ipc: Make sys_semtimedop() y2038 safe

struct timespec is not y2038 safe on 32 bit machines.
Replace timespec with y2038 safe struct timespec64.

Note that the patch only changes the internals without
modifying the syscall interface. This will be part
of a separate series.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

ipc/sem.c

@@ -1856,7 +1856,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
 }
 
 static long do_semtimedop(int semid, struct sembuf __user *tsops,
-		unsigned nsops, const struct timespec *timeout)
+		unsigned nsops, const struct timespec64 *timeout)
 {
 	int error = -EINVAL;
 	struct sem_array *sma;
@@ -1892,7 +1892,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
 			error = -EINVAL;
 			goto out_free;
 		}
-		jiffies_left = timespec_to_jiffies(timeout);
+		jiffies_left = timespec64_to_jiffies(timeout);
 	}
 
 	max = 0;
@@ -2111,8 +2111,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 		unsigned, nsops, const struct timespec __user *, timeout)
 {
 	if (timeout) {
-		struct timespec ts;
-		if (copy_from_user(&ts, timeout, sizeof(*timeout)))
+		struct timespec64 ts;
+		if (get_timespec64(&ts, timeout))
 			return -EFAULT;
 		return do_semtimedop(semid, tsops, nsops, &ts);
 	}
@@ -2125,8 +2125,8 @@ COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,
 		       const struct compat_timespec __user *, timeout)
 {
 	if (timeout) {
-		struct timespec ts;
-		if (compat_get_timespec(&ts, timeout))
+		struct timespec64 ts;
+		if (compat_get_timespec64(&ts, timeout))
 			return -EFAULT;
 		return do_semtimedop(semid, tsems, nsops, &ts);
 	}