x86/hpet: Use the FSEC_PER_SEC constant for femto-second periods
The current computation, introduced with f12a15be63
, of FSEC_PER_SEC using
the multiplication of (FSEC_PER_NSEC * NSEC_PER_SEC) is performed only
with 32bit integers on small machines, resulting in an overflow and a
*very* short intervals being programmed. An interrupt storm follows.
Note that we also have to specify FSEC_PER_SEC as being long long to
overcome the same limitations.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Родитель
deda2e8196
Коммит
4936a3b90d
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@ -582,7 +582,7 @@ static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
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* scaled math multiplication factor for nanosecond to hpet tick
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* conversion.
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*/
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hpet_freq = 1000000000000000ULL;
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hpet_freq = FSEC_PER_SEC;
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do_div(hpet_freq, hpet_period);
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evt->mult = div_sc((unsigned long) hpet_freq,
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NSEC_PER_SEC, evt->shift);
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@ -837,7 +837,7 @@ static int hpet_clocksource_register(void)
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* cyc/sec = FSEC_PER_SEC/hpet_period(fsec/cyc)
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* cyc/sec = (FSEC_PER_NSEC * NSEC_PER_SEC)/hpet_period
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*/
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hpet_freq = FSEC_PER_NSEC * NSEC_PER_SEC;
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hpet_freq = FSEC_PER_SEC;
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do_div(hpet_freq, hpet_period);
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clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq);
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@ -38,7 +38,7 @@ extern struct timezone sys_tz;
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#define NSEC_PER_MSEC 1000000L
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#define USEC_PER_SEC 1000000L
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#define NSEC_PER_SEC 1000000000L
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#define FSEC_PER_SEC 1000000000000000L
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#define FSEC_PER_SEC 1000000000000000LL
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#define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
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