public inbox for linux-kbuild@vger.kernel.org
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	Michal Marek <michal.lkml@markovi.net>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Sam Ravnborg <sam@ravnborg.org>, X86 ML <x86@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Changbin Du <changbin.du@gmail.com>
Subject: Re: [PATCH] kbuild: Remove CONFIG_DEBUG_SECTION_MISMATCH
Date: Fri, 8 Apr 2022 21:14:35 +0200	[thread overview]
Message-ID: <YlCJm8iQBPSOWIT5@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAK7LNARvFcQgEB1b0L6giwx0vD7wU9L-OZ5jvm1c5+StLjeOYQ@mail.gmail.com>

On Sat, Apr 09, 2022 at 03:29:21AM +0900, Masahiro Yamada wrote:
> Is [2] caused by dead code that was not optimized out
> due to the unusual inlining decisions by the compiler ?

The complaint is due to SMAP validation; objtool will scream if there's
a CALL in between STAC/CLAC. The thinking is that since they open a
security window, we want tight code between them. We also very much
don't want tracing and other funnies to happen there. As such, any CALL
is dis-allowed.

This weird option is having us upgrade quite a few 'inline' to
'__always_inline'.

  reply	other threads:[~2022-04-08 19:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-08 16:21 [PATCH] kbuild: Remove CONFIG_DEBUG_SECTION_MISMATCH Josh Poimboeuf
2022-04-08 18:29 ` Masahiro Yamada
2022-04-08 19:14   ` Peter Zijlstra [this message]
2022-04-08 20:08     ` Nick Desaulniers
2022-04-08 20:16       ` Nick Desaulniers
2022-04-08 20:32       ` Peter Zijlstra
2022-04-08 20:48         ` Peter Zijlstra
2022-04-09 10:33     ` Arnd Bergmann
2022-04-09  0:48   ` Josh Poimboeuf
2022-04-20 17:03     ` Nick Desaulniers
2022-04-20 17:30       ` Josh Poimboeuf
2022-04-08 20:27 ` Nick Desaulniers

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=YlCJm8iQBPSOWIT5@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=arnd@arndb.de \
    --cc=changbin.du@gmail.com \
    --cc=jpoimboe@redhat.com \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=masahiroy@kernel.org \
    --cc=michal.lkml@markovi.net \
    --cc=ndesaulniers@google.com \
    --cc=sam@ravnborg.org \
    --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