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

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Message-ID: <20190322152328.GD12472@zn.tnic>
Date:   Fri, 22 Mar 2019 16:23:28 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Junichi Nomura <j-nomura@...jp.nec.com>
Cc:     "fanc.fnst@...fujitsu.com" <fanc.fnst@...fujitsu.com>,
        "bp@...e.de" <bp@...e.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH] x86/boot: Use EFI setup data if provided

On Fri, Mar 22, 2019 at 11:03:43AM +0000, Junichi Nomura wrote:
> Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
> boot_params") broke kexec boot on EFI systems.  efi_get_rsdp_addr()
> in the early parsing code tries to search RSDP from EFI table but
> whose address is virtual.
> 
> Since kexec(1) provides physical address of config_table via boot_params,
> efi_get_rsdp_addr() should look for setup_data in the same way as
> efi_systab_init() in arch/x86/platform/efi/efi.c does.

If the kexec kernel should continue to use efi_systab_init() then you
should make efi_get_rsdp_addr() exit early in the kexec-ed kernel.

-- 
Regards/Gruss,
    Boris.

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