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 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) {
208 set_pmd(pmd, __pmd(phys | prot_sect_kernel));
210 * Check for previous table entries created during
211 * boot (__create_page_tables) and flush them.
213 if (!pmd_none(old_pmd))
216 alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys));
219 } while (pmd++, addr = next, addr != end);
222 static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
223 unsigned long end, unsigned long phys)
225 pud_t *pud = pud_offset(pgd, addr);
229 next = pud_addr_end(addr, end);
230 alloc_init_pmd(pud, addr, next, phys);
232 } while (pud++, addr = next, addr != end);
236 * Create the page directory entries and any necessary page tables for the
237 * mapping specified by 'md'.
239 static void __init create_mapping(phys_addr_t phys, unsigned long virt,
242 unsigned long addr, length, end, next;
245 if (virt < VMALLOC_START) {
246 pr_warning("BUG: not creating mapping for 0x%016llx at 0x%016lx - outside kernel range\n",
251 addr = virt & PAGE_MASK;
252 length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
254 pgd = pgd_offset_k(addr);
257 next = pgd_addr_end(addr, end);
258 alloc_init_pud(pgd, addr, next, phys);
260 } while (pgd++, addr = next, addr != end);
263 static void __init map_mem(void)
265 struct memblock_region *reg;
269 * Temporarily limit the memblock range. We need to do this as
270 * create_mapping requires puds, pmds and ptes to be allocated from
271 * memory addressable from the initial direct kernel mapping.
273 * The initial direct kernel mapping, located at swapper_pg_dir,
274 * gives us PGDIR_SIZE memory starting from PHYS_OFFSET (which must be
275 * aligned to 2MB as per Documentation/arm64/booting.txt).
277 limit = PHYS_OFFSET + PGDIR_SIZE;
278 memblock_set_current_limit(limit);
280 /* map all the memory banks */
281 for_each_memblock(memory, reg) {
282 phys_addr_t start = reg->base;
283 phys_addr_t end = start + reg->size;
288 #ifndef CONFIG_ARM64_64K_PAGES
290 * For the first memory bank align the start address and
291 * current memblock limit to prevent create_mapping() from
292 * allocating pte page tables from unmapped memory.
293 * When 64K pages are enabled, the pte page table for the
294 * first PGDIR_SIZE is already present in swapper_pg_dir.
297 start = ALIGN(start, PMD_SIZE);
299 limit = end & PMD_MASK;
300 memblock_set_current_limit(limit);
304 create_mapping(start, __phys_to_virt(start), end - start);
307 /* Limit no longer required. */
308 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
312 * paging_init() sets up the page tables, initialises the zone memory
313 * maps and sets up the zero page.
315 void __init paging_init(void)
322 * Finally flush the caches and tlb to ensure that we're in a
328 /* allocate the zero page. */
329 zero_page = early_alloc(PAGE_SIZE);
333 empty_zero_page = virt_to_page(zero_page);
336 * TTBR0 is only used for the identity mapping at this stage. Make it
337 * point to zero page to avoid speculatively fetching new entries.
339 cpu_set_reserved_ttbr0();
344 * Enable the identity mapping to allow the MMU disabling.
346 void setup_mm_for_reboot(void)
348 cpu_switch_mm(idmap_pg_dir, &init_mm);
353 * Check whether a kernel address is valid (derived from arch/x86/).
355 int kern_addr_valid(unsigned long addr)
362 if ((((long)addr) >> VA_BITS) != -1UL)
365 pgd = pgd_offset_k(addr);
369 pud = pud_offset(pgd, addr);
373 pmd = pmd_offset(pud, addr);
378 return pfn_valid(pmd_pfn(*pmd));
380 pte = pte_offset_kernel(pmd, addr);
384 return pfn_valid(pte_pfn(*pte));
386 #ifdef CONFIG_SPARSEMEM_VMEMMAP
387 #ifdef CONFIG_ARM64_64K_PAGES
388 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
390 return vmemmap_populate_basepages(start, end, node);
392 #else /* !CONFIG_ARM64_64K_PAGES */
393 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
395 unsigned long addr = start;
402 next = pmd_addr_end(addr, end);
404 pgd = vmemmap_pgd_populate(addr, node);
408 pud = vmemmap_pud_populate(pgd, addr, node);
412 pmd = pmd_offset(pud, addr);
413 if (pmd_none(*pmd)) {
416 p = vmemmap_alloc_block_buf(PMD_SIZE, node);
420 set_pmd(pmd, __pmd(__pa(p) | prot_sect_kernel));
422 vmemmap_verify((pte_t *)pmd, node, addr, next);
423 } while (addr = next, addr != end);
427 #endif /* CONFIG_ARM64_64K_PAGES */
428 void vmemmap_free(unsigned long start, unsigned long end)
431 #endif /* CONFIG_SPARSEMEM_VMEMMAP */