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/*
* Copyright (C) 2017 The Android Open Source Project
*
* 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
*
* http://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.
*/
#include <stdint.h>
#include <sys/mman.h>
#include <memory>
#include <vector>
#include <unwindstack/Elf.h>
#include <unwindstack/JitDebug.h>
#include <unwindstack/Maps.h>
#include "MemoryRange.h"
// This implements the JIT Compilation Interface.
// See https://sourceware.org/gdb/onlinedocs/gdb/JIT-Interface.html
namespace unwindstack {
struct JITCodeEntry32Pack {
uint32_t next;
uint32_t prev;
uint32_t symfile_addr;
uint64_t symfile_size;
} __attribute__((packed));
struct JITCodeEntry32Pad {
uint32_t next;
uint32_t prev;
uint32_t symfile_addr;
uint32_t pad;
uint64_t symfile_size;
};
struct JITCodeEntry64 {
uint64_t next;
uint64_t prev;
uint64_t symfile_addr;
uint64_t symfile_size;
};
struct JITDescriptorHeader {
uint32_t version;
uint32_t action_flag;
};
struct JITDescriptor32 {
JITDescriptorHeader header;
uint32_t relevant_entry;
uint32_t first_entry;
};
struct JITDescriptor64 {
JITDescriptorHeader header;
uint64_t relevant_entry;
uint64_t first_entry;
};
JitDebug::JitDebug(std::shared_ptr<Memory>& memory) : Global(memory) {}
JitDebug::JitDebug(std::shared_ptr<Memory>& memory, std::vector<std::string>& search_libs)
: Global(memory, search_libs) {}
JitDebug::~JitDebug() {
for (auto* elf : elf_list_) {
delete elf;
}
}
uint64_t JitDebug::ReadDescriptor32(uint64_t addr) {
JITDescriptor32 desc;
if (!memory_->ReadFully(addr, &desc, sizeof(desc))) {
return 0;
}
if (desc.header.version != 1 || desc.first_entry == 0) {
// Either unknown version, or no jit entries.
return 0;
}
return desc.first_entry;
}
uint64_t JitDebug::ReadDescriptor64(uint64_t addr) {
JITDescriptor64 desc;
if (!memory_->ReadFully(addr, &desc, sizeof(desc))) {
return 0;
}
if (desc.header.version != 1 || desc.first_entry == 0) {
// Either unknown version, or no jit entries.
return 0;
}
return desc.first_entry;
}
uint64_t JitDebug::ReadEntry32Pack(uint64_t* start, uint64_t* size) {
JITCodeEntry32Pack code;
if (!memory_->ReadFully(entry_addr_, &code, sizeof(code))) {
return 0;
}
*start = code.symfile_addr;
*size = code.symfile_size;
return code.next;
}
uint64_t JitDebug::ReadEntry32Pad(uint64_t* start, uint64_t* size) {
JITCodeEntry32Pad code;
if (!memory_->ReadFully(entry_addr_, &code, sizeof(code))) {
return 0;
}
*start = code.symfile_addr;
*size = code.symfile_size;
return code.next;
}
uint64_t JitDebug::ReadEntry64(uint64_t* start, uint64_t* size) {
JITCodeEntry64 code;
if (!memory_->ReadFully(entry_addr_, &code, sizeof(code))) {
return 0;
}
*start = code.symfile_addr;
*size = code.symfile_size;
return code.next;
}
void JitDebug::ProcessArch() {
switch (arch()) {
case ARCH_X86:
read_descriptor_func_ = &JitDebug::ReadDescriptor32;
read_entry_func_ = &JitDebug::ReadEntry32Pack;
break;
case ARCH_ARM:
case ARCH_MIPS:
read_descriptor_func_ = &JitDebug::ReadDescriptor32;
read_entry_func_ = &JitDebug::ReadEntry32Pad;
break;
case ARCH_ARM64:
case ARCH_X86_64:
case ARCH_MIPS64:
read_descriptor_func_ = &JitDebug::ReadDescriptor64;
read_entry_func_ = &JitDebug::ReadEntry64;
break;
case ARCH_UNKNOWN:
abort();
}
}
bool JitDebug::ReadVariableData(uint64_t ptr) {
entry_addr_ = (this->*read_descriptor_func_)(ptr);
return entry_addr_ != 0;
}
void JitDebug::Init(Maps* maps) {
if (initialized_) {
return;
}
// Regardless of what happens below, consider the init finished.
initialized_ = true;
FindAndReadVariable(maps, "__jit_debug_descriptor");
}
Elf* JitDebug::Find(Maps* maps, uint64_t pc) {
// Use a single lock, this object should be used so infrequently that
// a fine grain lock is unnecessary.
std::lock_guard<std::mutex> guard(lock_);
if (!initialized_) {
Init(maps);
}
// Search the existing elf object first.
for (Elf* elf : elf_list_) {
if (elf->IsValidPc(pc)) {
return elf;
}
}
while (entry_addr_ != 0) {
uint64_t start;
uint64_t size;
entry_addr_ = (this->*read_entry_func_)(&start, &size);
Elf* elf = new Elf(new MemoryRange(memory_, start, size, 0));
elf->Init();
if (!elf->valid()) {
// The data is not formatted in a way we understand, do not attempt
// to process any other entries.
entry_addr_ = 0;
delete elf;
return nullptr;
}
elf_list_.push_back(elf);
if (elf->IsValidPc(pc)) {
return elf;
}
}
return nullptr;
}
} // namespace unwindstack
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