Commit Graph

336 Commits

Author SHA1 Message Date
Nick Desaulniers a0a12c3ed0 asm goto: eradicate CC_HAS_ASM_GOTO
GCC has supported asm goto since 4.5, and Clang has since version 9.0.0.
The minimum supported versions of these tools for the build according to
Documentation/process/changes.rst are 5.1 and 11.0.0 respectively.

Remove the feature detection script, Kconfig option, and clean up some
fallback code that is no longer supported.

The removed script was also testing for a GCC specific bug that was
fixed in the 4.7 release.

Also remove workarounds for bpftrace using clang older than 9.0.0, since
other BPF backend fixes are required at this point.

Link: https://lore.kernel.org/lkml/CAK7LNATSr=BXKfkdW8f-H5VT_w=xBpT2ZQcZ7rm6JfkdE+QnmA@mail.gmail.com/
Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637
Acked-by: Borislav Petkov <bp@suse.de>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-08-21 10:06:28 -07:00
Baruch Siach 59316eac0e docs: kbuild: fix typo
on -> one.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-07-27 21:18:00 +09:00
Nick Desaulniers 291810be42 Documentation/llvm: Update Supported Arch table
While watching Michael's new talk on Clang-built-Linux, I noticed the
arch table in our docs that he refers to is outdated.

Add hexagon and User Mode.  Bump MIPS and RISCV to LLVM=1.  PowerPC is
almost LLVM=1 capable; ppc64le works, but ppc64 (big endian) and ppc32
still need more work.

Link: https://youtu.be/W4zdEDpvR5c?t=399
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-06-20 08:21:29 +09:00
Linus Torvalds df202b452f Kbuild updates for v5.19
- Add HOSTPKG_CONFIG env variable to allow users to override pkg-config
 
  - Support W=e as a shorthand for KCFLAGS=-Werror
 
  - Fix CONFIG_IKHEADERS build to support toybox cpio
 
  - Add scripts/dummy-tools/pahole to ease distro packagers' life
 
  - Suppress false-positive warnings from checksyscalls.sh for W=2 build
 
  - Factor out the common code of arch/*/boot/install.sh into
    scripts/install.sh
 
  - Support 'kernel-install' tool in scripts/prune-kernel
 
  - Refactor module-versioning to link the symbol versions at the final
    link of vmlinux and modules
 
  - Remove CONFIG_MODULE_REL_CRCS because module-versioning now works in
    an arch-agnostic way
 
  - Refactor modpost, Makefiles
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Merge tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add HOSTPKG_CONFIG env variable to allow users to override pkg-config

 - Support W=e as a shorthand for KCFLAGS=-Werror

 - Fix CONFIG_IKHEADERS build to support toybox cpio

 - Add scripts/dummy-tools/pahole to ease distro packagers' life

 - Suppress false-positive warnings from checksyscalls.sh for W=2 build

 - Factor out the common code of arch/*/boot/install.sh into
   scripts/install.sh

 - Support 'kernel-install' tool in scripts/prune-kernel

 - Refactor module-versioning to link the symbol versions at the final
   link of vmlinux and modules

 - Remove CONFIG_MODULE_REL_CRCS because module-versioning now works in
   an arch-agnostic way

 - Refactor modpost, Makefiles

* tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (56 commits)
  genksyms: adjust the output format to modpost
  kbuild: stop merging *.symversions
  kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS
  modpost: extract symbol versions from *.cmd files
  modpost: add sym_find_with_module() helper
  modpost: change the license of EXPORT_SYMBOL to bool type
  modpost: remove left-over cross_compile declaration
  kbuild: record symbol versions in *.cmd files
  kbuild: generate a list of objects in vmlinux
  modpost: move *.mod.c generation to write_mod_c_files()
  modpost: merge add_{intree_flag,retpoline,staging_flag} to add_header
  scripts/prune-kernel: Use kernel-install if available
  kbuild: factor out the common installation code into scripts/install.sh
  modpost: split new_symbol() to symbol allocation and hash table addition
  modpost: make sym_add_exported() always allocate a new symbol
  modpost: make multiple export error
  modpost: dump Module.symvers in the same order of modules.order
  modpost: traverse the namespace_list in order
  modpost: use doubly linked list for dump_lists
  modpost: traverse unresolved symbols in order
  ...
2022-05-26 12:09:50 -07:00
Kees Cook be2b34fa9b randstruct: Move seed generation into scripts/basic/
To enable Clang randstruct support, move the structure layout
randomization seed generation out of scripts/gcc-plugins/ into
scripts/basic/ so it happens early enough that it can be used by either
compiler implementation. The gcc-plugin still builds its own header file,
but now does so from the common "randstruct.seed" file.

Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-6-keescook@chromium.org
2022-05-08 01:33:07 -07:00
Kees Cook 595b893e20 randstruct: Reorganize Kconfigs and attribute macros
In preparation for Clang supporting randstruct, reorganize the Kconfigs,
move the attribute macros, and generalize the feature to be named
CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full
randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line
sized mode.

Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
2022-05-08 01:33:06 -07:00
Necip Fazil Yildiran cab802b7b8 docs: kbuild: add references on Kconfig semantics
Add references to 1) a research paper which provides a definition of
Kconfig semantics, 2) the kismet tool, which checks for unmet direct
dependency bugs in Kconfig specifications.

Signed-off-by: Paul Gazzillo <paul@pgazz.com>
Signed-off-by: Necip Fazil Yildiran <fazilyildiran@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-04-06 19:27:41 +09:00
Nathan Chancellor e9c281928c kbuild: Make $(LLVM) more flexible
The LLVM make variable allows a developer to quickly switch between the
GNU and LLVM tools. However, it does not handle versioned binaries, such
as the ones shipped by Debian, as LLVM=1 just defines the tool variables
with the unversioned binaries.

There was some discussion during the review of the patch that introduces
LLVM=1 around versioned binaries, ultimately coming to the conclusion
that developers can just add the folder that contains the unversioned
binaries to their PATH, as Debian's versioned suffixed binaries are
really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin:

$ realpath /usr/bin/clang-14
/usr/lib/llvm-14/bin/clang

$ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1

However, that can be cumbersome to developers who are constantly testing
series with different toolchains and versions. It is simple enough to
support these versioned binaries directly in the Kbuild system by
allowing the developer to specify the version suffix with LLVM=, which
is shorter than the above suggestion:

$ make ... LLVM=-14

It does not change the meaning of LLVM=1 (which will continue to use
unversioned binaries) and it does not add too much additional complexity
to the existing $(LLVM) code, while allowing developers to quickly test
their series with different versions of the whole LLVM suite of tools.

Some developers may build LLVM from source but not add the binaries to
their PATH, as they may not want to use that toolchain systemwide.
Support those developers by allowing them to supply the directory that
the LLVM tools are available in, as it is no more complex to support
than the version suffix change above.

$ make ... LLVM=/path/to/llvm/

Update and reorder the documentation to reflect these new additions.
At the same time, notate that LLVM=0 is not the same as just omitting it
altogether, which has confused people in the past.

Link: https://lore.kernel.org/r/20200317215515.226917-1-ndesaulniers@google.com/
Link: https://lore.kernel.org/r/20220224151322.072632223@infradead.org/
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-03-31 12:03:46 +09:00
Elliot Berman f67695c996 kbuild: Add environment variables for userprogs flags
Allow additional arguments be passed to userprogs compilation.
Reproducible clang builds need to provide a sysroot and gcc path to
ensure the same toolchain is used across hosts. KCFLAGS is not currently
used for any user programs compilation, so add new USERCFLAGS and
USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS.

Clang might detect GCC installation on hosts which have it installed
to a default location in /. With addition of these environment
variables, you can specify flags such as:

$ make USERCFLAGS=--sysroot=/path/to/sysroot

This can also be used to specify different sysroots such as musl or
bionic which may be installed on the host in paths that the compiler
may not search by default.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-02-14 10:37:32 +09:00
Miguel Ojeda c199d5d0a7 doc: kbuild: fix default in `imply` table
`BAZ` takes `FOO`'s value as default (as far as `BAR` allows it).

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-01-08 18:28:21 +09:00
Linus Torvalds 1e9ed9360f Kbuild updates for v5.16
- Remove the global -isystem compiler flag, which was made possible by
    the introduction of <linux/stdarg.h>
 
  - Improve the Kconfig help to print the location in the top menu level
 
  - Fix "FORCE prerequisite is missing" build warning for sparc
 
  - Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which generate
    a zstd-compressed tarball
 
  - Prevent gen_init_cpio tool from generating a corrupted cpio when
    KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later
 
  - Misc cleanups
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Merge tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Remove the global -isystem compiler flag, which was made possible by
   the introduction of <linux/stdarg.h>

 - Improve the Kconfig help to print the location in the top menu level

 - Fix "FORCE prerequisite is missing" build warning for sparc

 - Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which
   generate a zstd-compressed tarball

 - Prevent gen_init_cpio tool from generating a corrupted cpio when
   KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later

 - Misc cleanups

* tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
  kbuild: use more subdir- for visiting subdirectories while cleaning
  sh: remove meaningless archclean line
  initramfs: Check timestamp to prevent broken cpio archive
  kbuild: split DEBUG_CFLAGS out to scripts/Makefile.debug
  gen_init_cpio: add static const qualifiers
  kbuild: Add make tarzst-pkg build option
  scripts: update the comments of kallsyms support
  sparc: Add missing "FORCE" target when using if_changed
  kconfig: refactor conf_touch_dep()
  kconfig: refactor conf_write_dep()
  kconfig: refactor conf_write_autoconf()
  kconfig: add conf_get_autoheader_name()
  kconfig: move sym_escape_string_value() to confdata.c
  kconfig: refactor listnewconfig code
  kconfig: refactor conf_write_symbol()
  kconfig: refactor conf_write_heading()
  kconfig: remove 'const' from the return type of sym_escape_string_value()
  kconfig: rename a variable in the lexer to a clearer name
  kconfig: narrow the scope of variables in the lexer
  kconfig: Create links to main menu items in search
  ...
2021-11-08 09:15:45 -08:00
Linus Torvalds 624ad333d4 This is a relatively unexciting cycle for documentation.
- Some small scripts/kerneldoc fixes
 
  - More Chinese translation work, but at a much reduced rate.
 
  - The tip-tree maintainer's handbook
 
 ...plus the usual array of build fixes, typo fixes, etc.
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Merge tag 'docs-5.16' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "This is a relatively unexciting cycle for documentation.

   - Some small scripts/kerneldoc fixes

   - More Chinese translation work, but at a much reduced rate.

   - The tip-tree maintainer's handbook

  ...plus the usual array of build fixes, typo fixes, etc"

* tag 'docs-5.16' of git://git.lwn.net/linux: (53 commits)
  kernel-doc: support DECLARE_PHY_INTERFACE_MASK()
  docs/zh_CN: add core-api xarray translation
  docs/zh_CN: add core-api assoc_array translation
  speakup: Fix typo in documentation "boo" -> "boot"
  docs: submitting-patches: make section about the Link: tag more explicit
  docs: deprecated.rst: Clarify open-coded arithmetic with literals
  scripts: documentation-file-ref-check: fix bpf selftests path
  scripts: documentation-file-ref-check: ignore hidden files
  coding-style.rst: trivial: fix location of driver model macros
  docs: f2fs: fix text alignment
  docs/zh_CN add PCI pci.rst translation
  docs/zh_CN add PCI index.rst translation
  docs: translations: zh_CN: memory-hotplug.rst: fix a typo
  docs: translations: zn_CN: irq-affinity.rst: add a missing extension
  block: add documentation for inflight
  scripts: kernel-doc: Ignore __alloc_size() attribute
  docs: pdfdocs: Adjust \headheight for fancyhdr
  docs: UML: user_mode_linux_howto_v2 edits
  docs: use the lore redirector everywhere
  docs: proc.rst: mountinfo: align columns
  ...
2021-11-02 22:11:39 -07:00
Masahiro Yamada 8212f8986d kbuild: use more subdir- for visiting subdirectories while cleaning
Documentation/kbuild/makefiles.rst suggests to use "archclean" for
cleaning arch/$(SRCARCH)/boot/, but it is not a hard requirement.

Since commit d92cc4d516 ("kbuild: require all architectures to have
arch/$(SRCARCH)/Kbuild"), we can use the "subdir- += boot" trick for
all architectures. This can take advantage of the parallel option (-j)
for "make clean".

I also cleaned up the comments in arch/$(SRCARCH)/Makefile. The "archdep"
target no longer exists.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
2021-10-24 13:49:46 +09:00
Kees Cook b4d89579cc gcc-plugins: Remove cyc_complexity
This plugin has no impact on the resulting binary, is disabled
under COMPILE_TEST, and is not enabled on any builds I'm aware of.
Additionally, given the clarified purpose of GCC plugins in the kernel,
remove cyc_complexity.

Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-hardening@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20211020173554.38122-3-keescook@chromium.org
2021-10-21 08:41:47 -07:00
Kees Cook 8bd51a2ba3 gcc-plugins: Explicitly document purpose and deprecation schedule
GCC plugins should only exist when some compiler feature needs to be
proven but does not exist in either GCC nor Clang. For example, if a
desired feature is already in Clang, it should be added to GCC upstream.
Document this explicitly.

Additionally, mark the plugins with matching upstream GCC features as
removable past their respective GCC versions.

Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: linux-hardening@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20211020173554.38122-2-keescook@chromium.org
2021-10-21 08:41:38 -07:00
Thorsten Leemhuis a9d85efb25 docs: use the lore redirector everywhere
Change all links from using the lkml redirector to the lore redirector,
as the kernel.org admin recently indicated: we shouldn't be using
lkml.kernel.org anymore because the domain can create confusion, as it
indicates it is only valid for messages sent to the LKML; the convention
has been to use https://lore.kernel.org/r/msgid for this reason.

In this process also change three links from using http to https.

Link: https://lore.kernel.org/r/20211006170025.qw3glxvocczfuhar@meerkat.local
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: Hu Haowen <src.res@email.cn>
CC: Alex Shi <alexs@kernel.org>
CC: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Link: https://lore.kernel.org/r/5bb55bac6ba10fafab19bf2b21572dd0e2f8cea2.1633593385.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-10-12 13:58:19 -06:00
Linus Torvalds 2d338201d5 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "147 patches, based on 7d2a07b769.

  Subsystems affected by this patch series: mm (memory-hotplug, rmap,
  ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan),
  alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib,
  checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig,
  selftests, ipc, and scripts"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
  scripts: check_extable: fix typo in user error message
  mm/workingset: correct kernel-doc notations
  ipc: replace costly bailout check in sysvipc_find_ipc()
  selftests/memfd: remove unused variable
  Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
  configs: remove the obsolete CONFIG_INPUT_POLLDEV
  prctl: allow to setup brk for et_dyn executables
  pid: cleanup the stale comment mentioning pidmap_init().
  kernel/fork.c: unexport get_{mm,task}_exe_file
  coredump: fix memleak in dump_vma_snapshot()
  fs/coredump.c: log if a core dump is aborted due to changed file permissions
  nilfs2: use refcount_dec_and_lock() to fix potential UAF
  nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
  nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
  nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
  nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
  nilfs2: fix NULL pointer in nilfs_##name##_attr_release
  nilfs2: fix memory leak in nilfs_sysfs_create_device_group
  trap: cleanup trap_init()
  init: move usermodehelper_enable() to populate_rootfs()
  ...
2021-09-08 12:55:35 -07:00
Nathan Chancellor 1c3493bb29 Documentation/llvm: update IRC location
This should have been done with commit 91ed3ed0f7 ("MAINTAINERS: update
ClangBuiltLinux IRC chat") but I did not realize it was in two separate
spots.

Link: https://lkml.kernel.org/r/20210825211823.6406-3-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-08 11:50:26 -07:00
Nathan Chancellor 28f8fc19b2 Documentation/llvm: update mailing list
We are now at llvm@lists.linux.dev.

Link: https://lkml.kernel.org/r/20210825211823.6406-2-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-08 11:50:26 -07:00
Nick Desaulniers f12b034afe scripts/Makefile.clang: default to LLVM_IAS=1
LLVM_IAS=1 controls enabling clang's integrated assembler via
-integrated-as. This was an explicit opt in until we could enable
assembler support in Clang for more architecures. Now we have support
and CI coverage of LLVM_IAS=1 for all architecures except a few more
bugs affecting s390 and powerpc.

This commit flips the default from opt in via LLVM_IAS=1 to opt out via
LLVM_IAS=0.  CI systems or developers that were previously doing builds
with CC=clang or LLVM=1 without explicitly setting LLVM_IAS must now
explicitly opt out via LLVM_IAS=0, otherwise they will be implicitly
opted-in.

This finally shortens the command line invocation when cross compiling
with LLVM to simply:

$ make ARCH=arm64 LLVM=1

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10 09:13:25 +09:00
Nick Desaulniers e08831baa0 Documentation/llvm: update CROSS_COMPILE inferencing
As noted by Masahiro, document how we can generally infer CROSS_COMPILE
(and the more specific details about --target and --prefix) based on
ARCH.

Change use of env vars to command line parameters.

Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10 09:13:25 +09:00
Linus Torvalds 8ca5297e7e Kconfig updates for v5.13
- Change 'option defconfig' to the environment variable
    KCONFIG_DEFCONFIG_LIST
 
  - Refactor tinyconfig without using allnoconfig_y
 
  - Remove 'option allnoconfig_y' syntax
 
  - Change 'option modules' to 'modules'
 
  - Do not use /boot/config-* etc. as base config for cross-compilation
 
  - Fix a search bug in nconf
 
  - Various code cleanups
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Merge tag 'kconfig-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kconfig updates from Masahiro Yamada:

 - Change 'option defconfig' to the environment variable
   KCONFIG_DEFCONFIG_LIST

 - Refactor tinyconfig without using allnoconfig_y

 - Remove 'option allnoconfig_y' syntax

 - Change 'option modules' to 'modules'

 - Do not use /boot/config-* etc. as base config for cross-compilation

 - Fix a search bug in nconf

 - Various code cleanups

* tag 'kconfig-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
  kconfig: refactor .gitignore
  kconfig: highlight xconfig 'comment' lines with '***'
  kconfig: highlight gconfig 'comment' lines with '***'
  kconfig: gconf: remove unused code
  kconfig: remove unused PACKAGE definition
  kconfig: nconf: stop endless search loops
  kconfig: split menu.c out of parser.y
  kconfig: nconf: refactor in print_in_middle()
  kconfig: nconf: remove meaningless wattrset() call from show_menu()
  kconfig: nconf: change set_config_filename() to void function
  kconfig: nconf: refactor attributes setup code
  kconfig: nconf: remove unneeded default for menu prompt
  kconfig: nconf: get rid of (void) casts from wattrset() calls
  kconfig: nconf: fix NORMAL attributes
  kconfig: mconf,nconf: remove unneeded '\0' termination after snprintf()
  kconfig: use /boot/config-* etc. as DEFCONFIG_LIST only for native build
  kconfig: change sym_change_count to a boolean flag
  kconfig: nconf: fix core dump when searching in empty menu
  kconfig: lxdialog: A spello fix and a punctuation added
  kconfig: streamline_config.pl: Couple of typo fixes
  ...
2021-04-29 14:32:00 -07:00
Bhaskar Chowdhury 879a320900 docs: kbuild: Fix a typo in the file Kconfig.recursion-issue-02
s/sematics/semantics/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:13:56 +09:00
Masahiro Yamada 6dd85ff178 kconfig: change "modules" from sub-option to first-level attribute
Now "modules" is the only member of the "option" property.

Remove "option", and move "modules" to the top level property.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:49 +09:00
Masahiro Yamada ab838577aa kconfig: remove allnoconfig_y option
Now that the only user, CONFIG_EMBEDDED has stopped using this option,
remove it entirely.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:49 +09:00
Masahiro Yamada b75b0a819a kconfig: change defconfig_list option to environment variable
"defconfig_list" is a weird option that defines a static symbol that
declares the list of base config files in case the .config does not
exist yet.

This is quite different from other normal symbols; we just abused the
"string" type and the "default" properties to list out the input files.
They must be fixed values since these are searched for and loaded in
the parse stage.

It is an ugly hack, and should not exist in the first place. Providing
this feature as an environment variable is a saner approach.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:48 +09:00
Linus Torvalds 6fbd6cf85a Kbuild updates for v5.12
- Fix false-positive build warnings for ARCH=ia64 builds
 
  - Optimize dictionary size for module compression with xz
 
  - Check the compiler and linker versions in Kconfig
 
  - Fix misuse of extra-y
 
  - Support DWARF v5 debug info
 
  - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
    exceeded the limit
 
  - Add generic syscall{tbl,hdr}.sh for cleanups across arches
 
  - Minor cleanups of genksyms
 
  - Minor cleanups of Kconfig
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Merge tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Fix false-positive build warnings for ARCH=ia64 builds

 - Optimize dictionary size for module compression with xz

 - Check the compiler and linker versions in Kconfig

 - Fix misuse of extra-y

 - Support DWARF v5 debug info

 - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
   exceeded the limit

 - Add generic syscall{tbl,hdr}.sh for cleanups across arches

 - Minor cleanups of genksyms

 - Minor cleanups of Kconfig

* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
  initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
  kbuild: remove deprecated 'always' and 'hostprogs-y/m'
  kbuild: parse C= and M= before changing the working directory
  kbuild: reuse this-makefile to define abs_srctree
  kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
  kconfig: omit --oldaskconfig option for 'make config'
  kconfig: fix 'invalid option' for help option
  kconfig: remove dead code in conf_askvalue()
  kconfig: clean up nested if-conditionals in check_conf()
  kconfig: Remove duplicate call to sym_get_string_value()
  Makefile: Remove # characters from compiler string
  Makefile: reuse CC_VERSION_TEXT
  kbuild: check the minimum linker version in Kconfig
  kbuild: remove ld-version macro
  scripts: add generic syscallhdr.sh
  scripts: add generic syscalltbl.sh
  arch: syscalls: remove $(srctree)/ prefix from syscall tables
  arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
  gen_compile_commands: prune some directories
  kbuild: simplify access to the kernel's version
  ...
2021-02-25 10:17:31 -08:00
Linus Torvalds bdb39c9509 SCSI misc on 20210219
This series consists of the usual driver updates (ufs, ibmvfc,
 qla2xxx, hisi_sas, pm80xx) plus the removal of the gdth driver (which
 is bound to cause conflicts with a trivial change somewhere).  The
 only big major rework of note is the one from Hannes trying to clean
 up our result handling code in the drivers to make it consistent.
 
 Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
 "This series consists of the usual driver updates (ufs, ibmvfc,
  qla2xxx, hisi_sas, pm80xx) plus the removal of the gdth driver (which
  is bound to cause conflicts with a trivial change somewhere).

  The only big major rework of note is the one from Hannes trying to
  clean up our result handling code in the drivers to make it
  consistent"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (194 commits)
  scsi: MAINTAINERS: Adjust to reflect gdth scsi driver removal
  scsi: ufs: Give clk scaling min gear a value
  scsi: lpfc: Fix 'physical' typos
  scsi: megaraid_mbox: Fix spelling of 'allocated'
  scsi: qla2xxx: Simplify the calculation of variables
  scsi: message: fusion: Fix 'physical' typos
  scsi: target: core: Change ASCQ for residual write
  scsi: target: core: Signal WRITE residuals
  scsi: target: core: Set residuals for 4Kn devices
  scsi: hisi_sas: Add trace FIFO debugfs support
  scsi: hisi_sas: Flush workqueue in hisi_sas_v3_remove()
  scsi: hisi_sas: Enable debugfs support by default
  scsi: hisi_sas: Don't check .nr_hw_queues in hisi_sas_task_prep()
  scsi: hisi_sas: Remove deferred probe check in hisi_sas_v2_probe()
  scsi: lpfc: Add auto select on IRQ_POLL
  scsi: ncr53c8xx: Fix typos
  scsi: lpfc: Fix ancient double free
  scsi: qla2xxx: Fix some memory corruption
  scsi: qla2xxx: Remove redundant NULL check
  scsi: megaraid: Fix ifnullfree.cocci warnings
  ...
2021-02-22 10:24:58 -08:00
Linus Torvalds 24880bef41 Remove oprofile and dcookies support
The "oprofile" user-space tools don't use the kernel OPROFILE support any more,
 and haven't in a long time. User-space has been converted to the perf
 interfaces.
 
 The dcookies stuff is only used by the oprofile code. Now that oprofile's
 support is getting removed from the kernel, there is no need for dcookies as
 well.
 
 Remove kernel's old oprofile and dcookies support.
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Merge tag 'oprofile-removal-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux

Pull oprofile and dcookies removal from Viresh Kumar:
 "Remove oprofile and dcookies support

  The 'oprofile' user-space tools don't use the kernel OPROFILE support
  any more, and haven't in a long time. User-space has been converted to
  the perf interfaces.

  The dcookies stuff is only used by the oprofile code. Now that
  oprofile's support is getting removed from the kernel, there is no
  need for dcookies as well.

  Remove kernel's old oprofile and dcookies support"

* tag 'oprofile-removal-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux:
  fs: Remove dcookies support
  drivers: Remove CONFIG_OPROFILE support
  arch: xtensa: Remove CONFIG_OPROFILE support
  arch: x86: Remove CONFIG_OPROFILE support
  arch: sparc: Remove CONFIG_OPROFILE support
  arch: sh: Remove CONFIG_OPROFILE support
  arch: s390: Remove CONFIG_OPROFILE support
  arch: powerpc: Remove oprofile
  arch: powerpc: Stop building and using oprofile
  arch: parisc: Remove CONFIG_OPROFILE support
  arch: mips: Remove CONFIG_OPROFILE support
  arch: microblaze: Remove CONFIG_OPROFILE support
  arch: ia64: Remove rest of perfmon support
  arch: ia64: Remove CONFIG_OPROFILE support
  arch: hexagon: Don't select HAVE_OPROFILE
  arch: arc: Remove CONFIG_OPROFILE support
  arch: arm: Remove CONFIG_OPROFILE support
  arch: alpha: Remove CONFIG_OPROFILE support
2021-02-21 10:40:34 -08:00
Masahiro Yamada 3d277907c2 kbuild: doc: remove "Objects which export symbols" section
EXPORT_SYMBOL is unrelated to makefiles. No need to mention it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16 12:01:45 +09:00
Masahiro Yamada d8d2d38275 kbuild: remove PYTHON variable
Python retired in 2020, and some distributions do not provide the
'python' command any more.

As in commit 51839e29cb ("scripts: switch explicitly to Python 3"),
we need to use more specific 'python3' to invoke scripts even if they
are written in a way compatible with both Python 2 and 3.

This commit removes the variable 'PYTHON', and switches the existing
users to 'PYTHON3'.

BTW, PEP 394 (https://www.python.org/dev/peps/pep-0394/) is a helpful
material.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-01 10:37:19 +09:00
Nathan Chancellor ed4e9e615b Documentation/llvm: Add a section about supported architectures
The most common question around building the Linux kernel with clang is
"does it work?" and the answer has always been "it depends on your
architecture, configuration, and LLVM version" with no hard answers for
users wanting to experiment. LLVM support has significantly improved
over the past couple of years, resulting in more architectures and
configurations supported, and continuous integration has made it easier
to see what works and what does not.

Add a section that goes over what architectures are supported in the
current kernel version, how they should be built (with just clang or the
LLVM utilities as well), and the level of support they receive. This
will make it easier for people to try out building their kernel with
LLVM and reporting issues that come about from it.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulnier@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-30 06:06:35 +09:00
Viresh Kumar 2083fecd1c arch: sparc: Remove CONFIG_OPROFILE support
The "oprofile" user-space tools don't use the kernel OPROFILE support
any more, and haven't in a long time. User-space has been converted to
the perf interfaces.

Remove the old oprofile's architecture specific support.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Robert Richter <rric@kernel.org>
Acked-by: William Cohen <wcohen@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
2021-01-29 10:05:51 +05:30
Masahiro Yamada 9b6164342e doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.

[1] Drop the version information

The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c5
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.

We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.

[2] Drop the C compiler statements

Since commit 77342a02ff ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.

[3] Drop supported architectures

As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".

[4] Update the apt-get example

We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.

[5] Update the build target

Since commit ce2fd53a10 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.

[6] Update the steps for adding a new plugin

At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdf ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e5815 ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.

The sub-directory support was never used by anyone, and removed by
commit c17d6179ad ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").

Remove the useless $(src)/ prefix.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-26 06:23:20 +09:00
Robert Karszniewicz 1cabe74f14 Documentation/Kbuild: Remove references to gcc-plugin.sh
gcc-plugin.sh has been removed in commit
1e860048c5 ("gcc-plugins: simplify GCC plugin-dev capability test").

Signed-off-by: Robert Karszniewicz <r.karszniewicz@phytec.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 18:30:26 +09:00
Hannes Reinecke 0653c358d2 scsi: Drop gdth driver
The gdth driver refers to a SCSI parallel, PCI-only HBA RAID adapter which
was manufactured by the now-defunct ICP Vortex company, later acquired by
Adaptec and superseded by the aacraid series of controllers.  The driver
itself would require a major overhaul before any modifications can be
attempted, but seeing that it's unlikely to have any users left it should
rather be removed completely.

Link: https://lore.kernel.org/r/20210113090500.129644-2-hare@suse.de
Cautiously-Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-01-22 21:14:07 -05:00
Viresh Kumar 5625dcfbbc Documentation: kbuild: Fix section reference
Section 3.11 was incorrectly called 3.9, fix it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-11 05:14:38 +09:00
Linus Torvalds 2762db756f Kconfig updates for v5.11
- Support only Qt5 for qconf
 
  - Validate signal/slot connection at compile time of qconf
 
  - Sanitize header includes
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Merge tag 'kconfig-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kconfig updates from Masahiro Yamada:

 - Support only Qt5 for qconf

 - Validate signal/slot connection at compile time of qconf

 - Sanitize header includes

* tag 'kconfig-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: doc: fix $(fileno) to $(filename)
  kconfig: fix return value of do_error_if()
  kconfig: clean up header inclusion
  kconfig: qconf: show Qt version in the About dialog
  kconfig: make lkc.h self-sufficient #include-wise
  kconfig: qconf: convert to Qt5 new signal/slot connection syntax
  kconfig: qconf: use a variable to pass packages to pkg-config
  kconfig: qconf: drop Qt4 support
2020-12-22 14:04:25 -08:00
Masahiro Yamada 90d39628ac kconfig: doc: fix $(fileno) to $(filename)
This is a typo.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 16:01:44 +09:00
Geert Uytterhoeven 18084e435f Documentation/kbuild: Document platform dependency practises
Document best practises for using architecture and platform dependencies.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Geert Uytterhoeven c613583b6a Documentation/kbuild: Document COMPILE_TEST dependencies
Document best practises for using COMPILE_TEST dependencies.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Masahiro Yamada c0ea806f87 kbuild: doc: document subdir-y syntax
There is no explanation about subdir-y.

Let's document it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2020-12-21 13:57:07 +09:00
Masahiro Yamada d0e628cd81 kbuild: doc: clarify the difference between extra-y and always-y
The difference between extra-y and always-y is obscure.

Basically, Kbuild builds targets listed in extra-y and always-y in
visited Makefiles without relying on any dependency.

The difference is that extra-y is used to list the targets needed for
vmlinux whereas always-y is used to list the targets that must be always
built irrespective of final targets.

Kbuild skips extra-y when it is building only modules (i.e.
'make modules'). This is the long-standing behavior since extra-y was
introduced in 2003, and it is explained in that commit log [1].

For clarification, this is the extra-y vs always-y table:

                  extra-y    always-y
  'make'             y          y
  'make vmlinux'     y          y
  'make modules'     n          y

Kbuild skips extra-y also when building external modules since obviously
it never builds vmlinux.

Unfortunately, extra-y is wrongly used in many places of upstream code,
and even in external modules.

Using extra-y in external module Makefiles is wrong. What you should
use is probably always-y or 'targets'.

The current documentation for extra-y is misleading. I rewrote it, and
moved it to the section 3.7.

always-y is not documented anywhere. I added.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=f94e5fd7e5d09a56a60670a9bb211a791654bba8

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2020-12-21 13:57:07 +09:00
Masahiro Yamada 39bb232ae6 kbuild: doc: split if_changed explanation to a separate section
The if_changed macro is currently explained in the section
"Commands useful for building a boot image", but the use of
if_changed is not limited to the boot image.

It is often used together with custom rules. Let's split it as a
separate section, and insert it after the "Custom Rules" section.

I slightly reworded the explanation, re-numbered to fill the <deleted>
section, and also fixed the broken indentation of the Note: part.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:07 +09:00
Masahiro Yamada 41cac0834f kbuild: doc: merge 'Special Rules' and 'Custom kbuild commands' sections
The two sections "3.10 Special Rules" and "7.8 Custom kbuild commands"
are related because you must understand both of them when you write
custom rules.

Actually I do not understand the policy about what to go into
"3 The kbuild files" and what into "7 Architecture Makefile".

This commit reworks the custom rule explanation as follows:

 - Merged "7.8 Custom kbuild commands" into "3.10 Special Rules".

 - Reword "Special Rules" to "Custom Rules" for consistency.

 - Update the example for kecho because the blackfin Makefile
   does not exist any more.

 - Replace the example for cmd_<command> with a simpler one.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:07 +09:00
Masahiro Yamada 23b53061ad kbuild: doc: fix 'List directories to visit when descending' section
Fix stale information:

 - Fix the section number in the reference from 6.4 to 7.4.

 - Remove init-y and net-y. They were removed by commit 23febe375d
   ("kbuild: merge init-y into core-y") and commit 95fb6317b3
   ("kbuild: merge net-y and virt-y into drivers-y"), respectively.

 - Update the example because arch/sparc64/Makefile does not exit.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:07 +09:00
Masahiro Yamada 8c4d9b145b kbuild: doc: replace arch/$(ARCH)/ with arch/$(SRCARCH)/
Precisely speaking, the arch directory is specified by $(SRCARCH),
not $(ARCH).

In old days, $(ARCH) actually matched to the arch directory because
32-bit and 64-bit were supported as separate architectures.

Most architectures (except arm/arm64) were unified like follows:

    arch/i386, arch/x86_64    ->  arch/x86
    arch/sh, arch/sh64        ->  arch/sh
    arch/sparc, arch/sparc64  ->  arch/sparc

To not break the user interface, commit 6752ed90da ("Kbuild: allow
arch/xxx to use a different source path") introduced SRCARCH to point
to the arch directory, still allowing to pass in the former ARCH=i386
or ARCH=x86_64.

Update the documents for preciseness, and add the explanation of SRCARCH.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2020-12-21 13:56:58 +09:00
Masahiro Yamada b044a535d9 kbuild: doc: update the description about kbuild Makefiles
This line was written in 2003. Now we have much more Makefiles.

The number of Makefiles is not important. The point is we have a
Makefile in (almost) every directory.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:55:29 +09:00
Vasily Gorbik d9b5665fb3 kbuild: remove unused OBJSIZE
The "size" tool has been solely used by s390 to enforce .bss section usage
restrictions in early startup code. Since commit 980d5f9ab3 ("s390/boot:
enable .bss section for compressed kernel") and commit 2e83e0eb85
("s390: clean .bss before running uncompressed kernel") these restrictions
have been lifted for the decompressor and uncompressed kernel and the
size tool is now unused.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-02 11:31:00 +09:00
Lukas Bulwahn eb38f37c3c kbuild: doc: describe proper script invocation
During an investigation to fix up the execute bits of scripts in the
kernel repository, Andrew Morton and Kees Cook pointed out that the
execute bit should not matter, and that build scripts cannot rely on that.
Kees could not point to any documentation, though.

Masahiro Yamada explained the convention of setting execute bits to make
it easier for manual script invocation.

Provide some basic documentation how the build shall invoke scripts, such
that the execute bits do not matter, and acknowledge that execute bits are
useful nonetheless.

This serves as reference for further clean-up patches in the future.

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ujjwal Kumar <ujjwalkumar0501@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/lkml/20200830174409.c24c3f67addcce0cea9a9d4c@linux-foundation.org/
Link: https://lore.kernel.org/lkml/202008271102.FEB906C88@keescook/
Link: https://lore.kernel.org/linux-kbuild/CAK7LNAQdrvMkDA6ApDJCGr+5db8SiPo=G+p8EiOvnnGvEN80gA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20201001075723.24246-1-lukas.bulwahn@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-13 18:38:26 -07:00