From: Arvind Sankar <nivedita@alum.mit.edu>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: "Borislav Petkov" <bp@alien8.de>,
"Arvind Sankar" <nivedita@alum.mit.edu>,
"Jakub Jelinek" <jakub@redhat.com>,
jgross@suse.com, x86@kernel.org,
"Kees Cook" <keescook@chromium.org>,
"Peter Zijlstra" <peterz@infradead.org>,
linuxppc-dev@lists.ozlabs.org, "Michael Matz" <matz@suse.de>,
"Nick Desaulniers" <ndesaulniers@google.com>,
LKML <linux-kernel@vger.kernel.org>,
"Sergei Trofimovich" <slyfox@gentoo.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Paul Mackerras" <paulus@samba.org>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Frédéric Pierret (fepitre)" <frederic.pierret@qubes-os.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Martin Liška" <mliska@suse.cz>,
boris.ostrovsky@oracle.com
Subject: Re: [PATCH] x86: Fix early boot crash on gcc-10, next try
Date: Sat, 25 Apr 2020 18:25:04 -0400 [thread overview]
Message-ID: <20200425222504.GA1080319@rani.riverdale.lan> (raw)
In-Reply-To: <20200425191549.GF17645@gate.crashing.org>
On Sat, Apr 25, 2020 at 02:15:49PM -0500, Segher Boessenkool wrote:
> On Sat, Apr 25, 2020 at 08:53:13PM +0200, Borislav Petkov wrote:
> > On Sat, Apr 25, 2020 at 01:37:01PM -0500, Segher Boessenkool wrote:
> > > That is a lot more typing then
> > > asm("");
> >
> > That's why a macro with a hopefully more descriptive name would be
> > telling more than a mere asm("").
>
> My point is that you should explain at *every use* of this why you cannot
> have tail calls *there*. This is very unusual, after all.
>
> There are *very* few places where you want to prevent tail calls, that's
> why there is no attribute for it.
>
>
> Segher
Well, there is -fno-optimize-sibling-calls, but we wouldn't be able to
use it via the optimize attribute for the same reason we couldn't use
no-stack-protector.
WARNING: multiple messages have this Message-ID (diff)
From: Arvind Sankar <nivedita@alum.mit.edu>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: "Jakub Jelinek" <jakub@redhat.com>,
jgross@suse.com, "Michael Matz" <matz@suse.de>,
"Kees Cook" <keescook@chromium.org>,
"Frédéric Pierret (fepitre)" <frederic.pierret@qubes-os.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Martin Liška" <mliska@suse.cz>,
x86@kernel.org, "Nick Desaulniers" <ndesaulniers@google.com>,
LKML <linux-kernel@vger.kernel.org>,
"Sergei Trofimovich" <slyfox@gentoo.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
"Arvind Sankar" <nivedita@alum.mit.edu>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Paul Mackerras" <paulus@samba.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org, boris.ostrovsky@oracle.com
Subject: Re: [PATCH] x86: Fix early boot crash on gcc-10, next try
Date: Sat, 25 Apr 2020 18:25:04 -0400 [thread overview]
Message-ID: <20200425222504.GA1080319@rani.riverdale.lan> (raw)
In-Reply-To: <20200425191549.GF17645@gate.crashing.org>
On Sat, Apr 25, 2020 at 02:15:49PM -0500, Segher Boessenkool wrote:
> On Sat, Apr 25, 2020 at 08:53:13PM +0200, Borislav Petkov wrote:
> > On Sat, Apr 25, 2020 at 01:37:01PM -0500, Segher Boessenkool wrote:
> > > That is a lot more typing then
> > > asm("");
> >
> > That's why a macro with a hopefully more descriptive name would be
> > telling more than a mere asm("").
>
> My point is that you should explain at *every use* of this why you cannot
> have tail calls *there*. This is very unusual, after all.
>
> There are *very* few places where you want to prevent tail calls, that's
> why there is no attribute for it.
>
>
> Segher
Well, there is -fno-optimize-sibling-calls, but we wouldn't be able to
use it via the optimize attribute for the same reason we couldn't use
no-stack-protector.
next prev parent reply other threads:[~2020-04-25 22:25 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-14 16:44 [PATCH] x86: fix early boot crash on gcc-10 Sergei Trofimovich
2020-03-16 13:04 ` Peter Zijlstra
2020-03-16 13:26 ` Jakub Jelinek
2020-03-16 13:42 ` Peter Zijlstra
2020-03-16 17:54 ` Borislav Petkov
2020-03-16 18:03 ` Jakub Jelinek
2020-03-17 14:36 ` Borislav Petkov
2020-03-17 14:39 ` Jakub Jelinek
2020-03-17 14:49 ` Borislav Petkov
2020-03-17 16:35 ` David Laight
2020-03-25 13:31 ` Borislav Petkov
2020-03-26 21:54 ` Sergei Trofimovich
2020-03-26 22:35 ` Borislav Petkov
2020-03-28 8:48 ` [PATCH v2] " Sergei Trofimovich
2020-04-13 14:15 ` [tip: x86/urgent] x86: Fix " tip-bot2 for Sergei Trofimovich
2020-04-13 16:35 ` [PATCH v2] x86: fix " Borislav Petkov
2020-04-14 13:50 ` Michael Matz
2020-04-15 7:48 ` Borislav Petkov
2020-04-15 14:53 ` Michael Matz
2020-04-15 22:19 ` Sergei Trofimovich
2020-04-17 7:57 ` Borislav Petkov
2020-04-17 8:07 ` Jakub Jelinek
2020-04-17 8:42 ` Borislav Petkov
2020-04-17 8:58 ` Jakub Jelinek
2020-04-17 9:09 ` Borislav Petkov
2020-04-17 18:15 ` Nick Desaulniers
2020-04-17 18:22 ` Nick Desaulniers
2020-04-17 19:06 ` Jakub Jelinek
2020-04-17 19:49 ` Nick Desaulniers
2020-04-17 19:53 ` Nick Desaulniers
2020-04-20 14:04 ` Michael Matz
2020-04-22 10:23 ` Borislav Petkov
2020-04-22 11:40 ` Peter Zijlstra
2020-04-22 13:49 ` Borislav Petkov
2020-04-22 13:55 ` Jakub Jelinek
2020-04-22 14:16 ` Martin Liška
2020-04-22 15:06 ` Michael Matz
2020-04-22 16:53 ` Borislav Petkov
2020-04-22 17:02 ` Jakub Jelinek
2020-04-22 18:47 ` Nick Desaulniers
2020-04-22 18:55 ` Nick Desaulniers
2020-04-22 19:21 ` Borislav Petkov
2020-04-22 21:05 ` Nick Desaulniers
2020-04-22 21:26 ` Borislav Petkov
2020-04-22 22:57 ` Nick Desaulniers
2020-04-23 12:53 ` Borislav Petkov
2020-04-23 16:12 ` [PATCH] x86: Fix early boot crash on gcc-10, next try Borislav Petkov
2020-04-23 17:30 ` Borislav Petkov
2020-04-23 18:02 ` Nick Desaulniers
2020-04-23 18:27 ` Borislav Petkov
2020-04-27 11:37 ` [tip: x86/build] x86/build: Check whether the compiler is sane tip-bot2 for Borislav Petkov
2020-04-23 19:40 ` [PATCH] x86: Fix early boot crash on gcc-10, next try Kees Cook
2020-04-25 1:46 ` Arvind Sankar
2020-04-25 8:57 ` Borislav Petkov
2020-04-25 11:09 ` Jürgen Groß
2020-04-25 15:04 ` Arvind Sankar
2020-04-25 15:04 ` Arvind Sankar
2020-04-25 17:31 ` Borislav Petkov
2020-04-25 17:31 ` Borislav Petkov
2020-04-25 17:52 ` Borislav Petkov
2020-04-25 17:52 ` Borislav Petkov
2020-04-27 17:07 ` David Laight
2020-04-27 17:07 ` David Laight
2020-04-25 18:37 ` Segher Boessenkool
2020-04-25 18:37 ` Segher Boessenkool
2020-04-25 18:53 ` Borislav Petkov
2020-04-25 18:53 ` Borislav Petkov
2020-04-25 19:15 ` Segher Boessenkool
2020-04-25 19:15 ` Segher Boessenkool
2020-04-25 22:17 ` Borislav Petkov
2020-04-25 22:17 ` Borislav Petkov
2020-04-25 22:25 ` Arvind Sankar [this message]
2020-04-25 22:25 ` Arvind Sankar
2020-04-17 10:38 ` [PATCH v2] x86: fix early boot crash on gcc-10 Peter Zijlstra
2020-04-18 13:12 ` David Laight
2020-04-17 10:41 ` Peter Zijlstra
2020-03-16 18:20 ` [PATCH] " Arvind Sankar
2020-03-16 18:54 ` Arvind Sankar
2020-03-16 19:53 ` Arvind Sankar
2020-03-16 20:08 ` Jakub Jelinek
2020-03-16 20:40 ` Arvind Sankar
2020-03-16 22:12 ` Sergei Trofimovich
2020-03-17 11:46 ` Jakub Jelinek
2020-03-17 18:10 ` Sergei Trofimovich
2020-03-16 18:22 ` Arvind Sankar
2020-03-26 23:16 ` [PATCH v2] " Sergei Trofimovich
2020-04-27 11:37 ` [tip: x86/build] x86: Fix early boot crash on gcc-10, next try tip-bot2 for Borislav Petkov
2020-05-15 11:20 ` [tip: x86/urgent] x86: Fix early boot crash on gcc-10, third try tip-bot2 for Borislav Petkov
2020-05-19 11:49 ` Sasha Levin
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=20200425222504.GA1080319@rani.riverdale.lan \
--to=nivedita@alum.mit.edu \
--cc=boris.ostrovsky@oracle.com \
--cc=bp@alien8.de \
--cc=clang-built-linux@googlegroups.com \
--cc=frederic.pierret@qubes-os.org \
--cc=hpa@zytor.com \
--cc=jakub@redhat.com \
--cc=jgross@suse.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=luto@kernel.org \
--cc=matz@suse.de \
--cc=mingo@redhat.com \
--cc=mliska@suse.cz \
--cc=ndesaulniers@google.com \
--cc=paulus@samba.org \
--cc=peterz@infradead.org \
--cc=segher@kernel.crashing.org \
--cc=slyfox@gentoo.org \
--cc=tglx@linutronix.de \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.