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
);
47 const char policy
[16];
52 static struct cachepolicy cache_policies
[] __initdata
= {
55 .mair
= 0x44, /* inner, outer non-cacheable */
56 .tcr
= TCR_IRGN_NC
| TCR_ORGN_NC
,
58 .policy
= "writethrough",
59 .mair
= 0xaa, /* inner, outer write-through, read-allocate */
60 .tcr
= TCR_IRGN_WT
| TCR_ORGN_WT
,
62 .policy
= "writeback",
63 .mair
= 0xee, /* inner, outer write-back, read-allocate */
64 .tcr
= TCR_IRGN_WBnWA
| TCR_ORGN_WBnWA
,
69 * These are useful for identifying cache coherency problems by allowing the
70 * cache or the cache and writebuffer to be turned off. It changes the Normal
71 * memory caching attributes in the MAIR_EL1 register.
73 static int __init
early_cachepolicy(char *p
)
78 for (i
= 0; i
< ARRAY_SIZE(cache_policies
); i
++) {
79 int len
= strlen(cache_policies
[i
].policy
);
81 if (memcmp(p
, cache_policies
[i
].policy
, len
) == 0)
84 if (i
== ARRAY_SIZE(cache_policies
)) {
85 pr_err("ERROR: unknown or unsupported cache policy: %s\n", p
);
92 * Modify MT_NORMAL attributes in MAIR_EL1.
96 " bfi %0, %1, #%2, #8\n"
100 : "r" (cache_policies
[i
].mair
), "i" (MT_NORMAL
* 8));
103 * Modify TCR PTW cacheability attributes.
112 : "r" (cache_policies
[i
].tcr
), "r" (TCR_IRGN_MASK
| TCR_ORGN_MASK
));
118 early_param("cachepolicy", early_cachepolicy
);
120 pgprot_t
phys_mem_access_prot(struct file
*file
, unsigned long pfn
,
121 unsigned long size
, pgprot_t vma_prot
)
124 return pgprot_noncached(vma_prot
);
125 else if (file
->f_flags
& O_SYNC
)
126 return pgprot_writecombine(vma_prot
);
129 EXPORT_SYMBOL(phys_mem_access_prot
);
131 static void __init
*early_alloc(unsigned long sz
)
133 void *ptr
= __va(memblock_alloc(sz
, sz
));
138 static void __init
alloc_init_pte(pmd_t
*pmd
, unsigned long addr
,
139 unsigned long end
, unsigned long pfn
,
144 if (pmd_none(*pmd
)) {
145 pte
= early_alloc(PTRS_PER_PTE
* sizeof(pte_t
));
146 __pmd_populate(pmd
, __pa(pte
), PMD_TYPE_TABLE
);
148 BUG_ON(pmd_bad(*pmd
));
150 pte
= pte_offset_kernel(pmd
, addr
);
152 set_pte(pte
, pfn_pte(pfn
, prot
));
154 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
157 static void __init
alloc_init_pmd(pud_t
*pud
, unsigned long addr
,
158 unsigned long end
, phys_addr_t phys
,
167 prot_sect
= PROT_SECT_DEVICE_nGnRE
;
168 prot_pte
= __pgprot(PROT_DEVICE_nGnRE
);
170 prot_sect
= PROT_SECT_NORMAL_EXEC
;
171 prot_pte
= PAGE_KERNEL_EXEC
;
175 * Check for initial section mappings in the pgd/pud and remove them.
177 if (pud_none(*pud
) || pud_bad(*pud
)) {
178 pmd
= early_alloc(PTRS_PER_PMD
* sizeof(pmd_t
));
179 pud_populate(&init_mm
, pud
, pmd
);
182 pmd
= pmd_offset(pud
, addr
);
184 next
= pmd_addr_end(addr
, end
);
185 /* try section mapping first */
186 if (((addr
| next
| phys
) & ~SECTION_MASK
) == 0) {
188 set_pmd(pmd
, __pmd(phys
| prot_sect
));
190 * Check for previous table entries created during
191 * boot (__create_page_tables) and flush them.
193 if (!pmd_none(old_pmd
))
196 alloc_init_pte(pmd
, addr
, next
, __phys_to_pfn(phys
),
200 } while (pmd
++, addr
= next
, addr
!= end
);
203 static void __init
alloc_init_pud(pgd_t
*pgd
, unsigned long addr
,
204 unsigned long end
, unsigned long phys
,
207 pud_t
*pud
= pud_offset(pgd
, addr
);
211 next
= pud_addr_end(addr
, end
);
214 * For 4K granule only, attempt to put down a 1GB block
216 if (!map_io
&& (PAGE_SHIFT
== 12) &&
217 ((addr
| next
| phys
) & ~PUD_MASK
) == 0) {
218 pud_t old_pud
= *pud
;
219 set_pud(pud
, __pud(phys
| PROT_SECT_NORMAL_EXEC
));
222 * If we have an old value for a pud, it will
223 * be pointing to a pmd table that we no longer
224 * need (from swapper_pg_dir).
226 * Look up the old pmd table and free it.
228 if (!pud_none(old_pud
)) {
229 phys_addr_t table
= __pa(pmd_offset(&old_pud
, 0));
230 memblock_free(table
, PAGE_SIZE
);
234 alloc_init_pmd(pud
, addr
, next
, phys
, map_io
);
237 } while (pud
++, addr
= next
, addr
!= end
);
241 * Create the page directory entries and any necessary page tables for the
242 * mapping specified by 'md'.
244 static void __init
__create_mapping(pgd_t
*pgd
, phys_addr_t phys
,
245 unsigned long virt
, phys_addr_t size
,
248 unsigned long addr
, length
, end
, next
;
250 addr
= virt
& PAGE_MASK
;
251 length
= PAGE_ALIGN(size
+ (virt
& ~PAGE_MASK
));
255 next
= pgd_addr_end(addr
, end
);
256 alloc_init_pud(pgd
, addr
, next
, phys
, map_io
);
258 } while (pgd
++, addr
= next
, addr
!= end
);
261 static void __init
create_mapping(phys_addr_t phys
, unsigned long virt
,
264 if (virt
< VMALLOC_START
) {
265 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
269 __create_mapping(pgd_offset_k(virt
& PAGE_MASK
), phys
, virt
, size
, 0);
272 void __init
create_id_mapping(phys_addr_t addr
, phys_addr_t size
, int map_io
)
274 if ((addr
>> PGDIR_SHIFT
) >= ARRAY_SIZE(idmap_pg_dir
)) {
275 pr_warn("BUG: not creating id mapping for %pa\n", &addr
);
278 __create_mapping(&idmap_pg_dir
[pgd_index(addr
)],
279 addr
, addr
, size
, map_io
);
282 static void __init
map_mem(void)
284 struct memblock_region
*reg
;
288 * Temporarily limit the memblock range. We need to do this as
289 * create_mapping requires puds, pmds and ptes to be allocated from
290 * memory addressable from the initial direct kernel mapping.
292 * The initial direct kernel mapping, located at swapper_pg_dir,
293 * gives us PGDIR_SIZE memory starting from PHYS_OFFSET (which must be
294 * aligned to 2MB as per Documentation/arm64/booting.txt).
296 limit
= PHYS_OFFSET
+ PGDIR_SIZE
;
297 memblock_set_current_limit(limit
);
299 /* map all the memory banks */
300 for_each_memblock(memory
, reg
) {
301 phys_addr_t start
= reg
->base
;
302 phys_addr_t end
= start
+ reg
->size
;
307 #ifndef CONFIG_ARM64_64K_PAGES
309 * For the first memory bank align the start address and
310 * current memblock limit to prevent create_mapping() from
311 * allocating pte page tables from unmapped memory.
312 * When 64K pages are enabled, the pte page table for the
313 * first PGDIR_SIZE is already present in swapper_pg_dir.
316 start
= ALIGN(start
, PMD_SIZE
);
318 limit
= end
& PMD_MASK
;
319 memblock_set_current_limit(limit
);
323 create_mapping(start
, __phys_to_virt(start
), end
- start
);
326 /* Limit no longer required. */
327 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE
);
331 * paging_init() sets up the page tables, initialises the zone memory
332 * maps and sets up the zero page.
334 void __init
paging_init(void)
341 * Finally flush the caches and tlb to ensure that we're in a
347 /* allocate the zero page. */
348 zero_page
= early_alloc(PAGE_SIZE
);
352 empty_zero_page
= virt_to_page(zero_page
);
355 * TTBR0 is only used for the identity mapping at this stage. Make it
356 * point to zero page to avoid speculatively fetching new entries.
358 cpu_set_reserved_ttbr0();
363 * Enable the identity mapping to allow the MMU disabling.
365 void setup_mm_for_reboot(void)
367 cpu_switch_mm(idmap_pg_dir
, &init_mm
);
372 * Check whether a kernel address is valid (derived from arch/x86/).
374 int kern_addr_valid(unsigned long addr
)
381 if ((((long)addr
) >> VA_BITS
) != -1UL)
384 pgd
= pgd_offset_k(addr
);
388 pud
= pud_offset(pgd
, addr
);
393 return pfn_valid(pud_pfn(*pud
));
395 pmd
= pmd_offset(pud
, addr
);
400 return pfn_valid(pmd_pfn(*pmd
));
402 pte
= pte_offset_kernel(pmd
, addr
);
406 return pfn_valid(pte_pfn(*pte
));
408 #ifdef CONFIG_SPARSEMEM_VMEMMAP
409 #ifdef CONFIG_ARM64_64K_PAGES
410 int __meminit
vmemmap_populate(unsigned long start
, unsigned long end
, int node
)
412 return vmemmap_populate_basepages(start
, end
, node
);
414 #else /* !CONFIG_ARM64_64K_PAGES */
415 int __meminit
vmemmap_populate(unsigned long start
, unsigned long end
, int node
)
417 unsigned long addr
= start
;
424 next
= pmd_addr_end(addr
, end
);
426 pgd
= vmemmap_pgd_populate(addr
, node
);
430 pud
= vmemmap_pud_populate(pgd
, addr
, node
);
434 pmd
= pmd_offset(pud
, addr
);
435 if (pmd_none(*pmd
)) {
438 p
= vmemmap_alloc_block_buf(PMD_SIZE
, node
);
442 set_pmd(pmd
, __pmd(__pa(p
) | PROT_SECT_NORMAL
));
444 vmemmap_verify((pte_t
*)pmd
, node
, addr
, next
);
445 } while (addr
= next
, addr
!= end
);
449 #endif /* CONFIG_ARM64_64K_PAGES */
450 void vmemmap_free(unsigned long start
, unsigned long end
)
453 #endif /* CONFIG_SPARSEMEM_VMEMMAP */