From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [RFC PATCH] x86: Make sure verify_cpu has a good stack
Date: Wed, 2 Mar 2016 13:54:50 -0800 [thread overview]
Message-ID: <56D7612A.4080107@zytor.com> (raw)
In-Reply-To: <20160302214654.GK8362@pd.tnic>
On 03/02/16 13:46, Borislav Petkov wrote:
> On Wed, Mar 02, 2016 at 01:35:09PM -0800, H. Peter Anvin wrote:
>> You're not actually testing anything as the real issue is what happens
>> with a relocating bootloader.
>
> Hmm, how would that relocation happen so that va - __START_KERNEL_map
> doesn't give pa?
>
> Or do you mean something else with "relocating bootloader"? Do you know
> of one which does that?
>
A relocating bootloader is one that doesn't load the kernel at
CONFIG_PHYSICAL_ADDRESS. The EFI stub is one example.
__START_KERNEL_map is not relocated. On x86-64 we do relocation by
pointing the page tables at a different address.
So I really think we need this to be a leaq, so we take a nonstandard
load address into consideration.
-hpa
next prev parent reply other threads:[~2016-03-02 21:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 11:20 [RFC PATCH] x86: Make sure verify_cpu has a good stack Borislav Petkov
2016-03-02 15:55 ` Mika Penttilä
2016-03-02 16:15 ` Borislav Petkov
2016-03-02 16:38 ` Mika Penttilä
2016-03-02 16:55 ` Borislav Petkov
2016-03-02 17:44 ` Mika Penttilä
2016-03-02 16:22 ` Brian Gerst
2016-03-02 16:25 ` Borislav Petkov
2016-03-02 17:53 ` H. Peter Anvin
2016-03-02 18:15 ` Borislav Petkov
2016-03-02 18:25 ` H. Peter Anvin
2016-03-02 18:39 ` H. Peter Anvin
2016-03-02 19:50 ` Borislav Petkov
2016-03-02 20:46 ` Borislav Petkov
2016-03-02 21:35 ` H. Peter Anvin
2016-03-02 21:46 ` Borislav Petkov
2016-03-02 21:54 ` H. Peter Anvin [this message]
2016-03-02 22:09 ` Borislav Petkov
2016-03-02 22:11 ` H. Peter Anvin
2016-03-02 22:28 ` Borislav Petkov
2016-03-02 22:32 ` H. Peter Anvin
2016-03-02 22:40 ` Borislav Petkov
2016-03-03 0:13 ` Yinghai Lu
2016-03-03 1:00 ` Yinghai Lu
2016-03-03 2:50 ` Yinghai Lu
2016-03-03 12:28 ` Borislav Petkov
2016-03-03 15:26 ` H. Peter Anvin
2016-03-03 16:29 ` Borislav Petkov
2016-03-03 20:22 ` H. Peter Anvin
2016-03-03 20:54 ` Borislav Petkov
2016-03-03 21:22 ` H. Peter Anvin
2016-03-03 21:38 ` Borislav Petkov
2016-03-04 1:18 ` Yinghai Lu
2016-03-04 2:25 ` Yinghai Lu
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