From: Petr Mladek <pmladek@suse.com>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: "Miguel Ojeda" <ojeda@kernel.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
rust-for-linux <rust-for-linux@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
"Wedson Almeida Filho" <wedsonaf@google.com>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Geoffrey Thomas" <geofft@ldpreload.com>,
"Finn Behrens" <me@kloenk.de>,
"Adam Bratschi-Kaye" <ark.email@gmail.com>,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Sumera Priyadarsini" <sylphrenadin@gmail.com>,
"Sven Van Asbroeck" <thesven73@gmail.com>,
"Gary Guo" <gary@garyguo.net>,
"Boris-Chengbiao Zhou" <bobo1239@web.de>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Fox Chen" <foxhlchen@gmail.com>,
"Dan Robertson" <daniel.robertson@starlab.io>,
"Viktor Garske" <viktor@v-gar.de>,
"Dariusz Sosnowski" <dsosnowski@dsosnowski.pl>,
"Léo Lanteri Thauvin" <leseulartichaut@gmail.com>,
"Niklas Mohrin" <dev@niklasmohrin.de>,
"Gioh Kim" <gurugio@gmail.com>, "Daniel Xu" <dxu@dxuuu.xyz>,
"Milan Landaverde" <milan@mdaverde.com>,
"Morgan Bartlett" <mjmouse9999@gmail.com>,
"Maciej Falkowski" <m.falkowski@samsung.com>,
"Jiapeng Chong" <jiapeng.chong@linux.alibaba.com>,
"Sergey Senozhatsky" <senozhatsky@chromium.org>,
"Steven Rostedt" <rostedt@goodmis.org>,
"John Ogness" <john.ogness@linutronix.de>
Subject: Re: [PATCH v4 10/20] rust: add `kernel` crate
Date: Thu, 24 Feb 2022 13:39:27 +0100 [thread overview]
Message-ID: <Yhd8f93+Pw/7KdRV@alley> (raw)
In-Reply-To: <CANiq72n0sg_fizEk_kK=p8ROmWTrwdzqu1LD4SQdKUNLbK9ENA@mail.gmail.com>
On Tue 2022-02-22 13:48:16, Miguel Ojeda wrote:
> Hi Petr,
>
> On Tue, Feb 22, 2022 at 10:06 AM Petr Mladek <pmladek@suse.com> wrote:
> >
> > What exactly should we keep in sync, please?
> >
> > I see only handling of KERN_* prefix in print.rs. I do not see there
> > any counter part of LOG_LINE_MAX, CONSOLE_LOG_MAX, or PREFIX_MAX.
>
> Good catch! We had a buffer on the Rust side in the past, but that is
> not the case anymore since commit 9e8bd679ecf2 ("Support Rust
> `core::fmt::Argument` in vsprintf") on our side, so we will remove the
> comment.
Great :-)
> > I am sorry but I am not familiar with rust. What are these limits
> > 2 and 10 used for, please?
> >
> > I guess that 2 is the size of a single KERN_* identifier.
> > But what is 10?
> >
> > Note that printk() format prefix is typically just a single KERN_*
> > identifier. But there might be more. Well, in practice only the
> > following combination makes sense: KERN_CONT + KERN_<LEVEL>.
>
> What we are doing here is generating compile-time format strings that
> are then used by the `pr_*!` macros (which call the C side `printk()`
> with one of the strings).
I see. We are on the safe side then.
> In other words, this is not parsing arbitrary `printk()` format
> strings (which I am guessing something like that is your concern --
> please let me know if I got it wrong).
Yes, this was my concern.
> > Finally, is there any way to test whether any change in the printk
> > code breaks the rust support?
>
> One way is to compile the code, e.g. the `assert!`s in the `generate`
> function run at compile-time, thus they provide a first layer of
> defense.
>
> Another way is to use `samples/rust/print.rs` which we run in the CI
> as a black box test.
>
> Is that what you had in mind? Or something like unit tests or self tests?
I had in mind any tests that I might run [*] to be sure that changes in
the native printk code does not break Rust support.
The compile test and samples/rust/print.rs do some basic tests and
might enough for now.
[*] To make it clear. I am not going to run the tests at this stage.
But I might be useful once this patchset is accepted upstream.
But it also might be enough to wait for results from your CI.
I hope that we will not break it that often.
Best Regards,
Petr
next prev parent reply other threads:[~2022-02-24 12:39 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-12 13:03 [PATCH v4 00/20] Rust support Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 01/20] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 02/20] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-02-22 8:19 ` Petr Mladek
2022-02-22 12:45 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 03/20] kallsyms: use the correct buffer size for symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 04/20] rust: add C helpers Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 05/20] rust: add `compiler_builtins` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 06/20] rust: add `alloc` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 07/20] rust: add `build_error` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 08/20] rust: add `macros` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 09/20] rust: add `kernel` crate's `sync` module Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 10/20] rust: add `kernel` crate Miguel Ojeda
2022-02-14 5:27 ` Sergey Senozhatsky
2022-02-14 13:36 ` Miguel Ojeda
2022-02-22 9:06 ` Petr Mladek
2022-02-22 12:48 ` Miguel Ojeda
2022-02-24 12:39 ` Petr Mladek [this message]
2022-02-12 13:03 ` [PATCH v4 11/20] rust: export generated symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 12/20] vsprintf: add new `%pA` format specifier Miguel Ojeda
2022-02-14 10:18 ` Andy Shevchenko
2022-02-14 10:52 ` Rasmus Villemoes
2022-02-14 11:36 ` David Laight
2022-02-14 14:04 ` Miguel Ojeda
2022-02-14 12:12 ` Miguel Ojeda
2022-02-22 9:29 ` Petr Mladek
2022-02-22 10:35 ` Rasmus Villemoes
2022-02-24 9:55 ` Petr Mladek
2022-02-14 12:27 ` Miguel Ojeda
2022-02-14 13:54 ` Andy Shevchenko
2022-02-14 14:56 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 13/20] scripts: add `generate_rust_analyzer.py` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 14/20] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 15/20] docs: add Rust documentation Miguel Ojeda
2022-02-14 10:47 ` Akira Yokosawa
2022-02-14 12:44 ` Miguel Ojeda
2022-02-16 13:37 ` Akira Yokosawa
2022-02-16 14:02 ` Miguel Ojeda
2022-03-17 8:19 ` Miguel Ojeda
2022-03-17 14:50 ` Akira Yokosawa
2022-03-18 13:12 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 16/20] Kbuild: add Rust support Miguel Ojeda
2022-02-12 14:16 ` Russell King (Oracle)
2022-02-12 15:47 ` Miguel Ojeda
2022-02-12 16:18 ` Russell King (Oracle)
2022-02-12 18:32 ` Miguel Ojeda
2022-02-12 18:27 ` John Paul Adrian Glaubitz
2022-02-12 18:57 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 17/20] samples: add Rust examples Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 18/20] MAINTAINERS: Rust Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 19/20] [RFC] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 20/20] [RFC] drivers: android: Binder IPC " Miguel Ojeda
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