1. 15 5月, 2019 1 次提交
  2. 02 6月, 2018 1 次提交
  3. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman 提交于
      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: NKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  4. 12 5月, 2017 1 次提交
    • L
      tools/power x86_energy_perf_policy: support HWP.EPP · 4beec1d7
      Len Brown 提交于
      x86_energy_perf_policy(8) was created as an example
      of how the user, or upper-level OS, can manage
      MSR_IA32_ENERGY_PERF_BIAS (EPB).
      
      Hardware consults EPB when it makes internal decisions
      balancing energy-saving vs performance.
      For example, should HW quickly or slowly
      transition into and out of power-saving idles states?
      Should HW quickly or slowly ramp frequency up or down
      in response to demand in the turbo-frequency range?
      
      Depending on the processor, EPB may have package, core,
      or CPU thread scope.  As such, the only general policy
      is to write the same value to EPB on every CPU in the system.
      
      Recent platforms add support for Hardware Performance States (HWP).
      HWP effectively extends hardware frequency control from
      the opportunistic turbo-frequency range to control the entire
      range of available processor frequencies.
      
      Just as turbo-mode used EPB, HWP can use EPB to help decicde
      how quickly to ramp frequency and voltage up and down
      in response to changing demand.  Indeed, BDX and BDX-DE,
      the first processors to support HWP, use EPB for this purpose.
      
      Starting in SKL, HWP no longer looks to EPB for influence.
      Instead, it looks in a new MSR specifically for this purpose:
      IA32_HWP_REQUEST.Energy_Performance_Preference (HWP.EPP).
      HWP.EPP is like EPB, except that it is specific to HWP-mode
      frequency selection.  Also, HWP.EPP is defined to have
      per CPU-thread scope.
      
      Starting in SKX, IA32_HWP_REQUEST is augmented by
      IA32_HWP_REQUEST_PKG -- which has the same function, but is
      defined to have package-wide scope.  A new bit in IA32_HWP_REQUEST
      determines if it over-rides the IA32_HWP_REQUEST_PKG or not.
      
      Note that HWP-mode can be enabled in several ways.
      The "in-band" method is for HWP to be exposed in CPUID,
      and for the Linux intel_pstate driver to recognized that,
      and thus enable HWP.  In this case, starting in Linux 4.10, intel_pstate
      exports cpufreq sysfs attribute "energy_performance_preference"
      which can be used to manage HWP.EPP.  This interface can be
      used to set HWP.EPP to these values:
      
      0 performance
      128 balance_performance (default)
      192 balance_power
      255 power
      
      Here, x86_energy_performance_policy is updated to use
      idential strings and values as intel_pstate.
      
      But HWP-mode may also be enabled by firmware before the OS boots,
      and the OS may not be aware of HWP.  In this case, intel_pstate
      is not available to provide sysfs attributes, and x86_energy_perf_policy
      or a similar utility is invaluable for managing HWP.EPP, for
      this utility works the same, no matter if cpufreq is enabled or not.
      Signed-off-by: NLen Brown <len.brown@intel.com>
      4beec1d7
  5. 30 11月, 2012 1 次提交
  6. 12 1月, 2011 1 次提交
    • L
      tools: create power/x86/x86_energy_perf_policy · d5532ee7
      Len Brown 提交于
      MSR_IA32_ENERGY_PERF_BIAS first became available on Westmere Xeon.
      It is implemented in all Sandy Bridge processors -- mobile, desktop and server.
      It is expected to become increasingly important in subsequent generations.
      
      x86_energy_perf_policy is a user-space utility to set the
      hardware energy vs performance policy hint in the processor.
      Most systems would benefit from "x86_energy_perf_policy normal"
      at system startup, as the hardware default is maximum performance
      at the expense of energy efficiency.
      
      See x86_energy_perf_policy.8 man page for more information.
      
      Background:
      
      Linux-2.6.36 added "epb" to /proc/cpuinfo to indicate
      if an x86 processor supports MSR_IA32_ENERGY_PERF_BIAS,
      without actually modifying the MSR.
      
      In March, 2010, Venkatesh Pallipadi proposed a small driver
      that programmed MSR_IA32_ENERGY_PERF_BIAS, based on
      the cpufreq governor in use.  It also offered
      a boot-time cmdline option to override.
      http://lkml.org/lkml/2010/3/4/457
      But hiding the hardware policy behind the
      governor choice was deemed "kinda icky".
      
      In June, 2010, I proposed a generic user/kernel API to
      generalize the power/performance policy trade-off.
      "RFC: /sys/power/policy_preference"
      http://lkml.org/lkml/2010/6/16/399
      That is my preference for implementing this capability,
      but I received no support on the list.
      
      So in September, 2010, I sent x86_energy_perf_policy.c to LKML,
      a user-space utility that scribbles directly to the MSR.
      http://lkml.org/lkml/2010/9/28/246
      
      Here is that same utility, after responding to some review feedback,
      to live in tools/power/, where it is easily found.
      Signed-off-by: NLen Brown <len.brown@intel.com>
      d5532ee7