2 files changed, 39 insertions, 5 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 0036164bb0fb..3e64814e888e 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -287,10 +287,18 @@ int start_userspace(unsigned long stub_stack)
 
 void userspace(struct uml_pt_regs *regs)
 {
+        struct itimerval timer;
+        unsigned long long nsecs, now;
         int err, status, op, pid = userspace_pid[0];
         /* To prevent races if using_sysemu changes under us.*/
         int local_using_sysemu;
 
+        if (getitimer(ITIMER_VIRTUAL, &timer))
+                printk("Failed to get itimer, errno = %d\n", errno);
+        nsecs = timer.it_value.tv_sec * BILLION +
+                timer.it_value.tv_usec * 1000;
+        nsecs += os_nsecs();
+
         while (1) {
                 restore_registers(pid, regs);
 
@@ -333,8 +341,18 @@ void userspace(struct uml_pt_regs *regs)
                         case SIGTRAP:
                                 relay_signal(SIGTRAP, regs);
                                 break;
-                        case SIGIO:
                         case SIGVTALRM:
+                                now = os_nsecs();
+                                if(now < nsecs)
+                                        break;
+                                block_signals();
+                                (*sig_info[sig])(sig, regs);
+                                unblock_signals();
+                                nsecs = timer.it_value.tv_sec * BILLION +
+                                        timer.it_value.tv_usec * 1000;
+                                nsecs += os_nsecs();
+                                break;
+                        case SIGIO:
                         case SIGILL:
                         case SIGBUS:
                         case SIGFPE:
@@ -378,6 +396,7 @@ __initcall(init_thread_regs);
 
 int copy_context_skas0(unsigned long new_stack, int pid)
 {
+        struct timeval tv = { .tv_sec = 0, .tv_usec = 1000000 / UM_HZ };
         int err;
         unsigned long current_stack = current_stub_stack();
         struct stub_data *data = (struct stub_data *) current_stack;
@@ -392,9 +411,9 @@ int copy_context_skas0(unsigned long new_stack, int pid)
         *data = ((struct stub_data) { .offset   = MMAP_OFFSET(new_offset),
                                       .fd       = new_fd,
                                       .timer    = ((struct itimerval)
-                                                    { { 0, 1000000 / UM_HZ },
-                                                      { 0, 1000000 / UM_HZ }})
-                                 });
+                                                   { .it_value = tv,
+                                                     .it_interval = tv }) });
+
         err = ptrace_setregs(pid, thread_regs);
         if (err < 0)
                 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index 6ff3d98281ba..9ffc61ac8ed6 100644
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -26,6 +26,21 @@ int set_interval(void)
         return 0;
 }
 
+int timer_one_shot(int ticks)
+{
+        unsigned long usec = ticks * 1000000 / UM_HZ;
+        unsigned long sec = usec / 1000000;
+        struct itimerval interval;
+
+        usec %= 1000000;
+        interval = ((struct itimerval) { { 0, 0 }, { sec, usec } });
+
+        if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
+                return -errno;
+
+        return 0;
+}
+
 void disable_timer(void)
 {
         struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
@@ -74,7 +89,7 @@ unsigned long long os_nsecs(void)
         struct timeval tv;
 
         gettimeofday(&tv, NULL);
-        return (unsigned long long) tv.tv_sec * BILLION + tv.tv_usec * 1000;
+        return timeval_to_ns(&tv);
 }
 
 void idle_sleep(int secs)