kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/

kernel.spec is the last piece that resides outside the rpmbuild/
directory. Move all the RPM-related files to rpmbuild/ consistently.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>

kbuild: rpm-pkg: rename binkernel.spec to kernel.spec

Now kernel.spec and binkernel.spec have the exactly same contents.

Use kernel.spec for binrpm-pkg as well.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion

When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.

Linus stated negative opinions about this slowness in commits:

- 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option")
- a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding")

We can do this better now. The final data structures of EXPORT_SYMBOL
are generated by the modpost stage, so modpost can selectively emit
KSYMTAB entries that are really used by modules.

Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another
ground-work to do this in a one-pass algorithm. With the list of modules,
modpost sets sym->used if it is used by a module. modpost emits KSYMTAB
only for symbols with sym->used==true.

BTW, Nicolas explained why the trimming was implemented with recursion:

https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/

Actually, we never achieved that level of optimization where the chain
reaction of trimming comes into play because:

- CONFIG_LTO_CLANG cannot remove any unused symbols
- CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux,
but not modules

If deeper trimming is required, we need to revisit this, but I guess
that is unlikely to happen.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: do not put .scmversion into the source tarball

.scmversion is used by (src)rpm-pkg and deb-pkg to carry KERNELRELEASE.

In fact, deb-pkg does not rely on it any more because the generated
debian/rules specifies KERNELRELEASE from the command line.

Do likwise for (src)rpm-pkg, and remove this feature.
For the same reason, you do not need to save LOCALVERSION in the
spec file.

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

scripts: remove bin2c

Commit 80f8be7af03f ("tomoyo: Omit use of bin2c") removed the last
use of bin2c.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>

kbuild: rust: move rust/target.json to scripts/

scripts/ is a better place to generate files used treewide.

With target.json moved to scripts/, you do not need to add target.json
to no-clean-files or MRPROPER_FILES.

'make clean' does not visit scripts/, but 'make mrproper' does.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>

kbuild: clean up stale file removal

More than one year has passed since the copied *.[cS] files were
removed from arch/*/boot/compressed/.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kconfig: refactor Makefile to reduce process forks

Refactor Makefile and use read-file macro. For Make >= 4.2, it can read
out a file by using the built-in function.

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

riscv/purgatory: Omit use of bin2c

The .incbin assembler directive is much faster than bin2c + $(CC).

Do similar refactoring as in commit 4c0f032d4963 ("s390/purgatory:
Omit use of bin2c").

Please note the .quad directive matches to size_t in C (both 8 byte)
because the purgatory is compiled only for the 64-bit kernel.
(KEXEC_FILE depends on 64BIT).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20220625223438.835408-2-masahiroy@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

powerpc/purgatory: Omit use of bin2c

The .incbin assembler directive is much faster than bin2c + $(CC).

Do similar refactoring as in commit 4c0f032d4963 ("s390/purgatory:
Omit use of bin2c").

Please note the .quad directive matches to size_t in C (both 8 byte)
because the purgatory is compiled only for the 64-bit kernel.
(KEXEC_FILE depends on PPC64).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220725015619.618070-1-masahiroy@kernel.org

x86/purgatory: Omit use of bin2c

The .incbin assembler directive is much faster than bin2c + $(CC).

Do similar refactoring as in

4c0f032d4963 ("s390/purgatory: Omit use of bin2c").

Please note the .quad directive matches to size_t in C (both 8
byte) because the purgatory is compiled only for the 64-bit kernel.
(KEXEC_FILE depends on X86_64).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220725020812.622255-2-masahiroy@kernel.org

certs: move scripts/extract-cert to certs/

extract-cert is only used in certs/Makefile.

Move it there and build extract-cert on demand.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

parisc: decompressor: do not copy source files while building

As commit 7ae4a78daacf ("ARM: 8969/1: decompressor: simplify libfdt
builds") stated, copying source files during the build time may not
end up with as clean code as expected.

Do similar for parisc to clean up the Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>

ARM: 9154/1: decompressor: do not copy source files while building

As commit 7ae4a78daacf ("ARM: 8969/1: decompressor: simplify libfdt
builds") stated, copying source files during the build time may not
end up with as clean code as expected.

Do similar for the other library files for further cleanups of the
Makefile and .gitignore.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

mips: decompressor: do not copy source files while building

As commit 7ae4a78daacf ("ARM: 8969/1: decompressor: simplify libfdt
builds") stated, copying source files during the build time may not
end up with as clean code as expected.

Do similar for mips to clean up the Makefile and .gitignore.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

kbuild: add a script to remove stale generated files

We maintain .gitignore and Makefiles so build artifacts are properly
ignored by Git, and cleaned up by 'make clean'. However, the code is
always changing; generated files are often moved to another directory,
or removed when they become unnecessary. Such garbage files tend to be
left over in the source tree because people usually git-pull without
cleaning the tree.

This is not only the noise for 'git status', but also a build issue
in some cases.

One solution is to remove a stale file like commit 223c24a7dba9 ("kbuild:
Automatically remove stale <linux/version.h> file") did. Such workaround
should be removed after a while, but we forget about that if we scatter
the workaround code in random places.

So, this commit adds a new script to collect cleanings of stale files.

As a start point, move the code in arch/arm/boot/compressed/Makefile
into this script.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>