From: Alice Ryhl <aliceryhl@google.com>
To: "Thomas Weißschuh" <linux@weissschuh.net>
Cc: "Thomas Gleixner" <tglx@kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Boqun Feng" <boqun@kernel.org>, "Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Benno Lossin" <lossin@kernel.org>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>,
"Daniel Almeida" <daniel.almeida@collabora.com>,
"Tamir Duberstein" <tamird@kernel.org>,
"Alexandre Courbot" <acourbot@nvidia.com>,
"Onur Özkan" <work@onurozkan.dev>,
linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org
Subject: Re: [PATCH] x86/rust: avoid duplication of RETPOLINE_RUSTFLAGS in recursive kbuild
Date: Thu, 15 Oct 2026 06:42:32 +0000 [thread overview]
Message-ID: <atB12Dve5tdS_lJk@google.com> (raw)
In-Reply-To: <20261013-rust-x86-rethunk-rebuilds-v1-1-d2042a72640b@weissschuh.net>
On Tue, Oct 13, 2026 at 10:42:26AM +0200, Thomas Weißschuh wrote:
> Currently the only modificiation of REPTOLINE_RUSTFLAGS is an append.
> There is no initial (re)set of the value. When kbuild is invoked
> recursively, for example through a top-level `make pacman-pkg`
> invocation, then the inner instance of kbuild will inherit the value
> from the outer one and append the same values again.
>
> Switching between recursive and non-recursive invocations of kbuild in
> the same build tree the command line changes and Rust code is rebuilt.
> While this is harmless, it is slow and unnecessary.
>
> Replace the append operation with a regular assignment. This avoids the
> duplicated values in a recursive kbuild invocation and therefore also
> the spurious rebuilds.
>
> RETPOLINE_CFLAGS is not affected as it is always reset to a fixed value
> further up in the Makefile.
>
> Fixes: d7868550d573 ("x86/rust: support MITIGATION_RETHUNK")
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
prev parent reply other threads:[~2026-10-15 6:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 8:42 [PATCH] x86/rust: avoid duplication of RETPOLINE_RUSTFLAGS in recursive kbuild Thomas Weißschuh
2026-10-15 6:42 ` Alice Ryhl [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=atB12Dve5tdS_lJk@google.com \
--to=aliceryhl@google.com \
--cc=a.hindborg@kernel.org \
--cc=acourbot@nvidia.com \
--cc=bjorn3_gh@protonmail.com \
--cc=boqun@kernel.org \
--cc=bp@alien8.de \
--cc=dakr@kernel.org \
--cc=daniel.almeida@collabora.com \
--cc=dave.hansen@linux.intel.com \
--cc=gary@garyguo.net \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@weissschuh.net \
--cc=lossin@kernel.org \
--cc=mingo@redhat.com \
--cc=ojeda@kernel.org \
--cc=rust-for-linux@vger.kernel.org \
--cc=tamird@kernel.org \
--cc=tglx@kernel.org \
--cc=tmgross@umich.edu \
--cc=work@onurozkan.dev \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox