bpfilter_umh is built for the default machine bit of the compiler,
which may not match to the bit size of the kernel.
This happens in the scenario below:
You can use biarch GCC that defaults to 64-bit for building the 32-bit
kernel. In this case, Kbuild passes -m32 to teach the compiler to
produce 32-bit kernel space objects. However, it is missing when
building bpfilter_umh. It is built as a 64-bit ELF, and then embedded
into the 32-bit kernel.
The 32-bit kernel and 64-bit umh is a bad combination.
In theory, we can have 32-bit umh running on 64-bit kernel, but we do
not have a good reason to support such a usecase.
The best is to match the bit size between them.
Pass -m32 or -m64 to the umh build command if it is found in
$(KBUILD_CFLAGS). Evaluate CC_CAN_LINK against the kernel bit-size.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This omits system headers from the generated header dependency.
System headers are not updated unless you upgrade the compiler. Nor do
they contain CONFIG options, so fixdep does not need to parse them.
Having said that, the effect of this optimization will be quite small
because the kernel code generally does not include system headers
except <stdarg.h>. Host programs include a lot of system headers,
but there are not so many in the kernel tree.
At first, keeping system headers in .*.cmd files might be useful to
detect the compiler update, but there is no guarantee that <stdarg.h>
is included from every file. So, I implemented a more reliable way in
the previous commit.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Even though INITRAMFS_SOURCE kconfig option isn't set in most of
defconfigs it is used (set) extensively by various build systems.
Commit f26661e127 ("initramfs: make initramfs compression choice
non-optional") has changed default compression mode. Previously we
compress initramfs using available compression algorithm. Now
we don't use any compression at all by default.
It significantly increases the image size in case of build system
chooses embedded initramfs. Initially I faced with this issue while
using buildroot.
As of today it's not possible to set preferred compression mode
in target defconfig as this option depends on INITRAMFS_SOURCE
being set. Modification of all build systems either doesn't look
like good option.
Let's instead rewrite initramfs compression mode choices list
the way that "INITRAMFS_COMPRESSION_NONE" will be the last option
in the list. In that case it will be chosen only if all other
options (which implements any compression) are not available.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull more Kbuild updates from Masahiro Yamada:
- fix randconfig to generate a sane .config
- rename hostprogs-y / always to hostprogs / always-y, which are more
natual syntax.
- optimize scripts/kallsyms
- fix yes2modconfig and mod2yesconfig
- make multiple directory targets ('make foo/ bar/') work
* tag 'kbuild-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: make multiple directory targets work
kconfig: Invalidate all symbols after changing to y or m.
kallsyms: fix type of kallsyms_token_table[]
scripts/kallsyms: change table to store (strcut sym_entry *)
scripts/kallsyms: rename local variables in read_symbol()
kbuild: rename hostprogs-y/always to hostprogs/always-y
kbuild: fix the document to use extra-y for vmlinux.lds
kconfig: fix broken dependency in randconfig-generated .config
Since commit ddd09bcc89 ("initramfs: make compression options not
depend on INITRAMFS_SOURCE"), Kconfig asks the compression mode for
the built-in initramfs regardless of INITRAMFS_SOURCE.
It is technically simpler, but pointless from a UI perspective,
Linus says [1].
When INITRAMFS_SOURCE is empty, usr/Makefile creates a tiny default
cpio, which is so small that nobody cares about the compression.
This commit hides the Kconfig choice in that case. The default cpio
is embedded without compression, which was the original behavior.
[1]: https://lkml.org/lkml/2020/2/1/160
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.
It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.
This commit renames like follows:
always -> always-y
hostprogs-y -> hostprogs
So, scripts/Makefile will look like this:
always-$(CONFIG_BUILD_BIN2C) += ...
always-$(CONFIG_KALLSYMS) += ...
...
hostprogs := $(always-y) $(always-m)
I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.
The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This script sets the -e option, so it exits on any error, in which
case it exits without cleaning up the intermediate cpio_list.
Make sure to delete it on exit.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, usr/gen_initramfs.sh takes care of all the use-cases:
[1] generates a cpio file unless CONFIG_INITRAMFS_SOURCE points to
a single cpio archive
[2] If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive,
use it as-is.
[3] Compress the cpio file according to CONFIG_INITRAMFS_COMPRESSION_*
unless it is passed a compressed archive.
To simplify the script, move [2] and [3] to usr/Makefile.
If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive, there is
no need to run this shell script.
For the cpio archive compression, you can re-use the rules from
scripts/Makefile.lib .
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, this script outputs a cpio file when -o option is
given, but otherwise a text file in the format recognized by
gen_init_cpio.
This behavior is unclear. Make it always output a cpio file.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When CONFIG_INITRAMFS_SOURCE is empty, the Makefile passes the -d
option to gen_initramfs.sh to create the default initramfs, which
contains /dev, /dev/console, and /root.
This commit simplifies the default behavior; remove the -d option,
and add the default cpio list.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, this script is run twice, for the dependency list, and then
for the cpio archive.
The first one is re-run every time although its build log is suppressed
so nobody notices it.
Make it work more efficiently by generating the cpio and the dependency
list at the same time.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, the choice of the initramfs compression mode is too complex
because users are allowed to not specify the compression mode at all.
I think it makes more sense to require users to choose the compression
mode explicitly, and delete the fallback defaults of INITRAMFS_COMPRESSION.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Even if INITRAMFS_SOURCE is empty, usr/gen_initramfs.sh generates a
tiny default initramfs, which is embedded in vmlinux.
So, defining INITRAMFS_COMPRESSION* options should be valid irrespective
of INITRAMFS_SOURCE.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
init/Kconfig includes usr/Kconfig inside the "if BLK_DEV_INITRD" ...
"endif" block:
if BLK_DEV_INITRD
source "usr/Kconfig"
endif
Hence, all the defines in usr/Kconfig depend on BLK_DEV_INITRD.
Remove the redundant "depends on BLK_DEV_INITRD".
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Greg Thelen <gthelen@google.com>
The comments in usr/Makefile wrongly refer to the script name (twice).
Line 37:
# The dependency list is generated by gen_initramfs.sh -l
Line 54:
# 4) Arguments to gen_initramfs.sh changes
There does not exist such a script.
I was going to fix the comments, but after some consideration, I thought
"gen_initramfs.sh" would be more suitable than "gen_initramfs_list.sh"
because it generates an initramfs image in the common usage.
The script generates a list that can be fed to gen_init_cpio only when
it is directly run without -o or -l option.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
There is no tool named "gen_initramfs". The correct name is
"gen_init_cpio".
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Greg Thelen <gthelen@google.com>
'klibcdirs' was added by commit d39a206bc3 ("kbuild: rebuild initramfs
if content of initramfs changes"). If this is just a matter of forcing
execution of the recipe line, we can replace it with FORCE.
The following code is currently useless:
$(deps_initramfs): klibcdirs
The original intent could be a hook for the klibc integration into the
kernel tree, but klibc is a separate project, which can be built
independently. Clean it up.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Greg Thelen <gthelen@google.com>
Since commit d2a99dbdad ("kbuild: update compile-test header list for
v5.5-rc1"), this does not depend on any CONFIG option.
no-header-test is clearer.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Adding an include guard to every header file is good practice in case
it is included multiple times.
Exported headers are compile-tested for the comprehensive sanity checks.
Let's include the same header twice. If an include guard is missing,
the header will fail to build due to redefinition of something.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Prior to commit 858805b336 ("kbuild: add $(BASH) to run scripts with
bash-extension"), this shell script was almost always run by bash since
bash is usually installed on the system by default.
Now, this script is run by sh, which might be a symlink to dash. On such
distributions, the following code emits an error:
local dev=`LC_ALL=C ls -l "${location}"`
You can reproduce the build error, for example by setting
CONFIG_INITRAMFS_SOURCE="/dev".
GEN usr/initramfs_data.cpio.gz
./usr/gen_initramfs_list.sh: 131: local: 1: bad variable name
make[1]: *** [usr/Makefile:61: usr/initramfs_data.cpio.gz] Error 2
This is because `LC_ALL=C ls -l "${location}"` contains spaces.
Surrounding it with double-quotes fixes the error.
Fixes: 858805b336 ("kbuild: add $(BASH) to run scripts with bash-extension")
Reported-by: Jory A. Pratt <anarchy@gentoo.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
