posix-timers: Make clock_getres and clock_get mandatory

Richard said: "I would think that we can require k_clocks to provide
the read function. This could be checked and enforced in
register_posix_clock()."

Add checks for clock_getres and clock_get in the register function.

Suggested-by: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 12 insertions, 3 deletions

diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index d9e5edfe8a1b..7f66143d1ce5 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -485,7 +485,18 @@ static struct pid *good_sigevent(sigevent_t * event)
 void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
 {
         if ((unsigned) clock_id >= MAX_CLOCKS) {
-                printk("POSIX clock register failed for clock_id %d\n",
+                printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
+                       clock_id);
+                return;
+        }
+
+        if (!new_clock->clock_get) {
+                printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n",
+                       clock_id);
+                return;
+        }
+        if (!new_clock->clock_getres) {
+                printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n",
                        clock_id);
                 return;
         }
@@ -961,8 +972,6 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
 
         if (!kc)
                 return -EINVAL;
-        if (!kc->clock_get)
-                return -EOPNOTSUPP;
 
         error = kc->clock_get(which_clock, &kernel_tp);