Commit d6bd0e6b authored by Ralf Baechle's avatar Ralf Baechle
Browse files

[MIPS] Protect more of timer_interrupt() by xtime_lock. 


    
From Dave Johnson <djohnson+linuxmips@sw.starentnetworks.com>:

* do_timer() expects the arch-specific handler to take the lock as it
  modifies jiffies[_64] and xtime.
* writing timerhi/lo in timer_interrupt() will mess up
  fixed_rate_gettimeoffset() which reads timerhi/lo.
    
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 966f4406

arch/mips/kernel/time.c

+4 −2
Original line number Diff line number Diff line
@@ -424,6 +424,8 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) 
	unsigned long j;

	unsigned int count;



	write_seqlock(&xtime_lock);



	count = mips_hpt_read();

	mips_timer_ack();
@@ -441,7 +443,6 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) 
	 * CMOS clock accordingly every ~11 minutes. rtc_set_time() has to be

	 * called as close as possible to 500 ms before the new second starts.

	 */

	write_seqlock(&xtime_lock);

	if (ntp_synced() &&

	    xtime.tv_sec > last_rtc_update + 660 &&

	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
@@ -453,7 +454,6 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) 
			last_rtc_update = xtime.tv_sec - 600;

		}

	}

	write_sequnlock(&xtime_lock);



	/*

	 * If jiffies has overflown in this timer_interrupt, we must
@@ -496,6 +496,8 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) 
		}

	}



	write_sequnlock(&xtime_lock);



	/*

	 * In UP mode, we call local_timer_interrupt() to do profiling

	 * and process accouting.

CRA Git | Maintained and supported by SUSTech CRA and CCSE