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: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

Pull Kbuild updates from Masahiro Yamada:

 - Make Kconfig parse the input .config more precisely

 - Support W=c and W=e options for Kconfig

 - Set Kconfig int/hex symbols to zero if the 'default' property is
   missing

 - Add .editorconfig

 - Add scripts/git.orderFile

 - Add a script to detect backward-incompatible changes in UAPI headers

 - Resolve the symlink passed to O= option properly

 - Use the user-supplied mtime for all files in the builtin initramfs,
   which provides better reproducible builds

 - Fix the direct execution of debian/rules for Debian package builds

 - Use build ID instead of the .gnu_debuglink section for the Debian dbg
   package

* tag 'kbuild-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (53 commits)
  kbuild: deb-pkg: use debian/<package> for tmpdir
  kbuild: deb-pkg: move 'make headers' to build-arch
  kbuild: deb-pkg: do not search for 'scripts' directory under arch/
  kbuild: deb-pkg: use build ID instead of debug link for dbg package
  kbuild: deb-pkg: use more debhelper commands in builddeb
  kbuild: deb-pkg: remove unneeded '-f $srctree/Makefile' in debian/rules
  kbuild: deb-pkg: allow to run debian/rules from output directory
  kbuild: deb-pkg: set DEB_* variables if debian/rules is directly executed
  kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules
  kbuild: deb-pkg: factor out common Make options in debian/rules
  kbuild: deb-pkg: hard-code Build-Depends
  kbuild: deb-pkg: split debian/copyright from the mkdebian script
  gen_init_cpio: Apply mtime supplied by user to all file types
  kbuild: resolve symlinks for O= properly
  docs: dev-tools: Add UAPI checker documentation
  check-uapi: Introduce check-uapi.sh
  scripts: Introduce a default git.orderFile
  kconfig: WERROR unmet symbol dependency
  Add .editorconfig file for basic formatting
  kconfig: Use KCONFIG_CONFIG instead of .config
  ...

Currently gen_init_cpio -d <timestamp> is applied to symlinks,
directories and special files. These files are created by
gen_init_cpio from their description. Without <timestamp> option
current time(NULL) is used. And regular files that go in initramfs
are created before cpio generation, so their mtime(s) are preserved.

This is usually not an issue as reproducible builds should rebuild
everything in the distribution, including binaries, configs and whatever
other regular files may find their way into kernel's initramfs.

On the other hand, gen_initramfs.sh usage claims:
>	-d <date>      Use date for all file mtime values

Ar Arista initramfs files are managed with version control system
that preserves mtime. Those are configs, boot parameters, init scripts,
version files, platform-specific files, probably some others, too.

While it's certainly possible to work this around by copying the file
into temp directory and adjusting mtime prior to gen_init_cpio call,
I don't see why it needs workarounds.

The intended user of -d <date> option is the one that needs to create
a reproducible build, see commit a8b8017c34fe ("initramfs: Use
KBUILD_BUILD_TIMESTAMP for generated entries"). If a user wants
the build reproduction, they use -d <date>, which can be set on all
types of files, without surprising exceptions and workarounds.
Let's KISS here and just apply the time that user specified
with -d option.

Based-on-a-patch-by: Baptiste Covolato <baptiste@arista.com>
Link: https://lore.kernel.org/lkml/20181025215133.20138-1-baptiste@arista.com/
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Use "Its" or "its" for possessive instead of "it's" (contraction
for "it is").

Link: https://lkml.kernel.org/r/20231210053429.23146-1-rdunlap@infradead.org
Fixes: db2aa7fd15e8 ("initramfs: allow again choice of the embedded initram compression algorithm")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Acked-by: "Francisco Blas Izquierdo Riera (klondike)" <klondike@klondike.es>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The Itanium architecture is obsolete, and an informal survey [0] reveals
that any residual use of Itanium hardware in production is mostly HP-UX
or OpenVMS based. The use of Linux on Itanium appears to be limited to
enthusiasts that occasionally boot a fresh Linux kernel to see whether
things are still working as intended, and perhaps to churn out some
distro packages that are rarely used in practice.

None of the original companies behind Itanium still produce or support
any hardware or software for the architecture, and it is listed as
'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers
that contributed on behalf of those companies (nor anyone else, for that
matter) have been willing to support or maintain the architecture
upstream or even be responsible for applying the odd fix. The Intel
firmware team removed all IA-64 support from the Tianocore/EDK2
reference implementation of EFI in 2018. (Itanium is the original
architecture for which EFI was developed, and the way Linux supports it
deviates significantly from other architectures.) Some distros, such as
Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have
dropped support years ago.

While the argument is being made [1] that there is a 'for the common
good' angle to being able to build and run existing projects such as the
Grid Community Toolkit [2] on Itanium for interoperability testing, the
fact remains that none of those projects are known to be deployed on
Linux/ia64, and very few people actually have access to such a system in
the first place. Even if there were ways imaginable in which Linux/ia64
could be put to good use today, what matters is whether anyone is
actually doing that, and this does not appear to be the case.

There are no emulators widely available, and so boot testing Itanium is
generally infeasible for ordinary contributors. GCC still supports IA-64
but its compile farm [3] no longer has any IA-64 machines. GLIBC would
like to get rid of IA-64 [4] too because it would permit some overdue
code cleanups. In summary, the benefits to the ecosystem of having IA-64
be part of it are mostly theoretical, whereas the maintenance overhead
of keeping it supported is real.

So let's rip off the band aid, and remove the IA-64 arch code entirely.
This follows the timeline proposed by the Debian/ia64 maintainer [5],
which removes support in a controlled manner, leaving IA-64 in a known
good state in the most recent LTS release. Other projects will follow
once the kernel support is removed.

[0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/
[1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/
[2] https://gridcf.org/gct-docs/latest/index.html
[3] https://cfarm.tetaneutral.net/machines/list/
[4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/
[5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/

Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

gen_initramfs.sh has an internal dependency on KBUILD_BUILD_TIMESTAMP
for generating file mtimes that is not exposed to make, so changing
KBUILD_BUILD_TIMESTAMP will not trigger a rebuild of the archive.

Declare the mtime date as a new parameter to gen_initramfs.sh to encode
KBUILD_BUILD_TIMESTAMP in the shell command, thereby making make aware
of the dependency.

It will rebuild if KBUILD_BUILD_TIMESTAMP changes or is newly set/unset.
It will _not_ rebuild if KBUILD_BUILD_TIMESTAMP is unset before and
after. This should be fine for anyone who doesn't care about setting
specific build times in the first place.

Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Tested-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Similar to commit 4c9d410f32b3 ("initramfs: Check timestamp to prevent
broken cpio archive"), except asserts that the timestamp is
non-negative. This can happen when the KBUILD_BUILD_TIMESTAMP is a value
before UNIX epoch, which may be set when making reproducible builds that
don't want to look like they use a valid date.

While support for dates before 1970 might not be supported, this is more
about preventing undetected CPIO corruption. The printf's use a minimum
length format specifier, and will happily make the field longer than 8
characters if they need to.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Tested-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The file variable is assigned first, it does not need to be initialized.

Link: https://lkml.kernel.org/r/20220919014406.3242-1-zeming@nfschina.com
Signed-off-by: Li zeming <zeming@nfschina.com>
Cc: Li zeming <zeming@nfschina.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Pull misc updates from Andrew Morton:
 "The non-MM patch queue for this merge window.

  Not a lot of material this cycle. Many singleton patches against
  various subsystems. Most notably some maintenance work in ocfs2
  and initramfs"

* tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits)
  kcov: update pos before writing pc in trace function
  ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
  ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock
  fs/ntfs: remove redundant variable idx
  fat: remove time truncations in vfat_create/vfat_mkdir
  fat: report creation time in statx
  fat: ignore ctime updates, and keep ctime identical to mtime in memory
  fat: split fat_truncate_time() into separate functions
  MAINTAINERS: add Muchun as a memcg reviewer
  proc/sysctl: make protected_* world readable
  ia64: mca: drop redundant spinlock initialization
  tty: fix deadlock caused by calling printk() under tty_port->lock
  relay: remove redundant assignment to pointer buf
  fs/ntfs3: validate BOOT sectors_per_clusters
  lib/string_helpers: fix not adding strarray to device's resource list
  kernel/crash_core.c: remove redundant check of ck_cmdline
  ELF, uapi: fixup ELF_ST_TYPE definition
  ipc/mqueue: use get_tree_nodev() in mqueue_get_tree()
  ipc: update semtimedop() to use hrtimer
  ipc/sem: remove redundant assignments
  ...

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
  ...