2 * Based on arch/arm/mm/mmu.c
4 * Copyright (C) 1995-2005 Russell King
5 * Copyright (C) 2012 ARM Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #include <linux/export.h>
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/init.h>
24 #include <linux/mman.h>
25 #include <linux/nodemask.h>
26 #include <linux/memblock.h>
30 #include <asm/cputype.h>
31 #include <asm/sections.h>
32 #include <asm/setup.h>
33 #include <asm/sizes.h>
35 #include <asm/mmu_context.h>
40 * Empty_zero_page is a special page that is used for zero-initialized data
43 struct page *empty_zero_page;
44 EXPORT_SYMBOL(empty_zero_page);
46 pgprot_t pgprot_default;
47 EXPORT_SYMBOL(pgprot_default);
49 static pmdval_t prot_sect_kernel;
52 const char policy[16];
57 static struct cachepolicy cache_policies[] __initdata = {
60 .mair = 0x44, /* inner, outer non-cacheable */
61 .tcr = TCR_IRGN_NC | TCR_ORGN_NC,
63 .policy = "writethrough",
64 .mair = 0xaa, /* inner, outer write-through, read-allocate */
65 .tcr = TCR_IRGN_WT | TCR_ORGN_WT,
67 .policy = "writeback",
68 .mair = 0xee, /* inner, outer write-back, read-allocate */
69 .tcr = TCR_IRGN_WBnWA | TCR_ORGN_WBnWA,
74 * These are useful for identifying cache coherency problems by allowing the
75 * cache or the cache and writebuffer to be turned off. It changes the Normal
76 * memory caching attributes in the MAIR_EL1 register.
78 static int __init early_cachepolicy(char *p)
83 for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
84 int len = strlen(cache_policies[i].policy);
86 if (memcmp(p, cache_policies[i].policy, len) == 0)
89 if (i == ARRAY_SIZE(cache_policies)) {
90 pr_err("ERROR: unknown or unsupported cache policy: %s\n", p);
97 * Modify MT_NORMAL attributes in MAIR_EL1.
100 " mrs %0, mair_el1\n"
101 " bfi %0, %1, #%2, #8\n"
102 " msr mair_el1, %0\n"
105 : "r" (cache_policies[i].mair), "i" (MT_NORMAL * 8));
108 * Modify TCR PTW cacheability attributes.
117 : "r" (cache_policies[i].tcr), "r" (TCR_IRGN_MASK | TCR_ORGN_MASK));
123 early_param("cachepolicy", early_cachepolicy);
126 * Adjust the PMD section entries according to the CPU in use.
128 static void __init init_mem_pgprot(void)
130 pteval_t default_pgprot;
133 default_pgprot = PTE_ATTRINDX(MT_NORMAL);
134 prot_sect_kernel = PMD_TYPE_SECT | PMD_SECT_AF | PMD_ATTRINDX(MT_NORMAL);
138 * Mark memory with the "shared" attribute for SMP systems
140 default_pgprot |= PTE_SHARED;
141 prot_sect_kernel |= PMD_SECT_S;
144 for (i = 0; i < 16; i++) {
145 unsigned long v = pgprot_val(protection_map[i]);
146 protection_map[i] = __pgprot(v | default_pgprot);
149 pgprot_default = __pgprot(PTE_TYPE_PAGE | PTE_AF | default_pgprot);
152 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
153 unsigned long size, pgprot_t vma_prot)
156 return pgprot_noncached(vma_prot);
157 else if (file->f_flags & O_SYNC)
158 return pgprot_writecombine(vma_prot);
161 EXPORT_SYMBOL(phys_mem_access_prot);
163 static void __init *early_alloc(unsigned long sz)
165 void *ptr = __va(memblock_alloc(sz, sz));
170 static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
171 unsigned long end, unsigned long pfn)
175 if (pmd_none(*pmd)) {
176 pte = early_alloc(PTRS_PER_PTE * sizeof(pte_t));
177 __pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE);
179 BUG_ON(pmd_bad(*pmd));
181 pte = pte_offset_kernel(pmd, addr);
183 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
185 } while (pte++, addr += PAGE_SIZE, addr != end);
188 static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
189 unsigned long end, phys_addr_t phys)
195 * Check for initial section mappings in the pgd/pud and remove them.
197 if (pud_none(*pud) || pud_bad(*pud)) {
198 pmd = early_alloc(PTRS_PER_PMD * sizeof(pmd_t));
199 pud_populate(&init_mm, pud, pmd);
202 pmd = pmd_offset(pud, addr);
204 next = pmd_addr_end(addr, end);
205 /* try section mapping first */
206 if (((addr | next | phys) & ~SECTION_MASK) == 0)
207 set_pmd(pmd, __pmd(phys | prot_sect_kernel));
209 alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys));
211 } while (pmd++, addr = next, addr != end);
214 static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
215 unsigned long end, unsigned long phys)
217 pud_t *pud = pud_offset(pgd, addr);
221 next = pud_addr_end(addr, end);
222 alloc_init_pmd(pud, addr, next, phys);
224 } while (pud++, addr = next, addr != end);
228 * Create the page directory entries and any necessary page tables for the
229 * mapping specified by 'md'.
231 static void __init create_mapping(phys_addr_t phys, unsigned long virt,
234 unsigned long addr, length, end, next;
237 if (virt < VMALLOC_START) {
238 pr_warning("BUG: not creating mapping for 0x%016llx at 0x%016lx - outside kernel range\n",
243 addr = virt & PAGE_MASK;
244 length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
246 pgd = pgd_offset_k(addr);
249 next = pgd_addr_end(addr, end);
250 alloc_init_pud(pgd, addr, next, phys);
252 } while (pgd++, addr = next, addr != end);
255 #ifdef CONFIG_EARLY_PRINTK
257 * Create an early I/O mapping using the pgd/pmd entries already populated
258 * in head.S as this function is called too early to allocated any memory. The
259 * mapping size is 2MB with 4KB pages or 64KB or 64KB pages.
261 void __iomem * __init early_io_map(phys_addr_t phys, unsigned long virt)
263 unsigned long size, mask;
264 bool page64k = IS_ENABLED(CONFIG_ARM64_64K_PAGES);
271 * No early pte entries with !ARM64_64K_PAGES configuration, so using
274 size = page64k ? PAGE_SIZE : SECTION_SIZE;
277 pgd = pgd_offset_k(virt);
278 pud = pud_offset(pgd, virt);
281 pmd = pmd_offset(pud, virt);
286 pte = pte_offset_kernel(pmd, virt);
287 set_pte(pte, __pte((phys & mask) | PROT_DEVICE_nGnRE));
289 set_pmd(pmd, __pmd((phys & mask) | PROT_SECT_DEVICE_nGnRE));
292 return (void __iomem *)((virt & mask) + (phys & ~mask));
296 static void __init map_mem(void)
298 struct memblock_region *reg;
300 /* map all the memory banks */
301 for_each_memblock(memory, reg) {
302 phys_addr_t start = reg->base;
303 phys_addr_t end = start + reg->size;
308 create_mapping(start, __phys_to_virt(start), end - start);
313 * paging_init() sets up the page tables, initialises the zone memory
314 * maps and sets up the zero page.
316 void __init paging_init(void)
321 * Maximum PGDIR_SIZE addressable via the initial direct kernel
322 * mapping in swapper_pg_dir.
324 memblock_set_current_limit((PHYS_OFFSET & PGDIR_MASK) + PGDIR_SIZE);
330 * Finally flush the caches and tlb to ensure that we're in a
336 /* allocate the zero page. */
337 zero_page = early_alloc(PAGE_SIZE);
341 empty_zero_page = virt_to_page(zero_page);
342 __flush_dcache_page(empty_zero_page);
345 * TTBR0 is only used for the identity mapping at this stage. Make it
346 * point to zero page to avoid speculatively fetching new entries.
348 cpu_set_reserved_ttbr0();
353 * Enable the identity mapping to allow the MMU disabling.
355 void setup_mm_for_reboot(void)
357 cpu_switch_mm(idmap_pg_dir, &init_mm);
362 * Check whether a kernel address is valid (derived from arch/x86/).
364 int kern_addr_valid(unsigned long addr)
371 if ((((long)addr) >> VA_BITS) != -1UL)
374 pgd = pgd_offset_k(addr);
378 pud = pud_offset(pgd, addr);
382 pmd = pmd_offset(pud, addr);
386 pte = pte_offset_kernel(pmd, addr);
390 return pfn_valid(pte_pfn(*pte));
392 #ifdef CONFIG_SPARSEMEM_VMEMMAP
393 #ifdef CONFIG_ARM64_64K_PAGES
394 int __meminit vmemmap_populate(struct page *start_page,
395 unsigned long size, int node)
397 return vmemmap_populate_basepages(start_page, size, node);
399 #else /* !CONFIG_ARM64_64K_PAGES */
400 int __meminit vmemmap_populate(struct page *start_page,
401 unsigned long size, int node)
403 unsigned long addr = (unsigned long)start_page;
404 unsigned long end = (unsigned long)(start_page + size);
411 next = pmd_addr_end(addr, end);
413 pgd = vmemmap_pgd_populate(addr, node);
417 pud = vmemmap_pud_populate(pgd, addr, node);
421 pmd = pmd_offset(pud, addr);
422 if (pmd_none(*pmd)) {
425 p = vmemmap_alloc_block_buf(PMD_SIZE, node);
429 set_pmd(pmd, __pmd(__pa(p) | prot_sect_kernel));
431 vmemmap_verify((pte_t *)pmd, node, addr, next);
432 } while (addr = next, addr != end);
436 #endif /* CONFIG_ARM64_64K_PAGES */
437 void vmemmap_free(struct page *memmap, unsigned long nr_pages)
440 #endif /* CONFIG_SPARSEMEM_VMEMMAP */