linux-kernel - Re: [PATCH v9 3/8] x86/boot: Add efi_get_rsdp

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Date:   Thu, 18 Oct 2018 13:54:03 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Baoquan He <bhe@...hat.com>
CC:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <linux-efi@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
        <bp@...en8.de>, <tglx@...utronix.de>, <mingo@...hat.com>,
        <hpa@...or.com>, <keescook@...omium.org>, <msys.mizuma@...il.com>,
        <indou.takao@...fujitsu.com>, <caoj.fnst@...fujitsu.com>
Subject: Re: [PATCH v9 3/8] x86/boot: Add efi_get_rsdp_addr() to dig out RSDP
 from EFI table

On Thu, Oct 18, 2018 at 12:35:39PM +0800, Baoquan He wrote:
>On 10/17/18 at 06:20pm, Chao Fan wrote:
>> There is a bug that kaslr may randomly choose some positions
>> which are located in movable memory regions. This will break memory
>> hotplug feature and make the movable memory chosen by KASLR can't be
>> removed. So dig SRAT table from ACPI tables to get memory information.
>
>This patch is only adding a function efi_get_rsdp_addr() which will be
>used in later patch. Do we need to describe bug here?

Yes, it's the first mail of this serial, so I add more log.
>
>Can we focus on what is this function, and why it's written like that,
>and why it's here?

Sure.
I am just afraid lack of log.

Thanks,
Chao Fan

>> 
>> Imitate the ACPI code of parsing ACPI tables to dig and read ACPI
>> tables. Since some operations are not needed here, functions are
>> simplified. Functions will be used to dig only SRAT tables to get
>> information of memory, so that KASLR can the memory in immovable node.
>> 
>
>