arch/m68k/mm/motorola.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/arch/m68k/mm/motorola.c
   4  *
   5  * Routines specific to the Motorola MMU, originally from:
   6  * linux/arch/m68k/init.c
   7  * which are Copyright (C) 1995 Hamish Macdonald
   8  *
   9  * Moved 8/20/1999 Sam Creasey
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/signal.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/swap.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/types.h>
  20 #include <linux/init.h>
  21 #include <linux/memblock.h>
  22 #include <linux/gfp.h>
  23
  24 #include <asm/setup.h>
  25 #include <linux/uaccess.h>
  26 #include <asm/page.h>
  27 #include <asm/pgalloc.h>
  28 #include <asm/machdep.h>
  29 #include <asm/io.h>
  30 #include <asm/dma.h>
  31 #ifdef CONFIG_ATARI
  32 #include <asm/atari_stram.h>
  33 #endif
  34 #include <asm/sections.h>
  35
  36 #undef DEBUG
  37
  38 #ifndef mm_cachebits
  39 /*
  40  * Bits to add to page descriptors for "normal" caching mode.
  41  * For 68020/030 this is 0.
  42  * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
  43  */
  44 unsigned long mm_cachebits;
  45 EXPORT_SYMBOL(mm_cachebits);
  46 #endif
  47
  48 /* Prior to calling these routines, the page should have been flushed
  49  * from both the cache and ATC, or the CPU might not notice that the
  50  * cache setting for the page has been changed. -jskov
  51  */
  52 static inline void nocache_page(void *vaddr)
  53 {
  54         unsigned long addr = (unsigned long)vaddr;
  55
  56         if (CPU_IS_040_OR_060) {
  57                 pte_t *ptep = virt_to_kpte(addr);
  58
  59                 *ptep = pte_mknocache(*ptep);
  60         }
  61 }
  62
  63 static inline void cache_page(void *vaddr)
  64 {
  65         unsigned long addr = (unsigned long)vaddr;
  66
  67         if (CPU_IS_040_OR_060) {
  68                 pte_t *ptep = virt_to_kpte(addr);
  69
  70                 *ptep = pte_mkcache(*ptep);
  71         }
  72 }
  73
  74 /*
  75  * Motorola 680x0 user's manual recommends using uncached memory for address
  76  * translation tables.
  77  *
  78  * Seeing how the MMU can be external on (some of) these chips, that seems like
  79  * a very important recommendation to follow. Provide some helpers to combat
  80  * 'variation' amongst the users of this.
  81  */
  82
  83 void mmu_page_ctor(void *page)
  84 {
  85         __flush_page_to_ram(page);
  86         flush_tlb_kernel_page(page);
  87         nocache_page(page);
  88 }
  89
  90 void mmu_page_dtor(void *page)
  91 {
  92         cache_page(page);
  93 }
  94
  95 /* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
  96    struct page instead of separately kmalloced struct.  Stolen from
  97    arch/sparc/mm/srmmu.c ... */
  98
  99 typedef struct list_head ptable_desc;
 100
 101 static struct list_head ptable_list[2] = {
 102         LIST_HEAD_INIT(ptable_list[0]),
 103         LIST_HEAD_INIT(ptable_list[1]),
 104 };
 105
 106 #define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
 107 #define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
 108 #define PD_MARKBITS(dp) (*(unsigned int *)&PD_PAGE(dp)->index)
 109
 110 static const int ptable_shift[2] = {
 111         7+2, /* PGD, PMD */
 112         6+2, /* PTE */
 113 };
 114
 115 #define ptable_size(type) (1U << ptable_shift[type])
 116 #define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
 117
 118 void __init init_pointer_table(void *table, int type)
 119 {
 120         ptable_desc *dp;
 121         unsigned long ptable = (unsigned long)table;
 122         unsigned long page = ptable & PAGE_MASK;
 123         unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
 124
 125         dp = PD_PTABLE(page);
 126         if (!(PD_MARKBITS(dp) & mask)) {
 127                 PD_MARKBITS(dp) = ptable_mask(type);
 128                 list_add(dp, &ptable_list[type]);
 129         }
 130
 131         PD_MARKBITS(dp) &= ~mask;
 132         pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
 133
 134         /* unreserve the page so it's possible to free that page */
 135         __ClearPageReserved(PD_PAGE(dp));
 136         init_page_count(PD_PAGE(dp));
 137
 138         return;
 139 }
 140
 141 void *get_pointer_table(int type)
 142 {
 143         ptable_desc *dp = ptable_list[type].next;
 144         unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
 145         unsigned int tmp, off;
 146
 147         /*
 148          * For a pointer table for a user process address space, a
 149          * table is taken from a page allocated for the purpose.  Each
 150          * page can hold 8 pointer tables.  The page is remapped in
 151          * virtual address space to be noncacheable.
 152          */
 153         if (mask == 0) {
 154                 void *page;
 155                 ptable_desc *new;
 156
 157                 if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
 158                         return NULL;
 159
 160                 if (type == TABLE_PTE) {
 161                         /*
 162                          * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
 163                          * SMP.
 164                          */
 165                         pgtable_pte_page_ctor(virt_to_page(page));
 166                 }
 167
 168                 mmu_page_ctor(page);
 169
 170                 new = PD_PTABLE(page);
 171                 PD_MARKBITS(new) = ptable_mask(type) - 1;
 172                 list_add_tail(new, dp);
 173
 174                 return (pmd_t *)page;
 175         }
 176
 177         for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
 178                 ;
 179         PD_MARKBITS(dp) = mask & ~tmp;
 180         if (!PD_MARKBITS(dp)) {
 181                 /* move to end of list */
 182                 list_move_tail(dp, &ptable_list[type]);
 183         }
 184         return page_address(PD_PAGE(dp)) + off;
 185 }
 186
 187 int free_pointer_table(void *table, int type)
 188 {
 189         ptable_desc *dp;
 190         unsigned long ptable = (unsigned long)table;
 191         unsigned long page = ptable & PAGE_MASK;
 192         unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
 193
 194         dp = PD_PTABLE(page);
 195         if (PD_MARKBITS (dp) & mask)
 196                 panic ("table already free!");
 197
 198         PD_MARKBITS (dp) |= mask;
 199
 200         if (PD_MARKBITS(dp) == ptable_mask(type)) {
 201                 /* all tables in page are free, free page */
 202                 list_del(dp);
 203                 mmu_page_dtor((void *)page);
 204                 if (type == TABLE_PTE)
 205                         pgtable_pte_page_dtor(virt_to_page(page));
 206                 free_page (page);
 207                 return 1;
 208         } else if (ptable_list[type].next != dp) {
 209                 /*
 210                  * move this descriptor to the front of the list, since
 211                  * it has one or more free tables.
 212                  */
 213                 list_move(dp, &ptable_list[type]);
 214         }
 215         return 0;
 216 }
 217
 218 /* size of memory already mapped in head.S */
 219 extern __initdata unsigned long m68k_init_mapped_size;
 220
 221 extern unsigned long availmem;
 222
 223 static pte_t *last_pte_table __initdata = NULL;
 224
 225 static pte_t * __init kernel_page_table(void)
 226 {
 227         pte_t *pte_table = last_pte_table;
 228
 229         if (PAGE_ALIGNED(last_pte_table)) {
 230                 pte_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
 231                 if (!pte_table) {
 232                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 233                                         __func__, PAGE_SIZE, PAGE_SIZE);
 234                 }
 235
 236                 clear_page(pte_table);
 237                 mmu_page_ctor(pte_table);
 238
 239                 last_pte_table = pte_table;
 240         }
 241
 242         last_pte_table += PTRS_PER_PTE;
 243
 244         return pte_table;
 245 }
 246
 247 static pmd_t *last_pmd_table __initdata = NULL;
 248
 249 static pmd_t * __init kernel_ptr_table(void)
 250 {
 251         if (!last_pmd_table) {
 252                 unsigned long pmd, last;
 253                 int i;
 254
 255                 /* Find the last ptr table that was used in head.S and
 256                  * reuse the remaining space in that page for further
 257                  * ptr tables.
 258                  */
 259                 last = (unsigned long)kernel_pg_dir;
 260                 for (i = 0; i < PTRS_PER_PGD; i++) {
 261                         pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
 262
 263                         if (!pud_present(*pud))
 264                                 continue;
 265                         pmd = pgd_page_vaddr(kernel_pg_dir[i]);
 266                         if (pmd > last)
 267                                 last = pmd;
 268                 }
 269
 270                 last_pmd_table = (pmd_t *)last;
 271 #ifdef DEBUG
 272                 printk("kernel_ptr_init: %p\n", last_pmd_table);
 273 #endif
 274         }
 275
 276         last_pmd_table += PTRS_PER_PMD;
 277         if (PAGE_ALIGNED(last_pmd_table)) {
 278                 last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
 279                 if (!last_pmd_table)
 280                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 281                               __func__, PAGE_SIZE, PAGE_SIZE);
 282
 283                 clear_page(last_pmd_table);
 284                 mmu_page_ctor(last_pmd_table);
 285         }
 286
 287         return last_pmd_table;
 288 }
 289
 290 static void __init map_node(int node)
 291 {
 292         unsigned long physaddr, virtaddr, size;
 293         pgd_t *pgd_dir;
 294         p4d_t *p4d_dir;
 295         pud_t *pud_dir;
 296         pmd_t *pmd_dir;
 297         pte_t *pte_dir;
 298
 299         size = m68k_memory[node].size;
 300         physaddr = m68k_memory[node].addr;
 301         virtaddr = (unsigned long)phys_to_virt(physaddr);
 302         physaddr |= m68k_supervisor_cachemode |
 303                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
 304         if (CPU_IS_040_OR_060)
 305                 physaddr |= _PAGE_GLOBAL040;
 306
 307         while (size > 0) {
 308 #ifdef DEBUG
 309                 if (!(virtaddr & (PMD_SIZE-1)))
 310                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 311                                 virtaddr);
 312 #endif
 313                 pgd_dir = pgd_offset_k(virtaddr);
 314                 if (virtaddr && CPU_IS_020_OR_030) {
 315                         if (!(virtaddr & (PGDIR_SIZE-1)) &&
 316                             size >= PGDIR_SIZE) {
 317 #ifdef DEBUG
 318                                 printk ("[very early term]");
 319 #endif
 320                                 pgd_val(*pgd_dir) = physaddr;
 321                                 size -= PGDIR_SIZE;
 322                                 virtaddr += PGDIR_SIZE;
 323                                 physaddr += PGDIR_SIZE;
 324                                 continue;
 325                         }
 326                 }
 327                 p4d_dir = p4d_offset(pgd_dir, virtaddr);
 328                 pud_dir = pud_offset(p4d_dir, virtaddr);
 329                 if (!pud_present(*pud_dir)) {
 330                         pmd_dir = kernel_ptr_table();
 331 #ifdef DEBUG
 332                         printk ("[new pointer %p]", pmd_dir);
 333 #endif
 334                         pud_set(pud_dir, pmd_dir);
 335                 } else
 336                         pmd_dir = pmd_offset(pud_dir, virtaddr);
 337
 338                 if (CPU_IS_020_OR_030) {
 339                         if (virtaddr) {
 340 #ifdef DEBUG
 341                                 printk ("[early term]");
 342 #endif
 343                                 pmd_val(*pmd_dir) = physaddr;
 344                                 physaddr += PMD_SIZE;
 345                         } else {
 346                                 int i;
 347 #ifdef DEBUG
 348                                 printk ("[zero map]");
 349 #endif
 350                                 pte_dir = kernel_page_table();
 351                                 pmd_set(pmd_dir, pte_dir);
 352
 353                                 pte_val(*pte_dir++) = 0;
 354                                 physaddr += PAGE_SIZE;
 355                                 for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++)
 356                                         pte_val(*pte_dir++) = physaddr;
 357                         }
 358                         size -= PMD_SIZE;
 359                         virtaddr += PMD_SIZE;
 360                 } else {
 361                         if (!pmd_present(*pmd_dir)) {
 362 #ifdef DEBUG
 363                                 printk ("[new table]");
 364 #endif
 365                                 pte_dir = kernel_page_table();
 366                                 pmd_set(pmd_dir, pte_dir);
 367                         }
 368                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 369
 370                         if (virtaddr) {
 371                                 if (!pte_present(*pte_dir))
 372                                         pte_val(*pte_dir) = physaddr;
 373                         } else
 374                                 pte_val(*pte_dir) = 0;
 375                         size -= PAGE_SIZE;
 376                         virtaddr += PAGE_SIZE;
 377                         physaddr += PAGE_SIZE;
 378                 }
 379
 380         }
 381 #ifdef DEBUG
 382         printk("\n");
 383 #endif
 384 }
 385
 386 /*
 387  * paging_init() continues the virtual memory environment setup which
 388  * was begun by the code in arch/head.S.
 389  */
 390 void __init paging_init(void)
 391 {
 392         unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
 393         unsigned long min_addr, max_addr;
 394         unsigned long addr;
 395         int i;
 396
 397 #ifdef DEBUG
 398         printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
 399 #endif
 400
 401         /* Fix the cache mode in the page descriptors for the 680[46]0.  */
 402         if (CPU_IS_040_OR_060) {
 403                 int i;
 404 #ifndef mm_cachebits
 405                 mm_cachebits = _PAGE_CACHE040;
 406 #endif
 407                 for (i = 0; i < 16; i++)
 408                         pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
 409         }
 410
 411         min_addr = m68k_memory[0].addr;
 412         max_addr = min_addr + m68k_memory[0].size;
 413         memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0);
 414         for (i = 1; i < m68k_num_memory;) {
 415                 if (m68k_memory[i].addr < min_addr) {
 416                         printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
 417                                 m68k_memory[i].addr, m68k_memory[i].size);
 418                         printk("Fix your bootloader or use a memfile to make use of this area!\n");
 419                         m68k_num_memory--;
 420                         memmove(m68k_memory + i, m68k_memory + i + 1,
 421                                 (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
 422                         continue;
 423                 }
 424                 memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i);
 425                 addr = m68k_memory[i].addr + m68k_memory[i].size;
 426                 if (addr > max_addr)
 427                         max_addr = addr;
 428                 i++;
 429         }
 430         m68k_memoffset = min_addr - PAGE_OFFSET;
 431         m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
 432
 433         module_fixup(NULL, __start_fixup, __stop_fixup);
 434         flush_icache();
 435
 436         high_memory = phys_to_virt(max_addr);
 437
 438         min_low_pfn = availmem >> PAGE_SHIFT;
 439         max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT;
 440
 441         /* Reserve kernel text/data/bss and the memory allocated in head.S */
 442         memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
 443
 444         /*
 445          * Map the physical memory available into the kernel virtual
 446          * address space. Make sure memblock will not try to allocate
 447          * pages beyond the memory we already mapped in head.S
 448          */
 449         memblock_set_bottom_up(true);
 450
 451         for (i = 0; i < m68k_num_memory; i++) {
 452                 m68k_setup_node(i);
 453                 map_node(i);
 454         }
 455
 456         flush_tlb_all();
 457
 458         /*
 459          * initialize the bad page table and bad page to point
 460          * to a couple of allocated pages
 461          */
 462         empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 463         if (!empty_zero_page)
 464                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 465                       __func__, PAGE_SIZE, PAGE_SIZE);
 466
 467         /*
 468          * Set up SFC/DFC registers
 469          */
 470         set_fs(KERNEL_DS);
 471
 472 #ifdef DEBUG
 473         printk ("before free_area_init\n");
 474 #endif
 475         for (i = 0; i < m68k_num_memory; i++)
 476                 if (node_present_pages(i))
 477                         node_set_state(i, N_NORMAL_MEMORY);
 478
 479         max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM();
 480         free_area_init(max_zone_pfn);
 481 }