commit edbeda46322fbcb15af2d2d0f2daffb0cd349a5a
author Al Viro <viro@zeniv.linux.org.uk> Wed Jun 07 09:42:31 2017 +0100
committer Thomas Gleixner <tglx@linutronix.de> Wed Jun 14 00:00:42 2017 +0200
tree a4aa5436d4e5dcce6f4d041d13c521e1660331b7
parent 99e6c0e6ec349575886ca7daffc9cb7ec583176f

time/posix-timers: Move the compat copyouts to the nanosleep implementations

Turn restart_block.nanosleep.{rmtp,compat_rmtp} into a tagged union (kind =
1 -> native, kind = 2 -> compat, kind = 0 -> nothing) and make the places
doing actual copyout handle compat as well as native (that will become a
helper in the next commit).  Result: compat wrappers, messing with
reassignments, etc. are gone.

[ tglx: Folded in a variant of Peter Zijlstras enum patch ]

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/20170607084241.28657-6-viro@ZenIV.linux.org.uk

kernel/time/hrtimer.c

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index baa7b84..5370da8 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -51,6 +51,7 @@
 #include <linux/sched/debug.h>
 #include <linux/timer.h>
 #include <linux/freezer.h>
+#include <linux/compat.h>
 
 #include <linux/uaccess.h>
 
@@ -1441,7 +1442,8 @@ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
 
 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
 {
-	struct timespec __user *rmtp;
+	struct restart_block *restart;
+
 	hrtimer_init_sleeper(t, current);
 
 	do {
@@ -1461,15 +1463,23 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
 	if (!t->task)
 		return 0;
 
-	rmtp = current->restart_block.nanosleep.rmtp;
-	if (rmtp) {
-		struct timespec rmt;
+	restart = &current->restart_block;
+	if (restart->nanosleep.type != TT_NONE) {
 		ktime_t rem = hrtimer_expires_remaining(&t->timer);
+		struct timespec rmt;
+
 		if (rem <= 0)
 			return 0;
 		rmt = ktime_to_timespec(rem);
 
-		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+#ifdef CONFIG_COMPAT
+		if (restart->nanosleep.type == TT_COMPAT) {
+			if (compat_put_timespec(&rmt,
+						restart->nanosleep.compat_rmtp))
+				return -EFAULT;
+		} else
+#endif
+		if (copy_to_user(restart->nanosleep.rmtp, &rmt, sizeof(rmt)))
 			return -EFAULT;
 	}
 	return -ERESTART_RESTARTBLOCK;
@@ -1535,10 +1545,32 @@ SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
 	if (!timespec64_valid(&tu64))
 		return -EINVAL;
 
+	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
 	current->restart_block.nanosleep.rmtp = rmtp;
 	return hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 }
 
+#ifdef CONFIG_COMPAT
+
+COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp,
+		       struct compat_timespec __user *, rmtp)
+{
+	struct timespec64 tu64;
+	struct timespec tu;
+
+	if (compat_get_timespec(&tu, rqtp))
+		return -EFAULT;
+
+	tu64 = timespec_to_timespec64(tu);
+	if (!timespec64_valid(&tu64))
+		return -EINVAL;
+
+	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
+	current->restart_block.nanosleep.compat_rmtp = rmtp;
+	return hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+}
+#endif
+
 /*
  * Functions related to boot-time initialization:
  */