[PATCH 0/2] arm64: mm: use fully constructed struct pages from EFI page tables

[Laura Abbott]

On 07/22/2016 10:32 AM, Ard Biesheuvel wrote:
> As reported by Sudeep, the EFI memory attributes table handling may crash
> on an uninitialized spinlock in the struct page associated with a UEFI runtime
> translation table page.
>
> This is caused by a failure to take into account the fact that generic code
> treats such pages differently depending on whether they are associated with
> init_mm or not. The EFI page tables are completely separate from both the
> kernel and the userland mappings, and are completely static during the
> lifetime of the OS, but still, the most robust solution is to simply
> construct these pages fully, so that generic code that compares against
> &init_mm can work safely and correctly.
>
> Patch #1 is a preparatory patch to drop a reference to late_pgtable_alloc
> from code that no longer needs it.
>
> Patch #2 renamed late_pgtable_alloc to pgd_table_alloc, and updates it to
> construct the struct page associated with the allocated page.
>
> Ard Biesheuvel (2):
>   arm64: mm: make create_mapping_late() non-allocating
>   arm64: mm: run pgtable_page_ctor() on non-swapper translation table
>     pages
>
>  arch/arm64/mm/mmu.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>

Reviewed-by: Laura Abbott <labbott at redhat.com>