Attachment 301758 Details for Bug 434947 – Fix detection of need for time adjustment. v2

Fix detection of need for time adjustment. v2

bugzilla-43828.patch (text/plain), 3.56 KB, created by IBM Bug Proxy on 2008-04-09 07:32:40 UTC

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Creator: IBM Bug Proxy

Created: 2008-04-09 07:32:40 UTC

Size: 3.56 KB

patch

obsolete

>commit 0b221e6a9448c42906aa7e3bfa81b3ac2865055c
>Author: Tony Breeds <tony@bakeyournoodle.com>
>Date:   Wed Apr 9 17:17:49 2008 +1000
>
>    [POWERPC] Call ppc_adjtimex() when asked to adjust the time in ADJ_OFFSET_SINGLESHOT mode.
>    
>    When making the adjtimex() system call in ADJ_OFFSET_SINGLESHOT, we fail
>    to correctly detect that time needs to be adjusted.  This patch checks
>    the current time step at the begining of a decrementer tick and adjusts
>    the various timeing paramenters to cope with the requested change in
>    time.  When we have successfully adjusted time as requested revert to
>    the "stable" values.
>    
>    Fixes both the 32-bit (compat) and 64-bit cases.
>    
>    Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
>
>diff --git a/arch/ppc64/kernel/sys_ppc32.c b/arch/ppc64/kernel/sys_ppc32.c
>index ed58c85..cbc2eaa 100644
>--- a/arch/ppc64/kernel/sys_ppc32.c
>+++ b/arch/ppc64/kernel/sys_ppc32.c
>@@ -291,7 +291,6 @@ struct timex32 {
> };
> 
> extern int do_adjtimex(struct timex *);
>-extern void ppc_adjtimex(void);
> 
> asmlinkage long sys32_adjtimex(struct timex32 __user *utp)
> {
>@@ -324,9 +323,6 @@ asmlinkage long sys32_adjtimex(struct timex32 __user *utp)
> 
> 	ret = do_adjtimex(&txc);
> 
>-	/* adjust the conversion of TB to time of day to track adjtimex */
>-	ppc_adjtimex();
>-
> 	if(put_user(txc.modes, &utp->modes) ||
> 	   __put_user(txc.offset, &utp->offset) ||
> 	   __put_user(txc.freq, &utp->freq) ||
>diff --git a/arch/ppc64/kernel/time.c b/arch/ppc64/kernel/time.c
>index 3c51a36..9c0457d 100644
>--- a/arch/ppc64/kernel/time.c
>+++ b/arch/ppc64/kernel/time.c
>@@ -107,6 +107,7 @@ extern struct timezone sys_tz;
> void ppc_adjtimex(void);
> 
> static unsigned adjusting_time = 0;
>+static long time_adjust_step = 0;
> 
> static __inline__ void timer_check_rtc(void)
> {
>@@ -237,6 +238,26 @@ static void iSeries_tb_recal(void)
> 
> unsigned long tb_last_stamp __cacheline_aligned_in_smp;
> 
>+int get_time_step(void)
>+{
>+	int tmp_step;
>+
>+	tmp_step = time_adjust;
>+	if (tmp_step) {
>+		/* We are doing an adjtime thing.
>+		 *
>+		 * Limit the amount of the step to be in the range
>+		 * -tickadj .. +tickadj
>+		 */
>+		if (time_adjust > tickadj)
>+			tmp_step = tickadj;
>+		else if (time_adjust < -tickadj)
>+			tmp_step = -tickadj;
>+	}
>+
>+	return tmp_step;
>+}
>+
> /*
>  * timer_interrupt - gets called when the decrementer overflows,
>  * with interrupts disabled.
>@@ -244,6 +265,7 @@ unsigned long tb_last_stamp __cacheline_aligned_in_smp;
> int timer_interrupt(struct pt_regs * regs)
> {
> 	int next_dec;
>+	int current_step;
> 	unsigned long cur_tb;
> 	struct paca_struct *lpaca = get_paca();
> 	unsigned long cpu = smp_processor_id();
>@@ -280,8 +302,11 @@ int timer_interrupt(struct pt_regs * regs)
> 			timer_sync_xtime( cur_tb );
> 			timer_check_rtc();
> 			write_sequnlock(&xtime_lock);
>-			if ( adjusting_time && (time_adjust == 0) )
>+			current_step = get_time_step();
>+			if ( current_step != time_adjust_step ) {
>+				time_adjust_step = current_step;
> 				ppc_adjtimex();
>+			}
> 		}
> 		lpaca->next_jiffy_update_tb += tb_ticks_per_jiffy;
> 	}
>diff --git a/include/linux/timex.h b/include/linux/timex.h
>index ee8cafa..9b57ac3 100644
>--- a/include/linux/timex.h
>+++ b/include/linux/timex.h
>@@ -301,6 +301,7 @@ extern long time_esterror;	/* estimated error */
> extern long time_phase;		/* phase offset (scaled us) */
> extern long time_freq;		/* frequency offset (scaled ppm) */
> extern long time_adj;		/* tick adjust (scaled 1 / HZ) */
>+extern int tickadj;		/* maximal value (in usec) adjustable / tick */
> extern long time_reftime;	/* time at last adjustment (s) */
> 
> extern long time_adjust;	/* The amount of adjtime left */

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Attachments on bug 434947: 301757 | 301758