From: "H. Peter Anvin" <hpa@zytor.com>
To: "Borislav Petkov" <bp@alien8.de>,
"Geert Uytterhoeven" <geert@linux-m68k.org>,
"Borislav Petkov" <borislav.petkov@amd.com>,
"Toralf Förster" <toralf.foerster@gmx.de>,
user-mode-linux-devel@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86, hweight: Fix UML boot crash
Date: Sun, 30 May 2010 11:36:16 -0700 [thread overview]
Message-ID: <4C02B020.2040103@zytor.com> (raw)
In-Reply-To: <20100530170346.GC1565@liondog.tnic>
On 05/30/2010 10:03 AM, Borislav Petkov wrote:
> Obviously UML cannot stomach callee reg-saving trickery
> introduced with d61931d89be506372d01a90d1755f6d0a9fafe2d (x86:
> Add optimized popcnt variants) and oopses during boot:
> http://marc.info/?l=linux-kernel&m=127522065202435&w=2
>
> Go ahead and fall back to the software hweight* routines on UML.
I actually don't understand why UML can't stomach that... it would work
exactly the same in userspace as in kernel space. The only thing that I
can think of is if UML overrides the CFLAGS including the per-file
CFLAGS, but that would seem to cause all kinds of other issues.
I would also be a lot happier if this was handled in
<asm/arch_hweight.h> than in <asm/bitops.h>. Finally, if UML really
can't handle this, then ARCH_HWEIGHT_CFLAGS should be disabled on UML.
This bothers me, because it really feels like something is fundamentally
broken in UML tryingto track the upstream architecture, and this is just
a bandage.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2010-05-30 18:40 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-27 17:44 current git kernel crashes UML system during boot Toralf Förster
2010-05-30 11:39 ` Geert Uytterhoeven
2010-05-30 11:57 ` Geert Uytterhoeven
2010-05-30 15:02 ` Borislav Petkov
2010-05-30 15:18 ` Geert Uytterhoeven
2010-05-30 15:46 ` Borislav Petkov
2010-05-30 15:28 ` Toralf Förster
2010-05-30 17:03 ` [PATCH] x86, hweight: Fix UML boot crash Borislav Petkov
2010-05-30 18:36 ` H. Peter Anvin [this message]
2010-05-30 19:39 ` Borislav Petkov
2010-05-30 20:17 ` Borislav Petkov
2010-05-30 21:09 ` H. Peter Anvin
2010-06-12 13:34 ` [uml-devel] " Paolo Giarrusso
2010-06-12 14:18 ` Borislav Petkov
2010-06-12 16:01 ` Paolo Giarrusso
2010-06-12 16:34 ` Borislav Petkov
2010-06-12 18:37 ` Geert Uytterhoeven
2010-06-13 6:58 ` Borislav Petkov
2010-05-31 13:55 ` Toralf Förster
2010-05-31 14:10 ` Borislav Petkov
2010-05-31 14:36 ` Toralf Förster
2010-06-14 9:49 ` Toralf Förster
2010-06-14 10:26 ` [uml-devel] " Paolo Giarrusso
2010-06-14 12:54 ` Toralf Förster
2010-06-14 13:00 ` Borislav Petkov
2010-06-14 13:44 ` Toralf Förster
2010-06-14 14:39 ` Geert Uytterhoeven
2010-06-14 15:11 ` Toralf Förster
2010-06-14 15:20 ` H. Peter Anvin
2010-05-31 14:25 ` [uml-devel] " Boaz Harrosh
2010-05-31 2:32 ` Jeff Dike
2010-05-31 13:51 ` Borislav Petkov
2010-05-31 15:56 ` Jeff Dike
2010-05-31 16:29 ` Borislav Petkov
[not found] ` <tip-cc7f0a7b3004a4ca0bfef0e1ca79f2e0da6ca1b0@git.kernel.org>
2010-06-09 22:43 ` [tip:x86/urgent] " H. Peter Anvin
2010-06-10 5:32 ` Geert Uytterhoeven
2010-06-10 6:26 ` H. Peter Anvin
2010-06-09 8:04 ` [PATCH resend] um, " Boaz Harrosh
2010-06-09 8:09 ` [uml-devel] " Boaz Harrosh
2010-06-09 8:46 ` Geert Uytterhoeven
2010-06-09 9:08 ` Boaz Harrosh
2010-06-09 9:32 ` Américo Wang
2010-06-09 18:29 ` H. Peter Anvin
2010-06-14 16:08 ` Boaz Harrosh
2010-06-14 16:41 ` H. Peter Anvin
2010-06-14 18:18 ` Boaz Harrosh
2010-06-09 16:39 ` Boaz Harrosh
2010-06-10 23:43 ` [tip:x86/urgent] um, hweight: Fix UML boot crash due to x86 optimized hweight tip-bot for Borislav Petkov
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