[RFC][PATCH] ppc misusing NTP's time_offset value

[john stultz]

Hey everyone,

	As part of my timeofday rework, I've been looking at the NTP code and I
noticed that the PPC architecture is apparently misusing the NTP's
time_offset (it is a terrible name!) value as some form of timezone
offset. This could cause problems when time_offset changed by the NTP
code.
	
	This patch changes the PPC code so it uses a more clear local variable:
timezone_offset.

Could a PPC maintainer verify this is correct?

Let me know if you have any comments or feedback.

thanks
-john

Signed-off-by: John Stultz <johnstul at us.ibm.com>

diff --git a/arch/ppc/kernel/time.c b/arch/ppc/kernel/time.c
--- a/arch/ppc/kernel/time.c
+++ b/arch/ppc/kernel/time.c
@@ -90,6 +90,9 @@ unsigned long tb_to_ns_scale;
 
 extern unsigned long wall_jiffies;
 
+/* used for timezone offset */
+static long timezone_offset;
+
 DEFINE_SPINLOCK(rtc_lock);
 
 EXPORT_SYMBOL(rtc_lock);
@@ -171,7 +174,7 @@ void timer_interrupt(struct pt_regs * re
 		     xtime.tv_sec - last_rtc_update >= 659 &&
 		     abs((xtime.tv_nsec / 1000) - (1000000-1000000/HZ)) < 500000/HZ &&
 		     jiffies - wall_jiffies == 1) {
-		  	if (ppc_md.set_rtc_time(xtime.tv_sec+1 + time_offset) == 0)
+		  	if (ppc_md.set_rtc_time(xtime.tv_sec+1 + timezone_offset) == 0)
 				last_rtc_update = xtime.tv_sec+1;
 			else
 				/* Try again one minute later */
@@ -284,7 +287,7 @@ void __init time_init(void)
 	unsigned old_stamp, stamp, elapsed;
 
         if (ppc_md.time_init != NULL)
-                time_offset = ppc_md.time_init();
+                timezone_offset = ppc_md.time_init();
 
 	if (__USE_RTC()) {
 		/* 601 processor: dec counts down by 128 every 128ns */
@@ -329,10 +332,10 @@ void __init time_init(void)
 	set_dec(tb_ticks_per_jiffy);
 
 	/* If platform provided a timezone (pmac), we correct the time */
-        if (time_offset) {
-		sys_tz.tz_minuteswest = -time_offset / 60;
+        if (timezone_offset) {
+		sys_tz.tz_minuteswest = -timezone_offset / 60;
 		sys_tz.tz_dsttime = 0;
-		xtime.tv_sec -= time_offset;
+		xtime.tv_sec -= timezone_offset;
         }
         set_normalized_timespec(&wall_to_monotonic,
                                 -xtime.tv_sec, -xtime.tv_nsec);