[PATCH v3 06/14] openrisc: add support for folded p4d page tables

Mike Rapoport
2020-02-27T08:46:00Z

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

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
arch/openrisc/include/asm/pgtable.h | 1 -
arch/openrisc/mm/fault.c | 10 ++++++++--
arch/openrisc/mm/init.c | 4 +++-
3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index 248d22d8faa7..c072943fc721 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -21,7 +21,6 @@
#ifndef __ASM_OPENRISC_PGTABLE_H
#define __ASM_OPENRISC_PGTABLE_H

-#define __ARCH_USE_5LEVEL_HACK
#include <asm-generic/pgtable-nopmd.h>

#ifndef __ASSEMBLY__
diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c
index 5d4d3a9691d0..44aa04545de3 100644
--- a/arch/openrisc/mm/fault.c
+++ b/arch/openrisc/mm/fault.c
@@ -296,6 +296,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address,

int offset = pgd_index(address);
pgd_t *pgd, *pgd_k;
+ p4d_t *p4d, *p4d_k;
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pte_t *pte_k;
@@ -322,8 +323,13 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address,
* it exists.
*/

- pud = pud_offset(pgd, address);
- pud_k = pud_offset(pgd_k, address);
+ p4d = p4d_offset(pgd, address);
+ p4d_k = p4d_offset(pgd_k, address);
+ if (!p4d_present(*p4d_k))
+ goto no_context;
+
+ pud = pud_offset(p4d, address);
+ pud_k = pud_offset(p4d_k, address);
if (!pud_present(*pud_k))
goto no_context;

diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
index 1f87b524db78..2536aeae0975 100644
--- a/arch/openrisc/mm/init.c
+++ b/arch/openrisc/mm/init.c
@@ -71,6 +71,7 @@ static void __init map_ram(void)
unsigned long v, p, e;
pgprot_t prot;
pgd_t *pge;
+ p4d_t *p4e;
pud_t *pue;
pmd_t *pme;
pte_t *pte;
@@ -90,7 +91,8 @@ static void __init map_ram(void)

while (p < e) {
int j;
- pue = pud_offset(pge, v);
+ p4e = p4d_offset(pge, v);
+ pue = pud_offset(p4e, v);
pme = pmd_offset(pue, v);

if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
--
2.24.0