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author | Rob Barnes <robbarnes@google.com> | 2022-06-24 10:28:31 -0600 |
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committer | Martin L Roth <gaumless@gmail.com> | 2022-08-13 17:20:11 +0000 |
commit | b11f9f7e162759cf5ae0f033e125e9158520030d (patch) | |
tree | 6c53aac2b789995fc6ea1af186f53274402310a4 /src/mainboard/lenovo/t410 | |
parent | 175445b4bbb16b8eedc2f6bd1b3ec37cb1095bf1 (diff) |
timer: Switch mono_time to uint64_t
A 32-bit long storing microseconds will rollover every ~1.19 hours.
This can cause stopwatch to misbehave, causing unexpected failures.
If the current field in stopwatch is near 2^31, the expires field may
rollover when initialized. If this occurs, stopwatch_expired() will
instantly return true.
If current and expires fields are near 2^31, the current field could
rollover before being checked. In this case, stopwatch_expired() will
not return true for over an hour. Also stopwatch_duration_usecs() will
return a large negative duration.
This issue has only been observed in SMM since it never takes more
than 35 minutes to boot.
Switching to uint64_t mitigates this issue since it will not rollover
for over 500K+ years. The raw TSC would rollover sooner than this,
~200 years, depending on the tick frequency.
BUG=b:237082996
BRANCH=All
TEST=Boot Nipperkin
Change-Id: I4c24894718f093ac7cd1e434410bc64e6436869a
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65403
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Martin L Roth <gaumless@gmail.com>
Diffstat (limited to 'src/mainboard/lenovo/t410')
0 files changed, 0 insertions, 0 deletions