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 #ifdef CONFIG_ATARI
  31 #include <asm/atari_stram.h>
  32 #endif
  33 #include <asm/sections.h>
  34
  35 #undef DEBUG
  36
  37 #ifndef mm_cachebits
  38 /*
  39  * Bits to add to page descriptors for "normal" caching mode.
  40  * For 68020/030 this is 0.
  41  * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
  42  */
  43 unsigned long mm_cachebits;
  44 EXPORT_SYMBOL(mm_cachebits);
  45 #endif
  46
  47 /* Prior to calling these routines, the page should have been flushed
  48  * from both the cache and ATC, or the CPU might not notice that the
  49  * cache setting for the page has been changed. -jskov
  50  */
  51 static inline void nocache_page(void *vaddr)
  52 {
  53         unsigned long addr = (unsigned long)vaddr;
  54
  55         if (CPU_IS_040_OR_060) {
  56                 pte_t *ptep = virt_to_kpte(addr);
  57
  58                 *ptep = pte_mknocache(*ptep);
  59         }
  60 }
  61
  62 static inline void cache_page(void *vaddr)
  63 {
  64         unsigned long addr = (unsigned long)vaddr;
  65
  66         if (CPU_IS_040_OR_060) {
  67                 pte_t *ptep = virt_to_kpte(addr);
  68
  69                 *ptep = pte_mkcache(*ptep);
  70         }
  71 }
  72
  73 /*
  74  * Motorola 680x0 user's manual recommends using uncached memory for address
  75  * translation tables.
  76  *
  77  * Seeing how the MMU can be external on (some of) these chips, that seems like
  78  * a very important recommendation to follow. Provide some helpers to combat
  79  * 'variation' amongst the users of this.
  80  */
  81
  82 void mmu_page_ctor(void *page)
  83 {
  84         __flush_pages_to_ram(page, 1);
  85         flush_tlb_kernel_page(page);
  86         nocache_page(page);
  87 }
  88
  89 void mmu_page_dtor(void *page)
  90 {
  91         cache_page(page);
  92 }
  93
  94 /* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
  95    struct page instead of separately kmalloced struct.  Stolen from
  96    arch/sparc/mm/srmmu.c ... */
  97
  98 typedef struct list_head ptable_desc;
  99
 100 static struct list_head ptable_list[2] = {
 101         LIST_HEAD_INIT(ptable_list[0]),
 102         LIST_HEAD_INIT(ptable_list[1]),
 103 };
 104
 105 #define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page((void *)(page))->lru))
 106 #define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
 107 #define PD_MARKBITS(dp) (*(unsigned int *)&PD_PAGE(dp)->index)
 108
 109 static const int ptable_shift[2] = {
 110         7+2, /* PGD, PMD */
 111         6+2, /* PTE */
 112 };
 113
 114 #define ptable_size(type) (1U << ptable_shift[type])
 115 #define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
 116
 117 void __init init_pointer_table(void *table, int type)
 118 {
 119         ptable_desc *dp;
 120         unsigned long ptable = (unsigned long)table;
 121         unsigned long page = ptable & PAGE_MASK;
 122         unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
 123
 124         dp = PD_PTABLE(page);
 125         if (!(PD_MARKBITS(dp) & mask)) {
 126                 PD_MARKBITS(dp) = ptable_mask(type);
 127                 list_add(dp, &ptable_list[type]);
 128         }
 129
 130         PD_MARKBITS(dp) &= ~mask;
 131         pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
 132
 133         /* unreserve the page so it's possible to free that page */
 134         __ClearPageReserved(PD_PAGE(dp));
 135         init_page_count(PD_PAGE(dp));
 136
 137         return;
 138 }
 139
 140 void *get_pointer_table(int type)
 141 {
 142         ptable_desc *dp = ptable_list[type].next;
 143         unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
 144         unsigned int tmp, off;
 145
 146         /*
 147          * For a pointer table for a user process address space, a
 148          * table is taken from a page allocated for the purpose.  Each
 149          * page can hold 8 pointer tables.  The page is remapped in
 150          * virtual address space to be noncacheable.
 151          */
 152         if (mask == 0) {
 153                 void *page;
 154                 ptable_desc *new;
 155
 156                 if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
 157                         return NULL;
 158
 159                 if (type == TABLE_PTE) {
 160                         /*
 161                          * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
 162                          * SMP.
 163                          */
 164                         pagetable_pte_ctor(virt_to_ptdesc(page));
 165                 }
 166
 167                 mmu_page_ctor(page);
 168
 169                 new = PD_PTABLE(page);
 170                 PD_MARKBITS(new) = ptable_mask(type) - 1;
 171                 list_add_tail(new, dp);
 172
 173                 return (pmd_t *)page;
 174         }
 175
 176         for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
 177                 ;
 178         PD_MARKBITS(dp) = mask & ~tmp;
 179         if (!PD_MARKBITS(dp)) {
 180                 /* move to end of list */
 181                 list_move_tail(dp, &ptable_list[type]);
 182         }
 183         return page_address(PD_PAGE(dp)) + off;
 184 }
 185
 186 int free_pointer_table(void *table, int type)
 187 {
 188         ptable_desc *dp;
 189         unsigned long ptable = (unsigned long)table;
 190         unsigned long page = ptable & PAGE_MASK;
 191         unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
 192
 193         dp = PD_PTABLE(page);
 194         if (PD_MARKBITS (dp) & mask)
 195                 panic ("table already free!");
 196
 197         PD_MARKBITS (dp) |= mask;
 198
 199         if (PD_MARKBITS(dp) == ptable_mask(type)) {
 200                 /* all tables in page are free, free page */
 201                 list_del(dp);
 202                 mmu_page_dtor((void *)page);
 203                 if (type == TABLE_PTE)
 204                         pagetable_pte_dtor(virt_to_ptdesc((void *)page));
 205                 free_page (page);
 206                 return 1;
 207         } else if (ptable_list[type].next != dp) {
 208                 /*
 209                  * move this descriptor to the front of the list, since
 210                  * it has one or more free tables.
 211                  */
 212                 list_move(dp, &ptable_list[type]);
 213         }
 214         return 0;
 215 }
 216
 217 /* size of memory already mapped in head.S */
 218 extern __initdata unsigned long m68k_init_mapped_size;
 219
 220 extern unsigned long availmem;
 221
 222 static pte_t *last_pte_table __initdata = NULL;
 223
 224 static pte_t * __init kernel_page_table(void)
 225 {
 226         pte_t *pte_table = last_pte_table;
 227
 228         if (PAGE_ALIGNED(last_pte_table)) {
 229                 pte_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
 230                 if (!pte_table) {
 231                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 232                                         __func__, PAGE_SIZE, PAGE_SIZE);
 233                 }
 234
 235                 clear_page(pte_table);
 236                 mmu_page_ctor(pte_table);
 237
 238                 last_pte_table = pte_table;
 239         }
 240
 241         last_pte_table += PTRS_PER_PTE;
 242
 243         return pte_table;
 244 }
 245
 246 static pmd_t *last_pmd_table __initdata = NULL;
 247
 248 static pmd_t * __init kernel_ptr_table(void)
 249 {
 250         if (!last_pmd_table) {
 251                 unsigned long pmd, last;
 252                 int i;
 253
 254                 /* Find the last ptr table that was used in head.S and
 255                  * reuse the remaining space in that page for further
 256                  * ptr tables.
 257                  */
 258                 last = (unsigned long)kernel_pg_dir;
 259                 for (i = 0; i < PTRS_PER_PGD; i++) {
 260                         pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
 261
 262                         if (!pud_present(*pud))
 263                                 continue;
 264                         pmd = pgd_page_vaddr(kernel_pg_dir[i]);
 265                         if (pmd > last)
 266                                 last = pmd;
 267                 }
 268
 269                 last_pmd_table = (pmd_t *)last;
 270 #ifdef DEBUG
 271                 printk("kernel_ptr_init: %p\n", last_pmd_table);
 272 #endif
 273         }
 274
 275         last_pmd_table += PTRS_PER_PMD;
 276         if (PAGE_ALIGNED(last_pmd_table)) {
 277                 last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
 278                 if (!last_pmd_table)
 279                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 280                               __func__, PAGE_SIZE, PAGE_SIZE);
 281
 282                 clear_page(last_pmd_table);
 283                 mmu_page_ctor(last_pmd_table);
 284         }
 285
 286         return last_pmd_table;
 287 }
 288
 289 static void __init map_node(int node)
 290 {
 291         unsigned long physaddr, virtaddr, size;
 292         pgd_t *pgd_dir;
 293         p4d_t *p4d_dir;
 294         pud_t *pud_dir;
 295         pmd_t *pmd_dir;
 296         pte_t *pte_dir;
 297
 298         size = m68k_memory[node].size;
 299         physaddr = m68k_memory[node].addr;
 300         virtaddr = (unsigned long)phys_to_virt(physaddr);
 301         physaddr |= m68k_supervisor_cachemode |
 302                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
 303         if (CPU_IS_040_OR_060)
 304                 physaddr |= _PAGE_GLOBAL040;
 305
 306         while (size > 0) {
 307 #ifdef DEBUG
 308                 if (!(virtaddr & (PMD_SIZE-1)))
 309                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 310                                 virtaddr);
 311 #endif
 312                 pgd_dir = pgd_offset_k(virtaddr);
 313                 if (virtaddr && CPU_IS_020_OR_030) {
 314                         if (!(virtaddr & (PGDIR_SIZE-1)) &&
 315                             size >= PGDIR_SIZE) {
 316 #ifdef DEBUG
 317                                 printk ("[very early term]");
 318 #endif
 319                                 pgd_val(*pgd_dir) = physaddr;
 320                                 size -= PGDIR_SIZE;
 321                                 virtaddr += PGDIR_SIZE;
 322                                 physaddr += PGDIR_SIZE;
 323                                 continue;
 324                         }
 325                 }
 326                 p4d_dir = p4d_offset(pgd_dir, virtaddr);
 327                 pud_dir = pud_offset(p4d_dir, virtaddr);
 328                 if (!pud_present(*pud_dir)) {
 329                         pmd_dir = kernel_ptr_table();
 330 #ifdef DEBUG
 331                         printk ("[new pointer %p]", pmd_dir);
 332 #endif
 333                         pud_set(pud_dir, pmd_dir);
 334                 } else
 335                         pmd_dir = pmd_offset(pud_dir, virtaddr);
 336
 337                 if (CPU_IS_020_OR_030) {
 338                         if (virtaddr) {
 339 #ifdef DEBUG
 340                                 printk ("[early term]");
 341 #endif
 342                                 pmd_val(*pmd_dir) = physaddr;
 343                                 physaddr += PMD_SIZE;
 344                         } else {
 345                                 int i;
 346 #ifdef DEBUG
 347                                 printk ("[zero map]");
 348 #endif
 349                                 pte_dir = kernel_page_table();
 350                                 pmd_set(pmd_dir, pte_dir);
 351
 352                                 pte_val(*pte_dir++) = 0;
 353                                 physaddr += PAGE_SIZE;
 354                                 for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++)
 355                                         pte_val(*pte_dir++) = physaddr;
 356                         }
 357                         size -= PMD_SIZE;
 358                         virtaddr += PMD_SIZE;
 359                 } else {
 360                         if (!pmd_present(*pmd_dir)) {
 361 #ifdef DEBUG
 362                                 printk ("[new table]");
 363 #endif
 364                                 pte_dir = kernel_page_table();
 365                                 pmd_set(pmd_dir, pte_dir);
 366                         }
 367                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 368
 369                         if (virtaddr) {
 370                                 if (!pte_present(*pte_dir))
 371                                         pte_val(*pte_dir) = physaddr;
 372                         } else
 373                                 pte_val(*pte_dir) = 0;
 374                         size -= PAGE_SIZE;
 375                         virtaddr += PAGE_SIZE;
 376                         physaddr += PAGE_SIZE;
 377                 }
 378
 379         }
 380 #ifdef DEBUG
 381         printk("\n");
 382 #endif
 383 }
 384
 385 /*
 386  * Alternate definitions that are compile time constants, for
 387  * initializing protection_map.  The cachebits are fixed later.
 388  */
 389 #define PAGE_NONE_C     __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
 390 #define PAGE_SHARED_C   __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
 391 #define PAGE_COPY_C     __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
 392 #define PAGE_READONLY_C __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
 393
 394 static pgprot_t protection_map[16] __ro_after_init = {
 395         [VM_NONE]                                       = PAGE_NONE_C,
 396         [VM_READ]                                       = PAGE_READONLY_C,
 397         [VM_WRITE]                                      = PAGE_COPY_C,
 398         [VM_WRITE | VM_READ]                            = PAGE_COPY_C,
 399         [VM_EXEC]                                       = PAGE_READONLY_C,
 400         [VM_EXEC | VM_READ]                             = PAGE_READONLY_C,
 401         [VM_EXEC | VM_WRITE]                            = PAGE_COPY_C,
 402         [VM_EXEC | VM_WRITE | VM_READ]                  = PAGE_COPY_C,
 403         [VM_SHARED]                                     = PAGE_NONE_C,
 404         [VM_SHARED | VM_READ]                           = PAGE_READONLY_C,
 405         [VM_SHARED | VM_WRITE]                          = PAGE_SHARED_C,
 406         [VM_SHARED | VM_WRITE | VM_READ]                = PAGE_SHARED_C,
 407         [VM_SHARED | VM_EXEC]                           = PAGE_READONLY_C,
 408         [VM_SHARED | VM_EXEC | VM_READ]                 = PAGE_READONLY_C,
 409         [VM_SHARED | VM_EXEC | VM_WRITE]                = PAGE_SHARED_C,
 410         [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = PAGE_SHARED_C
 411 };
 412 DECLARE_VM_GET_PAGE_PROT
 413
 414 /*
 415  * paging_init() continues the virtual memory environment setup which
 416  * was begun by the code in arch/head.S.
 417  */
 418 void __init paging_init(void)
 419 {
 420         unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
 421         unsigned long min_addr, max_addr;
 422         unsigned long addr;
 423         int i;
 424
 425 #ifdef DEBUG
 426         printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
 427 #endif
 428
 429         /* Fix the cache mode in the page descriptors for the 680[46]0.  */
 430         if (CPU_IS_040_OR_060) {
 431                 int i;
 432 #ifndef mm_cachebits
 433                 mm_cachebits = _PAGE_CACHE040;
 434 #endif
 435                 for (i = 0; i < 16; i++)
 436                         pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
 437         }
 438
 439         min_addr = m68k_memory[0].addr;
 440         max_addr = min_addr + m68k_memory[0].size - 1;
 441         memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
 442                           MEMBLOCK_NONE);
 443         for (i = 1; i < m68k_num_memory;) {
 444                 if (m68k_memory[i].addr < min_addr) {
 445                         printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
 446                                 m68k_memory[i].addr, m68k_memory[i].size);
 447                         printk("Fix your bootloader or use a memfile to make use of this area!\n");
 448                         m68k_num_memory--;
 449                         memmove(m68k_memory + i, m68k_memory + i + 1,
 450                                 (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
 451                         continue;
 452                 }
 453                 memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i,
 454                                   MEMBLOCK_NONE);
 455                 addr = m68k_memory[i].addr + m68k_memory[i].size - 1;
 456                 if (addr > max_addr)
 457                         max_addr = addr;
 458                 i++;
 459         }
 460         m68k_memoffset = min_addr - PAGE_OFFSET;
 461         m68k_virt_to_node_shift = fls(max_addr - min_addr) - 6;
 462
 463         module_fixup(NULL, __start_fixup, __stop_fixup);
 464         flush_icache();
 465
 466         high_memory = phys_to_virt(max_addr) + 1;
 467
 468         min_low_pfn = availmem >> PAGE_SHIFT;
 469         max_pfn = max_low_pfn = (max_addr >> PAGE_SHIFT) + 1;
 470
 471         /* Reserve kernel text/data/bss and the memory allocated in head.S */
 472         memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
 473
 474         /*
 475          * Map the physical memory available into the kernel virtual
 476          * address space. Make sure memblock will not try to allocate
 477          * pages beyond the memory we already mapped in head.S
 478          */
 479         memblock_set_bottom_up(true);
 480
 481         for (i = 0; i < m68k_num_memory; i++) {
 482                 m68k_setup_node(i);
 483                 map_node(i);
 484         }
 485
 486         flush_tlb_all();
 487
 488         early_memtest(min_addr, max_addr);
 489
 490         /*
 491          * initialize the bad page table and bad page to point
 492          * to a couple of allocated pages
 493          */
 494         empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 495         if (!empty_zero_page)
 496                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 497                       __func__, PAGE_SIZE, PAGE_SIZE);
 498
 499         /*
 500          * Set up SFC/DFC registers
 501          */
 502         set_fc(USER_DATA);
 503
 504 #ifdef DEBUG
 505         printk ("before free_area_init\n");
 506 #endif
 507         for (i = 0; i < m68k_num_memory; i++)
 508                 if (node_present_pages(i))
 509                         node_set_state(i, N_NORMAL_MEMORY);
 510
 511         max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM();
 512         free_area_init(max_zone_pfn);
 513 }