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From:   Matthew Garrett <mjg59@google.com>
Date:   Wed, 14 Aug 2019 11:02:32 -0700
Message-ID: <CACdnJutcF6ZdQKwz7L+i9FUuD8SBsHuhk8rwQpwfDsCpM1y9dA@mail.gmail.com>
Subject: Re: [PATCH V38 15/29] acpi: Ignore acpi_rsdp kernel param when the
 kernel has been locked down
To:     Borislav Petkov <bp@alien8.de>
Cc:     James Morris <jmorris@namei.org>,
        LSM List <linux-security-module@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Josh Boyer <jwboyer@redhat.com>,
        David Howells <dhowells@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Dave Young <dyoung@redhat.com>, linux-acpi@vger.kernel.org
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On Wed, Aug 14, 2019 at 10:46 AM Borislav Petkov <bp@alien8.de> wrote:
> Yeah, ok, I see what you're doing there. AFAICT, you do that in
>
> setup_arch->acpi_boot_table_init-> ... -> acpi_os_get_root_pointer()

Right.

> I hope nothing needs it earlier because then we'll have to restructure
> again...

Passing the RSDP via command line is a pretty grotesque hack - we
should just set up boot params in kexec_file, which would leave this
as a problem for legacy kexec and nothing else.