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Diffstat (limited to 'test/syscalls/linux/fpsig_fork.cc')
-rw-r--r-- | test/syscalls/linux/fpsig_fork.cc | 105 |
1 files changed, 0 insertions, 105 deletions
diff --git a/test/syscalls/linux/fpsig_fork.cc b/test/syscalls/linux/fpsig_fork.cc deleted file mode 100644 index e7e9f06a1..000000000 --- a/test/syscalls/linux/fpsig_fork.cc +++ /dev/null @@ -1,105 +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. - -// This test verifies that fork(2) in a signal handler will correctly -// restore floating point state after the signal handler returns in both -// the child and parent. -#include <sys/time.h> - -#include "gtest/gtest.h" -#include "test/util/logging.h" -#include "test/util/test_util.h" -#include "test/util/thread_util.h" - -namespace gvisor { -namespace testing { - -namespace { - -#define GET_XMM(__var, __xmm) \ - asm volatile("movq %%" #__xmm ", %0" : "=r"(__var)) -#define SET_XMM(__var, __xmm) asm volatile("movq %0, %%" #__xmm : : "r"(__var)) - -int parent, child; - -void sigusr1(int s, siginfo_t* siginfo, void* _uc) { - // Fork and clobber %xmm0. The fpstate should be restored by sigreturn(2) - // in both parent and child. - child = fork(); - TEST_CHECK_MSG(child >= 0, "fork failed"); - - uint64_t val = SIGUSR1; - SET_XMM(val, xmm0); -} - -TEST(FPSigTest, Fork) { - parent = getpid(); - pid_t parent_tid = gettid(); - - struct sigaction sa = {}; - sigemptyset(&sa.sa_mask); - sa.sa_flags = SA_SIGINFO; - sa.sa_sigaction = sigusr1; - ASSERT_THAT(sigaction(SIGUSR1, &sa, nullptr), SyscallSucceeds()); - - // The amd64 ABI specifies that the XMM register set is caller-saved. This - // implies that if there is any function call between SET_XMM and GET_XMM the - // compiler might save/restore xmm0 implicitly. This defeats the entire - // purpose of the test which is to verify that fpstate is restored by - // sigreturn(2). - // - // This is the reason why 'tgkill(getpid(), gettid(), SIGUSR1)' is implemented - // in inline assembly below. - // - // If the OS is broken and registers are clobbered by the child, using tgkill - // to signal the current thread increases the likelihood that this thread will - // be the one clobbered. - - uint64_t expected = 0xdeadbeeffacefeed; - SET_XMM(expected, xmm0); - - asm volatile( - "movl %[killnr], %%eax;" - "movl %[parent], %%edi;" - "movl %[tid], %%esi;" - "movl %[sig], %%edx;" - "syscall;" - : - : [killnr] "i"(__NR_tgkill), [parent] "rm"(parent), - [tid] "rm"(parent_tid), [sig] "i"(SIGUSR1) - : "rax", "rdi", "rsi", "rdx", - // Clobbered by syscall. - "rcx", "r11"); - - uint64_t got; - GET_XMM(got, xmm0); - - if (getpid() == parent) { // Parent. - int status; - ASSERT_THAT(waitpid(child, &status, 0), SyscallSucceedsWithValue(child)); - EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0); - } - - // TEST_CHECK_MSG since this may run in the child. - TEST_CHECK_MSG(expected == got, "Bad xmm0 value"); - - if (getpid() != parent) { // Child. - _exit(0); - } -} - -} // namespace - -} // namespace testing -} // namespace gvisor |