02 Nov, 2017

1 commit

  • 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
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

06 Dec, 2016

1 commit

  • The fixdep tool, among other things, replaces the target of the object
    in the gcc generated dependency output file.

    The parsing code assumes there's only single target in the rule but this
    is not always the case as described in here:

    https://gcc.gnu.org/ml/gcc-help/2016-11/msg00099.html

    Make the fixdep code smart enough to skip all the possible targets.

    Signed-off-by: Jiri Olsa
    Tested-by: Arnaldo Carvalho de Melo
    Acked-by: Peter Foley
    Cc: Wang Nan
    Link: http://lkml.kernel.org/r/20161201130025.GA16430@krava
    Signed-off-by: Arnaldo Carvalho de Melo

    Jiri Olsa
     

29 Sep, 2015

1 commit

  • For dependency tracking we currently use targets that fall out of the
    gcc -MD command. We store this info in the .cmd file and include as
    makefile during the build.

    This format put object as target and all the c and header files as
    dependencies, like:

    util/abspath.o: util/abspath.c /usr/include/stdc-predef.h util/cache.h \
    /usr/include/bits/wordsize.h /usr/include/gnu/stubs.h \
    ...

    If any of those dependency header files (krava.h below) is removed the
    build fails on:

    make[1]: *** No rule to make target 'krava.h', needed by 'inc.o'. Stop.

    This patch adds fixdep helper, that is used by kbuild to alter the shape
    of the object dependencies like:

    source_util/abspath.o := util/abspath.c

    deps_util/abspath.o := \
    /usr/include/stdc-predef.h \
    util/cache.h \
    ...

    util/abspath.o: $(deps_util/abspath.o)

    $(deps_util/abspath.o):

    With this format the header removal won't make the build fail, because
    it'll be picked up by the last empty target defined for each header.

    As previously mentioned the fixdep tool is taken from kbuild. It's not
    complete backport, only the part that alters the standard dependency
    info was taken, the part that adds the CONFIG_* dependency logic will be
    probably taken later on.

    Signed-off-by: Jiri Olsa
    Cc: David Ahern
    Cc: Kai Germaschewski
    Cc: Namhyung Kim
    Cc: Peter Zijlstra
    Link: http://lkml.kernel.org/r/1443004442-32660-4-git-send-email-jolsa@kernel.org
    Signed-off-by: Arnaldo Carvalho de Melo

    Jiri Olsa