timekeeping: Increase granularity of read_persistent_clock()

The persistent clock of some architectures (e.g. s390) have a
better granularity than seconds. To reduce the delta between the
host clock and the guest clock in a virtualized system change the 
read_persistent_clock function to return a struct timespec.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
LKML-Reference: <20090814134811.013873340@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

8 files changed, 35 insertions, 18 deletions

diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index 463136e6685..02f505f23c3 100644
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -18,7 +18,7 @@
 #include <asm/dec/ioasic.h>
 #include <asm/dec/machtype.h>
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
         unsigned int year, mon, day, hour, min, sec, real_year;
         unsigned long flags;
@@ -53,7 +53,8 @@ unsigned long read_persistent_clock(void)
 
         year += real_year - 72 + 2000;
 
-        return mktime(year, mon, day, hour, min, sec);
+        ts->tv_sec = mktime(year, mon, day, hour, min, sec);
+        ts->tv_nsec = 0;
 }
 
 /*
diff --git a/arch/mips/lasat/ds1603.c b/arch/mips/lasat/ds1603.c
index 52cb1436a12..c6fd96ff118 100644
--- a/arch/mips/lasat/ds1603.c
+++ b/arch/mips/lasat/ds1603.c
@@ -135,7 +135,7 @@ static void rtc_end_op(void)
         lasat_ndelay(1000);
 }
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
         unsigned long word;
         unsigned long flags;
@@ -147,7 +147,8 @@ unsigned long read_persistent_clock(void)
         rtc_end_op();
         spin_unlock_irqrestore(&rtc_lock, flags);
 
-        return word;
+        ts->tv_sec = word;
+        ts->tv_nsec = 0;
 }
 
 int rtc_mips_set_mmss(unsigned long time)
diff --git a/arch/mips/lasat/sysctl.c b/arch/mips/lasat/sysctl.c
index 8f88886feb1..3f04d4c406b 100644
--- a/arch/mips/lasat/sysctl.c
+++ b/arch/mips/lasat/sysctl.c
@@ -92,10 +92,12 @@ static int rtctmp;
 int proc_dolasatrtc(ctl_table *table, int write, struct file *filp,
                        void *buffer, size_t *lenp, loff_t *ppos)
 {
+        struct timespec ts;
         int r;
 
         if (!write) {
-                rtctmp = read_persistent_clock();
+                read_persistent_clock(&ts);
+                rtctmp = ts.tv_sec;
                 /* check for time < 0 and set to 0 */
                 if (rtctmp < 0)
                         rtctmp = 0;
@@ -134,9 +136,11 @@ int sysctl_lasat_rtc(ctl_table *table,
                     void *oldval, size_t *oldlenp,
                     void *newval, size_t newlen)
 {
+        struct timespec ts;
         int r;
 
-        rtctmp = read_persistent_clock();
+        read_persistent_clock(&ts);
+        rtctmp = ts.tv_sec;
         if (rtctmp < 0)
                 rtctmp = 0;
         r = sysctl_intvec(table, oldval, oldlenp, newval, newlen);
diff --git a/arch/mips/lemote/lm2e/setup.c b/arch/mips/lemote/lm2e/setup.c
index ebd6ceaef2f..24b355df612 100644
--- a/arch/mips/lemote/lm2e/setup.c
+++ b/arch/mips/lemote/lm2e/setup.c
@@ -54,9 +54,10 @@ void __init plat_time_init(void)
         mips_hpt_frequency = cpu_clock_freq / 2;
 }
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
-        return mc146818_get_cmos_time();
+        ts->tv_sec = mc146818_get_cmos_time();
+        ts->tv_nsec = 0;
 }
 
 void (*__wbflush)(void);
diff --git a/arch/mips/mti-malta/malta-time.c b/arch/mips/mti-malta/malta-time.c
index 0b97d47691f..3c6f190aa61 100644
--- a/arch/mips/mti-malta/malta-time.c
+++ b/arch/mips/mti-malta/malta-time.c
@@ -100,9 +100,10 @@ static unsigned int __init estimate_cpu_frequency(void)
         return count;
 }
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
-        return mc146818_get_cmos_time();
+        ts->tv_sec = mc146818_get_cmos_time();
+        ts->tv_nsec = 0;
 }
 
 static void __init plat_perf_setup(void)
diff --git a/arch/mips/pmc-sierra/yosemite/setup.c b/arch/mips/pmc-sierra/yosemite/setup.c
index 2d3c0dca275..3498ac9c35a 100644
--- a/arch/mips/pmc-sierra/yosemite/setup.c
+++ b/arch/mips/pmc-sierra/yosemite/setup.c
@@ -70,7 +70,7 @@ void __init bus_error_init(void)
 }
 
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
         unsigned int year, month, day, hour, min, sec;
         unsigned long flags;
@@ -92,7 +92,8 @@ unsigned long read_persistent_clock(void)
         m48t37_base->control = 0x00;
         spin_unlock_irqrestore(&rtc_lock, flags);
 
-        return mktime(year, month, day, hour, min, sec);
+        ts->tv_sec = mktime(year, month, day, hour, min, sec);
+        ts->tv_nsec = 0;
 }
 
 int rtc_mips_set_time(unsigned long tim)
diff --git a/arch/mips/sibyte/swarm/setup.c b/arch/mips/sibyte/swarm/setup.c
index 672e45d495a..623ffc933c4 100644
--- a/arch/mips/sibyte/swarm/setup.c
+++ b/arch/mips/sibyte/swarm/setup.c
@@ -87,19 +87,26 @@ enum swarm_rtc_type {
 
 enum swarm_rtc_type swarm_rtc_type;
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
+        unsigned long sec;
+
         switch (swarm_rtc_type) {
         case RTC_XICOR:
-                return xicor_get_time();
+                sec = xicor_get_time();
+                break;
 
         case RTC_M4LT81:
-                return m41t81_get_time();
+                sec = m41t81_get_time();
+                break;
 
         case RTC_NONE:
         default:
-                return mktime(2000, 1, 1, 0, 0, 0);
+                sec = mktime(2000, 1, 1, 0, 0, 0);
+                break;
         }
+        ts->tv_sec = sec;
+        tv->tv_nsec = 0;
 }
 
 int rtc_mips_set_time(unsigned long sec)
diff --git a/arch/mips/sni/time.c b/arch/mips/sni/time.c
index 0d9ec1a5c24..62df6a598e0 100644
--- a/arch/mips/sni/time.c
+++ b/arch/mips/sni/time.c
@@ -182,7 +182,8 @@ void __init plat_time_init(void)
         setup_pit_timer();
 }
 
-unsigned long read_persistent_clock(void)
+void read_persistent_clock(struct timespec *ts)
 {
-        return -1;
+        ts->tv_sec = -1;
+        ts->tv_nsec = 0;
 }