/* * Based on arch/arm/mm/mmu.c * * Copyright (C) 1995-2005 Russell King * Copyright (C) 2012 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 . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mm.h" /* * Empty_zero_page is a special page that is used for zero-initialized data * and COW. */ struct page *empty_zero_page; EXPORT_SYMBOL(empty_zero_page); pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) { if (!pfn_valid(pfn)) return pgprot_noncached(vma_prot); else if (file->f_flags & O_SYNC) return pgprot_writecombine(vma_prot); return vma_prot; } EXPORT_SYMBOL(phys_mem_access_prot); static void __init *early_alloc(unsigned long sz) { void *ptr = __va(memblock_alloc(sz, sz)); BUG_ON(!ptr); memset(ptr, 0, sz); return ptr; } /* * remap a PMD into pages */ static void split_pmd(pmd_t *pmd, pte_t *pte) { unsigned long pfn = pmd_pfn(*pmd); int i = 0; do { /* * Need to have the least restrictive permissions available * permissions will be fixed up later */ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC)); pfn++; } while (pte++, i++, i < PTRS_PER_PTE); } static void alloc_init_pte(pmd_t *pmd, unsigned long addr, unsigned long end, unsigned long pfn, pgprot_t prot, void *(*alloc)(unsigned long size)) { pte_t *pte; if (pmd_none(*pmd) || pmd_bad(*pmd)) { pte = alloc(PTRS_PER_PTE * sizeof(pte_t)); if (pmd_sect(*pmd)) split_pmd(pmd, pte); __pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE); flush_tlb_all(); } pte = pte_offset_kernel(pmd, addr); do { set_pte(pte, pfn_pte(pfn, prot)); pfn++; } while (pte++, addr += PAGE_SIZE, addr != end); } void split_pud(pud_t *old_pud, pmd_t *pmd) { unsigned long addr = pud_pfn(*old_pud) << PAGE_SHIFT; pgprot_t prot = __pgprot(pud_val(*old_pud) ^ addr); int i = 0; do { set_pmd(pmd, __pmd(addr | prot)); addr += PMD_SIZE; } while (pmd++, i++, i < PTRS_PER_PMD); } static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud, unsigned long addr, unsigned long end, phys_addr_t phys, pgprot_t prot, void *(*alloc)(unsigned long size)) { pmd_t *pmd; unsigned long next; /* * Check for initial section mappings in the pgd/pud and remove them. */ if (pud_none(*pud) || pud_bad(*pud)) { pmd = alloc(PTRS_PER_PMD * sizeof(pmd_t)); if (pud_sect(*pud)) { /* * need to have the 1G of mappings continue to be * present */ split_pud(pud, pmd); } pud_populate(mm, pud, pmd); flush_tlb_all(); } pmd = pmd_offset(pud, addr); do { next = pmd_addr_end(addr, end); /* try section mapping first */ if (((addr | next | phys) & ~SECTION_MASK) == 0) { pmd_t old_pmd =*pmd; set_pmd(pmd, __pmd(phys | pgprot_val(mk_sect_prot(prot)))); /* * Check for previous table entries created during * boot (__create_page_tables) and flush them. */ if (!pmd_none(old_pmd)) flush_tlb_all(); } else { alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys), prot, alloc); } phys += next - addr; } while (pmd++, addr = next, addr != end); } static inline bool use_1G_block(unsigned long addr, unsigned long next, unsigned long phys) { if (PAGE_SHIFT != 12) return false; if (((addr | next | phys) & ~PUD_MASK) != 0) return false; return true; } static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, unsigned long addr, unsigned long end, phys_addr_t phys, pgprot_t prot, void *(*alloc)(unsigned long size)) { pud_t *pud; unsigned long next; if (pgd_none(*pgd)) { pud = alloc(PTRS_PER_PUD * sizeof(pud_t)); pgd_populate(mm, pgd, pud); } BUG_ON(pgd_bad(*pgd)); pud = pud_offset(pgd, addr); do { next = pud_addr_end(addr, end); /* * For 4K granule only, attempt to put down a 1GB block */ if (use_1G_block(addr, next, phys)) { pud_t old_pud = *pud; set_pud(pud, __pud(phys | pgprot_val(mk_sect_prot(prot)))); /* * If we have an old value for a pud, it will * be pointing to a pmd table that we no longer * need (from swapper_pg_dir). * * Look up the old pmd table and free it. */ if (!pud_none(old_pud)) { phys_addr_t table = __pa(pmd_offset(&old_pud, 0)); memblock_free(table, PAGE_SIZE); flush_tlb_all(); } } else { alloc_init_pmd(mm, pud, addr, next, phys, prot, alloc); } phys += next - addr; } while (pud++, addr = next, addr != end); } /* * Create the page directory entries and any necessary page tables for the * mapping specified by 'md'. */ static void __create_mapping(struct mm_struct *mm, pgd_t *pgd, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, void *(*alloc)(unsigned long size)) { unsigned long addr, length, end, next; addr = virt & PAGE_MASK; length = PAGE_ALIGN(size + (virt & ~PAGE_MASK)); end = addr + length; do { next = pgd_addr_end(addr, end); alloc_init_pud(mm, pgd, addr, next, phys, prot, alloc); phys += next - addr; } while (pgd++, addr = next, addr != end); } static void *late_alloc(unsigned long size) { void *ptr; BUG_ON(size > PAGE_SIZE); ptr = (void *)__get_free_page(PGALLOC_GFP); BUG_ON(!ptr); return ptr; } static void __ref create_mapping(phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot) { if (virt < VMALLOC_START) { pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", &phys, virt); return; } __create_mapping(&init_mm, pgd_offset_k(virt & PAGE_MASK), phys, virt, size, prot, early_alloc); } void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot) { __create_mapping(mm, pgd_offset(mm, virt), phys, virt, size, prot, early_alloc); } static void create_mapping_late(phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot) { if (virt < VMALLOC_START) { pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", &phys, virt); return; } return __create_mapping(&init_mm, pgd_offset_k(virt & PAGE_MASK), phys, virt, size, prot, late_alloc); } #ifdef CONFIG_DEBUG_RODATA static void __init __map_memblock(phys_addr_t start, phys_addr_t end) { /* * Set up the executable regions using the existing section mappings * for now. This will get more fine grained later once all memory * is mapped */ unsigned long kernel_x_start = round_down(__pa(_stext), SECTION_SIZE); unsigned long kernel_x_end = round_up(__pa(__init_end), SECTION_SIZE); if (end < kernel_x_start) { create_mapping(start, __phys_to_virt(start), end - start, PAGE_KERNEL); } else if (start >= kernel_x_end) { create_mapping(start, __phys_to_virt(start), end - start, PAGE_KERNEL); } else { if (start < kernel_x_start) create_mapping(start, __phys_to_virt(start), kernel_x_start - start, PAGE_KERNEL); create_mapping(kernel_x_start, __phys_to_virt(kernel_x_start), kernel_x_end - kernel_x_start, PAGE_KERNEL_EXEC); if (kernel_x_end < end) create_mapping(kernel_x_end, __phys_to_virt(kernel_x_end), end - kernel_x_end, PAGE_KERNEL); } } #else static void __init __map_memblock(phys_addr_t start, phys_addr_t end) { create_mapping(start, __phys_to_virt(start), end - start, PAGE_KERNEL_EXEC); } #endif static void __init map_mem(void) { struct memblock_region *reg; phys_addr_t limit; /* * Temporarily limit the memblock range. We need to do this as * create_mapping requires puds, pmds and ptes to be allocated from * memory addressable from the initial direct kernel mapping. * * The initial direct kernel mapping, located at swapper_pg_dir, gives * us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from * PHYS_OFFSET (which must be aligned to 2MB as per * Documentation/arm64/booting.txt). */ if (IS_ENABLED(CONFIG_ARM64_64K_PAGES)) limit = PHYS_OFFSET + PMD_SIZE; else limit = PHYS_OFFSET + PUD_SIZE; memblock_set_current_limit(limit); /* map all the memory banks */ for_each_memblock(memory, reg) { phys_addr_t start = reg->base; phys_addr_t end = start + reg->size; if (start >= end) break; #ifndef CONFIG_ARM64_64K_PAGES /* * For the first memory bank align the start address and * current memblock limit to prevent create_mapping() from * allocating pte page tables from unmapped memory. * When 64K pages are enabled, the pte page table for the * first PGDIR_SIZE is already present in swapper_pg_dir. */ if (start < limit) start = ALIGN(start, PMD_SIZE); if (end < limit) { limit = end & PMD_MASK; memblock_set_current_limit(limit); } #endif __map_memblock(start, end); } /* Limit no longer required. */ memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE); } void __init fixup_executable(void) { #ifdef CONFIG_DEBUG_RODATA /* now that we are actually fully mapped, make the start/end more fine grained */ if (!IS_ALIGNED((unsigned long)_stext, SECTION_SIZE)) { unsigned long aligned_start = round_down(__pa(_stext), SECTION_SIZE); create_mapping(aligned_start, __phys_to_virt(aligned_start), __pa(_stext) - aligned_start, PAGE_KERNEL); } if (!IS_ALIGNED((unsigned long)__init_end, SECTION_SIZE)) { unsigned long aligned_end = round_up(__pa(__init_end), SECTION_SIZE); create_mapping(__pa(__init_end), (unsigned long)__init_end, aligned_end - __pa(__init_end), PAGE_KERNEL); } #endif } #ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void) { create_mapping_late(__pa(_stext), (unsigned long)_stext, (unsigned long)_etext - (unsigned long)_stext, PAGE_KERNEL_EXEC | PTE_RDONLY); } #endif void fixup_init(void) { create_mapping_late(__pa(__init_begin), (unsigned long)__init_begin, (unsigned long)__init_end - (unsigned long)__init_begin, PAGE_KERNEL); } /* * paging_init() sets up the page tables, initialises the zone memory * maps and sets up the zero page. */ void __init paging_init(void) { void *zero_page; map_mem(); fixup_executable(); /* * Finally flush the caches and tlb to ensure that we're in a * consistent state. */ flush_cache_all(); flush_tlb_all(); /* allocate the zero page. */ zero_page = early_alloc(PAGE_SIZE); bootmem_init(); empty_zero_page = virt_to_page(zero_page); /* * TTBR0 is only used for the identity mapping at this stage. Make it * point to zero page to avoid speculatively fetching new entries. */ cpu_set_reserved_ttbr0(); flush_tlb_all(); } /* * Enable the identity mapping to allow the MMU disabling. */ void setup_mm_for_reboot(void) { cpu_switch_mm(idmap_pg_dir, &init_mm); flush_tlb_all(); } /* * Check whether a kernel address is valid (derived from arch/x86/). */ int kern_addr_valid(unsigned long addr) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; if ((((long)addr) >> VA_BITS) != -1UL) return 0; pgd = pgd_offset_k(addr); if (pgd_none(*pgd)) return 0; pud = pud_offset(pgd, addr); if (pud_none(*pud)) return 0; if (pud_sect(*pud)) return pfn_valid(pud_pfn(*pud)); pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) return 0; if (pmd_sect(*pmd)) return pfn_valid(pmd_pfn(*pmd)); pte = pte_offset_kernel(pmd, addr); if (pte_none(*pte)) return 0; return pfn_valid(pte_pfn(*pte)); } #ifdef CONFIG_SPARSEMEM_VMEMMAP #ifdef CONFIG_ARM64_64K_PAGES int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) { return vmemmap_populate_basepages(start, end, node); } #else /* !CONFIG_ARM64_64K_PAGES */ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) { unsigned long addr = start; unsigned long next; pgd_t *pgd; pud_t *pud; pmd_t *pmd; do { next = pmd_addr_end(addr, end); pgd = vmemmap_pgd_populate(addr, node); if (!pgd) return -ENOMEM; pud = vmemmap_pud_populate(pgd, addr, node); if (!pud) return -ENOMEM; pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) { void *p = NULL; p = vmemmap_alloc_block_buf(PMD_SIZE, node); if (!p) return -ENOMEM; set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL)); } else vmemmap_verify((pte_t *)pmd, node, addr, next); } while (addr = next, addr != end); return 0; } #endif /* CONFIG_ARM64_64K_PAGES */ void vmemmap_free(unsigned long start, unsigned long end) { } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; #if CONFIG_ARM64_PGTABLE_LEVELS > 2 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss; #endif #if CONFIG_ARM64_PGTABLE_LEVELS > 3 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss; #endif static inline pud_t * fixmap_pud(unsigned long addr) { pgd_t *pgd = pgd_offset_k(addr); BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd)); return pud_offset(pgd, addr); } static inline pmd_t * fixmap_pmd(unsigned long addr) { pud_t *pud = fixmap_pud(addr); BUG_ON(pud_none(*pud) || pud_bad(*pud)); return pmd_offset(pud, addr); } static inline pte_t * fixmap_pte(unsigned long addr) { pmd_t *pmd = fixmap_pmd(addr); BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd)); return pte_offset_kernel(pmd, addr); } void __init early_fixmap_init(void) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; unsigned long addr = FIXADDR_START; pgd = pgd_offset_k(addr); pgd_populate(&init_mm, pgd, bm_pud); pud = pud_offset(pgd, addr); pud_populate(&init_mm, pud, bm_pmd); pmd = pmd_offset(pud, addr); pmd_populate_kernel(&init_mm, pmd, bm_pte); /* * The boot-ioremap range spans multiple pmds, for which * we are not preparted: */ BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { WARN_ON(1); pr_warn("pmd %p != %p, %p\n", pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", fix_to_virt(FIX_BTMAP_BEGIN)); pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", fix_to_virt(FIX_BTMAP_END)); pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); } } void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) { unsigned long addr = __fix_to_virt(idx); pte_t *pte; if (idx >= __end_of_fixed_addresses) { BUG(); return; } pte = fixmap_pte(addr); if (pgprot_val(flags)) { set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags)); } else { pte_clear(&init_mm, addr, pte); flush_tlb_kernel_range(addr, addr+PAGE_SIZE); } }