Messages in this thread | | | From | Keith Owens <> | Subject | Re: [PATCH][RFC] PentiumPro/II split in x86 config | Date | Tue, 28 May 2002 10:15:52 +1000 |
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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.
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