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

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Message-ID: <20181018043539.GF1885@192.168.1.4>
Date:   Thu, 18 Oct 2018 12:35:39 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Chao Fan <fanc.fnst@...fujitsu.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 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?

Can we focus on what is this function, and why it's written like that,
and why it's here?
> 
> 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.
>