Re: [PATCH] x86/boot: Use EFI setup data if provided

Borislav Petkov
2019-03-25T07:53:51Z

On Mon, Mar 25, 2019 at 03:27:10PM +0800, Baoquan He wrote:
> Kexec kernel also need to get rsdp to get SRAT tables so that KASLR can
> avoid those hotpluggable regions in boot compression stage.
>
> The kexec_file_load has filled in acpi_rsdp_addr of kexec kernel in
> below code. It will return direclty in get_rsdp_addr() since
> acpi_rsdp_addr is got from boot_params->acpi_rsdp_addr.
>
> arch/x86/kernel/kexec-bzimage64.c <<setup_boot_parameters>>
> params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;
>
> The other interface, kexec_load, its boot_params filling is done in user
> space kexec_tools. And we haven't made the acpi_rsdp_addr filling yet.
> And the old kexec_tools utility can also cause the new kexec kernel to
> search efi rspd pointer even thought it's fixed.

Yes, kexec is a pile of ugly and fragile hackery.

--
Regards/Gruss,
Boris.

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