1. 18 Nov, 2017 1 commit
    • Sandipan Das's avatar
      include/linux/compiler-clang.h: handle randomizable anonymous structs · 4ca59b14
      Sandipan Das authored
      The GCC randomize layout plugin can randomize the member offsets of
      sensitive kernel data structures.  To use this feature, certain
      annotations and members are added to the structures which affect the
      member offsets even if this plugin is not used.
      
      All of these structures are completely randomized, except for task_struct
      which leaves out some of its members.  All the other members are wrapped
      within an anonymous struct with the __randomize_layout attribute.  This is
      done using the randomized_struct_fields_start and
      randomized_struct_fields_end defines.
      
      When the plugin is disabled, the behaviour of this attribute can vary
      based on the GCC version.  For GCC 5.1+, this attribute maps to
      __designated_init otherwise it is just an empty define but the anonymous
      structure is still present.  For other compilers, both
      randomized_struct_fields_start and randomized_struct_fields_end default
      to empty defines meaning the anonymous structure is not introduced at
      all.
      
      So, if a module compiled with Clang, such as a BPF program, needs to
      access task_struct fields such as pid and comm, the offsets of these
      members as recognized by Clang are different from those recognized by
      modules compiled with GCC.  If GCC 4.6+ is used to build the kernel,
      this can be solved by introducing appropriate defines for Clang so that
      the anonymous structure is seen when determining the offsets for the
      members.
      
      Link: http://lkml.kernel.org/r/20171109064645.25581-1-sandipan@linux.vnet.ibm.com
      
      
      Signed-off-by: default avatarSandipan Das <sandipan@linux.vnet.ibm.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Kate Stewart <kstewart@linuxfoundation.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
      Cc: Alexei Starovoitov <ast@fb.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4ca59b14
  2. 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
  3. 24 Oct, 2017 1 commit
    • Will Deacon's avatar
      linux/compiler.h: Split into compiler.h and compiler_types.h · d1515582
      Will Deacon authored
      
      
      linux/compiler.h is included indirectly by linux/types.h via
      uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h
      -> uapi/linux/stddef.h and is needed to provide a proper definition of
      offsetof.
      
      Unfortunately, compiler.h requires a definition of
      smp_read_barrier_depends() for defining lockless_dereference() and soon
      for defining READ_ONCE(), which means that all
      users of READ_ONCE() will need to include asm/barrier.h to avoid splats
      such as:
      
         In file included from include/uapi/linux/stddef.h:1:0,
                          from include/linux/stddef.h:4,
                          from arch/h8300/kernel/asm-offsets.c:11:
         include/linux/list.h: In function 'list_empty':
      >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration]
           smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \
           ^
      
      A better alternative is to include asm/barrier.h in linux/compiler.h,
      but this requires a type definition for "bool" on some architectures
      (e.g. x86), which is defined later by linux/types.h. Type "bool" is also
      used directly in linux/compiler.h, so the whole thing is pretty fragile.
      
      This patch splits compiler.h in two: compiler_types.h contains type
      annotations, definitions and the compiler-specific parts, whereas
      compiler.h #includes compiler-types.h and additionally defines macros
      such as {READ,WRITE.ACCESS}_ONCE().
      
      uapi/linux/stddef.h and linux/linkage.h are then moved over to include
      linux/compiler_types.h, which fixes the build for h8 and blackfin.
      
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com
      
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      d1515582
  4. 06 Jul, 2017 1 commit
  5. 11 Jun, 2017 1 commit
  6. 06 Jun, 2017 1 commit
  7. 08 Feb, 2016 1 commit
    • Arnd Bergmann's avatar
      Kbuild: provide a __UNIQUE_ID for clang · b41c29b0
      Arnd Bergmann authored
      
      
      The default __UNIQUE_ID macro in compiler.h fails to work for some drivers:
      
      drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:615:1: error: redefinition of
            '__UNIQUE_ID_firmware615'
      BRCMF_FW_NVRAM_DEF(4354, "brcmfmac4354-sdio.bin", "brcmfmac4354-sdio.txt");
      
      This adds a copy of the version we use for gcc-4.3 and higher, as the same
      one works with all versions of clang that I could find in svn (2.6 and higher).
      
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
      b41c29b0
  8. 09 Apr, 2014 1 commit