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  1. Jul 15, 2024
  2. May 14, 2024
    • Masahiro Yamada's avatar
      Makefile: remove redundant tool coverage variables · 7f7f6f7a
      Masahiro Yamada authored
      
      Now Kbuild provides reasonable defaults for objtool, sanitizers, and
      profilers.
      
      Remove redundant variables.
      
      Note:
      
      This commit changes the coverage for some objects:
      
        - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
        - include arch/sparc/vdso/vdso-image-*.o into UBSAN
        - include arch/sparc/vdso/vma.o into UBSAN
        - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
        - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
        - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
        - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
        - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV
      
      I believe these are positive effects because all of them are kernel
      space objects.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Reviewed-by: default avatarKees Cook <keescook@chromium.org>
      Tested-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      7f7f6f7a
  3. May 09, 2024
    • Masahiro Yamada's avatar
      kbuild: use $(src) instead of $(srctree)/$(src) for source directory · b1992c37
      Masahiro Yamada authored
      
      Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
      checked-in source files. It is merely a convention without any functional
      difference. In fact, $(obj) and $(src) are exactly the same, as defined
      in scripts/Makefile.build:
      
          src := $(obj)
      
      When the kernel is built in a separate output directory, $(src) does
      not accurately reflect the source directory location. While Kbuild
      resolves this discrepancy by specifying VPATH=$(srctree) to search for
      source files, it does not cover all cases. For example, when adding a
      header search path for local headers, -I$(srctree)/$(src) is typically
      passed to the compiler.
      
      This introduces inconsistency between upstream and downstream Makefiles
      because $(src) is used instead of $(srctree)/$(src) for the latter.
      
      To address this inconsistency, this commit changes the semantics of
      $(src) so that it always points to the directory in the source tree.
      
      Going forward, the variables used in Makefiles will have the following
      meanings:
      
        $(obj)     - directory in the object tree
        $(src)     - directory in the source tree  (changed by this commit)
        $(objtree) - the top of the kernel object tree
        $(srctree) - the top of the kernel source tree
      
      Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
      with $(src).
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Reviewed-by: default avatarNicolas Schier <nicolas@fjasle.eu>
      b1992c37
  4. Oct 20, 2023
  5. Jun 25, 2023
  6. Jan 13, 2023
  7. Sep 28, 2022
    • Masahiro Yamada's avatar
      kbuild: generate include/generated/compile.h in top Makefile · a55f283e
      Masahiro Yamada authored
      
      Now that UTS_VERSION was separated out, this header can be generated
      much earlier, and probably the top Makefile is a better place to do it
      than init/Makefile.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      a55f283e
    • Masahiro Yamada's avatar
      kbuild: build init/built-in.a just once · 2df8220c
      Masahiro Yamada authored
      
      Kbuild builds init/built-in.a twice; first during the ordinary
      directory descending, second from scripts/link-vmlinux.sh.
      
      We do this because UTS_VERSION contains the build version and the
      timestamp. We cannot update it during the normal directory traversal
      since we do not yet know if we need to update vmlinux. UTS_VERSION is
      temporarily calculated, but omitted from the update check. Otherwise,
      vmlinux would be rebuilt every time.
      
      When Kbuild results in running link-vmlinux.sh, it increments the
      version number in the .version file and takes the timestamp at that
      time to really fix UTS_VERSION.
      
      However, updating the same file twice is a footgun. To avoid nasty
      timestamp issues, all build artifacts that depend on init/built-in.a
      are atomically generated in link-vmlinux.sh, where some of them do not
      need rebuilding.
      
      To fix this issue, this commit changes as follows:
      
      [1] Split UTS_VERSION out to include/generated/utsversion.h from
          include/generated/compile.h
      
          include/generated/utsversion.h is generated just before the
          vmlinux link. It is generated under include/generated/ because
          some decompressors (s390, x86) use UTS_VERSION.
      
      [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
          from init/version.c
      
          init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
          directory descending, they are compiled with __weak and used to
          determine if vmlinux needs relinking. Just before the vmlinux link,
          they are compiled without __weak to embed the real version and
          timestamp.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      2df8220c
  8. Mar 11, 2022
  9. Jan 08, 2022
    • Masahiro Yamada's avatar
      kbuild: do not quote string values in include/config/auto.conf · 129ab0d2
      Masahiro Yamada authored
      
      The previous commit fixed up all shell scripts to not include
      include/config/auto.conf.
      
      Now that include/config/auto.conf is only included by Makefiles,
      we can change it into a more Make-friendly form.
      
      Previously, Kconfig output string values enclosed with double-quotes
      (both in the .config and include/config/auto.conf):
      
          CONFIG_X="foo bar"
      
      Unlike shell, Make handles double-quotes (and single-quotes as well)
      verbatim. We must rip them off when used.
      
      There are some patterns:
      
        [1] $(patsubst "%",%,$(CONFIG_X))
        [2] $(CONFIG_X:"%"=%)
        [3] $(subst ",,$(CONFIG_X))
        [4] $(shell echo $(CONFIG_X))
      
      These are not only ugly, but also fragile.
      
      [1] and [2] do not work if the value contains spaces, like
         CONFIG_X=" foo bar "
      
      [3] does not work correctly if the value contains double-quotes like
         CONFIG_X="foo\"bar"
      
      [4] seems to work better, but has a cost of forking a process.
      
      Anyway, quoted strings were always PITA for our Makefiles.
      
      This commit changes Kconfig to stop quoting in include/config/auto.conf.
      
      These are the string type symbols referenced in Makefiles or scripts:
      
          ACPI_CUSTOM_DSDT_FILE
          ARC_BUILTIN_DTB_NAME
          ARC_TUNE_MCPU
          BUILTIN_DTB_SOURCE
          CC_IMPLICIT_FALLTHROUGH
          CC_VERSION_TEXT
          CFG80211_EXTRA_REGDB_KEYDIR
          EXTRA_FIRMWARE
          EXTRA_FIRMWARE_DIR
          EXTRA_TARGETS
          H8300_BUILTIN_DTB
          INITRAMFS_SOURCE
          LOCALVERSION
          MODULE_SIG_HASH
          MODULE_SIG_KEY
          NDS32_BUILTIN_DTB
          NIOS2_DTB_SOURCE
          OPENRISC_BUILTIN_DTB
          SOC_CANAAN_K210_DTB_SOURCE
          SYSTEM_BLACKLIST_HASH_LIST
          SYSTEM_REVOCATION_KEYS
          SYSTEM_TRUSTED_KEYS
          TARGET_CPU
          UNUSED_KSYMS_WHITELIST
          XILINX_MICROBLAZE0_FAMILY
          XILINX_MICROBLAZE0_HW_VER
          XTENSA_VARIANT_NAME
      
      I checked them one by one, and fixed up the code where necessary.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      129ab0d2
  10. Nov 11, 2021
    • Valentin Schneider's avatar
      preempt: Restore preemption model selection configs · a8b76910
      Valentin Schneider authored
      
      Commit c597bfdd ("sched: Provide Kconfig support for default dynamic
      preempt mode") changed the selectable config names for the preemption
      model. This means a config file must now select
      
        CONFIG_PREEMPT_BEHAVIOUR=y
      
      rather than
      
        CONFIG_PREEMPT=y
      
      to get a preemptible kernel. This means all arch config files would need to
      be updated - right now they'll all end up with the default
      CONFIG_PREEMPT_NONE_BEHAVIOUR.
      
      Rather than touch a good hundred of config files, restore usage of
      CONFIG_PREEMPT{_NONE, _VOLUNTARY}. Make them configure:
      o The build-time preemption model when !PREEMPT_DYNAMIC
      o The default boot-time preemption model when PREEMPT_DYNAMIC
      
      Add siblings of those configs with the _BUILD suffix to unconditionally
      designate the build-time preemption model (PREEMPT_DYNAMIC is built with
      the "highest" preemption model it supports, aka PREEMPT). Downstream
      configs should by now all be depending / selected by CONFIG_PREEMPTION
      rather than CONFIG_PREEMPT, so only a few sites need patching up.
      
      Signed-off-by: default avatarValentin Schneider <valentin.schneider@arm.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Acked-by: default avatarMarco Elver <elver@google.com>
      Link: https://lore.kernel.org/r/20211110202448.4054153-2-valentin.schneider@arm.com
      a8b76910
  11. May 26, 2021
  12. Jul 16, 2020
  13. May 12, 2020
  14. Apr 08, 2020
  15. Aug 13, 2019
  16. Jan 09, 2018
  17. Nov 02, 2017
    • 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
  18. Sep 09, 2016
    • Nicholas Piggin's avatar
      kbuild: allow archs to select link dead code/data elimination · b67067f1
      Nicholas Piggin authored
      
      Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to
      select to build with -ffunction-sections, -fdata-sections, and link
      with --gc-sections. It requires some work (documented) to ensure all
      unreferenced entrypoints are live, and requires toolchain and build
      verification, so it is made a per-arch option for now.
      
      On a random powerpc64le build, this yelds a significant size saving,
      it boots and runs fine, but there is a lot I haven't tested as yet, so
      these savings may be reduced if there are bugs in the link.
      
          text      data        bss        dec   filename
      11169741   1180744    1923176	14273661   vmlinux
      10445269   1004127    1919707	13369103   vmlinux.dce
      
      ~700K text, ~170K data, 6% removed from kernel image size.
      
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
      b67067f1
  19. May 05, 2012
    • Thomas Gleixner's avatar
      init_task: Replace CONFIG_HAVE_GENERIC_INIT_TASK · a6359d1e
      Thomas Gleixner authored
      
      Now that all archs except ia64 are converted, replace the config and
      let the ia64 select CONFIG_ARCH_INIT_TASK
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20120503085035.867948914@linutronix.de
      a6359d1e
    • Thomas Gleixner's avatar
      init_task: Create generic init_task instance · a4a2eb49
      Thomas Gleixner authored
      
      All archs define init_task in the same way (except ia64, but there is
      no particular reason why ia64 cannot use the common version). Create a
      generic instance so all archs can be converted over.
      
      The config switch is temporary and will be removed when all archs are
      converted over.
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Chen Liqin <liqin.chen@sunplusct.com>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: David Howells <dhowells@redhat.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
      Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
      Cc: Hirokazu Takata <takata@linux-m32r.org>
      Cc: James E.J. Bottomley <jejb@parisc-linux.org>
      Cc: Jesper Nilsson <jesper.nilsson@axis.com>
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Michal Simek <monstr@monstr.eu>
      Cc: Mike Frysinger <vapier@gentoo.org>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Link: http://lkml.kernel.org/r/20120503085034.092585287@linutronix.de
      a4a2eb49
  20. Dec 12, 2009
  21. Oct 16, 2008
  22. Feb 11, 2008
  23. Feb 09, 2008
  24. Oct 14, 2007
    • Sam Ravnborg's avatar
      kbuild: enable 'make CFLAGS=...' to add additional options to CC · a0f97e06
      Sam Ravnborg authored
      
      The variable CFLAGS is a wellknown variable and the usage by
      kbuild may result in unexpected behaviour.
      On top of that several people over time has asked for a way to
      pass in additional flags to gcc.
      
      This patch replace use of CFLAGS with KBUILD_CFLAGS all over the
      tree and enabling one to use:
      make CFLAGS=...
      to specify additional gcc commandline options.
      
      One usecase is when trying to find gcc bugs but other
      use cases has been requested too.
      
      Patch was tested on following architectures:
      alpha, arm, i386, x86_64, mips, sparc, sparc64, ia64, m68k
      
      Test was simple to do a defconfig build, apply the patch and check
      that nothing got rebuild.
      
      Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
      a0f97e06
  25. Feb 11, 2007
    • Jean-Paul Saman's avatar
      [PATCH] disable init/initramfs.c · c33df4ea
      Jean-Paul Saman authored
      
      The file init/initramfs.c is always compiled and linked in the kernel
      vmlinux even when BLK_DEV_RAM and BLK_DEV_INITRD are disabled and the
      system isn't using any form of an initramfs or initrd.  In this situation
      the code is only used to unpack a (static) default initial rootfilesystem.
      The current init/initramfs.c code.  usr/initramfs_data.o compiles to a size
      of ~15 kbytes.  Disabling BLK_DEV_RAM and BLK_DEV_INTRD shrinks the kernel
      code size with ~60 Kbytes.
      
      This patch avoids compiling in the code and data for initramfs support if
      CONFIG_BLK_DEV_INITRD is not defined.  Instead of the initramfs code and
      data it uses a small routine in init/noinitramfs.c to setup an initial
      static default environment for mounting a rootfilesystem later on in the
      kernel initialisation process.  The new code is: 164 bytes of size.
      
      The patch is separated in two parts:
      1) doesn't compile initramfs code when CONFIG_BLK_DEV_INITRD is not set
      2) changing all plaforms vmlinux.lds.S files to not reserve an area of
      PAGE_SIZE when CONFIG_BLK_DEV_INITRD is not set.
      
      [deweerdt@free.fr: warning fix]
      Signed-off-by: default avatarJean-Paul Saman <jean-paul.saman@nxp.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: <linux-arch@vger.kernel.org>
      Signed-off-by: default avatarFrederik Deweerdt <frederik.deweerdt@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c33df4ea
  26. Jan 10, 2007
  27. Dec 22, 2006
    • Andrew Morton's avatar
      [PATCH] build compile.h earlier · ef129412
      Andrew Morton authored
      
      compile.h is created super-late in the build.  But proc_misc.c want to include
      it, and it's generally not sane to have a header file in include/linux be
      created at the end of the build: it's either not present or, worse, wrong for
      most of the build.
      
      So the patch arranges for compile.h to be built at the start of the build
      process.  It also consolidates the compile.h rules with those for version.h
      and utsname.h, so they all get built together.
      
      I hope.  My chances of having got this right are about 2%.
      
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      ef129412
  28. Dec 08, 2006
  29. Jun 26, 2006
  30. Jul 14, 2005
  31. Apr 16, 2005
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      
      Let it rip!
      1da177e4
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