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From: "matz at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/88345] -Os overrides -falign-functions=N on the command line
Date: Wed, 06 Dec 2023 18:02:35 +0000	[thread overview]
Message-ID: <bug-88345-4-ubZw0sMe6e@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-88345-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345

--- Comment #21 from Michael Matz <matz at gcc dot gnu.org> ---
(In reply to Jan Hubicka from comment #20)
> > 
> > Live patching (user-space) doesn't depend on any particular alignment of
> > functions, on x86-64 at least.  (The plan for other architectures wouldn't need
> > any specific alignment either).  Note that the above complaints about missing
> > alignment is for kernel (!) ftrace/livepatching on arm64 (!), not on x86_64.
> 
> I had impression that x86-64 also needs forced alignment so the patching
> can be always done atomically.  But it is not a big practical difference
> if we go with a flag specifying minimal function alignment.

Not for userspace live patching (it's done while the process is stopped).
kernel live patching may or may not need it.  Point being that alignment
shouldn't be implied by the live patching options as its orthogonal.

  parent reply	other threads:[~2023-12-06 18:02 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-88345-4@http.gcc.gnu.org/bugzilla/>
2020-09-11 10:52 ` koen.zandberg at inria dot fr
2022-09-01  7:24 ` kito at gcc dot gnu.org
2023-01-12 11:34 ` mark at kernel dot org
2023-01-12 16:11 ` egallager at gcc dot gnu.org
2023-01-13 12:56 ` mark at kernel dot org
2023-01-17 16:26 ` ktkachov at gcc dot gnu.org
2023-01-17 16:37 ` kito at gcc dot gnu.org
2023-01-23 14:15 ` mark at kernel dot org
2023-09-12 11:47 ` rguenth at gcc dot gnu.org
2023-09-12 12:35 ` matz at gcc dot gnu.org
2023-11-22 13:20 ` hubicka at gcc dot gnu.org
2023-12-06  9:38 ` hubicka at gcc dot gnu.org
2023-12-06 13:38 ` matz at gcc dot gnu.org
2023-12-06 17:20 ` hubicka at ucw dot cz
2023-12-06 18:02 ` matz at gcc dot gnu.org [this message]
2023-12-07 10:49 ` jamborm at gcc dot gnu.org
2024-01-01 20:22 ` hubicka at gcc dot gnu.org
2024-01-24 17:13 ` cvs-commit at gcc dot gnu.org

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