| Age | Commit message (Collapse) | Author |
|---|
|
-fmacro-prefix-map only affects __FILE__ and __BASE_FILE__.
Other references, for example in debug information, are not affected.
This makes handling of file references in the compiler outputs harder to
use and creates problems for reproducible builds.
Switch to -ffile-prefix map which affects all references.
Also drop the documentation section advising manual specification of
-fdebug-prefix-map for reproducible builds, as it is not necessary
anymore.
Suggested-by: Ben Hutchings <ben@decadent.org.uk>
Link: https://lore.kernel.org/lkml/c49cc967294f9a3a4a34f69b6a8727a6d3959ed8.camel@decadent.org.uk/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Correct the indentation in an example within the `modules.rst` file
to improve readability.
Signed-off-by: Kefan Liu <liukefan24s@ict.ac.cn>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Kernel build commands can sometimes be long, particularly when
cross-compiling, making them tedious to type and prone to mistypes.
This commit introduces bash completion support for common variables
and targets in Kbuild.
For installation instructions, please refer to the documentation in
Documentation/kbuild/bash-completion.rst.
The following examples demonstrate how this saves typing.
[Example 1] a long command line for cross-compiling
$ make A<TAB>
-> completes 'A' to 'ARCH='
$ make ARCH=<TAB>
-> displays all supported architectures
$ make ARCH=arm64 CR<TAB>
-> completes 'CR' to 'CROSS_COMPILE='
$ make ARCH=arm64 CROSS_COMPILE=<TAB>
-> displays installed toolchains
$ make ARCH=arm64 CROSS_COMPILE=aa<TAB>
-> completes 'CROSS_COMPILE=aa' to 'CROSS_COMPILE=aarch64-linux-gnu-'
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- def<TAB>
-> completes 'def' to 'defconfig'
[Example 2] a single build target
$ make f<TAB>
-> completes 'f' to 'fs/'
$ make fs/<TAB>
-> displays objects and sub-directories in fs/
$ make fs/xf<TAB>
-> completes 'fs/xf' to 'fs/xfs/'
$ make fs/xfs/l<TAB>
-> completes 'fs/xfs/l' to 'fs/xfs/libxfs/xfs_'
$ make fs/xfs/libxfs/xfs_g<TAB>
-> completes 'fs/xfs/libxfs/xfs_g' to 'fs/xfs/libxfs/xfs_group.o'
This does not aim to provide a complete list of variables and targets,
as there are too many. However, it covers variables and targets used
in common scenarios, and I hope this is useful enough.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Tested-by: Nicolas Schier <n.schier@avm.de>
|
|
Several drivers express optional Kconfig dependency with FOO || !FOO,
but for many choices this is not suitable: lack of stubs for !FOO
like in HWMON. Describe the second, less favorable way of optional
dependency with IS_REACHABLE by moving the code from "imply" chapter to
"Optional dependencies".
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Introduce `rustc-min-version` support function that mimics
`{gcc,clang}-min-version` ones, following commit 88b61e3bff93
("Makefile.compiler: replace cc-ifversion with compiler-specific macros").
In addition, use it in the first use case we have in the kernel (which
was done independently to minimize the changes needed for the fix).
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Fiona Behrens <me@Kloenk.dev>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Commit f77bf01425b1 ("kbuild: introduce ccflags-y, asflags-y and
ldflags-y") deprecated these in 2007. The migration should have been
completed by now.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Support multiple hook locations for maint scripts of Debian package
- Remove 'cpio' from the build tool requirement
- Introduce gendwarfksyms tool, which computes CRCs for export symbols
based on the DWARF information
- Support CONFIG_MODVERSIONS for Rust
- Resolve all conflicts in the genksyms parser
- Fix several syntax errors in genksyms
* tag 'kbuild-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (64 commits)
kbuild: fix Clang LTO with CONFIG_OBJTOOL=n
kbuild: Strip runtime const RELA sections correctly
kconfig: fix memory leak in sym_warn_unmet_dep()
kconfig: fix file name in warnings when loading KCONFIG_DEFCONFIG_LIST
genksyms: fix syntax error for attribute before init-declarator
genksyms: fix syntax error for builtin (u)int*x*_t types
genksyms: fix syntax error for attribute after 'union'
genksyms: fix syntax error for attribute after 'struct'
genksyms: fix syntax error for attribute after abstact_declarator
genksyms: fix syntax error for attribute before nested_declarator
genksyms: fix syntax error for attribute before abstract_declarator
genksyms: decouple ATTRIBUTE_PHRASE from type-qualifier
genksyms: record attributes consistently for init-declarator
genksyms: restrict direct-declarator to take one parameter-type-list
genksyms: restrict direct-abstract-declarator to take one parameter-type-list
genksyms: remove Makefile hack
genksyms: fix last 3 shift/reduce conflicts
genksyms: fix 6 shift/reduce conflicts and 5 reduce/reduce conflicts
genksyms: reduce type_qualifier directly to decl_specifier
genksyms: rename cvar_qualifier to type_qualifier
...
|
|
These are flags to be passed when linking proc macros for the Rust
toolchain. If unset, it defaults to $(KBUILD_HOSTLDFLAGS).
This is needed because the list of flags to link hostprogs is not
necessarily the same as the list of flags used to link libmacros.so.
When we build proc macros, we need the latter, not the former (e.g. when
using a Rust compiler binary linked to a different C library than host
programs).
To distinguish between the two, introduce this new variable to stand
out from KBUILD_HOSTLDFLAGS used to link other host progs.
Signed-off-by: HONG Yifan <elsk@google.com>
Link: https://lore.kernel.org/r/20241017210430.2401398-2-elsk@google.com
[ v3:
- `export`ed the variable. Otherwise it would not be visible in
`rust/Makefile`.
- Removed "additional" from the documentation and commit message,
since this actually replaces the other flags, unlike other cases.
- Added example of use case to documentation and commit message.
Thanks Alice for the details on what Google needs!
- Instead of `HOSTLDFLAGS`, used `KBUILD_HOSTLDFLAGS` as the fallback
to preserve the previous behavior as much as possible, as discussed
with Alice/Yifan. Thus moved the variable down too (currently we
do not modify `KBUILD_HOSTLDFLAGS` elsewhere) and avoided
mentioning `HOSTLDFLAGS` directly in the documentation.
- Fixed documentation header formatting.
- Reworded slightly.
- Miguel ]
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: HONG Yifan <elsk@google.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20241112184455.855133-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
|
|
Document where exported and imported symbols are kept, format options,
and limitations.
Signed-off-by: Matthew Maurer <mmaurer@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Add documentation for gendwarfksyms changes, and the kABI stability
features that can be useful for distributions even though they're not
used in mainline kernels.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Add generic support for built-in boot DTB files
- Enable TAB cycling for dialog buttons in nconfig
- Fix issues in streamline_config.pl
- Refactor Kconfig
- Add support for Clang's AutoFDO (Automatic Feedback-Directed
Optimization)
- Add support for Clang's Propeller, a profile-guided optimization.
- Change the working directory to the external module directory for M=
builds
- Support building external modules in a separate output directory
- Enable objtool for *.mod.o and additional kernel objects
- Use lz4 instead of deprecated lz4c
- Work around a performance issue with "git describe"
- Refactor modpost
* tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits)
kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms
gitignore: Don't ignore 'tags' directory
kbuild: add dependency from vmlinux to resolve_btfids
modpost: replace tdb_hash() with hash_str()
kbuild: deb-pkg: add python3:native to build dependency
genksyms: reduce indentation in export_symbol()
modpost: improve error messages in device_id_check()
modpost: rename alias symbol for MODULE_DEVICE_TABLE()
modpost: rename variables in handle_moddevtable()
modpost: move strstarts() to modpost.h
modpost: convert do_usb_table() to a generic handler
modpost: convert do_of_table() to a generic handler
modpost: convert do_pnp_device_entry() to a generic handler
modpost: convert do_pnp_card_entries() to a generic handler
modpost: call module_alias_printf() from all do_*_entry() functions
modpost: pass (struct module *) to do_*_entry() functions
modpost: remove DEF_FIELD_ADDR_VAR() macro
modpost: deduplicate MODULE_ALIAS() for all drivers
modpost: introduce module_alias_printf() helper
modpost: remove unnecessary check in do_acpi_entry()
...
|
|
Unless an explicit O= option is provided, external module builds must
start from the kernel directory.
This can be achieved by using the -C option:
$ make -C /path/to/kernel M=/path/to/external/module
This commit allows starting external module builds from any directory,
so you can also do the following:
$ make -f /path/to/kernel/Makefile M=/path/to/external/module
The key difference is that the -C option changes the working directory
and parses the Makefile located there, while the -f option only
specifies the Makefile to use.
As shown in the examples in Documentation/kbuild/modules.rst, external
modules usually have a wrapper Makefile that allows you to build them
without specifying any make arguments. The Makefile typically contains
a rule as follows:
KDIR ?= /path/to/kernel
default:
$(MAKE) -C $(KDIR) M=$(CURDIR) $(MAKECMDGOALS)
The log will appear as follows:
$ make
make -C /path/to/kernel M=/path/to/external/module
make[1]: Entering directory '/path/to/kernel'
make[2]: Entering directory '/path/to/external/module'
CC [M] helloworld.o
MODPOST Module.symvers
CC [M] helloworld.mod.o
CC [M] .module-common.o
LD [M] helloworld.ko
make[2]: Leaving directory '/path/to/external/module'
make[1]: Leaving directory '/path/to/kernel'
This changes the working directory twice because the -C option first
switches to the kernel directory, and then Kbuild internally recurses
back to the external module directory.
With this commit, the wrapper Makefile can directly include the kernel
Makefile:
KDIR ?= /path/to/kernel
export KBUILD_EXTMOD := $(realpath $(dir $(lastword $(MAKEFILE_LIST))))
include $(KDIR)/Makefile
This avoids unnecessary sub-make invocations:
$ make
CC [M] helloworld.o
MODPOST Module.symvers
CC [M] helloworld.mod.o
CC [M] .module-common.o
LD [M] helloworld.ko
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
|
|
There has been a long-standing request to support building external
modules in a separate build directory.
This commit introduces a new environment variable, KBUILD_EXTMOD_OUTPUT,
and its shorthand Make variable, MO.
A simple usage:
$ make -C <kernel-dir> M=<module-src-dir> MO=<module-build-dir>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
|
|
Currently, Kbuild always operates in the output directory of the kernel,
even when building external modules. This increases the risk of external
module Makefiles attempting to write to the kernel directory.
This commit switches the working directory to the external module
directory, allowing the removal of the $(KBUILD_EXTMOD)/ prefix from
some build artifacts.
The command for building external modules maintains backward
compatibility, but Makefiles that rely on working in the kernel
directory may break. In such cases, $(objtree) and $(srctree) should
be used to refer to the output and source directories of the kernel.
The appearance of the build log will change as follows:
[Before]
$ make -C /path/to/my/linux M=/path/to/my/externel/module
make: Entering directory '/path/to/my/linux'
CC [M] /path/to/my/externel/module/helloworld.o
MODPOST /path/to/my/externel/module/Module.symvers
CC [M] /path/to/my/externel/module/helloworld.mod.o
CC [M] /path/to/my/externel/module/.module-common.o
LD [M] /path/to/my/externel/module/helloworld.ko
make: Leaving directory '/path/to/my/linux'
[After]
$ make -C /path/to/my/linux M=/path/to/my/externel/module
make: Entering directory '/path/to/my/linux'
make[1]: Entering directory '/path/to/my/externel/module'
CC [M] helloworld.o
MODPOST Module.symvers
CC [M] helloworld.mod.o
CC [M] .module-common.o
LD [M] helloworld.ko
make[1]: Leaving directory '/path/to/my/externel/module'
make: Leaving directory '/path/to/my/linux'
Printing "Entering directory" twice is cumbersome. This will be
addressed later.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
clang only supports building 64-bit kernel, so we use the
sparc64-linux-gnu target.
See also: https://lore.kernel.org/lkml/e26PTXUXEz8OYXmaeKn4Mpuejr4IOlFfFwdB5vpsluXlYiqDdlyQTYcDtdAny_o4gO4SfPeQCCN2qpyT6e0nog5EaP3xk2SeUPTrF54p1gM=@protonmail.com/T/#m068e010dcf8b99d3510a90d7532bcdb70e2e2c6b
Signed-off-by: Koakuma <koachan@protonmail.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Link: https://lore.kernel.org/r/20241029-sparc-cflags-v3-2-b28745a6bd71@protonmail.com
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
|
|
Since commit fde192511bdb ("kconfig: remove tristate choice support"),
all choice blocks are now boolean. There is no longer a need to specify
the choice type explicitly.
All "bool" prompts in choice entries have been converted to "prompt".
This commit removes support for the "bool" syntax in choice entries.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Avoid "gcc" since it is not the only compiler supported by Kbuild.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
Building external modules is typically done using this command:
$ make -C <KERNEL_DIR> M=<EXTMOD_DIR>
Here, <KERNEL_DIR> refers to the output directory where the kernel was
built, not the kernel source directory.
When the kernel is built in the source tree, there is no ambiguity, as
the output directory and the source directory are the same.
If the kernel was built in a separate build directory, <KERNEL_DIR>
should be the kernel output directory. Otherwise, Kbuild cannot locate
necessary build artifacts. This has been the method for building
external modules against a pre-built kernel in a separate directory
for over 20 years. [1]
If you pass the kernel source directory to the -C option, you must also
specify the kernel build directory using the O= option. This approach
works as well, though it results in a slightly longer command:
$ make -C <KERNEL_SOURCE_DIR> O=<KERNEL_BUILD_DIR> M=<EXTMOD_DIR>
Some people mistakenly believe that O= should specify a build directory
for external modules when used together with M=. This commit adds more
clarification to Documentation/kbuild/kbuild.rst.
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=e321b2ec2eb2993b3d0116e5163c78ad923e3c54
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
The use of shipped files is discouraged in the upstream kernel these
days. [1]
Downstream Makefiles have the freedom to use shipped files or other
options to handle binaries, but this should not be advertised in the
upstream document.
[1]: https://lore.kernel.org/all/CAHk-=wgSEi_ZrHdqr=20xv+d6dr5G895CbOAi8ok+7-CQUN=fQ@mail.gmail.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
Do similar to commit 1a4c1c9df72e ("docs/kbuild/makefiles: drop section
numbering, use references").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Do similar to commit 5e8f0ba38a4d ("docs/kbuild/makefiles: throw out the
local table of contents").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Kbuild used to manipulate header search paths, enforcing the odd
limitation of "no space after -I".
Commit cdd750bfb1f7 ("kbuild: remove 'addtree' and 'flags' magic for
header search paths") stopped doing that. This limitation no longer
exists. Instead, you need to accurately specify the header search path.
(In this case, $(src)/include)
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
This description was added 20 years ago [1]. It does not convey any
useful information except for a feeling of nostalgia.
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=65e433436b5794ae056d22ddba60fe9194bba007
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
The phrase "In newer versions of the kernel" was added 14 years ago, by
commit efdf02cf0651 ("Documentation/kbuild: major edit of modules.txt
sections 1-4"). This feature is no longer new, so remove it and update
the paragraph.
Example 3 was written 20 years ago [1]. There is no need to note about
backward compatibility with such an old build system. Remove Example 3
entirely.
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=65e433436b5794ae056d22ddba60fe9194bba007
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
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>
|
|
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>
|
|
The command provided to use ccache with clang is not a literal code
block. Once built, the documentation displays the '' symbols as a "
character, which is wrong, and the command can not be applied as
provided.
Turn the command into a literal code block.
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
In this part of the documentation, $(CC) is meant, but gcc is written.
Signed-off-by: Ivan Davydov <davydoff33@yandex.ru>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
I previously submitted a fix for a bug in the choice feature [1], where
I mentioned, "Another (much cleaner) approach would be to remove the
tristate choice support entirely".
There are more issues in the tristate choice feature. For example, you
can observe a couple of bugs in the following test code.
[Test Code]
config MODULES
def_bool y
modules
choice
prompt "tristate choice"
default A
config A
tristate "A"
config B
tristate "B"
endchoice
Bug 1: the 'default' property is not correctly processed
'make alldefconfig' produces:
CONFIG_MODULES=y
# CONFIG_A is not set
# CONFIG_B is not set
However, the correct output should be:
CONFIG_MODULES=y
CONFIG_A=y
# CONFIG_B is not set
The unit test file, scripts/kconfig/tests/choice/alldef_expected_config,
is wrong as well.
Bug 2: choice members never get 'y' with randconfig
For the test code above, the following combinations are possible:
A B
(1) y n
(2) n y
(3) m m
(4) m n
(5) n m
(6) n n
'make randconfig' never produces (1) or (2).
These bugs are fixable, but a more critical problem is the lack of a
sensible syntax to specify the default for the tristate choice.
The default for the choice must be one of the choice members, which
cannot specify any of the patterns (3) through (6) above.
In addition, I have never seen it being used in a useful way.
The following commits removed unnecessary use of tristate choices:
- df8df5e4bc37 ("usb: get rid of 'choice' for legacy gadget drivers")
- bfb57ef0544a ("rapidio: remove choice for enumeration")
This commit removes the tristate choice support entirely, which allows
me to delete a lot of code, making further refactoring easier.
Note:
This includes the revert of commit fa64e5f6a35e ("kconfig/symbol.c:
handle choice_values that depend on 'm' symbols"). It was suspicious
because it did not address the root cause but introduced inconsistency
in visibility between choice members and other symbols.
[1]: https://lore.kernel.org/linux-kbuild/20240427104231.2728905-1-masahiroy@kernel.org/T/#m0a1bb6992581462ceca861b409bb33cb8fd7dbae
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
|
|
The default INSTALL_MOD_DIR was changed from 'extra' to
'updates' in commit b74d7bb7ca24 ("kbuild: Modify default
INSTALL_MOD_DIR from extra to updates").
This commit updates the documentation to align with the
latest kernel.
Fixes: b74d7bb7ca24 ("kbuild: Modify default INSTALL_MOD_DIR from extra to updates")
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Documentation/kbuild/kconfig-language.rst explains the behavior of
'select' as follows:
reverse dependencies can be used to force a lower limit of
another symbol. The value of the current menu symbol is used as the
minimal value <symbol> can be set to.
This is not true when the 'select' property is followed by 'if'.
[Test Code]
config MODULES
def_bool y
modules
config A
def_tristate y
select C if B
config B
def_tristate m
config C
tristate
[Result]
CONFIG_MODULES=y
CONFIG_A=y
CONFIG_B=m
CONFIG_C=m
If "the value of A is used as the minimal value C can be set to",
C must be 'y'.
The actual behavior is "C is selected by (A && B)". The lower limit of
C is downgraded due to B being 'm'.
This behavior is kind of weird, and this has arisen several times in
the mailing list.
I do not know whether it is a bug or intended behavior. Anyway, it is
not feasible to change it now because many Kconfig files are written
based on this behavior. The same applies to 'imply'.
Document this (but reserve the possibility for a future change).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
|
|
This sentence does not make sense due to a typo. Fix it.
Fixes: def2fbffe62c ("kconfig: allow symbols implied by y to become m")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
|
|
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>
|
|
The 'choice' statement is primarily used to exclusively select one
option, but the 'optional' property allows all entries to be disabled.
In the following example, both A and B can be disabled simultaneously:
choice
prompt "choose A, B, or nothing"
optional
config A
bool "A"
config B
bool "B"
endchoice
You can achieve the equivalent outcome by other means.
A common solution is to add another option to guard the choice block.
In the following example, you can set ENABLE_A_B_CHOICE=n to disable
the entire choice block:
choice
prompt "choose A or B"
depends on ENABLE_A_B_CHOICE
config A
bool "A"
config B
bool "B"
endchoice
Another approach is to insert one more entry:
choice
prompt "choose A, B, or disable both"
config A
bool "A"
config B
bool "B"
config DISABLE_A_AND_B
bool "choose this to disable both A and B"
endchoice
Some real examples are DEBUG_INFO_NONE, INITRAMFS_COMPRESSION_NONE,
LTO_NONE, etc.
The 'optional' property is even more unnecessary for a tristate choice.
Without the 'optional' property, you can disable A and B; you can set
'm' in the choice prompt, and disable A and B individually:
choice
prompt "choose one built-in or make them modular"
config A
tristate "A"
config B
tristate "B"
endchoice
In conclusion, the 'optional' property was unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
|
|
As of the first s390 pull request during the 6.9 merge window,
commit 691632f0e869 ("Merge tag 's390-6.9-1' of
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux"), s390 can be
built with LLVM=1 when using LLVM 18.1.0, which is the first version
that has SystemZ support implemented in ld.lld and llvm-objcopy.
Update the supported architectures table in the Kbuild LLVM
documentation to note this explicitly to make it more discoverable by
users and other developers. Additionally, this brings s390 in line with
the rest of the architectures in the table, which all support LLVM=1.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Commit 5a1aa8a1aff6 ("kconfig: add named choice group") did not provide
enough explanation regarding its benefits. A use case was found in
another project [1] sometime later, this feature has never been used in
the kernel.
[1]: https://lore.kernel.org/all/201012150034.01356.yann.morin.1998@anciens.enib.fr/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
|
|
This document was using headings in an odd way, causing the sidebar to be
quite messy. I've adding new headings and turned some of the old headings
into description lists.
The indentation was a mix of spaces and tabs; I've turned them all into
4 spaces so it always reads correctly regardless of tab settings.
Also use ``...`` instead of `...`; the difference is that `` is meant
for "inline literals" (and renders in a monospace font) while ` is for
"interpreted text" (and renders with italics).
Also changed the title of the document to be more descriptive.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
- Remove unnecessary spaces
- Fix grammar s/to solution/solution/
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Implement the binary search in modpost for faster symbol lookup
- Respect HOSTCC when linking host programs written in Rust
- Change the binrpm-pkg target to generate kernel-devel RPM package
- Fix endianness issues for tee and ishtp MODULE_DEVICE_TABLE
- Unify vdso_install rules
- Remove unused __memexit* annotations
- Eliminate stale whitelisting for __devinit/__devexit from modpost
- Enable dummy-tools to handle the -fpatchable-function-entry flag
- Add 'userldlibs' syntax
* tag 'kbuild-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits)
kbuild: support 'userldlibs' syntax
kbuild: dummy-tools: pretend we understand -fpatchable-function-entry
kbuild: Correct missing architecture-specific hyphens
modpost: squash ALL_{INIT,EXIT}_TEXT_SECTIONS to ALL_TEXT_SECTIONS
modpost: merge sectioncheck table entries regarding init/exit sections
modpost: use ALL_INIT_SECTIONS for the section check from DATA_SECTIONS
modpost: disallow the combination of EXPORT_SYMBOL and __meminit*
modpost: remove EXIT_SECTIONS macro
modpost: remove MEM_INIT_SECTIONS macro
modpost: remove more symbol patterns from the section check whitelist
modpost: disallow *driver to reference .meminit* sections
linux/init: remove __memexit* annotations
modpost: remove ALL_EXIT_DATA_SECTIONS macro
kbuild: simplify cmd_ld_multi_m
kbuild: avoid too many execution of scripts/pahole-flags.sh
kbuild: remove ARCH_POSTLINK from module builds
kbuild: unify no-compiler-targets and no-sync-config-targets
kbuild: unify vdso_install rules
docs: kbuild: add INSTALL_DTBS_PATH
UML: remove unused cmd_vdso_install
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull ia64 removal and asm-generic updates from Arnd Bergmann:
- The ia64 architecture gets its well-earned retirement as planned,
now that there is one last (mostly) working release that will be
maintained as an LTS kernel.
- The architecture specific system call tables are updated for the
added map_shadow_stack() syscall and to remove references to the
long-gone sys_lookup_dcookie() syscall.
* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
hexagon: Remove unusable symbols from the ptrace.h uapi
asm-generic: Fix spelling of architecture
arch: Reserve map_shadow_stack() syscall number for all architectures
syscalls: Cleanup references to sys_lookup_dcookie()
Documentation: Drop or replace remaining mentions of IA64
lib/raid6: Drop IA64 support
Documentation: Drop IA64 from feature descriptions
kernel: Drop IA64 support from sig_fault handlers
arch: Remove Itanium (IA-64) architecture
|
|
This syntax is useful to specify libraries linked to all userspace
programs in the Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
The documentation for kbuild and makefiles is missing an explanation of
a variable important for some architectures.
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
This problem frequently comes up in randconfig testing, with
drivers failing to link because of a dependency on an optional
feature.
The Kconfig language for this is very confusing, so try to
document it in "Kconfig hints" section.
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Drop or update mentions of IA64, as appropriate.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Enable -Wenum-conversion warning option
- Refactor the rpm-pkg target
- Fix scripts/setlocalversion to consider annotated tags for rt-kernel
- Add a jump key feature for the search menu of 'make nconfig'
- Support Qt6 for 'make xconfig'
- Enable -Wformat-overflow, -Wformat-truncation, -Wstringop-overflow,
and -Wrestrict warnings for W=1 builds
- Replace <asm/export.h> with <linux/export.h> for alpha, ia64, and
sparc
- Support DEB_BUILD_OPTIONS=parallel=N for the debian source package
- Refactor scripts/Makefile.modinst and fix some modules_sign issues
- Add a new Kconfig env variable to warn symbols that are not defined
anywhere
- Show help messages of config fragments in 'make help'
* tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (62 commits)
kconfig: fix possible buffer overflow
kbuild: Show marked Kconfig fragments in "help"
kconfig: add warn-unknown-symbols sanity check
kbuild: dummy-tools: make MPROFILE_KERNEL checks work on BE
Documentation/llvm: refresh docs
modpost: Skip .llvm.call-graph-profile section check
kbuild: support modules_sign for external modules as well
kbuild: support 'make modules_sign' with CONFIG_MODULE_SIG_ALL=n
kbuild: move more module installation code to scripts/Makefile.modinst
kbuild: reduce the number of mkdir calls during modules_install
kbuild: remove $(MODLIB)/source symlink
kbuild: move depmod rule to scripts/Makefile.modinst
kbuild: add modules_sign to no-{compiler,sync-config}-targets
kbuild: do not run depmod for 'make modules_sign'
kbuild: deb-pkg: support DEB_BUILD_OPTIONS=parallel=N in debian/rules
alpha: remove <asm/export.h>
alpha: replace #include <asm/export.h> with #include <linux/export.h>
ia64: remove <asm/export.h>
ia64: replace #include <asm/export.h> with #include <linux/export.h>
sparc: remove <asm/export.h>
...
|
|
Introduce KCONFIG_WARN_UNKNOWN_SYMBOLS environment variable,
which makes Kconfig warn about unknown config symbols.
This is especially useful for continuous kernel uprevs when
some symbols can be either removed or renamed between kernel
releases (which can go unnoticed otherwise).
By default KCONFIG_WARN_UNKNOWN_SYMBOLS generates warnings,
which are non-terminal. There is an additional environment
variable KCONFIG_WERROR that overrides this behaviour and
turns warnings into errors.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Recent fixes for an embargoed hardware security vulnerability failed to
link with ld.lld (LLVM's linker). [0] To be fair, our documentation
mentions ``CC=clang`` foremost with ``LLVM=1`` being buried "below the
fold."
We want to encourage the use of ``LLVM=1`` rather than just
``CC=clang``. Make that suggestion "above the fold" and "front and
center" in our docs.
While here, the following additional changes were made:
- remove the bit about CROSS_COMPILE setting --target=, that's no longer
true.
- Add ARCH=loongarch to the list of maintained targets (though we're
still working on getting defconfig building cleanly at the moment;
we're pretty close).
- Bump ARCH=powerpc from CC=clang to LLVM=1 status.
- Promote ARCH=riscv from being Maintained to being Supported. Android
is working towards supporting RISC-V, and we have excellent support
from multiple companies in this regard.
- Note that the toolchain distribution on kernel.org has been built with
profile data from kernel builds.
- Note how to use ccache with clang.
Link: https://github.com/ClangBuiltLinux/linux/issues/1907 [0]
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Menuconfig has a feature where you can "press the key in the (#) prefix
to jump directly to that location. You will be returned to the current
search results after exiting this new menu."
This feature is poorly documented,
so add it to the kconfig.rst documentation.
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Jesse mentioned that gconfig is missing from the top of the
kconfig.rst file, so add it for completeness.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: lore.kernel.org/r/CAJFTR8QgYykuEq_AkODEWPUYXncKgRBHOncxT=ypZTQODkyarw@mail.gmail.com
Cc: Jesse Taube <mr.bossman075@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230704000120.8098-1-rdunlap@infradead.org
|
|
The kernel-doc script currently reports a number of issues
only in "verbose" mode, but that's initialized from V=1
(via KBUILD_VERBOSE), so if you use KDOC_WERROR=1 then
adding V=1 might actually break the build. This is rather
unexpected.
Change kernel-doc to not change its behaviour wrt. errors
(or warnings) when verbose mode is enabled, but rather add
separate warning flags (and -Wall) for it. Allow enabling
those flags via environment/make variables in the kernel's
build system for easier user use, but to not have to parse
them in the script itself.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
