[PATCH] clocksource/drivers/timer-mediatek: Fix "no-cfi indirect call" warning

[Luca Leonardo Scorcia <l.scorcia@gmail.com>]

After converting the driver to OF probing, kernel-test-robot reported the
following new warning:

vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

This occurs because of_device_get_match_data() returns NULL when
CONFIG_OF is disabled, which results in LLVM dropping the kCFI setup
since it knows that there is no valid target for this call. Adding a
check for a NULL timer_init avoids the warning and it makes the probe
more robust since of_device_get_match_data() could return NULL even
when CONFIG_OF=y.

Fixes: 7a097aba7255 ("clocksource/drivers/timer-mediatek: Convert to OF probing")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202610290223.iOEGeDs2-lkp@intel.com/
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Luca Leonardo Scorcia <l.scorcia@gmail.com>
---
 drivers/clocksource/timer-mediatek.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index 842d6ee4259e..e772f5fe8742 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -353,6 +353,9 @@ static int mtk_timer_probe(struct platform_device *pdev)
 	int (*timer_init)(struct platform_device *pdev);
 
 	timer_init = of_device_get_match_data(&pdev->dev);
+	if (!timer_init)
+		return -ENODEV;
+
 	return timer_init(pdev);
 }
 
-- 
2.43.0