tree 08b4bfe87aa4290c00da7d3e185ae3f3747ebf41
parent 72bbc226ed2ef0a46c165a482861fff00dd6d4e1
author Heiko Carstens <hca@linux.ibm.com> 1616613762 +0100
committer Heiko Carstens <hca@linux.ibm.com> 1616705845 +0100

s390/vdso: fix tod_steering_delta type

The s390 specific vdso function __arch_get_hw_counter() is supposed to
consider tod clock steering.

If a tod clock steering event happens and the tod clock is set to a
new value __arch_get_hw_counter() will not return the real tod clock
value but slowly drift it from the old delta until the returned value
finally matches the real tod clock value again.

Unfortunately the type of tod_steering_delta unsigned while it is
supposed to be signed. It depends on if tod_steering_delta is negative
or positive in which direction the vdso code drifts the clock value.

Worst case is now that instead of drifting the clock slowly it will
jump into the opposite direction by a factor of two.

Fix this by simply making tod_steering_delta signed.

Fixes: 4bff8cb54502 ("s390: convert to GENERIC_VDSO")
Cc: <stable@vger.kernel.org> # 5.10
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>