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[3] = {
 101         LIST_HEAD_INIT(ptable_list[0]),
 102         LIST_HEAD_INIT(ptable_list[1]),
 103         LIST_HEAD_INIT(ptable_list[2]),
 104 };
 105
 106 #define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page((void *)(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[3] = {
 111         7+2, /* PGD */
 112         7+2, /* PMD */
 113         6+2, /* PTE */
 114 };
 115
 116 #define ptable_size(type) (1U << ptable_shift[type])
 117 #define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
 118
 119 void __init init_pointer_table(void *table, int type)
 120 {
 121         ptable_desc *dp;
 122         unsigned long ptable = (unsigned long)table;
 123         unsigned long page = ptable & PAGE_MASK;
 124         unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
 125
 126         dp = PD_PTABLE(page);
 127         if (!(PD_MARKBITS(dp) & mask)) {
 128                 PD_MARKBITS(dp) = ptable_mask(type);
 129                 list_add(dp, &ptable_list[type]);
 130         }
 131
 132         PD_MARKBITS(dp) &= ~mask;
 133         pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
 134
 135         /* unreserve the page so it's possible to free that page */
 136         __ClearPageReserved(PD_PAGE(dp));
 137         init_page_count(PD_PAGE(dp));
 138
 139         return;
 140 }
 141
 142 void *get_pointer_table(int type)
 143 {
 144         ptable_desc *dp = ptable_list[type].next;
 145         unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
 146         unsigned int tmp, off;
 147
 148         /*
 149          * For a pointer table for a user process address space, a
 150          * table is taken from a page allocated for the purpose.  Each
 151          * page can hold 8 pointer tables.  The page is remapped in
 152          * virtual address space to be noncacheable.
 153          */
 154         if (mask == 0) {
 155                 void *page;
 156                 ptable_desc *new;
 157
 158                 if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
 159                         return NULL;
 160
 161                 switch (type) {
 162                 case TABLE_PTE:
 163                         /*
 164                          * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
 165                          * SMP.
 166                          */
 167                         pagetable_pte_ctor(virt_to_ptdesc(page));
 168                         break;
 169                 case TABLE_PMD:
 170                         pagetable_pmd_ctor(virt_to_ptdesc(page));
 171                         break;
 172                 case TABLE_PGD:
 173                         pagetable_pgd_ctor(virt_to_ptdesc(page));
 174                         break;
 175                 }
 176
 177                 mmu_page_ctor(page);
 178
 179                 new = PD_PTABLE(page);
 180                 PD_MARKBITS(new) = ptable_mask(type) - 1;
 181                 list_add_tail(new, dp);
 182
 183                 return (pmd_t *)page;
 184         }
 185
 186         for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
 187                 ;
 188         PD_MARKBITS(dp) = mask & ~tmp;
 189         if (!PD_MARKBITS(dp)) {
 190                 /* move to end of list */
 191                 list_move_tail(dp, &ptable_list[type]);
 192         }
 193         return page_address(PD_PAGE(dp)) + off;
 194 }
 195
 196 int free_pointer_table(void *table, int type)
 197 {
 198         ptable_desc *dp;
 199         unsigned long ptable = (unsigned long)table;
 200         unsigned long page = ptable & PAGE_MASK;
 201         unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
 202
 203         dp = PD_PTABLE(page);
 204         if (PD_MARKBITS (dp) & mask)
 205                 panic ("table already free!");
 206
 207         PD_MARKBITS (dp) |= mask;
 208
 209         if (PD_MARKBITS(dp) == ptable_mask(type)) {
 210                 /* all tables in page are free, free page */
 211                 list_del(dp);
 212                 mmu_page_dtor((void *)page);
 213                 pagetable_dtor(virt_to_ptdesc((void *)page));
 214                 free_page (page);
 215                 return 1;
 216         } else if (ptable_list[type].next != dp) {
 217                 /*
 218                  * move this descriptor to the front of the list, since
 219                  * it has one or more free tables.
 220                  */
 221                 list_move(dp, &ptable_list[type]);
 222         }
 223         return 0;
 224 }
 225
 226 /* size of memory already mapped in head.S */
 227 extern __initdata unsigned long m68k_init_mapped_size;
 228
 229 extern unsigned long availmem;
 230
 231 static pte_t *last_pte_table __initdata = NULL;
 232
 233 static pte_t * __init kernel_page_table(void)
 234 {
 235         pte_t *pte_table = last_pte_table;
 236
 237         if (PAGE_ALIGNED(last_pte_table)) {
 238                 pte_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
 239                 if (!pte_table) {
 240                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 241                                         __func__, PAGE_SIZE, PAGE_SIZE);
 242                 }
 243
 244                 clear_page(pte_table);
 245                 mmu_page_ctor(pte_table);
 246
 247                 last_pte_table = pte_table;
 248         }
 249
 250         last_pte_table += PTRS_PER_PTE;
 251
 252         return pte_table;
 253 }
 254
 255 static pmd_t *last_pmd_table __initdata = NULL;
 256
 257 static pmd_t * __init kernel_ptr_table(void)
 258 {
 259         if (!last_pmd_table) {
 260                 unsigned long pmd, last;
 261                 int i;
 262
 263                 /* Find the last ptr table that was used in head.S and
 264                  * reuse the remaining space in that page for further
 265                  * ptr tables.
 266                  */
 267                 last = (unsigned long)kernel_pg_dir;
 268                 for (i = 0; i < PTRS_PER_PGD; i++) {
 269                         pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
 270
 271                         if (!pud_present(*pud))
 272                                 continue;
 273                         pmd = pgd_page_vaddr(kernel_pg_dir[i]);
 274                         if (pmd > last)
 275                                 last = pmd;
 276                 }
 277
 278                 last_pmd_table = (pmd_t *)last;
 279 #ifdef DEBUG
 280                 printk("kernel_ptr_init: %p\n", last_pmd_table);
 281 #endif
 282         }
 283
 284         last_pmd_table += PTRS_PER_PMD;
 285         if (PAGE_ALIGNED(last_pmd_table)) {
 286                 last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
 287                 if (!last_pmd_table)
 288                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 289                               __func__, PAGE_SIZE, PAGE_SIZE);
 290
 291                 clear_page(last_pmd_table);
 292                 mmu_page_ctor(last_pmd_table);
 293         }
 294
 295         return last_pmd_table;
 296 }
 297
 298 static void __init map_node(int node)
 299 {
 300         unsigned long physaddr, virtaddr, size;
 301         pgd_t *pgd_dir;
 302         p4d_t *p4d_dir;
 303         pud_t *pud_dir;
 304         pmd_t *pmd_dir;
 305         pte_t *pte_dir;
 306
 307         size = m68k_memory[node].size;
 308         physaddr = m68k_memory[node].addr;
 309         virtaddr = (unsigned long)phys_to_virt(physaddr);
 310         physaddr |= m68k_supervisor_cachemode |
 311                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
 312         if (CPU_IS_040_OR_060)
 313                 physaddr |= _PAGE_GLOBAL040;
 314
 315         while (size > 0) {
 316 #ifdef DEBUG
 317                 if (!(virtaddr & (PMD_SIZE-1)))
 318                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 319                                 virtaddr);
 320 #endif
 321                 pgd_dir = pgd_offset_k(virtaddr);
 322                 if (virtaddr && CPU_IS_020_OR_030) {
 323                         if (!(virtaddr & (PGDIR_SIZE-1)) &&
 324                             size >= PGDIR_SIZE) {
 325 #ifdef DEBUG
 326                                 printk ("[very early term]");
 327 #endif
 328                                 pgd_val(*pgd_dir) = physaddr;
 329                                 size -= PGDIR_SIZE;
 330                                 virtaddr += PGDIR_SIZE;
 331                                 physaddr += PGDIR_SIZE;
 332                                 continue;
 333                         }
 334                 }
 335                 p4d_dir = p4d_offset(pgd_dir, virtaddr);
 336                 pud_dir = pud_offset(p4d_dir, virtaddr);
 337                 if (!pud_present(*pud_dir)) {
 338                         pmd_dir = kernel_ptr_table();
 339 #ifdef DEBUG
 340                         printk ("[new pointer %p]", pmd_dir);
 341 #endif
 342                         pud_set(pud_dir, pmd_dir);
 343                 } else
 344                         pmd_dir = pmd_offset(pud_dir, virtaddr);
 345
 346                 if (CPU_IS_020_OR_030) {
 347                         if (virtaddr) {
 348 #ifdef DEBUG
 349                                 printk ("[early term]");
 350 #endif
 351                                 pmd_val(*pmd_dir) = physaddr;
 352                                 physaddr += PMD_SIZE;
 353                         } else {
 354                                 int i;
 355 #ifdef DEBUG
 356                                 printk ("[zero map]");
 357 #endif
 358                                 pte_dir = kernel_page_table();
 359                                 pmd_set(pmd_dir, pte_dir);
 360
 361                                 pte_val(*pte_dir++) = 0;
 362                                 physaddr += PAGE_SIZE;
 363                                 for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++)
 364                                         pte_val(*pte_dir++) = physaddr;
 365                         }
 366                         size -= PMD_SIZE;
 367                         virtaddr += PMD_SIZE;
 368                 } else {
 369                         if (!pmd_present(*pmd_dir)) {
 370 #ifdef DEBUG
 371                                 printk ("[new table]");
 372 #endif
 373                                 pte_dir = kernel_page_table();
 374                                 pmd_set(pmd_dir, pte_dir);
 375                         }
 376                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 377
 378                         if (virtaddr) {
 379                                 if (!pte_present(*pte_dir))
 380                                         pte_val(*pte_dir) = physaddr;
 381                         } else
 382                                 pte_val(*pte_dir) = 0;
 383                         size -= PAGE_SIZE;
 384                         virtaddr += PAGE_SIZE;
 385                         physaddr += PAGE_SIZE;
 386                 }
 387
 388         }
 389 #ifdef DEBUG
 390         printk("\n");
 391 #endif
 392 }
 393
 394 /*
 395  * Alternate definitions that are compile time constants, for
 396  * initializing protection_map.  The cachebits are fixed later.
 397  */
 398 #define PAGE_NONE_C     __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
 399 #define PAGE_SHARED_C   __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
 400 #define PAGE_COPY_C     __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
 401 #define PAGE_READONLY_C __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
 402
 403 static pgprot_t protection_map[16] __ro_after_init = {
 404         [VM_NONE]                                       = PAGE_NONE_C,
 405         [VM_READ]                                       = PAGE_READONLY_C,
 406         [VM_WRITE]                                      = PAGE_COPY_C,
 407         [VM_WRITE | VM_READ]                            = PAGE_COPY_C,
 408         [VM_EXEC]                                       = PAGE_READONLY_C,
 409         [VM_EXEC | VM_READ]                             = PAGE_READONLY_C,
 410         [VM_EXEC | VM_WRITE]                            = PAGE_COPY_C,
 411         [VM_EXEC | VM_WRITE | VM_READ]                  = PAGE_COPY_C,
 412         [VM_SHARED]                                     = PAGE_NONE_C,
 413         [VM_SHARED | VM_READ]                           = PAGE_READONLY_C,
 414         [VM_SHARED | VM_WRITE]                          = PAGE_SHARED_C,
 415         [VM_SHARED | VM_WRITE | VM_READ]                = PAGE_SHARED_C,
 416         [VM_SHARED | VM_EXEC]                           = PAGE_READONLY_C,
 417         [VM_SHARED | VM_EXEC | VM_READ]                 = PAGE_READONLY_C,
 418         [VM_SHARED | VM_EXEC | VM_WRITE]                = PAGE_SHARED_C,
 419         [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = PAGE_SHARED_C
 420 };
 421 DECLARE_VM_GET_PAGE_PROT
 422
 423 /*
 424  * paging_init() continues the virtual memory environment setup which
 425  * was begun by the code in arch/head.S.
 426  */
 427 void __init paging_init(void)
 428 {
 429         unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
 430         unsigned long min_addr, max_addr;
 431         unsigned long addr;
 432         int i;
 433
 434 #ifdef DEBUG
 435         printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
 436 #endif
 437
 438         /* Fix the cache mode in the page descriptors for the 680[46]0.  */
 439         if (CPU_IS_040_OR_060) {
 440                 int i;
 441 #ifndef mm_cachebits
 442                 mm_cachebits = _PAGE_CACHE040;
 443 #endif
 444                 for (i = 0; i < 16; i++)
 445                         pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
 446         }
 447
 448         min_addr = m68k_memory[0].addr;
 449         max_addr = min_addr + m68k_memory[0].size - 1;
 450         memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
 451                           MEMBLOCK_NONE);
 452         for (i = 1; i < m68k_num_memory;) {
 453                 if (m68k_memory[i].addr < min_addr) {
 454                         printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
 455                                 m68k_memory[i].addr, m68k_memory[i].size);
 456                         printk("Fix your bootloader or use a memfile to make use of this area!\n");
 457                         m68k_num_memory--;
 458                         memmove(m68k_memory + i, m68k_memory + i + 1,
 459                                 (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
 460                         continue;
 461                 }
 462                 memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i,
 463                                   MEMBLOCK_NONE);
 464                 addr = m68k_memory[i].addr + m68k_memory[i].size - 1;
 465                 if (addr > max_addr)
 466                         max_addr = addr;
 467                 i++;
 468         }
 469         m68k_memoffset = min_addr - PAGE_OFFSET;
 470         m68k_virt_to_node_shift = fls(max_addr - min_addr) - 6;
 471
 472         module_fixup(NULL, __start_fixup, __stop_fixup);
 473         flush_icache();
 474
 475         high_memory = phys_to_virt(max_addr) + 1;
 476
 477         min_low_pfn = availmem >> PAGE_SHIFT;
 478         max_pfn = max_low_pfn = (max_addr >> PAGE_SHIFT) + 1;
 479
 480         /* Reserve kernel text/data/bss and the memory allocated in head.S */
 481         memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
 482
 483         /*
 484          * Map the physical memory available into the kernel virtual
 485          * address space. Make sure memblock will not try to allocate
 486          * pages beyond the memory we already mapped in head.S
 487          */
 488         memblock_set_bottom_up(true);
 489
 490         for (i = 0; i < m68k_num_memory; i++) {
 491                 m68k_setup_node(i);
 492                 map_node(i);
 493         }
 494
 495         flush_tlb_all();
 496
 497         early_memtest(min_addr, max_addr);
 498
 499         /*
 500          * initialize the bad page table and bad page to point
 501          * to a couple of allocated pages
 502          */
 503         empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
 504
 505         /*
 506          * Set up SFC/DFC registers
 507          */
 508         set_fc(USER_DATA);
 509
 510 #ifdef DEBUG
 511         printk ("before free_area_init\n");
 512 #endif
 513         for (i = 0; i < m68k_num_memory; i++)
 514                 if (node_present_pages(i))
 515                         node_set_state(i, N_NORMAL_MEMORY);
 516
 517         max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM();
 518         free_area_init(max_zone_pfn);
 519 }