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
     

12 Jan, 2017

1 commit

  • Modules that use static_key_deferred need a way to synchronize with
    any delayed work that is still pending when the module is unloaded.
    Introduce static_key_deferred_flush() which flushes any pending
    jump label updates.

    Signed-off-by: David Matlack
    Cc: stable@vger.kernel.org
    Acked-by: Peter Zijlstra (Intel)
    Signed-off-by: Paolo Bonzini

    David Matlack
     

20 Oct, 2013

1 commit

  • Usage of the static key primitives to toggle a branch must not be used
    before jump_label_init() is called from init/main.c. jump_label_init
    reorganizes and wires up the jump_entries so usage before that could
    have unforeseen consequences.

    Following primitives are now checked for correct use:
    * static_key_slow_inc
    * static_key_slow_dec
    * static_key_slow_dec_deferred
    * jump_label_rate_limit

    The x86 architecture already checks this by testing if the default_nop
    was already replaced with an optimal nop or with a branch instruction. It
    will panic then. Other architectures don't check for this.

    Because we need to relax this check for the x86 arch to allow code to
    transition from default_nop to the enabled state and other architectures
    did not check for this at all this patch introduces checking on the
    static_key primitives in a non-arch dependent manner.

    All checked functions are considered slow-path so the additional check
    does no harm to performance.

    The warnings are best observed with earlyprintk.

    Based on a patch from Andi Kleen.

    Cc: Steven Rostedt
    Cc: Peter Zijlstra
    Cc: Andi Kleen
    Signed-off-by: Hannes Frederic Sowa
    Signed-off-by: David S. Miller

    Hannes Frederic Sowa
     

09 Aug, 2013

1 commit

  • Commit b202952075f62603bea9bfb6ebc6b0420db11949 ("perf, core: Rate limit
    perf_sched_events jump_label patching") introduced rate limiting
    for jump label disabling. The changes were made in the jump label code
    in order to be more widely available and to keep things tidier. This is
    all fine, except now jump_label.h includes linux/workqueue.h, which
    makes it impossible to include jump_label.h from anything that
    workqueue.h needs. For example, it's now impossible to include
    jump_label.h from asm/spinlock.h, which is done in proposed
    pv-ticketlock patches. This patch splits out the rate limiting related
    changes from jump_label.h into a new file, jump_label_ratelimit.h, to
    resolve the issue.

    Signed-off-by: Andrew Jones
    Link: http://lkml.kernel.org/r/1376058122-8248-10-git-send-email-raghavendra.kt@linux.vnet.ibm.com
    Reviewed-by: Konrad Rzeszutek Wilk
    Signed-off-by: Raghavendra K T
    Acked-by: Ingo Molnar
    Signed-off-by: H. Peter Anvin

    Andrew Jones