1 files changed, 107 insertions, 5 deletions

diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
index 4e25d38c8bbd..bc0ecc2e862e 100644
--- a/tools/testing/selftests/x86/syscall_arg_fault.c
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -15,9 +15,30 @@
 #include <setjmp.h>
 #include <errno.h>
 
+#ifdef __x86_64__
+# define WIDTH "q"
+#else
+# define WIDTH "l"
+#endif
+
 /* Our sigaltstack scratch space. */
 static unsigned char altstack_data[SIGSTKSZ];
 
+static unsigned long get_eflags(void)
+{
+        unsigned long eflags;
+        asm volatile ("pushf" WIDTH "\n\tpop" WIDTH " %0" : "=rm" (eflags));
+        return eflags;
+}
+
+static void set_eflags(unsigned long eflags)
+{
+        asm volatile ("push" WIDTH " %0\n\tpopf" WIDTH
+                      : : "rm" (eflags) : "flags");
+}
+
+#define X86_EFLAGS_TF (1UL << 8)
+
 static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
                        int flags)
 {
@@ -35,13 +56,22 @@ static sigjmp_buf jmpbuf;
 
 static volatile sig_atomic_t n_errs;
 
+#ifdef __x86_64__
+#define REG_AX REG_RAX
+#define REG_IP REG_RIP
+#else
+#define REG_AX REG_EAX
+#define REG_IP REG_EIP
+#endif
+
 static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
 {
         ucontext_t *ctx = (ucontext_t*)ctx_void;
+        long ax = (long)ctx->uc_mcontext.gregs[REG_AX];
 
-        if (ctx->uc_mcontext.gregs[REG_EAX] != -EFAULT) {
-                printf("[FAIL]\tAX had the wrong value: 0x%x\n",
-                       ctx->uc_mcontext.gregs[REG_EAX]);
+        if (ax != -EFAULT && ax != -ENOSYS) {
+                printf("[FAIL]\tAX had the wrong value: 0x%lx\n",
+                       (unsigned long)ax);
                 n_errs++;
         } else {
                 printf("[OK]\tSeems okay\n");
@@ -50,9 +80,42 @@ static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
         siglongjmp(jmpbuf, 1);
 }
 
+static volatile sig_atomic_t sigtrap_consecutive_syscalls;
+
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+        /*
+         * KVM has some bugs that can cause us to stop making progress.
+         * detect them and complain, but don't infinite loop or fail the
+         * test.
+         */
+
+        ucontext_t *ctx = (ucontext_t*)ctx_void;
+        unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP];
+
+        if (*ip == 0x340f || *ip == 0x050f) {
+                /* The trap was on SYSCALL or SYSENTER */
+                sigtrap_consecutive_syscalls++;
+                if (sigtrap_consecutive_syscalls > 3) {
+                        printf("[WARN]\tGot stuck single-stepping -- you probably have a KVM bug\n");
+                        siglongjmp(jmpbuf, 1);
+                }
+        } else {
+                sigtrap_consecutive_syscalls = 0;
+        }
+}
+
 static void sigill(int sig, siginfo_t *info, void *ctx_void)
 {
-        printf("[SKIP]\tIllegal instruction\n");
+        ucontext_t *ctx = (ucontext_t*)ctx_void;
+        unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP];
+
+        if (*ip == 0x0b0f) {
+                /* one of the ud2 instructions faulted */
+                printf("[OK]\tSYSCALL returned normally\n");
+        } else {
+                printf("[SKIP]\tIllegal instruction\n");
+        }
         siglongjmp(jmpbuf, 1);
 }
 
@@ -120,9 +183,48 @@ int main()
                         "movl $-1, %%ebp\n\t"
                         "movl $-1, %%esp\n\t"
                         "syscall\n\t"
-                        "pushl $0"      /* make sure we segfault cleanly */
+                        "ud2"           /* make sure we recover cleanly */
+                        : : : "memory", "flags");
+        }
+
+        printf("[RUN]\tSYSENTER with TF and invalid state\n");
+        sethandler(SIGTRAP, sigtrap, SA_ONSTACK);
+
+        if (sigsetjmp(jmpbuf, 1) == 0) {
+                sigtrap_consecutive_syscalls = 0;
+                set_eflags(get_eflags() | X86_EFLAGS_TF);
+                asm volatile (
+                        "movl $-1, %%eax\n\t"
+                        "movl $-1, %%ebx\n\t"
+                        "movl $-1, %%ecx\n\t"
+                        "movl $-1, %%edx\n\t"
+                        "movl $-1, %%esi\n\t"
+                        "movl $-1, %%edi\n\t"
+                        "movl $-1, %%ebp\n\t"
+                        "movl $-1, %%esp\n\t"
+                        "sysenter"
+                        : : : "memory", "flags");
+        }
+        set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+
+        printf("[RUN]\tSYSCALL with TF and invalid state\n");
+        if (sigsetjmp(jmpbuf, 1) == 0) {
+                sigtrap_consecutive_syscalls = 0;
+                set_eflags(get_eflags() | X86_EFLAGS_TF);
+                asm volatile (
+                        "movl $-1, %%eax\n\t"
+                        "movl $-1, %%ebx\n\t"
+                        "movl $-1, %%ecx\n\t"
+                        "movl $-1, %%edx\n\t"
+                        "movl $-1, %%esi\n\t"
+                        "movl $-1, %%edi\n\t"
+                        "movl $-1, %%ebp\n\t"
+                        "movl $-1, %%esp\n\t"
+                        "syscall\n\t"
+                        "ud2"           /* make sure we recover cleanly */
                         : : : "memory", "flags");
         }
+        set_eflags(get_eflags() & ~X86_EFLAGS_TF);
 
         return 0;
 }