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-rw-r--r--arch/arc/include/asm/pgalloc.h134
1 files changed, 134 insertions, 0 deletions
diff --git a/arch/arc/include/asm/pgalloc.h b/arch/arc/include/asm/pgalloc.h
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+++ b/arch/arc/include/asm/pgalloc.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * vineetg: June 2011
+ * -"/proc/meminfo | grep PageTables" kept on increasing
+ * Recently added pgtable dtor was not getting called.
+ *
+ * vineetg: May 2011
+ * -Variable pg-sz means that Page Tables could be variable sized themselves
+ * So calculate it based on addr traversal split [pgd-bits:pte-bits:xxx]
+ * -Page Table size capped to max 1 to save memory - hence verified.
+ * -Since these deal with constants, gcc compile-time optimizes them.
+ *
+ * vineetg: Nov 2010
+ * -Added pgtable ctor/dtor used for pgtable mem accounting
+ *
+ * vineetg: April 2010
+ * -Switched pgtable_t from being struct page * to unsigned long
+ * =Needed so that Page Table allocator (pte_alloc_one) is not forced to
+ * deal with struct page. That way in future we can make it allocate
+ * multiple PG Tbls in one Page Frame
+ * =sweet side effect is avoiding calls to ugly page_address( ) from the
+ * pg-tlb allocator sub-sys (pte_alloc_one, ptr_free, pmd_populate)
+ *
+ * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
+ */
+
+#ifndef _ASM_ARC_PGALLOC_H
+#define _ASM_ARC_PGALLOC_H
+
+#include <linux/mm.h>
+#include <linux/log2.h>
+
+static inline void
+pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
+{
+ pmd_set(pmd, pte);
+}
+
+static inline void
+pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
+{
+ pmd_set(pmd, (pte_t *) ptep);
+}
+
+static inline int __get_order_pgd(void)
+{
+ return get_order(PTRS_PER_PGD * sizeof(pgd_t));
+}
+
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ int num, num2;
+ pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd());
+
+ if (ret) {
+ num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
+ memzero(ret, num * sizeof(pgd_t));
+
+ num2 = VMALLOC_SIZE / PGDIR_SIZE;
+ memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t));
+
+ memzero(ret + num + num2,
+ (PTRS_PER_PGD - num - num2) * sizeof(pgd_t));
+
+ }
+ return ret;
+}
+
+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+ free_pages((unsigned long)pgd, __get_order_pgd());
+}
+
+
+/*
+ * With software-only page-tables, addr-split for traversal is tweakable and
+ * that directly governs how big tables would be at each level.
+ * Further, the MMU page size is configurable.
+ * Thus we need to programatically assert the size constraint
+ * All of this is const math, allowing gcc to do constant folding/propagation.
+ */
+
+static inline int __get_order_pte(void)
+{
+ return get_order(PTRS_PER_PTE * sizeof(pte_t));
+}
+
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
+{
+ pte_t *pte;
+
+ pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ __get_order_pte());
+
+ return pte;
+}
+
+static inline pgtable_t
+pte_alloc_one(struct mm_struct *mm)
+{
+ pgtable_t pte_pg;
+ struct page *page;
+
+ pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL, __get_order_pte());
+ if (!pte_pg)
+ return 0;
+ memzero((void *)pte_pg, PTRS_PER_PTE * sizeof(pte_t));
+ page = virt_to_page(pte_pg);
+ if (!pgtable_pte_page_ctor(page)) {
+ __free_page(page);
+ return 0;
+ }
+
+ return pte_pg;
+}
+
+static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
+{
+ free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */
+}
+
+static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
+{
+ pgtable_pte_page_dtor(virt_to_page(ptep));
+ free_pages((unsigned long)ptep, __get_order_pte());
+}
+
+#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte)
+
+#define pmd_pgtable(pmd) ((pgtable_t) pmd_page_vaddr(pmd))
+
+#endif /* _ASM_ARC_PGALLOC_H */