PWN-Hunter/android_kernel_xiaomi_sdm845
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x86: quick TSC calibration, improve

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- make sure the final TSC timestamp is reliable too

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2008-09-04 22:47:47 +02:00
parent 6ac40ed041
commit 4156e9a8ef
1 changed files with 6 additions and 0 deletions
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6
arch/x86/kernel/tsc.c
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@ -316,6 +316,12 @@ static unsigned long quick_pit_calibrate(void)
} }
t2 = get_cycles(); t2 = get_cycles();
/*
* Make sure we can rely on the second TSC timestamp:
*/
if (!pit_expect_msb(--expect))
goto failed;
/* /*
* Ok, if we get here, then we've seen the * Ok, if we get here, then we've seen the
* MSB of the PIT decrement QUICK_PIT_ITERATIONS * MSB of the PIT decrement QUICK_PIT_ITERATIONS