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Diffstat (limited to 'test/syscalls/linux/exceptions.cc')
| -rw-r--r-- | test/syscalls/linux/exceptions.cc | 365 |
1 files changed, 0 insertions, 365 deletions
diff --git a/test/syscalls/linux/exceptions.cc b/test/syscalls/linux/exceptions.cc deleted file mode 100644 index 3d564e720..000000000 --- a/test/syscalls/linux/exceptions.cc +++ /dev/null @@ -1,365 +0,0 @@ -// Copyright 2018 The gVisor 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 -// -// 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 { - -// Default value for the x87 FPU control word. See Intel SDM Vol 1, Ch 8.1.5 -// "x87 FPU Control Word". -constexpr uint16_t kX87ControlWordDefault = 0x37f; - -// Mask for the divide-by-zero exception. -constexpr uint16_t kX87ControlWordDiv0Mask = 1 << 2; - -// Default value for the SSE control register (MXCSR). See Intel SDM Vol 1, Ch -// 11.6.4 "Initialization of SSE/SSE3 Extensions". -constexpr uint32_t kMXCSRDefault = 0x1f80; - -// Mask for the divide-by-zero exception. -constexpr uint32_t kMXCSRDiv0Mask = 1 << 9; - -// Flag for a pending divide-by-zero exception. -constexpr uint32_t kMXCSRDiv0Flag = 1 << 2; - -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"); } - -void InIOHelper(int width, int value) { - EXPECT_EXIT( - { - switch (width) { - case 1: - asm volatile("inb %%dx, %%al" ::"d"(value) : "%eax"); - break; - case 2: - asm volatile("inw %%dx, %%ax" ::"d"(value) : "%eax"); - break; - case 4: - asm volatile("inl %%dx, %%eax" ::"d"(value) : "%eax"); - break; - default: - FAIL() << "invalid input width, only 1, 2 or 4 is allowed"; - } - }, - ::testing::KilledBySignal(SIGSEGV), ""); -} - -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), ""); -} - -// By default, x87 exceptions are masked and simply return a default value. -TEST(ExceptionTest, X87DivideByZeroMasked) { - int32_t quotient; - int32_t value = 1; - int32_t divisor = 0; - asm("fildl %[value]\r\n" - "fidivl %[divisor]\r\n" - "fistpl %[quotient]\r\n" - : [ quotient ] "=m"(quotient) - : [ value ] "m"(value), [ divisor ] "m"(divisor)); - - EXPECT_EQ(quotient, INT32_MIN); -} - -// When unmasked, division by zero raises SIGFPE. -TEST(ExceptionTest, X87DivideByZeroUnmasked) { - // See above. - struct sigaction sa = {}; - sa.sa_handler = SIG_DFL; - auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGFPE, sa)); - - EXPECT_EXIT( - { - // Clear the divide by zero exception mask. - constexpr uint16_t kControlWord = - kX87ControlWordDefault & ~kX87ControlWordDiv0Mask; - - int32_t quotient; - int32_t value = 1; - int32_t divisor = 0; - asm volatile( - "fldcw %[cw]\r\n" - "fildl %[value]\r\n" - "fidivl %[divisor]\r\n" - "fistpl %[quotient]\r\n" - : [ quotient ] "=m"(quotient) - : [ cw ] "m"(kControlWord), [ value ] "m"(value), - [ divisor ] "m"(divisor)); - }, - ::testing::KilledBySignal(SIGFPE), ""); -} - -// Pending exceptions in the x87 status register are not clobbered by syscalls. -TEST(ExceptionTest, X87StatusClobber) { - // See above. - struct sigaction sa = {}; - sa.sa_handler = SIG_DFL; - auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGFPE, sa)); - - EXPECT_EXIT( - { - // Clear the divide by zero exception mask. - constexpr uint16_t kControlWord = - kX87ControlWordDefault & ~kX87ControlWordDiv0Mask; - - int32_t quotient; - int32_t value = 1; - int32_t divisor = 0; - asm volatile( - "fildl %[value]\r\n" - "fidivl %[divisor]\r\n" - // Exception is masked, so it does not occur here. - "fistpl %[quotient]\r\n" - - // SYS_getpid placed in rax by constraint. - "syscall\r\n" - - // Unmask exception. The syscall didn't clobber the pending - // exception, so now it can be raised. - // - // N.B. "a floating-point exception will be generated upon execution - // of the *next* floating-point instruction". - "fldcw %[cw]\r\n" - "fwait\r\n" - : [ quotient ] "=m"(quotient) - : [ value ] "m"(value), [ divisor ] "m"(divisor), "a"(SYS_getpid), - [ cw ] "m"(kControlWord) - : "rcx", "r11"); - }, - ::testing::KilledBySignal(SIGFPE), ""); -} - -// By default, SSE exceptions are masked and simply return a default value. -TEST(ExceptionTest, SSEDivideByZeroMasked) { - uint32_t status; - int32_t quotient; - int32_t value = 1; - int32_t divisor = 0; - asm("cvtsi2ssl %[value], %%xmm0\r\n" - "cvtsi2ssl %[divisor], %%xmm1\r\n" - "divss %%xmm1, %%xmm0\r\n" - "cvtss2sil %%xmm0, %[quotient]\r\n" - : [ quotient ] "=r"(quotient), [ status ] "=r"(status) - : [ value ] "r"(value), [ divisor ] "r"(divisor) - : "xmm0", "xmm1"); - - EXPECT_EQ(quotient, INT32_MIN); -} - -// When unmasked, division by zero raises SIGFPE. -TEST(ExceptionTest, SSEDivideByZeroUnmasked) { - // See above. - struct sigaction sa = {}; - sa.sa_handler = SIG_DFL; - auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGFPE, sa)); - - EXPECT_EXIT( - { - // Clear the divide by zero exception mask. - constexpr uint32_t kMXCSR = kMXCSRDefault & ~kMXCSRDiv0Mask; - - int32_t quotient; - int32_t value = 1; - int32_t divisor = 0; - asm volatile( - "ldmxcsr %[mxcsr]\r\n" - "cvtsi2ssl %[value], %%xmm0\r\n" - "cvtsi2ssl %[divisor], %%xmm1\r\n" - "divss %%xmm1, %%xmm0\r\n" - "cvtss2sil %%xmm0, %[quotient]\r\n" - : [ quotient ] "=r"(quotient) - : [ mxcsr ] "m"(kMXCSR), [ value ] "r"(value), - [ divisor ] "r"(divisor) - : "xmm0", "xmm1"); - }, - ::testing::KilledBySignal(SIGFPE), ""); -} - -// Pending exceptions in the SSE status register are not clobbered by syscalls. -TEST(ExceptionTest, SSEStatusClobber) { - uint32_t mxcsr; - int32_t quotient; - int32_t value = 1; - int32_t divisor = 0; - asm("cvtsi2ssl %[value], %%xmm0\r\n" - "cvtsi2ssl %[divisor], %%xmm1\r\n" - "divss %%xmm1, %%xmm0\r\n" - // Exception is masked, so it does not occur here. - "cvtss2sil %%xmm0, %[quotient]\r\n" - - // SYS_getpid placed in rax by constraint. - "syscall\r\n" - - // Intel SDM Vol 1, Ch 10.2.3.1 "SIMD Floating-Point Mask and Flag Bits": - // "If LDMXCSR or FXRSTOR clears a mask bit and sets the corresponding - // exception flag bit, a SIMD floating-point exception will not be - // generated as a result of this change. The unmasked exception will be - // generated only upon the execution of the next SSE/SSE2/SSE3 instruction - // that detects the unmasked exception condition." - // - // Though ambiguous, empirical evidence indicates that this means that - // exception flags set in the status register will never cause an - // exception to be raised; only a new exception condition will do so. - // - // Thus here we just check for the flag itself rather than trying to raise - // the exception. - "stmxcsr %[mxcsr]\r\n" - : [ quotient ] "=r"(quotient), [ mxcsr ] "+m"(mxcsr) - : [ value ] "r"(value), [ divisor ] "r"(divisor), "a"(SYS_getpid) - : "xmm0", "xmm1", "rcx", "r11"); - - EXPECT_TRUE(mxcsr & kMXCSRDiv0Flag); -} - -TEST(ExceptionTest, IOAccessFault) { - // See above. - struct sigaction sa = {}; - sa.sa_handler = SIG_DFL; - auto const cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGSEGV, sa)); - - InIOHelper(1, 0x0); - InIOHelper(2, 0x7); - InIOHelper(4, 0x6); - InIOHelper(1, 0xffff); - InIOHelper(2, 0xffff); - InIOHelper(4, 0xfffd); -} - -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 |