xtensa: switch to generic version of pte allocation

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.

[jcmvbkbc@gmail.com: xtensa: fix closing endif comment]
Link: http://lkml.kernel.org/r/20200721024751.1257-1-jcmvbkbc@gmail.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/xtensa/include/asm/pgalloc.h b/arch/xtensa/include/asm/pgalloc.h
index 1d38f0e755ba965d61caae06f6c0a89c277f6c20..5553abed69330d34a449be7b2fb7d3dbece1efed 100644 (file)
--- 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 */