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SubjectRe: [patch 1/2] F00F bug fixup for i386 - use immediate values
On Fri, Jul 13, 2007 at 09:26:43PM -0400, Mathieu Desnoyers wrote:
> Use the faster immediate values for F00F bug handling in do_page_fault.

> --- linux-2.6-lttng.orig/arch/i386/mm/fault.c
> +++ linux-2.6-lttng/arch/i386/mm/fault.c
> @@ -492,7 +493,7 @@
> /*
> * Pentium F0 0F C7 C8 bug workaround.
> */
> - if (boot_cpu_data.f00f_bug) {
> + immediate_if (&f00f_bug_fix) {

This code is not called during normal pagefaults and even during invalid
userspace accesses.

Out of curiosity, I inserted printk() at this place to see where I was
wrong. I got only two hits:

Checking if this processor honours the WP bit even in supervisor mode... do_page_fault:
Freeing unused kernel memory: 116k freed
do_page_fault:

Resume: nobody gives a fuck about performance of this particular if,
so conversion it totally pointless.

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