In preparation for Clang stack depth tracking for KSTACK_ERASE,
split the stackleak-specific cflags out of GCC_PLUGINS_CFLAGS into
KSTACK_ERASE_CFLAGS.
Link: https://lore.kernel.org/r/20250717232519.2984886-3-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
In Rust 1.78.0, Clippy introduced the `ref_as_ptr` lint [1]:
> Using `as` casts may result in silently changing mutability or type.
While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize. It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#ref_as_ptr [1]
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/all/D8PGG7NTWB6U.3SS3A5LN4XWMN@proton.me/
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-6-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Before Rust 1.29.0, Clippy introduced the `cast_lossless` lint [1]:
> Rust’s `as` keyword will perform many kinds of conversions, including
> silently lossy conversions. Conversion functions such as `i32::from`
> will only perform lossless conversions. Using the conversion functions
> prevents conversions from becoming silently lossy if the input types
> ever change, and makes it clear for people reading the code that the
> conversion is lossless.
While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize. It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless [1]
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/all/D8ORTXSUTKGL.1KOJAGBM8F8TN@proton.me/
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Acked-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-5-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]:
> The conversion might include lossy conversion or a dangerous cast that
> might go undetected due to the type being inferred.
>
> The lint is allowed by default as using `_` is less wordy than always
> specifying the type.
Always specifying the type is especially helpful in function call
contexts where the inferred type may change at a distance. Specifying
the type also allows Clippy to spot more cases of `useless_conversion`.
The primary downside is the need to specify the type in trivial getters.
There are 4 such functions: 3 have become slightly less ergonomic, 1 was
revealed to be a `useless_conversion`.
While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize. It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com
[ Changed `isize` to `c_long`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust 1.66.0, Clippy introduced the `as_ptr_cast_mut` lint [1]:
> Since `as_ptr` takes a `&self`, the pointer won’t have write
> permissions unless interior mutability is used, making it unlikely
> that having it as a mutable pointer is correct.
There is only one affected callsite, and the change amounts to replacing
`as _` with `.cast_mut().cast()`. This doesn't change the semantics, but
is more descriptive of what's going on.
Apply this change and enable the lint -- no functional change intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_ptr_cast_mut [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-3-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust 1.72.0, Clippy introduced the `ptr_cast_constness` lint [1]:
> Though `as` casts between raw pointers are not terrible,
> `pointer::cast_mut` and `pointer::cast_const` are safer because they
> cannot accidentally cast the pointer to another type.
There are only 3 affected sites:
- `*mut T as *const U as *mut U` becomes `(*mut T).cast()`.
- `&self as *const Self as *mut Self` becomes
`core::ptr::from_ref(self).cast_mut()`.
- `*const T as *mut _` becommes `(*const T).cast_mut()`.
Apply these changes and enable the lint -- no functional change
intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_cast_constness [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-2-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]:
> Though `as` casts between raw pointers are not terrible,
> `pointer::cast` is safer because it cannot accidentally change the
> pointer's mutability, nor cast the pointer to other types like `usize`.
There are a few classes of changes required:
- Modules generated by bindgen are marked
`#[allow(clippy::ptr_as_ptr)]`.
- Inferred casts (` as _`) are replaced with `.cast()`.
- Ascribed casts (` as *... T`) are replaced with `.cast::<T>()`.
- Multistep casts from references (` as *const _ as *const T`) are
replaced with `core::ptr::from_ref(&x).cast()` with or without `::<T>`
according to the previous rules. The `core::ptr::from_ref` call is
required because `(x as *const _).cast::<T>()` results in inference
failure.
- Native literal C strings are replaced with `c_str!().as_char_ptr()`.
- `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut
T)`.cast();` since pointer to pointer can be confusing.
Apply these changes and enable the lint -- no functional change
intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-1-f43b024581e8@gmail.com
[ Added `.cast()` for `opp`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
- Add support for the EXPORT_SYMBOL_GPL_FOR_MODULES() macro, which exports a
symbol only to specified modules
- Improve ABI handling in gendwarfksyms
- Forcibly link lib-y objects to vmlinux even if CONFIG_MODULES=n
- Add checkers for redundant or missing <linux/export.h> inclusion
- Deprecate the extra-y syntax
- Fix a genksyms bug when including enum constants from *.symref files
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Merge tag 'kbuild-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Add support for the EXPORT_SYMBOL_GPL_FOR_MODULES() macro, which
exports a symbol only to specified modules
- Improve ABI handling in gendwarfksyms
- Forcibly link lib-y objects to vmlinux even if CONFIG_MODULES=n
- Add checkers for redundant or missing <linux/export.h> inclusion
- Deprecate the extra-y syntax
- Fix a genksyms bug when including enum constants from *.symref files
* tag 'kbuild-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
genksyms: Fix enum consts from a reference affecting new values
arch: use always-$(KBUILD_BUILTIN) for vmlinux.lds
kbuild: set y instead of 1 to KBUILD_{BUILTIN,MODULES}
efi/libstub: use 'targets' instead of extra-y in Makefile
module: make __mod_device_table__* symbols static
scripts/misc-check: check unnecessary #include <linux/export.h> when W=1
scripts/misc-check: check missing #include <linux/export.h> when W=1
scripts/misc-check: add double-quotes to satisfy shellcheck
kbuild: move W=1 check for scripts/misc-check to top-level Makefile
scripts/tags.sh: allow to use alternative ctags implementation
kconfig: introduce menu type enum
docs: symbol-namespaces: fix reST warning with literal block
kbuild: link lib-y objects to vmlinux forcibly even when CONFIG_MODULES=n
tinyconfig: enable CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
docs/core-api/symbol-namespaces: drop table of contents and section numbering
modpost: check forbidden MODULE_IMPORT_NS("module:") at compile time
kbuild: move kbuild syntax processing to scripts/Makefile.build
Makefile: remove dependency on archscripts for header installation
Documentation/kbuild: Add new gendwarfksyms kABI rules
Documentation/kbuild: Drop section numbers
...
KBUILD_BUILTIN is set to 1 unless you are building only modules.
KBUILD_MODULES is set to 1 when you are building only modules
(a typical use case is "make modules").
It is more useful to set them to 'y' instead, so we can do
something like:
always-$(KBUILD_BUILTIN) += vmlinux.lds
This works equivalently to:
extra-y += vmlinux.lds
This allows us to deprecate extra-y. extra-y and always-y are quite
similar, and we do not need both.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
This script is executed only when ${KBUILD_EXTRA_WARN} contains 1.
Move this check to the top-level Makefile to allow more checks to be
easily added to this script.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Since commit 7273ad2b08 ("kbuild: link lib-y objects to vmlinux
forcibly when CONFIG_MODULES=y"), all objects from lib-y have been
forcibly linked to vmlinux when CONFIG_MODULES=y.
To simplify future changes, this commit makes all objects from lib-y
be linked regardless of the CONFIG_MODULES setting.
Most use cases (CONFIG_MODULES=y) are not affected by this change.
The vmlinux size with ARCH=arm allnoconfig, where CONFIG_MODULES=n,
increases as follows:
text data bss dec hex filename
1368644 835104 206288 2410036 24c634 vmlinux.before
1379440 837064 206288 2422792 24f808 vmlinux.after
We no longer benefit from using static libraries, but the impact is
mitigated by supporting CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
For example, the size of vmlinux remains almost the same with ARCH=arm
tinyconfig, where CONFIG_MODULES=n and
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y.
text data bss dec hex filename
455316 93404 15472 564192 89be0 vmlinux.before
455312 93404 15472 564188 89bdc vmlinux.after
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
- The most significant change is the replacement of the old kernel-doc
script (a monstrous collection of Perl regexes that predates the Git era)
with a Python reimplementation. That, too, is a horrifying collection of
regexes, but in a much cleaner and more maintainable structure that
integrates far better with the Sphinx build system.
This change has been in linux-next for the full 6.15 cycle; the small
number of problems that turned up have been addressed, seemingly to
everybody's satisfaction. The Perl kernel-doc script remains in tree (as
scripts/kernel-doc.pl) and can be used with a command-line option if need
be. Unless some reason to keep it around materializes, it will probably
go away in 6.17.
Credit goes to Mauro Carvalho Chehab for doing all this work.
- Some RTLA documentation updates
- A handful of Chinese translations
- The usual collection of typo fixes, general updates, etc.
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Merge tag 'docs-6.16' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"A moderately busy cycle for documentation this time around:
- The most significant change is the replacement of the old
kernel-doc script (a monstrous collection of Perl regexes that
predates the Git era) with a Python reimplementation. That, too, is
a horrifying collection of regexes, but in a much cleaner and more
maintainable structure that integrates far better with the Sphinx
build system.
This change has been in linux-next for the full 6.15 cycle; the
small number of problems that turned up have been addressed,
seemingly to everybody's satisfaction. The Perl kernel-doc script
remains in tree (as scripts/kernel-doc.pl) and can be used with a
command-line option if need be. Unless some reason to keep it
around materializes, it will probably go away in 6.17.
Credit goes to Mauro Carvalho Chehab for doing all this work.
- Some RTLA documentation updates
- A handful of Chinese translations
- The usual collection of typo fixes, general updates, etc"
* tag 'docs-6.16' of git://git.lwn.net/linux: (85 commits)
Docs: doc-guide: update sphinx.rst Sphinx version number
docs: doc-guide: clarify latest theme usage
Documentation/scheduler: Fix typo in sched-stats domain field description
scripts: kernel-doc: prevent a KeyError when checking output
docs: kerneldoc.py: simplify exception handling logic
MAINTAINERS: update linux-doc entry to cover new Python scripts
docs: align with scripts/syscall.tbl migration
Documentation: NTB: Fix typo
Documentation: ioctl-number: Update table intro
docs: conf.py: drop backward support for old Sphinx versions
Docs: driver-api/basics: add kobject_event interfaces
Docs: relay: editing cleanups
docs: fix "incase" typo in coresight/panic.rst
Fix spelling error for 'parallel'
docs: admin-guide: fix typos in reporting-issues.rst
docs: dmaengine: add explanation for DMA_ASYNC_TX capability
Documentation: leds: improve readibility of multicolor doc
docs: fix typo in firmware-related section
docs: Makefile: Inherit PYTHONPYCACHEPREFIX setting as env variable
Documentation: ioctl-number: Update outdated submission info
...
archscripts has nothing to do with headers_install.
Signed-off-by: Henrik Lindström <henrik@lxm.se>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This reverts commit dbdffaf50f.
--remap-path-prefix breaks the ability of debuggers to find the source
file corresponding to object files. As there is no simple or uniform
way to specify the source directory explicitly, this breaks developers
workflows.
Revert the unconditional usage of --remap-path-prefix, equivalent to the
same change for -ffile-prefix-map in KBUILD_CPPFLAGS.
Fixes: dbdffaf50f ("kbuild, rust: use -fremap-path-prefix to make paths relative")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This reverts commit cacd22ce69.
-ffile-prefix-map breaks the ability of debuggers to find the source
file corresponding to object files. As there is no simple or uniform
way to specify the source directory explicitly, this breaks developers
workflows.
Revert the unconditional usage of -ffile-prefix-map.
Reported-by: Matthieu Baerts <matttbe@kernel.org>
Closes: https://lore.kernel.org/lkml/edc50aa7-0740-4942-8c15-96f12f2acc7e@kernel.org/
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Closes: https://lore.kernel.org/lkml/aBEttQH4kimHFScx@intel.com/
Fixes: cacd22ce69 ("kbuild: make all file references relative to source root")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Clang and GCC have different behaviors around disabling warnings
included in -Wall and -Wextra and the order in which flags are
specified, which is exposed by clang's new support for
-Wunterminated-string-initialization.
$ cat test.c
const char foo[3] = "FOO";
const char bar[3] __attribute__((__nonstring__)) = "BAR";
$ clang -fsyntax-only -Wextra test.c
test.c:1:21: warning: initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute? [-Wunterminated-string-initialization]
1 | const char foo[3] = "FOO";
| ^~~~~
$ clang -fsyntax-only -Wextra -Wno-unterminated-string-initialization test.c
$ clang -fsyntax-only -Wno-unterminated-string-initialization -Wextra test.c
test.c:1:21: warning: initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute? [-Wunterminated-string-initialization]
1 | const char foo[3] = "FOO";
| ^~~~~
$ gcc -fsyntax-only -Wextra test.c
test.c:1:21: warning: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (4 chars into 3 available) [-Wunterminated-string-initialization]
1 | const char foo[3] = "FOO";
| ^~~~~
$ gcc -fsyntax-only -Wextra -Wno-unterminated-string-initialization test.c
$ gcc -fsyntax-only -Wno-unterminated-string-initialization -Wextra test.c
Move -Wextra up right below -Wall in Makefile.extrawarn to ensure these
flags are at the beginning of the warning options list. Move the couple
of warning options that have been added to the main Makefile since
commit e88ca24319 ("kbuild: consolidate warning flags in
scripts/Makefile.extrawarn") to scripts/Makefile.extrawarn after -Wall /
-Wextra to ensure they get properly disabled for all compilers.
Fixes: 9d7a0577c9 ("gcc-15: disable '-Wunterminated-string-initialization' entirely for now")
Link: https://github.com/llvm/llvm-project/issues/10359
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As kernel-doc script is used not only on Documentation, but
also on scripts and drivers/drm Makefiles, move it to the
main makefile, as otherwise sub-makefiles may not have it.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <bb3ea3b49e76aee51dae7762db10c4d38cd67afe.1745453655.git.mchehab+huawei@kernel.org>
This was triggered by one of my mis-uses causing odd build warnings on
sparc in linux-next, but while figuring out why the "obviously correct"
use of cc-option caused such odd breakage, I found eight other cases of
the same thing in the tree.
The root cause is that 'cc-option' doesn't work for checking negative
warning options (ie things like '-Wno-stringop-overflow') because gcc
will silently accept options it doesn't recognize, and so 'cc-option'
ends up thinking they are perfectly fine.
And it all works, until you have a situation where _another_ warning is
emitted. At that point the compiler will go "Hmm, maybe the user
intended to disable this warning but used that wrong option that I
didn't recognize", and generate a warning for the unrecognized negative
option.
Which explains why we have several cases of this in the tree: the
'cc-option' test really doesn't work for this situation, but most of the
time it simply doesn't matter that ity doesn't work.
The reason my recently added case caused problems on sparc was pointed
out by Thomas Weißschuh: the sparc build had a previous explicit warning
that then triggered the new one.
I think the best fix for this would be to make 'cc-option' a bit smarter
about this sitation, possibly by adding an intentional warning to the
test case that then triggers the unrecognized option warning reliably.
But the short-term fix is to replace 'cc-option' with an existing helper
designed for this exact case: 'cc-disable-warning', which picks the
negative warning but uses the positive form for testing the compiler
support.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/all/20250422204718.0b4e3f81@canb.auug.org.au/
Explained-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I had left the warning around but as a non-fatal error to get my gcc-15
builds going, but fixed up some of the most annoying warning cases so
that it wouldn't be *too* verbose.
Because I like the _concept_ of the warning, even if I detested the
implementation to shut it up.
It turns out the implementation to shut it up is even more broken than I
thought, and my "shut up most of the warnings" patch just caused fatal
errors on gcc-14 instead.
I had tested with clang, but when I upgrade my development environment,
I try to do it on all machines because I hate having different systems
to maintain, and hadn't realized that gcc-14 now had issues.
The ACPI case is literally why I wanted to have a *type* that doesn't
trigger the warning (see commit d5d45a7f2619: "gcc-15: make
'unterminated string initialization' just a warning"), instead of
marking individual places as "__nonstring".
But gcc-14 doesn't like that __nonstring location that shut gcc-15 up,
because it's on an array of char arrays, not on one single array:
drivers/acpi/tables.c:399:1: error: 'nonstring' attribute ignored on objects of type 'const char[][4]' [-Werror=attributes]
399 | static const char table_sigs[][ACPI_NAMESEG_SIZE] __initconst __nonstring = {
| ^~~~~~
and my attempts to nest it properly with a type had failed, because of
how gcc doesn't like marking the types as having attributes, only
symbols.
There may be some trick to it, but I was already annoyed by the bad
attribute design, now I'm just entirely fed up with it.
I wish gcc had a proper way to say "this type is a *byte* array, not a
string".
The obvious thing would be to distinguish between "char []" and an
explicitly signed "unsigned char []" (as opposed to an implicitly
unsigned char, which is typically an architecture-specific default, but
for the kernel is universal thanks to '-funsigned-char').
But any "we can typedef a 8-bit type to not become a string just because
it's an array" model would be fine.
But "__attribute__((nonstring))" is sadly not that sane model.
Reported-by: Chris Clayton <chris2553@googlemail.com>
Fixes: 4b4bd8c50f ("gcc-15: acpi: sprinkle random '__nonstring' crumbles around")
Fixes: d5d45a7f26 ("gcc-15: make 'unterminated string initialization' just a warning")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc-15 enabling -Wunterminated-string-initialization in -Wextra by
default was done with the best intentions, but the warning is still
quite broken.
What annoys me about the warning is that this is a very traditional AND
CORRECT way to initialize fixed byte arrays in C:
unsigned char hex[16] = "0123456789abcdef";
and we use this all over the kernel. And the warning is fine, but gcc
developers apparently never made a reasonable way to disable it. As is
(sadly) tradition with these things.
Yes, there's "__attribute__((nonstring))", and we have a macro to make
that absolutely disgusting syntax more palatable (ie the kernel syntax
for that monstrosity is just "__nonstring").
But that attribute is misdesigned. What you'd typically want to do is
tell the compiler that you are using a type that isn't a string but a
byte array, but that doesn't work at all:
warning: ‘nonstring’ attribute does not apply to types [-Wattributes]
and because of this fundamental mis-design, you then have to mark each
instance of that pattern.
This is particularly noticeable in our ACPI code, because ACPI has this
notion of a 4-byte "type name" that gets used all over, and is exactly
this kind of byte array.
This is a sad oversight, because the warning is useful, but really would
be so much better if gcc had also given a sane way to indicate that we
really just want a byte array type at a type level, not the broken "each
and every array definition" level.
So now instead of creating a nice "ACPI name" type using something like
typedef char acpi_name_t[4] __nonstring;
we have to do things like
char name[ACPI_NAMESEG_SIZE] __nonstring;
in every place that uses this concept and then happens to have the
typical initializers.
This is annoying me mainly because I think the warning _is_ a good
warning, which is why I'm not just turning it off in disgust. But it is
hampered by this bad implementation detail.
[ And obviously I'm doing this now because system upgrades for me are
something that happen in the middle of the release cycle: don't do it
before or during travel, or just before or during the busy merge
window period. ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Toolchain and infrastructure:
- Fix missing KASAN LLVM flags on first build (and fix spurious
rebuilds) by skipping '--target'.
- Fix Make < 4.3 build error by using '$(pound)'.
- Fix UML build error by removing 'volatile' qualifier from io helpers.
- Fix UML build error by adding 'dma_{alloc,free}_attrs()' helpers.
- Clean gendwarfksyms warnings by avoiding to export '__pfx' symbols.
- Clean objtool warning by adding a new 'noreturn' function for 1.86.0.
- Disable 'needless_continue' Clippy lint due to new 1.86.0 warnings.
- Add missing 'ffi' crate to 'generate_rust_analyzer.py'.
'pin-init' crate:
- Import a couple fixes from upstream.
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Merge tag 'rust-fixes-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix missing KASAN LLVM flags on first build (and fix spurious
rebuilds) by skipping '--target'
- Fix Make < 4.3 build error by using '$(pound)'
- Fix UML build error by removing 'volatile' qualifier from io
helpers
- Fix UML build error by adding 'dma_{alloc,free}_attrs()' helpers
- Clean gendwarfksyms warnings by avoiding to export '__pfx' symbols
- Clean objtool warning by adding a new 'noreturn' function for
1.86.0
- Disable 'needless_continue' Clippy lint due to new 1.86.0 warnings
- Add missing 'ffi' crate to 'generate_rust_analyzer.py'
'pin-init' crate:
- Import a couple fixes from upstream"
* tag 'rust-fixes-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: helpers: Add dma_alloc_attrs() and dma_free_attrs()
rust: helpers: Remove volatile qualifier from io helpers
rust: kbuild: use `pound` to support GNU Make < 4.3
objtool/rust: add one more `noreturn` Rust function for Rust 1.86.0
rust: kasan/kbuild: fix missing flags on first build
rust: disable `clippy::needless_continue`
rust: kbuild: Don't export __pfx symbols
rust: pin-init: use Markdown autolinks in Rust comments
rust: pin-init: alloc: restrict `impl ZeroableOption` for `Box` to `T: Sized`
scripts: generate_rust_analyzer: Add ffi crate
Starting with Rust 1.86.0, Clippy's `needless_continue` lint complains
about the last statement of a loop [1], including cases like:
while ... {
match ... {
... if ... => {
...
return ...;
}
_ => continue,
}
}
as well as nested `match`es in a loop.
One solution is changing `continue` for `()` [2], but arguably using
`continue` shows the intent better when it is alone in an arm like that.
Moreover, I am not sure we want to force people to try to find other
ways to write the code either, in cases when that applies.
In addition, the help text does not really apply in the new cases the
lint has introduced, e.g. here one cannot simply "drop" the expression:
warning: this `continue` expression is redundant
--> rust/macros/helpers.rs:85:18
|
85 | _ => continue,
| ^^^^^^^^
|
= help: consider dropping the `continue` expression
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue
= note: requested on the command line with `-W clippy::needless-continue`
The examples in the documentation do not show a case like this, either,
so the second "help" line does not help.
In addition, locally disabling the lint is not possible with `expect`,
since the behavior differs across versions. Using `allow` would be
possible, but, even then, an extra line just for this is a bit too much,
especially if there are other ways to satisfy the lint.
Finally, the lint is still in the "pedantic" category and disabled by
default by Clippy.
Thus disable the lint, at least for the time being.
Feedback was submitted to upstream Clippy, in case this can be improved
or perhaps the lint split into several [3].
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust-clippy/pull/13891 [1]
Link: https://lore.kernel.org/rust-for-linux/20250401221205.52381-1-ojeda@kernel.org/ [2]
Link: https://github.com/rust-lang/rust-clippy/issues/14536 [3]
Link: https://lore.kernel.org/r/20250403163805.67770-1-ojeda@kernel.org
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
A recent optimization change in LLVM [1] aims to transform certain loop
idioms into calls to strlen() or wcslen(). This change transforms the
first while loop in UniStrcat() into a call to wcslen(), breaking the
build when UniStrcat() gets inlined into alloc_path_with_tree_prefix():
ld.lld: error: undefined symbol: wcslen
>>> referenced by nls_ucs2_utils.h:54 (fs/smb/client/../../nls/nls_ucs2_utils.h:54)
>>> vmlinux.o:(alloc_path_with_tree_prefix)
>>> referenced by nls_ucs2_utils.h:54 (fs/smb/client/../../nls/nls_ucs2_utils.h:54)
>>> vmlinux.o:(alloc_path_with_tree_prefix)
Disable this optimization with '-fno-builtin-wcslen', which prevents the
compiler from assuming that wcslen() is available in the kernel's C
library.
[ More to the point - it's not that we couldn't implement wcslen(), it's
that this isn't an optimization at all in the context of the kernel.
Replacing a simple inlined loop with a function call to the same loop
is just stupid and pointless if you don't have long strings and fancy
libraries with vectorization support etc.
For the regular 'strlen()' cases, we want the compiler to do this in
order to handle the trivial case of constant strings. And we do have
optimized versions of 'strlen()' on some architectures. But for
wcslen? Just no. - Linus ]
Cc: stable@vger.kernel.org
Link: 9694844d7e [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Improve performance in gendwarfksyms
- Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS
- Support CONFIG_HEADERS_INSTALL for ARCH=um
- Use more relative paths to sources files for better reproducibility
- Support the loong64 Debian architecture
- Add Kbuild bash completion
- Introduce intermediate vmlinux.unstripped for architectures that need
static relocations to be stripped from the final vmlinux
- Fix versioning in Debian packages for -rc releases
- Treat missing MODULE_DESCRIPTION() as an error
- Convert Nios2 Makefiles to use the generic rule for built-in DTB
- Add debuginfo support to the RPM package
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Merge tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Improve performance in gendwarfksyms
- Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS
- Support CONFIG_HEADERS_INSTALL for ARCH=um
- Use more relative paths to sources files for better reproducibility
- Support the loong64 Debian architecture
- Add Kbuild bash completion
- Introduce intermediate vmlinux.unstripped for architectures that need
static relocations to be stripped from the final vmlinux
- Fix versioning in Debian packages for -rc releases
- Treat missing MODULE_DESCRIPTION() as an error
- Convert Nios2 Makefiles to use the generic rule for built-in DTB
- Add debuginfo support to the RPM package
* tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits)
kbuild: rpm-pkg: build a debuginfo RPM
kconfig: merge_config: use an empty file as initfile
nios2: migrate to the generic rule for built-in DTB
rust: kbuild: skip `--remap-path-prefix` for `rustdoc`
kbuild: pacman-pkg: hardcode module installation path
kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally
modpost: require a MODULE_DESCRIPTION()
kbuild: make all file references relative to source root
x86: drop unnecessary prefix map configuration
kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS
kbuild: Add a help message for "headers"
kbuild: deb-pkg: remove "version" variable in mkdebian
kbuild: deb-pkg: fix versioning for -rc releases
Documentation/kbuild: Fix indentation in modules.rst example
x86: Get rid of Makefile.postlink
kbuild: Create intermediate vmlinux build with relocations preserved
kbuild: Introduce Kconfig symbol for linking vmlinux with relocations
kbuild: link-vmlinux.sh: Make output file name configurable
kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y
Revert "kheaders: Ignore silly-rename files"
...
two locking commits in the locking tree,
part of the locking-core-2025-03-22 pull request. ]
x86 CPU features support:
- Generate the <asm/cpufeaturemasks.h> header based on build config
(H. Peter Anvin, Xin Li)
- x86 CPUID parsing updates and fixes (Ahmed S. Darwish)
- Introduce the 'setcpuid=' boot parameter (Brendan Jackman)
- Enable modifying CPU bug flags with '{clear,set}puid='
(Brendan Jackman)
- Utilize CPU-type for CPU matching (Pawan Gupta)
- Warn about unmet CPU feature dependencies (Sohil Mehta)
- Prepare for new Intel Family numbers (Sohil Mehta)
Percpu code:
- Standardize & reorganize the x86 percpu layout and
related cleanups (Brian Gerst)
- Convert the stackprotector canary to a regular percpu
variable (Brian Gerst)
- Add a percpu subsection for cache hot data (Brian Gerst)
- Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak)
- Construct __percpu_seg_override from __percpu_seg (Uros Bizjak)
MM:
- Add support for broadcast TLB invalidation using AMD's INVLPGB instruction
(Rik van Riel)
- Rework ROX cache to avoid writable copy (Mike Rapoport)
- PAT: restore large ROX pages after fragmentation
(Kirill A. Shutemov, Mike Rapoport)
- Make memremap(MEMREMAP_WB) map memory as encrypted by default
(Kirill A. Shutemov)
- Robustify page table initialization (Kirill A. Shutemov)
- Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn)
- Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW
(Matthew Wilcox)
KASLR:
- x86/kaslr: Reduce KASLR entropy on most x86 systems,
to support PCI BAR space beyond the 10TiB region
(CONFIG_PCI_P2PDMA=y) (Balbir Singh)
CPU bugs:
- Implement FineIBT-BHI mitigation (Peter Zijlstra)
- speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta)
- speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan Gupta)
- RFDS: Exclude P-only parts from the RFDS affected list (Pawan Gupta)
System calls:
- Break up entry/common.c (Brian Gerst)
- Move sysctls into arch/x86 (Joel Granados)
Intel LAM support updates: (Maciej Wieczor-Retman)
- selftests/lam: Move cpu_has_la57() to use cpuinfo flag
- selftests/lam: Skip test if LAM is disabled
- selftests/lam: Test get_user() LAM pointer handling
AMD SMN access updates:
- Add SMN offsets to exclusive region access (Mario Limonciello)
- Add support for debugfs access to SMN registers (Mario Limonciello)
- Have HSMP use SMN through AMD_NODE (Yazen Ghannam)
Power management updates: (Patryk Wlazlyn)
- Allow calling mwait_play_dead with an arbitrary hint
- ACPI/processor_idle: Add FFH state handling
- intel_idle: Provide the default enter_dead() handler
- Eliminate mwait_play_dead_cpuid_hint()
Bootup:
Build system:
- Raise the minimum GCC version to 8.1 (Brian Gerst)
- Raise the minimum LLVM version to 15.0.0
(Nathan Chancellor)
Kconfig: (Arnd Bergmann)
- Add cmpxchg8b support back to Geode CPUs
- Drop 32-bit "bigsmp" machine support
- Rework CONFIG_GENERIC_CPU compiler flags
- Drop configuration options for early 64-bit CPUs
- Remove CONFIG_HIGHMEM64G support
- Drop CONFIG_SWIOTLB for PAE
- Drop support for CONFIG_HIGHPTE
- Document CONFIG_X86_INTEL_MID as 64-bit-only
- Remove old STA2x11 support
- Only allow CONFIG_EISA for 32-bit
Headers:
- Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI headers
(Thomas Huth)
Assembly code & machine code patching:
- x86/alternatives: Simplify alternative_call() interface (Josh Poimboeuf)
- x86/alternatives: Simplify callthunk patching (Peter Zijlstra)
- KVM: VMX: Use named operands in inline asm (Josh Poimboeuf)
- x86/hyperv: Use named operands in inline asm (Josh Poimboeuf)
- x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra)
- x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h>
(Uros Bizjak)
- Use named operands in inline asm (Uros Bizjak)
- Improve performance by using asm_inline() for atomic locking instructions
(Uros Bizjak)
Earlyprintk:
- Harden early_serial (Peter Zijlstra)
NMI handler:
- Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus()
(Waiman Long)
Miscellaneous fixes and cleanups:
- by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel,
Artem Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst,
Dan Carpenter, Dr. David Alan Gilbert, H. Peter Anvin,
Ingo Molnar, Josh Poimboeuf, Kevin Brodsky, Mike Rapoport,
Lukas Bulwahn, Maciej Wieczor-Retman, Max Grobecker,
Patryk Wlazlyn, Pawan Gupta, Peter Zijlstra,
Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner,
Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak,
Vitaly Kuznetsov, Xin Li, liuye.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core x86 updates from Ingo Molnar:
"x86 CPU features support:
- Generate the <asm/cpufeaturemasks.h> header based on build config
(H. Peter Anvin, Xin Li)
- x86 CPUID parsing updates and fixes (Ahmed S. Darwish)
- Introduce the 'setcpuid=' boot parameter (Brendan Jackman)
- Enable modifying CPU bug flags with '{clear,set}puid=' (Brendan
Jackman)
- Utilize CPU-type for CPU matching (Pawan Gupta)
- Warn about unmet CPU feature dependencies (Sohil Mehta)
- Prepare for new Intel Family numbers (Sohil Mehta)
Percpu code:
- Standardize & reorganize the x86 percpu layout and related cleanups
(Brian Gerst)
- Convert the stackprotector canary to a regular percpu variable
(Brian Gerst)
- Add a percpu subsection for cache hot data (Brian Gerst)
- Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak)
- Construct __percpu_seg_override from __percpu_seg (Uros Bizjak)
MM:
- Add support for broadcast TLB invalidation using AMD's INVLPGB
instruction (Rik van Riel)
- Rework ROX cache to avoid writable copy (Mike Rapoport)
- PAT: restore large ROX pages after fragmentation (Kirill A.
Shutemov, Mike Rapoport)
- Make memremap(MEMREMAP_WB) map memory as encrypted by default
(Kirill A. Shutemov)
- Robustify page table initialization (Kirill A. Shutemov)
- Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn)
- Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW
(Matthew Wilcox)
KASLR:
- x86/kaslr: Reduce KASLR entropy on most x86 systems, to support PCI
BAR space beyond the 10TiB region (CONFIG_PCI_P2PDMA=y) (Balbir
Singh)
CPU bugs:
- Implement FineIBT-BHI mitigation (Peter Zijlstra)
- speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta)
- speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan
Gupta)
- RFDS: Exclude P-only parts from the RFDS affected list (Pawan
Gupta)
System calls:
- Break up entry/common.c (Brian Gerst)
- Move sysctls into arch/x86 (Joel Granados)
Intel LAM support updates: (Maciej Wieczor-Retman)
- selftests/lam: Move cpu_has_la57() to use cpuinfo flag
- selftests/lam: Skip test if LAM is disabled
- selftests/lam: Test get_user() LAM pointer handling
AMD SMN access updates:
- Add SMN offsets to exclusive region access (Mario Limonciello)
- Add support for debugfs access to SMN registers (Mario Limonciello)
- Have HSMP use SMN through AMD_NODE (Yazen Ghannam)
Power management updates: (Patryk Wlazlyn)
- Allow calling mwait_play_dead with an arbitrary hint
- ACPI/processor_idle: Add FFH state handling
- intel_idle: Provide the default enter_dead() handler
- Eliminate mwait_play_dead_cpuid_hint()
Build system:
- Raise the minimum GCC version to 8.1 (Brian Gerst)
- Raise the minimum LLVM version to 15.0.0 (Nathan Chancellor)
Kconfig: (Arnd Bergmann)
- Add cmpxchg8b support back to Geode CPUs
- Drop 32-bit "bigsmp" machine support
- Rework CONFIG_GENERIC_CPU compiler flags
- Drop configuration options for early 64-bit CPUs
- Remove CONFIG_HIGHMEM64G support
- Drop CONFIG_SWIOTLB for PAE
- Drop support for CONFIG_HIGHPTE
- Document CONFIG_X86_INTEL_MID as 64-bit-only
- Remove old STA2x11 support
- Only allow CONFIG_EISA for 32-bit
Headers:
- Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI
headers (Thomas Huth)
Assembly code & machine code patching:
- x86/alternatives: Simplify alternative_call() interface (Josh
Poimboeuf)
- x86/alternatives: Simplify callthunk patching (Peter Zijlstra)
- KVM: VMX: Use named operands in inline asm (Josh Poimboeuf)
- x86/hyperv: Use named operands in inline asm (Josh Poimboeuf)
- x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra)
- x86/kexec: Merge x86_32 and x86_64 code using macros from
<asm/asm.h> (Uros Bizjak)
- Use named operands in inline asm (Uros Bizjak)
- Improve performance by using asm_inline() for atomic locking
instructions (Uros Bizjak)
Earlyprintk:
- Harden early_serial (Peter Zijlstra)
NMI handler:
- Add an emergency handler in nmi_desc & use it in
nmi_shootdown_cpus() (Waiman Long)
Miscellaneous fixes and cleanups:
- by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel, Artem
Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst, Dan
Carpenter, Dr. David Alan Gilbert, H. Peter Anvin, Ingo Molnar,
Josh Poimboeuf, Kevin Brodsky, Mike Rapoport, Lukas Bulwahn, Maciej
Wieczor-Retman, Max Grobecker, Patryk Wlazlyn, Pawan Gupta, Peter
Zijlstra, Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner,
Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak, Vitaly
Kuznetsov, Xin Li, liuye"
* tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (211 commits)
zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault
x86/asm: Make asm export of __ref_stack_chk_guard unconditional
x86/mm: Only do broadcast flush from reclaim if pages were unmapped
perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM ones
perf/x86/intel, x86/cpu: Simplify Intel PMU initialization
x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers
x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers
x86/locking/atomic: Improve performance by using asm_inline() for atomic locking instructions
x86/asm: Use asm_inline() instead of asm() in clwb()
x86/asm: Use CLFLUSHOPT and CLWB mnemonics in <asm/special_insns.h>
x86/hweight: Use asm_inline() instead of asm()
x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm()
x86/hweight: Use named operands in inline asm()
x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMP
x86/head/64: Avoid Clang < 17 stack protector in startup code
x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h>
x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro
x86/cpu/intel: Limit the non-architectural constant_tsc model checks
x86/mm/pat: Replace Intel x86_model checks with VFM ones
x86/cpu/intel: Fix fast string initialization for extended Families
...
-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>
Meanwhile explicitly state that the headers are uapi headers.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The imperative paradigm used to build vmlinux, extract some info from it
or perform some checks on it, and subsequently modify it again goes
against the declarative paradigm that is usually employed for defining
make rules.
In particular, the Makefile.postlink files that consume their input via
an output rule result in some dodgy logic in the decompressor makefiles
for RISC-V and x86, given that the vmlinux.relocs input file needed to
generate the arch-specific relocation tables may not exist or be out of
date, but cannot be constructed using the ordinary Make dependency based
rules, because the info needs to be extracted while vmlinux is in its
ephemeral, non-stripped form.
So instead, for architectures that require the static relocations that
are emitted into vmlinux when passing --emit-relocs to the linker, and
are subsequently stripped out again, introduce an intermediate vmlinux
target called vmlinux.unstripped, and organize the reset of the build
logic accordingly:
- vmlinux.unstripped is created only once, and not updated again
- build rules under arch/*/boot can depend on vmlinux.unstripped without
running the risk of the data disappearing or being out of date
- the final vmlinux generated by the build is not bloated with static
relocations that are never needed again after the build completes.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Some architectures build vmlinux with static relocations preserved, but
strip them again from the final vmlinux image. Arch specific tools
consume these static relocations in order to construct relocation tables
for KASLR.
The fact that vmlinux is created, consumed and subsequently updated goes
against the typical, declarative paradigm used by Make, which is based
on rules and dependencies. So as a first step towards cleaning this up,
introduce a Kconfig symbol to declare that the arch wants to consume the
static relocations emitted into vmlinux. This will be wired up further
in subsequent patches.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Remap source path prefixes in all output, including compiler
diagnostics, debug information, macro expansions, etc.
This removes a few absolute paths from the binary and also makes it
possible to use core::panic::Location properly.
Equivalent to the same configuration done for C sources in
commit 1d3730f001 ("kbuild: support -fmacro-prefix-map for external
modules") and commit a73619a845 ("kbuild: use -fmacro-prefix-map to
make __FILE__ a relative path").
Link: https://doc.rust-lang.org/rustc/command-line-arguments.html#--remap-path-prefix-remap-source-names-in-output
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
userprogs sometimes need access to UAPI headers.
This is currently not possible for Usermode Linux, as UM is only
a pseudo architecture built on top of a regular architecture and does
not have its own UAPI.
Instead use the UAPI headers from the underlying regular architecture.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Commit e27128db62 ("kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to
KBUILD_EXTRA_WARN") renamed KBUILD_ENABLE_EXTRA_GCC_CHECKS in 2019.
The migration in downstream code should be complete.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
The -fzero-init-padding-bits=all option is not a warning flag, so
defining it in scripts/Makefile.extrawarn is inconsistent.
Move it to the top-level Makefile for consistency.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
The userprog infrastructure links objects files through $(CC).
Either explicitly by manually calling $(CC) on multiple object files or
implicitly by directly compiling a source file to an executable.
The documentation at Documentation/kbuild/llvm.rst indicates that ld.lld
would be used for linking if LLVM=1 is specified.
However clang instead will use either a globally installed cross linker
from $PATH called ${target}-ld or fall back to the system linker, which
probably does not support crosslinking.
For the normal kernel build this is not an issue because the linker is
always executed directly, without the compiler being involved.
Explicitly pass --ld-path to clang so $(LD) is respected.
As clang 13.0.1 is required to build the kernel, this option is available.
Fixes: 7f3a59db27 ("kbuild: add infrastructure to build userspace programs")
Cc: stable@vger.kernel.org # needs wrapping in $(cc-option) for < 6.9
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
While WAIT_FOR_ENDBR is specified to be a full speculation stop; it
has been shown that some implementations are 'leaky' to such an extend
that speculation can escape even the FineIBT preamble.
To deal with this, add additional hardening to the FineIBT preamble.
Notably, using a new LLVM feature:
e223485c9b
which encodes the number of arguments in the kCFI preamble's register.
Using this register<->arity mapping, have the FineIBT preamble CALL
into a stub clobbering the relevant argument registers in the
speculative case.
Scott sayeth thusly:
Microarchitectural attacks such as Branch History Injection (BHI) and
Intra-mode Branch Target Injection (IMBTI) [1] can cause an indirect
call to mispredict to an adversary-influenced target within the same
hardware domain (e.g., within the kernel). Instructions at the
mispredicted target may execute speculatively and potentially expose
kernel data (e.g., to a user-mode adversary) through a
microarchitectural covert channel such as CPU cache state.
CET-IBT [2] is a coarse-grained control-flow integrity (CFI) ISA
extension that enforces that each indirect call (or indirect jump)
must land on an ENDBR (end branch) instruction, even speculatively*.
FineIBT is a software technique that refines CET-IBT by associating
each function type with a 32-bit hash and enforcing (at the callee)
that the hash of the caller's function pointer type matches the hash
of the callee's function type. However, recent research [3] has
demonstrated that the conditional branch that enforces FineIBT's hash
check can be coerced to mispredict, potentially allowing an adversary
to speculatively bypass the hash check:
__cfi_foo:
ENDBR64
SUB R10d, 0x01234567
JZ foo # Even if the hash check fails and ZF=0, this branch could still mispredict as taken
UD2
foo:
...
The techniques demonstrated in [3] require the attacker to be able to
control the contents of at least one live register at the mispredicted
target. Therefore, this patch set introduces a sequence of CMOV
instructions at each indirect-callable target that poisons every live
register with data that the attacker cannot control whenever the
FineIBT hash check fails, thus mitigating any potential attack.
The security provided by this scheme has been discussed in detail on
an earlier thread [4].
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html
[2] Intel Software Developer's Manual, Volume 1, Chapter 18
[3] https://www.vusec.net/projects/native-bhi/
[4] https://lore.kernel.org/lkml/20240927194925.707462984@infradead.org/
*There are some caveats for certain processors, see [1] for more info
Suggested-by: Scott Constable <scott.d.constable@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250224124200.820402212@infradead.org
scripts/Makefile.clang was changed in the linked commit to move --target from
KBUILD_CFLAGS to KBUILD_CPPFLAGS, as that generally has a broader scope.
However that variable is not inspected by the userprogs logic,
breaking cross compilation on clang.
Use both variables to detect bitsize and target arguments for userprogs.
Fixes: feb843a469 ("kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When CONFIG_OBJTOOL=y or CONFIG_DEBUG_INFO_BTF=y, parallel builds
show awkward "mkdir -p ..." logs.
$ make -j16
[ snip ]
mkdir -p /home/masahiro/ref/linux/tools/objtool && make O=/home/masahiro/ref/linux subdir=tools/objtool --no-print-directory -C objtool
mkdir -p /home/masahiro/ref/linux/tools/bpf/resolve_btfids && make O=/home/masahiro/ref/linux subdir=tools/bpf/resolve_btfids --no-print-directory -C bpf/resolve_btfids
Defining MAKEFLAGS=<value> on the command line wipes out command line
switches from the resultant MAKEFLAGS definition, even though the command
line switches are active. [1]
MAKEFLAGS puts all single-letter options into the first word, and that
word will be empty if no single-letter options were given. [2]
However, this breaks if MAKEFLAGS=<value> is given on the command line.
The tools/ and tools/% targets set MAKEFLAGS=<value> on the command
line, which breaks the following code in tools/scripts/Makefile.include:
short-opts := $(firstword -$(MAKEFLAGS))
If MAKEFLAGS really needs modification, it should be done through the
environment variable, as follows:
MAKEFLAGS=<value> $(MAKE) ...
That said, I question whether modifying MAKEFLAGS is necessary here.
The only flag we might want to exclude is --no-print-directory, as the
tools build system changes the working directory. However, people might
find the "Entering/Leaving directory" logs annoying.
I simply removed the offending MAKEFLAGS=<value>.
[1]: https://savannah.gnu.org/bugs/?62469
[2]: https://www.gnu.org/software/make/manual/make.html#Testing-Flags
Fixes: ea01fa9f63 ("tools: Connect to the kernel build system")
Fixes: a50e433327 ("perf tools: Honor parallel jobs")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Daniel Xu <dxu@dxuuu.xyz>
Core
----
- More core refactoring to reduce the RTNL lock contention,
including preparatory work for the per-network namespace RTNL lock,
replacing RTNL lock with a per device-one to protect NAPI-related
net device data and moving synchronize_net() calls outside such
lock.
- Extend drop reasons usage, adding net scheduler, AF_UNIX, bridge and
more specific TCP coverage.
- Reduce network namespace tear-down time by removing per-subsystems
synchronize_net() in tipc and sched.
- Add flow label selector support for fib rules, allowing traffic
redirection based on such header field.
Netfilter
---------
- Do not remove netdev basechain when last device is gone, allowing
netdev basechains without devices.
- Revisit the flowtable teardown strategy, dealing better with fin,
reset and re-open events.
- Scale-up IP-vs connection dumping by avoiding linear search on
each restart.
Protocols
---------
- A significant XDP socket refactor, consolidating and optimizing
several helpers into the core
- Better scaling of ICMP rate-limiting, by removing false-sharing in
inet peers handling.
- Introduces netlink notifications for multicast IPv4 and IPv6
address changes.
- Add ipsec support for IP-TFS/AggFrag encapsulation, allowing
aggregation and fragmentation of the inner IP.
- Add sysctl to configure TIME-WAIT reuse delay for TCP sockets,
to avoid local port exhaustion issues when the average connection
lifetime is very short.
- Support updating keys (re-keying) for connections using kernel
TLS (for TLS 1.3 only).
- Support ipv4-mapped ipv6 address clients in smc-r v2.
- Add support for jumbo data packet transmission in RxRPC sockets,
gluing multiple data packets in a single UDP packet.
- Support RxRPC RACK-TLP to manage packet loss and retransmission in
conjunction with the congestion control algorithm.
Driver API
----------
- Introduce a unified and structured interface for reporting PHY
statistics, exposing consistent data across different H/W via
ethtool.
- Make timestamping selectable, allow the user to select the desired
hwtstamp provider (PHY or MAC) administratively.
- Add support for configuring a header-data-split threshold (HDS)
value via ethtool, to deal with partial or buggy H/W implementation.
- Consolidate DSA drivers Energy Efficiency Ethernet support.
- Add EEE management to phylink, making use of the phylib
implementation.
- Add phylib support for in-band capabilities negotiation.
- Simplify how phylib-enabled mac drivers expose the supported
interfaces.
Tests and tooling
-----------------
- Make the YNL tool package-friendly to make it easier to deploy it
separately from the kernel.
- Increase TCP selftest coverage importing several packetdrill
test-cases.
- Regenerate the ethtool uapi header from the YNL spec,
to ease maintenance and future development.
- Add YNL support for decoding the link types used in net
self-tests, allowing a single build to run both net and
drivers/net.
Drivers
-------
- Ethernet high-speed NICs:
- nVidia/Mellanox (mlx5):
- add cross E-Switch QoS support
- add SW Steering support for ConnectX-8
- implement support for HW-Managed Flow Steering, improving the
rule deletion/insertion rate
- support for multi-host LAG
- Intel (ixgbe, ice, igb):
- ice: add support for devlink health events
- ixgbe: add initial support for E610 chipset variant
- igb: add support for AF_XDP zero-copy
- Meta:
- add support for basic RSS config
- allow changing the number of channels
- add hardware monitoring support
- Broadcom (bnxt):
- implement TCP data split and HDS threshold ethtool support,
enabling Device Memory TCP.
- Marvell Octeon:
- implement egress ipsec offload support for the cn10k family
- Hisilicon (HIBMC):
- implement unicast MAC filtering
- Ethernet NICs embedded and virtual:
- Convert UDP tunnel drivers to NETDEV_PCPU_STAT_DSTATS, avoiding
contented atomic operations for drop counters
- Freescale:
- quicc: phylink conversion
- enetc: support Tx and Rx checksum offload and improve TSO
performances
- MediaTek:
- airoha: introduce support for ETS and HTB Qdisc offload
- Microchip:
- lan78XX USB: preparation work for phylink conversion
- Synopsys (stmmac):
- support DWMAC IP on NXP Automotive SoCs S32G2xx/S32G3xx/S32R45
- refactor EEE support to leverage the new driver API
- optimize DMA and cache access to increase raw RX performances
by 40%
- TI:
- icssg-prueth: add multicast filtering support for VLAN
interface
- netkit:
- add ability to configure head/tailroom
- VXLAN:
- accepts packets with user-defined reserved bit
- Ethernet switches:
- Microchip:
- lan969x: add RGMII support
- lan969x: improve TX and RX performance using the FDMA engine
- nVidia/Mellanox:
- move Tx header handling to PCI driver, to ease XDP support
- Ethernet PHYs:
- Texas Instruments DP83822:
- add support for GPIO2 clock output
- Realtek:
- 8169: add support for RTL8125D rev.b
- rtl822x: add hwmon support for the temperature sensor
- Microchip:
- add support for RDS PTP hardware
- consolidate periodic output signal generation
- CAN:
- several DT-bindings to DT schema conversions
- tcan4x5x:
- add HW standby support
- support nWKRQ voltage selection
- kvaser:
- allowing Bus Error Reporting runtime configuration
- WiFi:
- the on-going Multi-Link Operation (MLO) effort continues, affecting
both the stack and in drivers
- mac80211/cfg80211:
- Emergency Preparedness Communication Services (EPCS) station mode
support
- support for adding and removing station links for MLO
- add support for WiFi 7/EHT mesh over 320 MHz channels
- report Tx power info for each link
- RealTek (rtw88):
- enable USB Rx aggregation and USB 3 to improve performance
- LED support
- RealTek (rtw89):
- refactor power save to support Multi-Link Operations
- add support for RTL8922AE-VS variant
- MediaTek (mt76):
- single wiphy multiband support (preparation for MLO)
- p2p device support
- add TP-Link TXE50UH USB adapter support
- Qualcomm (ath10k):
- support for the QCA6698AQ IP core
- Qualcomm (ath12k):
- enable MLO for QCN9274
- Bluetooth:
- Allow sysfs to trigger hdev reset, to allow recovering devices
not responsive from user-space
- MediaTek: add support for MT7922, MT7925, MT7921e devices
- Realtek: add support for RTL8851BE devices
- Qualcomm: add support for WCN785x devices
- ISO: allow BIG re-sync
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Paolo Abeni:
"This is slightly smaller than usual, with the most interesting work
being still around RTNL scope reduction.
Core:
- More core refactoring to reduce the RTNL lock contention, including
preparatory work for the per-network namespace RTNL lock, replacing
RTNL lock with a per device-one to protect NAPI-related net device
data and moving synchronize_net() calls outside such lock.
- Extend drop reasons usage, adding net scheduler, AF_UNIX, bridge
and more specific TCP coverage.
- Reduce network namespace tear-down time by removing per-subsystems
synchronize_net() in tipc and sched.
- Add flow label selector support for fib rules, allowing traffic
redirection based on such header field.
Netfilter:
- Do not remove netdev basechain when last device is gone, allowing
netdev basechains without devices.
- Revisit the flowtable teardown strategy, dealing better with fin,
reset and re-open events.
- Scale-up IP-vs connection dumping by avoiding linear search on each
restart.
Protocols:
- A significant XDP socket refactor, consolidating and optimizing
several helpers into the core
- Better scaling of ICMP rate-limiting, by removing false-sharing in
inet peers handling.
- Introduces netlink notifications for multicast IPv4 and IPv6
address changes.
- Add ipsec support for IP-TFS/AggFrag encapsulation, allowing
aggregation and fragmentation of the inner IP.
- Add sysctl to configure TIME-WAIT reuse delay for TCP sockets, to
avoid local port exhaustion issues when the average connection
lifetime is very short.
- Support updating keys (re-keying) for connections using kernel TLS
(for TLS 1.3 only).
- Support ipv4-mapped ipv6 address clients in smc-r v2.
- Add support for jumbo data packet transmission in RxRPC sockets,
gluing multiple data packets in a single UDP packet.
- Support RxRPC RACK-TLP to manage packet loss and retransmission in
conjunction with the congestion control algorithm.
Driver API:
- Introduce a unified and structured interface for reporting PHY
statistics, exposing consistent data across different H/W via
ethtool.
- Make timestamping selectable, allow the user to select the desired
hwtstamp provider (PHY or MAC) administratively.
- Add support for configuring a header-data-split threshold (HDS)
value via ethtool, to deal with partial or buggy H/W
implementation.
- Consolidate DSA drivers Energy Efficiency Ethernet support.
- Add EEE management to phylink, making use of the phylib
implementation.
- Add phylib support for in-band capabilities negotiation.
- Simplify how phylib-enabled mac drivers expose the supported
interfaces.
Tests and tooling:
- Make the YNL tool package-friendly to make it easier to deploy it
separately from the kernel.
- Increase TCP selftest coverage importing several packetdrill
test-cases.
- Regenerate the ethtool uapi header from the YNL spec, to ease
maintenance and future development.
- Add YNL support for decoding the link types used in net self-tests,
allowing a single build to run both net and drivers/net.
Drivers:
- Ethernet high-speed NICs:
- nVidia/Mellanox (mlx5):
- add cross E-Switch QoS support
- add SW Steering support for ConnectX-8
- implement support for HW-Managed Flow Steering, improving the
rule deletion/insertion rate
- support for multi-host LAG
- Intel (ixgbe, ice, igb):
- ice: add support for devlink health events
- ixgbe: add initial support for E610 chipset variant
- igb: add support for AF_XDP zero-copy
- Meta:
- add support for basic RSS config
- allow changing the number of channels
- add hardware monitoring support
- Broadcom (bnxt):
- implement TCP data split and HDS threshold ethtool support,
enabling Device Memory TCP.
- Marvell Octeon:
- implement egress ipsec offload support for the cn10k family
- Hisilicon (HIBMC):
- implement unicast MAC filtering
- Ethernet NICs embedded and virtual:
- Convert UDP tunnel drivers to NETDEV_PCPU_STAT_DSTATS, avoiding
contented atomic operations for drop counters
- Freescale:
- quicc: phylink conversion
- enetc: support Tx and Rx checksum offload and improve TSO
performances
- MediaTek:
- airoha: introduce support for ETS and HTB Qdisc offload
- Microchip:
- lan78XX USB: preparation work for phylink conversion
- Synopsys (stmmac):
- support DWMAC IP on NXP Automotive SoCs S32G2xx/S32G3xx/S32R45
- refactor EEE support to leverage the new driver API
- optimize DMA and cache access to increase raw RX performances
by 40%
- TI:
- icssg-prueth: add multicast filtering support for VLAN
interface
- netkit:
- add ability to configure head/tailroom
- VXLAN:
- accepts packets with user-defined reserved bit
- Ethernet switches:
- Microchip:
- lan969x: add RGMII support
- lan969x: improve TX and RX performance using the FDMA engine
- nVidia/Mellanox:
- move Tx header handling to PCI driver, to ease XDP support
- Ethernet PHYs:
- Texas Instruments DP83822:
- add support for GPIO2 clock output
- Realtek:
- 8169: add support for RTL8125D rev.b
- rtl822x: add hwmon support for the temperature sensor
- Microchip:
- add support for RDS PTP hardware
- consolidate periodic output signal generation
- CAN:
- several DT-bindings to DT schema conversions
- tcan4x5x:
- add HW standby support
- support nWKRQ voltage selection
- kvaser:
- allowing Bus Error Reporting runtime configuration
- WiFi:
- the on-going Multi-Link Operation (MLO) effort continues,
affecting both the stack and in drivers
- mac80211/cfg80211:
- Emergency Preparedness Communication Services (EPCS) station
mode support
- support for adding and removing station links for MLO
- add support for WiFi 7/EHT mesh over 320 MHz channels
- report Tx power info for each link
- RealTek (rtw88):
- enable USB Rx aggregation and USB 3 to improve performance
- LED support
- RealTek (rtw89):
- refactor power save to support Multi-Link Operations
- add support for RTL8922AE-VS variant
- MediaTek (mt76):
- single wiphy multiband support (preparation for MLO)
- p2p device support
- add TP-Link TXE50UH USB adapter support
- Qualcomm (ath10k):
- support for the QCA6698AQ IP core
- Qualcomm (ath12k):
- enable MLO for QCN9274
- Bluetooth:
- Allow sysfs to trigger hdev reset, to allow recovering devices
not responsive from user-space
- MediaTek: add support for MT7922, MT7925, MT7921e devices
- Realtek: add support for RTL8851BE devices
- Qualcomm: add support for WCN785x devices
- ISO: allow BIG re-sync"
* tag 'net-next-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1386 commits)
net/rose: prevent integer overflows in rose_setsockopt()
net: phylink: fix regression when binding a PHY
net: ethernet: ti: am65-cpsw: streamline TX queue creation and cleanup
net: ethernet: ti: am65-cpsw: streamline RX queue creation and cleanup
net: ethernet: ti: am65-cpsw: ensure proper channel cleanup in error path
ipv6: Convert inet6_rtm_deladdr() to per-netns RTNL.
ipv6: Convert inet6_rtm_newaddr() to per-netns RTNL.
ipv6: Move lifetime validation to inet6_rtm_newaddr().
ipv6: Set cfg.ifa_flags before device lookup in inet6_rtm_newaddr().
ipv6: Pass dev to inet6_addr_add().
ipv6: Convert inet6_ioctl() to per-netns RTNL.
ipv6: Hold rtnl_net_lock() in addrconf_init() and addrconf_cleanup().
ipv6: Hold rtnl_net_lock() in addrconf_dad_work().
ipv6: Hold rtnl_net_lock() in addrconf_verify_work().
ipv6: Convert net.ipv6.conf.${DEV}.XXX sysctl to per-netns RTNL.
ipv6: Add __in6_dev_get_rtnl_net().
net: stmmac: Drop redundant skb_mark_for_recycle() for SKB frags
net: mii: Fix the Speed display when the network cable is not connected
sysctl net: Remove macro checks for CONFIG_SYSCTL
eth: bnxt: update header sizing defaults
...
Toolchain and infrastructure:
- Finish the move to custom FFI integer types started in the previous
cycle and finally map 'long' to 'isize' and 'char' to 'u8'. Do a few
cleanups on top thanks to that.
- Start to use 'derive(CoercePointee)' on Rust >= 1.84.0.
This is a major milestone on the path to build the kernel using only
stable Rust features. In particular, previously we were using the
unstable features 'coerce_unsized', 'dispatch_from_dyn' and 'unsize',
and now we will use the new 'derive_coerce_pointee' one, which is on
track to stabilization. This new feature is a macro that essentially
expands into code that internally uses the unstable features that we
were using before, without having to expose those.
With it, stable Rust users, including the kernel, will be able to
build custom smart pointers that work with trait objects, e.g.:
fn f(p: &Arc<dyn Display>) {
pr_info!("{p}\n");
}
let a: Arc<dyn Display> = Arc::new(42i32, GFP_KERNEL)?;
let b: Arc<dyn Display> = Arc::new("hello there", GFP_KERNEL)?;
f(&a); // Prints "42".
f(&b); // Prints "hello there".
Together with the 'arbitrary_self_types' feature that we started
using in the previous cycle, using our custom smart pointers like
'Arc' will eventually only rely in stable Rust.
- Introduce 'PROCMACROLDFLAGS' environment variable to allow to link
Rust proc macros using different flags than those used for linking
Rust host programs (e.g. when 'rustc' uses a different C library
than the host programs' one), which Android needs.
- Help kernel builds under macOS with Rust enabled by accomodating
other naming conventions for dynamic libraries (i.e. '.so' vs.
'.dylib') which are used for Rust procedural macros. The actual
support for macOS (i.e. the rest of the pieces needed) is provided
out-of-tree by others, following the policy used for other parts of
the kernel by Kbuild.
- Run Clippy for 'rusttest' code too and clean the bits it spotted.
- Provide Clippy with the minimum supported Rust version to improve
the suggestions it gives.
- Document 'bindgen' 0.71.0 regression.
'kernel' crate:
- 'build_error!': move users of the hidden function to the documented
macro, prevent such uses in the future by moving the function
elsewhere and add the macro to the prelude.
- 'types' module: add improved version of 'ForeignOwnable::borrow_mut'
(which was removed in the past since it was problematic); change
'ForeignOwnable' pointer type to '*mut'.
- 'alloc' module: implement 'Display' for 'Box' and align the 'Debug'
implementation to it; add example (doctest) for 'ArrayLayout::new()'.
- 'sync' module: document 'PhantomData' in 'Arc'; use
'NonNull::new_unchecked' in 'ForeignOwnable for Arc' impl.
- 'uaccess' module: accept 'Vec's with different allocators in
'UserSliceReader::read_all'.
- 'workqueue' module: enable run-testing a couple more doctests.
- 'error' module: simplify 'from_errno()'.
- 'block' module: fix formatting in code documentation (a lint to catch
these is being implemented).
- Avoid 'unwrap()'s in doctests, which also improves the examples by
showing how kernel code is supposed to be written.
- Avoid 'as' casts with 'cast{,_mut}' calls which are a bit safer.
And a few other cleanups.
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Merge tag 'rust-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Finish the move to custom FFI integer types started in the previous
cycle and finally map 'long' to 'isize' and 'char' to 'u8'. Do a
few cleanups on top thanks to that.
- Start to use 'derive(CoercePointee)' on Rust >= 1.84.0.
This is a major milestone on the path to build the kernel using
only stable Rust features. In particular, previously we were using
the unstable features 'coerce_unsized', 'dispatch_from_dyn' and
'unsize', and now we will use the new 'derive_coerce_pointee' one,
which is on track to stabilization. This new feature is a macro
that essentially expands into code that internally uses the
unstable features that we were using before, without having to
expose those.
With it, stable Rust users, including the kernel, will be able to
build custom smart pointers that work with trait objects, e.g.:
fn f(p: &Arc<dyn Display>) {
pr_info!("{p}\n");
}
let a: Arc<dyn Display> = Arc::new(42i32, GFP_KERNEL)?;
let b: Arc<dyn Display> = Arc::new("hello there", GFP_KERNEL)?;
f(&a); // Prints "42".
f(&b); // Prints "hello there".
Together with the 'arbitrary_self_types' feature that we started
using in the previous cycle, using our custom smart pointers like
'Arc' will eventually only rely in stable Rust.
- Introduce 'PROCMACROLDFLAGS' environment variable to allow to link
Rust proc macros using different flags than those used for linking
Rust host programs (e.g. when 'rustc' uses a different C library
than the host programs' one), which Android needs.
- Help kernel builds under macOS with Rust enabled by accomodating
other naming conventions for dynamic libraries (i.e. '.so' vs.
'.dylib') which are used for Rust procedural macros. The actual
support for macOS (i.e. the rest of the pieces needed) is provided
out-of-tree by others, following the policy used for other parts of
the kernel by Kbuild.
- Run Clippy for 'rusttest' code too and clean the bits it spotted.
- Provide Clippy with the minimum supported Rust version to improve
the suggestions it gives.
- Document 'bindgen' 0.71.0 regression.
'kernel' crate:
- 'build_error!': move users of the hidden function to the documented
macro, prevent such uses in the future by moving the function
elsewhere and add the macro to the prelude.
- 'types' module: add improved version of 'ForeignOwnable::borrow_mut'
(which was removed in the past since it was problematic); change
'ForeignOwnable' pointer type to '*mut'.
- 'alloc' module: implement 'Display' for 'Box' and align the 'Debug'
implementation to it; add example (doctest) for 'ArrayLayout::new()'
- 'sync' module: document 'PhantomData' in 'Arc'; use
'NonNull::new_unchecked' in 'ForeignOwnable for Arc' impl.
- 'uaccess' module: accept 'Vec's with different allocators in
'UserSliceReader::read_all'.
- 'workqueue' module: enable run-testing a couple more doctests.
- 'error' module: simplify 'from_errno()'.
- 'block' module: fix formatting in code documentation (a lint to catch
these is being implemented).
- Avoid 'unwrap()'s in doctests, which also improves the examples by
showing how kernel code is supposed to be written.
- Avoid 'as' casts with 'cast{,_mut}' calls which are a bit safer.
And a few other cleanups"
* tag 'rust-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (32 commits)
kbuild: rust: add PROCMACROLDFLAGS
rust: uaccess: generalize userSliceReader to support any Vec
rust: kernel: add improved version of `ForeignOwnable::borrow_mut`
rust: kernel: reorder `ForeignOwnable` items
rust: kernel: change `ForeignOwnable` pointer to mut
rust: arc: split unsafe block, add missing comment
rust: types: avoid `as` casts
rust: arc: use `NonNull::new_unchecked`
rust: use derive(CoercePointee) on rustc >= 1.84.0
rust: alloc: add doctest for `ArrayLayout::new()`
rust: init: update `stack_try_pin_init` examples
rust: error: import `kernel`'s `LayoutError` instead of `core`'s
rust: str: replace unwraps with question mark operators
rust: page: remove unnecessary helper function from doctest
rust: rbtree: remove unwrap in asserts
rust: init: replace unwraps with question mark operators
rust: use host dylib naming convention to support macOS
rust: add `build_error!` to the prelude
rust: kernel: move `build_error` hidden function to prevent mistakes
rust: use the `build_error!` macro, not the hidden function
...
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>
Because the `macros` crate exposes procedural macros, it must be
compiled as a dynamic library (so it can be loaded by the compiler at
compile-time).
Before this change the resulting artifact was always named
`libmacros.so`, which works on hosts where this matches the naming
convention for dynamic libraries. However the proper name on macOS would
be `libmacros.dylib`.
This turns out to matter even when the dependency is passed with a path
(`--extern macros=path/to/libmacros.so` rather than `--extern macros`)
because rustc uses the file name to infer the type of the library (see
link). This is because there's no way to specify both the path to and
the type of the external library via CLI flags. The compiler could
speculatively parse the file to determine its type, but it does not do
so today.
This means that libraries that match neither rustc's naming convention
for static libraries nor the platform's naming convention for dynamic
libraries are *rejected*.
The only solution I've found is to follow the host platform's naming
convention. This patch does that by querying the compiler to determine
the appropriate name for the artifact. This allows the kernel to build
with CONFIG_RUST=y on macOS.
Link: https://github.com/rust-lang/rust/blob/d829780/compiler/rustc_metadata/src/locator.rs#L728-L752
Tested-by: Daniel Gomez <da.gomez@samsung.com>
Co-developed-by: Fiona Behrens <me@kloenk.dev>
Signed-off-by: Fiona Behrens <me@kloenk.dev>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Tested-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20241216-b4-dylib-host-macos-v7-1-cfc507681447@gmail.com
[ Added `MAKEFLAGS=`s to avoid jobserver warnings. Removed space.
Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is new API which caters to the following requirements:
- Pack or unpack a large number of fields to/from a buffer with a small
code footprint. The current alternative is to open-code a large number
of calls to pack() and unpack(), or to use packing() to reduce that
number to half. But packing() is not const-correct.
- Use unpacked numbers stored in variables smaller than u64. This
reduces the rodata footprint of the stored field arrays.
- Perform error checking at compile time, rather than runtime, and return
void from the API functions. Because the C preprocessor can't generate
variable length code (loops), this is a bit tricky to do with macros.
To handle this, implement macros which sanity check the packed field
definitions based on their size. Finally, a single macro with a chain of
__builtin_choose_expr() is used to select the appropriate macros. We
enforce the use of ascending or descending order to avoid O(N^2) scaling
when checking for overlap. Note that the macros are written with care to
ensure that the compilers can correctly evaluate the resulting code at
compile time. In particular, care was taken with avoiding too many nested
statement expressions. Nested statement expressions trip up some
compilers, especially when passing down variables created in previous
statement expressions.
There are two key design choices intended to keep the overall macro code
size small. First, the definition of each CHECK_PACKED_FIELDS_N macro is
implemented recursively, by calling the N-1 macro. This avoids needing
the code to repeat multiple times.
Second, the CHECK_PACKED_FIELD macro enforces that the fields in the
array are sorted in order. This allows checking for overlap only with
neighboring fields, rather than the general overlap case where each field
would need to be checked against other fields.
The overlap checks use the first two fields to determine the order of the
remaining fields, thus allowing either ascending or descending order.
This enables drivers the flexibility to keep the fields ordered in which
ever order most naturally fits their hardware design and its associated
documentation.
The CHECK_PACKED_FIELDS macro is directly called from within pack_fields
and unpack_fields, ensuring that all drivers using the API receive the
benefits of the compile-time checks. Users do not need to directly call
any of the macros directly.
The CHECK_PACKED_FIELDS and its helper macros CHECK_PACKED_FIELDS_(0..50)
are generated using a simple C program in scripts/gen_packed_field_checks.c
This program can be compiled on demand and executed to generate the
macro code in include/linux/packing.h. This will aid in the event that a
driver needs more than 50 fields. The generator can be updated with a new
size, and used to update the packing.h header file. In practice, the ice
driver will need to support 27 fields, and the sja1105 driver will need
to support 0 fields. This on-demand generation avoids the need to modify
Kbuild. We do not anticipate the maximum number of fields to grow very
often.
- Reduced rodata footprint for the storage of the packed field arrays.
To that end, we have struct packed_field_u8 and packed_field_u16, which
define the fields with the associated type. More can be added as
needed (unlikely for now). On these types, the same generic pack_fields()
and unpack_fields() API can be used, thanks to the new C11 _Generic()
selection feature, which can call pack_fields_u8() or pack_fields_16(),
depending on the type of the "fields" array - a simplistic form of
polymorphism. It is evaluated at compile time which function will actually
be called.
Over time, packing() is expected to be completely replaced either with
pack() or with pack_fields().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Co-developed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241210-packing-pack-fields-and-ice-implementation-v10-3-ee56a47479ac@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
- 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
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Merge tag 'kbuild-v6.13' of 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()
...
Replace lz4c with lz4 for kernel image compression.
Although lz4 and lz4c are functionally similar, lz4c has been deprecated
upstream since 2018. Since as early as Ubuntu 16.04 and Fedora 25, lz4
and lz4c have been packaged together, making it safe to update the
requirement from lz4c to lz4.
Consequently, some distributions and build systems, such as OpenEmbedded,
have fully transitioned to using lz4. OpenEmbedded core adopted this
change in commit fe167e082cbd ("bitbake.conf: require lz4 instead of
lz4c"), causing compatibility issues when building the mainline kernel
in the latest OpenEmbedded environment, as seen in the errors below.
This change also updates the LZ4 compression commands to make it backward
compatible by replacing stdin and stdout with the '-' option, due to some
unclear reason, the stdout keyword does not work for lz4 and '-' works for
both. In addition, this modifies the legacy '-c1' with '-9' which is also
compatible with both. This fixes the mainline kernel build failures with
the latest master OpenEmbedded builds associated with the mentioned
compatibility issues.
LZ4 arch/arm/boot/compressed/piggy_data
/bin/sh: 1: lz4c: not found
...
...
ERROR: oe_runmake failed
Link: https://github.com/lz4/lz4/pull/553
Suggested-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Parth Pancholi <parth.pancholi@toradex.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This rule is unnecessary because you can generate foo/bar.symtypes
as a side effect using:
$ make KBUILD_SYMTYPES=1 foo/bar.o
While compiling *.o is slower than preprocessing, the impact is
negligible. I prioritize keeping the code simpler.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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>
When Kbuild starts building in a separate output directory, it generates
a wrapper Makefile, allowing you to invoke 'make' from the output
directory.
This commit makes it more convenient, so you can invoke 'make' without
M= or MO=.
First, you need to build external modules in a separate directory:
$ make M=/path/to/module/source/dir MO=/path/to/module/build/dir
Once the wrapper Makefile is generated in /path/to/module/build/dir,
you can proceed as follows:
$ cd /path/to/module/build/dir
$ make
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Keep the consistent behavior when this Makefile is invoked from another
directory.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
This commit makes -fmacro-prefix-map work for external modules built in
a separate output directory. It improves the reproducibility of external
modules and provides the benefits described in commit a73619a845
("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path").
When building_out_of_srctree is not defined (e.g., when the kernel or
external module is built in the source directory), this option is
unnecessary.
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>
With the previous changes, $(extmod_prefix), $(MODORDER), and
$(MODULES_NSDEPS) are constant. (empty, modules.order, and
modules.nsdeps, respectively).
Remove these variables and hard-code their values.
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>
Highlights for this merge window:
* The whole caching of module code into huge pages by Mike Rapoport is going
in through Andrew Morton's tree due to some other code dependencies. That's
really the biggest highlight for Linux kernel modules in this release. With
it we share huge pages for modules, starting off with x86. Expect to see that
soon through Andrew!
* Helge Deller addressed some lingering low hanging fruit alignment
enhancements by. It is worth pointing out that from his old patch series
I dropped his vmlinux.lds.h change at Masahiro's request as he would
prefer this to be specified in asm code [0].
[0] https://lore.kernel.org/all/20240129192644.3359978-5-mcgrof@kernel.org/T/#m9efef5e700fbecd28b7afb462c15eed8ba78ef5a
* Matthew Maurer and Sami Tolvanen have been tag teaming to help
get us closer to a modversions for Rust. In this cycle we take in
quite a lot of the refactoring for ELF validation. I expect modversions
for Rust will be merged by v6.14 as that code is mostly ready now.
* Adds a new modules selftests: kallsyms which helps us tests find_symbol()
and the limits of kallsyms on Linux today.
* We have a realtime mailing list to kernel-ci testing for modules now
which relies and combines patchwork, kpd and kdevops:
- https://patchwork.kernel.org/project/linux-modules/list/
- https://github.com/linux-kdevops/kdevops/blob/main/docs/kernel-ci/README.md
- https://github.com/linux-kdevops/kdevops/blob/main/docs/kernel-ci/kernel-ci-kpd.md
- https://github.com/linux-kdevops/kdevops/blob/main/docs/kernel-ci/linux-modules-kdevops-ci.md
If you want to help avoid Linux kernel modules regressions, now its simple,
just add a new Linux modules sefltests under tools/testing/selftests/module/
That is it. All new selftests will be used and leveraged automatically by
the CI.
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Merge tag 'modules-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux
Pull modules updates from Luis Chamberlain:
- The whole caching of module code into huge pages by Mike Rapoport is
going in through Andrew Morton's tree due to some other code
dependencies. That's really the biggest highlight for Linux kernel
modules in this release. With it we share huge pages for modules,
starting off with x86. Expect to see that soon through Andrew!
- Helge Deller addressed some lingering low hanging fruit alignment
enhancements by. It is worth pointing out that from his old patch
series I dropped his vmlinux.lds.h change at Masahiro's request as he
would prefer this to be specified in asm code [0].
[0] https://lore.kernel.org/all/20240129192644.3359978-5-mcgrof@kernel.org/T/#m9efef5e700fbecd28b7afb462c15eed8ba78ef5a
- Matthew Maurer and Sami Tolvanen have been tag teaming to help get us
closer to a modversions for Rust. In this cycle we take in quite a
lot of the refactoring for ELF validation. I expect modversions for
Rust will be merged by v6.14 as that code is mostly ready now.
- Adds a new modules selftests: kallsyms which helps us tests
find_symbol() and the limits of kallsyms on Linux today.
- We have a realtime mailing list to kernel-ci testing for modules now
which relies and combines patchwork, kpd and kdevops:
https://patchwork.kernel.org/project/linux-modules/list/https://github.com/linux-kdevops/kdevops/blob/main/docs/kernel-ci/README.mdhttps://github.com/linux-kdevops/kdevops/blob/main/docs/kernel-ci/kernel-ci-kpd.mdhttps://github.com/linux-kdevops/kdevops/blob/main/docs/kernel-ci/linux-modules-kdevops-ci.md
If you want to help avoid Linux kernel modules regressions, now its
simple, just add a new Linux modules sefltests under
tools/testing/selftests/module/ That is it. All new selftests will be
used and leveraged automatically by the CI.
* tag 'modules-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
tests/module/gen_test_kallsyms.sh: use 0 value for variables
scripts: Remove export_report.pl
selftests: kallsyms: add MODULE_DESCRIPTION
selftests: add new kallsyms selftests
module: Reformat struct for code style
module: Additional validation in elf_validity_cache_strtab
module: Factor out elf_validity_cache_strtab
module: Group section index calculations together
module: Factor out elf_validity_cache_index_str
module: Factor out elf_validity_cache_index_sym
module: Factor out elf_validity_cache_index_mod
module: Factor out elf_validity_cache_index_info
module: Factor out elf_validity_cache_secstrings
module: Factor out elf_validity_cache_sechdrs
module: Factor out elf_validity_ehdr
module: Take const arg in validate_section_offset
modules: Add missing entry for __ex_table
modules: Ensure 64-bit alignment on __ksymtab_* sections
$(KBUILD_OUTPUT) specifies the output directory of kernel builds.
Use a more generic name, 'output', to better reflect this code hunk in
the context of external module builds.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
'objtree' refers to the top of the output directory of kernel builds.
Rename abs_objtree to a more generic name, to better reflect its use in
the context of external module builds.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
$(objtree) refers to the top of the output directory of kernel builds.
This commit adds the explicit $(objtree)/ prefix to build artifacts
needed for building external modules.
This change has no immediate impact, as the top-level Makefile
currently defines:
objtree := .
This commit prepares for supporting the building of external modules
in a different directory.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Kbuild changes the working directory until it matches $(abs_objtree).
When $(need-sub-make) is empty, $(abs_objtree) is the same as $(CURDIR).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Add the build support for using Clang's Propeller optimizer. Like
AutoFDO, Propeller uses hardware sampling to gather information
about the frequency of execution of different code paths within a
binary. This information is then used to guide the compiler's
optimization decisions, resulting in a more efficient binary.
The support requires a Clang compiler LLVM 19 or later, and the
create_llvm_prof tool
(https://github.com/google/autofdo/releases/tag/v0.30.1). This
commit is limited to x86 platforms that support PMU features
like LBR on Intel machines and AMD Zen3 BRS.
Here is an example workflow for building an AutoFDO+Propeller
optimized kernel:
1) Build the kernel on the host machine, with AutoFDO and Propeller
build config
CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y
then
$ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo_profile>
“<autofdo_profile>” is the profile collected when doing a non-Propeller
AutoFDO build. This step builds a kernel that has the same optimization
level as AutoFDO, plus a metadata section that records basic block
information. This kernel image runs as fast as an AutoFDO optimized
kernel.
2) Install the kernel on test/production machines.
3) Run the load tests. The '-c' option in perf specifies the sample
event period. We suggest using a suitable prime number,
like 500009, for this purpose.
For Intel platforms:
$ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> \
-o <perf_file> -- <loadtest>
For AMD platforms:
The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2
# To see if Zen3 support LBR:
$ cat proc/cpuinfo | grep " brs"
# To see if Zen4 support LBR:
$ cat proc/cpuinfo | grep amd_lbr_v2
# If the result is yes, then collect the profile using:
$ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \
-N -b -c <count> -o <perf_file> -- <loadtest>
4) (Optional) Download the raw perf file to the host machine.
5) Generate Propeller profile:
$ create_llvm_prof --binary=<vmlinux> --profile=<perf_file> \
--format=propeller --propeller_output_module_name \
--out=<propeller_profile_prefix>_cc_profile.txt \
--propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
“create_llvm_prof” is the profile conversion tool, and a prebuilt
binary for linux can be found on
https://github.com/google/autofdo/releases/tag/v0.30.1 (can also build
from source).
"<propeller_profile_prefix>" can be something like
"/home/user/dir/any_string".
This command generates a pair of Propeller profiles:
"<propeller_profile_prefix>_cc_profile.txt" and
"<propeller_profile_prefix>_ld_profile.txt".
6) Rebuild the kernel using the AutoFDO and Propeller profile files.
CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y
and
$ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo_profile> \
CLANG_PROPELLER_PROFILE_PREFIX=<propeller_profile_prefix>
Co-developed-by: Han Shen <shenhan@google.com>
Signed-off-by: Han Shen <shenhan@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Sriraman Tallam <tmsriram@google.com>
Suggested-by: Krzysztof Pszeniczny <kpszeniczny@google.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Stephane Eranian <eranian@google.com>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Toolchain and infrastructure:
- Enable a series of lints, including safety-related ones, e.g. the
compiler will now warn about missing safety comments, as well as
unnecessary ones. How safety documentation is organized is a frequent
source of review comments, thus having the compiler guide new
developers on where they are expected (and where not) is very nice.
- Start using '#[expect]': an interesting feature in Rust (stabilized
in 1.81.0) that makes the compiler warn if an expected warning was
_not_ emitted. This is useful to avoid forgetting cleaning up locally
ignored diagnostics ('#[allow]'s).
- Introduce '.clippy.toml' configuration file for Clippy, the Rust
linter, which will allow us to tweak its behaviour. For instance, our
first use cases are declaring a disallowed macro and, more
importantly, enabling the checking of private items.
- Lints-related fixes and cleanups related to the items above.
- Migrate from 'receiver_trait' to 'arbitrary_self_types': to get the
kernel into stable Rust, one of the major pieces of the puzzle is the
support to write custom types that can be used as 'self', i.e. as
receivers, since the kernel needs to write types such as 'Arc' that
common userspace Rust would not. 'arbitrary_self_types' has been
accepted to become stable, and this is one of the steps required to
get there.
- Remove usage of the 'new_uninit' unstable feature.
- Use custom C FFI types. Includes a new 'ffi' crate to contain our
custom mapping, instead of using the standard library 'core::ffi'
one. The actual remapping will be introduced in a later cycle.
- Map '__kernel_{size_t,ssize_t,ptrdiff_t}' to 'usize'/'isize' instead
of 32/64-bit integers.
- Fix 'size_t' in bindgen generated prototypes of C builtins.
- Warn on bindgen < 0.69.5 and libclang >= 19.1 due to a double issue
in the projects, which we managed to trigger with the upcoming
tracepoint support. It includes a build test since some distributions
backported the fix (e.g. Debian -- thanks!). All major distributions
we list should be now OK except Ubuntu non-LTS.
'macros' crate:
- Adapt the build system to be able run the doctests there too; and
clean up and enable the corresponding doctests.
'kernel' crate:
- Add 'alloc' module with generic kernel allocator support and remove
the dependency on the Rust standard library 'alloc' and the extension
traits we used to provide fallible methods with flags.
Add the 'Allocator' trait and its implementations '{K,V,KV}malloc'.
Add the 'Box' type (a heap allocation for a single value of type 'T'
that is also generic over an allocator and considers the kernel's GFP
flags) and its shorthand aliases '{K,V,KV}Box'. Add 'ArrayLayout'
type. Add 'Vec' (a contiguous growable array type) and its shorthand
aliases '{K,V,KV}Vec', including iterator support.
For instance, now we may write code such as:
let mut v = KVec::new();
v.push(1, GFP_KERNEL)?;
assert_eq!(&v, &[1]);
Treewide, move as well old users to these new types.
- 'sync' module: add global lock support, including the
'GlobalLockBackend' trait; the 'Global{Lock,Guard,LockedBy}' types
and the 'global_lock!' macro. Add the 'Lock::try_lock' method.
- 'error' module: optimize 'Error' type to use 'NonZeroI32' and make
conversion functions public.
- 'page' module: add 'page_align' function.
- Add 'transmute' module with the existing 'FromBytes' and 'AsBytes'
traits.
- 'block::mq::request' module: improve rendered documentation.
- 'types' module: extend 'Opaque' type documentation and add simple
examples for the 'Either' types.
drm/panic:
- Clean up a series of Clippy warnings.
Documentation:
- Add coding guidelines for lints and the '#[expect]' feature.
- Add Ubuntu to the list of distributions in the Quick Start guide.
MAINTAINERS:
- Add Danilo Krummrich as maintainer of the new 'alloc' module.
And a few other small cleanups and fixes.
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Merge tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux
Pull rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Enable a series of lints, including safety-related ones, e.g. the
compiler will now warn about missing safety comments, as well as
unnecessary ones. How safety documentation is organized is a
frequent source of review comments, thus having the compiler guide
new developers on where they are expected (and where not) is very
nice.
- Start using '#[expect]': an interesting feature in Rust (stabilized
in 1.81.0) that makes the compiler warn if an expected warning was
_not_ emitted. This is useful to avoid forgetting cleaning up
locally ignored diagnostics ('#[allow]'s).
- Introduce '.clippy.toml' configuration file for Clippy, the Rust
linter, which will allow us to tweak its behaviour. For instance,
our first use cases are declaring a disallowed macro and, more
importantly, enabling the checking of private items.
- Lints-related fixes and cleanups related to the items above.
- Migrate from 'receiver_trait' to 'arbitrary_self_types': to get the
kernel into stable Rust, one of the major pieces of the puzzle is
the support to write custom types that can be used as 'self', i.e.
as receivers, since the kernel needs to write types such as 'Arc'
that common userspace Rust would not. 'arbitrary_self_types' has
been accepted to become stable, and this is one of the steps
required to get there.
- Remove usage of the 'new_uninit' unstable feature.
- Use custom C FFI types. Includes a new 'ffi' crate to contain our
custom mapping, instead of using the standard library 'core::ffi'
one. The actual remapping will be introduced in a later cycle.
- Map '__kernel_{size_t,ssize_t,ptrdiff_t}' to 'usize'/'isize'
instead of 32/64-bit integers.
- Fix 'size_t' in bindgen generated prototypes of C builtins.
- Warn on bindgen < 0.69.5 and libclang >= 19.1 due to a double issue
in the projects, which we managed to trigger with the upcoming
tracepoint support. It includes a build test since some
distributions backported the fix (e.g. Debian -- thanks!). All
major distributions we list should be now OK except Ubuntu non-LTS.
'macros' crate:
- Adapt the build system to be able run the doctests there too; and
clean up and enable the corresponding doctests.
'kernel' crate:
- Add 'alloc' module with generic kernel allocator support and remove
the dependency on the Rust standard library 'alloc' and the
extension traits we used to provide fallible methods with flags.
Add the 'Allocator' trait and its implementations '{K,V,KV}malloc'.
Add the 'Box' type (a heap allocation for a single value of type
'T' that is also generic over an allocator and considers the
kernel's GFP flags) and its shorthand aliases '{K,V,KV}Box'. Add
'ArrayLayout' type. Add 'Vec' (a contiguous growable array type)
and its shorthand aliases '{K,V,KV}Vec', including iterator
support.
For instance, now we may write code such as:
let mut v = KVec::new();
v.push(1, GFP_KERNEL)?;
assert_eq!(&v, &[1]);
Treewide, move as well old users to these new types.
- 'sync' module: add global lock support, including the
'GlobalLockBackend' trait; the 'Global{Lock,Guard,LockedBy}' types
and the 'global_lock!' macro. Add the 'Lock::try_lock' method.
- 'error' module: optimize 'Error' type to use 'NonZeroI32' and make
conversion functions public.
- 'page' module: add 'page_align' function.
- Add 'transmute' module with the existing 'FromBytes' and 'AsBytes'
traits.
- 'block::mq::request' module: improve rendered documentation.
- 'types' module: extend 'Opaque' type documentation and add simple
examples for the 'Either' types.
drm/panic:
- Clean up a series of Clippy warnings.
Documentation:
- Add coding guidelines for lints and the '#[expect]' feature.
- Add Ubuntu to the list of distributions in the Quick Start guide.
MAINTAINERS:
- Add Danilo Krummrich as maintainer of the new 'alloc' module.
And a few other small cleanups and fixes"
* tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux: (82 commits)
rust: alloc: Fix `ArrayLayout` allocations
docs: rust: remove spurious item in `expect` list
rust: allow `clippy::needless_lifetimes`
rust: warn on bindgen < 0.69.5 and libclang >= 19.1
rust: use custom FFI integer types
rust: map `__kernel_size_t` and friends also to usize/isize
rust: fix size_t in bindgen prototypes of C builtins
rust: sync: add global lock support
rust: macros: enable the rest of the tests
rust: macros: enable paste! use from macro_rules!
rust: enable macros::module! tests
rust: kbuild: expand rusttest target for macros
rust: types: extend `Opaque` documentation
rust: block: fix formatting of `kernel::block::mq::request` module
rust: macros: fix documentation of the paste! macro
rust: kernel: fix THIS_MODULE header path in ThisModule doc comment
rust: page: add Rust version of PAGE_ALIGN
rust: helpers: remove unnecessary header includes
rust: exports: improve grammar in commentary
drm/panic: allow verbose version check
...
In beta Clippy (i.e. Rust 1.83.0), the `needless_lifetimes` lint has
been extended [1] to suggest eliding `impl` lifetimes, e.g.
error: the following explicit lifetimes could be elided: 'a
--> rust/kernel/list.rs:647:6
|
647 | impl<'a, T: ?Sized + ListItem<ID>, const ID: u64> FusedIterator for Iter<'a, T, ID> {}
| ^^ ^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
= note: `-D clippy::needless-lifetimes` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::needless_lifetimes)]`
help: elide the lifetimes
|
647 - impl<'a, T: ?Sized + ListItem<ID>, const ID: u64> FusedIterator for Iter<'a, T, ID> {}
647 + impl<T: ?Sized + ListItem<ID>, const ID: u64> FusedIterator for Iter<'_, T, ID> {}
A possibility would have been to clean them -- the RFC patch [2] did
this, while asking if we wanted these cleanups. There is an open issue
[3] in Clippy about being able to differentiate some of the new cases,
e.g. those that do not involve introducing `'_`. Thus it seems others
feel similarly.
Thus, for the time being, we decided to `allow` the lint.
Link: https://github.com/rust-lang/rust-clippy/pull/13286 [1]
Link: https://lore.kernel.org/rust-for-linux/20241012231300.397010-1-ojeda@kernel.org/ [2]
Link: https://github.com/rust-lang/rust-clippy/issues/13514 [3]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20241116181538.369355-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kees Cook