Last references were removed in http://r.android.com/3552603 and
http://r.android.com/3552602.
Since mixed-build-prefix is no longer used, we can safely remove its
definition and export.
Bug: 205893923
Test: tools/bazel build //common-modules/virtual-device:virtual_device_x86_64
Change-Id: I467d7a01648bbd079640e645e09b9f5edbdee3b3
Signed-off-by: Ulises Mendez Martinez <umendez@google.com>
This variable was removed upstream in commit bad6beb2c0 ("kbuild:
remove extmod_prefix, MODORDER, MODULES_NSDEPS variables"). However, it
was mistakenly kept during a merge conflict resolution. Drop it!
Fixes: f9d4616300 ("Merge 'Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild'")
Change-Id: I8e5b6c10ab82b8ccc16a1bb575b96c3f68f1f9e5
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Pull interrupt core updates from Thomas Gleixner:
- Rework of /proc/interrupt handling:
/proc/interrupts was subject to micro optimizations for a long time,
but most of the low hanging fruit was left on the table. This rework
addresses the major time consuming issues:
- Printing a long series of zeros one by one via a format string
instead of counting subsequent zeros and emitting a string
constant.
- Simplify and cache the conditions whether interrupts should be
printed
- Use a proper iteration over the interrupt descriptor xarray
instead of walking and testing one by one.
- Provide helper functions for the architecture code to emit the
architecture specific counters
- Convert the counter structure in x86 to an array, which
simplifies the output and add mechanisms to suppress unused
architecture interrupts, which just occupy space for nothing.
Adopt the new core mechanisms.
This adjusts the gdb scripts related to interrupt counter statistics
to work with the new mechanisms.
- Prevent a string overflow in the /proc/irq/$N/ directory name
creation code.
* tag 'irq-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
x86/irq: Add missing 's' back to thermal event printout
genirq/proc: Speed up /proc/interrupts iteration
genirq/proc: Runtime size the chip name
genirq: Expose irq_find_desc_at_or_after() in core code
genirq: Add rcuref count to struct irq_desc
genirq/proc: Increase default interrupt number precision to four
genirq: Calculate precision only when required
genirq: Cache the condition for /proc/interrupts exposure
genirq/manage: Make NMI cleanup RT safe
genirq: Expose nr_irqs in core code
scripts/gdb: Update x86 interrupts to the array based storage
x86/irq: Move IOAPIC misrouted and PIC/APIC error counts into irq_stats
x86/irq: Suppress unlikely interrupt stats by default
x86/irq: Make irqstats array based
genirq/proc: Utilize irq_desc::tot_count to avoid evaluation
genirq/proc: Avoid formatting zero counts in /proc/interrupts
x86/irq: Optimize interrupts decimals printing
genirq/proc: Size interrupt directory names for 10-digit interrupt numbers
Pull Rust updates from Miguel Ojeda:
"This one is big due to the vendoring of the `zerocopy` library, which
allows us to replace a bunch of `unsafe` code dealing with conversions
between byte sequences and other types with safe alternatives. More
details on that below (and in its merge commit).
Toolchain and infrastructure:
- Introduce support for the 'zerocopy' library [1][2]:
Fast, safe, compile error. Pick two.
Zerocopy makes zero-cost memory manipulation effortless. We write
`unsafe` so you don't have to.
It essentially provides derivable traits (e.g. 'FromBytes') and
macros (e.g. 'transmute!') for safely converting between byte
sequences and other types. Having such support allows us to remove
some 'unsafe' code.
It is among the most downloaded Rust crates and it is also used by
the Rust compiler itself.
It is licensed under "BSD-2-Clause OR Apache-2.0 OR MIT".
The crates are imported essentially as-is (only +2/-3 lines needed
to be adapted), plus SPDX identifiers. Upstream has since added the
SPDX identifiers as well as one of the tweaks at my request, thus
reducing our future diffs on updates -- I keep the details in one
of our usual live lists [3].
In total, it is about ~39k lines added, ~32k without counting
'benches/' which are just for documentation purposes.
The series includes a few Kbuild and rust-analyzer improvements and
an example patch using it in Nova, removing one 'unsafe impl'.
I checked that the codegen of an isolated example function (similar
to the Nova patch on top) is essentially identical. It also turns
out that (for that particular case) the 'zerocopy' version, even
with 'debug-assertions' enabled, has no remaining panics, unlike a
few in the current code (since the compiler can prove the remaining
'ub_checks' statically).
So their "fast, safe" does indeed check out -- at least in that
case.
- Support AutoFDO. This allows Rust code to be profiled and optimized
based on the profile. Tested with Rust Binder: ~13% slower without
AutoFDO in the binderAddInts benchmark (using an app-launch
benchmark for the profile).
- Support Software Tag-Based KASAN.
In addition, fix KASAN Kconfig by requiring Clang.
- Add Kconfig options for each existing Rust KUnit test suite, such
as 'CONFIG_RUST_BITMAP_KUNIT_TEST'.
They are placed within a new menu, 'CONFIG_RUST_KUNIT_TESTS', in
the new 'rust/kernel/Kconfig.test' file.
- Support the upcoming Rust 1.98.0 release (expected 2026-08-20):
lint cleanups and an unstable flag rename.
- Disable 'rustdoc' documentation inlining for all prelude items,
which bloats the generated documentation.
- Ignore (in Git) and clean (in Kbuild) the (rarely) 'rustc'-generated
'*.long-type-*.txt' files.
'kernel' crate:
- Add new 'bitfield' module with the 'bitfield!' macro (extracted
from the existing 'register!' one), which declares integer types
that are split into distinct bit fields of arbitrary length.
Each field is a 'Bounded' of the appropriate bit width (ensuring
values are properly validated and avoiding implicit data loss) and
gets several generated getters and setters (infallible, 'const' and
fallible) as well as associated constants ('_MASK', '_SHIFT' and
'_RANGE'). It also supports fields that can be converted from/to
custom types, either fallibly ('?=>') or infallibly ('=>').
For instance:
bitfield! {
struct Rgb(u16) {
15:11 blue;
10:5 green;
4:0 red;
}
}
// Compile-time checks.
let color = Rgb::zeroed().with_const_green::<0x1f>();
assert_eq!(color.green(), 0x1f);
assert_eq!(color.into_raw(), 0x1f << Rgb::GREEN_SHIFT);
Add as well documentation and a test suite for it, as usual; and
update the 'register!' macro to use it.
It will be maintained by Alexandre Courbot (with Yury Norov as
reviewer) under a new 'MAINTAINERS' entry: 'RUST [BITFIELD]'.
- 'ptr' module: rework index projection syntax into keyworded syntax
and introduce panicking variant.
The keyword syntax ('build:', 'try:', 'panic:') is more explicit
and paves the way of perhaps adding more flavors in the future,
e.g. an 'unsafe' index projection.
For instance, projections now look like this:
fn f(p: *const [u8; 32]) -> Result {
// Ok, within bounds, checked at build time.
project!(p, [build: 1]);
// Build error.
project!(p, [build: 128]);
// `OutOfBound` runtime error (convertible to `ERANGE`).
project!(p, [try: 128]);
// Runtime panic.
project!(p, [panic: 128]);
Ok(())
}
Update as well the users, which now look like e.g.
// Pointer to the first entry of the GSP message queue.
let data = project!(self.0.as_ptr(), .gspq.msgq.data[build: 0]);
- 'build_assert' module: make the module the home of its macros
instead of rendering them twice.
- 'sync' module: add 'UniqueArc::as_ptr()' associated function.
- 'alloc' module:
- Fix the 'Vec::reserve()' doctest to properly account for the
existing vector length in the capacity assertion.
- Fix an incorrect operator in the 'Vec::extend_with()' 'SAFETY'
comment; add a doc test demonstrating basic usage and the
zero-length case.
- Clean imports across several modules to follow the "kernel
vertical" import style in order to minimize conflicts.
'pin-init' crate:
- User visible changes:
- Do not generate 'non_snake_case' warnings for identifiers that
are syntactically just users of a field name. This would allow
all '#[allow(non_snake_case)]' in nova-core to be removed,
which Gary will send to the nova tree next cycle.
- Filter non-cfg attributes out properly in derived structs. This
improves pin-init compatibility with other derive macros.
- Insert projection types' where clause properly.
- Other changes:
- Bump MSRV to 1.82, plus associated cleanups.
- Overhaul how init slots are projected. The new approach is
easier to justify with safety comments.
- Mark more functions as inline, which should help mitigate the
super-long symbol name issue due to lack of inlining.
rust-analyzer:
- Support '--envs' for passing env vars for crates like 'zerocopy'.
'MAINTAINERS':
- Add the following reviewers to the 'RUST' entry:
- Daniel Almeida
- Tamir Duberstein
- Alexandre Courbot
- Onur Özkan
They have been involved in the Rust for Linux project for about 7
collective years and bring expertise across several domains, which
will be very useful to have around in the future.
Thanks everyone for stepping up!
And some other fixes, cleanups and improvements"
Link: https://github.com/google/zerocopy [1]
Link: https://docs.rs/zerocopy [2]
Link: https://github.com/Rust-for-Linux/linux/issues/1239 [3]
* tag 'rust-7.2' of gitolite.kernel.org:pub/scm/linux/kernel/git/ojeda/linux: (86 commits)
MAINTAINERS: add Onur Özkan as Rust reviewer
MAINTAINERS: add Alexandre Courbot as Rust reviewer
MAINTAINERS: add Tamir Duberstein as Rust reviewer
MAINTAINERS: add Daniel Almeida as Rust reviewer
kbuild: rust: clean `zerocopy-derive` in `mrproper`
rust: make `build_assert` module the home of related macros
rust: str: clean unused import for Rust >= 1.98
rust: str: use the "kernel vertical" imports style
rust: aref: use the "kernel vertical" imports style
rust: page: use the "kernel vertical" imports style
gpu: nova-core: firmware: parse `FalconUCodeDescV2` via `zerocopy`
rust: prelude: add `zerocopy{,_derive}::FromBytes`
rust: zerocopy-derive: enable support in kbuild
rust: zerocopy-derive: add `README.md`
rust: zerocopy-derive: avoid generating non-ASCII identifiers
rust: zerocopy-derive: add SPDX License Identifiers
rust: zerocopy-derive: import crate
rust: zerocopy: enable support in kbuild
rust: zerocopy: add `README.md`
rust: zerocopy: remove float `Display` support
...
Pull RCU updates from Uladzislau Rezki:
"Torture test updates:
- Improve kvm-series.sh script by adding examples in its header
comment
- Lazy RCU is more fully tested now by replacing call_rcu_hurry()
with call_rcu() and doing rcu_barrier() to motivate lazy callbacks
during a stutter pause
- Add more synonyms for the "--do-normal" group of torture.sh
command-line arguments
Misc changes:
- Reduce stack usage of nocb_gp_wait() to address frame size warning
when built with CONFIG_UBSAN_ALIGNMENT
- The synchronize_rcu() call can detect the flood and latches a
normal/default path temporary switching to wait_rcu_gp() path
- Document using rcu_access_pointer() to fetch the old pointer for
lockless cmpxchg() updates
- Simplify some RCU code using clamp_val()
- Fix a kerneldoc header comment typo in srcu_down_read_fast()"
* tag 'rcu.release.v7.2' of gitolite.kernel.org:pub/scm/linux/kernel/git/rcu/linux:
rcu/nocb: reduce stack usage in nocb_gp_wait()
rcu-tasks: Fix possible boot-time tests failed for the call_rcu_tasks()
rcu: Latch normal synchronize_rcu() path on flood
rcu: Document rcu_access_pointer() feeding into cmpxchg()
rcu: Simplify param_set_next_fqs_jiffies() by applying clamp_val()
rcu: Simplify rcu_do_batch() by applying clamp()
checkpatch: Undeprecate rcu_read_lock_trace() and rcu_read_unlock_trace()
srcu: Fix kerneldoc header comment typo in srcu_down_read_fast()
torture: Allow "norm" abbreviation for "normal"
torture: Improve kvm-series.sh header comment
torture: Add torture_sched_set_normal() for user-specified nice values
rcutorture: Fully test lazy RCU
Pull Kbuild / Kconfig updates from Nathan Chancellor:
"Kbuild:
- Remove broken module linking exclusion for BTF
- Add documentation around how offset header files work
- Include unstripped vDSO libraries in pacman packages
- Bump minimum version of LLVM for building the kernel to 17.0.1 and
clean up unnecessary workarounds
- Use a context manager in run-clang-tools
- Add dist macro value if present to release tag for RPM packages
- Detect and report truncated buf_printf() output in modpost
- Add __llvm_covfun and __llvm_covmap to section whitelist in modpost
- Support Clang's distributed ThinLTO mode
- Remove architecture specific configurations for AutoFDO and
Propeller to ease individual architecture maintenance
Kconfig:
- Add kconfig-sym-check target to look for dangling Kconfig symbol
references and invalid tristate literal values
- Harden against potential NULL pointer dereference
- Fix typo in Kconfig test comment"
* tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (31 commits)
kconfig: tests: fix typo in comment
kconfig: Remove the architecture specific config for Propeller
kconfig: Remove the architecture specific config for AutoFDO
modpost: Add __llvm_covfun and __llvm_covmap to section_white_list
kconfig: add kconfig-sym-check static checker
kbuild: Remove unnecessary 'T' modifier in cmd_ar_builtin_fixup
kbuild: distributed build support for Clang ThinLTO
kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
scripts: modpost: detect and report truncated buf_printf() output
kbuild: rpm-pkg: append %{?dist} macro to Release tag
run-clang-tools: run multiprocessing.Pool as context manager
compiler-clang.h: Drop explicit version number from "all" diagnostic macro
compiler-clang.h: Remove __cleanup -Wunused-variable workaround
kbuild: Remove check for broken scoping with clang < 17 in CC_HAS_ASM_GOTO_OUTPUT
x86/entry/vdso32: Remove conditional omission of '.cfi_offset eflags'
x86/module: Revert "Deal with GOT based stack cookie load on Clang < 17"
x86/build: Drop unnecessary '-ffreestanding' addition to KBUILD_CFLAGS
scripts/Makefile.warn: Drop -Wformat handling for clang < 16
riscv: Drop tautological condition from TOOLCHAIN_NEEDS_OLD_ISA_SPEC
riscv: Remove tautological condition from selection of ARCH_SUPPORTS_CFI
...
With all the new files in place and ready from the new crate, enable
the support for it in the build system.
In addition, skip formatting for this vendored crate.
Finally, there are no generated symbols expected from `zerocopy`, thus
skip adding the `exports` generation.
Link: https://patch.msgid.link/20260608141439.182634-13-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
A future commit adding `zerocopy` support will need to pass an environment
variable during its build.
Thus add support for an `--envs` parameter, similar to `--cfgs`, that
allows to pass a map of variables to set for a given crate.
This allows us to keep a single source of truth for those values.
No change intended in the generated `rust-project.json`.
Acked-by: Tamir Duberstein <tamird@kernel.org>
Link: https://patch.msgid.link/20260608141439.182634-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix 'rustc-option' (the Makefile one) when cross-compiling that
leads to build or boot failures in certain configs
- Work around a Rust compiler bug (already fixed for Rust 1.98.0)
thats lead to boot failures in certain configs due to missing
'uwtable' LLVM module flags
- Support a Rust compiler change (starting with Rust 1.98.0) in the
unstable target specification JSON files
- Forbid Rust + arm + KASAN configs, which do not build
'kernel' crate:
- Fix NOMMU build by adding a missing helper"
* tag 'rust-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: x86: support Rust >= 1.98.0 target spec
rust: arm64: set uwtable llvm module flag for CONFIG_UNWIND_TABLES
rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds
rust: kasan/kbuild: fix rustc-option when cross-compiling
ARM: Do not select HAVE_RUST when KASAN is enabled
Modpost emits hundreds of warnings when using Clang to build for ARCH=um
and CONFIG_GCOV=y. e.g.:
vmlinux (__llvm_covfun): unexpected non-allocatable section.
Did you forget to use "ax"/"aw" in a .S file?
Note that for example <linux/init.h> contains
section definitions for use in .S files.
For example, when we use LLVM for a kunit user mode build with coverage:
python3 tools/testing/kunit/kunit.py build --make_options LLVM=1 \
--kunitconfig=tools/testing/kunit/configs/default.config \
--kunitconfig=tools/testing/kunit/configs/coverage_uml.config
The behaviour occurs when building the kernel for ARCH=um with code
coverage enabled. The warnings come from modpost's check_sec_ref
function, which ensures no sections reference others that will be
discarded. covfun and covmap sections must reference __init and __exit
sections to collect coverage data, triggering the modpost warning.
To suppress these warnings, these section names have been added to
modpost's whitelist. This is unlikely to suppress legitimate warnings as
Clang will only insert these sections when building with coverage, and
can be assumed to manage these references safely.
Signed-off-by: James Lee <james@codeconstruct.com.au>
Link: https://patch.msgid.link/20260604-dev-coverage-patch-v1-1-9f9368253cb4@codeconstruct.com.au
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
The err_repeated_inc test was added with an expected stderr fixture
that does not match the diagnostic printed by kconfig.
Running "make testconfig" currently fails in that test even though the
parser reports the duplicated include correctly:
[stderr]
Kconfig.inc1:4: error: repeated inclusion of Kconfig.inc3
Kconfig.inc2:3: note: location of first inclusion of Kconfig.inc3
The fixture expects "Repeated" and "Location" with capital letters, but
the diagnostic emitted by scripts/kconfig/util.c uses lowercase words.
Update the fixture to match the real message.
Fixes: 102d712ded ("kconfig: Error out on duplicated kconfig inclusion")
Signed-off-by: Zhou Yuhang <zhouyuhang@kylinos.cn>
Tested-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260520070800.2265479-1-zhouyuhang1010@163.com
Signed-off-by: Nicolas Schier <nsc@kernel.org>
When the unused exports whitelist is provided, the symbol protection bit
is set for symbols not present in the unused exports whitelist.
The flag will be used in the following commit to prevent unsigned
modules from the using symbols other than those explicitly declared by
the such modules ahead of time.
Bug: 519119852
Change-Id: Ibddd628a8b1463397cc95d3d8f556b9bc82bf623
Signed-off-by: Siddharth Nayyar <sidnayyar@google.com>
Add 'make kconfig-sym-check', a static checker that finds Kconfig
symbols referenced in expressions (select, depends on, default, etc.)
but never defined via config/menuconfig anywhere in the tree. New
dangling symbols are reported as errors (exit 1) unless they are
listed in an exclusion file, e.g.
KCONFIG_SYM_CHECK_EXCLUDES=sym-check-excludes make kconfig-sym-check
The exclusion file lists one symbol per line; blank lines and lines
starting with '#' are ignored.
The checker also warns about uppercase N/Y/M used as tristate literal
values following the same logic as checkpatch.
This new static checker is the script used for [1] with a few
improvements to avoid some false positives.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216748 [1]
Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Julian Braha <julianbraha@gmail.com>
Tested-by: Nicolas Schier <nsc@kernel.org>
Acked-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260527142703.107110-1-andrew.jones@linux.dev
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
In cmd_ar_builtin_fixup, the 'T' modifier was added to '$(AR) mPi' to
work around a bug in llvm-ar that caused thin archives to be silently
converted to full archives [1]. Since commit 20c0989283 ("kbuild: Bump
minimum version of LLVM for building the kernel to 15.0.0"), all
supported versions of llvm-ar have this issue fixed, so the 'T' modifier
and comment can be removed.
Link: https://github.com/llvm/llvm-project/commit/d17c54d17de22d2961a04163f3dbc8e973de89b8 [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Starting with Rust 1.98.0 (expected 2026-08-20), the target spec will not
support `x86-softfloat` anymore [1]. Instead, `softfloat` should be used,
which is an alias. Otherwise, one gets:
error: error loading target specification: rustc-abi: invalid rustc abi: 'x86-softfloat'. allowed values: 'x86-sse2', 'softfloat' at line 3 column 32
|
= help: run `rustc --print target-list` for a list of built-in targets
Thus conditionally use one or the other depending on the version.
The alias has existed since Rust 1.95.0 (released 2026-04-16) [2], but
use the newer version instead to avoid changing how the build works for
existing compilers, at least until more testing takes place.
Cc: Ralf Jung <post@ralfj.de>
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/pull/157151 [1]
Link: https://github.com/rust-lang/rust/pull/151154 [2]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260530114925.260754-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Add distributed ThinLTO build support for the Linux kernel.
This new mode offers several advantages: (1) Increased
flexibility in handling user-specified build options.
(2) Improved user-friendliness for developers. (3) Greater
convenience for integrating with objtool and livepatch.
Note that "distributed" in this context refers to a term
that differentiates in-process ThinLTO builds by invoking
backend compilation through the linker, not necessarily
building in distributed environments.
Distributed ThinLTO is enabled via the
`CONFIG_LTO_CLANG_THIN_DIST` Kconfig option. For example:
> make LLVM=1 defconfig
> scripts/config -e LTO_CLANG_THIN_DIST
> make LLVM=1 oldconfig
> make LLVM=1 vmlinux -j <..>
The build flow proceeds in four stages:
1. Perform FE compilation, mirroring the in-process ThinLTO mode.
2. Thin-link the generated IR files and object files.
3. Find all IR files and perform BE compilation, using the flags
stored in the .*.o.cmd files.
4. Link the BE results to generate the final vmlinux.o.
NOTE: This patch currently implements the build for the main kernel
image (vmlinux) only. Kernel module support is planned for a
subsequent patch.
Tested on the following arch: x86, arm64, loongarch, and
riscv.
The earlier implementation details can be found here:
https://discourse.llvm.org/t/rfc-distributed-thinlto-build-for-kernel/85934
Signed-off-by: Rong Xu <xur@google.com>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Piotr Gorski <piotrgorski@cachyos.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260529185347.2418373-4-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
buf_printf() uses a fixed-size stack buffer. vsnprintf() returns the
number of bytes that *would* have been written to that buffer, which can
be larger than the size of said buffer if the formatted string is too
long.
The problem is that whenever this happens buf_printf() currently passes
this length, unchecked, to buf_write(), which silently reads past the
stack buffer and copies invalid data into the output buffer.
Fix this by detecting vsnprintf() failures and truncations before
appending to the output buffer, and report a fatal error instead of
producing corrupt symbol names.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://patch.msgid.link/20260527-nova-exports-v2-1-06de4c556d55@nvidia.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
The current minimum version of LLVM for building the kernel is 15.0.0.
However, there are two deficiencies compared to GCC that were fixed in
LLVM 17 that are starting to become more noticeable.
The first was a bug in LLVM's scope checker [1], where all labels in a
function were validated as potential targets of an asm goto statement,
even if they were not listed in the asm goto statement as targets. This
becomes particularly problematic when the cleanup attribute is used, as
asm goto(... : label_a);
...
label_a:
...
int var __free(foo);
asm goto(... : label_b);
...
label_b:
...
will trigger an error since the scope checker will complain that the
cleanup variable would be skipped when jumping from the first asm goto
to label_b (which obviously cannot happen). This issue was the catalyst
for commit e2ffa15b9b ("kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on
clang < 17"). Unfortunately, this issue is reproducible with regular asm
goto in addition to asm goto with outputs, so that change was not
entirely sufficient to avoid the issue altogether. As asm goto has
effectively been required since commit a0a12c3ed0 ("asm goto:
eradicate CC_HAS_ASM_GOTO") and the usage of the cleanup attribute
continues to grow across the tree, raising the minimum to a version that
avoids this issue altogether is a better long term solution than
attempting to workaround it at every spot where it happens.
The second issue is an incompatibility with GCC 8.1+ around variables
marked with const being valid constant expressions for _Static_assert
and other macros [2]. With GCC 8.1 being the minimum supported version
since commit 118c40b7b5 ("kbuild: require gcc-8 and binutils-2.30"),
this incompatibility becomes more of a maintenance burden since only
clang-15 and clang-16 are affected by it.
Looking at the clang version of various major distributions through
Docker images, no one should be left behind as a result of this bump, as
the old ones cannot clear the current minimum of 15.0.0.
archlinux:latest clang version 22.1.3
debian:oldoldstable-slim Debian clang version 11.0.1-2
debian:oldstable-slim Debian clang version 14.0.6
debian:stable-slim Debian clang version 19.1.7 (3+b1)
debian:testing-slim Debian clang version 21.1.8 (3+b1)
debian:unstable-slim Debian clang version 21.1.8 (7+b1)
fedora:42 clang version 20.1.8 (Fedora 20.1.8-4.fc42)
fedora:latest clang version 21.1.8 (Fedora 21.1.8-4.fc43)
fedora:44 clang version 22.1.1 (Fedora 22.1.1-2.fc44)
fedora:rawhide clang version 22.1.3 (Fedora 22.1.3-1.fc45)
opensuse/leap:latest clang version 17.0.6
opensuse/tumbleweed:latest clang version 21.1.8
ubuntu:jammy Ubuntu clang version 14.0.0-1ubuntu1.1
ubuntu:noble Ubuntu clang version 18.1.3 (1ubuntu1)
ubuntu:questing Ubuntu clang version 20.1.8 (0ubuntu4)
ubuntu:resolute Ubuntu clang version 21.1.8 (6ubuntu1)
17.0.1 is chosen as the minimum instead of 17.0.0 to ensure that the
particular version of LLVM 17 has the two aforementioned bugs fixed, as
the second was fixed during the 17.0.0 release candidate phase and it
was not until LLVM 18 that LLVM adopted the scheme of x.0.0 being a
prerelease version and x.1.0 is a release version [3] to help with
scenarios such as this.
Link: https://github.com/llvm/llvm-project/commit/f023f5cdb2e6c19026f04a15b5a935c041835d14 [1]
Link: https://github.com/llvm/llvm-project/commit/0b2d5b967d98375793897295d651f58f6fbd3034 [2]
Link: https://github.com/llvm/llvm-project/commit/4532617ae420056bf32f6403dde07fb99d276a49 [3]
Acked-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-1-b3b8cda46bdd@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This adds support for Software Tag-Based KASAN (KASAN_SW_TAGS) when
CONFIG_RUST is enabled. This requires that rustc includes support for
the kernel-hwaddress sanitizer, which is available since 1.96.0 [1].
Unlike with clang, we need to pass -Zsanitizer-recover in addition to
-Zsanitizer because the option is not implied automatically.
The kasan makefile uses different names for the flags depending on
whether CC is clang or gcc, but as we require that CC is clang when
using KASAN, we do not need to try to handle mixed gcc/llvm builds when
Rust is enabled.
Link: https://github.com/rust-lang/rust/pull/153049 [1]
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260408-kasan-rust-sw-tags-v3-2-e07964d14363@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This patch enables AutoFDO build support for Rust code within the Linux
kernel. This allows Rust code to be profiled and optimized based on the
profile.
The RUSTFLAGS variable was suffixed with *_AUTOFDO_CLANG to match the
naming of the config option, which is called CONFIG_AUTOFDO_CLANG.
This implementation has been verified in Android, first by inspecting
the object files and confirming that they look correct. After that,
it was verified as below:
1. Running the binderAddInts benchmark [1] with Rust Binder built as
rust_binder.ko module, using a Pixel 9 Pro.
2. Collecting a profile on a Pixel 10 Pro XL using the app-launch
benchmark, which starts different apps many times, on a device with
Rust Binder as a built-in kernel module. (C Binder was not present on
the device.)
3. Using the collected profile, run the binderAddInts benchmark again
with Rust Binder built both as a rust_binder.ko module, and as a
built-in kernel module.
4. In both cases, Rust Binder without AutoFDO was approximately 13%
slower than the AutoFDO optimized version. Built-in vs .ko did not
make a measurable performance difference.
All of the above was verified in conjunction with my helpers inlining
series [2], which confirmed that this worked correctly for helpers too
once [3] was fixed in the helpers inlining series.
Link: https://android.googlesource.com/platform/system/extras/+/920f089/tests/binder/benchmarks/binderAddInts.cpp [1]
Link: https://lore.kernel.org/r/20260203-inline-helpers-v2-0-beb8547a03c9@google.com [2]
Link: https://lore.kernel.org/r/aasPsbMEsX6iGUl8@google.com [3]
Reviewed-by: Rong Xu <xur@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Nicolas Schier <nsc@kernel.org>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260331-autofdo-v2-1-eb5c5964820d@google.com
[ Reworded for typos. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The chip name column in the /proc/interrupt output is 8 characters and
right aligned, which causes visual clutter due to the fixed length and the
alignment. Many interrupt chips, e.g. PCI/MSI[X] have way longer names.
Update the length when a chip is assigned to an interrupt and utilize this
information for the output. Align it left so all chip names start at the
begin of the column.
Update the GDB script as well and disentangle the header maze so it
actually works with all .config combinations.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Link: https://patch.msgid.link/20260517194932.085786035@kernel.org
Quite some architectures have four character wide acronyms for architecture
specific interrupts like IPI, NMI, etc.
The default precision of printing the Linux device interrupt numbers is
three, which causes quite some code to play games with adding or omitting
space after the acronym and the colon in order to keep the per CPU numbers
properly aligned.
Increase the default number precision to four in the core code and get rid
of the space games all over the place. At the same time align all
architecture specific descriptor texts left so that they show up in the
same column as the interrupt chip names, which makes the output more
uniform accross architectures. Fix up the GDB script to this new scheme as
well.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260517194931.839482411@kernel.org
x86 changed the interrupt statistics from a struct with individual members
to an counter array. It also provides a corresponding info array with the
strings for prefix and description and an indicator to skip the entry.
Update the already out of sync GDB script to use the counter and the info
array, which keeps the GDB script in sync automatically.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20260517194931.442613033@kernel.org
The Makefile version of rustc-option currently checks whether the option
exists for the host target instead of the target actually being compiled
for. It was done this way in commit 46e24a545c ("rust: kasan/kbuild:
fix missing flags on first build") to avoid a circular dependency on
target.json. However, because of this, rustc-option currently does not
function when cross-compiling from x86_64 to aarch64 if
CONFIG_SHADOW_CALL_STACK is enabled. This is because KBUILD_RUSTFLAGS
contains -Zfixed-x18 under this configuration. Since that flag does not
exist on the host target, rustc-option runs into a compilation failure
every time, leading to all flags being rejected as unsupported.
To fix this, update rustc-option to pass a --target parameter so that
the host target is not used. For targets using target.json, use a
built-in target that is as close as possible to the target created with
target.json to avoid the circular dependency on target.json.
One scenario where this causes a boot failure:
* Cross-compiled from x86_64 to aarch64.
* With CONFIG_SHADOW_CALL_STACK=y
* With CONFIG_KASAN_SW_TAGS=y
* With CONFIG_KASAN_INLINE=n
Then the resulting kernel image will fail to boot when it first calls
into Rust code with a crash along the lines of "Unable to handle kernel
paging request at virtual address 0ffffffc08541796". This is because the
call threshold is not specified, so rustc will inline kasan operations,
but the kasan shadow offset is not specified, which leads to the inlined
kasan instructions being incorrect.
Note that the -Zsanitizer=kernel-hwaddress parameter itself does not
lead to a rustc-option failure despite being aarch64-specific because
RUSTFLAGS_KASAN has not yet been added to KBUILD_RUSTFLAGS when
rustc-option is evaluated by the kasan Makefile.
Cc: stable@vger.kernel.org
Fixes: 46e24a545c ("rust: kasan/kbuild: fix missing flags on first build")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260507-rustc-option-cross-v2-1-2f650a49c2b5@google.com
[ Edited slightly:
- Reset variable to avoid using the environment.
- Use a simply expanded variable flavor for simplicity.
- Export variable so that behavior in sub-`make`s is consistent.
This matches other variables. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
It turns out that there are BPF use cases that rely on nesting RCU
Tasks Trace readers. These use cases are well-served by the old
rcu_read_lock_trace() and rcu_read_unlock_trace() functions that maintain
a nesting counter in the task_struct structure. But these use cases incur
a performance penalty when using the shiny new rcu_read_lock_tasks_trace()
and rcu_read_unlock_tasks_trace() functions, which nest in the same way
that SRCU does.
This means that rcu_read_lock_trace() and rcu_read_unlock_trace()
will be with us for some time. Therefore, remove the checkpatch.pl
deprecation.
Also, the rcu_read_lock_tasks_trace() and rcu_read_unlock_tasks_trace()
functions are intended for use only by BPF. Therefore, add them to
the list of functions that checkpatch complains about outside of BPF
(and of course, RCU).
Reported-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Pull Kbuild fixes from Nicolas Schier:
- modpost: prevent stack buffer overflow in do_input_entry() and
do_dmi_entry()
Defensively replace unbound sprintf() calls in file2alias to prevent
silent stack overflows and detect alias name overflows with proper
error message.
- kbuild: pacman-pkg: make "rc" releases adhere to pacman versioning
scheme
Enable smooth upgrades from "rc" releases w/ pacman packages.
* tag 'kbuild-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: pacman-pkg: make "rc" releases adhere to pacman versioning scheme
modpost: prevent stack buffer overflow in do_input_entry() and do_dmi_entry()
Pull misc fixes from Andrew Morton:
"14 hotfixes. 9 are for MM. 10 are cc:stable and the remainder are for
post-7.1 issues or aren't deemed suitable for backporting.
There's a two-patch MAINTAINERS series from Mike Rapoport which
updates us for the new KEXEC/KDUMP/crash/LUO/etc arrangements. And
another two-patch series from Muchun Song to fix a couple of
memory-hotplug issues. Otherwise singletons, please see the changelogs
for details"
* tag 'mm-hotfixes-stable-2026-05-18-21-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/memory: fix spurious warning when unmapping device-private/exclusive pages
mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()
drivers/base/memory: fix memory block reference leak in poison accounting
mm/memory_hotplug: fix memory block reference leak on remove
lib: kunit_iov_iter: fix test fail on powerpc
mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free
MAINTAINERS: add kexec@ list to LIVE UPDATE ENTRY
MAINTAINERS: add tree for KDUMP and KEXEC
selftests/mm: run_vmtests.sh: fix destructive tests invocation
scripts/gdb: slab: update field names of struct kmem_cache
scripts/gdb: mm: cast untyped symbols in x86_page_ops
mm/damon: fix damos_stat tracepoint format for sz_applied
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_page
Carlos Llamas
Ulises Mendez Martinez
Linus Torvalds
Ethan Nelson-Moore
Miguel Ojeda
James Lee
Zhou Yuhang
Siddharth Nayyar
Andrew Jones
Nathan Chancellor
Rong Xu
Masahiro Yamada
Alexandre Courbot
Yafang Shao
Philipp Hahn
Alice Ryhl
Thomas Gleixner
Paul E. McKenney