From: Peter Zijlstra <peterz@infradead.org>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>, Oleg Nesterov <oleg@redhat.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH, -v2] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug
Date: Thu, 10 Oct 2013 15:10:34 +0200 [thread overview]
Message-ID: <20131010131034.GN3081@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20131010123236.GH30970@tucnak.zalov.cz>
On Thu, Oct 10, 2013 at 02:32:36PM +0200, Jakub Jelinek wrote:
> On Thu, Oct 10, 2013 at 01:56:17PM +0200, Peter Zijlstra wrote:
> > We didn't do version checks for CC_HAVE_ASM_GOTO because of vendor
> > backports; can't we detect this in the same way?
>
> The problem is that it will be harder to check for this as compile time only
> check, and for runtime check you'd need to have the assembly string for
> every architecture and you couldn't do it for cross-compiling anyway.
> So for >= 4.8.3 just assume no
> workaround is needed, otherwise scan assembly.
Right, tedious and error prone it is.. :-)
Would it make sense to create something whereby GCC can tell us about
these things? Maybe something like:
__builtin_bug_fixed(58670)
Which would default return 0, and only return 1 when its a known number.
But yes, I also see why you'd not want to do that. I suppose all I'm
saying is it would be nice to be able to detect some arbitrary issue
being fixed.
> See the follow-up mails, I think placing it immediately after asm goto might
> be better.
Duh indeed, must've missed that when I scanned through the thread :/
next prev parent reply other threads:[~2013-10-10 13:10 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-05 23:44 [x86] BUG: unable to handle kernel paging request at 00740060 Fengguang Wu
2013-10-05 23:47 ` [x86] BUG: unable to handle kernel paging request at 08000060 Fengguang Wu
2013-10-06 7:27 ` Mike Galbraith
2013-10-06 7:36 ` Fengguang Wu
2013-10-07 8:49 ` Peter Zijlstra
2013-10-07 9:17 ` Fengguang Wu
2013-10-07 9:36 ` Peter Zijlstra
2013-10-07 9:46 ` Fengguang Wu
2013-10-07 8:55 ` [x86] BUG: unable to handle kernel paging request at 00740060 Peter Zijlstra
2013-10-07 9:08 ` Peter Zijlstra
2013-10-07 11:32 ` Fengguang Wu
2013-10-07 9:27 ` Fengguang Wu
2013-10-07 18:47 ` Linus Torvalds
2013-10-08 7:51 ` Fengguang Wu
2013-10-08 16:21 ` Linus Torvalds
2013-10-08 17:15 ` [x86] BUG: unable to handle kernel NULL pointer dereference at (null) Fengguang Wu
2013-10-08 17:31 ` Linus Torvalds
2013-10-09 1:09 ` Fengguang Wu
2013-10-09 1:33 ` Linus Torvalds
2013-10-08 18:51 ` [x86] BUG: unable to handle kernel paging request at 00740060 Oleg Nesterov
2013-10-08 19:05 ` Jakub Jelinek
2013-10-08 19:20 ` Linus Torvalds
2013-10-08 19:34 ` Linus Torvalds
2013-10-08 19:35 ` Oleg Nesterov
2013-10-08 19:49 ` Linus Torvalds
2013-10-09 1:43 ` Mike Galbraith
2013-10-08 19:05 ` Linus Torvalds
2013-10-08 16:46 ` Oleg Nesterov
2013-10-08 14:34 ` Oleg Nesterov
2013-10-09 8:04 ` Fengguang Wu
2013-10-09 12:19 ` Fengguang Wu
2013-10-09 12:21 ` Fengguang Wu
2013-10-09 12:27 ` Peter Zijlstra
2013-10-09 12:52 ` Ingo Molnar
2013-10-09 17:18 ` Ingo Molnar
2013-10-10 2:15 ` Mike Galbraith
2013-10-09 12:56 ` Fengguang Wu
2013-10-09 12:43 ` Oleg Nesterov
2013-10-09 14:07 ` Peter Zijlstra
2013-10-09 14:17 ` Oleg Nesterov
2013-10-09 14:32 ` Ingo Molnar
2013-10-09 14:33 ` Peter Zijlstra
2013-10-09 14:46 ` Peter Zijlstra
2013-10-09 18:16 ` Jakub Jelinek
2013-10-09 18:54 ` Linus Torvalds
2013-10-09 19:02 ` Peter Zijlstra
2013-10-09 19:08 ` Jakub Jelinek
2013-10-10 6:22 ` Ingo Molnar
2013-10-10 6:51 ` Jakub Jelinek
2013-10-10 8:04 ` Jakub Jelinek
2013-10-10 8:24 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Ingo Molnar
2013-10-10 8:31 ` Jakub Jelinek
2013-10-10 8:45 ` Ingo Molnar
2013-10-10 8:55 ` [PATCH, -v2] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Ingo Molnar
2013-10-10 11:56 ` Peter Zijlstra
2013-10-10 12:32 ` Jakub Jelinek
2013-10-10 13:10 ` Peter Zijlstra [this message]
2013-10-10 15:04 ` Ingo Molnar
2013-10-10 14:04 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Richard Henderson
2013-10-10 14:27 ` Jakub Jelinek
2013-10-10 15:12 ` [PATCH, -v3] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Ingo Molnar
2013-10-10 16:15 ` Richard Henderson
2013-10-10 16:49 ` Ingo Molnar
2013-10-11 4:35 ` Fengguang Wu
2013-10-11 5:46 ` Ingo Molnar
2013-10-11 6:51 ` Fengguang Wu
2013-10-11 9:30 ` Fengguang Wu
2013-10-12 17:03 ` Ingo Molnar
2013-10-10 8:34 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Ingo Molnar
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