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SubjectRe: [PATCH] x86/efi: Add EFI_PGT_DUMP support for x86_32, kexec and efi=old_map
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On Thu, 2017-05-11 at 13:18 +0200, Borislav Petkov wrote:
> On Wed, May 10, 2017 at 03:49:05PM -0700, Sai Praneeth Prakhya wrote:
> > From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
> >
> > 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@intel.com>
> > Cc: Borislav Petkov <bp@alien8.de>
> > Cc: Ricardo Neri <ricardo.neri@intel.com>
> > Cc: Matt Fleming <matt@codeblueprint.co.uk>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> > ---
> > arch/x86/platform/efi/efi.c | 2 ++
> > arch/x86/platform/efi/efi_32.c | 9 ++++++++-
> > arch/x86/platform/efi/efi_64.c | 5 ++++-
> > 3 files changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> > index 217dc166c649..a6d6cd8fe78a 100644
> > --- a/arch/x86/platform/efi/efi.c
> > +++ b/arch/x86/platform/efi/efi.c
> > @@ -890,6 +890,8 @@ static void __init kexec_enter_virtual_mode(void)
> > if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
> > runtime_code_page_mkexec();
> >
> > + efi_dump_pagetable();
>
> You can call that only once at the end of efi_enter_virtual_mode()
> instead of adding it here and leaving it in __efi_enter_virtual_mode().
>

Thanks for the suggestion Boris,
Sure! will roll out v2 with this change

Regards,
Sai

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