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2021-06-22clocksource: Provide kernel module to test clocksource watchdogPaul E. McKenney1-0/+3
When the clocksource watchdog marks a clock as unstable, this might be due to that clock being unstable or it might be due to delays that happen to occur between the reads of the two clocks. It would be good to have a way of testing the clocksource watchdog's ability to distinguish between these two causes of clock skew and instability. Therefore, provide a new clocksource-wdtest module selected by a new TEST_CLOCKSOURCE_WATCHDOG Kconfig option. This module has a single module parameter named "holdoff" that provides the number of seconds of delay before testing should start, which defaults to zero when built as a module and to 10 seconds when built directly into the kernel. Very large systems that boot slowly may need to increase the value of this module parameter. This module uses hand-crafted clocksource structures to do its testing, thus avoiding messing up timing for the rest of the kernel and for user applications. This module first verifies that the ->uncertainty_margin field of the clocksource structures are set sanely. It then tests the delay-detection capability of the clocksource watchdog, increasing the number of consecutive delays injected, first provoking console messages complaining about the delays and finally forcing a clock-skew event. Unexpected test results cause at least one WARN_ON_ONCE() console splat. If there are no splats, the test has passed. Finally, it fuzzes the value returned from a clocksource to test the clocksource watchdog's ability to detect time skew. This module checks the state of its clocksource after each test, and uses WARN_ON_ONCE() to emit a console splat if there are any failures. This should enable all types of test frameworks to detect any such failures. This facility is intended for diagnostic use only, and should be avoided on production systems. Reported-by: Chris Mason <clm@fb.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Feng Tang <feng.tang@intel.com> Link: https://lore.kernel.org/r/20210527190124.440372-5-paulmck@kernel.org
2021-06-22clocksource: Reduce clocksource-skew thresholdPaul E. McKenney1-0/+3
Currently, WATCHDOG_THRESHOLD is set to detect a 62.5-millisecond skew in a 500-millisecond WATCHDOG_INTERVAL. This requires that clocks be skewed by more than 12.5% in order to be marked unstable. Except that a clock that is skewed by that much is probably destroying unsuspecting software right and left. And given that there are now checks for false-positive skews due to delays between reading the two clocks, it should be possible to greatly decrease WATCHDOG_THRESHOLD, at least for fine-grained clocks such as TSC. Therefore, add a new uncertainty_margin field to the clocksource structure that contains the maximum uncertainty in nanoseconds for the corresponding clock. This field may be initialized manually, as it is for clocksource_tsc_early and clocksource_jiffies, which is copied to refined_jiffies. If the field is not initialized manually, it will be computed at clock-registry time as the period of the clock in question based on the scale and freq parameters to __clocksource_update_freq_scale() function. If either of those two parameters are zero, the tens-of-milliseconds WATCHDOG_THRESHOLD is used as a cowardly alternative to dividing by zero. No matter how the uncertainty_margin field is calculated, it is bounded below by twice WATCHDOG_MAX_SKEW, that is, by 100 microseconds. Note that manually initialized uncertainty_margin fields are not adjusted, but there is a WARN_ON_ONCE() that triggers if any such field is less than twice WATCHDOG_MAX_SKEW. This WARN_ON_ONCE() is intended to discourage production use of the one-nanosecond uncertainty_margin values that are used to test the clock-skew code itself. The actual clock-skew check uses the sum of the uncertainty_margin fields of the two clocksource structures being compared. Integer overflow is avoided because the largest computed value of the uncertainty_margin fields is one billion (10^9), and double that value fits into an unsigned int. However, if someone manually specifies (say) UINT_MAX, they will get what they deserve. Note that the refined_jiffies uncertainty_margin field is initialized to TICK_NSEC, which means that skew checks involving this clocksource will be sufficently forgiving. In a similar vein, the clocksource_tsc_early uncertainty_margin field is initialized to 32*NSEC_PER_MSEC, which replicates the current behavior and allows custom setting if needed in order to address the rare skews detected for this clocksource in current mainline. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Feng Tang <feng.tang@intel.com> Link: https://lore.kernel.org/r/20210527190124.440372-4-paulmck@kernel.org
2021-06-22clocksource: Check per-CPU clock synchronization when marked unstablePaul E. McKenney1-1/+1
Some sorts of per-CPU clock sources have a history of going out of synchronization with each other. However, this problem has purportedy been solved in the past ten years. Except that it is all too possible that the problem has instead simply been made less likely, which might mean that some of the occasional "Marking clocksource 'tsc' as unstable" messages might be due to desynchronization. How would anyone know? Therefore apply CPU-to-CPU synchronization checking to newly unstable clocksource that are marked with the new CLOCK_SOURCE_VERIFY_PERCPU flag. Lists of desynchronized CPUs are printed, with the caveat that if it is the reporting CPU that is itself desynchronized, it will appear that all the other clocks are wrong. Just like in real life. Reported-by: Chris Mason <clm@fb.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Feng Tang <feng.tang@intel.com> Link: https://lore.kernel.org/r/20210527190124.440372-2-paulmck@kernel.org
2021-05-01Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+6
Pull kvm updates from Paolo Bonzini: "This is a large update by KVM standards, including AMD PSP (Platform Security Processor, aka "AMD Secure Technology") and ARM CoreSight (debug and trace) changes. ARM: - CoreSight: Add support for ETE and TRBE - Stage-2 isolation for the host kernel when running in protected mode - Guest SVE support when running in nVHE mode - Force W^X hypervisor mappings in nVHE mode - ITS save/restore for guests using direct injection with GICv4.1 - nVHE panics now produce readable backtraces - Guest support for PTP using the ptp_kvm driver - Performance improvements in the S2 fault handler x86: - AMD PSP driver changes - Optimizations and cleanup of nested SVM code - AMD: Support for virtual SPEC_CTRL - Optimizations of the new MMU code: fast invalidation, zap under read lock, enable/disably dirty page logging under read lock - /dev/kvm API for AMD SEV live migration (guest API coming soon) - support SEV virtual machines sharing the same encryption context - support SGX in virtual machines - add a few more statistics - improved directed yield heuristics - Lots and lots of cleanups Generic: - Rework of MMU notifier interface, simplifying and optimizing the architecture-specific code - a handful of "Get rid of oprofile leftovers" patches - Some selftests improvements" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (379 commits) KVM: selftests: Speed up set_memory_region_test selftests: kvm: Fix the check of return value KVM: x86: Take advantage of kvm_arch_dy_has_pending_interrupt() KVM: SVM: Skip SEV cache flush if no ASIDs have been used KVM: SVM: Remove an unnecessary prototype declaration of sev_flush_asids() KVM: SVM: Drop redundant svm_sev_enabled() helper KVM: SVM: Move SEV VMCB tracking allocation to sev.c KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup() KVM: SVM: Unconditionally invoke sev_hardware_teardown() KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported) KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control variables KVM: SEV: Mask CPUID[0x8000001F].eax according to supported features KVM: SVM: Move SEV module params/variables to sev.c KVM: SVM: Disable SEV/SEV-ES if NPT is disabled KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails KVM: SVM: Zero out the VMCB array used to track SEV ASID association x86/sev: Drop redundant and potentially misleading 'sev_enabled' KVM: x86: Move reverse CPUID helpers to separate header file KVM: x86: Rename GPR accessors to make mode-aware variants the defaults ...
2021-04-07time: Add mechanism to recognize clocksource in time_get_snapshotThomas Gleixner1-0/+6
System time snapshots are not conveying information about the current clocksource which was used, but callers like the PTP KVM guest implementation have the requirement to evaluate the clocksource type to select the appropriate mechanism. Introduce a clocksource id field in struct clocksource which is by default set to CSID_GENERIC (0). Clocksource implementations can set that field to a value which allows to identify the clocksource. Store the clocksource id of the current clocksource in the system_time_snapshot so callers can evaluate which clocksource was used to take the snapshot and act accordingly. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-5-jianyong.wu@arm.com
2021-03-23timekeeping, clocksource: Fix various typos in commentsIngo Molnar1-1/+1
Fix ~56 single-word typos in timekeeping & clocksource code comments. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-kernel@vger.kernel.org
2020-03-21linux/clocksource.h: Extract common header for vDSOVincenzo Frascino1-10/+1
The vDSO library should only include the necessary headers required for a userspace library (UAPI and a minimal set of kernel headers). To make this possible it is necessary to isolate from the kernel headers the common parts that are strictly necessary to build the library. Split clocksource.h into linux and common headers to make the latter suitable for inclusion in the vDSO library. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200320145351.32292-9-vincenzo.frascino@arm.com
2020-02-17lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modesThomas Gleixner1-0/+3
Move the time namespace indicator clock mode to the other ones for consistency sake. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.656097274@linutronix.de
2020-02-17lib/vdso: Cleanup clock mode storage leftoversThomas Gleixner1-2/+2
Now that all architectures are converted to use the generic storage the helpers and conditionals can be removed. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.470699892@linutronix.de
2020-02-17clocksource: Add common vdso clock mode storageThomas Gleixner1-1/+11
All architectures which use the generic VDSO code have their own storage for the VDSO clock mode. That's pointless and just requires duplicate code. Provide generic storage for it. The new Kconfig symbol is intermediate and will be removed once all architectures are converted over. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.028046322@linutronix.de
2020-02-17clocksource: Cleanup struct clocksource and documentationThomas Gleixner1-40/+47
Reformat the struct definition, add missing member documentation. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124402.825471920@linutronix.de
2018-10-25Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-3/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timekeeping updates from Thomas Gleixner: "The timers and timekeeping departement provides: - Another large y2038 update with further preparations for providing the y2038 safe timespecs closer to the syscalls. - An overhaul of the SHCMT clocksource driver - SPDX license identifier updates - Small cleanups and fixes all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) tick/sched : Remove redundant cpu_online() check clocksource/drivers/dw_apb: Add reset control clocksource: Remove obsolete CLOCKSOURCE_OF_DECLARE clocksource/drivers: Unify the names to timer-* format clocksource/drivers/sh_cmt: Add R-Car gen3 support dt-bindings: timer: renesas: cmt: document R-Car gen3 support clocksource/drivers/sh_cmt: Properly line-wrap sh_cmt_of_table[] initializer clocksource/drivers/sh_cmt: Fix clocksource width for 32-bit machines clocksource/drivers/sh_cmt: Fixup for 64-bit machines clocksource/drivers/sh_tmu: Convert to SPDX identifiers clocksource/drivers/sh_mtu2: Convert to SPDX identifiers clocksource/drivers/sh_cmt: Convert to SPDX identifiers clocksource/drivers/renesas-ostm: Convert to SPDX identifiers clocksource: Convert to using %pOFn instead of device_node.name tick/broadcast: Remove redundant check RISC-V: Request newstat syscalls y2038: signal: Change rt_sigtimedwait to use __kernel_timespec y2038: socket: Change recvmmsg to use __kernel_timespec y2038: sched: Change sched_rr_get_interval to use __kernel_timespec y2038: utimes: Rework #ifdef guards for compat syscalls ...
2018-10-05clocksource: Provide clocksource_arch_init()Thomas Gleixner1-0/+5
Architectures have extra archdata in the clocksource, e.g. for VDSO support. There are no sanity checks or general initializations for this available. Add support for that. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andy Lutomirski <luto@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Matt Rickard <matt@softrans.com.au> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Florian Weimer <fweimer@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: devel@linuxdriverproject.org Cc: virtualization@lists.linux-foundation.org Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Juergen Gross <jgross@suse.com> Link: https://lkml.kernel.org/r/20180917130706.973042587@linutronix.de
2018-10-03clocksource: Remove obsolete CLOCKSOURCE_OF_DECLAREDaniel Lezcano1-3/+0
The macro CLOCKSOURCE_OF_DECLARE was renamed more TIMER_OF_DECLARE, and we kept an alias CLOCKSOURCE_OF_DECLARE in order to smooth the transition for drivers. This change was done 1.5 year ago, we can reasonably remove this backward compatible macro as it is no longer used anywhere. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2018-07-20time: Introduce one suspend clocksource to compensate the suspend timeBaolin Wang1-0/+3
On some hardware with multiple clocksources, we have coarse grained clocksources that support the CLOCK_SOURCE_SUSPEND_NONSTOP flag, but which are less than ideal for timekeeping whereas other clocksources can be better candidates but halt on suspend. Currently, the timekeeping core only supports timing suspend using CLOCK_SOURCE_SUSPEND_NONSTOP clocksources if that clocksource is the current clocksource for timekeeping. As a result, some architectures try to implement read_persistent_clock64() using those non-stop clocksources, but isn't really ideal, which will introduce more duplicate code. To fix this, provide logic to allow a registered SUSPEND_NONSTOP clocksource, which isn't the current clocksource, to be used to calculate the suspend time. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Miroslav Lichvar <mlichvar@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Baolin Wang <baolin.wang@linaro.org> [jstultz: minor tweaks to merge with previous resume changes] Signed-off-by: John Stultz <john.stultz@linaro.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-04Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-6/+9
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "A rather large update for timers/timekeeping: - compat syscall consolidation (Al Viro) - Posix timer consolidation (Christoph Helwig / Thomas Gleixner) - Cleanup of the device tree based initialization for clockevents and clocksources (Daniel Lezcano) - Consolidation of the FTTMR010 clocksource/event driver (Linus Walleij) - The usual set of small fixes and updates all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (93 commits) timers: Make the cpu base lock raw clocksource/drivers/mips-gic-timer: Fix an error code in 'gic_clocksource_of_init()' clocksource/drivers/fsl_ftm_timer: Unmap region obtained by of_iomap clocksource/drivers/tcb_clksrc: Make IO endian agnostic clocksource/drivers/sun4i: Switch to the timer-of common init clocksource/drivers/timer-of: Fix invalid iomap check Revert "ktime: Simplify ktime_compare implementation" clocksource/drivers: Fix uninitialized variable use in timer_of_init kselftests: timers: Add test for frequency step kselftests: timers: Fix inconsistency-check to not ignore first timestamp time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD time: Clean up CLOCK_MONOTONIC_RAW time handling posix-cpu-timers: Make timespec to nsec conversion safe itimer: Make timeval to nsec conversion range limited timers: Fix parameter description of try_to_del_timer_sync() ktime: Simplify ktime_compare implementation clocksource/drivers/fttmr010: Factor out clock read code clocksource/drivers/fttmr010: Implement delay timer clocksource/drivers: Add timer-of common init routine clocksource/drivers/tcb_clksrc: Save timer context on suspend/resume ...
2017-06-14clocksource/drivers: Add an alias macro CLOCKSOURCE_OF_DECLAREDaniel Lezcano1-0/+3
The macro CLOCKSOURCE_OF_DECLARE has been rename to TIMER_OF_DECLARE. In order to prevent conflicts for the next merge window, a temporary alias has been added which will be removed later. Cc: Arnd Bergman <arnd@arndb.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2017-06-14clocksource/drivers: Rename CLKSRC_OF to TIMER_OFDaniel Lezcano1-1/+1
The config option name is now renamed to 'TIMER_OF' for consistency with the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-14clocksource/drivers: Rename clksrc table to timerDaniel Lezcano1-2/+2
The table name is now renamed to 'timer' for consistency with the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-14clocksource/drivers: Rename CLOCKSOURCE_ACPI_DECLARE to TIMER_ACPI_DECLAREDaniel Lezcano1-1/+1
The macro name is now renamed to 'TIMER_ACPI_DECLARE' for consistency with the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-14clocksource/drivers: Rename clocksource_probe to timer_probeDaniel Lezcano1-2/+2
The function name is now renamed to 'timer_probe' for consistency with the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-14clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLAREDaniel Lezcano1-1/+1
The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the clocksource at early stage. However, this macro is also used to initialize the clockevent if any, or the clockevent only. It was originally suggested to declare another macro to initialize a clockevent, so in order to separate the two entities even they belong to the same IP. This was not accepted because of the impact on the DT where splitting a clocksource/clockevent definition does not make sense as it is a Linux concept not a hardware description. On the other side, the clocksource has not interrupt declared while the clockevent has, so it is easy from the driver to know if the description is for a clockevent or a clocksource, IOW it could be implemented at the driver level. So instead of dealing with a named clocksource macro, let's use a more generic one: TIMER_OF_DECLARE. The patch has not functional changes. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Matthias Brugger <matthias.bgg@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-05-15x86/tsc, sched/clock, clocksource: Use clocksource watchdog to provide ↵Peter Zijlstra1-0/+1
stable sync points Currently we keep sched_clock_tick() active for stable TSC in order to keep the per-CPU state semi up-to-date. The (obvious) problem is that by the time we detect TSC is borked, our per-CPU state is also borked. So hook into the clocksource watchdog and call a method after we've found it to still be stable. There's the obvious race where the TSC goes wonky between finding it stable and us running the callback, but closing that is too much work and not really worth it, since we're already detecting TSC wobbles after the fact, so we cannot, per definition, fully avoid funny clock values. And since the watchdog runs less often than the tick, this is also an optimization. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-20clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASKMatthias Kaehlcke1-1/+1
Besides reusing existing code this removes the special case handling for 64-bit masks, which causes clang to raise a shift count overflow warning due to https://bugs.llvm.org//show_bug.cgi?id=10030. Suggested-by: Dmitry Torokhov <dtor@chromium.org> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: Grant Grundler <grundler@chromium.org> Cc: Greg Hackmann <ghackmann@google.com> Cc: Michael Davidson <md@google.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20170418233037.70990-1-mka@chromium.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-01-14sched/clock, clocksource: Add optional cs::mark_unstable() methodThomas Gleixner1-0/+3
PeterZ reported that we'd fail to mark the TSC unstable when the clocksource watchdog finds it unsuitable. Allow a clocksource to run a custom action when its being marked unstable and hook up the TSC unstable code. Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-25clocksource: Use a plain u64 instead of cycle_tThomas Gleixner1-11/+11
There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org>
2016-11-29timekeeping/clocksource_cyc2ns: Document intended range limitationChris Metcalf1-1/+4
The "cycles" argument should not be an absolute clocksource cycle value, as the implementation's arithmetic will overflow relatively easily with wide (64 bit) clocksource counters. For performance, the implementation is simple and fast, since the function is intended for only relatively small delta values of clocksource cycles. [jstultz: Fixed up to merge against HEAD & commit message tweaks, also included rewording suggestion by Ingo] Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Link: http://lkml.kernel.org/r/1480372524-15181-4-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-28clocksources: Switch back to the clksrc tableDaniel Lezcano1-4/+1
All the clocksource drivers's init function are now converted to return an error code. CLOCKSOURCE_OF_DECLARE is no longer used as well as the clksrc-of table. Let's convert back the names: - CLOCKSOURCE_OF_DECLARE_RET => CLOCKSOURCE_OF_DECLARE - clksrc-of-ret => clksrc-of Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> For exynos_mct and samsung_pwm_timer: Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> For arch/arc: Acked-by: Vineet Gupta <vgupta@synopsys.com> For mediatek driver: Acked-by: Matthias Brugger <matthias.bgg@gmail.com> For the Rockchip-part Acked-by: Heiko Stuebner <heiko@sntech.de> For STi : Acked-by: Patrice Chotard <patrice.chotard@st.com> For the mps2-timer.c and versatile.c changes: Acked-by: Liviu Dudau <Liviu.Dudau@arm.com> For the OXNAS part : Acked-by: Neil Armstrong <narmstrong@baylibre.com> For LPC32xx driver: Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com> For Broadcom Kona timer change: Acked-by: Ray Jui <ray.jui@broadcom.com> For Sun4i and Sun5i: Acked-by: Chen-Yu Tsai <wens@csie.org> For Meson6: Acked-by: Carlo Caione <carlo@caione.org> For Keystone: Acked-by: Santosh Shilimkar <ssantosh@kernel.org> For NPS: Acked-by: Noam Camus <noamca@mellanox.com> For bcm2835: Acked-by: Eric Anholt <eric@anholt.net>
2016-06-28clocksource/drivers/clksrc-probe: Introduce init functions with return codeDaniel Lezcano1-0/+3
Currently, the clksrc-probe is not able to handle any error from the init functions. There are different issues with the current code: - the code is duplicated in the init functions by writing error - every driver tends to panic in its own init function - counting the number of clocksources is not reliable This patch adds another table to store the functions returning an error. The table is temporary while we convert all the drivers to return an error and will disappear. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2016-04-22clocksource: Add missing include of of.h.David Lechner1-0/+1
This header uses OF_DELCARE_1 which is defined in linux/of.h. This fixes getting unhelpful compiler error messages about missing ')' before a string constant. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: David Lechner <david@lechnology.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-02-27clocksource: Introduce clocksource_freq2mult()Alexander Kuleshov1-26/+19
The clocksource_khz2mult() and clocksource_hz2mult() share similar code wihch calculates a mult from the given frequency. Both implementations in differ only in value of a frequency. This patch introduces the clocksource_freq2mult() helper with generic implementation of mult calculation to prevent code duplication. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Link: http://lkml.kernel.org/r/1456542854-22104-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-11-26timekeeping: Lift clocksource cacheline restrictionThomas Gleixner1-5/+11
We cache all hotpath members of a clocksource in the time keeper core. So there is no requirement in general to cache line align struct clocksource. Remove the enforces alignment. That allows users which need to wrap struct clocksource into their own struct to align the struct without getting extra padding. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Marc Gonzalez <marc_gonzalez@sigmadesigns.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Mans Rullgard <mans@mansr.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Tony Lindgren <tony@atomide.com> Cc: Sebastian Frias <sebastian_frias@sigmadesigns.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1511191209000.3898@nanos
2015-10-01clocksource: cosmetic: Drop OF 'dependency' from symbolsMarc Zyngier1-2/+2
Seeing the 'of' characters in a symbol that is being called from ACPI seems to freak out people. So let's do a bit of pointless renaming so that these folks do feel at home. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-01clocksource / arm_arch_timer: Convert to ACPI probingMarc Zyngier1-6/+0
It is now absolutely trivial to convert the arch timer driver to use ACPI probing, just like its DT counterpart. Let's enjoy another crapectomy. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-01clocksource: Add new CLKSRC_{PROBE,ACPI} config symbolsMarc Zyngier1-1/+1
The clocksource probing infrastructure currently depends on CONFIG_CLKSRC_OF, which depends on CONFIG_OF. In order to make this infrastructure selectable even if CONFIG_OF is not selected, introduce a new CONFIG_CLKSRC_PROBE (which allow the infrastructure to be compiled in), and CONFIG_CLKSRC_ACPI (which is the pendent of CONFIG_CLKSRC_OF for ACPI). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-01clocksource / ACPI: Add probing infrastructure for ACPI-based clocksourcesMarc Zyngier1-0/+3
DT enjoys a rather nice probing infrastructure for clocksources, while ACPI is so far stuck into a very distant past. This patch introduces a declarative API, allowing clocksources to be self-contained and be called when parsing the GTDT table. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-05-19Merge branch 'linus' into timers/coreThomas Gleixner1-0/+6
Make sure the upstream fixes are applied before adding further modifications.
2015-04-24Merge tag 'arm64-upstream' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull initial ACPI support for arm64 from Will Deacon: "This series introduces preliminary ACPI 5.1 support to the arm64 kernel using the "hardware reduced" profile. We don't support any peripherals yet, so it's fairly limited in scope: - MEMORY init (UEFI) - ACPI discovery (RSDP via UEFI) - CPU init (FADT) - GIC init (MADT) - SMP boot (MADT + PSCI) - ACPI Kconfig options (dependent on EXPERT) ACPI for arm64 has been in development for a while now and hardware has been available that can boot with either FDT or ACPI tables. This has been made possible by both changes to the ACPI spec to cater for ARM-based machines (known as "hardware-reduced" in ACPI parlance) but also a Linaro-driven effort to get this supported on top of the Linux kernel. This pull request is the result of that work. These changes allow us to initialise the CPUs, interrupt controller, and timers via ACPI tables, with memory information and cmdline coming from EFI. We don't support a hybrid ACPI/FDT scheme. Of course, there is still plenty of work to do (a serial console would be nice!) but I expect that to happen on a per-driver basis after this core series has been merged. Anyway, the diff stat here is fairly horrible, but splitting this up and merging it via all the different subsystems would have been extremely painful. Instead, we've got all the relevant Acks in place and I've not seen anything other than trivial (Kconfig) conflicts in -next (for completeness, I've included my resolution below). Nearly half of the insertions fall under Documentation/. So, we'll see how this goes. Right now, it all depends on EXPERT and I fully expect people to use FDT by default for the immediate future" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (31 commits) ARM64 / ACPI: make acpi_map_gic_cpu_interface() as void function ARM64 / ACPI: Ignore the return error value of acpi_map_gic_cpu_interface() ARM64 / ACPI: fix usage of acpi_map_gic_cpu_interface ARM64: kernel: acpi: honour acpi=force command line parameter ARM64: kernel: acpi: refactor ACPI tables init and checks ARM64: kernel: psci: let ACPI probe PSCI version ARM64: kernel: psci: factor out probe function ACPI: move arm64 GSI IRQ model to generic GSI IRQ layer ARM64 / ACPI: Don't unflatten device tree if acpi=force is passed ARM64 / ACPI: additions of ACPI documentation for arm64 Documentation: ACPI for ARM64 ARM64 / ACPI: Enable ARM64 in Kconfig XEN / ACPI: Make XEN ACPI depend on X86 ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 clocksource / arch_timer: Parse GTDT to initialize arch timer irqchip: Add GICv2 specific ACPI boot support ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi ACPI / processor: Make it possible to get CPU hardware ID via GICC ACPI / processor: Introduce phys_cpuid_t for CPU hardware ID ARM64 / ACPI: Parse MADT for SMP initialization ...
2015-04-22time: Remove nonexistent function prototypeYingjoe Chen1-1/+0
The function clocksource_get_next() was removed in commit 75c5158f70 (timekeeping: Update clocksource with stop_machine), but the prototype was not removed with it. Remove the prototype. Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com> Cc: <linux-arm-kernel@lists.infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <srv_heupstream@mediatek.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1428674150-1780-1-git-send-email-yingjoe.chen@mediatek.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-03-26clocksource / arch_timer: Parse GTDT to initialize arch timerHanjun Guo1-0/+6
Using the information presented by GTDT (Generic Timer Description Table) to initialize the arch timer (not memory-mapped). CC: Daniel Lezcano <daniel.lezcano@linaro.org> CC: Thomas Gleixner <tglx@linutronix.de> Originally-by: Amit Daniel Kachhap <amit.daniel@samsung.com> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> Tested-by: Yijing Wang <wangyijing@huawei.com> Tested-by: Mark Langsdorf <mlangsdo@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Tested-by: Timur Tabi <timur@codeaurora.org> Tested-by: Robert Richter <rrichter@cavium.com> Acked-by: Robert Richter <rrichter@cavium.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-13clocksource: Rename __clocksource_updatefreq_*() to ↵John Stultz1-5/+5
__clocksource_update_freq_*() Ingo requested this function be renamed to improve readability, so I've renamed __clocksource_updatefreq_scale() as well as the __clocksource_updatefreq_hz/khz() functions to avoid squishedtogethernames. This touches some of the sh clocksources, which I've not tested. The arch/arm/plat-omap change is just a comment change for consistency. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-13-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-13clocksource: Mostly kill clocksource_register()John Stultz1-1/+9
A long running project has been to clean up remaining uses of clocksource_register(), replacing it with the simpler clocksource_register_khz/hz() functions. However, there are a few cases where we need to self-define our mult/shift values, so switch the function to a more obviously internal __clocksource_register() name, and consolidate much of the internal logic so we don't have duplication. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-10-git-send-email-john.stultz@linaro.org [ Minor cleanups. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-12clocksource: Add 'max_cycles' to 'struct clocksource'John Stultz1-2/+3
In order to facilitate clocksource validation, add a 'max_cycles' field to the clocksource structure which will hold the maximum cycle value that can safely be multiplied without potentially causing an overflow. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-4-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-12-31time: move the timecounter/cyclecounter code into its own file.Richard Cochran1-102/+0
The timecounter code has almost nothing to do with the clocksource code. Let it live in its own file. This will help isolate the timecounter users from the clocksource users in the source tree. Signed-off-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-23clocksource: Remove "weak" from clocksource_default_clock() declarationBjorn Helgaas1-1/+1
kernel/time/jiffies.c provides a default clocksource_default_clock() definition explicitly marked "weak". arch/s390 provides its own definition intended to override the default, but the "weak" attribute on the declaration applied to the s390 definition as well, so the linker chose one based on link order (see 10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node decl")). Remove the "weak" attribute from the clocksource_default_clock() declaration so we always prefer a non-weak definition over the weak one, independent of link order. Fixes: f1b82746c1e9 ("clocksource: Cleanup clocksource selection") Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Ingo Molnar <mingo@kernel.org> CC: Daniel Lezcano <daniel.lezcano@linaro.org> CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-07-24clocksource: Get rid of cycle_lastThomas Gleixner1-2/+0
cycle_last was added to the clocksource to support the TSC validation. We moved that to the core code, so we can get rid of the extra copy. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-05-20of: consolidate linker section OF match table declarationsRob Herring1-13/+3
We now have several OF match tables using linker sections that are nearly the same definition. The only variation is the callback function prototype. Create a common define for creating linker section OF match table entries which each table declaration can use. Acked-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Rob Herring <robh@kernel.org>
2013-07-30clocksource: Extract max nsec calculation into separate functionStephen Boyd1-0/+2
We need to calculate the same number in the clocksource code and the sched_clock code, so extract this code into its own function. We also drop the min_t and just use min() because the two types are the same. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-07-05clocksource: Reselect clocksource when watchdog validated high-res capabilityThomas Gleixner1-0/+1
Up to commit 5d33b883a (clocksource: Always verify highres capability) we had no sanity check when selecting a clocksource, which prevented that a non highres capable clocksource is used when the system already switched to highres/nohz mode. The new sanity check works as Alex and Tim found out. It prevents the TSC from being used. This happens because on x86 the boot process looks like this: tsc_start_freqency_validation(TSC); clocksource_register(HPET); clocksource_done_booting(); clocksource_select() Selects HPET which is valid for high-res switch_to_highres(); clocksource_register(TSC); TSC is not selected, because it is not yet flagged as VALID_HIGH_RES clocksource_watchdog() Validates TSC for highres, but that does not make TSC the current clocksource. Before the sanity check was added, we installed TSC unvalidated which worked most of the time. If the TSC was really detected as unstable, then the unstable logic removed it and installed HPET again. The sanity check is correct and needed. So the watchdog needs to kick a reselection of the clocksource, when it qualifies TSC as a valid high res clocksource. To solve this, we mark the clocksource which got the flag CLOCK_SOURCE_VALID_FOR_HRES set by the watchdog with an new flag CLOCK_SOURCE_RESELECT and trigger the watchdog thread. The watchdog thread evaluates the flag and invokes clocksource_select() when set. To avoid that the clocksource_done_booting() code, which is about to install the first real clocksource anyway, needs to go through clocksource_select and tick_oneshot_notify() pointlessly, split out the clocksource_watchdog_kthread() list walk code and invoke the select/notify only when called from clocksource_watchdog_kthread(). So clocksource_done_booting() can utilize the same splitout code without the select/notify invocation and the clocksource_mutex unlock/relock dance. Reported-and-tested-by: Alex Shi <alex.shi@intel.com> Cc: Hans Peter Anvin <hpa@linux.intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <andi.kleen@intel.com> Tested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@kernel.org> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1307042239150.11637@ionos.tec.linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>