We are going to switch core MM to 5-level paging abstraction.
This is preparation step which adds <asm-generic/5level-fixup.h>
As with 4level-fixup.h, the new header allows quickly make all
architectures compatible with 5-level paging in core MM.
In long run we would like to switch architectures to properly folded p4d
level by using <asm-generic/pgtable-nop4d.h>, but it requires more
changes to arch-specific code.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
---
include/asm-generic/4level-fixup.h | 3 ++-
include/asm-generic/5level-fixup.h | 41 ++++++++++++++++++++++++++++++++++++++
include/linux/mm.h | 3 +++
3 files changed, 46 insertions(+), 1 deletion(-)
create mode 100644 include/asm-generic/5level-fixup.h
diff --git a/include/asm-generic/4level-fixup.h b/include/asm-generic/4level-fixup.h
index 5bdab6bffd23..928fd66b1271 100644
--- a/include/asm-generic/4level-fixup.h
+++ b/include/asm-generic/4level-fixup.h
@@ -15,7 +15,6 @@
((unlikely(pgd_none(*(pud))) && __pmd_alloc(mm, pud, address))? \
NULL: pmd_offset(pud, address))
-#define pud_alloc(mm, pgd, address) (pgd)
#define pud_offset(pgd, start) (pgd)
#define pud_none(pud) 0
#define pud_bad(pud) 0
@@ -35,4 +34,6 @@
#undef pud_addr_end
#define pud_addr_end(addr, end) (end)
+#include <asm-generic/5level-fixup.h>
+
#endif
diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
new file mode 100644
index 000000000000..b5ca82dc4175
--- /dev/null
+++ b/include/asm-generic/5level-fixup.h
@@ -0,0 +1,41 @@
+#ifndef _5LEVEL_FIXUP_H
+#define _5LEVEL_FIXUP_H
+
+#define __ARCH_HAS_5LEVEL_HACK
+#define __PAGETABLE_P4D_FOLDED
+
+#define P4D_SHIFT PGDIR_SHIFT
+#define P4D_SIZE PGDIR_SIZE
+#define P4D_MASK PGDIR_MASK
+#define PTRS_PER_P4D 1
+
+#define p4d_t pgd_t
+
+#define pud_alloc(mm, p4d, address) \
+ ((unlikely(pgd_none(*(p4d))) && __pud_alloc(mm, p4d, address)) ? \
+ NULL : pud_offset(p4d, address))
+
+#define p4d_alloc(mm, pgd, address) (pgd)
+#define p4d_offset(pgd, start) (pgd)
+#define p4d_none(p4d) 0
+#define p4d_bad(p4d) 0
+#define p4d_present(p4d) 1
+#define p4d_ERROR(p4d) do { } while (0)
+#define p4d_clear(p4d) pgd_clear(p4d)
+#define p4d_val(p4d) pgd_val(p4d)
+#define p4d_populate(mm, p4d, pud) pgd_populate(mm, p4d, pud)
+#define p4d_page(p4d) pgd_page(p4d)
+#define p4d_page_vaddr(p4d) pgd_page_vaddr(p4d)
+
+#define __p4d(x) __pgd(x)
+#define set_p4d(p4dp, p4d) set_pgd(p4dp, p4d)
+
+#undef p4d_free_tlb
+#define p4d_free_tlb(tlb, x, addr) do { } while (0)
+#define p4d_free(mm, x) do { } while (0)
+#define __p4d_free_tlb(tlb, x, addr) do { } while (0)
+
+#undef p4d_addr_end
+#define p4d_addr_end(addr, end) (end)
+
+#endif
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0d65dd72c0f4..be1fe264eb37 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1619,11 +1619,14 @@ int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
* Remove it when 4level-fixup.h has been removed.
*/
#if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
+
+#ifndef __ARCH_HAS_5LEVEL_HACK
static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
{
return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
NULL: pud_offset(pgd, address);
}
+#endif /* !__ARCH_HAS_5LEVEL_HACK */
static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
{
--
2.11.0
