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Merge branch 'powerpc.cherry-picks' into timers/clocksource
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Conflicts:
	arch/powerpc/kernel/time.c

Reason: The powerpc next tree contains two commits which conflict with
the timekeeping changes:

8fd63a9 powerpc: Rework VDSO gettimeofday to prevent time going backwards
c1aa687 powerpc: Clean up obsolete code relating to decrementer and timebase

John Stultz identified them and provided the conflict resolution.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Thomas Gleixner committed Jul 28, 2010
2 parents 852db46 + d75d68c commit 47916be
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Showing 11 changed files with 80 additions and 363 deletions.
3 changes: 0 additions & 3 deletions arch/powerpc/include/asm/machdep.h
View file
Expand Up @@ -366,8 +366,5 @@ static inline void log_error(char *buf, unsigned int err_type, int fatal)
#define machine_late_initcall(mach,fn) __define_machine_initcall(mach,"7",fn,7)
#define machine_late_initcall_sync(mach,fn) __define_machine_initcall(mach,"7s",fn,7s)

void generic_suspend_disable_irqs(void);
void generic_suspend_enable_irqs(void);

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_MACHDEP_H */
7 changes: 0 additions & 7 deletions arch/powerpc/include/asm/time.h
View file
Expand Up @@ -28,16 +28,12 @@
extern unsigned long tb_ticks_per_jiffy;
extern unsigned long tb_ticks_per_usec;
extern unsigned long tb_ticks_per_sec;
extern u64 tb_to_xs;
extern unsigned tb_to_us;

struct rtc_time;
extern void to_tm(int tim, struct rtc_time * tm);
extern void GregorianDay(struct rtc_time *tm);
extern time_t last_rtc_update;

extern void generic_calibrate_decr(void);
extern void wakeup_decrementer(void);
extern void snapshot_timebase(void);

extern void set_dec_cpu6(unsigned int val);
Expand Down Expand Up @@ -204,9 +200,6 @@ static inline unsigned long tb_ticks_since(unsigned long tstamp)
extern u64 mulhdu(u64, u64);
#endif

extern void smp_space_timers(unsigned int);

extern unsigned mulhwu_scale_factor(unsigned, unsigned);
extern void div128_by_32(u64 dividend_high, u64 dividend_low,
unsigned divisor, struct div_result *dr);

Expand Down
2 changes: 2 additions & 0 deletions arch/powerpc/include/asm/vdso_datapage.h
View file
Expand Up @@ -85,6 +85,7 @@ struct vdso_data {
__s32 wtom_clock_sec; /* Wall to monotonic clock */
__s32 wtom_clock_nsec;
struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
__u32 stamp_sec_fraction; /* fractional seconds of stamp_xtime */
__u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls */
__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
};
Expand All @@ -105,6 +106,7 @@ struct vdso_data {
__s32 wtom_clock_sec; /* Wall to monotonic clock */
__s32 wtom_clock_nsec;
struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
__u32 stamp_sec_fraction; /* fractional seconds of stamp_xtime */
__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
__u32 dcache_block_size; /* L1 d-cache block size */
__u32 icache_block_size; /* L1 i-cache block size */
Expand Down
1 change: 1 addition & 0 deletions arch/powerpc/kernel/asm-offsets.c
View file
Expand Up @@ -342,6 +342,7 @@ int main(void)
DEFINE(WTOM_CLOCK_SEC, offsetof(struct vdso_data, wtom_clock_sec));
DEFINE(WTOM_CLOCK_NSEC, offsetof(struct vdso_data, wtom_clock_nsec));
DEFINE(STAMP_XTIME, offsetof(struct vdso_data, stamp_xtime));
DEFINE(STAMP_SEC_FRAC, offsetof(struct vdso_data, stamp_sec_fraction));
DEFINE(CFG_ICACHE_BLOCKSZ, offsetof(struct vdso_data, icache_block_size));
DEFINE(CFG_DCACHE_BLOCKSZ, offsetof(struct vdso_data, dcache_block_size));
DEFINE(CFG_ICACHE_LOGBLOCKSZ, offsetof(struct vdso_data, icache_log_block_size));
Expand Down
2 changes: 0 additions & 2 deletions arch/powerpc/kernel/smp.c
View file
Expand Up @@ -288,8 +288,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
max_cpus = NR_CPUS;
else
max_cpus = 1;

smp_space_timers(max_cpus);

for_each_possible_cpu(cpu)
if (cpu != boot_cpuid)
Expand Down
142 changes: 9 additions & 133 deletions arch/powerpc/kernel/time.c
View file
Expand Up @@ -149,16 +149,6 @@ unsigned long tb_ticks_per_usec = 100; /* sane default */
EXPORT_SYMBOL(tb_ticks_per_usec);
unsigned long tb_ticks_per_sec;
EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
u64 tb_to_xs;
unsigned tb_to_us;

#define TICKLEN_SCALE NTP_SCALE_SHIFT
static u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
static u64 ticklen_to_xs; /* 0.64 fraction */

/* If last_tick_len corresponds to about 1/HZ seconds, then
last_tick_len << TICKLEN_SHIFT will be about 2^63. */
#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)

DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL_GPL(rtc_lock);
Expand All @@ -174,7 +164,6 @@ unsigned long ppc_proc_freq;
EXPORT_SYMBOL(ppc_proc_freq);
unsigned long ppc_tb_freq;

static u64 tb_last_jiffy __cacheline_aligned_in_smp;
static DEFINE_PER_CPU(u64, last_jiffy);

#ifdef CONFIG_VIRT_CPU_ACCOUNTING
Expand Down Expand Up @@ -446,7 +435,6 @@ EXPORT_SYMBOL(profile_pc);

static int __init iSeries_tb_recal(void)
{
struct div_result divres;
unsigned long titan, tb;

/* Make sure we only run on iSeries */
Expand Down Expand Up @@ -477,10 +465,7 @@ static int __init iSeries_tb_recal(void)
tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
tb_ticks_per_sec = new_tb_ticks_per_sec;
calc_cputime_factors();
div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
tb_to_xs = divres.result_low;
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
vdso_data->tb_to_xs = tb_to_xs;
setup_cputime_one_jiffy();
}
else {
Expand Down Expand Up @@ -643,27 +628,9 @@ void timer_interrupt(struct pt_regs * regs)
trace_timer_interrupt_exit(regs);
}

void wakeup_decrementer(void)
{
unsigned long ticks;

/*
* The timebase gets saved on sleep and restored on wakeup,
* so all we need to do is to reset the decrementer.
*/
ticks = tb_ticks_since(__get_cpu_var(last_jiffy));
if (ticks < tb_ticks_per_jiffy)
ticks = tb_ticks_per_jiffy - ticks;
else
ticks = 1;
set_dec(ticks);
}

#ifdef CONFIG_SUSPEND
void generic_suspend_disable_irqs(void)
static void generic_suspend_disable_irqs(void)
{
preempt_disable();

/* Disable the decrementer, so that it doesn't interfere
* with suspending.
*/
Expand All @@ -673,12 +640,9 @@ void generic_suspend_disable_irqs(void)
set_dec(0x7fffffff);
}

void generic_suspend_enable_irqs(void)
static void generic_suspend_enable_irqs(void)
{
wakeup_decrementer();

local_irq_enable();
preempt_enable();
}

/* Overrides the weak version in kernel/power/main.c */
Expand All @@ -698,23 +662,6 @@ void arch_suspend_enable_irqs(void)
}
#endif

#ifdef CONFIG_SMP
void __init smp_space_timers(unsigned int max_cpus)
{
int i;
u64 previous_tb = per_cpu(last_jiffy, boot_cpuid);

/* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
previous_tb -= tb_ticks_per_jiffy;

for_each_possible_cpu(i) {
if (i == boot_cpuid)
continue;
per_cpu(last_jiffy, i) = previous_tb;
}
}
#endif

/*
* Scheduler clock - returns current time in nanosec units.
*
Expand Down Expand Up @@ -853,6 +800,7 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
struct clocksource *clock, u32 mult)
{
u64 new_tb_to_xs, new_stamp_xsec;
u32 frac_sec;

if (clock != &clocksource_timebase)
return;
Expand All @@ -868,6 +816,10 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
do_div(new_stamp_xsec, 1000000000);
new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;

BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
/* this is tv_nsec / 1e9 as a 0.32 fraction */
frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;

/*
* 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
Expand All @@ -885,6 +837,7 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
vdso_data->wtom_clock_sec = wtm->tv_sec;
vdso_data->wtom_clock_nsec = wtm->tv_nsec;
vdso_data->stamp_xtime = *wall_time;
vdso_data->stamp_sec_fraction = frac_sec;
smp_wmb();
++(vdso_data->tb_update_count);
}
Expand Down Expand Up @@ -1002,65 +955,28 @@ void secondary_cpu_time_init(void)
/* This function is only called on the boot processor */
void __init time_init(void)
{
unsigned long flags;
struct div_result res;
u64 scale, x;
u64 scale;
unsigned shift;

if (__USE_RTC()) {
/* 601 processor: dec counts down by 128 every 128ns */
ppc_tb_freq = 1000000000;
tb_last_jiffy = get_rtcl();
} else {
/* Normal PowerPC with timebase register */
ppc_md.calibrate_decr();
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_jiffy = get_tb();
}

tb_ticks_per_jiffy = ppc_tb_freq / HZ;
tb_ticks_per_sec = ppc_tb_freq;
tb_ticks_per_usec = ppc_tb_freq / 1000000;
tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
calc_cputime_factors();
setup_cputime_one_jiffy();

/*
* Calculate the length of each tick in ns. It will not be
* exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
* We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
* rounded up.
*/
x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1;
do_div(x, ppc_tb_freq);
tick_nsec = x;
last_tick_len = x << TICKLEN_SCALE;

/*
* Compute ticklen_to_xs, which is a factor which gets multiplied
* by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
* It is computed as:
* ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
* where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
* which turns out to be N = 51 - SHIFT_HZ.
* This gives the result as a 0.64 fixed-point fraction.
* That value is reduced by an offset amounting to 1 xsec per
* 2^31 timebase ticks to avoid problems with time going backwards
* by 1 xsec when we do timer_recalc_offset due to losing the
* fractional xsec. That offset is equal to ppc_tb_freq/2^51
* since there are 2^20 xsec in a second.
*/
div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
tb_ticks_per_jiffy << SHIFT_HZ, &res);
div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
ticklen_to_xs = res.result_low;

/* Compute tb_to_xs from tick_nsec */
tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs);

/*
* Compute scale factor for sched_clock.
* The calibrate_decr() function has set tb_ticks_per_sec,
Expand All @@ -1082,21 +998,14 @@ void __init time_init(void)
/* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
boot_tb = get_tb_or_rtc();

write_seqlock_irqsave(&xtime_lock, flags);

/* If platform provided a timezone (pmac), we correct the time */
if (timezone_offset) {
sys_tz.tz_minuteswest = -timezone_offset / 60;
sys_tz.tz_dsttime = 0;
}

vdso_data->tb_orig_stamp = tb_last_jiffy;
vdso_data->tb_update_count = 0;
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
vdso_data->stamp_xsec = (u64) get_seconds() * XSEC_PER_SEC;
vdso_data->tb_to_xs = tb_to_xs;

write_sequnlock_irqrestore(&xtime_lock, flags);

/* Start the decrementer on CPUs that have manual control
* such as BookE
Expand Down Expand Up @@ -1190,39 +1099,6 @@ void to_tm(int tim, struct rtc_time * tm)
GregorianDay(tm);
}

/* Auxiliary function to compute scaling factors */
/* Actually the choice of a timebase running at 1/4 the of the bus
* frequency giving resolution of a few tens of nanoseconds is quite nice.
* It makes this computation very precise (27-28 bits typically) which
* is optimistic considering the stability of most processor clock
* oscillators and the precision with which the timebase frequency
* is measured but does not harm.
*/
unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale)
{
unsigned mlt=0, tmp, err;
/* No concern for performance, it's done once: use a stupid
* but safe and compact method to find the multiplier.
*/

for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
if (mulhwu(inscale, mlt|tmp) < outscale)
mlt |= tmp;
}

/* We might still be off by 1 for the best approximation.
* A side effect of this is that if outscale is too large
* the returned value will be zero.
* Many corner cases have been checked and seem to work,
* some might have been forgotten in the test however.
*/

err = inscale * (mlt+1);
if (err <= inscale/2)
mlt++;
return mlt;
}

/*
* Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
* result.
Expand Down

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