* Re: [PATCH v2] bootconfig: Apply early options from embedded config
From: Masami Hiramatsu @ 2026-04-01 13:48 UTC (permalink / raw)
To: Breno Leitao
Cc: Jonathan Corbet, Shuah Khan, linux-kernel, linux-trace-kernel,
linux-doc, oss, paulmck, rostedt, kernel-team
In-Reply-To: <acvjcCqIAeHyIiQN@gmail.com>
Hi Breno,
On Tue, 31 Mar 2026 08:27:59 -0700
Breno Leitao <leitao@debian.org> wrote:
> hello Masami,
>
> On Tue, Mar 31, 2026 at 12:58:27PM +0900, Masami Hiramatsu wrote:
>
> > > 3) Ensure that early bootconfig parameters don't overwrite the boot command
> > > line. For example, if the boot command line has foo=bar and bootconfig
> > > later has foo=baz, the command line value should take precedence.
> > > This prevents early boot code (in setup_arch()) from seeing a parameter
> > > value that will be changed later.
> >
> > OK, this also needs to be considered. Currently we just pass the bootconfig
> > parameters right before bootloader given parameters as "extra_command_line"
> > if "bootconfig" in cmdline or CONFIG_BOOT_CONFIG_FORCE=y.
> >
> > [boot_config(.kernel)]<command_line>[ -- [boot_config(.init)][init_command_line]]
> >
> > This is currently expected behavior. The bootconfig parameters are
> > expected to be overridden by command_line or command_line are appended.
>
> That's correct, and I have no intention of changing this behavior. Here's
> the current approach:
>
> 1) Early parameters from the bootloader are parsed first in setup_arch()
>
> 2) Subsequently, bootconfig_apply_early_params() is invoked. Any early
> parameter that was already parsed from the bootloader (in setup_arch())
> will be skipped at this stage.
Ah, I meant if we skip these parameters, we should not show it in the
command line via extra_command_line. This is still a minor issue at this
point. It should find early parameters in kernel.* parameters and do not
show it in extra_command_line, because those parameters are ignored.
So it is better to make a separated patch to fix that.
For example, if we pass
kernel.mem=1G
via bootconfig, it will be shown in the /proc/cmdline, but it is
not applied. This can confuse user.
>
> > If we change this for early params, we also should change the expected
> > output of /proc/cmdline too. I think we have 2 options;
> >
> > - As before, we expect the parameters provided by the boot configuration
> > to be processed first and then overridden later by the command line.
> >
> > Or,
> >
> > - ignore all parameters which is given from the command line, this also
> > updates existing setup_boot_config() (means xbc_snprint_cmdline() ).
> >
> > Anyway, this behavior change will also be a bit critical... We have
> > to announce it.
>
> As mentioned above, I don't anticipate any changes to existing behavior.
> Bootconfig parsing remains unchanged. The only modification is that
> bootconfig_apply_early_params() will skip any early config parameter
> that's already present in the bootloader command line.
Yes, but it is just different from existing one.
Suppose that if we have "early" and "normal" keys in the kernel, those
are handled by early_param() and __setup() respectively.
If we use bootconfig, like
kernel {
early = bconf_val
normal = bconf_val
}
And passes "early=foo normal=bar" via cmdline.
In this case, the /proc/cmdline eventually has
"early=bconf_val normal=bconf_val early=foo normal=bar"
And the "normal" callback called with "bconf_val" and "bar" twice.
However, "early" callback will be called with "foo" only once.
That can confuse users too.
I believe it's important for the system to behave in a way that is
as close as possible to the user's mind model.
Because the behavior is inconsistent when multiple parameters with
the same name are specified on the kernel command line, it is
necessary to ensure that users can later look at it and infer what
happened.
I mean, if a parameter is skipped, it should not be printed at
/proc/cmdline, because it can mislead user (and maybe bug reporter)
when a problem happens.
>
> > > +Note that embedded bootconfig is parsed after ``setup_arch()``, so
> > > +early options that are consumed during architecture initialization
> > > +(e.g., ``mem=``, ``memmap=``, ``earlycon``, ``noapic``, ``nolapic``,
> > > +``acpi=``, ``numa=``, ``iommu=``) may not take effect from bootconfig.
> > > +
> >
> > This is easy to explain, but it's quite troublesome for users to
> > determine which parameters are unavailable.
>
> Agreed. This turned out to be significantly more complex than I
> initially anticipated.
Yeah, that's complicated.
>
> I'm uncertain whether we can accomplish this without examining every
> early_parameter() implementation in depth.
Agreed. My proposal is something like a divide and conquer approach.
Since these are implemented architecture by architecture, you need to
check the implementation for each architecture, and I think it's best
to implement them one by one using Kconfig.
>
> > Currently we can identify
> > it by `git grep early_param -- arch/${ARCH}`. But it is setup in
> > setup_arch() we need to track the source code. (Or ask AI :))
>
> The challenge extends beyond that. There are numerous early_parameter()
> definitions scattered throughout the kernel that may or may not be
> utilized by setup_arch().
>
> For example, consider `early_param("mitigations", ..)` in
> ./kernel/cpu.c. This modifies the cpu_mitigations global variable, which
> is referenced in various locations across different architectures.
>
> It's worth noting that we have over 300 early_parameter() instances in
> the kernel.
>
> Given this, analyzing all these early parameters and examining each one
> individually represents a substantial amount of work.
Yes, that may require a substantial amount of work. But to improve
the kernel framework around the parameter handling, eventually we
need to examine each early parameter.
>
> Are there alternative approaches? At this point, I'm leaning toward
> breaking bootconfig's dependency on memblock, allowing us to invoke it
> before setup_arch(). Is this the only practical solution available?!
Basically, the memblock dependency comes from allocating copy of data.
Only for the embedded bootconfig, we can just pass copy memory block
to the xbc_init(). Something like;
xbc_init() {
xbc_data = memblock_alloc();
memcpy(xbc_data, data);
__xbc_init(xbc_data);
}
embedded_xbc_init() {
__xbc_init(embedded_bootconfig_data);
}
Afterwards, we can pass mixture of embedded bootcofnigt and initrd
bootconfig data to parser again.
(But in this case, we must be careful not to override the early
parameters that we have already applied.)
Thank you,
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: [PATCH 06/33] rust: kbuild: remove skipping of `-Wrustdoc::unescaped_backticks`
From: Gary Guo @ 2026-04-01 13:44 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-7-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> Back in Rust 1.82.0, I cleaned the `rustdoc::unescaped_backticks` lint in
> upstream Rust and added tests so that hopefully it would not regress [1].
>
> Thus we can remove it from our side given the Rust minimum version bump.
>
> Link: https://github.com/rust-lang/rust/pull/128307 [1]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> rust/Makefile | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
^ permalink raw reply
* Re: [PATCH 05/33] rust: remove `RUSTC_HAS_COERCE_POINTEE` and simplify code
From: Gary Guo @ 2026-04-01 13:44 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-6-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> With the Rust version bump in place, the `RUSTC_HAS_COERCE_POINTEE`
> Kconfig (automatic) option is always true.
>
> Thus remove the option and simplify the code.
>
> In particular, this includes removing our use of the predecessor unstable
> features we used with Rust < 1.84.0 (`coerce_unsized`, `dispatch_from_dyn`
> and `unsize`).
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> init/Kconfig | 3 ---
> rust/kernel/alloc/kbox.rs | 29 ++---------------------------
> rust/kernel/lib.rs | 8 +-------
> rust/kernel/list/arc.rs | 22 +---------------------
> rust/kernel/sync/arc.rs | 21 ++-------------------
> 5 files changed, 6 insertions(+), 77 deletions(-)
^ permalink raw reply
* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Miguel Ojeda @ 2026-04-01 13:31 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHUQRB9ZL54.VQZ7OUZNSYDS@garyguo.net>
On Wed, Apr 1, 2026 at 3:28 PM Gary Guo <gary@garyguo.net> wrote:
>
> This diff fails to apply on linux-next, due to conflict with ece7e57afd51
> ("docs: changes.rst and ver_linux: sort the lists").
Yeah, sorry, I should have added `--base-commit` -- it is `rust-next`,
i.e. 3a2486cc1da5 ("kbuild: rust: provide an option to inline C
helpers into Rust").
There will be other conflicts too, e.g. in the list of features in
`scripts/Makefile.build`.
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Gary Guo @ 2026-04-01 13:28 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-2-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
>
> Debian Trixie's release happened on 2025-08-09 [4], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
>
> Thus bump the minimum to the new version.
>
> Then, in later commits, clean up most of the workarounds and other bits
> that this upgrade of the minimum allows us.
>
> pin-init was left as-is since the patches come from upstream. And the
> vendored crates are unmodified, since we do not want to change those.
>
> Note that the minimum LLVM major version for Rust 1.85.0 is LLVM 18 (the
> Rust upstream binaries use LLVM 19.1.7), thus e.g. `RUSTC_LLVM_VERSION`
> tests can also be updated, but there are no suitable ones to simplify.
>
> Ubuntu 25.10 also has a recent enough Rust toolchain [5], and they also
> provide versioned packages with a Rust 1.85.1 toolchain even back to
> Ubuntu 22.04 LTS [6].
>
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://www.debian.org/releases/trixie/ [4]
> Link: https://packages.ubuntu.com/search?suite=all&searchon=names&keywords=rustc [5]
> Link: https://launchpad.net/ubuntu/+source/rustc-1.85 [6]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> Documentation/process/changes.rst | 2 +-
> scripts/min-tool-version.sh | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> index 6b373e193548..474594bd4831 100644
> --- a/Documentation/process/changes.rst
> +++ b/Documentation/process/changes.rst
This diff fails to apply on linux-next, due to conflict with ece7e57afd51
("docs: changes.rst and ver_linux: sort the lists").
Best,
Gary
> @@ -31,7 +31,7 @@ you probably needn't concern yourself with pcmciautils.
> ====================== =============== ========================================
> GNU C 8.1 gcc --version
> Clang/LLVM (optional) 15.0.0 clang --version
> -Rust (optional) 1.78.0 rustc --version
> +Rust (optional) 1.85.0 rustc --version
> bindgen (optional) 0.65.1 bindgen --version
> GNU make 4.0 make --version
> bash 4.2 bash --version
> diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
> index 99b5575c1ef7..a270ec761f64 100755
> --- a/scripts/min-tool-version.sh
> +++ b/scripts/min-tool-version.sh
> @@ -31,7 +31,7 @@ llvm)
> fi
> ;;
> rustc)
> - echo 1.78.0
> + echo 1.85.0
> ;;
> bindgen)
> echo 0.65.1
^ permalink raw reply
* Re: [PATCH 04/33] rust: remove `RUSTC_HAS_SLICE_AS_FLATTENED` and simplify code
From: Gary Guo @ 2026-04-01 13:18 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-5-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> With the Rust version bump in place, the `RUSTC_HAS_SLICE_AS_FLATTENED`
> Kconfig (automatic) option is always true.
>
> Thus remove the option and simplify the code.
>
> In particular, this includes removing the `slice` module which contained
> the temporary slice helpers, i.e. the `AsFlattened` extension trait and
> its `impl`s.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> init/Kconfig | 3 ---
> rust/kernel/lib.rs | 1 -
> rust/kernel/prelude.rs | 3 ---
> rust/kernel/slice.rs | 49 ------------------------------------------
> 4 files changed, 56 deletions(-)
> delete mode 100644 rust/kernel/slice.rs
^ permalink raw reply
* Re: [PATCH 03/33] rust: simplify `RUSTC_VERSION` Kconfig conditions
From: Gary Guo @ 2026-04-01 13:18 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-4-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> With the Rust version bump in place, several Kconfig conditions based on
> `RUSTC_VERSION` are always true.
>
> Thus simplify them.
>
> The minimum supported major LLVM version by our new Rust minimum version
> is now LLVM 18, instead of LLVM 16. However, there are no possible
> cleanups for `RUSTC_LLVM_VERSION`.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> arch/Kconfig | 3 +--
> arch/arm64/Kconfig | 8 --------
> arch/riscv/Kconfig | 3 ---
> init/Kconfig | 2 --
> 4 files changed, 1 insertion(+), 15 deletions(-)
^ permalink raw reply
* Re: [PATCH v9 2/9] lib: vsprintf: export simple_strntoull() in a safe prototype
From: Rodrigo Alencar @ 2026-04-01 13:16 UTC (permalink / raw)
To: Petr Mladek, Rodrigo Alencar
Cc: Andy Shevchenko, rodrigo.alencar, linux-kernel, linux-iio,
devicetree, linux-doc, Jonathan Cameron, David Lechner,
Andy Shevchenko, Lars-Peter Clausen, Michael Hennerich,
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Jonathan Corbet,
Andrew Morton, Steven Rostedt, Rasmus Villemoes,
Sergey Senozhatsky, Shuah Khan
In-Reply-To: <ac0N89sNYcKAJkAP@pathway.suse.cz>
On 26/04/01 02:22PM, Petr Mladek wrote:
> On Mon 2026-03-30 13:49:48, Rodrigo Alencar wrote:
> > On 26/03/27 03:17PM, Rodrigo Alencar wrote:
> > > On 26/03/27 12:21PM, Andy Shevchenko wrote:
> > > > On Fri, Mar 27, 2026 at 10:11:56AM +0000, Rodrigo Alencar wrote:
> > > > > On 26/03/27 11:17AM, Andy Shevchenko wrote:
> > > > > > On Fri, Mar 27, 2026 at 09:45:17AM +0100, Petr Mladek wrote:
> > > > > > > On Fri 2026-03-20 16:27:27, Rodrigo Alencar via B4 Relay wrote:
> >
> > ...
> >
> > > > > > Maybe we want to have kstrtof32() and kstrtof64() for these two cases?
> > > > > >
> > > > > > With that we will always consider the fraction part as 32- or 64-bit,
> > > > > > imply floor() on the fraction for the sake of simplicity and require
> > > > > > it to be NUL-terminated with possible trailing '\n'.
> > > > >
> > > > > I think this is a good idea, but calling it float or fixed point itself
> > > > > is a bit confusing as float often refers to the IEEE 754 standard and
> > > > > fixed point types is often expressed in Q-format.
> > > >
> > > > Yeah... I am lack of better naming.
> > >
> > > decimals is the name, but they are often represented as:
> > >
> > > DECIMAL = INT * 10^X + FRAC
> > >
> > > in a single 64-bit number, which would be fine for my end use case.
> > > However IIO decimal fixed point parsing is out there for quite some time a
> > > lot of drivers use that. The interface often relies on breaking parsed values
> > > into an integer array (for standard attributes int val and int val2 are expected).
> >
> > Thinking about this again and in IIO drivers we end up doing something like:
> >
> > val64 = (u64)val * MICRO + val2;
> >
> > so that drivers often work with scaled versions of the decimal value.
> > then, would it make sense to have a function that already outputs such value?
> > That would allow to have more freedom over the 64-bit split between integer
> > and fractional parts.
> > As a draft:
>
> My understanding is that you want to allow parsing frequencies
> in the range from microHz to GHz.
Correct, the ABI requires the values in Hz, and I would like to support
micro Hz resolution, so that 10 GHz can be represensted as:
10000000000.000000
> So, you might want to support input in simple float numbers
> with some precision, for example, 1.2GHz, 0.345Hz, ...
>
> By simple, I mean that there is no x10^3 or so.
>
> > static int _kstrtodec64(const char *s, unsigned int scale, u64 *res)
>
> I would personally change this to something like:
>
> static int _unit_float_ktstrtodec64(const char *s, unsigned int precision, u64 *res, char **unit)
I don't really need "unit" for my specific use case, IIUC this pattern is not
something to be handled by kstrto*(), because those function should requires NUL
termination. I am not sure why is that, but I like the idea of returning a
const char* pointer to the end of the conversion (that was the whole point of
having something like kstrntoull())
> It would allow to read float number in the the format XXXX.YYYYunit,
> for example 1.2Ghz
>
> , where:
>
> + _unit_ means that it might set @unit pointer which point to the unit
> string right after the number part.
as mentioned, the units is defined in the ABI, so this part is not really needed.
> + _float_ means that it will be able to read float numbers
its a decimal fixed precision, decimal point should not float.
>
> + @precisions parameter defines the number of digits accepted
> after the radix point. It is also used as multiplier for scaling
> the output number.
precision != scale, for this case we have a fixed precision of 64-bits.
while scale is passed as parameter.
Reference:
https://www.ibm.com/docs/ro/informix-servers/12.10.0?topic=types-decimalps-data
>
> + @res is pointer to the read number multiplied by the given
> @precision
>
> + @unit will be set to string after the number
>
> For example:
>
> + s="1.2GHz", precision=3 will result in *res=1200, *unit="GHz"
> + s="0.0100004", precision=3 will result in *res=10, *unit=""
> + s=1.234567GHz, precision=3 will result in *res=1235, *unit="GHz"
>
> Note that the result is rounded in the last example.
>
> The function might be used like simple_strtoull() in memparse(),
> see lib/cmdline.c. Which is able to read the given size in B
> and handle various units like kB, GB, ...
As dicussed above, scaling the value based on the units is not my use case.
>
> > {
> > u64 _res = 0, _frac = 0;
> > unsigned int rv;
> >
> > if (*s != '.') {
> > rv = _parse_integer(s, 10, &_res);
> > if (rv & KSTRTOX_OVERFLOW)
> > return -ERANGE;
> > if (rv == 0)
> > return -EINVAL;
> > s += rv;
> > }
> >
> > if (*s == '.') {
> > s++;
> > rv = _parse_integer_limit(s, 10, &_frac, scale);
> > if (rv & KSTRTOX_OVERFLOW)
> > return -ERANGE;
> > if (rv == 0)
> > return -EINVAL;
> > s += rv;
> > if (rv < scale)
> > _frac *= int_pow(10, scale - rv);
> > while (isdigit(*s)) /* truncate */
> > s++;
>
> We might/should use the first digit to round the _frac.
flooring should not be a problem if it is documented like that.
I suppose we cannot afford to carry over all roundings from
subsequent digits. If so, we would be parsing it all and use
div64 which I would like avoid.
> > }
> >
> > if (*s == '\n')
> > s++;
> > if (*s)
> > return -EINVAL;
>
> I would omit this. Instead I would set @unit pointer so that the
> caller might handle units defined after the number.
I understand that this is the whole point of creating a kstrto*()
function.
> > if (check_mul_overflow(_res, int_pow(10, scale), &_res) ||
> > check_add_overflow(_res, _frac, &_res))
> > return -ERANGE;
> >
> > *res = _res;
> > return 0;
> > }
>
> Otherwise, this approach looks sensible to me. IMHO, some generic
> API for reading numbers with misc units should be usable in more
> situations. And it would make the kernel interface more user
> friendly.
>
> Of course, we must not over-engineer it. But the above does not
> look much more complex than we already have.
I really appreciate your time looking into this, thanks.
--
Kind regards,
Rodrigo Alencar
^ permalink raw reply
* Re: [PATCH 02/33] rust: bump Clippy's MSRV and clean `incompatible_msrv` allows
From: Gary Guo @ 2026-04-01 13:15 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-3-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> Following the Rust compiler bump, we can now update Clippy's MSRV we
> set in the configuration, which will improve the diagnostics it generates.
>
> Thus do so and clean a few of the `allow`s that are not needed anymore.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> .clippy.toml | 2 +-
> drivers/gpu/nova-core/gsp/cmdq.rs | 6 +-----
> rust/kernel/ptr.rs | 1 -
> rust/kernel/transmute.rs | 2 --
> 4 files changed, 2 insertions(+), 9 deletions(-)
^ permalink raw reply
* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Gary Guo @ 2026-04-01 13:11 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-2-ojeda@kernel.org>
On Wed Apr 1, 2026 at 12:45 PM BST, Miguel Ojeda wrote:
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
>
> Debian Trixie's release happened on 2025-08-09 [4], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
>
> Thus bump the minimum to the new version.
>
> Then, in later commits, clean up most of the workarounds and other bits
> that this upgrade of the minimum allows us.
>
> pin-init was left as-is since the patches come from upstream. And the
> vendored crates are unmodified, since we do not want to change those.
>
> Note that the minimum LLVM major version for Rust 1.85.0 is LLVM 18 (the
> Rust upstream binaries use LLVM 19.1.7), thus e.g. `RUSTC_LLVM_VERSION`
> tests can also be updated, but there are no suitable ones to simplify.
>
> Ubuntu 25.10 also has a recent enough Rust toolchain [5], and they also
> provide versioned packages with a Rust 1.85.1 toolchain even back to
> Ubuntu 22.04 LTS [6].
>
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://www.debian.org/releases/trixie/ [4]
> Link: https://packages.ubuntu.com/search?suite=all&searchon=names&keywords=rustc [5]
> Link: https://launchpad.net/ubuntu/+source/rustc-1.85 [6]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Gary Guo <gary@garyguo.net>
> ---
> Documentation/process/changes.rst | 2 +-
> scripts/min-tool-version.sh | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
^ permalink raw reply
* Re: [PATCH v2 0/2] drm: Rename drm_atomic_state
From: Jani Nikula @ 2026-04-01 12:41 UTC (permalink / raw)
To: Maxime Ripard, David Airlie, Simona Vetter, Maarten Lankhorst,
Thomas Zimmermann, Jonathan Corbet
Cc: Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin, Alex Deucher,
Christian König, Rob Clark, Dmitry Baryshkov, Andrzej Hajda,
Neil Armstrong, Robert Foss, Dave Stevenson, Laurent Pinchart,
dri-devel, linux-doc, Maxime Ripard, Simona Vetter
In-Reply-To: <20260331-drm-drm-atomic-update-v2-0-7e8fe6ddcd32@kernel.org>
On Tue, 31 Mar 2026, Maxime Ripard <mripard@kernel.org> wrote:
> We've been discussing for a long time about renaming drm_atomic_state
> to a better suited name, since the current one is a source of confusion
> and bugs.
>
> To minimize the impact, this should probably go through drm-next
> directly.
>
> Let me know what you think,
I don't really have strong opinions on this one, except I agree this
should go directly through drm-next before the merge window so everyone
can backmerge it. Otherwise it's going to be a conflicts galore.
IMO drivers can do the variable renames afterwards at leisure.
For the i915 parts,
Acked-by: Jani Nikula <jani.nikula@intel.com>
--
Jani Nikula, Intel
^ permalink raw reply
* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Miguel Ojeda @ 2026-04-01 12:38 UTC (permalink / raw)
To: Alice Ryhl, Fabian Grünbichler, Fabian Grünbichler,
Fabian Grünbichler, NoisyCoil
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <ac0Ol1PaRTWNK6O9@google.com>
On Wed, Apr 1, 2026 at 2:25 PM Alice Ryhl <aliceryhl@google.com> wrote:
>
> Debian really *should* pick up 1.85.1. It contains bugfixes serious
> enough that the Rust team decided it was reasonble to release a point
> release.
I asked them about their policy yesterday here:
https://lore.kernel.org/rust-for-linux/20260331190053.482607-1-ojeda@kernel.org/
Perhaps they just prefer to apply patches on top.
The issue linked above is the only one I noticed so far, and it is
quite specific.
Anyway, it is up to them.
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH 21/33] gpu: nova-core: bindings: remove unneeded `cfg_attr`
From: Danilo Krummrich @ 2026-04-01 12:29 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Andreas Hindborg,
Catalin Marinas, Will Deacon, Paul Walmsley, Palmer Dabbelt,
Albert Ou, Alexandre Courbot, David Airlie, Simona Vetter,
Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-22-ojeda@kernel.org>
On Wed Apr 1, 2026 at 1:45 PM CEST, Miguel Ojeda wrote:
> These were likely copied from the `bindings` and `uapi` crates, but are
> unneeded since there are no `cfg(test)`s in the bindings.
>
> In addition, the issue that triggered the addition in those crates
> originally is also fixed in `bindgen` (please see the previous commit).
>
> Thus remove them.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
^ permalink raw reply
* Re: [PATCH 11/33] rust: alloc: simplify with `NonNull::add()` now that it is stable
From: Danilo Krummrich @ 2026-04-01 12:28 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Andreas Hindborg,
Catalin Marinas, Will Deacon, Paul Walmsley, Palmer Dabbelt,
Albert Ou, Alexandre Courbot, David Airlie, Simona Vetter,
Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-12-ojeda@kernel.org>
On Wed Apr 1, 2026 at 1:45 PM CEST, Miguel Ojeda wrote:
> Currently we need to go through raw pointers and then re-create the
> `NonNull` from the result of offsetting the raw pointer.
>
> Thus, now that we bump the Rust minimum version, simplify using
> `NonNull::add()` and clean the TODO note.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
^ permalink raw reply
* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Danilo Krummrich @ 2026-04-01 12:28 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Andreas Hindborg,
Catalin Marinas, Will Deacon, Paul Walmsley, Palmer Dabbelt,
Albert Ou, Alexandre Courbot, David Airlie, Simona Vetter,
Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-2-ojeda@kernel.org>
On Wed Apr 1, 2026 at 1:45 PM CEST, Miguel Ojeda wrote:
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
>
> Debian Trixie's release happened on 2025-08-09 [4], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
>
> Thus bump the minimum to the new version.
>
> Then, in later commits, clean up most of the workarounds and other bits
> that this upgrade of the minimum allows us.
>
> pin-init was left as-is since the patches come from upstream. And the
> vendored crates are unmodified, since we do not want to change those.
>
> Note that the minimum LLVM major version for Rust 1.85.0 is LLVM 18 (the
> Rust upstream binaries use LLVM 19.1.7), thus e.g. `RUSTC_LLVM_VERSION`
> tests can also be updated, but there are no suitable ones to simplify.
>
> Ubuntu 25.10 also has a recent enough Rust toolchain [5], and they also
> provide versioned packages with a Rust 1.85.1 toolchain even back to
> Ubuntu 22.04 LTS [6].
>
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://www.debian.org/releases/trixie/ [4]
> Link: https://packages.ubuntu.com/search?suite=all&searchon=names&keywords=rustc [5]
> Link: https://launchpad.net/ubuntu/+source/rustc-1.85 [6]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
^ permalink raw reply
* Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
From: Alice Ryhl @ 2026-04-01 12:24 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-2-ojeda@kernel.org>
On Wed, Apr 01, 2026 at 01:45:08PM +0200, Miguel Ojeda wrote:
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
Debian really *should* pick up 1.85.1. It contains bugfixes serious
enough that the Rust team decided it was reasonble to release a point
release.
> Debian Trixie's release happened on 2025-08-09 [4], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
>
> Thus bump the minimum to the new version.
>
> Then, in later commits, clean up most of the workarounds and other bits
> that this upgrade of the minimum allows us.
>
> pin-init was left as-is since the patches come from upstream. And the
> vendored crates are unmodified, since we do not want to change those.
>
> Note that the minimum LLVM major version for Rust 1.85.0 is LLVM 18 (the
> Rust upstream binaries use LLVM 19.1.7), thus e.g. `RUSTC_LLVM_VERSION`
> tests can also be updated, but there are no suitable ones to simplify.
>
> Ubuntu 25.10 also has a recent enough Rust toolchain [5], and they also
> provide versioned packages with a Rust 1.85.1 toolchain even back to
> Ubuntu 22.04 LTS [6].
>
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://www.debian.org/releases/trixie/ [4]
> Link: https://packages.ubuntu.com/search?suite=all&searchon=names&keywords=rustc [5]
> Link: https://launchpad.net/ubuntu/+source/rustc-1.85 [6]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply
* Re: [PATCH v9 2/9] lib: vsprintf: export simple_strntoull() in a safe prototype
From: Petr Mladek @ 2026-04-01 12:22 UTC (permalink / raw)
To: Rodrigo Alencar
Cc: Andy Shevchenko, rodrigo.alencar, linux-kernel, linux-iio,
devicetree, linux-doc, Jonathan Cameron, David Lechner,
Andy Shevchenko, Lars-Peter Clausen, Michael Hennerich,
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Jonathan Corbet,
Andrew Morton, Steven Rostedt, Rasmus Villemoes,
Sergey Senozhatsky, Shuah Khan
In-Reply-To: <qnb3ozrhrq5n4zkh2luitkpwr5oj4omgcuo5vnvy2gatdfdqlg@cgsgux7etcql>
On Mon 2026-03-30 13:49:48, Rodrigo Alencar wrote:
> On 26/03/27 03:17PM, Rodrigo Alencar wrote:
> > On 26/03/27 12:21PM, Andy Shevchenko wrote:
> > > On Fri, Mar 27, 2026 at 10:11:56AM +0000, Rodrigo Alencar wrote:
> > > > On 26/03/27 11:17AM, Andy Shevchenko wrote:
> > > > > On Fri, Mar 27, 2026 at 09:45:17AM +0100, Petr Mladek wrote:
> > > > > > On Fri 2026-03-20 16:27:27, Rodrigo Alencar via B4 Relay wrote:
>
> ...
>
> > > > > Maybe we want to have kstrtof32() and kstrtof64() for these two cases?
> > > > >
> > > > > With that we will always consider the fraction part as 32- or 64-bit,
> > > > > imply floor() on the fraction for the sake of simplicity and require
> > > > > it to be NUL-terminated with possible trailing '\n'.
> > > >
> > > > I think this is a good idea, but calling it float or fixed point itself
> > > > is a bit confusing as float often refers to the IEEE 754 standard and
> > > > fixed point types is often expressed in Q-format.
> > >
> > > Yeah... I am lack of better naming.
> >
> > decimals is the name, but they are often represented as:
> >
> > DECIMAL = INT * 10^X + FRAC
> >
> > in a single 64-bit number, which would be fine for my end use case.
> > However IIO decimal fixed point parsing is out there for quite some time a
> > lot of drivers use that. The interface often relies on breaking parsed values
> > into an integer array (for standard attributes int val and int val2 are expected).
>
> Thinking about this again and in IIO drivers we end up doing something like:
>
> val64 = (u64)val * MICRO + val2;
>
> so that drivers often work with scaled versions of the decimal value.
> then, would it make sense to have a function that already outputs such value?
> That would allow to have more freedom over the 64-bit split between integer
> and fractional parts.
> As a draft:
My understanding is that you want to allow parsing frequencies
in the range from microHz to GHz.
So, you might want to support input in simple float numbers
with some precision, for example, 1.2GHz, 0.345Hz, ...
By simple, I mean that there is no x10^3 or so.
> static int _kstrtodec64(const char *s, unsigned int scale, u64 *res)
I would personally change this to something like:
static int _unit_float_ktstrtodec64(const char *s, unsigned int precision, u64 *res, char **unit)
It would allow to read float number in the the format XXXX.YYYYunit,
for example 1.2Ghz
, where:
+ _unit_ means that it might set @unit pointer which point to the unit
string right after the number part.
+ _float_ means that it will be able to read float numbers
+ @precisions parameter defines the number of digits accepted
after the radix point. It is also used as multiplier for scaling
the output number.
+ @res is pointer to the read number multiplied by the given
@precision
+ @unit will be set to string after the number
For example:
+ s="1.2GHz", precision=3 will result in *res=1200, *unit="GHz"
+ s="0.0100004", precision=3 will result in *res=10, *unit=""
+ s=1.234567GHz, precision=3 will result in *res=1235, *unit="GHz"
Note that the result is rounded in the last example.
The function might be used like simple_strtoull() in memparse(),
see lib/cmdline.c. Which is able to read the given size in B
and handle various units like kB, GB, ...
> {
> u64 _res = 0, _frac = 0;
> unsigned int rv;
>
> if (*s != '.') {
> rv = _parse_integer(s, 10, &_res);
> if (rv & KSTRTOX_OVERFLOW)
> return -ERANGE;
> if (rv == 0)
> return -EINVAL;
> s += rv;
> }
>
> if (*s == '.') {
> s++;
> rv = _parse_integer_limit(s, 10, &_frac, scale);
> if (rv & KSTRTOX_OVERFLOW)
> return -ERANGE;
> if (rv == 0)
> return -EINVAL;
> s += rv;
> if (rv < scale)
> _frac *= int_pow(10, scale - rv);
> while (isdigit(*s)) /* truncate */
> s++;
We might/should use the first digit to round the _frac.
> }
>
> if (*s == '\n')
> s++;
> if (*s)
> return -EINVAL;
I would omit this. Instead I would set @unit pointer so that the
caller might handle units defined after the number.
> if (check_mul_overflow(_res, int_pow(10, scale), &_res) ||
> check_add_overflow(_res, _frac, &_res))
> return -ERANGE;
>
> *res = _res;
> return 0;
> }
Otherwise, this approach looks sensible to me. IMHO, some generic
API for reading numbers with misc units should be usable in more
situations. And it would make the kernel interface more user
friendly.
Of course, we must not over-engineer it. But the above does not
look much more complex than we already have.
Best Regards,
Petr
PS: I am sorry if I used some mathematical terms a wrong way.
I am not a native speaker. And it is a long time since
I worked with float numbers.
^ permalink raw reply
* [PATCH 33/33] rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
The Clippy `precedence` lint was extended in Rust 1.85.0 to include
bitmasking and shift operations [1]. However, because it generated
many hits, in Rust 1.86.0 it was split into a new `precedence_bits`
lint which is not enabled by default [2].
In other words, only Rust 1.85 has a different behavior. For instance,
it reports:
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/fb/hal/ga100.rs:16:5
|
16 | / u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR::read(bar).adr_39_08()) << FLUSH_SYSMEM_ADDR_SHIFT
17 | | | u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR_HI::read(bar).adr_63_40())
18 | | << FLUSH_SYSMEM_ADDR_SHIFT_HI
| |_________________________________________^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
= note: `-W clippy::precedence` implied by `-W clippy::all`
= help: to override `-W clippy::all` add `#[allow(clippy::precedence)]`
help: consider parenthesizing your expression
|
16 ~ (u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR::read(bar).adr_39_08()) << FLUSH_SYSMEM_ADDR_SHIFT) | (u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR_HI::read(bar).adr_63_40())
17 + << FLUSH_SYSMEM_ADDR_SHIFT_HI)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
513 | | | u32::from(data[27]) << 8
| |______________________________________________^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
help: consider parenthesizing your expression
|
511 ~ u32::from(data[29]) << 24
512 + | u32::from(data[28]) << 16 | (u32::from(data[27]) << 8)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
| |_______________________________________________^ help: consider parenthesizing your expression: `(u32::from(data[29]) << 24) | (u32::from(data[28]) << 16)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
While so far we try our best to keep all versions Clippy-clean, the
minimum (which is now Rust 1.85.0 after the bump) and the latest stable
are the most important ones; and this may be considered "false positives"
with respect to the behavior in other versions.
Thus allow this lint for this version using the per-version flags
mechanism introduced in the previous commit.
Link: https://github.com/rust-lang/rust-clippy/issues/14097 [1]
Link: https://github.com/rust-lang/rust-clippy/pull/14115 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 20c8179d96ee..a0d6ed050c8a 100644
--- a/Makefile
+++ b/Makefile
@@ -836,7 +836,8 @@ export WARN_ON_UNUSED_TRACEPOINTS
# Per-version Rust flags. These are like `rust_common_flags`, but may
# depend on the Rust compiler version (e.g. using `rustc-min-version`).
-rust_common_flags_per_version :=
+rust_common_flags_per_version := \
+ $(if $(call rustc-min-version,108600),,-Aclippy::precedence)
rust_common_flags += $(rust_common_flags_per_version)
KBUILD_HOSTRUSTFLAGS += $(rust_common_flags_per_version)
--
2.53.0
^ permalink raw reply related
* [PATCH 32/33] rust: kbuild: support global per-version flags
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
Sometimes it is useful to gate global Rust flags per compiler version.
For instance, we may want to disable a lint that has false positives in
a single version [1].
We already had helpers like `rustc-min-version` for that, which we use
elsewhere, but we cannot currently use them for `rust_common_flags`,
which contains the global flags for all Rust code (kernel and host),
because `rustc-min-version` depends on `CONFIG_RUSTC_VERSION`, which
does not exist when `rust_common_flags` is defined.
Thus, to support that, introduce `rust_common_flags_per_version`,
defined after the `include/config/auto.conf` inclusion (where
`CONFIG_RUSTC_VERSION` becomes available), and append it to
`rust_common_flags`, `KBUILD_HOSTRUSTFLAGS` and `KBUILD_RUSTFLAGS`.
An alternative is moving all those three down, but that would mean
separating them from the other `KBUILD_*` variables.
Link: https://lore.kernel.org/rust-for-linux/CANiq72mWdFU11GcCZRchzhy0Gi1QZShvZtyRkHV2O+WA2uTdVQ@mail.gmail.com/ [1]
Link: https://patch.msgid.link/20260307170929.153892-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Makefile | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/Makefile b/Makefile
index 1a219bf1c771..20c8179d96ee 100644
--- a/Makefile
+++ b/Makefile
@@ -834,6 +834,14 @@ endif # CONFIG_TRACEPOINTS
export WARN_ON_UNUSED_TRACEPOINTS
+# Per-version Rust flags. These are like `rust_common_flags`, but may
+# depend on the Rust compiler version (e.g. using `rustc-min-version`).
+rust_common_flags_per_version :=
+
+rust_common_flags += $(rust_common_flags_per_version)
+KBUILD_HOSTRUSTFLAGS += $(rust_common_flags_per_version)
+KBUILD_RUSTFLAGS += $(rust_common_flags_per_version)
+
include $(srctree)/arch/$(SRCARCH)/Makefile
ifdef need-config
--
2.53.0
^ permalink raw reply related
* [PATCH 31/33] rust: declare cfi_encoding for lru_status
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
From: Alice Ryhl <aliceryhl@google.com>
By default bindgen will convert 'enum lru_status' into a typedef for an
integer. For the most part, an integer of the same size as the enum
results in the correct ABI, but in the specific case of CFI, that is not
the case. The CFI encoding is supposed to be the same as a struct called
'lru_status' rather than the name of the underlying native integer type.
To fix this, tell bindgen to generate a newtype and set the CFI type
explicitly. Note that we need to set the CFI attribute explicitly as
bindgen is using repr(transparent), which is otherwise identical to the
inner type for ABI purposes.
This allows us to remove the page range helper C function in Binder
without risking a CFI failure when list_lru_walk calls the provided
function pointer.
The --with-attribute-custom-enum argument requires bindgen v0.71 or
greater.
[ In particular, the feature was added in 0.71.0 [1][2].
In addition, `feature(cfi_encoding)` has been available since
Rust 1.71.0 [3].
Link: https://github.com/rust-lang/rust-bindgen/issues/2520 [1]
Link: https://github.com/rust-lang/rust-bindgen/pull/2866 [2]
Link: https://github.com/rust-lang/rust/pull/105452 [3]
- Miguel ]
My testing procedure was to add this to the android17-6.18 branch and
verify that rust_shrink_free_page is successfully called without crash,
and verify that it does in fact crash when the cfi_encoding is set to
other values. Note that I couldn't test this on android16-6.12 as that
branch uses a bindgen version that is too old.
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260223-cfi-lru-status-v2-1-89c6448a63a4@google.com
[ Rebased on top of the minimum Rust version bump series which provide
the required `bindgen` version. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
drivers/android/binder/Makefile | 3 +--
drivers/android/binder/page_range.rs | 6 +++---
drivers/android/binder/page_range_helper.c | 24 ----------------------
drivers/android/binder/page_range_helper.h | 15 --------------
rust/bindgen_parameters | 4 ++++
rust/bindings/bindings_helper.h | 1 -
rust/bindings/lib.rs | 1 +
rust/uapi/lib.rs | 1 +
8 files changed, 10 insertions(+), 45 deletions(-)
delete mode 100644 drivers/android/binder/page_range_helper.c
delete mode 100644 drivers/android/binder/page_range_helper.h
diff --git a/drivers/android/binder/Makefile b/drivers/android/binder/Makefile
index 09eabb527fa0..7e0cd9782a8b 100644
--- a/drivers/android/binder/Makefile
+++ b/drivers/android/binder/Makefile
@@ -5,5 +5,4 @@ obj-$(CONFIG_ANDROID_BINDER_IPC_RUST) += rust_binder.o
rust_binder-y := \
rust_binder_main.o \
rust_binderfs.o \
- rust_binder_events.o \
- page_range_helper.o
+ rust_binder_events.o
diff --git a/drivers/android/binder/page_range.rs b/drivers/android/binder/page_range.rs
index fdd97112ef5c..8e9f5c4819d0 100644
--- a/drivers/android/binder/page_range.rs
+++ b/drivers/android/binder/page_range.rs
@@ -642,15 +642,15 @@ fn drop(self: Pin<&mut Self>) {
unsafe {
bindings::list_lru_walk(
list_lru,
- Some(bindings::rust_shrink_free_page_wrap),
+ Some(rust_shrink_free_page),
ptr::null_mut(),
nr_to_scan,
)
}
}
-const LRU_SKIP: bindings::lru_status = bindings::lru_status_LRU_SKIP;
-const LRU_REMOVED_ENTRY: bindings::lru_status = bindings::lru_status_LRU_REMOVED_RETRY;
+const LRU_SKIP: bindings::lru_status = bindings::lru_status::LRU_SKIP;
+const LRU_REMOVED_ENTRY: bindings::lru_status = bindings::lru_status::LRU_REMOVED_RETRY;
/// # Safety
/// Called by the shrinker.
diff --git a/drivers/android/binder/page_range_helper.c b/drivers/android/binder/page_range_helper.c
deleted file mode 100644
index 496887723ee0..000000000000
--- a/drivers/android/binder/page_range_helper.c
+++ /dev/null
@@ -1,24 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-/* C helper for page_range.rs to work around a CFI violation.
- *
- * Bindgen currently pretends that `enum lru_status` is the same as an integer.
- * This assumption is fine ABI-wise, but once you add CFI to the mix, it
- * triggers a CFI violation because `enum lru_status` gets a different CFI tag.
- *
- * This file contains a workaround until bindgen can be fixed.
- *
- * Copyright (C) 2025 Google LLC.
- */
-#include "page_range_helper.h"
-
-unsigned int rust_shrink_free_page(struct list_head *item,
- struct list_lru_one *list,
- void *cb_arg);
-
-enum lru_status
-rust_shrink_free_page_wrap(struct list_head *item, struct list_lru_one *list,
- void *cb_arg)
-{
- return rust_shrink_free_page(item, list, cb_arg);
-}
diff --git a/drivers/android/binder/page_range_helper.h b/drivers/android/binder/page_range_helper.h
deleted file mode 100644
index 18dd2dd117b2..000000000000
--- a/drivers/android/binder/page_range_helper.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright (C) 2025 Google, Inc.
- */
-
-#ifndef _LINUX_PAGE_RANGE_HELPER_H
-#define _LINUX_PAGE_RANGE_HELPER_H
-
-#include <linux/list_lru.h>
-
-enum lru_status
-rust_shrink_free_page_wrap(struct list_head *item, struct list_lru_one *list,
- void *cb_arg);
-
-#endif /* _LINUX_PAGE_RANGE_HELPER_H */
diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
index 112ec197ef0a..6f02d9720ad2 100644
--- a/rust/bindgen_parameters
+++ b/rust/bindgen_parameters
@@ -19,6 +19,10 @@
# warning. We don't need to peek into it anyway.
--opaque-type spinlock
+# enums that appear in indirect function calls should specify a cfi type
+--newtype-enum lru_status
+--with-attribute-custom-enum=lru_status='#[cfi_encoding="10lru_status"]'
+
# `seccomp`'s comment gets understood as a doctest
--no-doc-comments
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 083cc44aa952..faf3ee634ced 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -149,5 +149,4 @@ const vm_flags_t RUST_CONST_HELPER_VM_NOHUGEPAGE = VM_NOHUGEPAGE;
#if IS_ENABLED(CONFIG_ANDROID_BINDER_IPC_RUST)
#include "../../drivers/android/binder/rust_binder.h"
#include "../../drivers/android/binder/rust_binder_events.h"
-#include "../../drivers/android/binder/page_range_helper.h"
#endif
diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs
index e18c160dad17..854e7c471434 100644
--- a/rust/bindings/lib.rs
+++ b/rust/bindings/lib.rs
@@ -19,6 +19,7 @@
unreachable_pub,
unsafe_op_in_unsafe_fn
)]
+#![feature(cfi_encoding)]
#[allow(dead_code)]
#[allow(clippy::cast_lossless)]
diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs
index 821e286e0daa..b8a515de31ca 100644
--- a/rust/uapi/lib.rs
+++ b/rust/uapi/lib.rs
@@ -24,6 +24,7 @@
unsafe_op_in_unsafe_fn
)]
#![cfg_attr(CONFIG_RUSTC_HAS_UNNECESSARY_TRANSMUTES, allow(unnecessary_transmutes))]
+#![feature(cfi_encoding)]
// Manual definition of blocklisted types.
type __kernel_size_t = usize;
--
2.53.0
^ permalink raw reply related
* [PATCH 30/33] docs: rust: general-information: use real example
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
Currently the example in the documentation shows a version-based name
for the Kconfig example:
RUSTC_VERSION_MIN_107900
The reason behind it was to possibly avoid repetition in case several
features used the same minimum.
However, we ended up preferring to give them a descriptive name for each
feature added even if that could lead to some repetition. In practice,
the repetition has not happened so far, and even if it does at some point,
it is not a big deal.
Thus replace the example in the documentation with one of our current
examples (after removing previous ones from the bump), to show how they
actually look like, and in case someone `grep`s for it.
In addition, it has the advantage that it shows the `RUSTC_HAS_*`
pattern we follow in `init/Kconfig`, similar to the C side.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Documentation/rust/general-information.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
index 91535b2306ed..09234bed272c 100644
--- a/Documentation/rust/general-information.rst
+++ b/Documentation/rust/general-information.rst
@@ -157,5 +157,5 @@ numerical comparisons, one may define a new Kconfig symbol:
.. code-block:: kconfig
- config RUSTC_VERSION_MIN_107900
- def_bool RUSTC_VERSION >= 107900
+ config RUSTC_HAS_SPAN_FILE
+ def_bool RUSTC_VERSION >= 108800
--
2.53.0
^ permalink raw reply related
* [PATCH 29/33] docs: rust: general-information: simplify Kconfig example
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
There is no need to use `def_bool y if <expr>` -- one can simply write
`def_bool <expr>`.
In fact, the simpler form is how we actually use them in practice in
`init/Kconfig`.
Thus simplify the example.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Documentation/rust/general-information.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
index 6146b49b6a98..91535b2306ed 100644
--- a/Documentation/rust/general-information.rst
+++ b/Documentation/rust/general-information.rst
@@ -158,4 +158,4 @@ numerical comparisons, one may define a new Kconfig symbol:
.. code-block:: kconfig
config RUSTC_VERSION_MIN_107900
- def_bool y if RUSTC_VERSION >= 107900
+ def_bool RUSTC_VERSION >= 107900
--
2.53.0
^ permalink raw reply related
* [PATCH 28/33] docs: rust: quick-start: remove GDB/Binutils mention
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
The versions provided nowadays by even a distribution like Debian Stable
(and Debian Old Stable) are newer than those mentioned [1].
Thus remove the workaround.
Note that the minimum binutils version in the kernel is still 2.30, so
one could argue part of the note is still relevant, but it is unlikely
a kernel developer using such an old binutils is enabling Rust on a
modern kernel, especially when using distribution toolchains, e.g. the
Rust minimum version is not satisfied by Debian Old Stable.
So we are at the point where keeping the docs short and relevant for
essentially everyone is probably the better trade-off.
Link: https://packages.debian.org/search?suite=all&searchon=names&keywords=binutils [1]
Link: https://lore.kernel.org/all/CANiq72mCpc9=2TN_zC4NeDMpFQtPXAFvyiP+gRApg2vzspPWmw@mail.gmail.com/
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Documentation/rust/quick-start.rst | 9 ---------
1 file changed, 9 deletions(-)
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
index 5bbe059a8fa3..a6ec3fa94d33 100644
--- a/Documentation/rust/quick-start.rst
+++ b/Documentation/rust/quick-start.rst
@@ -352,12 +352,3 @@ Hacking
To dive deeper, take a look at the source code of the samples
at ``samples/rust/``, the Rust support code under ``rust/`` and
the ``Rust hacking`` menu under ``Kernel hacking``.
-
-If GDB/Binutils is used and Rust symbols are not getting demangled, the reason
-is the toolchain does not support Rust's new v0 mangling scheme yet.
-There are a few ways out:
-
-- Install a newer release (GDB >= 10.2, Binutils >= 2.36).
-
-- Some versions of GDB (e.g. vanilla GDB 10.1) are able to use
- the pre-demangled names embedded in the debug info (``CONFIG_DEBUG_INFO``).
--
2.53.0
^ permalink raw reply related
* [PATCH 27/33] docs: rust: quick-start: remove Nix "unstable channel" note
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
Nix does not need the "unstable channel" note, since its packages are
recent enough even in the stable channel [1][2].
Thus remove it to simplify the documentation.
Link: https://search.nixos.org/packages?channel=25.11&query=rust [1]
Link: https://search.nixos.org/packages?channel=25.11&query=bindgen [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Documentation/rust/quick-start.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
index 1518367324fe..5bbe059a8fa3 100644
--- a/Documentation/rust/quick-start.rst
+++ b/Documentation/rust/quick-start.rst
@@ -68,8 +68,8 @@ of the box, e.g.::
Nix
***
-Nix (unstable channel) provides recent Rust releases and thus it should
-generally work out of the box, e.g.::
+Nix provides recent Rust releases and thus it should generally work out of the
+box, e.g.::
{ pkgs ? import <nixpkgs> {} }:
pkgs.mkShell {
--
2.53.0
^ permalink raw reply related
* [PATCH 26/33] docs: rust: quick-start: remove Gentoo "testing" note
From: Miguel Ojeda @ 2026-04-01 11:45 UTC (permalink / raw)
To: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Trevor Gross, rust-for-linux, linux-kbuild, Lorenzo Stoakes,
Vlastimil Babka, Liam R . Howlett, Uladzislau Rezki, linux-block,
moderated for non-subscribers, Alexandre Ghiti, linux-riscv,
nouveau, dri-devel, Rae Moar, linux-kselftest, kunit-dev,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm, linux-kernel,
Shuah Khan, linux-doc
In-Reply-To: <20260401114540.30108-1-ojeda@kernel.org>
Gentoo does not need the "testing" note, since its packages are recent
enough even in the stable branch [1][2].
Thus remove it to simplify the documentation.
Link: https://packages.gentoo.org/packages/dev-lang/rust [1]
Link: https://packages.gentoo.org/packages/dev-util/bindgen [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
Documentation/rust/quick-start.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
index db08c3a03a4f..1518367324fe 100644
--- a/Documentation/rust/quick-start.rst
+++ b/Documentation/rust/quick-start.rst
@@ -57,8 +57,8 @@ of the box, e.g.::
Gentoo Linux
************
-Gentoo Linux (and especially the testing branch) provides recent Rust releases
-and thus it should generally work out of the box, e.g.::
+Gentoo Linux provides recent Rust releases and thus it should generally work out
+of the box, e.g.::
USE='rust-src rustfmt clippy' emerge dev-lang/rust dev-util/bindgen
--
2.53.0
^ permalink raw reply related
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