From: Keith Owens <kaos@ocs.com.au>
To: "J.A. Magallon" <jamagallon@able.es>
Cc: Lista Linux-Kernel <linux-kernel@vger.kernel.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Marcelo Tosatti <marcelo@conectiva.com.br>
Subject: Re: [PATCH][RFC] PentiumPro/II split in x86 config
Date: Tue, 28 May 2002 10:15:52 +1000 [thread overview]
Message-ID: <2195.1022544952@ocs3.intra.ocs.com.au> (raw)
In-Reply-To: Your message of "Mon, 27 May 2002 16:54:20 +0200." <20020527145420.GA6738@werewolf.able.es>
On Mon, 27 May 2002 16:54:20 +0200,
"J.A. Magallon" <jamagallon@able.es> wrote:
>Due to Alan's advice, it also adds a check that will panic if a PII or
>higher kernel is run on a PPro or lesser (plz, I put that code in the
>place I thought it was the best, but probably I'm wrong...).
>+static void __init check_intel_compat(struct cpuinfo_x86 *c)
>+{
>+#if defined(CONFIG_MPENTIUMII) || defined(CONFIG_MPENTIUMIII) || defined(CONFIG_MPENTIUM4)
>+ if (c->x86 <= 5)
>+ panic("Kernel is unsafe/incompatible with this CPU model. Check your build settings !\n");
>+#endif
>+}
Don't rely on that working. When you compile with -march=i686, gcc
emits cmov instructions all over the place, including in printk code.
The first cmov takes a fault and tries to panic, the panic code uses
printk which hits a second cmov and the machine is dead with no
messages.
prev parent reply other threads:[~2002-05-28 0:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-27 14:54 J.A. Magallon
2002-05-27 17:31 ` Alan Cox
2002-05-27 21:59 ` J.A. Magallon
2002-05-28 1:29 ` Arnaldo Carvalho de Melo
2002-05-28 2:05 ` Keith Owens
2002-05-28 2:16 ` Arnaldo Carvalho de Melo
2002-05-28 2:24 ` Keith Owens
2002-05-28 2:35 ` Arnaldo Carvalho de Melo
2002-05-28 2:55 ` Miles Bader
2002-05-28 3:02 ` Arnaldo Carvalho de Melo
2002-05-28 14:03 ` J.A. Magallon
2002-05-28 14:30 ` Mikael Pettersson
2002-05-28 15:00 ` David Woodhouse
2002-05-28 18:39 ` Albert D. Cahalan
2002-05-28 16:16 ` Miles Bader
2002-05-28 14:45 ` Roland Dreier
2002-05-29 4:23 ` Rusty Russell
2002-05-29 4:27 ` Arnaldo Carvalho de Melo
2002-05-29 14:06 ` Dave Jones
2002-05-28 0:15 ` Keith Owens [this message]
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