260a42309b
Change the current_tick_length() function so it takes an argument which specifies how much precision to return in shifted nanoseconds. This provides a simple way to convert between NTPs internal nanoseconds shifted by (SHIFT_SCALE - 10) to other shifted nanosecond units that are used by the clocksource abstraction. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1198 lines
33 KiB
C
1198 lines
33 KiB
C
/*
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* Common time routines among all ppc machines.
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*
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* Written by Cort Dougan (cort@cs.nmt.edu) to merge
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* Paul Mackerras' version and mine for PReP and Pmac.
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* MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
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* Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
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*
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* First round of bugfixes by Gabriel Paubert (paubert@iram.es)
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* to make clock more stable (2.4.0-test5). The only thing
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* that this code assumes is that the timebases have been synchronized
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* by firmware on SMP and are never stopped (never do sleep
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* on SMP then, nap and doze are OK).
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*
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* Speeded up do_gettimeofday by getting rid of references to
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* xtime (which required locks for consistency). (mikejc@us.ibm.com)
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*
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* TODO (not necessarily in this file):
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* - improve precision and reproducibility of timebase frequency
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* measurement at boot time. (for iSeries, we calibrate the timebase
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* against the Titan chip's clock.)
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* - for astronomical applications: add a new function to get
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* non ambiguous timestamps even around leap seconds. This needs
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* a new timestamp format and a good name.
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*
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* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <linux/timex.h>
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#include <linux/kernel_stat.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/profile.h>
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#include <linux/cpu.h>
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#include <linux/security.h>
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#include <linux/percpu.h>
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#include <linux/rtc.h>
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#include <linux/jiffies.h>
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#include <linux/posix-timers.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/nvram.h>
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#include <asm/cache.h>
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#include <asm/machdep.h>
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#include <asm/uaccess.h>
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#include <asm/time.h>
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#include <asm/prom.h>
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#include <asm/irq.h>
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#include <asm/div64.h>
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#include <asm/smp.h>
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#include <asm/vdso_datapage.h>
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#ifdef CONFIG_PPC64
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#include <asm/firmware.h>
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#endif
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#ifdef CONFIG_PPC_ISERIES
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#include <asm/iseries/it_lp_queue.h>
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#include <asm/iseries/hv_call_xm.h>
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#endif
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#include <asm/smp.h>
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/* keep track of when we need to update the rtc */
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time_t last_rtc_update;
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#ifdef CONFIG_PPC_ISERIES
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unsigned long iSeries_recal_titan = 0;
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unsigned long iSeries_recal_tb = 0;
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static unsigned long first_settimeofday = 1;
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#endif
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/* The decrementer counts down by 128 every 128ns on a 601. */
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#define DECREMENTER_COUNT_601 (1000000000 / HZ)
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#define XSEC_PER_SEC (1024*1024)
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#ifdef CONFIG_PPC64
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#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
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#else
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/* compute ((xsec << 12) * max) >> 32 */
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#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
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#endif
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unsigned long tb_ticks_per_jiffy;
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unsigned long tb_ticks_per_usec = 100; /* sane default */
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EXPORT_SYMBOL(tb_ticks_per_usec);
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unsigned long tb_ticks_per_sec;
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EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
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u64 tb_to_xs;
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unsigned tb_to_us;
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#define TICKLEN_SCALE (SHIFT_SCALE - 10)
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u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
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u64 ticklen_to_xs; /* 0.64 fraction */
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/* If last_tick_len corresponds to about 1/HZ seconds, then
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last_tick_len << TICKLEN_SHIFT will be about 2^63. */
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#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL_GPL(rtc_lock);
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u64 tb_to_ns_scale;
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unsigned tb_to_ns_shift;
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struct gettimeofday_struct do_gtod;
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extern unsigned long wall_jiffies;
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extern struct timezone sys_tz;
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static long timezone_offset;
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unsigned long ppc_proc_freq;
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unsigned long ppc_tb_freq;
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u64 tb_last_jiffy __cacheline_aligned_in_smp;
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unsigned long tb_last_stamp;
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/*
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* Note that on ppc32 this only stores the bottom 32 bits of
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* the timebase value, but that's enough to tell when a jiffy
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* has passed.
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*/
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DEFINE_PER_CPU(unsigned long, last_jiffy);
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING
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/*
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* Factors for converting from cputime_t (timebase ticks) to
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* jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
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* These are all stored as 0.64 fixed-point binary fractions.
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*/
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u64 __cputime_jiffies_factor;
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EXPORT_SYMBOL(__cputime_jiffies_factor);
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u64 __cputime_msec_factor;
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EXPORT_SYMBOL(__cputime_msec_factor);
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u64 __cputime_sec_factor;
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EXPORT_SYMBOL(__cputime_sec_factor);
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u64 __cputime_clockt_factor;
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EXPORT_SYMBOL(__cputime_clockt_factor);
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static void calc_cputime_factors(void)
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{
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struct div_result res;
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div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
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__cputime_jiffies_factor = res.result_low;
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div128_by_32(1000, 0, tb_ticks_per_sec, &res);
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__cputime_msec_factor = res.result_low;
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div128_by_32(1, 0, tb_ticks_per_sec, &res);
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__cputime_sec_factor = res.result_low;
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div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
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__cputime_clockt_factor = res.result_low;
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}
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/*
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* Read the PURR on systems that have it, otherwise the timebase.
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*/
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static u64 read_purr(void)
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{
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if (cpu_has_feature(CPU_FTR_PURR))
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return mfspr(SPRN_PURR);
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return mftb();
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}
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/*
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* Account time for a transition between system, hard irq
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* or soft irq state.
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*/
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void account_system_vtime(struct task_struct *tsk)
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{
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u64 now, delta;
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unsigned long flags;
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local_irq_save(flags);
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now = read_purr();
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delta = now - get_paca()->startpurr;
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get_paca()->startpurr = now;
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if (!in_interrupt()) {
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delta += get_paca()->system_time;
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get_paca()->system_time = 0;
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}
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account_system_time(tsk, 0, delta);
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local_irq_restore(flags);
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}
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/*
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* Transfer the user and system times accumulated in the paca
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* by the exception entry and exit code to the generic process
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* user and system time records.
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* Must be called with interrupts disabled.
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*/
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void account_process_vtime(struct task_struct *tsk)
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{
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cputime_t utime;
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utime = get_paca()->user_time;
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get_paca()->user_time = 0;
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account_user_time(tsk, utime);
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}
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static void account_process_time(struct pt_regs *regs)
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{
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int cpu = smp_processor_id();
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account_process_vtime(current);
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run_local_timers();
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if (rcu_pending(cpu))
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rcu_check_callbacks(cpu, user_mode(regs));
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scheduler_tick();
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run_posix_cpu_timers(current);
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}
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#ifdef CONFIG_PPC_SPLPAR
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/*
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* Stuff for accounting stolen time.
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*/
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struct cpu_purr_data {
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int initialized; /* thread is running */
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u64 tb0; /* timebase at origin time */
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u64 purr0; /* PURR at origin time */
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u64 tb; /* last TB value read */
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u64 purr; /* last PURR value read */
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u64 stolen; /* stolen time so far */
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spinlock_t lock;
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};
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static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data);
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static void snapshot_tb_and_purr(void *data)
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{
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struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data);
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p->tb0 = mftb();
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p->purr0 = mfspr(SPRN_PURR);
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p->tb = p->tb0;
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p->purr = 0;
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wmb();
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p->initialized = 1;
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}
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/*
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* Called during boot when all cpus have come up.
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*/
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void snapshot_timebases(void)
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{
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int cpu;
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if (!cpu_has_feature(CPU_FTR_PURR))
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return;
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for_each_possible_cpu(cpu)
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spin_lock_init(&per_cpu(cpu_purr_data, cpu).lock);
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on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1);
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}
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void calculate_steal_time(void)
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{
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u64 tb, purr, t0;
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s64 stolen;
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struct cpu_purr_data *p0, *pme, *phim;
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int cpu;
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if (!cpu_has_feature(CPU_FTR_PURR))
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return;
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cpu = smp_processor_id();
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pme = &per_cpu(cpu_purr_data, cpu);
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if (!pme->initialized)
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return; /* this can happen in early boot */
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p0 = &per_cpu(cpu_purr_data, cpu & ~1);
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phim = &per_cpu(cpu_purr_data, cpu ^ 1);
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spin_lock(&p0->lock);
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tb = mftb();
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purr = mfspr(SPRN_PURR) - pme->purr0;
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if (!phim->initialized || !cpu_online(cpu ^ 1)) {
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stolen = (tb - pme->tb) - (purr - pme->purr);
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} else {
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t0 = pme->tb0;
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if (phim->tb0 < t0)
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t0 = phim->tb0;
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stolen = phim->tb - t0 - phim->purr - purr - p0->stolen;
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}
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if (stolen > 0) {
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account_steal_time(current, stolen);
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p0->stolen += stolen;
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}
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pme->tb = tb;
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pme->purr = purr;
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spin_unlock(&p0->lock);
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}
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/*
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* Must be called before the cpu is added to the online map when
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* a cpu is being brought up at runtime.
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*/
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static void snapshot_purr(void)
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{
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int cpu;
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u64 purr;
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struct cpu_purr_data *p0, *pme, *phim;
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unsigned long flags;
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if (!cpu_has_feature(CPU_FTR_PURR))
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return;
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cpu = smp_processor_id();
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pme = &per_cpu(cpu_purr_data, cpu);
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p0 = &per_cpu(cpu_purr_data, cpu & ~1);
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phim = &per_cpu(cpu_purr_data, cpu ^ 1);
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spin_lock_irqsave(&p0->lock, flags);
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pme->tb = pme->tb0 = mftb();
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purr = mfspr(SPRN_PURR);
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if (!phim->initialized) {
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pme->purr = 0;
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pme->purr0 = purr;
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} else {
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/* set p->purr and p->purr0 for no change in p0->stolen */
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pme->purr = phim->tb - phim->tb0 - phim->purr - p0->stolen;
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pme->purr0 = purr - pme->purr;
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}
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pme->initialized = 1;
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spin_unlock_irqrestore(&p0->lock, flags);
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}
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#endif /* CONFIG_PPC_SPLPAR */
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#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
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#define calc_cputime_factors()
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#define account_process_time(regs) update_process_times(user_mode(regs))
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#define calculate_steal_time() do { } while (0)
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#endif
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#if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
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#define snapshot_purr() do { } while (0)
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#endif
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/*
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* Called when a cpu comes up after the system has finished booting,
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* i.e. as a result of a hotplug cpu action.
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*/
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void snapshot_timebase(void)
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{
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__get_cpu_var(last_jiffy) = get_tb();
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snapshot_purr();
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}
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void __delay(unsigned long loops)
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{
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unsigned long start;
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int diff;
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if (__USE_RTC()) {
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start = get_rtcl();
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do {
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/* the RTCL register wraps at 1000000000 */
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diff = get_rtcl() - start;
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if (diff < 0)
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diff += 1000000000;
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} while (diff < loops);
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} else {
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start = get_tbl();
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while (get_tbl() - start < loops)
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HMT_low();
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HMT_medium();
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}
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}
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EXPORT_SYMBOL(__delay);
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void udelay(unsigned long usecs)
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{
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__delay(tb_ticks_per_usec * usecs);
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}
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EXPORT_SYMBOL(udelay);
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static __inline__ void timer_check_rtc(void)
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{
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/*
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* update the rtc when needed, this should be performed on the
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* right fraction of a second. Half or full second ?
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* Full second works on mk48t59 clocks, others need testing.
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* Note that this update is basically only used through
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* the adjtimex system calls. Setting the HW clock in
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* any other way is a /dev/rtc and userland business.
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* This is still wrong by -0.5/+1.5 jiffies because of the
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* timer interrupt resolution and possible delay, but here we
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* hit a quantization limit which can only be solved by higher
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* resolution timers and decoupling time management from timer
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* interrupts. This is also wrong on the clocks
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* which require being written at the half second boundary.
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* We should have an rtc call that only sets the minutes and
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* seconds like on Intel to avoid problems with non UTC clocks.
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*/
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if (ppc_md.set_rtc_time && ntp_synced() &&
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xtime.tv_sec - last_rtc_update >= 659 &&
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abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) {
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struct rtc_time tm;
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to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
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tm.tm_year -= 1900;
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tm.tm_mon -= 1;
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if (ppc_md.set_rtc_time(&tm) == 0)
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last_rtc_update = xtime.tv_sec + 1;
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else
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/* Try again one minute later */
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last_rtc_update += 60;
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}
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}
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|
|
/*
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* This version of gettimeofday has microsecond resolution.
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|
*/
|
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static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val)
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{
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unsigned long sec, usec;
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u64 tb_ticks, xsec;
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struct gettimeofday_vars *temp_varp;
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u64 temp_tb_to_xs, temp_stamp_xsec;
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|
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/*
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* These calculations are faster (gets rid of divides)
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* if done in units of 1/2^20 rather than microseconds.
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* The conversion to microseconds at the end is done
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* without a divide (and in fact, without a multiply)
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*/
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temp_varp = do_gtod.varp;
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tb_ticks = tb_val - temp_varp->tb_orig_stamp;
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temp_tb_to_xs = temp_varp->tb_to_xs;
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temp_stamp_xsec = temp_varp->stamp_xsec;
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xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs);
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sec = xsec / XSEC_PER_SEC;
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usec = (unsigned long)xsec & (XSEC_PER_SEC - 1);
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usec = SCALE_XSEC(usec, 1000000);
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tv->tv_sec = sec;
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tv->tv_usec = usec;
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}
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|
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void do_gettimeofday(struct timeval *tv)
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|
{
|
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if (__USE_RTC()) {
|
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/* do this the old way */
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unsigned long flags, seq;
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unsigned int sec, nsec, usec;
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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sec = xtime.tv_sec;
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nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp);
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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usec = nsec / 1000;
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while (usec >= 1000000) {
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usec -= 1000000;
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++sec;
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}
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tv->tv_sec = sec;
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tv->tv_usec = usec;
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return;
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}
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__do_gettimeofday(tv, get_tb());
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}
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|
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EXPORT_SYMBOL(do_gettimeofday);
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|
|
/*
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* There are two copies of tb_to_xs and stamp_xsec so that no
|
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* lock is needed to access and use these values in
|
|
* do_gettimeofday. We alternate the copies and as long as a
|
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* reasonable time elapses between changes, there will never
|
|
* be inconsistent values. ntpd has a minimum of one minute
|
|
* between updates.
|
|
*/
|
|
static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
|
|
u64 new_tb_to_xs)
|
|
{
|
|
unsigned temp_idx;
|
|
struct gettimeofday_vars *temp_varp;
|
|
|
|
temp_idx = (do_gtod.var_idx == 0);
|
|
temp_varp = &do_gtod.vars[temp_idx];
|
|
|
|
temp_varp->tb_to_xs = new_tb_to_xs;
|
|
temp_varp->tb_orig_stamp = new_tb_stamp;
|
|
temp_varp->stamp_xsec = new_stamp_xsec;
|
|
smp_mb();
|
|
do_gtod.varp = temp_varp;
|
|
do_gtod.var_idx = temp_idx;
|
|
|
|
/*
|
|
* 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;
|
|
smp_wmb();
|
|
++(vdso_data->tb_update_count);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
u64 tlen, t2x;
|
|
u64 tb, xsec_old, xsec_new;
|
|
struct gettimeofday_vars *varp;
|
|
|
|
if (__USE_RTC())
|
|
return;
|
|
tlen = current_tick_length(SHIFT_SCALE - 10);
|
|
offset = cur_tb - do_gtod.varp->tb_orig_stamp;
|
|
if (tlen == last_tick_len && offset < 0x80000000u)
|
|
return;
|
|
if (tlen != last_tick_len) {
|
|
t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs);
|
|
last_tick_len = tlen;
|
|
} else
|
|
t2x = do_gtod.varp->tb_to_xs;
|
|
new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
|
|
do_div(new_stamp_xsec, 1000000000);
|
|
new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
|
|
|
|
++vdso_data->tb_update_count;
|
|
smp_mb();
|
|
|
|
/*
|
|
* Make sure time doesn't go backwards for userspace gettimeofday.
|
|
*/
|
|
tb = get_tb();
|
|
varp = do_gtod.varp;
|
|
xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs)
|
|
+ varp->stamp_xsec;
|
|
xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec;
|
|
if (xsec_new < xsec_old)
|
|
new_stamp_xsec += xsec_old - xsec_new;
|
|
|
|
update_gtod(cur_tb, new_stamp_xsec, t2x);
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
unsigned long profile_pc(struct pt_regs *regs)
|
|
{
|
|
unsigned long pc = instruction_pointer(regs);
|
|
|
|
if (in_lock_functions(pc))
|
|
return regs->link;
|
|
|
|
return pc;
|
|
}
|
|
EXPORT_SYMBOL(profile_pc);
|
|
#endif
|
|
|
|
#ifdef CONFIG_PPC_ISERIES
|
|
|
|
/*
|
|
* This function recalibrates the timebase based on the 49-bit time-of-day
|
|
* value in the Titan chip. The Titan is much more accurate than the value
|
|
* returned by the service processor for the timebase frequency.
|
|
*/
|
|
|
|
static void iSeries_tb_recal(void)
|
|
{
|
|
struct div_result divres;
|
|
unsigned long titan, tb;
|
|
tb = get_tb();
|
|
titan = HvCallXm_loadTod();
|
|
if ( iSeries_recal_titan ) {
|
|
unsigned long tb_ticks = tb - iSeries_recal_tb;
|
|
unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12;
|
|
unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec;
|
|
unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ;
|
|
long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy;
|
|
char sign = '+';
|
|
/* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
|
|
new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ;
|
|
|
|
if ( tick_diff < 0 ) {
|
|
tick_diff = -tick_diff;
|
|
sign = '-';
|
|
}
|
|
if ( tick_diff ) {
|
|
if ( tick_diff < tb_ticks_per_jiffy/25 ) {
|
|
printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
|
|
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;
|
|
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"
|
|
" new tb_ticks_per_jiffy = %lu\n"
|
|
" old tb_ticks_per_jiffy = %lu\n",
|
|
new_tb_ticks_per_jiffy, tb_ticks_per_jiffy );
|
|
}
|
|
}
|
|
}
|
|
iSeries_recal_titan = titan;
|
|
iSeries_recal_tb = tb;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* For iSeries shared processors, we have to let the hypervisor
|
|
* set the hardware decrementer. We set a virtual decrementer
|
|
* in the lppaca and call the hypervisor if the virtual
|
|
* decrementer is less than the current value in the hardware
|
|
* decrementer. (almost always the new decrementer value will
|
|
* be greater than the current hardware decementer so the hypervisor
|
|
* call will not be needed)
|
|
*/
|
|
|
|
/*
|
|
* timer_interrupt - gets called when the decrementer overflows,
|
|
* with interrupts disabled.
|
|
*/
|
|
void timer_interrupt(struct pt_regs * regs)
|
|
{
|
|
int next_dec;
|
|
int cpu = smp_processor_id();
|
|
unsigned long ticks;
|
|
|
|
#ifdef CONFIG_PPC32
|
|
if (atomic_read(&ppc_n_lost_interrupts) != 0)
|
|
do_IRQ(regs);
|
|
#endif
|
|
|
|
irq_enter();
|
|
|
|
profile_tick(CPU_PROFILING, regs);
|
|
calculate_steal_time();
|
|
|
|
#ifdef CONFIG_PPC_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))
|
|
account_process_time(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);
|
|
do_timer(regs);
|
|
timer_recalc_offset(tb_last_jiffy);
|
|
timer_check_rtc();
|
|
write_sequnlock(&xtime_lock);
|
|
}
|
|
|
|
next_dec = tb_ticks_per_jiffy - ticks;
|
|
set_dec(next_dec);
|
|
|
|
#ifdef CONFIG_PPC_ISERIES
|
|
if (hvlpevent_is_pending())
|
|
process_hvlpevents(regs);
|
|
#endif
|
|
|
|
#ifdef CONFIG_PPC64
|
|
/* collect purr register values often, for accurate calculations */
|
|
if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
|
|
struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
|
|
cu->current_tb = mfspr(SPRN_PURR);
|
|
}
|
|
#endif
|
|
|
|
irq_exit();
|
|
}
|
|
|
|
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_SMP
|
|
void __init smp_space_timers(unsigned int max_cpus)
|
|
{
|
|
int i;
|
|
unsigned long half = tb_ticks_per_jiffy / 2;
|
|
unsigned long offset = tb_ticks_per_jiffy / max_cpus;
|
|
unsigned long 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;
|
|
/*
|
|
* The stolen time calculation for POWER5 shared-processor LPAR
|
|
* systems works better if the two threads' timebase interrupts
|
|
* are staggered by half a jiffy with respect to each other.
|
|
*/
|
|
for_each_possible_cpu(i) {
|
|
if (i == boot_cpuid)
|
|
continue;
|
|
if (i == (boot_cpuid ^ 1))
|
|
per_cpu(last_jiffy, i) =
|
|
per_cpu(last_jiffy, boot_cpuid) - half;
|
|
else if (i & 1)
|
|
per_cpu(last_jiffy, i) =
|
|
per_cpu(last_jiffy, i ^ 1) + half;
|
|
else {
|
|
previous_tb += offset;
|
|
per_cpu(last_jiffy, i) = previous_tb;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Scheduler clock - returns current time in nanosec units.
|
|
*
|
|
* Note: mulhdu(a, b) (multiply high double unsigned) returns
|
|
* the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
|
|
* are 64-bit unsigned numbers.
|
|
*/
|
|
unsigned long long sched_clock(void)
|
|
{
|
|
if (__USE_RTC())
|
|
return get_rtc();
|
|
return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
|
|
}
|
|
|
|
int do_settimeofday(struct timespec *tv)
|
|
{
|
|
time_t wtm_sec, new_sec = tv->tv_sec;
|
|
long wtm_nsec, new_nsec = tv->tv_nsec;
|
|
unsigned long flags;
|
|
u64 new_xsec;
|
|
unsigned long tb_delta;
|
|
|
|
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
|
|
return -EINVAL;
|
|
|
|
write_seqlock_irqsave(&xtime_lock, flags);
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
#endif
|
|
|
|
/* Make userspace gettimeofday spin until we're done. */
|
|
++vdso_data->tb_update_count;
|
|
smp_mb();
|
|
|
|
/*
|
|
* Subtract off the number of nanoseconds since the
|
|
* beginning of the last tick.
|
|
* Note that since we don't increment jiffies_64 anywhere other
|
|
* than in do_timer (since we don't have a lost tick problem),
|
|
* wall_jiffies will always be the same as jiffies,
|
|
* and therefore the (jiffies - wall_jiffies) computation
|
|
* has been removed.
|
|
*/
|
|
tb_delta = tb_ticks_since(tb_last_stamp);
|
|
tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */
|
|
new_nsec -= SCALE_XSEC(tb_delta, 1000000000);
|
|
|
|
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 = xtime.tv_nsec;
|
|
if (new_xsec != 0) {
|
|
new_xsec *= XSEC_PER_SEC;
|
|
do_div(new_xsec, NSEC_PER_SEC);
|
|
}
|
|
new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC;
|
|
update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
|
|
|
|
vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
|
|
vdso_data->tz_dsttime = sys_tz.tz_dsttime;
|
|
|
|
write_sequnlock_irqrestore(&xtime_lock, flags);
|
|
clock_was_set();
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(do_settimeofday);
|
|
|
|
static int __init get_freq(char *name, int cells, unsigned long *val)
|
|
{
|
|
struct device_node *cpu;
|
|
unsigned int *fp;
|
|
int found = 0;
|
|
|
|
/* The cpu node should have timebase and clock frequency properties */
|
|
cpu = of_find_node_by_type(NULL, "cpu");
|
|
|
|
if (cpu) {
|
|
fp = (unsigned int *)get_property(cpu, name, NULL);
|
|
if (fp) {
|
|
found = 1;
|
|
*val = 0;
|
|
while (cells--)
|
|
*val = (*val << 32) | *fp++;
|
|
}
|
|
|
|
of_node_put(cpu);
|
|
}
|
|
|
|
return found;
|
|
}
|
|
|
|
void __init generic_calibrate_decr(void)
|
|
{
|
|
ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
|
|
|
|
if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
|
|
!get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
|
|
|
|
printk(KERN_ERR "WARNING: Estimating decrementer frequency "
|
|
"(not found)\n");
|
|
}
|
|
|
|
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
|
|
/* Set the time base to zero */
|
|
mtspr(SPRN_TBWL, 0);
|
|
mtspr(SPRN_TBWU, 0);
|
|
|
|
/* Clear any pending timer interrupts */
|
|
mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
|
|
|
|
/* Enable decrementer interrupt */
|
|
mtspr(SPRN_TCR, TCR_DIE);
|
|
#endif
|
|
}
|
|
|
|
unsigned long get_boot_time(void)
|
|
{
|
|
struct rtc_time tm;
|
|
|
|
if (ppc_md.get_boot_time)
|
|
return ppc_md.get_boot_time();
|
|
if (!ppc_md.get_rtc_time)
|
|
return 0;
|
|
ppc_md.get_rtc_time(&tm);
|
|
return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
|
|
tm.tm_hour, tm.tm_min, tm.tm_sec);
|
|
}
|
|
|
|
/* 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, 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;
|
|
} else {
|
|
/* Normal PowerPC with timebase register */
|
|
ppc_md.calibrate_decr();
|
|
printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
|
|
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_stamp = 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();
|
|
|
|
/*
|
|
* 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.
|
|
* We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
|
|
* the 128-bit result as a 64.64 fixed-point number.
|
|
* We then shift that number right until it is less than 1.0,
|
|
* giving us the scale factor and shift count to use in
|
|
* sched_clock().
|
|
*/
|
|
div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
|
|
scale = res.result_low;
|
|
for (shift = 0; res.result_high != 0; ++shift) {
|
|
scale = (scale >> 1) | (res.result_high << 63);
|
|
res.result_high >>= 1;
|
|
}
|
|
tb_to_ns_scale = scale;
|
|
tb_to_ns_shift = shift;
|
|
|
|
tm = get_boot_time();
|
|
|
|
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;
|
|
tm -= timezone_offset;
|
|
}
|
|
|
|
xtime.tv_sec = tm;
|
|
xtime.tv_nsec = 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;
|
|
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;
|
|
|
|
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;
|
|
|
|
time_freq = 0;
|
|
|
|
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);
|
|
}
|
|
|
|
|
|
#define FEBRUARY 2
|
|
#define STARTOFTIME 1970
|
|
#define SECDAY 86400L
|
|
#define SECYR (SECDAY * 365)
|
|
#define leapyear(year) ((year) % 4 == 0 && \
|
|
((year) % 100 != 0 || (year) % 400 == 0))
|
|
#define days_in_year(a) (leapyear(a) ? 366 : 365)
|
|
#define days_in_month(a) (month_days[(a) - 1])
|
|
|
|
static int month_days[12] = {
|
|
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
|
|
};
|
|
|
|
/*
|
|
* This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
|
|
*/
|
|
void GregorianDay(struct rtc_time * tm)
|
|
{
|
|
int leapsToDate;
|
|
int lastYear;
|
|
int day;
|
|
int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
|
|
|
|
lastYear = tm->tm_year - 1;
|
|
|
|
/*
|
|
* Number of leap corrections to apply up to end of last year
|
|
*/
|
|
leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
|
|
|
|
/*
|
|
* This year is a leap year if it is divisible by 4 except when it is
|
|
* divisible by 100 unless it is divisible by 400
|
|
*
|
|
* e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
|
|
*/
|
|
day = tm->tm_mon > 2 && leapyear(tm->tm_year);
|
|
|
|
day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
|
|
tm->tm_mday;
|
|
|
|
tm->tm_wday = day % 7;
|
|
}
|
|
|
|
void to_tm(int tim, struct rtc_time * tm)
|
|
{
|
|
register int i;
|
|
register long hms, day;
|
|
|
|
day = tim / SECDAY;
|
|
hms = tim % SECDAY;
|
|
|
|
/* Hours, minutes, seconds are easy */
|
|
tm->tm_hour = hms / 3600;
|
|
tm->tm_min = (hms % 3600) / 60;
|
|
tm->tm_sec = (hms % 3600) % 60;
|
|
|
|
/* Number of years in days */
|
|
for (i = STARTOFTIME; day >= days_in_year(i); i++)
|
|
day -= days_in_year(i);
|
|
tm->tm_year = i;
|
|
|
|
/* Number of months in days left */
|
|
if (leapyear(tm->tm_year))
|
|
days_in_month(FEBRUARY) = 29;
|
|
for (i = 1; day >= days_in_month(i); i++)
|
|
day -= days_in_month(i);
|
|
days_in_month(FEBRUARY) = 28;
|
|
tm->tm_mon = i;
|
|
|
|
/* Days are what is left over (+1) from all that. */
|
|
tm->tm_mday = day + 1;
|
|
|
|
/*
|
|
* Determine the day of week
|
|
*/
|
|
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.
|
|
*/
|
|
void div128_by_32(u64 dividend_high, u64 dividend_low,
|
|
unsigned divisor, struct div_result *dr)
|
|
{
|
|
unsigned long a, b, c, d;
|
|
unsigned long w, x, y, z;
|
|
u64 ra, rb, rc;
|
|
|
|
a = dividend_high >> 32;
|
|
b = dividend_high & 0xffffffff;
|
|
c = dividend_low >> 32;
|
|
d = dividend_low & 0xffffffff;
|
|
|
|
w = a / divisor;
|
|
ra = ((u64)(a - (w * divisor)) << 32) + b;
|
|
|
|
rb = ((u64) do_div(ra, divisor) << 32) + c;
|
|
x = ra;
|
|
|
|
rc = ((u64) do_div(rb, divisor) << 32) + d;
|
|
y = rb;
|
|
|
|
do_div(rc, divisor);
|
|
z = rc;
|
|
|
|
dr->result_high = ((u64)w << 32) + x;
|
|
dr->result_low = ((u64)y << 32) + z;
|
|
|
|
}
|