1. 04 Oct, 2018 1 commit
  2. 03 Oct, 2018 1 commit
  3. 20 Jul, 2018 1 commit
    • Baolin Wang's avatar
      time: Introduce one suspend clocksource to compensate the suspend time · 39232ed5
      Baolin Wang authored
      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: default avatarThomas Gleixner <tglx@linutronix.de>
      Reviewed-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarBaolin Wang <baolin.wang@linaro.org>
      [jstultz: minor tweaks to merge with previous resume changes]
      Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      39232ed5
  4. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      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: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  5. 14 Jun, 2017 6 commits
  6. 15 May, 2017 1 commit
    • Peter Zijlstra's avatar
      x86/tsc, sched/clock, clocksource: Use clocksource watchdog to provide stable sync points · b421b22b
      Peter Zijlstra authored
      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: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
      b421b22b
  7. 20 Apr, 2017 1 commit
  8. 14 Jan, 2017 1 commit
  9. 25 Dec, 2016 1 commit
  10. 29 Nov, 2016 1 commit
  11. 28 Jun, 2016 2 commits
  12. 22 Apr, 2016 1 commit
  13. 27 Feb, 2016 1 commit
  14. 25 Nov, 2015 1 commit
    • Thomas Gleixner's avatar
      timekeeping: Lift clocksource cacheline restriction · 09a99820
      Thomas Gleixner authored
      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: default avatarThomas 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
      09a99820
  15. 01 Oct, 2015 4 commits
  16. 22 Apr, 2015 1 commit
  17. 26 Mar, 2015 1 commit
  18. 13 Mar, 2015 2 commits
  19. 12 Mar, 2015 1 commit
  20. 30 Dec, 2014 1 commit
  21. 22 Oct, 2014 1 commit
    • Bjorn Helgaas's avatar
      clocksource: Remove "weak" from clocksource_default_clock() declaration · 96a2adbc
      Bjorn Helgaas authored
      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 10629d71 ("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: f1b82746 ("clocksource: Cleanup clocksource selection")
      Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
      Acked-by: default avatarJohn Stultz <john.stultz@linaro.org>
      Acked-by: default avatarIngo Molnar <mingo@kernel.org>
      CC: Daniel Lezcano <daniel.lezcano@linaro.org>
      CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
      96a2adbc
  22. 23 Jul, 2014 1 commit
  23. 20 May, 2014 1 commit
  24. 30 Jul, 2013 1 commit
  25. 05 Jul, 2013 1 commit
    • Thomas Gleixner's avatar
      clocksource: Reselect clocksource when watchdog validated high-res capability · 332962f2
      Thomas Gleixner authored
      Up to commit 5d33b883 (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: default avatarAlex 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: default avatarPeter 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.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      332962f2
  26. 16 May, 2013 3 commits
  27. 28 Mar, 2013 1 commit
  28. 19 Mar, 2013 1 commit