[PATCH 3/8] xtensa: switch to generic version of pte allocation

Mike Rapoport
2020-06-27T14:35:38Z

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

xtensa clears PTEs during allocation of the page tables and pte_clear()
sets the PTE to a non-zero value. Splitting ptes_clear() helper out of
pte_alloc_one() and pte_alloc_one_kernel() allows reuse of base generic
allocation methods (__pte_alloc_one() and __pte_alloc_one_kernel()) and the
common GFP mask for page table allocations.

The pte_free() and pte_free_kernel() implementations on xtensa are
identical to the generic ones and can be dropped.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
arch/xtensa/include/asm/pgalloc.h | 41 ++++++++++++++-----------------
1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/arch/xtensa/include/asm/pgalloc.h b/arch/xtensa/include/asm/pgalloc.h
index 1d38f0e755ba..60ee94b42850 100644
--- a/arch/xtensa/include/asm/pgalloc.h
+++ b/arch/xtensa/include/asm/pgalloc.h
@@ -8,9 +8,14 @@
#ifndef _XTENSA_PGALLOC_H
#define _XTENSA_PGALLOC_H

+#ifdef CONFIG_MMU
#include <linux/highmem.h>
#include <linux/slab.h>

+#define __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
+#define __HAVE_ARCH_PTE_ALLOC_ONE
+#include <asm-generic/pgalloc.h>
+
/*
* Allocating and freeing a pmd is trivial: the 1-entry pmd is
* inside the pgd, so has no extra memory associated with it.
@@ -33,45 +38,37 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
free_page((unsigned long)pgd);
}

+static inline void ptes_clear(pte_t *ptep)
+{
+ int i;
+
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ pte_clear(NULL, 0, ptep + i);
+}
+
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
{
pte_t *ptep;
- int i;

- ptep = (pte_t *)__get_free_page(GFP_KERNEL);
+ ptep = (pte_t *)__pte_alloc_one_kernel(mm);
if (!ptep)
return NULL;
- for (i = 0; i < 1024; i++)
- pte_clear(NULL, 0, ptep + i);
+ ptes_clear(ptep);
return ptep;
}

static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
{
- pte_t *pte;
struct page *page;

- pte = pte_alloc_one_kernel(mm);
- if (!pte)
- return NULL;
- page = virt_to_page(pte);
- if (!pgtable_pte_page_ctor(page)) {
- __free_page(page);
+ page = __pte_alloc_one(mm, GFP_PGTABLE_USER);
+ if (!page)
return NULL;
- }
+ ptes_clear(page_address(page));
return page;
}

-static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
-{
- free_page((unsigned long)pte);
-}
-
-static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
-{
- pgtable_pte_page_dtor(pte);
- __free_page(pte);
-}
#define pmd_pgtable(pmd) pmd_page(pmd)
+#endif CONFIG_MMU

#endif /* _XTENSA_PGALLOC_H */
--
2.26.2