arm: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, and remove __ARCH_USE_5LEVEL_HACK.

[[email protected]: fix kexec]
  Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Brian Cain <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: James Morse <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Julien Thierry <[email protected]>
Cc: Ley Foon Tan <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Russell King <[email protected]>
Cc: Stafford Horne <[email protected]>
Cc: Stefan Kristiansson <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index ae857f41f68d..489aaafa6ebd 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -91,6 +91,7 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
 {
 	spinlock_t *ptl;
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
@@ -100,7 +101,11 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
 	if (pgd_none_or_clear_bad(pgd))
 		return 0;
 
-	pud = pud_offset(pgd, address);
+	p4d = p4d_offset(pgd, address);
+	if (p4d_none_or_clear_bad(p4d))
+		return 0;
+
+	pud = pud_offset(p4d, address);
 	if (pud_none_or_clear_bad(pud))
 		return 0;