From: "Arnd Bergmann" <arnd@arndb.de>
To: "Ian Rogers" <irogers@google.com>,
"Thomas Gleixner" <tglx@kernel.org>,
"Andy Lutomirski" <luto@kernel.org>,
"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
"Stefan Kerkmann" <s.kerkmann@pengutronix.de>,
"Marc Kleine-Budde" <mkl@pengutronix.de>,
"Christophe Leroy" <chleroy@kernel.org>
Cc: "David Laight" <david.laight.linux@gmail.com>,
"Arnaldo Carvalho de Melo" <acme@kernel.org>,
"Namhyung Kim" <namhyung@kernel.org>,
"Eric Biggers" <ebiggers@google.com>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
linux-arm-kernel@lists.infradead.org,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/2] vdso: Add VDSO_UNALIGNED_PACKED config option for ARMv5
Date: Tue, 20 Oct 2026 00:12:57 +0200 [thread overview]
Message-ID: <31fe09f6-0a14-40fc-8ad8-c03998fb1f5c@app.fastmail.com> (raw)
In-Reply-To: <20261019201257.3805356-1-irogers@google.com>
On Mon, Oct 19, 2026, at 22:12, Ian Rogers wrote:
> +
> +config VDSO_UNALIGNED_PACKED
> + bool
> + default CPU_32v5
> + help
> + Use packed structs rather than memcpy() in include/vdso/unaligned.h
> + for unaligned memory accesses. Enabled on ARMv5 where GCC may emit
> + out-of-line memcpy() calls instead of inlining byte accesses.
As explained, I think this misrepresents the problem as Arm specific and
isn't the correct method for -munaligned-access targets on Arm, which
include CPU_32v3, CPU_32v4 and CPU_32v4T along with CPU_32v5.
I still hope we can use a version that just produces the intended code
on both -munaligned-access and -mno-unaligned-access targets like the
old version did.
Arnd
next prev parent reply other threads:[~2026-10-19 22:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-19 20:12 Ian Rogers
2026-10-19 20:12 ` [PATCH v1 2/2] tools headers: Update the vdso/unaligned.h copy with the kernel sources Ian Rogers
2026-10-19 22:12 ` Arnd Bergmann [this message]
2026-10-20 6:44 ` [PATCH v1 1/2] vdso: Add VDSO_UNALIGNED_PACKED config option for ARMv5 Marc Kleine-Budde
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=31fe09f6-0a14-40fc-8ad8-c03998fb1f5c@app.fastmail.com \
--to=arnd@arndb.de \
--cc=Jason@zx2c4.com \
--cc=acme@kernel.org \
--cc=chleroy@kernel.org \
--cc=david.laight.linux@gmail.com \
--cc=ebiggers@google.com \
--cc=irogers@google.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mkl@pengutronix.de \
--cc=namhyung@kernel.org \
--cc=s.kerkmann@pengutronix.de \
--cc=tglx@kernel.org \
--cc=vincenzo.frascino@arm.com \
--cc=viro@zeniv.linux.org.uk \
/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
all inboxes | Powered by JetHome®