Re: [PATCH V2] x86/efi: Add EFI_PGT_DUMP support for x86_32, kexec

From: Matt Fleming
Date: Mon May 15 2017 - 10:27:42 EST


On Thu, 11 May, at 12:20:33PM, Sai Praneeth Prakhya wrote:
> From: Sai Praneeth <sai.praneeth.prakhya@xxxxxxxxx>
>
> EFI_PGT_DUMP, as the name suggests dumps efi page tables to dmesg during
> kernel boot. This feature is very useful while debugging page
> faults/null pointer dereferences to efi related addresses. Presently,
> this feature is limited only to x86_64, so let's extend it to other efi
> configurations like kexec kernel, efi=old_map and to x86_32 as well.
> This doesn't effect normal boot path because this config option should
> be used only for debug purposes.
>
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Ricardo Neri <ricardo.neri@xxxxxxxxx>
> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx>
>
> Changes since v1:
> 1. Call efi_dump_pagetable() only once from efi_enter_virtual_mode() -
> as suggested by Boris
>
> ---
> arch/x86/platform/efi/efi.c | 3 ++-
> arch/x86/platform/efi/efi_32.c | 9 ++++++++-
> arch/x86/platform/efi/efi_64.c | 5 ++++-
> 3 files changed, 14 insertions(+), 3 deletions(-)

Thanks Sai, applied.