Commit-ID:  cfe19577047e74cdac5826adbdc2337d8437f8fb
Gitweb:     https://git.kernel.org/tip/cfe19577047e74cdac5826adbdc2337d8437f8fb
Author:     Kirill A. Shutemov <[email protected]>
AuthorDate: Mon, 25 Jun 2018 15:08:52 +0300
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 27 Jun 2018 09:52:52 +0200

x86/efi: Fix efi_call_phys_epilog() with CONFIG_X86_5LEVEL=y

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]>
---
 arch/x86/platform/efi/efi_64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index e01f7ceb9e7a..77873ce700ae 100644
--- 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 *save_pgd)
                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);

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