count > 0) { + skip_count--; + } else { + result[n] = return_address; + if (IS_STACK_FRAMES) { + sizes[n] = ComputeStackFrameSize(frame_pointer, next_frame_pointer); + } + n++; + } + + frame_pointer = next_frame_pointer; + } + + if (min_dropped_frames != nullptr) { + // Implementation detail: we clamp the max of frames we are willing to + // count, so as not to spend too much time in the loop below. + const int kMaxUnwind = 200; + int num_dropped_frames = 0; + for (int j = 0; frame_pointer != nullptr && j < kMaxUnwind; j++) { + if (skip_count > 0) { + skip_count--; + } else { + num_dropped_frames++; + } + frame_pointer = + NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp, + stack); + } + *min_dropped_frames = num_dropped_frames; + } + + return n; +} + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace debugging_internal { +bool StackTraceWorksForTest() { return true; } +} // namespace debugging_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif |