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[50.150.100.179]) by smtp.gmail.com with ESMTPSA id m20sm7792029pgd.32.2017.03.20.01.17.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 20 Mar 2017 01:17:15 -0700 (PDT) From: Kyle Huey X-Google-Original-From: Kyle Huey To: Robert O'Callahan , Thomas Gleixner , Andy Lutomirski , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Jeff Dike , Richard Weinberger , Alexander Viro , Shuah Khan , Dave Hansen , Borislav Petkov , Peter Zijlstra , Boris Ostrovsky , Len Brown , "Rafael J. Wysocki" , Dmitry Safonov , David Matlack , Nadav Amit , Andi Kleen , Grzegorz Andrejczuk Cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH v16 09/10] x86/arch_prctl: Selftest for ARCH_[GET|SET]_CPUID Date: Mon, 20 Mar 2017 01:16:27 -0700 Message-Id: <20170320081628.18952-10-khuey@kylehuey.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170320081628.18952-1-khuey@kylehuey.com> References: <20170320081628.18952-1-khuey@kylehuey.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Test disabling and reenabling the cpuid instruction via the new arch_prctl ARCH_SET_CPUID, retrieving the current state via ARCH_GET_CPUID, and the expected behaviors across fork() and exec(). Signed-off-by: Kyle Huey --- tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/cpuid_fault.c | 251 ++++++++++++++++++++++++++++++ 2 files changed, 252 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/cpuid_fault.c diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 38e0a9ca5d71..acda4e5fcf25 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -6,7 +6,7 @@ include ../lib.mk TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall test_mremap_vdso \ check_initial_reg_state sigreturn ldt_gdt iopl mpx-mini-test ioperm \ - protection_keys test_vdso + protection_keys test_vdso cpuid_fault TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer diff --git a/tools/testing/selftests/x86/cpuid_fault.c b/tools/testing/selftests/x86/cpuid_fault.c new file mode 100644 index 000000000000..e3b93c28c655 --- /dev/null +++ b/tools/testing/selftests/x86/cpuid_fault.c @@ -0,0 +1,251 @@ + +/* + * Tests for arch_prctl(ARCH_GET_CPUID, ...) / arch_prctl(ARCH_SET_CPUID, ...) + * + * Basic test to test behaviour of ARCH_GET_CPUID and ARCH_SET_CPUID + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +/* +#define ARCH_GET_CPUID 0x1005 +#define ARCH_SET_CPUID 0x1006 +#ifdef __x86_64__ +#define SYS_arch_prctl 158 +#else +#define SYS_arch_prctl 384 +#endif +*/ + +const char *cpuid_names[] = { + [0] = "[cpuid disabled]", + [1] = "[cpuid enabled]", +}; + +int arch_prctl(int option, unsigned long arg2) +{ + return syscall(SYS_arch_prctl, option, arg2); +} + +int cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx, + unsigned int *edx) +{ + return __get_cpuid(0, eax, ebx, ecx, edx); +} + +int do_child_exec_test(int eax, int ebx, int ecx, int edx) +{ + int cpuid_val = 0, child = 0, status = 0; + + printf("arch_prctl(ARCH_GET_CPUID); "); + + cpuid_val = arch_prctl(ARCH_GET_CPUID, 0); + if (cpuid_val < 0) + errx(1, "ARCH_GET_CPUID fails now, but not before?"); + + printf("cpuid_val == %s\n", cpuid_names[cpuid_val]); + if (cpuid_val != 0) + errx(1, "How did cpuid get re-enabled on fork?"); + + child = fork(); + if (child == 0) { + cpuid_val = arch_prctl(ARCH_GET_CPUID, 0); + if (cpuid_val < 0) + errx(1, "ARCH_GET_CPUID fails now, but not before?"); + + printf("cpuid_val == %s\n", cpuid_names[cpuid_val]); + if (cpuid_val != 0) + errx(1, "How did cpuid get re-enabled on fork?"); + + printf("exec\n"); + execl("/proc/self/exe", "cpuid-fault", "-early-return", NULL); + } + + if (child != waitpid(child, &status, 0)) + errx(1, "waitpid failed!?"); + + if (WEXITSTATUS(status) != 0) + errx(1, "Execed child exited abnormally"); + + return 0; +} + +int child_received_signal; + +void child_sigsegv_cb(int sig) +{ + int cpuid_val = 0; + + child_received_signal = 1; + printf("[ SIG_SEGV ]\n"); + printf("arch_prctl(ARCH_GET_CPUID); "); + + cpuid_val = arch_prctl(ARCH_GET_CPUID, 0); + if (cpuid_val < 0) + errx(1, "ARCH_GET_CPUID fails now, but not before?"); + + printf("cpuid_val == %s\n", cpuid_names[cpuid_val]); + printf("arch_prctl(ARCH_SET_CPUID, 1)\n"); + if (arch_prctl(ARCH_SET_CPUID, 1) != 0) + exit(errno); + + printf("cpuid() == "); +} + +int do_child_test(void) +{ + unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0; + + signal(SIGSEGV, child_sigsegv_cb); + + /* the child starts out with cpuid disabled, the signal handler + * attempts to enable and retry + */ + printf("cpuid() == "); + cpuid(&eax, &ebx, &ecx, &edx); + printf("{%x, %x, %x, %x}\n", eax, ebx, ecx, edx); + return child_received_signal ? 0 : 42; +} + +int signal_count; + +void sigsegv_cb(int sig) +{ + int cpuid_val = 0; + + signal_count++; + printf("[ SIG_SEGV ]\n"); + printf("arch_prctl(ARCH_GET_CPUID); "); + + cpuid_val = arch_prctl(ARCH_GET_CPUID, 0); + if (cpuid_val < 0) + errx(1, "ARCH_GET_CPUID fails now, but not before?"); + + printf("cpuid_val == %s\n", cpuid_names[cpuid_val]); + printf("arch_prctl(ARC_SET_CPUID, 1)\n"); + if (arch_prctl(ARCH_SET_CPUID, 1) != 0) + errx(1, "ARCH_SET_CPUID failed!"); + + printf("cpuid() == "); +} + +int main(int argc, char **argv) +{ + int cpuid_val = 0, child = 0, status = 0; + unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0; + + signal(SIGSEGV, sigsegv_cb); + setvbuf(stdout, NULL, _IONBF, 0); + + cpuid(&eax, &ebx, &ecx, &edx); + printf("cpuid() == {%x, %x, %x, %x}\n", eax, ebx, ecx, edx); + printf("arch_prctl(ARCH_GET_CPUID); "); + + cpuid_val = arch_prctl(ARCH_GET_CPUID, 0); + if (cpuid_val < 0) { + if (errno == EINVAL) { + printf("ARCH_GET_CPUID is unsupported on this kernel.\n"); + fflush(stdout); + exit(0); /* no ARCH_GET_CPUID on this system */ + } else if (errno == ENODEV) { + printf("ARCH_GET_CPUID is unsupported on this hardware.\n"); + fflush(stdout); + exit(0); /* no ARCH_GET_CPUID on this system */ + } else { + errx(errno, "ARCH_GET_CPUID failed unexpectedly!"); + } + } + + printf("cpuid_val == %s\n", cpuid_names[cpuid_val]); + cpuid(&eax, &ebx, &ecx, &edx); + printf("cpuid() == {%x, %x, %x, %x}\n", eax, ebx, ecx, edx); + printf("arch_prctl(ARCH_SET_CPUID, 1)\n"); + + if (arch_prctl(ARCH_SET_CPUID, 1) != 0) { + if (errno == EINVAL) { + printf("ARCH_SET_CPUID is unsupported on this kernel."); + exit(0); /* no ARCH_SET_CPUID on this system */ + } else if (errno == ENODEV) { + printf("ARCH_SET_CPUID is unsupported on this hardware."); + exit(0); /* no ARCH_SET_CPUID on this system */ + } else { + errx(errno, "ARCH_SET_CPUID failed unexpectedly!"); + } + } + + + cpuid(&eax, &ebx, &ecx, &edx); + printf("cpuid() == {%x, %x, %x, %x}\n", eax, ebx, ecx, edx); + printf("arch_prctl(ARCH_SET_CPUID, 0)\n"); + fflush(stdout); + + if (arch_prctl(ARCH_SET_CPUID, 0) == -1) + errx(1, "ARCH_SET_CPUID failed!"); + + printf("cpuid() == "); + eax = ebx = ecx = edx = 0; + cpuid(&eax, &ebx, &ecx, &edx); + printf("{%x, %x, %x, %x}\n", eax, ebx, ecx, edx); + printf("arch_prctl(ARCH_SET_CPUID, 0)\n"); + + if (signal_count != 1) + errx(1, "cpuid didn't fault!"); + + if (arch_prctl(ARCH_SET_CPUID, 0) == -1) + errx(1, "ARCH_SET_CPUID failed!"); + + if (argc > 1) + exit(0); /* Don't run the whole test again if we were execed */ + + printf("do_child_test\n"); + child = fork(); + if (child == 0) + return do_child_test(); + + if (child != waitpid(child, &status, 0)) + errx(1, "waitpid failed!?"); + + if (WEXITSTATUS(status) != 0) + errx(1, "Child exited abnormally!"); + + /* The child enabling cpuid should not have affected us */ + printf("cpuid() == "); + eax = ebx = ecx = edx = 0; + cpuid(&eax, &ebx, &ecx, &edx); + printf("{%x, %x, %x, %x}\n", eax, ebx, ecx, edx); + printf("arch_prctl(ARCH_SET_CPUID, 0)\n"); + + if (signal_count != 2) + errx(1, "cpuid didn't fault!"); + + if (arch_prctl(ARCH_SET_CPUID, 0) == -1) + errx(1, "ARCH_SET_CPUID failed!"); + + /* Our ARCH_CPUID_SIGSEGV should not propagate through exec */ + printf("do_child_exec_test\n"); + fflush(stdout); + + child = fork(); + if (child == 0) + return do_child_exec_test(eax, ebx, ecx, edx); + + if (child != waitpid(child, &status, 0)) + errx(1, "waitpid failed!?"); + + if (WEXITSTATUS(status) != 0) + errx(1, "Child exited abnormally!"); + + printf("All tests passed!\n"); + exit(EXIT_SUCCESS); +}