posix-timers: Move compat versions of clock_gettime/settime/getres

Move them to the native implementations and get rid of the set_fs() hackery.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170607084241.28657-13-viro@ZenIV.linux.org.uk

kernel/compat.c

@@ -598,57 +598,6 @@ COMPAT_SYSCALL_DEFINE3(timer_create, clockid_t, which_clock,
 	return sys_timer_create(which_clock, event, created_timer_id);
 }
 
-COMPAT_SYSCALL_DEFINE2(clock_settime, clockid_t, which_clock,
-		       struct compat_timespec __user *, tp)
-{
-	long err;
-	mm_segment_t oldfs;
-	struct timespec ts;
-
-	if (compat_get_timespec(&ts, tp))
-		return -EFAULT;
-	oldfs = get_fs();
-	set_fs(KERNEL_DS);
-	err = sys_clock_settime(which_clock,
-				(struct timespec __user *) &ts);
-	set_fs(oldfs);
-	return err;
-}
-
-COMPAT_SYSCALL_DEFINE2(clock_gettime, clockid_t, which_clock,
-		       struct compat_timespec __user *, tp)
-{
-	long err;
-	mm_segment_t oldfs;
-	struct timespec ts;
-
-	oldfs = get_fs();
-	set_fs(KERNEL_DS);
-	err = sys_clock_gettime(which_clock,
-				(struct timespec __user *) &ts);
-	set_fs(oldfs);
-	if (!err && compat_put_timespec(&ts, tp))
-		return -EFAULT;
-	return err;
-}
-
-COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
-		       struct compat_timespec __user *, tp)
-{
-	long err;
-	mm_segment_t oldfs;
-	struct timespec ts;
-
-	oldfs = get_fs();
-	set_fs(KERNEL_DS);
-	err = sys_clock_getres(which_clock,
-			       (struct timespec __user *) &ts);
-	set_fs(oldfs);
-	if (!err && tp && compat_put_timespec(&ts, tp))
-		return -EFAULT;
-	return err;
-}
-
 /*
  * We currently only need the following fields from the sigevent
  * structure: sigev_value, sigev_signo, sig_notify and (sometimes

kernel/time/posix-stubs.c

@@ -137,6 +137,59 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 }
 
 #ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
+		       struct compat_timespec __user *, tp)
+{
+	struct timespec64 new_tp64;
+	struct timespec new_tp;
+
+	if (which_clock != CLOCK_REALTIME)
+		return -EINVAL;
+	if (compat_get_timespec(&new_tp, tp))
+		return -EFAULT;
+
+	new_tp64 = timespec_to_timespec64(new_tp);
+	return do_sys_settimeofday64(&new_tp64, NULL);
+}
+
+COMPAT_SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
+		       struct compat_timespec __user *,tp)
+{
+	struct timespec64 kernel_tp64;
+	struct timespec kernel_tp;
+
+	switch (which_clock) {
+	case CLOCK_REALTIME: ktime_get_real_ts64(&kernel_tp64); break;
+	case CLOCK_MONOTONIC: ktime_get_ts64(&kernel_tp64); break;
+	case CLOCK_BOOTTIME: get_monotonic_boottime64(&kernel_tp64); break;
+	default: return -EINVAL;
+	}
+
+	kernel_tp = timespec64_to_timespec(kernel_tp64);
+	if (compat_put_timespec(&kernel_tp, tp))
+		return -EFAULT;
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
+		       struct compat_timespec __user *, tp)
+{
+	struct timespec rtn_tp = {
+		.tv_sec = 0,
+		.tv_nsec = hrtimer_resolution,
+	};
+
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+	case CLOCK_MONOTONIC:
+	case CLOCK_BOOTTIME:
+		if (compat_put_timespec(&rtn_tp, tp))
+			return -EFAULT;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
 COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
 		       struct compat_timespec __user *, rqtp,
 		       struct compat_timespec __user *, rmtp)

kernel/time/posix-timers.c

@@ -1082,8 +1082,66 @@ SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
 	return err;
 }
 
+SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
+		struct timespec __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 rtn_tp64;
+	struct timespec rtn_tp;
+	int error;
+
+	if (!kc)
+		return -EINVAL;
+
+	error = kc->clock_getres(which_clock, &rtn_tp64);
+	rtn_tp = timespec64_to_timespec(rtn_tp64);
+
+	if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp)))
+		error = -EFAULT;
+
+	return error;
+}
+
 #ifdef CONFIG_COMPAT
 
+COMPAT_SYSCALL_DEFINE2(clock_settime, clockid_t, which_clock,
+		       struct compat_timespec __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 new_tp64;
+	struct timespec new_tp;
+
+	if (!kc || !kc->clock_set)
+		return -EINVAL;
+
+	if (compat_get_timespec(&new_tp, tp))
+		return -EFAULT;
+
+	new_tp64 = timespec_to_timespec64(new_tp);
+
+	return kc->clock_set(which_clock, &new_tp64);
+}
+
+COMPAT_SYSCALL_DEFINE2(clock_gettime, clockid_t, which_clock,
+		       struct compat_timespec __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 kernel_tp64;
+	struct timespec kernel_tp;
+	int error;
+
+	if (!kc)
+		return -EINVAL;
+
+	error = kc->clock_get(which_clock, &kernel_tp64);
+	kernel_tp = timespec64_to_timespec(kernel_tp64);
+
+	if (!error && compat_put_timespec(&kernel_tp, tp))
+		error = -EFAULT;
+
+	return error;
+}
+
 COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
 		       struct compat_timex __user *, utp)
 {
@@ -1107,10 +1165,9 @@ COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
 
 	return err;
 }
-#endif
 
-SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
-		struct timespec __user *, tp)
+COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
+		       struct compat_timespec __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 rtn_tp64;
@@ -1123,11 +1180,12 @@ SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
 	error = kc->clock_getres(which_clock, &rtn_tp64);
 	rtn_tp = timespec64_to_timespec(rtn_tp64);
 
-	if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp)))
+	if (!error && tp && compat_put_timespec(&rtn_tp, tp))
 		error = -EFAULT;
 
 	return error;
 }
+#endif
 
 /*
  * nanosleep for monotonic and realtime clocks