[PATCH v4 06/14] nios2: add support for folded p4d page tables

[Mike Rapoport]

From: Mike Rapoport <r...@linux.ibm.com>

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 <r...@linux.ibm.com>
---
 arch/nios2/include/asm/pgtable.h | 3 +--
 arch/nios2/mm/fault.c            | 9 +++++++--
 arch/nios2/mm/ioremap.c          | 6 +++++-
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index f98b7f4519ba..47a1a3ea5734 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -22,7 +22,6 @@
 #include <asm/tlbflush.h>
 
 #include <asm/pgtable-bits.h>
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopmd.h>
 
 #define FIRST_USER_ADDRESS     0UL
@@ -100,7 +99,7 @@ extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];
  */
 static inline void set_pmd(pmd_t *pmdptr, pmd_t pmdval)
 {
-       pmdptr->pud.pgd.pgd = pmdval.pud.pgd.pgd;
+       *pmdptr = pmdval;
 }
 
 /* to find an entry in a page-table-directory */
diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c
index ec9d8a9c426f..964eac1a21d0 100644
--- a/arch/nios2/mm/fault.c
+++ b/arch/nios2/mm/fault.c
@@ -242,6 +242,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, 
unsigned long cause,
                 */
                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;
@@ -253,8 +254,12 @@ asmlinkage void do_page_fault(struct pt_regs *regs, 
unsigned long cause,
                        goto no_context;
                set_pgd(pgd, *pgd_k);
 
-               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;
                pmd = pmd_offset(pud, address);
diff --git a/arch/nios2/mm/ioremap.c b/arch/nios2/mm/ioremap.c
index 819bdfcc2e71..fe821efb9a99 100644
--- a/arch/nios2/mm/ioremap.c
+++ b/arch/nios2/mm/ioremap.c
@@ -86,11 +86,15 @@ static int remap_area_pages(unsigned long address, unsigned 
long phys_addr,
        if (address >= end)
                BUG();
        do {
+               p4d_t *p4d;
                pud_t *pud;
                pmd_t *pmd;
 
                error = -ENOMEM;
-               pud = pud_alloc(&init_mm, dir, address);
+               p4d = p4d_alloc(&init_mm, dir, address);
+               if (!p4d)
+                       break;
+               pud = pud_alloc(&init_mm, p4d, address);
                if (!pud)
                        break;
                pmd = pmd_alloc(&init_mm, pud, address);
-- 
2.25.1

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