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Commit 5329e13d authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
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[PATCH] x86_64: Fix get_cmos_time() 



Due to a broken condition, the body of the loop that is intended to wait for
the Update-In-Progress bit to get set and then cleared again was never
entered; in fact, the entire loop was optimized out by the compiler. Here is
a change to fix the condition (and to also move the initialization of locals
out of the spin lock protected region).

Signed-Off-By: default avatarJan Beulich <jbeulich@novell.com>

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bdf2b1c9

arch/x86_64/kernel/time.c

+4 −7
Original line number Diff line number Diff line
@@ -504,8 +504,8 @@ unsigned long long sched_clock(void) 


static unsigned long get_cmos_time(void)

{

	unsigned int timeout, year, mon, day, hour, min, sec;

	unsigned char last, this;

	unsigned int timeout = 1000000, year, mon, day, hour, min, sec;

	unsigned char uip = 0, this = 0;

	unsigned long flags;



/*
@@ -518,11 +518,8 @@ static unsigned long get_cmos_time(void) 


	spin_lock_irqsave(&rtc_lock, flags);



	timeout = 1000000;

	last = this = 0;



	while (timeout && last && !this) {

		last = this;

	while (timeout && (!uip || this)) {

		uip |= this;

		this = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP;

		timeout--;

	}