Re: [PATCH] x86/efi: Setup separate EFI page tables in kexec paths

[Srikar Dronamraju <srikar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

* Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> [2016-01-21 14:11:59]:

> The switch to using a new dedicated page table for EFI runtime calls
> in commit commit 67a9108ed431 ("x86/efi: Build our own page table
> structures") failed to take into account changes required for the
> kexec code paths, which are unfortunately duplicated in the EFI code.
> 
> Call the allocation and setup functions in kexec_enter_virtual_mode()
> just like we do for __efi_enter_virtual_mode() to avoid hitting
> NULL-pointer dereferences when making EFI runtime calls.
> 
> At the very least, the call to efi_setup_page_tables() should have
> existed for kexec before commit 67a9108ed431. Things just magically
> worked because we were actually using the kernel's page tables that
> contained the required mappings.
> 
> Reported-by: Srikar Dronamraju <srikar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Cc: Raghavendra K T <raghavendra.kt-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Cc: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
> Cc: Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>
> Signed-off-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>

Applied this patch on top of tip/x86/efi and was able to build and boot
the kernel.

-- 
Thanks and Regards
Srikar Dronamraju