y2038: signal: Change rt_sigtimedwait to use __kernel_timespec

This changes sys_rt_sigtimedwait() to use get_timespec64(), changing
the timeout type to __kernel_timespec, which will be changed to use
a 64-bit time_t in the future. Since the do_sigtimedwait() core
function changes, we also have to modify the compat version of this
system call in the same way.

Signed-off-by: Arnd Bergmann <[e-mail]>

include/linux/syscalls.h

···
 asmlinkage long sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize);
 asmlinkage long sys_rt_sigtimedwait(const sigset_t __user *uthese,
 				siginfo_t __user *uinfo,
-				const struct timespec __user *uts,
+				const struct __kernel_timespec __user *uts,
 				size_t sigsetsize);
 asmlinkage long sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo);
 

kernel/signal.c

···
  *  @ts: upper bound on process time suspension
  */
 static int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
-		    const struct timespec *ts)
+		    const struct timespec64 *ts)
 {
 	ktime_t *to = NULL, timeout = KTIME_MAX;
 	struct task_struct *tsk = current;
···
 	int sig, ret = 0;
 
 	if (ts) {
-		if (!timespec_valid(ts))
+		if (!timespec64_valid(ts))
 			return -EINVAL;
-		timeout = timespec_to_ktime(*ts);
+		timeout = timespec64_to_ktime(*ts);
 		to = &timeout;
 	}
 
···
  *  @sigsetsize: size of sigset_t type
  */
 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
-		siginfo_t __user *, uinfo, const struct timespec __user *, uts,
+		siginfo_t __user *, uinfo,
+		const struct __kernel_timespec __user *, uts,
 		size_t, sigsetsize)
 {
 	sigset_t these;
-	struct timespec ts;
+	struct timespec64 ts;
 	siginfo_t info;
 	int ret;
 
···
 		return -EFAULT;
 
 	if (uts) {
-		if (copy_from_user(&ts, uts, sizeof(ts)))
+		if (get_timespec64(&ts, uts))
 			return -EFAULT;
 	}
 
···
 		struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
 {
 	sigset_t s;
-	struct timespec t;
+	struct timespec64 t;
 	siginfo_t info;
 	long ret;
 
···
 		return -EFAULT;
 
 	if (uts) {
-		if (compat_get_timespec(&t, uts))
+		if (get_old_timespec32(&t, uts))
 			return -EFAULT;
 	}