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>
29 #include <linux/slab.h>
30 #include <linux/stop_machine.h>
32 #include <asm/cputype.h>
33 #include <asm/fixmap.h>
34 #include <asm/sections.h>
35 #include <asm/setup.h>
36 #include <asm/sizes.h>
38 #include <asm/memblock.h>
39 #include <asm/mmu_context.h>
43 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
46 * Empty_zero_page is a special page that is used for zero-initialized data
49 struct page *empty_zero_page;
50 EXPORT_SYMBOL(empty_zero_page);
52 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
53 unsigned long size, pgprot_t vma_prot)
56 return pgprot_noncached(vma_prot);
57 else if (file->f_flags & O_SYNC)
58 return pgprot_writecombine(vma_prot);
61 EXPORT_SYMBOL(phys_mem_access_prot);
63 static void __init *early_alloc(unsigned long sz)
65 void *ptr = __va(memblock_alloc(sz, sz));
72 * remap a PMD into pages
74 static void split_pmd(pmd_t *pmd, pte_t *pte)
76 unsigned long pfn = pmd_pfn(*pmd);
81 * Need to have the least restrictive permissions available
82 * permissions will be fixed up later
84 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
86 } while (pte++, i++, i < PTRS_PER_PTE);
89 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
90 unsigned long end, unsigned long pfn,
92 void *(*alloc)(unsigned long size))
96 if (pmd_none(*pmd) || pmd_sect(*pmd)) {
97 pte = alloc(PTRS_PER_PTE * sizeof(pte_t));
100 __pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE);
103 BUG_ON(pmd_bad(*pmd));
105 pte = pte_offset_kernel(pmd, addr);
107 set_pte(pte, pfn_pte(pfn, prot));
109 } while (pte++, addr += PAGE_SIZE, addr != end);
112 void split_pud(pud_t *old_pud, pmd_t *pmd)
114 unsigned long addr = pud_pfn(*old_pud) << PAGE_SHIFT;
115 pgprot_t prot = __pgprot(pud_val(*old_pud) ^ addr);
119 set_pmd(pmd, __pmd(addr | prot));
121 } while (pmd++, i++, i < PTRS_PER_PMD);
124 static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
125 unsigned long addr, unsigned long end,
126 phys_addr_t phys, pgprot_t prot,
127 void *(*alloc)(unsigned long size))
133 * Check for initial section mappings in the pgd/pud and remove them.
135 if (pud_none(*pud) || pud_sect(*pud)) {
136 pmd = alloc(PTRS_PER_PMD * sizeof(pmd_t));
137 if (pud_sect(*pud)) {
139 * need to have the 1G of mappings continue to be
144 pud_populate(mm, pud, pmd);
147 BUG_ON(pud_bad(*pud));
149 pmd = pmd_offset(pud, addr);
151 next = pmd_addr_end(addr, end);
152 /* try section mapping first */
153 if (((addr | next | phys) & ~SECTION_MASK) == 0) {
155 set_pmd(pmd, __pmd(phys |
156 pgprot_val(mk_sect_prot(prot))));
158 * Check for previous table entries created during
159 * boot (__create_page_tables) and flush them.
161 if (!pmd_none(old_pmd)) {
163 if (pmd_table(old_pmd)) {
164 phys_addr_t table = __pa(pte_offset_map(&old_pmd, 0));
165 if (!WARN_ON_ONCE(slab_is_available()))
166 memblock_free(table, PAGE_SIZE);
170 alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
174 } while (pmd++, addr = next, addr != end);
177 static inline bool use_1G_block(unsigned long addr, unsigned long next,
180 if (PAGE_SHIFT != 12)
183 if (((addr | next | phys) & ~PUD_MASK) != 0)
189 static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
190 unsigned long addr, unsigned long end,
191 phys_addr_t phys, pgprot_t prot,
192 void *(*alloc)(unsigned long size))
197 if (pgd_none(*pgd)) {
198 pud = alloc(PTRS_PER_PUD * sizeof(pud_t));
199 pgd_populate(mm, pgd, pud);
201 BUG_ON(pgd_bad(*pgd));
203 pud = pud_offset(pgd, addr);
205 next = pud_addr_end(addr, end);
208 * For 4K granule only, attempt to put down a 1GB block
210 if (use_1G_block(addr, next, phys)) {
211 pud_t old_pud = *pud;
212 set_pud(pud, __pud(phys |
213 pgprot_val(mk_sect_prot(prot))));
216 * If we have an old value for a pud, it will
217 * be pointing to a pmd table that we no longer
218 * need (from swapper_pg_dir).
220 * Look up the old pmd table and free it.
222 if (!pud_none(old_pud)) {
224 if (pud_table(old_pud)) {
225 phys_addr_t table = __pa(pmd_offset(&old_pud, 0));
226 if (!WARN_ON_ONCE(slab_is_available()))
227 memblock_free(table, PAGE_SIZE);
231 alloc_init_pmd(mm, pud, addr, next, phys, prot, alloc);
234 } while (pud++, addr = next, addr != end);
238 * Create the page directory entries and any necessary page tables for the
239 * mapping specified by 'md'.
241 static void __create_mapping(struct mm_struct *mm, pgd_t *pgd,
242 phys_addr_t phys, unsigned long virt,
243 phys_addr_t size, pgprot_t prot,
244 void *(*alloc)(unsigned long size))
246 unsigned long addr, length, end, next;
248 addr = virt & PAGE_MASK;
249 length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
253 next = pgd_addr_end(addr, end);
254 alloc_init_pud(mm, pgd, addr, next, phys, prot, alloc);
256 } while (pgd++, addr = next, addr != end);
259 static void *late_alloc(unsigned long size)
263 BUG_ON(size > PAGE_SIZE);
264 ptr = (void *)__get_free_page(PGALLOC_GFP);
269 static void __ref create_mapping(phys_addr_t phys, unsigned long virt,
270 phys_addr_t size, pgprot_t prot)
272 if (virt < VMALLOC_START) {
273 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
277 __create_mapping(&init_mm, pgd_offset_k(virt & PAGE_MASK), phys, virt,
278 size, prot, early_alloc);
281 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
282 unsigned long virt, phys_addr_t size,
285 __create_mapping(mm, pgd_offset(mm, virt), phys, virt, size, prot,
289 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
290 phys_addr_t size, pgprot_t prot)
292 if (virt < VMALLOC_START) {
293 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
298 return __create_mapping(&init_mm, pgd_offset_k(virt & PAGE_MASK),
299 phys, virt, size, prot, late_alloc);
302 #ifdef CONFIG_DEBUG_RODATA
303 static void __init __map_memblock(phys_addr_t start, phys_addr_t end)
306 * Set up the executable regions using the existing section mappings
307 * for now. This will get more fine grained later once all memory
310 unsigned long kernel_x_start = round_down(__pa(_stext), SECTION_SIZE);
311 unsigned long kernel_x_end = round_up(__pa(__init_end), SECTION_SIZE);
313 if (end < kernel_x_start) {
314 create_mapping(start, __phys_to_virt(start),
315 end - start, PAGE_KERNEL);
316 } else if (start >= kernel_x_end) {
317 create_mapping(start, __phys_to_virt(start),
318 end - start, PAGE_KERNEL);
320 if (start < kernel_x_start)
321 create_mapping(start, __phys_to_virt(start),
322 kernel_x_start - start,
324 create_mapping(kernel_x_start,
325 __phys_to_virt(kernel_x_start),
326 kernel_x_end - kernel_x_start,
328 if (kernel_x_end < end)
329 create_mapping(kernel_x_end,
330 __phys_to_virt(kernel_x_end),
337 static void __init __map_memblock(phys_addr_t start, phys_addr_t end)
339 create_mapping(start, __phys_to_virt(start), end - start,
344 static void __init map_mem(void)
346 struct memblock_region *reg;
350 * Temporarily limit the memblock range. We need to do this as
351 * create_mapping requires puds, pmds and ptes to be allocated from
352 * memory addressable from the initial direct kernel mapping.
354 * The initial direct kernel mapping, located at swapper_pg_dir, gives
355 * us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
356 * PHYS_OFFSET (which must be aligned to 2MB as per
357 * Documentation/arm64/booting.txt).
359 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
360 limit = PHYS_OFFSET + PMD_SIZE;
362 limit = PHYS_OFFSET + PUD_SIZE;
363 memblock_set_current_limit(limit);
365 /* map all the memory banks */
366 for_each_memblock(memory, reg) {
367 phys_addr_t start = reg->base;
368 phys_addr_t end = start + reg->size;
373 #ifndef CONFIG_ARM64_64K_PAGES
375 * For the first memory bank align the start address and
376 * current memblock limit to prevent create_mapping() from
377 * allocating pte page tables from unmapped memory.
378 * When 64K pages are enabled, the pte page table for the
379 * first PGDIR_SIZE is already present in swapper_pg_dir.
382 start = ALIGN(start, PMD_SIZE);
384 limit = end & PMD_MASK;
385 memblock_set_current_limit(limit);
388 __map_memblock(start, end);
391 /* Limit no longer required. */
392 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
395 void __init fixup_executable(void)
397 #ifdef CONFIG_DEBUG_RODATA
398 /* now that we are actually fully mapped, make the start/end more fine grained */
399 if (!IS_ALIGNED((unsigned long)_stext, SECTION_SIZE)) {
400 unsigned long aligned_start = round_down(__pa(_stext),
403 create_mapping(aligned_start, __phys_to_virt(aligned_start),
404 __pa(_stext) - aligned_start,
408 if (!IS_ALIGNED((unsigned long)__init_end, SECTION_SIZE)) {
409 unsigned long aligned_end = round_up(__pa(__init_end),
411 create_mapping(__pa(__init_end), (unsigned long)__init_end,
412 aligned_end - __pa(__init_end),
418 #ifdef CONFIG_DEBUG_RODATA
419 void mark_rodata_ro(void)
421 create_mapping_late(__pa(_stext), (unsigned long)_stext,
422 (unsigned long)_etext - (unsigned long)_stext,
423 PAGE_KERNEL_EXEC | PTE_RDONLY);
428 void fixup_init(void)
430 create_mapping_late(__pa(__init_begin), (unsigned long)__init_begin,
431 (unsigned long)__init_end - (unsigned long)__init_begin,
436 * paging_init() sets up the page tables, initialises the zone memory
437 * maps and sets up the zero page.
439 void __init paging_init(void)
446 /* allocate the zero page. */
447 zero_page = early_alloc(PAGE_SIZE);
451 empty_zero_page = virt_to_page(zero_page);
454 * TTBR0 is only used for the identity mapping at this stage. Make it
455 * point to zero page to avoid speculatively fetching new entries.
457 cpu_set_reserved_ttbr0();
459 cpu_set_default_tcr_t0sz();
463 * Enable the identity mapping to allow the MMU disabling.
465 void setup_mm_for_reboot(void)
467 cpu_set_reserved_ttbr0();
469 cpu_set_idmap_tcr_t0sz();
470 cpu_switch_mm(idmap_pg_dir, &init_mm);
474 * Check whether a kernel address is valid (derived from arch/x86/).
476 int kern_addr_valid(unsigned long addr)
483 if ((((long)addr) >> VA_BITS) != -1UL)
486 pgd = pgd_offset_k(addr);
490 pud = pud_offset(pgd, addr);
495 return pfn_valid(pud_pfn(*pud));
497 pmd = pmd_offset(pud, addr);
502 return pfn_valid(pmd_pfn(*pmd));
504 pte = pte_offset_kernel(pmd, addr);
508 return pfn_valid(pte_pfn(*pte));
510 #ifdef CONFIG_SPARSEMEM_VMEMMAP
511 #ifdef CONFIG_ARM64_64K_PAGES
512 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
514 return vmemmap_populate_basepages(start, end, node);
516 #else /* !CONFIG_ARM64_64K_PAGES */
517 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
519 unsigned long addr = start;
526 next = pmd_addr_end(addr, end);
528 pgd = vmemmap_pgd_populate(addr, node);
532 pud = vmemmap_pud_populate(pgd, addr, node);
536 pmd = pmd_offset(pud, addr);
537 if (pmd_none(*pmd)) {
540 p = vmemmap_alloc_block_buf(PMD_SIZE, node);
544 set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
546 vmemmap_verify((pte_t *)pmd, node, addr, next);
547 } while (addr = next, addr != end);
551 #endif /* CONFIG_ARM64_64K_PAGES */
552 void vmemmap_free(unsigned long start, unsigned long end)
555 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
557 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
558 #if CONFIG_PGTABLE_LEVELS > 2
559 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss;
561 #if CONFIG_PGTABLE_LEVELS > 3
562 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss;
565 static inline pud_t * fixmap_pud(unsigned long addr)
567 pgd_t *pgd = pgd_offset_k(addr);
569 BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
571 return pud_offset(pgd, addr);
574 static inline pmd_t * fixmap_pmd(unsigned long addr)
576 pud_t *pud = fixmap_pud(addr);
578 BUG_ON(pud_none(*pud) || pud_bad(*pud));
580 return pmd_offset(pud, addr);
583 static inline pte_t * fixmap_pte(unsigned long addr)
585 pmd_t *pmd = fixmap_pmd(addr);
587 BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
589 return pte_offset_kernel(pmd, addr);
592 void __init early_fixmap_init(void)
597 unsigned long addr = FIXADDR_START;
599 pgd = pgd_offset_k(addr);
600 pgd_populate(&init_mm, pgd, bm_pud);
601 pud = pud_offset(pgd, addr);
602 pud_populate(&init_mm, pud, bm_pmd);
603 pmd = pmd_offset(pud, addr);
604 pmd_populate_kernel(&init_mm, pmd, bm_pte);
607 * The boot-ioremap range spans multiple pmds, for which
608 * we are not preparted:
610 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
611 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
613 if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
614 || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
616 pr_warn("pmd %p != %p, %p\n",
617 pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
618 fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
619 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
620 fix_to_virt(FIX_BTMAP_BEGIN));
621 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n",
622 fix_to_virt(FIX_BTMAP_END));
624 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
625 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN);
629 void __set_fixmap(enum fixed_addresses idx,
630 phys_addr_t phys, pgprot_t flags)
632 unsigned long addr = __fix_to_virt(idx);
635 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
637 pte = fixmap_pte(addr);
639 if (pgprot_val(flags)) {
640 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
642 pte_clear(&init_mm, addr, pte);
643 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);