From 07037db5d479f90377c998259a4f9a469c404edf Mon Sep 17 00:00:00 2001
From: Palmer Dabbelt <palmer@dabbelt.com>
Date: Mon, 10 Jul 2017 18:06:09 -0700
Subject: RISC-V: Paging and MMU

This patch contains code to manage the RISC-V MMU, including definitions
of the page tables and the page walking code.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
---
 arch/riscv/include/asm/pgalloc.h | 124 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 arch/riscv/include/asm/pgalloc.h

(limited to 'arch/riscv/include/asm/pgalloc.h')

diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
new file mode 100644
index 000000000000..a79ed5faff3a
--- /dev/null
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com>
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#ifndef _ASM_RISCV_PGALLOC_H
+#define _ASM_RISCV_PGALLOC_H
+
+#include <linux/mm.h>
+#include <asm/tlb.h>
+
+static inline void pmd_populate_kernel(struct mm_struct *mm,
+	pmd_t *pmd, pte_t *pte)
+{
+	unsigned long pfn = virt_to_pfn(pte);
+
+	set_pmd(pmd, __pmd((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
+}
+
+static inline void pmd_populate(struct mm_struct *mm,
+	pmd_t *pmd, pgtable_t pte)
+{
+	unsigned long pfn = virt_to_pfn(page_address(pte));
+
+	set_pmd(pmd, __pmd((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
+}
+
+#ifndef __PAGETABLE_PMD_FOLDED
+static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
+{
+	unsigned long pfn = virt_to_pfn(pmd);
+
+	set_pud(pud, __pud((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
+}
+#endif /* __PAGETABLE_PMD_FOLDED */
+
+#define pmd_pgtable(pmd)	pmd_page(pmd)
+
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	pgd_t *pgd;
+
+	pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
+	if (likely(pgd != NULL)) {
+		memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
+		/* Copy kernel mappings */
+		memcpy(pgd + USER_PTRS_PER_PGD,
+			init_mm.pgd + USER_PTRS_PER_PGD,
+			(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+	}
+	return pgd;
+}
+
+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+	free_page((unsigned long)pgd);
+}
+
+#ifndef __PAGETABLE_PMD_FOLDED
+
+static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+	return (pmd_t *)__get_free_page(
+		GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
+}
+
+static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
+{
+	free_page((unsigned long)pmd);
+}
+
+#define __pmd_free_tlb(tlb, pmd, addr)  pmd_free((tlb)->mm, pmd)
+
+#endif /* __PAGETABLE_PMD_FOLDED */
+
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
+	unsigned long address)
+{
+	return (pte_t *)__get_free_page(
+		GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
+}
+
+static inline struct page *pte_alloc_one(struct mm_struct *mm,
+	unsigned long address)
+{
+	struct page *pte;
+
+	pte = alloc_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
+	if (likely(pte != NULL))
+		pgtable_page_ctor(pte);
+	return pte;
+}
+
+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_page_dtor(pte);
+	__free_page(pte);
+}
+
+#define __pte_free_tlb(tlb, pte, buf)   \
+do {                                    \
+	pgtable_page_dtor(pte);         \
+	tlb_remove_page((tlb), pte);    \
+} while (0)
+
+static inline void check_pgt_cache(void)
+{
+}
+
+#endif /* _ASM_RISCV_PGALLOC_H */
-- 
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