We noticed that recent kernels didn't boot on our 1GHz Canyonlands 460EX
boards anymore. As it seems, patch 8d165db1 [powerpc: Improve
decrementer accuracy] introduced this problem. The routine div_sc()
overflows with shift = 32 resulting in this incorrect setup:

time_init: decrementer frequency = 1000.000012 MHz
time_init: processor frequency   = 1000.000012 MHz
clocksource: timebase mult[400000] shift[22] registered
clockevent: decrementer mult[33] shift[32] cpu[0]

This patch now introduces a local div_dc64() version of this function
so that this overflow doesn't happen anymore.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Detlev Zundel <dzu@denx.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (151 commits)
  powerpc: Fix usage of 64-bit instruction in 32-bit altivec code
  MAINTAINERS: Add PowerPC patterns
  powerpc/pseries: Track previous CPPR values to correctly EOI interrupts
  powerpc/pseries: Correct pseries/dlpar.c build break without CONFIG_SMP
  powerpc: Make "intspec" pointers in irq_host->xlate() const
  powerpc/8xx: DTLB Miss cleanup
  powerpc/8xx: Remove DIRTY pte handling in DTLB Error.
  powerpc/8xx: Start using dcbX instructions in various copy routines
  powerpc/8xx: Restore _PAGE_WRITETHRU
  powerpc/8xx: Add missing Guarded setting in DTLB Error.
  powerpc/8xx: Fixup DAR from buggy dcbX instructions.
  powerpc/8xx: Tag DAR with 0x00f0 to catch buggy instructions.
  powerpc/8xx: Update TLB asm so it behaves as linux mm expects.
  powerpc/8xx: Invalidate non present TLBs
  powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate
  pseries/pseries: Add code to online/offline CPUs of a DLPAR node
  powerpc: stop_this_cpu: remove the cpu from the online map.
  powerpc/pseries: Add kernel based CPU DLPAR handling
  sysfs/cpu: Add probe/release files
  powerpc/pseries: Kernel DLPAR Infrastructure
  ...

Conflicts:
	include/linux/kvm.h

* 'timers-for-linus-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimer: Fix /proc/timer_list regression
  itimers: Fix racy writes to cpu_itimer fields
  timekeeping: Fix clock_gettime vsyscall time warp

* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  timers, init: Limit the number of per cpu calibration bootup messages
  posix-cpu-timers: optimize and document timer_create callback
  clockevents: Add missing include to pacify sparse
  x86: vmiclock: Fix printk format
  x86: Fix printk format due to variable type change
  sparc: fix printk for change of variable type
  clocksource/events: Fix fallout of generic code changes
  nohz: Allow 32-bit machines to sleep for more than 2.15 seconds
  nohz: Track last do_timer() cpu
  nohz: Prevent clocksource wrapping during idle
  nohz: Type cast printk argument
  mips: Use generic mult/shift factor calculation for clocks
  clocksource: Provide a generic mult/shift factor calculation
  clockevents: Use u32 for mult and shift factors
  nohz: Introduce arch_needs_cpu
  nohz: Reuse ktime in sub-functions of tick_check_idle.
  time: Remove xtime_cache
  time: Implement logarithmic time accumulation

Since commit 0a544198 "timekeeping: Move NTP adjusted clock multiplier
to struct timekeeper" the clock multiplier of vsyscall is updated with
the unmodified clock multiplier of the clock source and not with the
NTP adjusted multiplier of the timekeeper.

This causes user space observerable time warps:
new CLOCK-warp maximum: 120 nsecs,  00000025c337c537 -> 00000025c337c4bf

Add a new argument "mult" to update_vsyscall() and hand in the
timekeeping internal NTP adjusted multiplier.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: "Zhang Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Merge reason: Both 'perf bench' and the pending PowerPC changes
              are now ready for the next merge window.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

powerpc grew a new warning due to the type change of clockevent->mult.

The architectures which use parts of the generic time keeping
infrastructure tripped over my wrong assumption that
clocksource_register is only used when GENERIC_TIME=y.

I should have looked and also I should have known better. These
renitent Gaul villages are racking my nerves. Some serious deprecating
is due.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Doing so causes xtime to be negative which crashes the timekeeping
code in funny ways when doing suspend/resume

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>