* 2 of the License, or (at your option) any later version.
*/
-#include <linux/config.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/security.h>
#include <linux/percpu.h>
#include <linux/rtc.h>
+#include <linux/jiffies.h>
+#include <linux/posix-timers.h>
+#include <linux/irq.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/prom.h>
#include <asm/irq.h>
#include <asm/div64.h>
-#ifdef CONFIG_PPC64
-#include <asm/systemcfg.h>
+#include <asm/smp.h>
+#include <asm/vdso_datapage.h>
#include <asm/firmware.h>
-#endif
+#include <asm/cputime.h>
#ifdef CONFIG_PPC_ISERIES
-#include <asm/iSeries/ItLpQueue.h>
-#include <asm/iSeries/HvCallXm.h>
+#include <asm/iseries/it_lp_queue.h>
+#include <asm/iseries/hv_call_xm.h>
#endif
-u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
+/* powerpc clocksource/clockevent code */
+
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+
+static cycle_t rtc_read(void);
+static struct clocksource clocksource_rtc = {
+ .name = "rtc",
+ .rating = 400,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .mask = CLOCKSOURCE_MASK(64),
+ .shift = 22,
+ .mult = 0, /* To be filled in */
+ .read = rtc_read,
+};
+
+static cycle_t timebase_read(void);
+static struct clocksource clocksource_timebase = {
+ .name = "timebase",
+ .rating = 400,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .mask = CLOCKSOURCE_MASK(64),
+ .shift = 22,
+ .mult = 0, /* To be filled in */
+ .read = timebase_read,
+};
-EXPORT_SYMBOL(jiffies_64);
+#define DECREMENTER_MAX 0x7fffffff
+
+static int decrementer_set_next_event(unsigned long evt,
+ struct clock_event_device *dev);
+static void decrementer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *dev);
+
+static struct clock_event_device decrementer_clockevent = {
+ .name = "decrementer",
+ .rating = 200,
+ .shift = 16,
+ .mult = 0, /* To be filled in */
+ .irq = 0,
+ .set_next_event = decrementer_set_next_event,
+ .set_mode = decrementer_set_mode,
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+};
+
+struct decrementer_clock {
+ struct clock_event_device event;
+ u64 next_tb;
+};
+
+static DEFINE_PER_CPU(struct decrementer_clock, decrementers);
-/* keep track of when we need to update the rtc */
-time_t last_rtc_update;
-extern int piranha_simulator;
#ifdef CONFIG_PPC_ISERIES
-unsigned long iSeries_recal_titan = 0;
-unsigned long iSeries_recal_tb = 0;
-static unsigned long first_settimeofday = 1;
-#endif
+static unsigned long __initdata iSeries_recal_titan;
+static signed long __initdata iSeries_recal_tb;
-/* The decrementer counts down by 128 every 128ns on a 601. */
-#define DECREMENTER_COUNT_601 (1000000000 / HZ)
+/* Forward declaration is only needed for iSereis compiles */
+void __init clocksource_init(void);
+#endif
#define XSEC_PER_SEC (1024*1024)
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;
-unsigned long processor_freq;
+
+#define TICKLEN_SCALE NTP_SCALE_SHIFT
+u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
+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);
-u64 tb_to_ns_scale;
-unsigned tb_to_ns_shift;
+static u64 tb_to_ns_scale __read_mostly;
+static unsigned tb_to_ns_shift __read_mostly;
+static unsigned long boot_tb __read_mostly;
struct gettimeofday_struct do_gtod;
-extern unsigned long wall_jiffies;
-
extern struct timezone sys_tz;
static long timezone_offset;
-void ppc_adjtimex(void);
-
-static unsigned adjusting_time = 0;
-
unsigned long ppc_proc_freq;
+EXPORT_SYMBOL(ppc_proc_freq);
unsigned long ppc_tb_freq;
-#ifdef CONFIG_PPC32 /* XXX for now */
-#define boot_cpuid 0
-#endif
-
-u64 tb_last_jiffy __cacheline_aligned_in_smp;
-unsigned long tb_last_stamp;
+static u64 tb_last_jiffy __cacheline_aligned_in_smp;
+static DEFINE_PER_CPU(u64, last_jiffy);
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
/*
- * Note that on ppc32 this only stores the bottom 32 bits of
- * the timebase value, but that's enough to tell when a jiffy
- * has passed.
+ * Factors for converting from cputime_t (timebase ticks) to
+ * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
+ * These are all stored as 0.64 fixed-point binary fractions.
*/
-DEFINE_PER_CPU(unsigned long, last_jiffy);
-
-static __inline__ void timer_check_rtc(void)
-{
- /*
- * update the rtc when needed, this should be performed on the
- * right fraction of a second. Half or full second ?
- * Full second works on mk48t59 clocks, others need testing.
- * Note that this update is basically only used through
- * the adjtimex system calls. Setting the HW clock in
- * any other way is a /dev/rtc and userland business.
- * This is still wrong by -0.5/+1.5 jiffies because of the
- * timer interrupt resolution and possible delay, but here we
- * hit a quantization limit which can only be solved by higher
- * resolution timers and decoupling time management from timer
- * interrupts. This is also wrong on the clocks
- * which require being written at the half second boundary.
- * We should have an rtc call that only sets the minutes and
- * seconds like on Intel to avoid problems with non UTC clocks.
- */
- if (ppc_md.set_rtc_time && ntp_synced() &&
- xtime.tv_sec - last_rtc_update >= 659 &&
- abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ &&
- jiffies - wall_jiffies == 1) {
- struct rtc_time tm;
- to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
- tm.tm_year -= 1900;
- tm.tm_mon -= 1;
- if (ppc_md.set_rtc_time(&tm) == 0)
- last_rtc_update = xtime.tv_sec + 1;
- else
- /* Try again one minute later */
- last_rtc_update += 60;
- }
+u64 __cputime_jiffies_factor;
+EXPORT_SYMBOL(__cputime_jiffies_factor);
+u64 __cputime_msec_factor;
+EXPORT_SYMBOL(__cputime_msec_factor);
+u64 __cputime_sec_factor;
+EXPORT_SYMBOL(__cputime_sec_factor);
+u64 __cputime_clockt_factor;
+EXPORT_SYMBOL(__cputime_clockt_factor);
+DEFINE_PER_CPU(unsigned long, cputime_last_delta);
+DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta);
+
+static void calc_cputime_factors(void)
+{
+ struct div_result res;
+
+ div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
+ __cputime_jiffies_factor = res.result_low;
+ div128_by_32(1000, 0, tb_ticks_per_sec, &res);
+ __cputime_msec_factor = res.result_low;
+ div128_by_32(1, 0, tb_ticks_per_sec, &res);
+ __cputime_sec_factor = res.result_low;
+ div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
+ __cputime_clockt_factor = res.result_low;
}
/*
- * This version of gettimeofday has microsecond resolution.
+ * Read the PURR on systems that have it, otherwise the timebase.
*/
-static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val)
+static u64 read_purr(void)
{
- unsigned long sec, usec;
- u64 tb_ticks, xsec;
- struct gettimeofday_vars *temp_varp;
- u64 temp_tb_to_xs, temp_stamp_xsec;
+ if (cpu_has_feature(CPU_FTR_PURR))
+ return mfspr(SPRN_PURR);
+ return mftb();
+}
+/*
+ * Read the SPURR on systems that have it, otherwise the purr
+ */
+static u64 read_spurr(u64 purr)
+{
/*
- * These calculations are faster (gets rid of divides)
- * if done in units of 1/2^20 rather than microseconds.
- * The conversion to microseconds at the end is done
- * without a divide (and in fact, without a multiply)
+ * cpus without PURR won't have a SPURR
+ * We already know the former when we use this, so tell gcc
*/
- temp_varp = do_gtod.varp;
- tb_ticks = tb_val - temp_varp->tb_orig_stamp;
- temp_tb_to_xs = temp_varp->tb_to_xs;
- temp_stamp_xsec = temp_varp->stamp_xsec;
- xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs);
- sec = xsec / XSEC_PER_SEC;
- usec = (unsigned long)xsec & (XSEC_PER_SEC - 1);
- usec = SCALE_XSEC(usec, 1000000);
+ if (cpu_has_feature(CPU_FTR_PURR) && cpu_has_feature(CPU_FTR_SPURR))
+ return mfspr(SPRN_SPURR);
+ return purr;
+}
+
+/*
+ * Account time for a transition between system, hard irq
+ * or soft irq state.
+ */
+void account_system_vtime(struct task_struct *tsk)
+{
+ u64 now, nowscaled, delta, deltascaled, sys_time;
+ unsigned long flags;
- tv->tv_sec = sec;
- tv->tv_usec = usec;
+ local_irq_save(flags);
+ now = read_purr();
+ nowscaled = read_spurr(now);
+ delta = now - get_paca()->startpurr;
+ deltascaled = nowscaled - get_paca()->startspurr;
+ get_paca()->startpurr = now;
+ get_paca()->startspurr = nowscaled;
+ if (!in_interrupt()) {
+ /* deltascaled includes both user and system time.
+ * Hence scale it based on the purr ratio to estimate
+ * the system time */
+ sys_time = get_paca()->system_time;
+ if (get_paca()->user_time)
+ deltascaled = deltascaled * sys_time /
+ (sys_time + get_paca()->user_time);
+ delta += sys_time;
+ get_paca()->system_time = 0;
+ }
+ account_system_time(tsk, 0, delta);
+ account_system_time_scaled(tsk, deltascaled);
+ per_cpu(cputime_last_delta, smp_processor_id()) = delta;
+ per_cpu(cputime_scaled_last_delta, smp_processor_id()) = deltascaled;
+ local_irq_restore(flags);
}
-void do_gettimeofday(struct timeval *tv)
+/*
+ * Transfer the user and system times accumulated in the paca
+ * by the exception entry and exit code to the generic process
+ * user and system time records.
+ * Must be called with interrupts disabled.
+ */
+void account_process_tick(struct task_struct *tsk, int user_tick)
{
- if (__USE_RTC()) {
- /* do this the old way */
- unsigned long flags, seq;
- unsigned int sec, nsec, usec, lost;
+ cputime_t utime, utimescaled;
- do {
- seq = read_seqbegin_irqsave(&xtime_lock, flags);
- sec = xtime.tv_sec;
- nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp);
- lost = jiffies - wall_jiffies;
- } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
- usec = nsec / 1000 + lost * (1000000 / HZ);
- while (usec >= 1000000) {
- usec -= 1000000;
- ++sec;
- }
- tv->tv_sec = sec;
- tv->tv_usec = usec;
+ utime = get_paca()->user_time;
+ get_paca()->user_time = 0;
+ account_user_time(tsk, utime);
+
+ utimescaled = cputime_to_scaled(utime);
+ account_user_time_scaled(tsk, utimescaled);
+}
+
+/*
+ * Stuff for accounting stolen time.
+ */
+struct cpu_purr_data {
+ int initialized; /* thread is running */
+ u64 tb; /* last TB value read */
+ u64 purr; /* last PURR value read */
+ u64 spurr; /* last SPURR value read */
+};
+
+/*
+ * Each entry in the cpu_purr_data array is manipulated only by its
+ * "owner" cpu -- usually in the timer interrupt but also occasionally
+ * in process context for cpu online. As long as cpus do not touch
+ * each others' cpu_purr_data, disabling local interrupts is
+ * sufficient to serialize accesses.
+ */
+static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data);
+
+static void snapshot_tb_and_purr(void *data)
+{
+ unsigned long flags;
+ struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data);
+
+ local_irq_save(flags);
+ p->tb = get_tb_or_rtc();
+ p->purr = mfspr(SPRN_PURR);
+ wmb();
+ p->initialized = 1;
+ local_irq_restore(flags);
+}
+
+/*
+ * Called during boot when all cpus have come up.
+ */
+void snapshot_timebases(void)
+{
+ if (!cpu_has_feature(CPU_FTR_PURR))
return;
- }
- __do_gettimeofday(tv, get_tb());
+ on_each_cpu(snapshot_tb_and_purr, NULL, 1);
+}
+
+/*
+ * Must be called with interrupts disabled.
+ */
+void calculate_steal_time(void)
+{
+ u64 tb, purr;
+ s64 stolen;
+ struct cpu_purr_data *pme;
+
+ pme = &__get_cpu_var(cpu_purr_data);
+ if (!pme->initialized)
+ return; /* !CPU_FTR_PURR or early in early boot */
+ tb = mftb();
+ purr = mfspr(SPRN_PURR);
+ stolen = (tb - pme->tb) - (purr - pme->purr);
+ if (stolen > 0)
+ account_steal_time(current, stolen);
+ pme->tb = tb;
+ pme->purr = purr;
}
-EXPORT_SYMBOL(do_gettimeofday);
+#ifdef CONFIG_PPC_SPLPAR
+/*
+ * Must be called before the cpu is added to the online map when
+ * a cpu is being brought up at runtime.
+ */
+static void snapshot_purr(void)
+{
+ struct cpu_purr_data *pme;
+ unsigned long flags;
-/* Synchronize xtime with do_gettimeofday */
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ local_irq_save(flags);
+ pme = &__get_cpu_var(cpu_purr_data);
+ pme->tb = mftb();
+ pme->purr = mfspr(SPRN_PURR);
+ pme->initialized = 1;
+ local_irq_restore(flags);
+}
-static inline void timer_sync_xtime(unsigned long cur_tb)
+#endif /* CONFIG_PPC_SPLPAR */
+
+#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
+#define calc_cputime_factors()
+#define calculate_steal_time() do { } while (0)
+#endif
+
+#if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
+#define snapshot_purr() do { } while (0)
+#endif
+
+/*
+ * Called when a cpu comes up after the system has finished booting,
+ * i.e. as a result of a hotplug cpu action.
+ */
+void snapshot_timebase(void)
{
-#ifdef CONFIG_PPC64
- /* why do we do this? */
- struct timeval my_tv;
+ __get_cpu_var(last_jiffy) = get_tb_or_rtc();
+ snapshot_purr();
+}
- __do_gettimeofday(&my_tv, cur_tb);
+void __delay(unsigned long loops)
+{
+ unsigned long start;
+ int diff;
- if (xtime.tv_sec <= my_tv.tv_sec) {
- xtime.tv_sec = my_tv.tv_sec;
- xtime.tv_nsec = my_tv.tv_usec * 1000;
+ if (__USE_RTC()) {
+ start = get_rtcl();
+ do {
+ /* the RTCL register wraps at 1000000000 */
+ diff = get_rtcl() - start;
+ if (diff < 0)
+ diff += 1000000000;
+ } while (diff < loops);
+ } else {
+ start = get_tbl();
+ while (get_tbl() - start < loops)
+ HMT_low();
+ HMT_medium();
}
-#endif
}
+EXPORT_SYMBOL(__delay);
+
+void udelay(unsigned long usecs)
+{
+ __delay(tb_ticks_per_usec * usecs);
+}
+EXPORT_SYMBOL(udelay);
+
/*
* There are two copies of tb_to_xs and stamp_xsec so that no
do_gtod.varp = temp_varp;
do_gtod.var_idx = temp_idx;
-#ifdef CONFIG_PPC64
/*
* 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
* 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.
*/
- ++(systemcfg->tb_update_count);
+ 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;
smp_wmb();
- systemcfg->tb_orig_stamp = new_tb_stamp;
- systemcfg->stamp_xsec = new_stamp_xsec;
- systemcfg->tb_to_xs = new_tb_to_xs;
- smp_wmb();
- ++(systemcfg->tb_update_count);
-#endif
-}
-
-/*
- * When the timebase - tb_orig_stamp gets too big, we do a manipulation
- * between tb_orig_stamp and stamp_xsec. The goal here is to keep the
- * difference tb - tb_orig_stamp small enough to always fit inside a
- * 32 bits number. This is a requirement of our fast 32 bits userland
- * implementation in the vdso. If we "miss" a call to this function
- * (interrupt latency, CPU locked in a spinlock, ...) and we end up
- * with a too big difference, then the vdso will fallback to calling
- * the syscall
- */
-static __inline__ void timer_recalc_offset(u64 cur_tb)
-{
- unsigned long offset;
- u64 new_stamp_xsec;
-
- if (__USE_RTC())
- return;
- offset = cur_tb - do_gtod.varp->tb_orig_stamp;
- if ((offset & 0x80000000u) == 0)
- return;
- new_stamp_xsec = do_gtod.varp->stamp_xsec
- + mulhdu(offset, do_gtod.varp->tb_to_xs);
- update_gtod(cur_tb, new_stamp_xsec, do_gtod.varp->tb_to_xs);
+ ++(vdso_data->tb_update_count);
}
#ifdef CONFIG_SMP
* returned by the service processor for the timebase frequency.
*/
-static void iSeries_tb_recal(void)
+static int __init iSeries_tb_recal(void)
{
struct div_result divres;
unsigned long titan, tb;
+
+ /* Make sure we only run on iSeries */
+ if (!firmware_has_feature(FW_FEATURE_ISERIES))
+ return -ENODEV;
+
tb = get_tb();
titan = HvCallXm_loadTod();
if ( iSeries_recal_titan ) {
new_tb_ticks_per_jiffy, sign, tick_diff );
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 );
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
tb_to_xs = divres.result_low;
do_gtod.varp->tb_to_xs = tb_to_xs;
- systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
- systemcfg->tb_to_xs = tb_to_xs;
+ vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
+ vdso_data->tb_to_xs = tb_to_xs;
}
else {
printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
}
iSeries_recal_titan = titan;
iSeries_recal_tb = tb;
+
+ /* Called here as now we know accurate values for the timebase */
+ clocksource_init();
+ return 0;
}
-#endif
+late_initcall(iSeries_tb_recal);
+
+/* Called from platform early init */
+void __init iSeries_time_init_early(void)
+{
+ iSeries_recal_tb = get_tb();
+ iSeries_recal_titan = HvCallXm_loadTod();
+}
+#endif /* CONFIG_PPC_ISERIES */
/*
* For iSeries shared processors, we have to let the hypervisor
*/
void timer_interrupt(struct pt_regs * regs)
{
- int next_dec;
- int cpu = smp_processor_id();
- unsigned long ticks;
+ struct pt_regs *old_regs;
+ struct decrementer_clock *decrementer = &__get_cpu_var(decrementers);
+ struct clock_event_device *evt = &decrementer->event;
+ u64 now;
+
+ /* Ensure a positive value is written to the decrementer, or else
+ * some CPUs will continuue to take decrementer exceptions */
+ set_dec(DECREMENTER_MAX);
#ifdef CONFIG_PPC32
if (atomic_read(&ppc_n_lost_interrupts) != 0)
do_IRQ(regs);
#endif
+ now = get_tb_or_rtc();
+ if (now < decrementer->next_tb) {
+ /* not time for this event yet */
+ now = decrementer->next_tb - now;
+ if (now <= DECREMENTER_MAX)
+ set_dec((int)now);
+ return;
+ }
+ old_regs = set_irq_regs(regs);
irq_enter();
- profile_tick(CPU_PROFILING, regs);
+ calculate_steal_time();
#ifdef CONFIG_PPC_ISERIES
- get_paca()->lppaca.int_dword.fields.decr_int = 0;
+ if (firmware_has_feature(FW_FEATURE_ISERIES))
+ get_lppaca()->int_dword.fields.decr_int = 0;
#endif
- while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu)))
- >= tb_ticks_per_jiffy) {
- /* Update last_jiffy */
- per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy;
- /* Handle RTCL overflow on 601 */
- if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000)
- per_cpu(last_jiffy, cpu) -= 1000000000;
-
- /*
- * We cannot disable the decrementer, so in the period
- * between this cpu's being marked offline in cpu_online_map
- * and calling stop-self, it is taking timer interrupts.
- * Avoid calling into the scheduler rebalancing code if this
- * is the case.
- */
- if (!cpu_is_offline(cpu))
- update_process_times(user_mode(regs));
-
- /*
- * No need to check whether cpu is offline here; boot_cpuid
- * should have been fixed up by now.
- */
- if (cpu != boot_cpuid)
- continue;
-
- write_seqlock(&xtime_lock);
- tb_last_jiffy += tb_ticks_per_jiffy;
- tb_last_stamp = per_cpu(last_jiffy, cpu);
- timer_recalc_offset(tb_last_jiffy);
- do_timer(regs);
- timer_sync_xtime(tb_last_jiffy);
- timer_check_rtc();
- write_sequnlock(&xtime_lock);
- if (adjusting_time && (time_adjust == 0))
- ppc_adjtimex();
- }
-
- next_dec = tb_ticks_per_jiffy - ticks;
- set_dec(next_dec);
+ if (evt->event_handler)
+ evt->event_handler(evt);
#ifdef CONFIG_PPC_ISERIES
- if (hvlpevent_is_pending())
- process_hvlpevents(regs);
+ if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending())
+ process_hvlpevents();
#endif
#ifdef CONFIG_PPC64
#endif
irq_exit();
+ set_irq_regs(old_regs);
}
void wakeup_decrementer(void)
{
- int i;
+ unsigned long ticks;
- set_dec(tb_ticks_per_jiffy);
/*
- * We don't expect this to be called on a machine with a 601,
- * so using get_tbl is fine.
+ * The timebase gets saved on sleep and restored on wakeup,
+ * so all we need to do is to reset the decrementer.
*/
- tb_last_stamp = tb_last_jiffy = get_tb();
- for_each_cpu(i)
- per_cpu(last_jiffy, i) = tb_last_stamp;
+ 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)
+{
+ preempt_disable();
+
+ /* Disable the decrementer, so that it doesn't interfere
+ * with suspending.
+ */
+
+ set_dec(0x7fffffff);
+ local_irq_disable();
+ set_dec(0x7fffffff);
+}
+
+void generic_suspend_enable_irqs(void)
+{
+ wakeup_decrementer();
+
+ local_irq_enable();
+ preempt_enable();
}
+/* Overrides the weak version in kernel/power/main.c */
+void arch_suspend_disable_irqs(void)
+{
+ if (ppc_md.suspend_disable_irqs)
+ ppc_md.suspend_disable_irqs();
+ generic_suspend_disable_irqs();
+}
+
+/* Overrides the weak version in kernel/power/main.c */
+void arch_suspend_enable_irqs(void)
+{
+ generic_suspend_enable_irqs();
+ if (ppc_md.suspend_enable_irqs)
+ ppc_md.suspend_enable_irqs();
+}
+#endif
+
#ifdef CONFIG_SMP
void __init smp_space_timers(unsigned int max_cpus)
{
int i;
- unsigned long offset = tb_ticks_per_jiffy / max_cpus;
- unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid);
+ u64 previous_tb = per_cpu(last_jiffy, boot_cpuid);
- for_each_cpu(i) {
- if (i != boot_cpuid) {
- previous_tb += offset;
- per_cpu(last_jiffy, i) = previous_tb;
- }
+ /* 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
{
if (__USE_RTC())
return get_rtc();
- return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
+ return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
}
-int do_settimeofday(struct timespec *tv)
+static int __init get_freq(char *name, int cells, unsigned long *val)
{
- time_t wtm_sec, new_sec = tv->tv_sec;
- long wtm_nsec, new_nsec = tv->tv_nsec;
- unsigned long flags;
- long int tb_delta;
- u64 new_xsec;
+ struct device_node *cpu;
+ const unsigned int *fp;
+ int found = 0;
- if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
- return -EINVAL;
+ /* The cpu node should have timebase and clock frequency properties */
+ cpu = of_find_node_by_type(NULL, "cpu");
- write_seqlock_irqsave(&xtime_lock, flags);
+ if (cpu) {
+ fp = of_get_property(cpu, name, NULL);
+ if (fp) {
+ found = 1;
+ *val = of_read_ulong(fp, cells);
+ }
- /*
- * Updating the RTC is not the job of this code. If the time is
- * stepped under NTP, the RTC will be updated after STA_UNSYNC
- * is cleared. Tools like clock/hwclock either copy the RTC
- * to the system time, in which case there is no point in writing
- * to the RTC again, or write to the RTC but then they don't call
- * settimeofday to perform this operation.
- */
-#ifdef CONFIG_PPC_ISERIES
- if (first_settimeofday) {
- iSeries_tb_recal();
- first_settimeofday = 0;
+ of_node_put(cpu);
}
-#endif
- tb_delta = tb_ticks_since(tb_last_stamp);
- tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy;
-
- new_nsec -= 1000 * mulhwu(tb_to_us, tb_delta);
-
- wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec);
- wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec);
-
- set_normalized_timespec(&xtime, new_sec, new_nsec);
- set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
- /* In case of a large backwards jump in time with NTP, we want the
- * clock to be updated as soon as the PLL is again in lock.
- */
- last_rtc_update = new_sec - 658;
-
- ntp_clear();
-
- new_xsec = (u64)new_nsec * XSEC_PER_SEC;
- do_div(new_xsec, NSEC_PER_SEC);
- new_xsec += (u64)new_sec * XSEC_PER_SEC;
- update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
-
-#ifdef CONFIG_PPC64
- systemcfg->tz_minuteswest = sys_tz.tz_minuteswest;
- systemcfg->tz_dsttime = sys_tz.tz_dsttime;
-#endif
-
- write_sequnlock_irqrestore(&xtime_lock, flags);
- clock_was_set();
- return 0;
+ return found;
}
-EXPORT_SYMBOL(do_settimeofday);
-
void __init generic_calibrate_decr(void)
{
- struct device_node *cpu;
- unsigned int *fp;
- int node_found;
+ ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
- /*
- * The cpu node should have a timebase-frequency property
- * to tell us the rate at which the decrementer counts.
- */
- cpu = of_find_node_by_type(NULL, "cpu");
+ if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
+ !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
- ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
- node_found = 0;
- if (cpu != 0) {
- fp = (unsigned int *)get_property(cpu, "timebase-frequency",
- NULL);
- if (fp != 0) {
- node_found = 1;
- ppc_tb_freq = *fp;
- }
- }
- if (!node_found)
printk(KERN_ERR "WARNING: Estimating decrementer frequency "
"(not found)\n");
+ }
- ppc_proc_freq = DEFAULT_PROC_FREQ;
- node_found = 0;
- if (cpu != 0) {
- fp = (unsigned int *)get_property(cpu, "clock-frequency",
- NULL);
- if (fp != 0) {
- node_found = 1;
- ppc_proc_freq = *fp;
- }
+ ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
+
+ if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
+ !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
+
+ printk(KERN_ERR "WARNING: Estimating processor frequency "
+ "(not found)\n");
}
-#ifdef CONFIG_BOOKE
+
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
/* Set the time base to zero */
mtspr(SPRN_TBWL, 0);
mtspr(SPRN_TBWU, 0);
/* Enable decrementer interrupt */
mtspr(SPRN_TCR, TCR_DIE);
#endif
- if (!node_found)
- printk(KERN_ERR "WARNING: Estimating processor frequency "
- "(not found)\n");
+}
+
+int update_persistent_clock(struct timespec now)
+{
+ struct rtc_time tm;
+
+ if (!ppc_md.set_rtc_time)
+ return 0;
+
+ to_tm(now.tv_sec + 1 + timezone_offset, &tm);
+ tm.tm_year -= 1900;
+ tm.tm_mon -= 1;
- of_node_put(cpu);
+ return ppc_md.set_rtc_time(&tm);
}
-unsigned long get_boot_time(void)
+unsigned long read_persistent_clock(void)
{
struct rtc_time tm;
+ static int first = 1;
+
+ /* XXX this is a litle fragile but will work okay in the short term */
+ if (first) {
+ first = 0;
+ if (ppc_md.time_init)
+ timezone_offset = ppc_md.time_init();
- if (ppc_md.get_boot_time)
- return ppc_md.get_boot_time();
+ /* get_boot_time() isn't guaranteed to be safe to call late */
+ if (ppc_md.get_boot_time)
+ return ppc_md.get_boot_time() -timezone_offset;
+ }
if (!ppc_md.get_rtc_time)
return 0;
ppc_md.get_rtc_time(&tm);
tm.tm_hour, tm.tm_min, tm.tm_sec);
}
+/* clocksource code */
+static cycle_t rtc_read(void)
+{
+ return (cycle_t)get_rtc();
+}
+
+static cycle_t timebase_read(void)
+{
+ return (cycle_t)get_tb();
+}
+
+void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
+{
+ u64 t2x, stamp_xsec;
+
+ if (clock != &clocksource_timebase)
+ return;
+
+ /* Make userspace gettimeofday spin until we're done. */
+ ++vdso_data->tb_update_count;
+ smp_mb();
+
+ /* XXX this assumes clock->shift == 22 */
+ /* 4611686018 ~= 2^(20+64-22) / 1e9 */
+ t2x = (u64) clock->mult * 4611686018ULL;
+ stamp_xsec = (u64) xtime.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);
+}
+
+void update_vsyscall_tz(void)
+{
+ /* Make userspace gettimeofday spin until we're done. */
+ ++vdso_data->tb_update_count;
+ smp_mb();
+ vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data->tz_dsttime = sys_tz.tz_dsttime;
+ smp_mb();
+ ++vdso_data->tb_update_count;
+}
+
+void __init clocksource_init(void)
+{
+ struct clocksource *clock;
+
+ if (__USE_RTC())
+ clock = &clocksource_rtc;
+ else
+ clock = &clocksource_timebase;
+
+ clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift);
+
+ if (clocksource_register(clock)) {
+ printk(KERN_ERR "clocksource: %s is already registered\n",
+ clock->name);
+ return;
+ }
+
+ printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
+ clock->name, clock->mult, clock->shift);
+}
+
+static int decrementer_set_next_event(unsigned long evt,
+ struct clock_event_device *dev)
+{
+ __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt;
+ set_dec(evt);
+ return 0;
+}
+
+static void decrementer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *dev)
+{
+ if (mode != CLOCK_EVT_MODE_ONESHOT)
+ decrementer_set_next_event(DECREMENTER_MAX, dev);
+}
+
+static void register_decrementer_clockevent(int cpu)
+{
+ struct clock_event_device *dec = &per_cpu(decrementers, cpu).event;
+
+ *dec = decrementer_clockevent;
+ dec->cpumask = cpumask_of_cpu(cpu);
+
+ printk(KERN_DEBUG "clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
+ dec->name, dec->mult, dec->shift, cpu);
+
+ clockevents_register_device(dec);
+}
+
+static void __init init_decrementer_clockevent(void)
+{
+ int cpu = smp_processor_id();
+
+ decrementer_clockevent.mult = div_sc(ppc_tb_freq, NSEC_PER_SEC,
+ decrementer_clockevent.shift);
+ decrementer_clockevent.max_delta_ns =
+ clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
+ decrementer_clockevent.min_delta_ns =
+ clockevent_delta2ns(2, &decrementer_clockevent);
+
+ register_decrementer_clockevent(cpu);
+}
+
+void secondary_cpu_time_init(void)
+{
+ /* FIME: Should make unrelatred change to move snapshot_timebase
+ * call here ! */
+ register_decrementer_clockevent(smp_processor_id());
+}
+
/* This function is only called on the boot processor */
void __init time_init(void)
{
unsigned long flags;
- unsigned long tm = 0;
struct div_result res;
- u64 scale;
+ u64 scale, x;
unsigned shift;
- if (ppc_md.time_init != NULL)
- timezone_offset = ppc_md.time_init();
-
if (__USE_RTC()) {
/* 601 processor: dec counts down by 128 every 128ns */
ppc_tb_freq = 1000000000;
- tb_last_stamp = get_rtcl();
- tb_last_jiffy = tb_last_stamp;
+ tb_last_jiffy = get_rtcl();
} else {
/* Normal PowerPC with timebase register */
ppc_md.calibrate_decr();
- printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
+ printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
- printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n",
+ printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
- tb_last_stamp = tb_last_jiffy = get_tb();
+ tb_last_jiffy = get_tb();
}
tb_ticks_per_jiffy = ppc_tb_freq / HZ;
- tb_ticks_per_sec = tb_ticks_per_jiffy * 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);
- div128_by_32(1024*1024, 0, tb_ticks_per_sec, &res);
- tb_to_xs = res.result_low;
+ calc_cputime_factors();
-#ifdef CONFIG_PPC64
- get_paca()->default_decr = tb_ticks_per_jiffy;
-#endif
+ /*
+ * 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.
}
tb_to_ns_scale = scale;
tb_to_ns_shift = shift;
-
-#ifdef CONFIG_PPC_ISERIES
- if (!piranha_simulator)
-#endif
- tm = get_boot_time();
+ /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
+ boot_tb = get_tb_or_rtc();
write_seqlock_irqsave(&xtime_lock, flags);
- xtime.tv_sec = tm;
- xtime.tv_nsec = 0;
+
+ /* 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;
+ }
+
do_gtod.varp = &do_gtod.vars[0];
do_gtod.var_idx = 0;
do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
- __get_cpu_var(last_jiffy) = tb_last_stamp;
+ __get_cpu_var(last_jiffy) = tb_last_jiffy;
do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
do_gtod.varp->tb_to_xs = tb_to_xs;
do_gtod.tb_to_us = tb_to_us;
-#ifdef CONFIG_PPC64
- systemcfg->tb_orig_stamp = tb_last_jiffy;
- systemcfg->tb_update_count = 0;
- systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
- systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
- systemcfg->tb_to_xs = tb_to_xs;
-#endif
- time_freq = 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;
- /* 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;
- xtime.tv_sec -= timezone_offset;
- }
-
- last_rtc_update = xtime.tv_sec;
- set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
write_sequnlock_irqrestore(&xtime_lock, flags);
- /* Not exact, but the timer interrupt takes care of this */
- set_dec(tb_ticks_per_jiffy);
-}
-
-/*
- * After adjtimex is called, adjust the conversion of tb ticks
- * to microseconds to keep do_gettimeofday synchronized
- * with ntpd.
- *
- * Use the time_adjust, time_freq and time_offset computed by adjtimex to
- * adjust the frequency.
- */
-
-/* #define DEBUG_PPC_ADJTIMEX 1 */
-
-void ppc_adjtimex(void)
-{
-#ifdef CONFIG_PPC64
- unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec,
- new_tb_to_xs, new_xsec, new_stamp_xsec;
- unsigned long tb_ticks_per_sec_delta;
- long delta_freq, ltemp;
- struct div_result divres;
- unsigned long flags;
- long singleshot_ppm = 0;
-
- /*
- * Compute parts per million frequency adjustment to
- * accomplish the time adjustment implied by time_offset to be
- * applied over the elapsed time indicated by time_constant.
- * Use SHIFT_USEC to get it into the same units as
- * time_freq.
- */
- if ( time_offset < 0 ) {
- ltemp = -time_offset;
- ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
- ltemp >>= SHIFT_KG + time_constant;
- ltemp = -ltemp;
- } else {
- ltemp = time_offset;
- ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
- ltemp >>= SHIFT_KG + time_constant;
- }
-
- /* If there is a single shot time adjustment in progress */
- if ( time_adjust ) {
-#ifdef DEBUG_PPC_ADJTIMEX
- printk("ppc_adjtimex: ");
- if ( adjusting_time == 0 )
- printk("starting ");
- printk("single shot time_adjust = %ld\n", time_adjust);
-#endif
-
- adjusting_time = 1;
-
- /*
- * Compute parts per million frequency adjustment
- * to match time_adjust
- */
- singleshot_ppm = tickadj * HZ;
- /*
- * The adjustment should be tickadj*HZ to match the code in
- * linux/kernel/timer.c, but experiments show that this is too
- * large. 3/4 of tickadj*HZ seems about right
- */
- singleshot_ppm -= singleshot_ppm / 4;
- /* Use SHIFT_USEC to get it into the same units as time_freq */
- singleshot_ppm <<= SHIFT_USEC;
- if ( time_adjust < 0 )
- singleshot_ppm = -singleshot_ppm;
- }
- else {
-#ifdef DEBUG_PPC_ADJTIMEX
- if ( adjusting_time )
- printk("ppc_adjtimex: ending single shot time_adjust\n");
-#endif
- adjusting_time = 0;
- }
-
- /* Add up all of the frequency adjustments */
- delta_freq = time_freq + ltemp + singleshot_ppm;
-
- /*
- * Compute a new value for tb_ticks_per_sec based on
- * the frequency adjustment
- */
- den = 1000000 * (1 << (SHIFT_USEC - 8));
- if ( delta_freq < 0 ) {
- tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den;
- new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta;
- }
- else {
- tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den;
- new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta;
- }
-
-#ifdef DEBUG_PPC_ADJTIMEX
- printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm);
- printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec);
-#endif
-
- /*
- * Compute a new value of tb_to_xs (used to convert tb to
- * microseconds) and a new value of stamp_xsec which is the
- * time (in 1/2^20 second units) corresponding to
- * tb_orig_stamp. This new value of stamp_xsec compensates
- * for the change in frequency (implied by the new tb_to_xs)
- * which guarantees that the current time remains the same.
- */
- write_seqlock_irqsave( &xtime_lock, flags );
- tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp;
- div128_by_32(1024*1024, 0, new_tb_ticks_per_sec, &divres);
- new_tb_to_xs = divres.result_low;
- new_xsec = mulhdu(tb_ticks, new_tb_to_xs);
-
- old_xsec = mulhdu(tb_ticks, do_gtod.varp->tb_to_xs);
- new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec;
-
- update_gtod(do_gtod.varp->tb_orig_stamp, new_stamp_xsec, new_tb_to_xs);
+ /* Register the clocksource, if we're not running on iSeries */
+ if (!firmware_has_feature(FW_FEATURE_ISERIES))
+ clocksource_init();
- write_sequnlock_irqrestore( &xtime_lock, flags );
-#endif /* CONFIG_PPC64 */
+ init_decrementer_clockevent();
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff