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-rw-r--r--arch/arm64/include/asm/kernel-pgtable.h83
1 files changed, 83 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
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+++ b/arch/arm64/include/asm/kernel-pgtable.h
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+/*
+ * Kernel page table mapping
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_KERNEL_PGTABLE_H
+#define __ASM_KERNEL_PGTABLE_H
+
+
+/*
+ * The linear mapping and the start of memory are both 2M aligned (per
+ * the arm64 booting.txt requirements). Hence we can use section mapping
+ * with 4K (section size = 2M) but not with 16K (section size = 32M) or
+ * 64K (section size = 512M).
+ */
+#ifdef CONFIG_ARM64_4K_PAGES
+#define ARM64_SWAPPER_USES_SECTION_MAPS 1
+#else
+#define ARM64_SWAPPER_USES_SECTION_MAPS 0
+#endif
+
+/*
+ * The idmap and swapper page tables need some space reserved in the kernel
+ * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
+ * map the kernel. With the 64K page configuration, swapper and idmap need to
+ * map to pte level. The swapper also maps the FDT (see __create_page_tables
+ * for more information). Note that the number of ID map translation levels
+ * could be increased on the fly if system RAM is out of reach for the default
+ * VA range, so pages required to map highest possible PA are reserved in all
+ * cases.
+ */
+#if ARM64_SWAPPER_USES_SECTION_MAPS
+#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
+#define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1)
+#else
+#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
+#define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT))
+#endif
+
+#define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
+#define IDMAP_DIR_SIZE (IDMAP_PGTABLE_LEVELS * PAGE_SIZE)
+
+/* Initial memory map size */
+#if ARM64_SWAPPER_USES_SECTION_MAPS
+#define SWAPPER_BLOCK_SHIFT SECTION_SHIFT
+#define SWAPPER_BLOCK_SIZE SECTION_SIZE
+#define SWAPPER_TABLE_SHIFT PUD_SHIFT
+#else
+#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
+#define SWAPPER_BLOCK_SIZE PAGE_SIZE
+#define SWAPPER_TABLE_SHIFT PMD_SHIFT
+#endif
+
+/* The size of the initial kernel direct mapping */
+#define SWAPPER_INIT_MAP_SIZE (_AC(1, UL) << SWAPPER_TABLE_SHIFT)
+
+/*
+ * Initial memory map attributes.
+ */
+#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
+#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
+
+#if ARM64_SWAPPER_USES_SECTION_MAPS
+#define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
+#else
+#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
+#endif
+
+
+#endif /* __ASM_KERNEL_PGTABLE_H */