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-rw-r--r--arch/powerpc/kernel/time.c197
1 files changed, 37 insertions, 160 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 0441bbdadbd..ccb8759c853 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -149,16 +149,6 @@ unsigned long tb_ticks_per_usec = 100; /* sane default */
EXPORT_SYMBOL(tb_ticks_per_usec);
unsigned long tb_ticks_per_sec;
EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
-u64 tb_to_xs;
-unsigned tb_to_us;
-
-#define TICKLEN_SCALE NTP_SCALE_SHIFT
-static u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
-static u64 ticklen_to_xs; /* 0.64 fraction */
-
-/* If last_tick_len corresponds to about 1/HZ seconds, then
- last_tick_len << TICKLEN_SHIFT will be about 2^63. */
-#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL_GPL(rtc_lock);
@@ -174,7 +164,6 @@ unsigned long ppc_proc_freq;
EXPORT_SYMBOL(ppc_proc_freq);
unsigned long ppc_tb_freq;
-static u64 tb_last_jiffy __cacheline_aligned_in_smp;
static DEFINE_PER_CPU(u64, last_jiffy);
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
@@ -423,30 +412,6 @@ void udelay(unsigned long usecs)
}
EXPORT_SYMBOL(udelay);
-static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
- u64 new_tb_to_xs)
-{
- /*
- * tb_update_count is used to allow the userspace gettimeofday code
- * to assure itself that it sees a consistent view of the tb_to_xs and
- * stamp_xsec variables. It reads the tb_update_count, then reads
- * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
- * the two values of tb_update_count match and are even then the
- * tb_to_xs and stamp_xsec values are consistent. If not, then it
- * loops back and reads them again until this criteria is met.
- * We expect the caller to have done the first increment of
- * vdso_data->tb_update_count already.
- */
- vdso_data->tb_orig_stamp = new_tb_stamp;
- vdso_data->stamp_xsec = new_stamp_xsec;
- vdso_data->tb_to_xs = new_tb_to_xs;
- vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
- vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
- vdso_data->stamp_xtime = xtime;
- smp_wmb();
- ++(vdso_data->tb_update_count);
-}
-
#ifdef CONFIG_SMP
unsigned long profile_pc(struct pt_regs *regs)
{
@@ -470,7 +435,6 @@ EXPORT_SYMBOL(profile_pc);
static int __init iSeries_tb_recal(void)
{
- struct div_result divres;
unsigned long titan, tb;
/* Make sure we only run on iSeries */
@@ -501,10 +465,7 @@ static int __init iSeries_tb_recal(void)
tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
tb_ticks_per_sec = new_tb_ticks_per_sec;
calc_cputime_factors();
- div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
- tb_to_xs = divres.result_low;
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
- vdso_data->tb_to_xs = tb_to_xs;
setup_cputime_one_jiffy();
}
else {
@@ -667,27 +628,9 @@ void timer_interrupt(struct pt_regs * regs)
trace_timer_interrupt_exit(regs);
}
-void wakeup_decrementer(void)
-{
- unsigned long ticks;
-
- /*
- * The timebase gets saved on sleep and restored on wakeup,
- * so all we need to do is to reset the decrementer.
- */
- ticks = tb_ticks_since(__get_cpu_var(last_jiffy));
- if (ticks < tb_ticks_per_jiffy)
- ticks = tb_ticks_per_jiffy - ticks;
- else
- ticks = 1;
- set_dec(ticks);
-}
-
#ifdef CONFIG_SUSPEND
-void generic_suspend_disable_irqs(void)
+static void generic_suspend_disable_irqs(void)
{
- preempt_disable();
-
/* Disable the decrementer, so that it doesn't interfere
* with suspending.
*/
@@ -697,12 +640,9 @@ void generic_suspend_disable_irqs(void)
set_dec(0x7fffffff);
}
-void generic_suspend_enable_irqs(void)
+static void generic_suspend_enable_irqs(void)
{
- wakeup_decrementer();
-
local_irq_enable();
- preempt_enable();
}
/* Overrides the weak version in kernel/power/main.c */
@@ -722,23 +662,6 @@ void arch_suspend_enable_irqs(void)
}
#endif
-#ifdef CONFIG_SMP
-void __init smp_space_timers(unsigned int max_cpus)
-{
- int i;
- u64 previous_tb = per_cpu(last_jiffy, boot_cpuid);
-
- /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
- previous_tb -= tb_ticks_per_jiffy;
-
- for_each_possible_cpu(i) {
- if (i == boot_cpuid)
- continue;
- per_cpu(last_jiffy, i) = previous_tb;
- }
-}
-#endif
-
/*
* Scheduler clock - returns current time in nanosec units.
*
@@ -873,10 +796,37 @@ static cycle_t timebase_read(struct clocksource *cs)
return (cycle_t)get_tb();
}
+static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
+ u64 new_tb_to_xs, struct timespec *now,
+ u32 frac_sec)
+{
+ /*
+ * tb_update_count is used to allow the userspace gettimeofday code
+ * to assure itself that it sees a consistent view of the tb_to_xs and
+ * stamp_xsec variables. It reads the tb_update_count, then reads
+ * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
+ * the two values of tb_update_count match and are even then the
+ * tb_to_xs and stamp_xsec values are consistent. If not, then it
+ * loops back and reads them again until this criteria is met.
+ * We expect the caller to have done the first increment of
+ * vdso_data->tb_update_count already.
+ */
+ vdso_data->tb_orig_stamp = new_tb_stamp;
+ vdso_data->stamp_xsec = new_stamp_xsec;
+ vdso_data->tb_to_xs = new_tb_to_xs;
+ vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
+ vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+ vdso_data->stamp_xtime = *now;
+ vdso_data->stamp_sec_fraction = frac_sec;
+ smp_wmb();
+ ++(vdso_data->tb_update_count);
+}
+
void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
u32 mult)
{
u64 t2x, stamp_xsec;
+ u32 frac_sec;
if (clock != &clocksource_timebase)
return;
@@ -888,10 +838,14 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
/* XXX this assumes clock->shift == 22 */
/* 4611686018 ~= 2^(20+64-22) / 1e9 */
t2x = (u64) mult * 4611686018ULL;
- stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
+ stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
do_div(stamp_xsec, 1000000000);
- stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
- update_gtod(clock->cycle_last, stamp_xsec, t2x);
+ stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
+
+ BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
+ /* this is tv_nsec / 1e9 as a 0.32 fraction */
+ frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
+ update_gtod(clock->cycle_last, stamp_xsec, t2x, wall_time, frac_sec);
}
void update_vsyscall_tz(void)
@@ -1007,15 +961,13 @@ void secondary_cpu_time_init(void)
/* This function is only called on the boot processor */
void __init time_init(void)
{
- unsigned long flags;
struct div_result res;
- u64 scale, x;
+ u64 scale;
unsigned shift;
if (__USE_RTC()) {
/* 601 processor: dec counts down by 128 every 128ns */
ppc_tb_freq = 1000000000;
- tb_last_jiffy = get_rtcl();
} else {
/* Normal PowerPC with timebase register */
ppc_md.calibrate_decr();
@@ -1023,50 +975,15 @@ void __init time_init(void)
ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
- tb_last_jiffy = get_tb();
}
tb_ticks_per_jiffy = ppc_tb_freq / HZ;
tb_ticks_per_sec = ppc_tb_freq;
tb_ticks_per_usec = ppc_tb_freq / 1000000;
- tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
calc_cputime_factors();
setup_cputime_one_jiffy();
/*
- * Calculate the length of each tick in ns. It will not be
- * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
- * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
- * rounded up.
- */
- x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1;
- do_div(x, ppc_tb_freq);
- tick_nsec = x;
- last_tick_len = x << TICKLEN_SCALE;
-
- /*
- * Compute ticklen_to_xs, which is a factor which gets multiplied
- * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
- * It is computed as:
- * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
- * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
- * which turns out to be N = 51 - SHIFT_HZ.
- * This gives the result as a 0.64 fixed-point fraction.
- * That value is reduced by an offset amounting to 1 xsec per
- * 2^31 timebase ticks to avoid problems with time going backwards
- * by 1 xsec when we do timer_recalc_offset due to losing the
- * fractional xsec. That offset is equal to ppc_tb_freq/2^51
- * since there are 2^20 xsec in a second.
- */
- div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
- tb_ticks_per_jiffy << SHIFT_HZ, &res);
- div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
- ticklen_to_xs = res.result_low;
-
- /* Compute tb_to_xs from tick_nsec */
- tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs);
-
- /*
* Compute scale factor for sched_clock.
* The calibrate_decr() function has set tb_ticks_per_sec,
* which is the timebase frequency.
@@ -1087,21 +1004,14 @@ void __init time_init(void)
/* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
boot_tb = get_tb_or_rtc();
- write_seqlock_irqsave(&xtime_lock, flags);
-
/* If platform provided a timezone (pmac), we correct the time */
if (timezone_offset) {
sys_tz.tz_minuteswest = -timezone_offset / 60;
sys_tz.tz_dsttime = 0;
}
- vdso_data->tb_orig_stamp = tb_last_jiffy;
vdso_data->tb_update_count = 0;
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
- vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
- vdso_data->tb_to_xs = tb_to_xs;
-
- write_sequnlock_irqrestore(&xtime_lock, flags);
/* Start the decrementer on CPUs that have manual control
* such as BookE
@@ -1195,39 +1105,6 @@ void to_tm(int tim, struct rtc_time * tm)
GregorianDay(tm);
}
-/* Auxiliary function to compute scaling factors */
-/* Actually the choice of a timebase running at 1/4 the of the bus
- * frequency giving resolution of a few tens of nanoseconds is quite nice.
- * It makes this computation very precise (27-28 bits typically) which
- * is optimistic considering the stability of most processor clock
- * oscillators and the precision with which the timebase frequency
- * is measured but does not harm.
- */
-unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale)
-{
- unsigned mlt=0, tmp, err;
- /* No concern for performance, it's done once: use a stupid
- * but safe and compact method to find the multiplier.
- */
-
- for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
- if (mulhwu(inscale, mlt|tmp) < outscale)
- mlt |= tmp;
- }
-
- /* We might still be off by 1 for the best approximation.
- * A side effect of this is that if outscale is too large
- * the returned value will be zero.
- * Many corner cases have been checked and seem to work,
- * some might have been forgotten in the test however.
- */
-
- err = inscale * (mlt+1);
- if (err <= inscale/2)
- mlt++;
- return mlt;
-}
-
/*
* Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
* result.
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-02 20:39:46 +0000