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 <asm/cputype.h>
30 #include <asm/sections.h>
31 #include <asm/setup.h>
32 #include <asm/sizes.h>
34 #include <asm/mmu_context.h>
39 * Empty_zero_page is a special page that is used for zero-initialized data
42 struct page
*empty_zero_page
;
43 EXPORT_SYMBOL(empty_zero_page
);
45 pgprot_t pgprot_default
;
46 EXPORT_SYMBOL(pgprot_default
);
48 static pmdval_t prot_sect_kernel
;
51 const char policy
[16];
56 static struct cachepolicy cache_policies
[] __initdata
= {
59 .mair
= 0x44, /* inner, outer non-cacheable */
60 .tcr
= TCR_IRGN_NC
| TCR_ORGN_NC
,
62 .policy
= "writethrough",
63 .mair
= 0xaa, /* inner, outer write-through, read-allocate */
64 .tcr
= TCR_IRGN_WT
| TCR_ORGN_WT
,
66 .policy
= "writeback",
67 .mair
= 0xee, /* inner, outer write-back, read-allocate */
68 .tcr
= TCR_IRGN_WBnWA
| TCR_ORGN_WBnWA
,
73 * These are useful for identifying cache coherency problems by allowing the
74 * cache or the cache and writebuffer to be turned off. It changes the Normal
75 * memory caching attributes in the MAIR_EL1 register.
77 static int __init
early_cachepolicy(char *p
)
82 for (i
= 0; i
< ARRAY_SIZE(cache_policies
); i
++) {
83 int len
= strlen(cache_policies
[i
].policy
);
85 if (memcmp(p
, cache_policies
[i
].policy
, len
) == 0)
88 if (i
== ARRAY_SIZE(cache_policies
)) {
89 pr_err("ERROR: unknown or unsupported cache policy: %s\n", p
);
96 * Modify MT_NORMAL attributes in MAIR_EL1.
100 " bfi %0, %1, #%2, #8\n"
101 " msr mair_el1, %0\n"
104 : "r" (cache_policies
[i
].mair
), "i" (MT_NORMAL
* 8));
107 * Modify TCR PTW cacheability attributes.
116 : "r" (cache_policies
[i
].tcr
), "r" (TCR_IRGN_MASK
| TCR_ORGN_MASK
));
122 early_param("cachepolicy", early_cachepolicy
);
125 * Adjust the PMD section entries according to the CPU in use.
127 static void __init
init_mem_pgprot(void)
129 pteval_t default_pgprot
;
132 default_pgprot
= PTE_ATTRINDX(MT_NORMAL
);
133 prot_sect_kernel
= PMD_TYPE_SECT
| PMD_SECT_AF
| PMD_ATTRINDX(MT_NORMAL
);
137 * Mark memory with the "shared" attribute for SMP systems
139 default_pgprot
|= PTE_SHARED
;
140 prot_sect_kernel
|= PMD_SECT_S
;
143 for (i
= 0; i
< 16; i
++) {
144 unsigned long v
= pgprot_val(protection_map
[i
]);
145 protection_map
[i
] = __pgprot(v
| default_pgprot
);
148 pgprot_default
= __pgprot(PTE_TYPE_PAGE
| PTE_AF
| default_pgprot
);
151 pgprot_t
phys_mem_access_prot(struct file
*file
, unsigned long pfn
,
152 unsigned long size
, pgprot_t vma_prot
)
155 return pgprot_noncached(vma_prot
);
156 else if (file
->f_flags
& O_SYNC
)
157 return pgprot_writecombine(vma_prot
);
160 EXPORT_SYMBOL(phys_mem_access_prot
);
162 static void __init
*early_alloc(unsigned long sz
)
164 void *ptr
= __va(memblock_alloc(sz
, sz
));
169 static void __init
alloc_init_pte(pmd_t
*pmd
, unsigned long addr
,
170 unsigned long end
, unsigned long pfn
)
174 if (pmd_none(*pmd
)) {
175 pte
= early_alloc(PTRS_PER_PTE
* sizeof(pte_t
));
176 __pmd_populate(pmd
, __pa(pte
), PMD_TYPE_TABLE
);
178 BUG_ON(pmd_bad(*pmd
));
180 pte
= pte_offset_kernel(pmd
, addr
);
182 set_pte(pte
, pfn_pte(pfn
, PAGE_KERNEL_EXEC
));
184 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
187 static void __init
alloc_init_pmd(pud_t
*pud
, unsigned long addr
,
188 unsigned long end
, phys_addr_t phys
)
194 * Check for initial section mappings in the pgd/pud and remove them.
196 if (pud_none(*pud
) || pud_bad(*pud
)) {
197 pmd
= early_alloc(PTRS_PER_PMD
* sizeof(pmd_t
));
198 pud_populate(&init_mm
, pud
, pmd
);
201 pmd
= pmd_offset(pud
, addr
);
203 next
= pmd_addr_end(addr
, end
);
204 /* try section mapping first */
205 if (((addr
| next
| phys
) & ~SECTION_MASK
) == 0)
206 set_pmd(pmd
, __pmd(phys
| prot_sect_kernel
));
208 alloc_init_pte(pmd
, addr
, next
, __phys_to_pfn(phys
));
210 } while (pmd
++, addr
= next
, addr
!= end
);
213 static void __init
alloc_init_pud(pgd_t
*pgd
, unsigned long addr
,
214 unsigned long end
, unsigned long phys
)
216 pud_t
*pud
= pud_offset(pgd
, addr
);
220 next
= pud_addr_end(addr
, end
);
221 alloc_init_pmd(pud
, addr
, next
, phys
);
223 } while (pud
++, addr
= next
, addr
!= end
);
227 * Create the page directory entries and any necessary page tables for the
228 * mapping specified by 'md'.
230 static void __init
create_mapping(phys_addr_t phys
, unsigned long virt
,
233 unsigned long addr
, length
, end
, next
;
236 if (virt
< VMALLOC_START
) {
237 pr_warning("BUG: not creating mapping for 0x%016llx at 0x%016lx - outside kernel range\n",
242 addr
= virt
& PAGE_MASK
;
243 length
= PAGE_ALIGN(size
+ (virt
& ~PAGE_MASK
));
245 pgd
= pgd_offset_k(addr
);
248 next
= pgd_addr_end(addr
, end
);
249 alloc_init_pud(pgd
, addr
, next
, phys
);
251 } while (pgd
++, addr
= next
, addr
!= end
);
254 static void __init
map_mem(void)
256 struct memblock_region
*reg
;
258 /* map all the memory banks */
259 for_each_memblock(memory
, reg
) {
260 phys_addr_t start
= reg
->base
;
261 phys_addr_t end
= start
+ reg
->size
;
266 create_mapping(start
, __phys_to_virt(start
), end
- start
);
271 * paging_init() sets up the page tables, initialises the zone memory
272 * maps and sets up the zero page.
274 void __init
paging_init(void)
279 * Maximum PGDIR_SIZE addressable via the initial direct kernel
280 * mapping in swapper_pg_dir.
282 memblock_set_current_limit((PHYS_OFFSET
& PGDIR_MASK
) + PGDIR_SIZE
);
288 * Finally flush the caches and tlb to ensure that we're in a
294 /* allocate the zero page. */
295 zero_page
= early_alloc(PAGE_SIZE
);
299 empty_zero_page
= virt_to_page(zero_page
);
300 __flush_dcache_page(empty_zero_page
);
303 * TTBR0 is only used for the identity mapping at this stage. Make it
304 * point to zero page to avoid speculatively fetching new entries.
306 cpu_set_reserved_ttbr0();
311 * Enable the identity mapping to allow the MMU disabling.
313 void setup_mm_for_reboot(void)
315 cpu_switch_mm(idmap_pg_dir
, &init_mm
);
320 * Check whether a kernel address is valid (derived from arch/x86/).
322 int kern_addr_valid(unsigned long addr
)
329 if ((((long)addr
) >> VA_BITS
) != -1UL)
332 pgd
= pgd_offset_k(addr
);
336 pud
= pud_offset(pgd
, addr
);
340 pmd
= pmd_offset(pud
, addr
);
344 pte
= pte_offset_kernel(pmd
, addr
);
348 return pfn_valid(pte_pfn(*pte
));
350 #ifdef CONFIG_SPARSEMEM_VMEMMAP
351 #ifdef CONFIG_ARM64_64K_PAGES
352 int __meminit
vmemmap_populate(struct page
*start_page
,
353 unsigned long size
, int node
)
355 return vmemmap_populate_basepages(start_page
, size
, node
);
357 #else /* !CONFIG_ARM64_64K_PAGES */
358 int __meminit
vmemmap_populate(struct page
*start_page
,
359 unsigned long size
, int node
)
361 unsigned long addr
= (unsigned long)start_page
;
362 unsigned long end
= (unsigned long)(start_page
+ size
);
369 next
= pmd_addr_end(addr
, end
);
371 pgd
= vmemmap_pgd_populate(addr
, node
);
375 pud
= vmemmap_pud_populate(pgd
, addr
, node
);
379 pmd
= pmd_offset(pud
, addr
);
380 if (pmd_none(*pmd
)) {
383 p
= vmemmap_alloc_block_buf(PMD_SIZE
, node
);
387 set_pmd(pmd
, __pmd(__pa(p
) | prot_sect_kernel
));
389 vmemmap_verify((pte_t
*)pmd
, node
, addr
, next
);
390 } while (addr
= next
, addr
!= end
);
394 #endif /* CONFIG_ARM64_64K_PAGES */
395 #endif /* CONFIG_SPARSEMEM_VMEMMAP */