Message-ID: <530E1A35.40506@zytor.com>
Date: Wed, 26 Feb 2014 08:45:41 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Matthew Garrett <mjg59@srcf.ucam.org>,
        Chris Bainbridge <chris.bainbridge@gmail.com>
CC: davej@redhat.com, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: set Pentium M as PAE capable
References: <20140225060146.GA4339@debian.local> <530C7465.2080600@zytor.com> <20140225162611.GA31902@redhat.com> <530CCFD2.3050007@zytor.com> <20140226121256.GA8494@debian.local> <20140226164433.GA19341@srcf.ucam.org>
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On 02/26/2014 08:44 AM, Matthew Garrett wrote:
> On Wed, Feb 26, 2014 at 07:12:59PM +0700, Chris Bainbridge wrote:
> 
>> The basic findings of the bug discussion is that people are successfully
>> running PAE kernels on Pentium M (for some unknown reason Grub skips the
>> validate_cpu code in the kernel, so existing PAE kernels will run
>> unmodified, although they do fail when booted with syslinux), and people
>> are using a user-space hack to add "pae" to /proc/cpuinfo.
> 
> grub is jumping to the 32-bit entry point and skipping the entire real 
> mode setup code. Bad grub.
> 

Yes.  Grub can be made to behave sanely by using "linux16" and
"initrd16", but of course none of the distros do it that way.

There are much worse problems with that.

	-hpa

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