Re: Cannot load linux after recent efi-related changes

From: Mike Krinkin
Date: Sat Sep 17 2016 - 21:15:10 EST

On Sat, Sep 17, 2016 at 07:23:57PM +0300, Mike Krinkin wrote:
> Hello,
> after commit 3dad6f7f6975 ("x86/efi: Defer efi_esrt_init until after
> memblock_x86_fill") kernel hits BUG_ON __efi_enter_virtual_mode because
> efi.systab is NULL. With older kernel versions i face the problem with
> efi_mem_reserve described in the commit.
> AFAICS, get_systab_virt_addr called from efi_map_regions should set
> efi.systab, but i dumped memory desciptors in efi_map_regions and
> apparently none of them describes region that contains efi_phys.systab,
> so efi.systab remains unset.

I investigated it a bit further, and apparently problem occurs because
efi_esrt_init calls efi_mem_reserve with unaligned range boundaries, and
efi_memmap_insert doesn't handle unaligned ranges properly. The following
fix solves problem for me: