arch/unicore32/mm/mmu.c

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This source file includes following definitions.
noalign_setup
adjust_cr
get_mem_type
build_mem_type_table
early_pte_alloc
alloc_init_pte
alloc_init_section
create_mapping
early_vmalloc
sanity_check_meminfo
prepare_page_table
uc32_mm_memblock_reserve
devicemaps_init
map_lowmem
paging_init
setup_mm_for_reboot
update_mmu_cache
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/arch/unicore32/mm/mmu.c
   4  *
   5  * Code specific to PKUnity SoC and UniCore ISA
   6  *
   7  * Copyright (C) 2001-2010 GUAN Xue-tao
   8  */
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/init.h>
  13 #include <linux/mman.h>
  14 #include <linux/nodemask.h>
  15 #include <linux/memblock.h>
  16 #include <linux/fs.h>
  17 #include <linux/io.h>
  18 
  19 #include <asm/cputype.h>
  20 #include <asm/sections.h>
  21 #include <asm/setup.h>
  22 #include <linux/sizes.h>
  23 #include <asm/tlb.h>
  24 #include <asm/memblock.h>
  25 
  26 #include <mach/map.h>
  27 
  28 #include "mm.h"
  29 
  30 /*
  31  * empty_zero_page is a special page that is used for
  32  * zero-initialized data and COW.
  33  */
  34 struct page *empty_zero_page;
  35 EXPORT_SYMBOL(empty_zero_page);
  36 
  37 /*
  38  * The pmd table for the upper-most set of pages.
  39  */
  40 pmd_t *top_pmd;
  41 
  42 pgprot_t pgprot_user;
  43 EXPORT_SYMBOL(pgprot_user);
  44 
  45 pgprot_t pgprot_kernel;
  46 EXPORT_SYMBOL(pgprot_kernel);
  47 
  48 static int __init noalign_setup(char *__unused)
  49 {
  50         cr_alignment &= ~CR_A;
  51         cr_no_alignment &= ~CR_A;
  52         set_cr(cr_alignment);
  53         return 1;
  54 }
  55 __setup("noalign", noalign_setup);
  56 
  57 void adjust_cr(unsigned long mask, unsigned long set)
  58 {
  59         unsigned long flags;
  60 
  61         mask &= ~CR_A;
  62 
  63         set &= mask;
  64 
  65         local_irq_save(flags);
  66 
  67         cr_no_alignment = (cr_no_alignment & ~mask) | set;
  68         cr_alignment = (cr_alignment & ~mask) | set;
  69 
  70         set_cr((get_cr() & ~mask) | set);
  71 
  72         local_irq_restore(flags);
  73 }
  74 
  75 struct map_desc {
  76         unsigned long virtual;
  77         unsigned long pfn;
  78         unsigned long length;
  79         unsigned int type;
  80 };
  81 
  82 #define PROT_PTE_DEVICE         (PTE_PRESENT | PTE_YOUNG |      \
  83                                 PTE_DIRTY | PTE_READ | PTE_WRITE)
  84 #define PROT_SECT_DEVICE        (PMD_TYPE_SECT | PMD_PRESENT |  \
  85                                 PMD_SECT_READ | PMD_SECT_WRITE)
  86 
  87 static struct mem_type mem_types[] = {
  88         [MT_DEVICE] = {           /* Strongly ordered */
  89                 .prot_pte       = PROT_PTE_DEVICE,
  90                 .prot_l1        = PMD_TYPE_TABLE | PMD_PRESENT,
  91                 .prot_sect      = PROT_SECT_DEVICE,
  92         },
  93         /*
  94          * MT_KUSER: pte for vecpage -- cacheable,
  95          *       and sect for unigfx mmap -- noncacheable
  96          */
  97         [MT_KUSER] = {
  98                 .prot_pte  = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
  99                                 PTE_CACHEABLE | PTE_READ | PTE_EXEC,
 100                 .prot_l1   = PMD_TYPE_TABLE | PMD_PRESENT,
 101                 .prot_sect = PROT_SECT_DEVICE,
 102         },
 103         [MT_HIGH_VECTORS] = {
 104                 .prot_pte  = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
 105                                 PTE_CACHEABLE | PTE_READ | PTE_WRITE |
 106                                 PTE_EXEC,
 107                 .prot_l1   = PMD_TYPE_TABLE | PMD_PRESENT,
 108         },
 109         [MT_MEMORY] = {
 110                 .prot_pte  = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
 111                                 PTE_WRITE | PTE_EXEC,
 112                 .prot_l1   = PMD_TYPE_TABLE | PMD_PRESENT,
 113                 .prot_sect = PMD_TYPE_SECT | PMD_PRESENT | PMD_SECT_CACHEABLE |
 114                                 PMD_SECT_READ | PMD_SECT_WRITE | PMD_SECT_EXEC,
 115         },
 116         [MT_ROM] = {
 117                 .prot_sect = PMD_TYPE_SECT | PMD_PRESENT | PMD_SECT_CACHEABLE |
 118                                 PMD_SECT_READ,
 119         },
 120 };
 121 
 122 const struct mem_type *get_mem_type(unsigned int type)
 123 {
 124         return type < ARRAY_SIZE(mem_types) ? &mem_types[type] : NULL;
 125 }
 126 EXPORT_SYMBOL(get_mem_type);
 127 
 128 /*
 129  * Adjust the PMD section entries according to the CPU in use.
 130  */
 131 static void __init build_mem_type_table(void)
 132 {
 133         pgprot_user   = __pgprot(PTE_PRESENT | PTE_YOUNG | PTE_CACHEABLE);
 134         pgprot_kernel = __pgprot(PTE_PRESENT | PTE_YOUNG |
 135                                  PTE_DIRTY | PTE_READ | PTE_WRITE |
 136                                  PTE_EXEC | PTE_CACHEABLE);
 137 }
 138 
 139 #define vectors_base()  (vectors_high() ? 0xffff0000 : 0)
 140 
 141 static pte_t * __init early_pte_alloc(pmd_t *pmd, unsigned long addr,
 142                 unsigned long prot)
 143 {
 144         if (pmd_none(*pmd)) {
 145                 size_t size = PTRS_PER_PTE * sizeof(pte_t);
 146                 pte_t *pte = memblock_alloc(size, size);
 147 
 148                 if (!pte)
 149                         panic("%s: Failed to allocate %zu bytes align=%zx\n",
 150                               __func__, size, size);
 151 
 152                 __pmd_populate(pmd, __pa(pte) | prot);
 153         }
 154         BUG_ON(pmd_bad(*pmd));
 155         return pte_offset_kernel(pmd, addr);
 156 }
 157 
 158 static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
 159                                   unsigned long end, unsigned long pfn,
 160                                   const struct mem_type *type)
 161 {
 162         pte_t *pte = early_pte_alloc(pmd, addr, type->prot_l1);
 163         do {
 164                 set_pte(pte, pfn_pte(pfn, __pgprot(type->prot_pte)));
 165                 pfn++;
 166         } while (pte++, addr += PAGE_SIZE, addr != end);
 167 }
 168 
 169 static void __init alloc_init_section(pgd_t *pgd, unsigned long addr,
 170                                       unsigned long end, unsigned long phys,
 171                                       const struct mem_type *type)
 172 {
 173         pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
 174 
 175         /*
 176          * Try a section mapping - end, addr and phys must all be aligned
 177          * to a section boundary.
 178          */
 179         if (((addr | end | phys) & ~SECTION_MASK) == 0) {
 180                 pmd_t *p = pmd;
 181 
 182                 do {
 183                         set_pmd(pmd, __pmd(phys | type->prot_sect));
 184                         phys += SECTION_SIZE;
 185                 } while (pmd++, addr += SECTION_SIZE, addr != end);
 186 
 187                 flush_pmd_entry(p);
 188         } else {
 189                 /*
 190                  * No need to loop; pte's aren't interested in the
 191                  * individual L1 entries.
 192                  */
 193                 alloc_init_pte(pmd, addr, end, __phys_to_pfn(phys), type);
 194         }
 195 }
 196 
 197 /*
 198  * Create the page directory entries and any necessary
 199  * page tables for the mapping specified by `md'.  We
 200  * are able to cope here with varying sizes and address
 201  * offsets, and we take full advantage of sections.
 202  */
 203 static void __init create_mapping(struct map_desc *md)
 204 {
 205         unsigned long phys, addr, length, end;
 206         const struct mem_type *type;
 207         pgd_t *pgd;
 208 
 209         if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
 210                 printk(KERN_WARNING "BUG: not creating mapping for "
 211                        "0x%08llx at 0x%08lx in user region\n",
 212                        __pfn_to_phys((u64)md->pfn), md->virtual);
 213                 return;
 214         }
 215 
 216         if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
 217             md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) {
 218                 printk(KERN_WARNING "BUG: mapping for 0x%08llx at 0x%08lx "
 219                        "overlaps vmalloc space\n",
 220                        __pfn_to_phys((u64)md->pfn), md->virtual);
 221         }
 222 
 223         type = &mem_types[md->type];
 224 
 225         addr = md->virtual & PAGE_MASK;
 226         phys = (unsigned long)__pfn_to_phys(md->pfn);
 227         length = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
 228 
 229         if (type->prot_l1 == 0 && ((addr | phys | length) & ~SECTION_MASK)) {
 230                 printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
 231                        "be mapped using pages, ignoring.\n",
 232                        __pfn_to_phys(md->pfn), addr);
 233                 return;
 234         }
 235 
 236         pgd = pgd_offset_k(addr);
 237         end = addr + length;
 238         do {
 239                 unsigned long next = pgd_addr_end(addr, end);
 240 
 241                 alloc_init_section(pgd, addr, next, phys, type);
 242 
 243                 phys += next - addr;
 244                 addr = next;
 245         } while (pgd++, addr != end);
 246 }
 247 
 248 static void * __initdata vmalloc_min = (void *)(VMALLOC_END - SZ_128M);
 249 
 250 /*
 251  * vmalloc=size forces the vmalloc area to be exactly 'size'
 252  * bytes. This can be used to increase (or decrease) the vmalloc
 253  * area - the default is 128m.
 254  */
 255 static int __init early_vmalloc(char *arg)
 256 {
 257         unsigned long vmalloc_reserve = memparse(arg, NULL);
 258 
 259         if (vmalloc_reserve < SZ_16M) {
 260                 vmalloc_reserve = SZ_16M;
 261                 printk(KERN_WARNING
 262                         "vmalloc area too small, limiting to %luMB\n",
 263                         vmalloc_reserve >> 20);
 264         }
 265 
 266         if (vmalloc_reserve > VMALLOC_END - (PAGE_OFFSET + SZ_32M)) {
 267                 vmalloc_reserve = VMALLOC_END - (PAGE_OFFSET + SZ_32M);
 268                 printk(KERN_WARNING
 269                         "vmalloc area is too big, limiting to %luMB\n",
 270                         vmalloc_reserve >> 20);
 271         }
 272 
 273         vmalloc_min = (void *)(VMALLOC_END - vmalloc_reserve);
 274         return 0;
 275 }
 276 early_param("vmalloc", early_vmalloc);
 277 
 278 static phys_addr_t lowmem_limit __initdata = SZ_1G;
 279 
 280 static void __init sanity_check_meminfo(void)
 281 {
 282         int i, j;
 283 
 284         lowmem_limit = __pa(vmalloc_min - 1) + 1;
 285         memblock_set_current_limit(lowmem_limit);
 286 
 287         for (i = 0, j = 0; i < meminfo.nr_banks; i++) {
 288                 struct membank *bank = &meminfo.bank[j];
 289                 *bank = meminfo.bank[i];
 290                 j++;
 291         }
 292         meminfo.nr_banks = j;
 293 }
 294 
 295 static inline void prepare_page_table(void)
 296 {
 297         unsigned long addr;
 298         phys_addr_t end;
 299 
 300         /*
 301          * Clear out all the mappings below the kernel image.
 302          */
 303         for (addr = 0; addr < MODULES_VADDR; addr += PGDIR_SIZE)
 304                 pmd_clear(pmd_off_k(addr));
 305 
 306         for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
 307                 pmd_clear(pmd_off_k(addr));
 308 
 309         /*
 310          * Find the end of the first block of lowmem.
 311          */
 312         end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
 313         if (end >= lowmem_limit)
 314                 end = lowmem_limit;
 315 
 316         /*
 317          * Clear out all the kernel space mappings, except for the first
 318          * memory bank, up to the end of the vmalloc region.
 319          */
 320         for (addr = __phys_to_virt(end);
 321              addr < VMALLOC_END; addr += PGDIR_SIZE)
 322                 pmd_clear(pmd_off_k(addr));
 323 }
 324 
 325 /*
 326  * Reserve the special regions of memory
 327  */
 328 void __init uc32_mm_memblock_reserve(void)
 329 {
 330         /*
 331          * Reserve the page tables.  These are already in use,
 332          * and can only be in node 0.
 333          */
 334         memblock_reserve(__pa(swapper_pg_dir), PTRS_PER_PGD * sizeof(pgd_t));
 335 }
 336 
 337 /*
 338  * Set up device the mappings.  Since we clear out the page tables for all
 339  * mappings above VMALLOC_END, we will remove any debug device mappings.
 340  * This means you have to be careful how you debug this function, or any
 341  * called function.  This means you can't use any function or debugging
 342  * method which may touch any device, otherwise the kernel _will_ crash.
 343  */
 344 static void __init devicemaps_init(void)
 345 {
 346         struct map_desc map;
 347         unsigned long addr;
 348         void *vectors;
 349 
 350         /*
 351          * Allocate the vector page early.
 352          */
 353         vectors = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 354         if (!vectors)
 355                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 356                       __func__, PAGE_SIZE, PAGE_SIZE);
 357 
 358         for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
 359                 pmd_clear(pmd_off_k(addr));
 360 
 361         /*
 362          * Create a mapping for the machine vectors at the high-vectors
 363          * location (0xffff0000).  If we aren't using high-vectors, also
 364          * create a mapping at the low-vectors virtual address.
 365          */
 366         map.pfn = __phys_to_pfn(virt_to_phys(vectors));
 367         map.virtual = VECTORS_BASE;
 368         map.length = PAGE_SIZE;
 369         map.type = MT_HIGH_VECTORS;
 370         create_mapping(&map);
 371 
 372         /*
 373          * Create a mapping for the kuser page at the special
 374          * location (0xbfff0000) to the same vectors location.
 375          */
 376         map.pfn = __phys_to_pfn(virt_to_phys(vectors));
 377         map.virtual = KUSER_VECPAGE_BASE;
 378         map.length = PAGE_SIZE;
 379         map.type = MT_KUSER;
 380         create_mapping(&map);
 381 
 382         /*
 383          * Finally flush the caches and tlb to ensure that we're in a
 384          * consistent state wrt the writebuffer.  This also ensures that
 385          * any write-allocated cache lines in the vector page are written
 386          * back.  After this point, we can start to touch devices again.
 387          */
 388         local_flush_tlb_all();
 389         flush_cache_all();
 390 }
 391 
 392 static void __init map_lowmem(void)
 393 {
 394         struct memblock_region *reg;
 395 
 396         /* Map all the lowmem memory banks. */
 397         for_each_memblock(memory, reg) {
 398                 phys_addr_t start = reg->base;
 399                 phys_addr_t end = start + reg->size;
 400                 struct map_desc map;
 401 
 402                 if (end > lowmem_limit)
 403                         end = lowmem_limit;
 404                 if (start >= end)
 405                         break;
 406 
 407                 map.pfn = __phys_to_pfn(start);
 408                 map.virtual = __phys_to_virt(start);
 409                 map.length = end - start;
 410                 map.type = MT_MEMORY;
 411 
 412                 create_mapping(&map);
 413         }
 414 }
 415 
 416 /*
 417  * paging_init() sets up the page tables, initialises the zone memory
 418  * maps, and sets up the zero page, bad page and bad page tables.
 419  */
 420 void __init paging_init(void)
 421 {
 422         void *zero_page;
 423 
 424         build_mem_type_table();
 425         sanity_check_meminfo();
 426         prepare_page_table();
 427         map_lowmem();
 428         devicemaps_init();
 429 
 430         top_pmd = pmd_off_k(0xffff0000);
 431 
 432         /* allocate the zero page. */
 433         zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 434         if (!zero_page)
 435                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 436                       __func__, PAGE_SIZE, PAGE_SIZE);
 437 
 438         bootmem_init();
 439 
 440         empty_zero_page = virt_to_page(zero_page);
 441         __flush_dcache_page(NULL, empty_zero_page);
 442 }
 443 
 444 /*
 445  * In order to soft-boot, we need to insert a 1:1 mapping in place of
 446  * the user-mode pages.  This will then ensure that we have predictable
 447  * results when turning the mmu off
 448  */
 449 void setup_mm_for_reboot(void)
 450 {
 451         unsigned long base_pmdval;
 452         pgd_t *pgd;
 453         int i;
 454 
 455         /*
 456          * We need to access to user-mode page tables here. For kernel threads
 457          * we don't have any user-mode mappings so we use the context that we
 458          * "borrowed".
 459          */
 460         pgd = current->active_mm->pgd;
 461 
 462         base_pmdval = PMD_SECT_WRITE | PMD_SECT_READ | PMD_TYPE_SECT;
 463 
 464         for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++, pgd++) {
 465                 unsigned long pmdval = (i << PGDIR_SHIFT) | base_pmdval;
 466                 pmd_t *pmd;
 467 
 468                 pmd = pmd_off(pgd, i << PGDIR_SHIFT);
 469                 set_pmd(pmd, __pmd(pmdval));
 470                 flush_pmd_entry(pmd);
 471         }
 472 
 473         local_flush_tlb_all();
 474 }
 475 
 476 /*
 477  * Take care of architecture specific things when placing a new PTE into
 478  * a page table, or changing an existing PTE.  Basically, there are two
 479  * things that we need to take care of:
 480  *
 481  *  1. If PG_dcache_clean is not set for the page, we need to ensure
 482  *     that any cache entries for the kernels virtual memory
 483  *     range are written back to the page.
 484  *  2. If we have multiple shared mappings of the same space in
 485  *     an object, we need to deal with the cache aliasing issues.
 486  *
 487  * Note that the pte lock will be held.
 488  */
 489 void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
 490         pte_t *ptep)
 491 {
 492         unsigned long pfn = pte_pfn(*ptep);
 493         struct address_space *mapping;
 494         struct page *page;
 495 
 496         if (!pfn_valid(pfn))
 497                 return;
 498 
 499         /*
 500          * The zero page is never written to, so never has any dirty
 501          * cache lines, and therefore never needs to be flushed.
 502          */
 503         page = pfn_to_page(pfn);
 504         if (page == ZERO_PAGE(0))
 505                 return;
 506 
 507         mapping = page_mapping_file(page);
 508         if (!test_and_set_bit(PG_dcache_clean, &page->flags))
 509                 __flush_dcache_page(mapping, page);
 510         if (mapping)
 511                 if (vma->vm_flags & VM_EXEC)
 512                         __flush_icache_all();
 513 }
/* [<][>][^][v][top][bottom][index][help] */
root/arch/unicore32/mm/mmu.c

DEFINITIONS
