linux-kernel - Re: [tip:x86/microcode] x86/microcode_intel_early.c: Early update ucode on Intel's CPU

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Date:	Tue, 11 Dec 2012 16:27:13 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Borislav Petkov <bp@...en8.de>,
	"Yu, Fenghua" <fenghua.yu@...el.com>,
	"mingo@...nel.org" <mingo@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"hpa@...ux.intel.com" <hpa@...ux.intel.com>,
	"linux-tip-commits@...r.kernel.org" 
	<linux-tip-commits@...r.kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Stefano Stabellini <Stefano.Stabellini@...citrix.com>
Subject: Re: [tip:x86/microcode] x86/microcode_intel_early.c: Early update
 ucode on Intel's CPU

On Tue, Dec 11, 2012 at 3:57 PM, H. Peter Anvin <hpa@...or.com> wrote:
> Well, we could invoke it on the bootloader page tables, but as you say
> it may not be a good idea... depending on how much memory we may be
> talking about.  One solution -- which I have to admit is starting to
> sound really good -- is to set up a #PF handler which cycles through a
> set of page tables and creates a "virtual identity map"... it does have
> the advantage of making the entire physical address space available
> without any additional funnies.

so that #PF handler will work before
arch/x86/kernel/setup.c::setup_arch/early_trap_init

early_strap_intit will install another handler there for #PF

for 64bit, moving early_ioremap_init ahead is very simple, like attach patch

but for 32 bit looks like it is not that easy.

Download attachment "early_ioremap_head64.patch" of type "application/octet-stream" (2723 bytes)