selftests/x86: Add test_vdso to test getcpu()

I'll eventually add tests for more vDSO functions here.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Megha <megha.dey@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/945cd29901a62a3cc6ea7d6ee5e389ab1ec1ac0c.1479320367.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 124 insertions, 1 deletions

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index a89f80a5b711..8c1cb423cfe6 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 \
-                        protection_keys
+                        protection_keys test_vdso
 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/test_vdso.c b/tools/testing/selftests/x86/test_vdso.c
new file mode 100644
index 000000000000..65d7a2bf7e14
--- /dev/null
+++ b/tools/testing/selftests/x86/test_vdso.c
@@ -0,0 +1,123 @@
+/*
+ * ldt_gdt.c - Test cases for LDT and GDT access
+ * Copyright (c) 2011-2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <sys/time.h>
+#include <time.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <dlfcn.h>
+#include <string.h>
+#include <errno.h>
+#include <sched.h>
+#include <stdbool.h>
+
+#ifndef SYS_getcpu
+# ifdef __x86_64__
+#  define SYS_getcpu 309
+# else
+#  define SYS_getcpu 318
+# endif
+#endif
+
+int nerrs = 0;
+
+#ifdef __x86_64__
+# define VSYS(x) (x)
+#else
+# define VSYS(x) 0
+#endif
+
+typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
+
+const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);
+getcpu_t vdso_getcpu;
+
+void fill_function_pointers()
+{
+        void *vdso = dlopen("linux-vdso.so.1",
+                            RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+        if (!vdso)
+                vdso = dlopen("linux-gate.so.1",
+                              RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+        if (!vdso) {
+                printf("[WARN]\tfailed to find vDSO\n");
+                return;
+        }
+
+        vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");
+        if (!vdso_getcpu)
+                printf("Warning: failed to find getcpu in vDSO\n");
+}
+
+static long sys_getcpu(unsigned * cpu, unsigned * node,
+                       void* cache)
+{
+        return syscall(__NR_getcpu, cpu, node, cache);
+}
+
+static void test_getcpu(void)
+{
+        printf("[RUN]\tTesting getcpu...\n");
+
+        for (int cpu = 0; ; cpu++) {
+                cpu_set_t cpuset;
+                CPU_ZERO(&cpuset);
+                CPU_SET(cpu, &cpuset);
+                if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+                        return;
+
+                unsigned cpu_sys, cpu_vdso, cpu_vsys,
+                        node_sys, node_vdso, node_vsys;
+                long ret_sys, ret_vdso = 1, ret_vsys = 1;
+                unsigned node;
+
+                ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
+                if (vdso_getcpu)
+                        ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
+                if (vgetcpu)
+                        ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
+
+                if (!ret_sys)
+                        node = node_sys;
+                else if (!ret_vdso)
+                        node = node_vdso;
+                else if (!ret_vsys)
+                        node = node_vsys;
+
+                bool ok = true;
+                if (!ret_sys && (cpu_sys != cpu || node_sys != node))
+                        ok = false;
+                if (!ret_vdso && (cpu_vdso != cpu || node_vdso != node))
+                        ok = false;
+                if (!ret_vsys && (cpu_vsys != cpu || node_vsys != node))
+                        ok = false;
+
+                printf("[%s]\tCPU %u:", ok ? "OK" : "FAIL", cpu);
+                if (!ret_sys)
+                        printf(" syscall: cpu %u, node %u", cpu_sys, node_sys);
+                if (!ret_vdso)
+                        printf(" vdso: cpu %u, node %u", cpu_vdso, node_vdso);
+                if (!ret_vsys)
+                        printf(" vsyscall: cpu %u, node %u", cpu_vsys,
+                               node_vsys);
+                printf("\n");
+
+                if (!ok)
+                        nerrs++;
+        }
+}
+
+int main(int argc, char **argv)
+{
+        fill_function_pointers();
+
+        test_getcpu();
+
+        return nerrs ? 1 : 0;
+}