selftests: timers: Fix valid-adjtimex signed left-shift undefined behavior
[ Upstream commit 076361362122a6d8a4c45f172ced5576b2d4a50d ]
The struct adjtimex freq field takes a signed value who's units are in
shifted (<<16) parts-per-million.
Unfortunately for negative adjustments, the straightforward use of:
freq = ppm << 16 trips undefined behavior warnings with clang:
valid-adjtimex.c:66:6: warning: shifting a negative signed value is undefined [-Wshift-negative-value]
-499<<16,
~~~~^
valid-adjtimex.c:67:6: warning: shifting a negative signed value is undefined [-Wshift-negative-value]
-450<<16,
~~~~^
..
Fix it by using a multiply by (1 << 16) instead of shifting negative values
in the valid-adjtimex test case. Align the values for better readability.
Reported-by: Lee Jones <joneslee@google.com>
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20240409202222.2830476-1-jstultz@google.com
Link: https://lore.kernel.org/lkml/0c6d4f0d-2064-4444-986b-1d1ed782135f@collabora.com/
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 968908c39d985bc636e069769772155f66586664)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
1 file changed