Re: [PATCH v8 0/3] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory

Chao Fan
2018-10-11T01:30:16Z

On Wed, Oct 10, 2018 at 07:16:16PM +0200, Borislav Petkov wrote:
>On Wed, Oct 10, 2018 at 04:41:16PM +0800, Chao Fan wrote:
>> In the earliest time, I tried to dig ACPI tabls to solve this problem.
>> But I didn't splite the code in 'compressed/' and ACPI code, so the patch
>> is hard to follow so refused by community.
>> Somebody suggest to add a kernel parameter to specify the
>> immovable memory so that limit kaslr in these regions. Then I make
>> a new patchset. After several versions, Ingo gave a suggestion:
>> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1634024.html
>> Follow Ingo's suggestion, imitate the ACPI code to parse the acpi
>> tables, so that the kaslr can get necessary memory information in
>> ACPI tables.
>> I think ACPI code is an independent part, so copy the codes
>> and functions to 'compressed/' directory, so that kaslr won't
>> influence the initialization of ACPI.
>
>You say "copy". I'm still about to look at the code but can those
>functions be carved out in a separate compilation unit which ACPI *and*
>KASLR can both link with so that there's no duplication?

Sorry for my poor English, I used 'copy' but they are not same.
Maybe 'imitate' is better.
Just like I said in my log, The ACPI part need to handle the map
between physical address and virtual address.
But in KASLR part, I remove these operations.
So my code is simplified version.

Thanks,
Chao Fan

>
>--
>Regards/Gruss,
> Boris.
>
>Good mailing practices for 400: avoid top-posting and trim the reply.
>
>