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android_system_core/libunwindstack/tests/ElfInterfaceArmTest.cpp
Christopher Ferris 4cc36d2b43 Fix handling of load bias values. 
It turns out that for the dwarf information, if a FDE indicates it's pc
relative, then pc has to be incremented by the load bias. If not, then
it should not be incremented.

Previously, the code always subtracted load bias values from pcs, and assumed
that all fdes were incremented by load bias values. The new code actually
reads the fdes and adjusted the pcs in the fde and in the eh frame hdr so
that load bias values are already handled properly.

In addition, add dumping of arm exidx values in unwind_reg_info. This allowed
verifying that the debug frame in those elf files was being handled properly.

Added a new unit test that only has a debug frame that has a non-zero load
bias and has fde entries that do not have pc relative encoding.

Fix a couple of other small bugs.

Bug: 109824792

Test: All libbacktrace/libunwindstack unit tests pass.
Test: Ran ART 137-cfi test and 004-ThreadStress.
Test: Verify that displaying the fde start and end pc actually match the
Test: real data for fde that have pc relative set, and that don't.
Test: Verified that the unwind information for arm exidx matches the
Test: debug frame data.

Change-Id: I707555286b5cb05df9f25489e8c5ede753cfe0fb
2018-06-11 18:53:55 -07:00

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/*
* Copyright (C) 2016 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 <elf.h>
#include <gtest/gtest.h>
#include <vector>
#include <unwindstack/MachineArm.h>
#include <unwindstack/RegsArm.h>
#include "ElfInterfaceArm.h"
#include "ElfFake.h"
#include "MemoryFake.h"
namespace unwindstack {
class ElfInterfaceArmTest : public ::testing::Test {
protected:
void SetUp() override {
memory_.Clear();
process_memory_.Clear();
}
MemoryFake memory_;
MemoryFake process_memory_;
};
TEST_F(ElfInterfaceArmTest, GetPrel32Addr) {
ElfInterfaceArmFake interface(&memory_);
memory_.SetData32(0x1000, 0x230000);
uint32_t value;
ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
ASSERT_EQ(0x231000U, value);
memory_.SetData32(0x1000, 0x80001000);
ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
ASSERT_EQ(0x2000U, value);
memory_.SetData32(0x1000, 0x70001000);
ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
ASSERT_EQ(0xf0002000U, value);
}
TEST_F(ElfInterfaceArmTest, FindEntry_start_zero) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0);
interface.FakeSetTotalEntries(10);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_no_entries) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x100);
interface.FakeSetTotalEntries(0);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_no_valid_memory) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x100);
interface.FakeSetTotalEntries(2);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_ip_before_first) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(1);
memory_.SetData32(0x1000, 0x6000);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_single_entry_negative_value) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x8000);
interface.FakeSetTotalEntries(1);
memory_.SetData32(0x8000, 0x7fffff00);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x7ff0, &entry_offset));
ASSERT_EQ(0x8000U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_two_entries) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x7000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x7000, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_last_check_single_entry) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(1);
memory_.SetData32(0x1000, 0x6000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x7000, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x8000);
ASSERT_TRUE(interface.FindEntry(0x7004, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_last_check_multiple_entries) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x8000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x9008, &entry_offset));
ASSERT_EQ(0x1008U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x16000);
memory_.SetData32(0x1008, 0x18000);
ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
ASSERT_EQ(0x1008U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_multiple_entries_even) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(4);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x7000);
memory_.SetData32(0x1010, 0x8000);
memory_.SetData32(0x1018, 0x9000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x16000);
memory_.SetData32(0x1008, 0x17000);
memory_.SetData32(0x1010, 0x18000);
memory_.SetData32(0x1018, 0x19000);
ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_multiple_entries_odd) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(5);
memory_.SetData32(0x1000, 0x5000);
memory_.SetData32(0x1008, 0x6000);
memory_.SetData32(0x1010, 0x7000);
memory_.SetData32(0x1018, 0x8000);
memory_.SetData32(0x1020, 0x9000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x8100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x15000);
memory_.SetData32(0x1008, 0x16000);
memory_.SetData32(0x1010, 0x17000);
memory_.SetData32(0x1018, 0x18000);
memory_.SetData32(0x1020, 0x19000);
ASSERT_TRUE(interface.FindEntry(0x8100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, iterate) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(5);
memory_.SetData32(0x1000, 0x5000);
memory_.SetData32(0x1008, 0x6000);
memory_.SetData32(0x1010, 0x7000);
memory_.SetData32(0x1018, 0x8000);
memory_.SetData32(0x1020, 0x9000);
std::vector<uint32_t> entries;
for (auto addr : interface) {
entries.push_back(addr);
}
ASSERT_EQ(5U, entries.size());
ASSERT_EQ(0x6000U, entries[0]);
ASSERT_EQ(0x7008U, entries[1]);
ASSERT_EQ(0x8010U, entries[2]);
ASSERT_EQ(0x9018U, entries[3]);
ASSERT_EQ(0xa020U, entries[4]);
// Make sure the iterate cached the entries.
memory_.SetData32(0x1000, 0x11000);
memory_.SetData32(0x1008, 0x12000);
memory_.SetData32(0x1010, 0x13000);
memory_.SetData32(0x1018, 0x14000);
memory_.SetData32(0x1020, 0x15000);
entries.clear();
for (auto addr : interface) {
entries.push_back(addr);
}
ASSERT_EQ(5U, entries.size());
ASSERT_EQ(0x6000U, entries[0]);
ASSERT_EQ(0x7008U, entries[1]);
ASSERT_EQ(0x8010U, entries[2]);
ASSERT_EQ(0x9018U, entries[3]);
ASSERT_EQ(0xa020U, entries[4]);
}
TEST_F(ElfInterfaceArmTest, HandleType_not_arm_exidx) {
ElfInterfaceArmFake interface(&memory_);
ASSERT_FALSE(interface.HandleType(0x1000, PT_NULL, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_LOAD, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_DYNAMIC, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_INTERP, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_NOTE, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_SHLIB, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_PHDR, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_TLS, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_LOOS, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_HIOS, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_LOPROC, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_HIPROC, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_GNU_EH_FRAME, 0));
ASSERT_FALSE(interface.HandleType(0x1000, PT_GNU_STACK, 0));
}
TEST_F(ElfInterfaceArmTest, HandleType_arm_exidx) {
ElfInterfaceArmFake interface(&memory_);
Elf32_Phdr phdr;
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(100);
phdr.p_vaddr = 0x2000;
phdr.p_memsz = 0xa00;
// Verify that if reads fail, we don't set the values but still get true.
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001, 0));
ASSERT_EQ(0x1000U, interface.start_offset());
ASSERT_EQ(100U, interface.total_entries());
// Verify that if the second read fails, we still don't set the values.
memory_.SetData32(
0x1000 + reinterpret_cast<uint64_t>(&phdr.p_vaddr) - reinterpret_cast<uint64_t>(&phdr),
phdr.p_vaddr);
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001, 0));
ASSERT_EQ(0x1000U, interface.start_offset());
ASSERT_EQ(100U, interface.total_entries());
// Everything is correct and present.
memory_.SetData32(
0x1000 + reinterpret_cast<uint64_t>(&phdr.p_memsz) - reinterpret_cast<uint64_t>(&phdr),
phdr.p_memsz);
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001, 0));
ASSERT_EQ(0x2000U, interface.start_offset());
ASSERT_EQ(320U, interface.total_entries());
// Non-zero load bias.
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001, 0x1000));
ASSERT_EQ(0x1000U, interface.start_offset());
ASSERT_EQ(320U, interface.total_entries());
}
TEST_F(ElfInterfaceArmTest, StepExidx) {
ElfInterfaceArmFake interface(&memory_);
// FindEntry fails.
bool finished;
ASSERT_FALSE(interface.StepExidx(0x7000, nullptr, nullptr, &finished));
EXPECT_EQ(ERROR_UNWIND_INFO, interface.LastErrorCode());
// ExtractEntry should fail.
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x8000);
RegsArm regs;
regs[ARM_REG_SP] = 0x1000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
ASSERT_FALSE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_MEMORY_INVALID, interface.LastErrorCode());
EXPECT_EQ(0x1004U, interface.LastErrorAddress());
// Eval should fail.
memory_.SetData32(0x1004, 0x81000000);
ASSERT_FALSE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_UNWIND_INFO, interface.LastErrorCode());
// Everything should pass.
memory_.SetData32(0x1004, 0x80b0b0b0);
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_UNWIND_INFO, interface.LastErrorCode());
ASSERT_FALSE(finished);
ASSERT_EQ(0x1000U, regs.sp());
ASSERT_EQ(0x1000U, regs[ARM_REG_SP]);
ASSERT_EQ(0x20000U, regs.pc());
ASSERT_EQ(0x20000U, regs[ARM_REG_PC]);
// Load bias is non-zero.
interface.set_load_bias(0x1000);
ASSERT_TRUE(interface.StepExidx(0x8000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_UNWIND_INFO, interface.LastErrorCode());
// Pc too small.
interface.set_load_bias(0x9000);
ASSERT_FALSE(interface.StepExidx(0x8000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_UNWIND_INFO, interface.LastErrorCode());
}
TEST_F(ElfInterfaceArmTest, StepExidx_pc_set) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1004, 0x808800b0);
memory_.SetData32(0x1008, 0x8000);
process_memory_.SetData32(0x10000, 0x10);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
// Everything should pass.
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_NONE, interface.LastErrorCode());
ASSERT_FALSE(finished);
ASSERT_EQ(0x10004U, regs.sp());
ASSERT_EQ(0x10004U, regs[ARM_REG_SP]);
ASSERT_EQ(0x10U, regs.pc());
ASSERT_EQ(0x10U, regs[ARM_REG_PC]);
}
TEST_F(ElfInterfaceArmTest, StepExidx_cant_unwind) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(1);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1004, 1);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_NONE, interface.LastErrorCode());
ASSERT_TRUE(finished);
ASSERT_EQ(0x10000U, regs.sp());
ASSERT_EQ(0x10000U, regs[ARM_REG_SP]);
ASSERT_EQ(0x1234U, regs.pc());
}
TEST_F(ElfInterfaceArmTest, StepExidx_refuse_unwind) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(1);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1004, 0x808000b0);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_NONE, interface.LastErrorCode());
ASSERT_TRUE(finished);
ASSERT_EQ(0x10000U, regs.sp());
ASSERT_EQ(0x10000U, regs[ARM_REG_SP]);
ASSERT_EQ(0x1234U, regs.pc());
}
TEST_F(ElfInterfaceArmTest, StepExidx_pc_zero) {
ElfInterfaceArmFake interface(&memory_);
interface.FakeSetStartOffset(0x1000);
interface.FakeSetTotalEntries(1);
memory_.SetData32(0x1000, 0x6000);
// Set the pc using a pop r15 command.
memory_.SetData32(0x1004, 0x808800b0);
// pc value of zero.
process_memory_.SetData32(0x10000, 0);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_NONE, interface.LastErrorCode());
ASSERT_TRUE(finished);
ASSERT_EQ(0U, regs.pc());
// Now set the pc from the lr register (pop r14).
memory_.SetData32(0x1004, 0x808400b0);
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
EXPECT_EQ(ERROR_NONE, interface.LastErrorCode());
ASSERT_TRUE(finished);
ASSERT_EQ(0U, regs.pc());
}
} // namespace unwindstack
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