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kern/i386/tsc_pmtimer: The GRUB menu gets stuck due to failed calibration

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The grub_divmod64() may return 0 but grub_tsc_calibrate_from_pmtimer()
still returns 1 saying calibration succeeded. Of course it is not true.
So, return 0 when grub_divmod64() returns 0. This way other calibration
functions can be called subsequently.

Signed-off-by: Duan Yayong <duanyayong@bytedance.com>
Signed-off-by: Li Yongqiang <liyongqiang@huaqin.com>
Signed-off-by: Sun Ming <simon.sun@huaqin.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Duan Yayong 2024-11-28 11:48:26 +08:00 committed by Daniel Kiper
parent 13f005ed83
commit f2a1f66e72
1 changed files with 10 additions and 0 deletions
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10
grub-core/kern/i386/tsc_pmtimer.c
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@ -143,5 +143,15 @@ grub_tsc_calibrate_from_pmtimer (void)
if (tsc_diff == 0)
return 0;
grub_tsc_rate = grub_divmod64 ((1ULL << 32), tsc_diff, 0);
/*
* Specifically, when the tsc_diff (end_tsc - start_tsc) is greater than (1ULL << 32),
* the result of grub_divmod64() becomes zero, causing grub_tsc_rate to always be zero.
* As a result, grub_tsc_get_time_ms() consistently returns zero, and the GRUB menu
* countdown gets stuck. To resolve this, we return 0 to proceed to the next calibration
* function when grub_tsc_rate is zero.
*/
if (grub_tsc_rate == 0)
return 0;
return 1;
}