If RUST_LIB_SRC is defined in the top-level Makefile (via an environment
variable or command line), it is already exported.

The only situation where it is defined but not exported is when the
top-level Makefile is wrapped by another Makefile (e.g., GNUmakefile).
I cannot think of any other use cases.

I know some people use this tip to define custom variables. However,
even in that case, you can export it directly in the wrapper Makefile.

Example GNUmakefile:

    export RUST_LIB_SRC = /path/to/your/sysroot/lib/rustlib/src/rust/library
    include Makefile
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>

The append operation was introduced in
commit b1a1a1a0 ("kbuild: lto: postpone objtool")
when the command was created from two parts.
In commit 850ded46 ("kbuild: Fix TRIM_UNUSED_KSYMS with LTO_CLANG")
however the first part was removed again, making the append operation
unnecessary.

To keep this command definition aligned with all other command
definitions, remove the append again.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Cache expression values to avoid recalculating them repeatedly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, every expression in Kconfig files produces a new abstract
syntax tree (AST), even if it is identical to a previously encountered
one.

Consider the following code:

    config FOO
           bool "FOO"
           depends on (A || B) && C

    config BAR
           bool "BAR"
           depends on (A || B) && C

    config BAZ
           bool "BAZ"
           depends on A || B

The "depends on" lines are similar, but currently a separate AST is
allocated for each one.

The current data structure looks like this:

  FOO->dep ==> AND        BAR->dep ==> AND        BAZ->dep ==> OR
              /   \                   /   \                   /  \
            OR     C                OR     C                 A    B
           /  \                    /  \
          A    B                  A    B

This is redundant; FOO->dep and BAR->dep have identical ASTs but
different memory instances.

We can optimize this; FOO->dep and BAR->dep can share the same AST, and
BAZ->dep can reference its sub tree.

The optimized data structure looks like this:

  FOO->dep, BAR->dep ==> AND
                        /   \
         BAZ->dep ==> OR     C
                     /  \
                    A    B

This commit introduces a hash table to keep track of allocated
expressions. If an identical expression is found, it is reused.

This does not necessarily result in memory savings, as menu_finalize()
transforms expressions without freeing up stale ones. This will be
addressed later.

One optimization that can be easily implemented is caching the
expression's value. Once FOO's dependency, (A || B) && C, is calculated,
it can be cached, eliminating the need to recalculate it for BAR.

This commit also reverts commit e983b7b1 ("kconfig/menu.c: fix
multiple references to expressions in menu_add_prop()").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, expr_eliminate_dups() passes two identical pointers down to
expr_eliminate_dups1(), which later skips processing identical leaves.

This approach is somewhat tricky and, more importantly, it will not work
with the refactoring made in the next commit.

This commit slightly changes the recursion logic; it deduplicates both
the left and right arms, and then passes them to expr_eliminate_dups1().
expr_eliminate_dups() should produce the same result.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Provide explanations for complex transformations.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This clarifies the behavior of these functions.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This function was originally added by commit 8af27e1d ("fixdep: use
hash table instead of a single array").

Move it to scripts/include/ so that other host programs can use it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Change the 'overflow' variable to bool. Also, remove unnecessary
parentheses.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

After commit 64e16609 ("kallsyms: get rid of code for absolute,
kallsyms"), there is only one call site for output_address(). Squash it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When CONFIG_BUILTIN_MODULE_RANGES is enabled, the modules.builtin.ranges
file should be installed in the module install location.
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>
Tested-by: Sam James <sam@gentoo.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The modules.builtin.ranges offset range data for builtin modules is
generated at compile time based on the list of built-in modules and
the vmlinux.map and vmlinux.o.map linker maps.  This data can be used
to determine whether a symbol at a particular address belongs to
module code that was configured to be compiled into the kernel proper
as a built-in module (rather than as a standalone module).

This patch adds a script that uses the generated modules.builtin.ranges
data to annotate the symbols in the System.map with module names if
their address falls within a range that belongs to one or more built-in
modules.

It then processes the vmlinux.map (and if needed, vmlinux.o.map) to
verify the annotation:

  - For each top-level section:
     - For each object in the section:
        - Determine whether the object is part of a built-in module
          (using modules.builtin and the .*.cmd file used to compile
           the object as suggested in [0])
        - For each symbol in that object, verify that the built-in
          module association (or lack thereof) matches the annotation
          given to the symbol.
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Sam James <sam@gentoo.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Create file module.builtin.ranges that can be used to find where
built-in modules are located by their addresses. This will be useful for
tracing tools to find what functions are for various built-in modules.

The offset range data for builtin modules is generated using:
 - modules.builtin: associates object files with module names
 - vmlinux.map: provides load order of sections and offset of first member
    per section
 - vmlinux.o.map: provides offset of object file content per section
 - .*.cmd: build cmd file with KBUILD_MODFILE

The generated data will look like:

.text 00000000-00000000 = _text
.text 0000baf0-0000cb10 amd_uncore
.text 0009bd10-0009c8e0 iosf_mbi
...
.text 00b9f080-00ba011a intel_skl_int3472_discrete
.text 00ba0120-00ba03c0 intel_skl_int3472_discrete intel_skl_int3472_tps68470
.text 00ba03c0-00ba08d6 intel_skl_int3472_tps68470
...
.data 00000000-00000000 = _sdata
.data 0000f020-0000f680 amd_uncore

For each ELF section, it lists the offset of the first symbol.  This can
be used to determine the base address of the section at runtime.

Next, it lists (in strict ascending order) offset ranges in that section
that cover the symbols of one or more builtin modules.  Multiple ranges
can apply to a single module, and ranges can be shared between modules.

The CONFIG_BUILTIN_MODULE_RANGES option controls whether offset range data
is generated for kernel modules that are built into the kernel image.

How it works:

 1. The modules.builtin file is parsed to obtain a list of built-in
    module names and their associated object names (the .ko file that
    the module would be in if it were a loadable module, hereafter
    referred to as <kmodfile>).  This object name can be used to
    identify objects in the kernel compile because any C or assembler
    code that ends up into a built-in module will have the option
    -DKBUILD_MODFILE=<kmodfile> present in its build command, and those
    can be found in the .<obj>.cmd file in the kernel build tree.

    If an object is part of multiple modules, they will all be listed
    in the KBUILD_MODFILE option argument.

    This allows us to conclusively determine whether an object in the
    kernel build belong to any modules, and which.

 2. The vmlinux.map is parsed next to determine the base address of each
    top level section so that all addresses into the section can be
    turned into offsets.  This makes it possible to handle sections
    getting loaded at different addresses at system boot.

    We also determine an 'anchor' symbol at the beginning of each
    section to make it possible to calculate the true base address of
    a section at runtime (i.e. symbol address - symbol offset).

    We collect start addresses of sections that are included in the top
    level section.  This is used when vmlinux is linked using vmlinux.o,
    because in that case, we need to look at the vmlinux.o linker map to
    know what object a symbol is found in.

    And finally, we process each symbol that is listed in vmlinux.map
    (or vmlinux.o.map) based on the following structure:

    vmlinux linked from vmlinux.a:

      vmlinux.map:
        <top level section>
          <included section>  -- might be same as top level section)
            <object>          -- built-in association known
              <symbol>        -- belongs to module(s) object belongs to
              ...

    vmlinux linked from vmlinux.o:

      vmlinux.map:
        <top level section>
          <included section>  -- might be same as top level section)
            vmlinux.o         -- need to use vmlinux.o.map
              <symbol>        -- ignored
              ...

      vmlinux.o.map:
        <section>
            <object>          -- built-in association known
              <symbol>        -- belongs to module(s) object belongs to
              ...

 3. As sections, objects, and symbols are processed, offset ranges are
    constructed in a straight-forward way:

      - If the symbol belongs to one or more built-in modules:
          - If we were working on the same module(s), extend the range
            to include this object
          - If we were working on another module(s), close that range,
            and start the new one
      - If the symbol does not belong to any built-in modules:
          - If we were working on a module(s) range, close that range
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Sam James <sam@gentoo.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

In order to create the file at build time, modules.builtin.ranges, that
contains the range of addresses for all built-in modules, there needs to
be a way to identify what code is compiled into modules.

To identify what code is compiled into modules during a kernel build,
one can look for the presence of the -DKBUILD_MODFILE and -DKBUILD_MODNAME
options in the compile command lines.  A simple grep in .*.cmd files for
those options is sufficient for this.

Unfortunately, these options are only passed when compiling C source files.
Various modules also include objects built from assembler source, and these
options are not passed in that case.

Adding $(modfile_flags) to modkern_aflags (similar to modkern_cflags), and
adding $(modname_flags) to a_flags (similar to c_flags) makes it possible
to identify which objects are compiled into modules for both C and
assembler source files.  While KBUILD_MODFILE is sufficient to generate
the modules ranges data, KBUILD_MODNAME is passed as well for consistency
with the C source code case.
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Sam James <sam@gentoo.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When building the Linux kernel on an aarch64 macOS based host, if we don't
specify a value for ARCH when invoking make, we default to arm and thus
multi_v7_defconfig rather than the expected arm64 and arm64's defconfig.

This is because subarch.include invokes `uname -m` which on MacOS hosts
evaluates to `arm64` but on Linux hosts evaluates to `aarch64`,

This allows us to build ARCH=arm64 natively on macOS (as in ARCH need
not be specified on an aarch64-based system).

Avoid matching arm64 by excluding it from the arm.* sed expression.
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Suggested-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Add more macros used for removing hash table entries.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/Makefile.lib is included not only from scripts/Makefile.build
but also from scripts/Makefile.{modfinal,package,vmlinux,vmlinux_o},
where DT build rules are not required.

Split the DT build rules out to scripts/Makefile.dtbs, and include it
only when necessary.

While I was here, I added $(DT_TMP_SCHEMA) as a prerequisite of
$(multi-dtb-y).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Flex and Bison are used only for host programs. Move their intermediate
target processing from scripts/Makefile.build to scripts/Makefile.host.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Various information about modules is compiled into the info sections.
For that a dedicated .mod.c file is generated by modpost for each module
and then linked into the module.
However most of the information in the .mod.c is the same for all
modules, internal and external.
Split the shared information into a dedicated source file that is
compiled once and then linked into all modules.

This avoids frequent rebuilds for all .mod.c files when using
CONFIG_LOCALVERSION_AUTO because the local version ends up in .mod.c
through UTS_RELEASE and VERMAGIC_STRING.
The modules are still relinked in this case.

The code is also easier to maintain as it's now in a proper source file
instead of an inline string literal.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Commit abe11dde ("ARC: [plat-arcfpga]: Enabling DeviceTree for
Angel4 board") changed the default built-in DTB from "skeleton" to
"angel4".

Commit fd155792 ("ARC: [plat_arcfpga]->[plat_sim]") changed it
from "angel4" to "nsim_700".
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Vineet Gupta <vgupta@kernel.org>

Remove the recently-added dependency on the truncate program for
building the kernel. truncate is not available when building the kernel
under Yocto. It could be added, but it would be better just to avoid
the unnecessary dependency.

Fixes: 1472464c ("kbuild: avoid scripts/kallsyms parsing /dev/null")
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Add a new debug package to the PKGBUILD for the pacman-pkg target. The
debug package includes the non-stripped vmlinux file with debug symbols
for kernel debugging and profiling. The file is installed at
/usr/src/debug/${pkgbase}, with a symbolic link at
/usr/lib/modules/$(uname -r)/build/vmlinux. The debug package is built
by default.
Signed-off-by: Jose Fernandez <jose.fernandez@linux.dev>
Reviewed-by: Peter Jung <ptr1337@cachyos.org>
Acked-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

There are a few lines in the kbuild-language.rst document which
obliquely reference the behavior of config options without prompts.
But there is nothing in the obvious location that explicitly calls
out that users cannot edit config options unless they have a prompt.
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Commit 5ce2176b ("genksyms: adjust the output format to modpost")
stopped generating *.symversions files.

Remove the left-over from the .gitignore file and the 'clean' rule.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

With commit cda5f94e ("modpost: avoid using the alias attribute"),
only two log levels remain: LOG_WARN and LOG_ERROR. Simplify this by
making it a boolean variable.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

objtree is defined and exported by the top-level Makefile. I prefer
not to override it.

There is no need to pass the absolute path of objtree. PKGBUILD can
detect it by itself.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by:   Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Christian Heusel <christian@heusel.eu>

All build and package functions share the following commands:

  export MAKEFLAGS="${KBUILD_MAKEFLAGS}"
  cd "${objtree}"

Factor out the common code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by:   Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Christian Heusel <christian@heusel.eu>

Introduce the PACMAN_EXTRAPACKAGES variable in PKGBUILD to allow users
to specify which additional packages are built by the pacman-pkg target.

Previously, the api-headers package was always included, and the headers
package was included only if CONFIG_MODULES=y. With this change, both
headers and api-headers packages are included by default. Users can now
control this behavior by setting PACMAN_EXTRAPACKAGES to a
space-separated list of desired extra packages or leaving it empty to
exclude all.

For example, to build only the base package without extras:

make pacman-pkg PACMAN_EXTRAPACKAGES=""
Signed-off-by: Jose Fernandez <jose.fernandez@linux.dev>
Reviewed-by: Peter Jung <ptr1337@cachyos.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Christian Heusel <christian@heusel.eu>
Tested-by: Christian Heusel <christian@heusel.eu>
Acked-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This commit improves the section mismatch warning format when there is
no suitable symbol name to print.

The section mismatch warning prints the reference source in the form
of <symbol_name>+<offset> and the reference destination in the form
of <symbol_name>.

However, there are some corner cases where <symbol_name> becomes
"(unknown)", as reported in commit 23dfd914 ("modpost: fix null
pointer dereference").

In such cases, it is better to print the symbol address.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When malloc() fails, there is not much userspace programs can do.
xmalloc() is useful to bail out on a memory allocation failure.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When malloc() or realloc() fails, there is not much userspace programs
can do. xmalloc() and xrealloc() are useful to bail out on a memory
allocation failure.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I think x*alloc() functions are cleaner.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

These functions will be useful for other host programs.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

P_SYMBOL is a pseudo property that was previously used for data linking
purposes.

It is no longer used except for debug prints. Remove it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I believe its last usage was in the following code:

    if (prop == NULL)
            prop = stack->sym->prop;

This code was previously used to print the file name and line number of
associated symbols in sym_check_print_recursive(), which was removed by
commit 9d0d2660 ("kconfig: recursive checks drop file/lineno").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Since commit ca4c74ba ("kconfig: remove P_CHOICE property"),
menu_finalize() no longer calls menu_add_symbol(). No function
references cur_filename or cur_lineno after yyparse().
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This reverts the following commits:

 - 236dec05 ("kconfig: tinyconfig: provide whole choice blocks to
   avoid warnings")

 - b0f26972 ("x86/config: Fix warning for 'make ARCH=x86_64
   tinyconfig'")

Since commit f79dc03f ("kconfig: refactor choice value calculation"),
it is no longer necessary to disable the remaining options in choice
blocks.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

Parallel execution is supported by GNU Make:

  $ make -j<N> modules_install

It is questionable to enable multithreading within each zstd process
by default.

If you still want to do it, you can use the environment variable:

  $ ZSTD_NBTHREADS=<N> make modules_install
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>

Commit 3f1b0e1f (".gitignore update") added *.orig and *.rej
patterns to .gitignore in v2.6.23. The commit message didn't give a
rationale. Later on, commit 1f5d3a6b ("Remove *.rej pattern from
.gitignore") removed the *.rej pattern in v2.6.26, on the rationale that
*.rej files indicated something went really wrong and should not be
ignored.

The *.rej files are now shown by `git status`, which helps located
conflicts when applying patches and lowers the probability that they
will go unnoticed. It is however still easy to overlook the *.orig files
which slowly polute the source tree. That's not as big of a deal as not
noticing a conflict, but it's still not nice.

Drop the *.orig pattern from .gitignore to avoid this and help keep the
source tree clean.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[masahiroy@kernel.org:
I do not have a strong opinion about this. Perhaps some people may have
a different opinion.

If you are someone who wants to ignore *.orig, it is likely you would
want to do so across all projects. Then, $XDG_CONFIG_HOME/git/ignore
would be more suitable for your needs. gitignore(5) suggests, "Patterns
which a user wants Git to ignore in all situations generally go into a
file specified by core.excludesFile in the user's ~/.gitconfig".

Please note that you cannot do the opposite; if *.orig is ignored by
the project's .gitignore, you cannot override the decision because
$XDG_CONFIG_HOME/git/ignore has a lower priority.

If *.orig is sitting on the fence, I'd leave it to the users. ]
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

A long standing issue in the upstream kernel packaging is that the
linux-headers package is not cross-compiled.

For example, you can cross-build Debian packages for arm64 by running
the following command:

  $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bindeb-pkg

However, the generated linux-headers-*_arm64.deb is useless because the
host programs in it were built for your build machine architecture
(likely x86), not arm64.

The Debian kernel maintains its own Makefiles to cross-compile host
tools without relying on Kbuild. [1]

Instead of adding such full custom Makefiles, this commit adds a small
piece of code to cross-compile host programs located under the scripts/
directory.

A straightforward solution is to pass HOSTCC=${CROSS_COMPILE}gcc, but it
would also cross-compile scripts/basic/fixdep, which needs to be native
to process the if_changed_dep macro. (This approach may work under some
circumstances; you can execute foreign architecture programs with the
help of binfmt_misc because Debian systems enable CONFIG_BINFMT_MISC,
but it would require installing QEMU and libc for that architecture.)

A trick is to use the external module build (KBUILD_EXTMOD=), which
does not rebuild scripts/basic/fixdep. ${CC} needs to be able to link
userspace programs (CONFIG_CC_CAN_LINK=y).

There are known limitations:

 - GCC plugins

   It would possible to rebuild GCC plugins for the target architecture
   by passing HOSTCXX=${CROSS_COMPILE}g++ with necessary packages
   installed, but gcc on the installed system emits
   "cc1: error: incompatible gcc/plugin versions".

 - objtool and resolve_btfids

   These are built by the tools build system. They are not covered by
   the current solution. The resulting linux-headers package is broken
   if CONFIG_OBJTOOL or CONFIG_DEBUG_INFO_BTF is enabled.

I only tested this with Debian, but it should work for other package
systems as well.

[1]: https://salsa.debian.org/kernel-team/linux/-/blob/debian/6.9.9-1/debian/rules.real#L586Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>