linux-kernel - Re: [PATCH v2 2/2] x86, kexec_file_load: make it work with efi=noruntime or efi=old

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Date:   Mon, 21 Jan 2019 09:29:32 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Chao Fan <fanc.fnst@...fujitsu.com>
Cc:     Kairui Song <kasong@...hat.com>, linux-kernel@...r.kernel.org,
        tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, Dave Young <dyoung@...hat.com>,
        Baoquan He <bhe@...hat.com>, kexec@...ts.infradead.org,
        akpm@...ux-foundation.org, robert.moore@...el.com,
        erik.schmauss@...el.com, rafael.j.wysocki@...el.com,
        Len Brown <lenb@...nel.org>
Subject: Re: [PATCH v2 2/2] x86, kexec_file_load: make it work with
 efi=noruntime or efi=old_map

On Mon, Jan 21, 2019 at 09:18:30AM +0800, Chao Fan wrote:
> So I have changed as this method and put in my mail thread, you may not
> notice, so I put here for my function if I need to fill the
> boot_parameters:
> 
> static inline acpi_physical_address get_boot_params_rsdp(void)
> {
>         return boot_params->acpi_rsdp_addr;
> }

Why do you need that silly wrapper?

> static acpi_physical_address get_rsdp_addr(void)
> {
>         bool boot_params_rsdp_exist;

What's that bool supposed to do?

>         acpi_physical_address pa;
> 
>         pa = get_acpi_rsdp();
> 
>         if (!pa)
>                 pa = get_boot_params_rsdp();
> 
>         if (!pa) {
>                 pa = efi_get_rsdp_addr();
>                 boot_params_rsdp_exist = false;
>         }
>         else
>                 boot_params_rsdp_exist = true;
> 
>         if (!pa)
>                 pa = bios_get_rsdp_addr();
> 
>         if (pa && !boot_params_rsdp_exist)
>                 boot_params.acpi_rsdp_addr = pa;
> 
>         return pa;
> }
> 
> At the same time, I notice kernel only parses it when
> "#ifdef CONFIG_ACPI", we should keep sync with kernel, but I think
> we are parsing SRAT, CONFIG_ACPI is needed sure, so I am going to
> update the define of EARLY_SRAT_PARSE:
> 
> config EARLY_SRAT_PARSE
>         bool "EARLY SRAT parsing"
>         def_bool y
>         depends on RANDOMIZE_BASE && MEMORY_HOTREMOVE && ACPI

Actually, you don't need that anymore - make it unconditionally
built-in. Because there are a bunch of users which need this and instead
of complicating this config option with a bunch of dependencies, we can
just as well have it always on.

Thx.

-- 
Regards/Gruss,
    Boris.

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