lwn.git/arch/powerpc/kernel/time.c, branch docs-next-merge

powerpc32: provide VIRT_CPU_ACCOUNTING

2016-07-09T06:43:50+00:00

This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture. PPC32 doesn't have the PACA structure, so we use the task_info structure to store the accounting data. In order to reuse on PPC32 the PPC64 functions, all u64 data has been replaced by 'unsigned long' so that it is u32 on PPC32 and u64 on PPC64 Signed-off-by: Christophe Leroy Signed-off-by: Scott Wood

powerpc/timer: Large Decrementer support

2016-07-05T13:58:53+00:00

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: Oliver O'Halloran Signed-off-by: Balbir Singh Acked-by: Michael Neuling Signed-off-by: Michael Ellerman

powerpc: sparse: Include headers for __weak symbols

2016-04-12T11:05:19+00:00

Sometimes when sparse warns about undefined symbols, it isn't because they should have 'static' added, it's because they're overriding __weak symbols defined elsewhere, and the header has been missed. Fix a few of them by adding appropriate headers. Signed-off-by: Daniel Axtens Signed-off-by: Michael Ellerman

powerpc: Remove broken GregorianDay()

2015-12-16T01:54:04+00:00

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 Cc: Andrew Morton # as an example of what UBSan finds. Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: rtc-linux@googlegroups.com Signed-off-by: Daniel Axtens Acked-by: Alexandre Belloni Signed-off-by: Michael Ellerman

powerpc/time: Migrate to new 'set-state' interface

2015-08-10T09:41:02+00:00

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 Cc: Paul Mackerras Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Viresh Kumar Signed-off-by: Daniel Lezcano

powerpc: use device_initcall for registering rtc devices

2015-06-16T18:12:29+00:00

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 Cc: Paul Mackerras Cc: Geoff Levand Acked-by: Geoff Levand Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Paul Gortmaker

KVM: PPC: Book3S HV: Accumulate timing information for real-mode code

2015-04-21T13:21:31+00:00

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: Paul Mackerras Signed-off-by: Alexander Graf

Merge tag 'clk-for-linus-3.20' of git://git.linaro.org/people/mike.turquette/linux

2015-02-21T20:30:30+00:00

Pull clock framework updates from Mike Turquette: "The clock framework changes contain the usual driver additions, enhancements and fixes mostly for ARM32, ARM64, MIPS and Power-based devices. Additionally the framework core underwent a bit of surgery with two major changes: - The boundary between the clock core and clock providers (e.g clock drivers) is now more well defined with dedicated provider helper functions. struct clk no longer maps 1:1 with the hardware clock but is a true per-user cookie which helps us tracker users of hardware clocks and debug bad behavior. - The addition of rate constraints for clocks. Rate ranges are now supported which are analogous to the voltage ranges in the regulator framework. Unfortunately these changes to the core created some breakeage. We think we fixed it all up but for this reason there are lots of last minute commits trying to undo the damage" * tag 'clk-for-linus-3.20' of git://git.linaro.org/people/mike.turquette/linux: (113 commits) clk: Only recalculate the rate if needed Revert "clk: mxs: Fix invalid 32-bit access to frac registers" clk: qoriq: Add support for the platform PLL powerpc/corenet: Enable CLK_QORIQ clk: Replace explicit clk assignment with __clk_hw_set_clk clk: Add __clk_hw_set_clk helper function clk: Don't dereference parent clock if is NULL MIPS: Alchemy: Remove bogus args from alchemy_clk_fgcs_detr clkdev: Always allocate a struct clk and call __clk_get() w/ CCF clk: shmobile: div6: Avoid division by zero in .round_rate() clk: mxs: Fix invalid 32-bit access to frac registers clk: omap: compile legacy omap3 clocks conditionally clkdev: Export clk_register_clkdev clk: Add rate constraints to clocks clk: remove clk-private.h pci: xgene: do not use clk-private.h arm: omap2+ remove dead clock code clk: Make clk API return per-user struct clk instances clk: tegra: Define PLLD_DSI and remove dsia(b)_mux clk: tegra: Add support for the Tegra132 CAR IP block ...

powerpc: add running_clock for powerpc to prevent spurious softlockup warnings

2015-02-13T02:54:13+00:00

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: Cyril Bur Cc: Michael Ellerman Cc: Andrew Jones Acked-by: Don Zickus Cc: Ingo Molnar Cc: Ulrich Obergfell Cc: chai wen Cc: Fabian Frederick Cc: Aaron Tomlin Cc: Ben Zhang Cc: Martin Schwidefsky Cc: John Stultz Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc: call of_clk_init() from time_init()

2015-01-20T18:09:02+00:00

So the boards which has COMMON_CLK enabled don't have to invoke this in its board specific file. Signed-off-by: Kevin Hao Acked-by: Scott Wood Acked-by: Michael Turquette Signed-off-by: Michael Turquette