Re: [PATCHv3 2/5] x86/boot/compressed/64: Print error if 5-level paging is not supported

[Borislav Petkov]

On Mon, Dec 04, 2017 at 03:40:56PM +0300, Kirill A. Shutemov wrote:
> We cannot proceed booting if the machine doesn't support the paging mode
> kernel was compiled for.
> 
> Getting error the usual way -- via validate_cpu() -- is not going to
> work. We need to enable appropriate paging mode before that, otherwise
> kernel would triple-fault during KASLR setup.
> 
> This code will go away once we get support for boot-time switching
> between paging modes.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>	[4.14+]
> ---
>  arch/x86/boot/compressed/misc.c       | 16 ++++++++++++++++
>  arch/x86/boot/compressed/pgtable_64.c |  2 +-
>  2 files changed, 17 insertions(+), 1 deletion(-)

Reported-and-tested-by: Borislav Petkov <bp@xxxxxxx>

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
--