From: Johan Hovold <johan@kernel.org>
To: Rob Herring <robh+dt@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jessica Yu <jeyu@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frank Rowand <frowand.list@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
David Miller <davem@davemloft.net>,
Jakub Jelinek <jakub@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Daniel Kurtz <djkurtz@chromium.org>,
linux-arch@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
linux-kernel@vger.kernel.org, Johan Hovold <johan@kernel.org>
Subject: Re: [PATCH v2 2/8] earlycon: simplify earlycon-table implementation
Date: Fri, 4 Dec 2020 15:03:45 +0100 [thread overview]
Message-ID: <X8pBwTl7nZoOQ18m@localhost> (raw)
In-Reply-To: <20201123102319.8090-3-johan@kernel.org>
Greg,
On Mon, Nov 23, 2020 at 11:23:13AM +0100, Johan Hovold wrote:
> Instead of using the array-of-pointers trick to avoid having gcc mess up
> the earlycon array stride, specify type alignment when declaring entries
> to prevent gcc from increasing alignment.
>
> This is essentially an alternative (one-line) fix to the problem
> addressed by commit dd709e72cb93 ("earlycon: Use a pointer table to fix
> __earlycon_table stride").
>
> gcc can increase the alignment of larger objects with static extent as
> an optimisation, but this can be suppressed by using the aligned
> attribute when declaring variables.
>
> Note that we have been relying on this behaviour for kernel parameters
> for 16 years and it indeed hasn't changed since the introduction of the
> aligned attribute in gcc-3.1.
>
> Signed-off-by: Johan Hovold <johan@kernel.org>
Could you pick this one up for 5.11?
Johan
next prev parent reply other threads:[~2020-12-04 14:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 10:23 [PATCH v2 0/8] linker-section array fix and clean ups Johan Hovold
2020-11-23 10:23 ` [PATCH v2 1/8] of: fix linker-section match-table corruption Johan Hovold
2020-12-04 14:02 ` Johan Hovold
2020-11-23 10:23 ` [PATCH v2 2/8] earlycon: simplify earlycon-table implementation Johan Hovold
2020-12-04 14:03 ` Johan Hovold [this message]
2020-12-04 14:44 ` Greg Kroah-Hartman
2020-11-23 10:23 ` [PATCH v2 3/8] module: drop version-attribute alignment Johan Hovold
2020-11-23 10:23 ` [PATCH v2 4/8] module: simplify version-attribute handling Johan Hovold
2020-11-23 10:23 ` [PATCH v2 5/8] init: use type alignment for kernel parameters Johan Hovold
2020-11-23 10:23 ` [PATCH v2 6/8] params: drop redundant "unused" attributes Johan Hovold
2020-11-23 10:23 ` [PATCH v2 7/8] params: use type alignment for kernel parameters Johan Hovold
2020-11-23 10:23 ` [PATCH v2 8/8] params: clean up module-param macros Johan Hovold
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