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Commit b7ec15bd authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: virtualized time fix 



With the current timekeeping, !CONFIG_UML_REAL_TIME_CLOCK has
inconsistent behavior.  Previously, gettimeofday could be (and was)
isolated from the clock ticking.  Now, it's not, so when
CONFIG_UML_REAL_TIME_CLOCK is disabled, gettimeofday must progress in
lockstep with the clock, making it fully virtual.

Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 83ff7df5

arch/um/kernel/time.c

+12 −2
Original line number Diff line number Diff line
@@ -34,8 +34,8 @@ unsigned long long sched_clock(void) 
	return (unsigned long long)jiffies_64 * (1000000000 / HZ);

}



static unsigned long long prev_nsecs[NR_CPUS];

#ifdef CONFIG_UML_REAL_TIME_CLOCK

static unsigned long long prev_nsecs[NR_CPUS];

static long long delta[NR_CPUS];		/* Deviation per interval */

#endif
@@ -94,7 +94,12 @@ irqreturn_t um_timer(int irq, void *dev) 


	do_timer(1);



#ifdef CONFIG_UML_REAL_TIME_CLOCK

	nsecs = get_time();

#else

	nsecs = (unsigned long long) xtime.tv_sec * BILLION + xtime.tv_nsec +

		BILLION / HZ;

#endif

	xtime.tv_sec = nsecs / NSEC_PER_SEC;

	xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC;
@@ -127,13 +132,18 @@ void time_init(void) 
	nsecs = os_nsecs();

	set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,

				-nsecs % BILLION);

	set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION);

	late_time_init = register_timer;

}



void do_gettimeofday(struct timeval *tv)

{

#ifdef CONFIG_UML_REAL_TIME_CLOCK

	unsigned long long nsecs = get_time();



#else

	unsigned long long nsecs = (unsigned long long) xtime.tv_sec * BILLION +

		xtime.tv_nsec;

#endif

	tv->tv_sec = nsecs / NSEC_PER_SEC;

	/* Careful about calculations here - this was originally done as

	 * (nsecs - tv->tv_sec * NSEC_PER_SEC) / NSEC_PER_USEC