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// Copyright 2018 Google LLC
//
// 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 <signal.h>
#include "gtest/gtest.h"
#include "test/util/logging.h"
#include "test/util/signal_util.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
void inline Halt() { asm("hlt\r\n"); }
void inline SetAlignmentCheck() {
asm("subq $128, %%rsp\r\n" // Avoid potential red zone clobber
"pushf\r\n"
"pop %%rax\r\n"
"or $0x40000, %%rax\r\n"
"push %%rax\r\n"
"popf\r\n"
"addq $128, %%rsp\r\n"
:
:
: "ax");
}
void inline ClearAlignmentCheck() {
asm("subq $128, %%rsp\r\n" // Avoid potential red zone clobber
"pushf\r\n"
"pop %%rax\r\n"
"mov $0x40000, %%rbx\r\n"
"not %%rbx\r\n"
"and %%rbx, %%rax\r\n"
"push %%rax\r\n"
"popf\r\n"
"addq $128, %%rsp\r\n"
:
:
: "ax", "bx");
}
void inline Int3Normal() { asm(".byte 0xcd, 0x03\r\n"); }
void inline Int3Compact() { asm(".byte 0xcc\r\n"); }
TEST(ExceptionTest, Halt) {
// In order to prevent the regular handler from messing with things (and
// perhaps refaulting until some other signal occurs), we reset the handler to
// the default action here and ensure that it dies correctly.
struct sigaction sa = {};
sa.sa_handler = SIG_DFL;
auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGSEGV, sa));
EXPECT_EXIT(Halt(), ::testing::KilledBySignal(SIGSEGV), "");
}
TEST(ExceptionTest, DivideByZero) {
// See above.
struct sigaction sa = {};
sa.sa_handler = SIG_DFL;
auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGFPE, sa));
EXPECT_EXIT(
{
uint32_t remainder;
uint32_t quotient;
uint32_t divisor = 0;
uint64_t value = 1;
asm("divl 0(%2)\r\n"
: "=d"(remainder), "=a"(quotient)
: "r"(&divisor), "d"(value >> 32), "a"(value));
TEST_CHECK(quotient > 0); // Force dependency.
},
::testing::KilledBySignal(SIGFPE), "");
}
TEST(ExceptionTest, Alignment) {
SetAlignmentCheck();
ClearAlignmentCheck();
}
TEST(ExceptionTest, AlignmentHalt) {
// See above.
struct sigaction sa = {};
sa.sa_handler = SIG_DFL;
auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGSEGV, sa));
// Reported upstream. We need to ensure that bad flags are cleared even in
// fault paths. Set the alignment flag and then generate an exception.
EXPECT_EXIT(
{
SetAlignmentCheck();
Halt();
},
::testing::KilledBySignal(SIGSEGV), "");
}
TEST(ExceptionTest, AlignmentCheck) {
// See above.
struct sigaction sa = {};
sa.sa_handler = SIG_DFL;
auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGBUS, sa));
EXPECT_EXIT(
{
char array[16];
SetAlignmentCheck();
for (int i = 0; i < 8; i++) {
// At least 7/8 offsets will be unaligned here.
uint64_t* ptr = reinterpret_cast<uint64_t*>(&array[i]);
asm("mov %0, 0(%0)\r\n" : : "r"(ptr) : "ax");
}
},
::testing::KilledBySignal(SIGBUS), "");
}
TEST(ExceptionTest, Int3Normal) {
// See above.
struct sigaction sa = {};
sa.sa_handler = SIG_DFL;
auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGTRAP, sa));
EXPECT_EXIT(Int3Normal(), ::testing::KilledBySignal(SIGTRAP), "");
}
TEST(ExceptionTest, Int3Compact) {
// See above.
struct sigaction sa = {};
sa.sa_handler = SIG_DFL;
auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGTRAP, sa));
EXPECT_EXIT(Int3Compact(), ::testing::KilledBySignal(SIGTRAP), "");
}
} // namespace testing
} // namespace gvisor
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