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>
44 * Empty_zero_page is a special page that is used for zero-initialized data
47 struct page
*empty_zero_page
;
48 EXPORT_SYMBOL(empty_zero_page
);
50 pgprot_t
phys_mem_access_prot(struct file
*file
, unsigned long pfn
,
51 unsigned long size
, pgprot_t vma_prot
)
54 return pgprot_noncached(vma_prot
);
55 else if (file
->f_flags
& O_SYNC
)
56 return pgprot_writecombine(vma_prot
);
59 EXPORT_SYMBOL(phys_mem_access_prot
);
61 static void __init
*early_alloc(unsigned long sz
)
63 void *ptr
= __va(memblock_alloc(sz
, sz
));
70 * remap a PMD into pages
72 static void split_pmd(pmd_t
*pmd
, pte_t
*pte
)
74 unsigned long pfn
= pmd_pfn(*pmd
);
79 * Need to have the least restrictive permissions available
80 * permissions will be fixed up later
82 set_pte(pte
, pfn_pte(pfn
, PAGE_KERNEL_EXEC
));
84 } while (pte
++, i
++, i
< PTRS_PER_PTE
);
87 static void alloc_init_pte(pmd_t
*pmd
, unsigned long addr
,
88 unsigned long end
, unsigned long pfn
,
90 void *(*alloc
)(unsigned long size
))
94 if (pmd_none(*pmd
) || pmd_sect(*pmd
)) {
95 pte
= alloc(PTRS_PER_PTE
* sizeof(pte_t
));
98 __pmd_populate(pmd
, __pa(pte
), PMD_TYPE_TABLE
);
101 BUG_ON(pmd_bad(*pmd
));
103 pte
= pte_offset_kernel(pmd
, addr
);
105 set_pte(pte
, pfn_pte(pfn
, prot
));
107 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
110 void split_pud(pud_t
*old_pud
, pmd_t
*pmd
)
112 unsigned long addr
= pud_pfn(*old_pud
) << PAGE_SHIFT
;
113 pgprot_t prot
= __pgprot(pud_val(*old_pud
) ^ addr
);
117 set_pmd(pmd
, __pmd(addr
| prot
));
119 } while (pmd
++, i
++, i
< PTRS_PER_PMD
);
122 static void alloc_init_pmd(struct mm_struct
*mm
, pud_t
*pud
,
123 unsigned long addr
, unsigned long end
,
124 phys_addr_t phys
, pgprot_t prot
,
125 void *(*alloc
)(unsigned long size
))
131 * Check for initial section mappings in the pgd/pud and remove them.
133 if (pud_none(*pud
) || pud_sect(*pud
)) {
134 pmd
= alloc(PTRS_PER_PMD
* sizeof(pmd_t
));
135 if (pud_sect(*pud
)) {
137 * need to have the 1G of mappings continue to be
142 pud_populate(mm
, pud
, pmd
);
145 BUG_ON(pud_bad(*pud
));
147 pmd
= pmd_offset(pud
, addr
);
149 next
= pmd_addr_end(addr
, end
);
150 /* try section mapping first */
151 if (((addr
| next
| phys
) & ~SECTION_MASK
) == 0) {
153 set_pmd(pmd
, __pmd(phys
|
154 pgprot_val(mk_sect_prot(prot
))));
156 * Check for previous table entries created during
157 * boot (__create_page_tables) and flush them.
159 if (!pmd_none(old_pmd
)) {
161 if (pmd_table(old_pmd
)) {
162 phys_addr_t table
= __pa(pte_offset_map(&old_pmd
, 0));
163 if (!WARN_ON_ONCE(slab_is_available()))
164 memblock_free(table
, PAGE_SIZE
);
168 alloc_init_pte(pmd
, addr
, next
, __phys_to_pfn(phys
),
172 } while (pmd
++, addr
= next
, addr
!= end
);
175 static inline bool use_1G_block(unsigned long addr
, unsigned long next
,
178 if (PAGE_SHIFT
!= 12)
181 if (((addr
| next
| phys
) & ~PUD_MASK
) != 0)
187 static void alloc_init_pud(struct mm_struct
*mm
, pgd_t
*pgd
,
188 unsigned long addr
, unsigned long end
,
189 phys_addr_t phys
, pgprot_t prot
,
190 void *(*alloc
)(unsigned long size
))
195 if (pgd_none(*pgd
)) {
196 pud
= alloc(PTRS_PER_PUD
* sizeof(pud_t
));
197 pgd_populate(mm
, pgd
, pud
);
199 BUG_ON(pgd_bad(*pgd
));
201 pud
= pud_offset(pgd
, addr
);
203 next
= pud_addr_end(addr
, end
);
206 * For 4K granule only, attempt to put down a 1GB block
208 if (use_1G_block(addr
, next
, phys
)) {
209 pud_t old_pud
= *pud
;
210 set_pud(pud
, __pud(phys
|
211 pgprot_val(mk_sect_prot(prot
))));
214 * If we have an old value for a pud, it will
215 * be pointing to a pmd table that we no longer
216 * need (from swapper_pg_dir).
218 * Look up the old pmd table and free it.
220 if (!pud_none(old_pud
)) {
222 if (pud_table(old_pud
)) {
223 phys_addr_t table
= __pa(pmd_offset(&old_pud
, 0));
224 if (!WARN_ON_ONCE(slab_is_available()))
225 memblock_free(table
, PAGE_SIZE
);
229 alloc_init_pmd(mm
, pud
, addr
, next
, phys
, prot
, alloc
);
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 __create_mapping(struct mm_struct
*mm
, pgd_t
*pgd
,
240 phys_addr_t phys
, unsigned long virt
,
241 phys_addr_t size
, pgprot_t prot
,
242 void *(*alloc
)(unsigned long size
))
244 unsigned long addr
, length
, end
, next
;
246 addr
= virt
& PAGE_MASK
;
247 length
= PAGE_ALIGN(size
+ (virt
& ~PAGE_MASK
));
251 next
= pgd_addr_end(addr
, end
);
252 alloc_init_pud(mm
, pgd
, addr
, next
, phys
, prot
, alloc
);
254 } while (pgd
++, addr
= next
, addr
!= end
);
257 static void *late_alloc(unsigned long size
)
261 BUG_ON(size
> PAGE_SIZE
);
262 ptr
= (void *)__get_free_page(PGALLOC_GFP
);
267 static void __ref
create_mapping(phys_addr_t phys
, unsigned long virt
,
268 phys_addr_t size
, pgprot_t prot
)
270 if (virt
< VMALLOC_START
) {
271 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
275 __create_mapping(&init_mm
, pgd_offset_k(virt
& PAGE_MASK
), phys
, virt
,
276 size
, prot
, early_alloc
);
279 void __init
create_pgd_mapping(struct mm_struct
*mm
, phys_addr_t phys
,
280 unsigned long virt
, phys_addr_t size
,
283 __create_mapping(mm
, pgd_offset(mm
, virt
), phys
, virt
, size
, prot
,
287 static void create_mapping_late(phys_addr_t phys
, unsigned long virt
,
288 phys_addr_t size
, pgprot_t prot
)
290 if (virt
< VMALLOC_START
) {
291 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
296 return __create_mapping(&init_mm
, pgd_offset_k(virt
& PAGE_MASK
),
297 phys
, virt
, size
, prot
, late_alloc
);
300 #ifdef CONFIG_DEBUG_RODATA
301 static void __init
__map_memblock(phys_addr_t start
, phys_addr_t end
)
304 * Set up the executable regions using the existing section mappings
305 * for now. This will get more fine grained later once all memory
308 unsigned long kernel_x_start
= round_down(__pa(_stext
), SECTION_SIZE
);
309 unsigned long kernel_x_end
= round_up(__pa(__init_end
), SECTION_SIZE
);
311 if (end
< kernel_x_start
) {
312 create_mapping(start
, __phys_to_virt(start
),
313 end
- start
, PAGE_KERNEL
);
314 } else if (start
>= kernel_x_end
) {
315 create_mapping(start
, __phys_to_virt(start
),
316 end
- start
, PAGE_KERNEL
);
318 if (start
< kernel_x_start
)
319 create_mapping(start
, __phys_to_virt(start
),
320 kernel_x_start
- start
,
322 create_mapping(kernel_x_start
,
323 __phys_to_virt(kernel_x_start
),
324 kernel_x_end
- kernel_x_start
,
326 if (kernel_x_end
< end
)
327 create_mapping(kernel_x_end
,
328 __phys_to_virt(kernel_x_end
),
335 static void __init
__map_memblock(phys_addr_t start
, phys_addr_t end
)
337 create_mapping(start
, __phys_to_virt(start
), end
- start
,
342 static void __init
map_mem(void)
344 struct memblock_region
*reg
;
348 * Temporarily limit the memblock range. We need to do this as
349 * create_mapping requires puds, pmds and ptes to be allocated from
350 * memory addressable from the initial direct kernel mapping.
352 * The initial direct kernel mapping, located at swapper_pg_dir, gives
353 * us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
354 * PHYS_OFFSET (which must be aligned to 2MB as per
355 * Documentation/arm64/booting.txt).
357 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES
))
358 limit
= PHYS_OFFSET
+ PMD_SIZE
;
360 limit
= PHYS_OFFSET
+ PUD_SIZE
;
361 memblock_set_current_limit(limit
);
363 /* map all the memory banks */
364 for_each_memblock(memory
, reg
) {
365 phys_addr_t start
= reg
->base
;
366 phys_addr_t end
= start
+ reg
->size
;
371 #ifndef CONFIG_ARM64_64K_PAGES
373 * For the first memory bank align the start address and
374 * current memblock limit to prevent create_mapping() from
375 * allocating pte page tables from unmapped memory.
376 * When 64K pages are enabled, the pte page table for the
377 * first PGDIR_SIZE is already present in swapper_pg_dir.
380 start
= ALIGN(start
, PMD_SIZE
);
382 limit
= end
& PMD_MASK
;
383 memblock_set_current_limit(limit
);
386 __map_memblock(start
, end
);
389 /* Limit no longer required. */
390 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE
);
393 void __init
fixup_executable(void)
395 #ifdef CONFIG_DEBUG_RODATA
396 /* now that we are actually fully mapped, make the start/end more fine grained */
397 if (!IS_ALIGNED((unsigned long)_stext
, SECTION_SIZE
)) {
398 unsigned long aligned_start
= round_down(__pa(_stext
),
401 create_mapping(aligned_start
, __phys_to_virt(aligned_start
),
402 __pa(_stext
) - aligned_start
,
406 if (!IS_ALIGNED((unsigned long)__init_end
, SECTION_SIZE
)) {
407 unsigned long aligned_end
= round_up(__pa(__init_end
),
409 create_mapping(__pa(__init_end
), (unsigned long)__init_end
,
410 aligned_end
- __pa(__init_end
),
416 #ifdef CONFIG_DEBUG_RODATA
417 void mark_rodata_ro(void)
419 create_mapping_late(__pa(_stext
), (unsigned long)_stext
,
420 (unsigned long)_etext
- (unsigned long)_stext
,
421 PAGE_KERNEL_EXEC
| PTE_RDONLY
);
426 void fixup_init(void)
428 create_mapping_late(__pa(__init_begin
), (unsigned long)__init_begin
,
429 (unsigned long)__init_end
- (unsigned long)__init_begin
,
434 * paging_init() sets up the page tables, initialises the zone memory
435 * maps and sets up the zero page.
437 void __init
paging_init(void)
444 /* allocate the zero page. */
445 zero_page
= early_alloc(PAGE_SIZE
);
449 empty_zero_page
= virt_to_page(zero_page
);
452 * TTBR0 is only used for the identity mapping at this stage. Make it
453 * point to zero page to avoid speculatively fetching new entries.
455 cpu_set_reserved_ttbr0();
460 * Enable the identity mapping to allow the MMU disabling.
462 void setup_mm_for_reboot(void)
464 cpu_switch_mm(idmap_pg_dir
, &init_mm
);
469 * Check whether a kernel address is valid (derived from arch/x86/).
471 int kern_addr_valid(unsigned long addr
)
478 if ((((long)addr
) >> VA_BITS
) != -1UL)
481 pgd
= pgd_offset_k(addr
);
485 pud
= pud_offset(pgd
, addr
);
490 return pfn_valid(pud_pfn(*pud
));
492 pmd
= pmd_offset(pud
, addr
);
497 return pfn_valid(pmd_pfn(*pmd
));
499 pte
= pte_offset_kernel(pmd
, addr
);
503 return pfn_valid(pte_pfn(*pte
));
505 #ifdef CONFIG_SPARSEMEM_VMEMMAP
506 #ifdef CONFIG_ARM64_64K_PAGES
507 int __meminit
vmemmap_populate(unsigned long start
, unsigned long end
, int node
)
509 return vmemmap_populate_basepages(start
, end
, node
);
511 #else /* !CONFIG_ARM64_64K_PAGES */
512 int __meminit
vmemmap_populate(unsigned long start
, unsigned long end
, int node
)
514 unsigned long addr
= start
;
521 next
= pmd_addr_end(addr
, end
);
523 pgd
= vmemmap_pgd_populate(addr
, node
);
527 pud
= vmemmap_pud_populate(pgd
, addr
, node
);
531 pmd
= pmd_offset(pud
, addr
);
532 if (pmd_none(*pmd
)) {
535 p
= vmemmap_alloc_block_buf(PMD_SIZE
, node
);
539 set_pmd(pmd
, __pmd(__pa(p
) | PROT_SECT_NORMAL
));
541 vmemmap_verify((pte_t
*)pmd
, node
, addr
, next
);
542 } while (addr
= next
, addr
!= end
);
546 #endif /* CONFIG_ARM64_64K_PAGES */
547 void vmemmap_free(unsigned long start
, unsigned long end
)
550 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
552 static pte_t bm_pte
[PTRS_PER_PTE
] __page_aligned_bss
;
553 #if CONFIG_ARM64_PGTABLE_LEVELS > 2
554 static pmd_t bm_pmd
[PTRS_PER_PMD
] __page_aligned_bss
;
556 #if CONFIG_ARM64_PGTABLE_LEVELS > 3
557 static pud_t bm_pud
[PTRS_PER_PUD
] __page_aligned_bss
;
560 static inline pud_t
* fixmap_pud(unsigned long addr
)
562 pgd_t
*pgd
= pgd_offset_k(addr
);
564 BUG_ON(pgd_none(*pgd
) || pgd_bad(*pgd
));
566 return pud_offset(pgd
, addr
);
569 static inline pmd_t
* fixmap_pmd(unsigned long addr
)
571 pud_t
*pud
= fixmap_pud(addr
);
573 BUG_ON(pud_none(*pud
) || pud_bad(*pud
));
575 return pmd_offset(pud
, addr
);
578 static inline pte_t
* fixmap_pte(unsigned long addr
)
580 pmd_t
*pmd
= fixmap_pmd(addr
);
582 BUG_ON(pmd_none(*pmd
) || pmd_bad(*pmd
));
584 return pte_offset_kernel(pmd
, addr
);
587 void __init
early_fixmap_init(void)
592 unsigned long addr
= FIXADDR_START
;
594 pgd
= pgd_offset_k(addr
);
595 pgd_populate(&init_mm
, pgd
, bm_pud
);
596 pud
= pud_offset(pgd
, addr
);
597 pud_populate(&init_mm
, pud
, bm_pmd
);
598 pmd
= pmd_offset(pud
, addr
);
599 pmd_populate_kernel(&init_mm
, pmd
, bm_pte
);
602 * The boot-ioremap range spans multiple pmds, for which
603 * we are not preparted:
605 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN
) >> PMD_SHIFT
)
606 != (__fix_to_virt(FIX_BTMAP_END
) >> PMD_SHIFT
));
608 if ((pmd
!= fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN
)))
609 || pmd
!= fixmap_pmd(fix_to_virt(FIX_BTMAP_END
))) {
611 pr_warn("pmd %p != %p, %p\n",
612 pmd
, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN
)),
613 fixmap_pmd(fix_to_virt(FIX_BTMAP_END
)));
614 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
615 fix_to_virt(FIX_BTMAP_BEGIN
));
616 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n",
617 fix_to_virt(FIX_BTMAP_END
));
619 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END
);
620 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN
);
624 void __set_fixmap(enum fixed_addresses idx
,
625 phys_addr_t phys
, pgprot_t flags
)
627 unsigned long addr
= __fix_to_virt(idx
);
630 if (idx
>= __end_of_fixed_addresses
) {
635 pte
= fixmap_pte(addr
);
637 if (pgprot_val(flags
)) {
638 set_pte(pte
, pfn_pte(phys
>> PAGE_SHIFT
, flags
));
640 pte_clear(&init_mm
, addr
, pte
);
641 flush_tlb_kernel_range(addr
, addr
+PAGE_SIZE
);
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