1. 25 12月, 2016 2 次提交
  2. 15 11月, 2016 2 次提交
  3. 13 9月, 2016 1 次提交
  4. 08 8月, 2016 1 次提交
  5. 09 7月, 2016 1 次提交
  6. 05 7月, 2016 1 次提交
    • O
      powerpc/timer: Large Decrementer support · 79901024
      Oliver O'Halloran 提交于
      Power ISAv3 adds a large decrementer (LD) mode which increases the size
      of the decrementer register. The size of the enlarged decrementer
      register is between 32 and 64 bits with the exact size being dependent
      on the implementation. When in LD mode, reads are sign extended to 64
      bits and a decrementer exception is raised when the high bit is set (i.e
      the value goes below zero). Writes however are truncated to the physical
      register width so some care needs to be taken to ensure that the high
      bit is not set when reloading the decrementer. This patch adds support
      for using the LD inside the host kernel on processors that support it.
      
      When LD mode is supported firmware will supply the ibm,dec-bits property
      for CPU nodes to allow the kernel to determine the maximum decrementer
      value. Enabling LD mode is a hypervisor privileged operation so the kernel
      can only enable it manually when running in hypervisor mode. Guests that
      support LD mode can request it using the "ibm,client-architecture-support"
      firmware call (not implemented in this patch) or some other platform
      specific method. If this property is not supplied then the traditional
      decrementer width of 32 bit is assumed and LD mode will not be enabled.
      
      This patch was based on initial work by Jack Miller.
      Signed-off-by: NOliver O'Halloran <oohall@gmail.com>
      Signed-off-by: NBalbir Singh <bsingharora@gmail.com>
      Acked-by: NMichael Neuling <mikey@neuling.org>
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      79901024
  7. 04 6月, 2016 1 次提交
  8. 12 4月, 2016 1 次提交
  9. 16 12月, 2015 1 次提交
    • D
      powerpc: Remove broken GregorianDay() · 00b912b0
      Daniel Axtens 提交于
      GregorianDay() is supposed to calculate the day of the week
      (tm->tm_wday) for a given day/month/year. In that calcuation it
      indexed into an array called MonthOffset using tm->tm_mon-1. However
      tm_mon is zero-based, not one-based, so this is off-by-one. It also
      means that every January, GregoiranDay() will access element -1 of
      the MonthOffset array.
      
      It also doesn't appear to be a correct algorithm either: see in
      contrast kernel/time/timeconv.c's time_to_tm function.
      
      It's been broken forever, which suggests no-one in userland uses
      this. It looks like no-one in the kernel uses tm->tm_wday either
      (see e.g. drivers/rtc/rtc-ds1305.c:319).
      
      tm->tm_wday is conventionally set to -1 when not available in
      hardware so we can simply set it to -1 and drop the function.
      (There are over a dozen other drivers in drivers/rtc that do
      this.)
      
      Found using UBSAN.
      
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Andrew Morton <akpm@linux-foundation.org> # as an example of what UBSan finds.
      Cc: Alessandro Zummo <a.zummo@towertech.it>
      Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
      Cc: rtc-linux@googlegroups.com
      Signed-off-by: NDaniel Axtens <dja@axtens.net>
      Acked-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      00b912b0
  10. 10 8月, 2015 1 次提交
    • V
      powerpc/time: Migrate to new 'set-state' interface · 37a13e78
      Viresh Kumar 提交于
      Migrate powerpc driver to the new 'set-state' interface provided by
      clockevents core, the earlier 'set-mode' interface is marked obsolete
      now.
      
      This also enables us to implement callbacks for new states of clockevent
      devices, for example: ONESHOT_STOPPED.
      
      We weren't doing anything in ->set_mode(ONSHOT) and so
      set_state_oneshot() isn't implemented.
      
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: linuxppc-dev@lists.ozlabs.org
      Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
      Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
      37a13e78
  11. 17 6月, 2015 1 次提交
    • P
      powerpc: use device_initcall for registering rtc devices · 8f6b9512
      Paul Gortmaker 提交于
      Currently these two RTC devices are in core platform code
      where it is not possible for them to be modular.  It will
      never be modular, so using module_init as an alias for
      __initcall can be somewhat misleading.
      
      Fix this up now, so that we can relocate module_init from
      init.h into module.h in the future.  If we don't do this, we'd
      have to add module.h to obviously non-modular code, and that
      would be a worse thing.
      
      Note that direct use of __initcall is discouraged, vs. one
      of the priority categorized subgroups.  As __initcall gets
      mapped onto device_initcall, our use of device_initcall
      directly in this change means that the runtime impact is
      zero -- they will remain at level 6 in initcall ordering.
      
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Geoff Levand <geoff@infradead.org>
      Acked-by: NGeoff Levand <geoff@infradead.org>
      Cc: linuxppc-dev@lists.ozlabs.org
      Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      8f6b9512
  12. 21 4月, 2015 1 次提交
    • P
      KVM: PPC: Book3S HV: Accumulate timing information for real-mode code · b6c295df
      Paul Mackerras 提交于
      This reads the timebase at various points in the real-mode guest
      entry/exit code and uses that to accumulate total, minimum and
      maximum time spent in those parts of the code.  Currently these
      times are accumulated per vcpu in 5 parts of the code:
      
      * rm_entry - time taken from the start of kvmppc_hv_entry() until
        just before entering the guest.
      * rm_intr - time from when we take a hypervisor interrupt in the
        guest until we either re-enter the guest or decide to exit to the
        host.  This includes time spent handling hcalls in real mode.
      * rm_exit - time from when we decide to exit the guest until the
        return from kvmppc_hv_entry().
      * guest - time spend in the guest
      * cede - time spent napping in real mode due to an H_CEDE hcall
        while other threads in the same vcore are active.
      
      These times are exposed in debugfs in a directory per vcpu that
      contains a file called "timings".  This file contains one line for
      each of the 5 timings above, with the name followed by a colon and
      4 numbers, which are the count (number of times the code has been
      executed), the total time, the minimum time, and the maximum time,
      all in nanoseconds.
      
      The overhead of the extra code amounts to about 30ns for an hcall that
      is handled in real mode (e.g. H_SET_DABR), which is about 25%.  Since
      production environments may not wish to incur this overhead, the new
      code is conditional on a new config symbol,
      CONFIG_KVM_BOOK3S_HV_EXIT_TIMING.
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NAlexander Graf <agraf@suse.de>
      b6c295df
  13. 13 2月, 2015 1 次提交
    • C
      powerpc: add running_clock for powerpc to prevent spurious softlockup warnings · 4be1b297
      Cyril Bur 提交于
      On POWER8 virtualised kernels the VTB register can be read to have a view
      of time that only increases while the guest is running.  This will prevent
      guests from seeing time jump if a guest is paused for significant amounts
      of time.
      
      On POWER7 and below virtualised kernels stolen time is subtracted from
      local_clock as a best effort approximation.  This will not eliminate
      spurious warnings in the case of a suspended guest but may reduce the
      occurance in the case of softlockups due to host over commit.
      
      Bare metal kernels should avoid reading the VTB as KVM does not restore
      sane values when not executing, the approxmation is fine as host kernels
      won't observe any stolen time.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: NCyril Bur <cyrilbur@gmail.com>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Andrew Jones <drjones@redhat.com>
      Acked-by: NDon Zickus <dzickus@redhat.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Ulrich Obergfell <uobergfe@redhat.com>
      Cc: chai wen <chaiw.fnst@cn.fujitsu.com>
      Cc: Fabian Frederick <fabf@skynet.be>
      Cc: Aaron Tomlin <atomlin@redhat.com>
      Cc: Ben Zhang <benzh@chromium.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: John Stultz <john.stultz@linaro.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4be1b297
  14. 21 1月, 2015 1 次提交
  15. 17 11月, 2014 1 次提交
    • N
      rtc/tpo: Driver to support rtc and wakeup on PowerNV platform · 16b1d26e
      Neelesh Gupta 提交于
      The patch implements the OPAL rtc driver that binds with the rtc
      driver subsystem. The driver uses the platform device infrastructure
      to probe the rtc device and register it to rtc class framework. The
      'wakeup' is supported depending upon the property 'has-tpo' present
      in the OF node. It provides a way to load the generic rtc driver in
      in the absence of an OPAL driver.
      
      The patch also moves the existing OPAL rtc get/set time interfaces to the
      new driver and exposes the necessary OPAL calls using EXPORT_SYMBOL_GPL.
      
      Test results:
      -------------
      Host:
      [root@tul169p1 ~]# ls -l /sys/class/rtc/
      total 0
      lrwxrwxrwx 1 root root 0 Oct 14 03:07 rtc0 -> ../../devices/opal-rtc/rtc/rtc0
      [root@tul169p1 ~]# cat /sys/devices/opal-rtc/rtc/rtc0/time
      08:10:07
      [root@tul169p1 ~]# echo `date '+%s' -d '+ 2 minutes'` > /sys/class/rtc/rtc0/wakealarm
      [root@tul169p1 ~]# cat /sys/class/rtc/rtc0/wakealarm
      1413274345
      [root@tul169p1 ~]#
      
      FSP:
      $ smgr mfgState
      standby
      $ rtim timeofday
      
      System time is valid: 2014/10/14 08:12:04.225115
      
      $ smgr mfgState
      ipling
      $
      
      CC: devicetree@vger.kernel.org
      CC: tglx@linutronix.de
      CC: rtc-linux@googlegroups.com
      CC: a.zummo@towertech.it
      Signed-off-by: NNeelesh Gupta <neelegup@linux.vnet.ibm.com>
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      16b1d26e
  16. 03 11月, 2014 1 次提交
    • C
      powerpc: Replace __get_cpu_var uses · 69111bac
      Christoph Lameter 提交于
      This still has not been merged and now powerpc is the only arch that does
      not have this change. Sorry about missing linuxppc-dev before.
      
      V2->V2
        - Fix up to work against 3.18-rc1
      
      __get_cpu_var() is used for multiple purposes in the kernel source. One of
      them is address calculation via the form &__get_cpu_var(x).  This calculates
      the address for the instance of the percpu variable of the current processor
      based on an offset.
      
      Other use cases are for storing and retrieving data from the current
      processors percpu area.  __get_cpu_var() can be used as an lvalue when
      writing data or on the right side of an assignment.
      
      __get_cpu_var() is defined as :
      
      __get_cpu_var() always only does an address determination. However, store
      and retrieve operations could use a segment prefix (or global register on
      other platforms) to avoid the address calculation.
      
      this_cpu_write() and this_cpu_read() can directly take an offset into a
      percpu area and use optimized assembly code to read and write per cpu
      variables.
      
      This patch converts __get_cpu_var into either an explicit address
      calculation using this_cpu_ptr() or into a use of this_cpu operations that
      use the offset.  Thereby address calculations are avoided and less registers
      are used when code is generated.
      
      At the end of the patch set all uses of __get_cpu_var have been removed so
      the macro is removed too.
      
      The patch set includes passes over all arches as well. Once these operations
      are used throughout then specialized macros can be defined in non -x86
      arches as well in order to optimize per cpu access by f.e.  using a global
      register that may be set to the per cpu base.
      
      Transformations done to __get_cpu_var()
      
      1. Determine the address of the percpu instance of the current processor.
      
      	DEFINE_PER_CPU(int, y);
      	int *x = &__get_cpu_var(y);
      
          Converts to
      
      	int *x = this_cpu_ptr(&y);
      
      2. Same as #1 but this time an array structure is involved.
      
      	DEFINE_PER_CPU(int, y[20]);
      	int *x = __get_cpu_var(y);
      
          Converts to
      
      	int *x = this_cpu_ptr(y);
      
      3. Retrieve the content of the current processors instance of a per cpu
      variable.
      
      	DEFINE_PER_CPU(int, y);
      	int x = __get_cpu_var(y)
      
         Converts to
      
      	int x = __this_cpu_read(y);
      
      4. Retrieve the content of a percpu struct
      
      	DEFINE_PER_CPU(struct mystruct, y);
      	struct mystruct x = __get_cpu_var(y);
      
         Converts to
      
      	memcpy(&x, this_cpu_ptr(&y), sizeof(x));
      
      5. Assignment to a per cpu variable
      
      	DEFINE_PER_CPU(int, y)
      	__get_cpu_var(y) = x;
      
         Converts to
      
      	__this_cpu_write(y, x);
      
      6. Increment/Decrement etc of a per cpu variable
      
      	DEFINE_PER_CPU(int, y);
      	__get_cpu_var(y)++
      
         Converts to
      
      	__this_cpu_inc(y)
      
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      CC: Paul Mackerras <paulus@samba.org>
      Signed-off-by: NChristoph Lameter <cl@linux.com>
      [mpe: Fix build errors caused by set/or_softirq_pending(), and rework
            assignment in __set_breakpoint() to use memcpy().]
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      69111bac
  17. 25 9月, 2014 2 次提交
  18. 27 8月, 2014 2 次提交
    • T
      Revert "powerpc: Replace __get_cpu_var uses" · 23f66e2d
      Tejun Heo 提交于
      This reverts commit 5828f666 due to
      build failure after merging with pending powerpc changes.
      
      Link: http://lkml.kernel.org/g/20140827142243.6277eaff@canb.auug.org.auSigned-off-by: NTejun Heo <tj@kernel.org>
      Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      23f66e2d
    • C
      powerpc: Replace __get_cpu_var uses · 5828f666
      Christoph Lameter 提交于
      __get_cpu_var() is used for multiple purposes in the kernel source. One of
      them is address calculation via the form &__get_cpu_var(x).  This calculates
      the address for the instance of the percpu variable of the current processor
      based on an offset.
      
      Other use cases are for storing and retrieving data from the current
      processors percpu area.  __get_cpu_var() can be used as an lvalue when
      writing data or on the right side of an assignment.
      
      __get_cpu_var() is defined as :
      
      #define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
      
      __get_cpu_var() always only does an address determination. However, store
      and retrieve operations could use a segment prefix (or global register on
      other platforms) to avoid the address calculation.
      
      this_cpu_write() and this_cpu_read() can directly take an offset into a
      percpu area and use optimized assembly code to read and write per cpu
      variables.
      
      This patch converts __get_cpu_var into either an explicit address
      calculation using this_cpu_ptr() or into a use of this_cpu operations that
      use the offset.  Thereby address calculations are avoided and less registers
      are used when code is generated.
      
      At the end of the patch set all uses of __get_cpu_var have been removed so
      the macro is removed too.
      
      The patch set includes passes over all arches as well. Once these operations
      are used throughout then specialized macros can be defined in non -x86
      arches as well in order to optimize per cpu access by f.e.  using a global
      register that may be set to the per cpu base.
      
      Transformations done to __get_cpu_var()
      
      1. Determine the address of the percpu instance of the current processor.
      
      	DEFINE_PER_CPU(int, y);
      	int *x = &__get_cpu_var(y);
      
          Converts to
      
      	int *x = this_cpu_ptr(&y);
      
      2. Same as #1 but this time an array structure is involved.
      
      	DEFINE_PER_CPU(int, y[20]);
      	int *x = __get_cpu_var(y);
      
          Converts to
      
      	int *x = this_cpu_ptr(y);
      
      3. Retrieve the content of the current processors instance of a per cpu
      variable.
      
      	DEFINE_PER_CPU(int, y);
      	int x = __get_cpu_var(y)
      
         Converts to
      
      	int x = __this_cpu_read(y);
      
      4. Retrieve the content of a percpu struct
      
      	DEFINE_PER_CPU(struct mystruct, y);
      	struct mystruct x = __get_cpu_var(y);
      
         Converts to
      
      	memcpy(&x, this_cpu_ptr(&y), sizeof(x));
      
      5. Assignment to a per cpu variable
      
      	DEFINE_PER_CPU(int, y)
      	__get_cpu_var(y) = x;
      
         Converts to
      
      	__this_cpu_write(y, x);
      
      6. Increment/Decrement etc of a per cpu variable
      
      	DEFINE_PER_CPU(int, y);
      	__get_cpu_var(y)++
      
         Converts to
      
      	__this_cpu_inc(y)
      
      tj: Folded a fix patch.
          http://lkml.kernel.org/g/alpine.DEB.2.11.1408172143020.9652@gentwo.org
      
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      CC: Paul Mackerras <paulus@samba.org>
      Signed-off-by: NChristoph Lameter <cl@linux.com>
      Signed-off-by: NTejun Heo <tj@kernel.org>
      5828f666
  19. 24 7月, 2014 1 次提交
  20. 11 6月, 2014 1 次提交
  21. 12 5月, 2014 1 次提交
    • A
      powerpc: irq work racing with timer interrupt can result in timer interrupt hang · 8050936c
      Anton Blanchard 提交于
      I am seeing an issue where a CPU running perf eventually hangs.
      Traces show timer interrupts happening every 4 seconds even
      when a userspace task is running on the CPU. /proc/timer_list
      also shows pending hrtimers have not run in over an hour,
      including the scheduler.
      
      Looking closer, decrementers_next_tb is getting set to
      0xffffffffffffffff, and at that point we will never take
      a timer interrupt again.
      
      In __timer_interrupt() we set decrementers_next_tb to
      0xffffffffffffffff and rely on ->event_handler to update it:
      
              *next_tb = ~(u64)0;
              if (evt->event_handler)
                      evt->event_handler(evt);
      
      In this case ->event_handler is hrtimer_interrupt. This will eventually
      call back through the clockevents code with the next event to be
      programmed:
      
      static int decrementer_set_next_event(unsigned long evt,
                                            struct clock_event_device *dev)
      {
              /* Don't adjust the decrementer if some irq work is pending */
              if (test_irq_work_pending())
                      return 0;
              __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;
      
      If irq work came in between these two points, we will return
      before updating decrementers_next_tb and we never process a timer
      interrupt again.
      
      This looks to have been introduced by 0215f7d8 (powerpc: Fix races
      with irq_work). Fix it by removing the early exit and relying on
      code later on in the function to force an early decrementer:
      
             /* We may have raced with new irq work */
             if (test_irq_work_pending())
                     set_dec(1);
      Signed-off-by: NAnton Blanchard <anton@samba.org>
      Cc: stable@vger.kernel.org # 3.14+
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      8050936c
  22. 05 3月, 2014 3 次提交
  23. 15 1月, 2014 1 次提交
    • B
      powerpc: Fix races with irq_work · 0215f7d8
      Benjamin Herrenschmidt 提交于
      If we set irq_work on a processor and immediately afterward, before the
      irq work has a chance to be processed, we change the decrementer value,
      we can seriously delay the handling of that irq_work.
      
      Fix it by checking in a few places for pending irq work, first before
      changing the decrementer in decrementer_set_next_event() and after
      changing it in the same function and in timer_interrupt().
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      0215f7d8
  24. 02 12月, 2013 1 次提交
  25. 21 11月, 2013 1 次提交
    • A
      powerpc/pseries: Duplicate dtl entries sometimes sent to userspace · 84b07386
      Anton Blanchard 提交于
      When reading from the dispatch trace log (dtl) userspace interface, I
      sometimes see duplicate entries. One example:
      
      # hexdump -C dtl.out
      
      00000000  07 04 00 0c 00 00 48 44  00 00 00 00 00 00 00 00
      00000010  00 0c a0 b4 16 83 6d 68  00 00 00 00 00 00 00 00
      00000020  00 00 00 00 10 00 13 50  80 00 00 00 00 00 d0 32
      
      00000030  07 04 00 0c 00 00 48 44  00 00 00 00 00 00 00 00
      00000040  00 0c a0 b4 16 83 6d 68  00 00 00 00 00 00 00 00
      00000050  00 00 00 00 10 00 13 50  80 00 00 00 00 00 d0 32
      
      The problem is in scan_dispatch_log() where we call dtl_consumer()
      but bail out before incrementing the index.
      
      To fix this I moved dtl_consumer() after the timebase comparison.
      Signed-off-by: NAnton Blanchard <anton@samba.org>
      Cc: stable@vger.kernel.org
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      84b07386
  26. 14 8月, 2013 2 次提交
  27. 15 7月, 2013 1 次提交
  28. 01 7月, 2013 1 次提交
    • P
      powerpc: Delete __cpuinit usage from all users · 061d19f2
      Paul Gortmaker 提交于
      The __cpuinit type of throwaway sections might have made sense
      some time ago when RAM was more constrained, but now the savings
      do not offset the cost and complications.  For example, the fix in
      commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
      is a good example of the nasty type of bugs that can be created
      with improper use of the various __init prefixes.
      
      After a discussion on LKML[1] it was decided that cpuinit should go
      the way of devinit and be phased out.  Once all the users are gone,
      we can then finally remove the macros themselves from linux/init.h.
      
      This removes all the powerpc uses of the __cpuinit macros.  There
      are no __CPUINIT users in assembly files in powerpc.
      
      [1] https://lkml.org/lkml/2013/5/20/589
      
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Josh Boyer <jwboyer@gmail.com>
      Cc: Matt Porter <mporter@kernel.crashing.org>
      Cc: Kumar Gala <galak@kernel.crashing.org>
      Cc: linuxppc-dev@lists.ozlabs.org
      Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      061d19f2
  29. 18 4月, 2013 1 次提交
  30. 29 1月, 2013 1 次提交
  31. 28 1月, 2013 2 次提交
    • F
      kvm: Prepare to add generic guest entry/exit callbacks · c11f11fc
      Frederic Weisbecker 提交于
      Do some ground preparatory work before adding guest_enter()
      and guest_exit() context tracking callbacks. Those will
      be later used to read the guest cputime safely when we
      run in full dynticks mode.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Gleb Natapov <gleb@redhat.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      c11f11fc
    • F
      cputime: Generic on-demand virtual cputime accounting · abf917cd
      Frederic Weisbecker 提交于
      If we want to stop the tick further idle, we need to be
      able to account the cputime without using the tick.
      
      Virtual based cputime accounting solves that problem by
      hooking into kernel/user boundaries.
      
      However implementing CONFIG_VIRT_CPU_ACCOUNTING require
      low level hooks and involves more overhead. But we already
      have a generic context tracking subsystem that is required
      for RCU needs by archs which plan to shut down the tick
      outside idle.
      
      This patch implements a generic virtual based cputime
      accounting that relies on these generic kernel/user hooks.
      
      There are some upsides of doing this:
      
      - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING
      if context tracking is already built (already necessary for RCU in full
      tickless mode).
      
      - We can rely on the generic context tracking subsystem to dynamically
      (de)activate the hooks, so that we can switch anytime between virtual
      and tick based accounting. This way we don't have the overhead
      of the virtual accounting when the tick is running periodically.
      
      And one downside:
      
      - There is probably more overhead than a native virtual based cputime
      accounting. But this relies on hooks that are already set anyway.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      abf917cd
  32. 16 1月, 2013 1 次提交
    • J
      NTP: Add a CONFIG_RTC_SYSTOHC configuration · 023f333a
      Jason Gunthorpe 提交于
      The purpose of this option is to allow ARM/etc systems that rely on the
      class RTC subsystem to have the same kind of automatic NTP based
      synchronization that we have on PC platforms. Today ARM does not
      implement update_persistent_clock and makes extensive use of the class
      RTC system.
      
      When enabled CONFIG_RTC_SYSTOHC will provide a generic
      rtc_update_persistent_clock that stores the current time in the RTC and
      is intended complement the existing CONFIG_RTC_HCTOSYS option that loads
      the RTC at boot.
      
      Like with RTC_HCTOSYS the platform's update_persistent_clock is used
      first, if it works. Platforms with mixed class RTC and non-RTC drivers
      need to return ENODEV when class RTC should be used. Such an update for
      PPC is included in this patch.
      
      Long term, implementations of update_persistent_clock should migrate to
      proper class RTC drivers and use CONFIG_RTC_SYSTOHC instead.
      
      Tested on ARM kirkwood and PPC405
      Signed-off-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
      Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
      023f333a