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 } 520