4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Kirill A. Shutemov <[email protected]> commit cfe19577047e74cdac5826adbdc2337d8437f8fb upstream. Open-coded page table entry checks don't work correctly when we fold the page table level at runtime. pgd_present() on 4-level paging machine always returns true, but open-coded version of the check may return false-negative result and we silently skip the rest of the loop body in efi_call_phys_epilog(). Replace open-coded checks with proper helpers. Signed-off-by: Kirill A. Shutemov <[email protected]> Acked-by: Ard Biesheuvel <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Baoquan He <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Matt Fleming <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] # v4.12+ Fixes: 94133e46a0f5 ("x86/efi: Correct EFI identity mapping under 'efi=old_map' when KASLR is enabled") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/platform/efi/efi_64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -166,14 +166,14 @@ void __init efi_call_phys_epilog(pgd_t * pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE); set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]); - if (!(pgd_val(*pgd) & _PAGE_PRESENT)) + if (!pgd_present(*pgd)) continue; for (i = 0; i < PTRS_PER_P4D; i++) { p4d = p4d_offset(pgd, pgd_idx * PGDIR_SIZE + i * P4D_SIZE); - if (!(p4d_val(*p4d) & _PAGE_PRESENT)) + if (!p4d_present(*p4d)) continue; pud = (pud_t *)p4d_page_vaddr(*p4d);
