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/memblock.h>
36 #include <asm/mmu_context.h>
41 * Empty_zero_page is a special page that is used for zero-initialized data
44 struct page *empty_zero_page;
45 EXPORT_SYMBOL(empty_zero_page);
48 const char policy[16];
53 static struct cachepolicy cache_policies[] __initdata = {
56 .mair = 0x44, /* inner, outer non-cacheable */
57 .tcr = TCR_IRGN_NC | TCR_ORGN_NC,
59 .policy = "writethrough",
60 .mair = 0xaa, /* inner, outer write-through, read-allocate */
61 .tcr = TCR_IRGN_WT | TCR_ORGN_WT,
63 .policy = "writeback",
64 .mair = 0xee, /* inner, outer write-back, read-allocate */
65 .tcr = TCR_IRGN_WBnWA | TCR_ORGN_WBnWA,
70 * These are useful for identifying cache coherency problems by allowing the
71 * cache or the cache and writebuffer to be turned off. It changes the Normal
72 * memory caching attributes in the MAIR_EL1 register.
74 static int __init early_cachepolicy(char *p)
79 for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
80 int len = strlen(cache_policies[i].policy);
82 if (memcmp(p, cache_policies[i].policy, len) == 0)
85 if (i == ARRAY_SIZE(cache_policies)) {
86 pr_err("ERROR: unknown or unsupported cache policy: %s\n", p);
93 * Modify MT_NORMAL attributes in MAIR_EL1.
97 " bfi %0, %1, %2, #8\n"
101 : "r" (cache_policies[i].mair), "i" (MT_NORMAL * 8));
104 * Modify TCR PTW cacheability attributes.
113 : "r" (cache_policies[i].tcr), "r" (TCR_IRGN_MASK | TCR_ORGN_MASK));
119 early_param("cachepolicy", early_cachepolicy);
121 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
122 unsigned long size, pgprot_t vma_prot)
125 return pgprot_noncached(vma_prot);
126 else if (file->f_flags & O_SYNC)
127 return pgprot_writecombine(vma_prot);
130 EXPORT_SYMBOL(phys_mem_access_prot);
132 static void __init *early_alloc(unsigned long sz)
134 void *ptr = __va(memblock_alloc(sz, sz));
139 static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
140 unsigned long end, unsigned long pfn,
145 if (pmd_none(*pmd)) {
146 pte = early_alloc(PTRS_PER_PTE * sizeof(pte_t));
147 __pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE);
149 BUG_ON(pmd_bad(*pmd));
151 pte = pte_offset_kernel(pmd, addr);
153 set_pte(pte, pfn_pte(pfn, prot));
155 } while (pte++, addr += PAGE_SIZE, addr != end);
158 static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
159 unsigned long end, phys_addr_t phys,
168 prot_sect = PROT_SECT_DEVICE_nGnRE;
169 prot_pte = __pgprot(PROT_DEVICE_nGnRE);
171 prot_sect = PROT_SECT_NORMAL_EXEC;
172 prot_pte = PAGE_KERNEL_EXEC;
176 * Check for initial section mappings in the pgd/pud and remove them.
178 if (pud_none(*pud) || pud_bad(*pud)) {
179 pmd = early_alloc(PTRS_PER_PMD * sizeof(pmd_t));
180 pud_populate(&init_mm, pud, pmd);
183 pmd = pmd_offset(pud, addr);
185 next = pmd_addr_end(addr, end);
186 /* try section mapping first */
187 if (((addr | next | phys) & ~SECTION_MASK) == 0) {
189 set_pmd(pmd, __pmd(phys | prot_sect));
191 * Check for previous table entries created during
192 * boot (__create_page_tables) and flush them.
194 if (!pmd_none(old_pmd))
197 alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
201 } while (pmd++, addr = next, addr != end);
204 static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
205 unsigned long end, unsigned long phys,
211 if (pgd_none(*pgd)) {
212 pud = early_alloc(PTRS_PER_PUD * sizeof(pud_t));
213 pgd_populate(&init_mm, pgd, pud);
215 BUG_ON(pgd_bad(*pgd));
217 pud = pud_offset(pgd, addr);
219 next = pud_addr_end(addr, end);
222 * For 4K granule only, attempt to put down a 1GB block
224 if (!map_io && (PAGE_SHIFT == 12) &&
225 ((addr | next | phys) & ~PUD_MASK) == 0) {
226 pud_t old_pud = *pud;
227 set_pud(pud, __pud(phys | PROT_SECT_NORMAL_EXEC));
230 * If we have an old value for a pud, it will
231 * be pointing to a pmd table that we no longer
232 * need (from swapper_pg_dir).
234 * Look up the old pmd table and free it.
236 if (!pud_none(old_pud)) {
237 phys_addr_t table = __pa(pmd_offset(&old_pud, 0));
238 memblock_free(table, PAGE_SIZE);
242 alloc_init_pmd(pud, addr, next, phys, map_io);
245 } while (pud++, addr = next, addr != end);
249 * Create the page directory entries and any necessary page tables for the
250 * mapping specified by 'md'.
252 static void __init __create_mapping(pgd_t *pgd, phys_addr_t phys,
253 unsigned long virt, phys_addr_t size,
256 unsigned long addr, length, end, next;
258 addr = virt & PAGE_MASK;
259 length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
263 next = pgd_addr_end(addr, end);
264 alloc_init_pud(pgd, addr, next, phys, map_io);
266 } while (pgd++, addr = next, addr != end);
269 static void __init create_mapping(phys_addr_t phys, unsigned long virt,
272 if (virt < VMALLOC_START) {
273 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
277 __create_mapping(pgd_offset_k(virt & PAGE_MASK), phys, virt, size, 0);
280 void __init create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io)
282 if ((addr >> PGDIR_SHIFT) >= ARRAY_SIZE(idmap_pg_dir)) {
283 pr_warn("BUG: not creating id mapping for %pa\n", &addr);
286 __create_mapping(&idmap_pg_dir[pgd_index(addr)],
287 addr, addr, size, map_io);
290 static void __init map_mem(void)
292 struct memblock_region *reg;
296 * Temporarily limit the memblock range. We need to do this as
297 * create_mapping requires puds, pmds and ptes to be allocated from
298 * memory addressable from the initial direct kernel mapping.
300 * The initial direct kernel mapping, located at swapper_pg_dir, gives
301 * us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
302 * PHYS_OFFSET (which must be aligned to 2MB as per
303 * Documentation/arm64/booting.txt).
305 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
306 limit = PHYS_OFFSET + PMD_SIZE;
308 limit = PHYS_OFFSET + PUD_SIZE;
309 memblock_set_current_limit(limit);
311 /* map all the memory banks */
312 for_each_memblock(memory, reg) {
313 phys_addr_t start = reg->base;
314 phys_addr_t end = start + reg->size;
319 #ifndef CONFIG_ARM64_64K_PAGES
321 * For the first memory bank align the start address and
322 * current memblock limit to prevent create_mapping() from
323 * allocating pte page tables from unmapped memory.
324 * When 64K pages are enabled, the pte page table for the
325 * first PGDIR_SIZE is already present in swapper_pg_dir.
328 start = ALIGN(start, PMD_SIZE);
330 limit = end & PMD_MASK;
331 memblock_set_current_limit(limit);
335 create_mapping(start, __phys_to_virt(start), end - start);
338 /* Limit no longer required. */
339 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
343 * paging_init() sets up the page tables, initialises the zone memory
344 * maps and sets up the zero page.
346 void __init paging_init(void)
353 * Finally flush the caches and tlb to ensure that we're in a
359 /* allocate the zero page. */
360 zero_page = early_alloc(PAGE_SIZE);
364 empty_zero_page = virt_to_page(zero_page);
367 * TTBR0 is only used for the identity mapping at this stage. Make it
368 * point to zero page to avoid speculatively fetching new entries.
370 cpu_set_reserved_ttbr0();
375 * Enable the identity mapping to allow the MMU disabling.
377 void setup_mm_for_reboot(void)
379 cpu_switch_mm(idmap_pg_dir, &init_mm);
384 * Check whether a kernel address is valid (derived from arch/x86/).
386 int kern_addr_valid(unsigned long addr)
393 if ((((long)addr) >> VA_BITS) != -1UL)
396 pgd = pgd_offset_k(addr);
400 pud = pud_offset(pgd, addr);
405 return pfn_valid(pud_pfn(*pud));
407 pmd = pmd_offset(pud, addr);
412 return pfn_valid(pmd_pfn(*pmd));
414 pte = pte_offset_kernel(pmd, addr);
418 return pfn_valid(pte_pfn(*pte));
420 #ifdef CONFIG_SPARSEMEM_VMEMMAP
421 #ifdef CONFIG_ARM64_64K_PAGES
422 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
424 return vmemmap_populate_basepages(start, end, node);
426 #else /* !CONFIG_ARM64_64K_PAGES */
427 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
429 unsigned long addr = start;
436 next = pmd_addr_end(addr, end);
438 pgd = vmemmap_pgd_populate(addr, node);
442 pud = vmemmap_pud_populate(pgd, addr, node);
446 pmd = pmd_offset(pud, addr);
447 if (pmd_none(*pmd)) {
450 p = vmemmap_alloc_block_buf(PMD_SIZE, node);
454 set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
456 vmemmap_verify((pte_t *)pmd, node, addr, next);
457 } while (addr = next, addr != end);
461 #endif /* CONFIG_ARM64_64K_PAGES */
462 void vmemmap_free(unsigned long start, unsigned long end)
465 #endif /* CONFIG_SPARSEMEM_VMEMMAP */