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_PTDESC(ptable) (list_entry(ptable, struct ptdesc, pt_list)) 109 #define PD_MARKBITS(dp) (*(unsigned int *)&PD_PTDESC(dp)->pt_index) 110 111 static const int ptable_shift[3] = { 112 7+2, /* PGD */ 113 7+2, /* PMD */ 114 6+2, /* PTE */ 115 }; 116 117 #define ptable_size(type) (1U << ptable_shift[type]) 118 #define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1) 119 120 void __init init_pointer_table(void *table, int type) 121 { 122 ptable_desc *dp; 123 unsigned long ptable = (unsigned long)table; 124 unsigned long page = ptable & PAGE_MASK; 125 unsigned int mask = 1U << ((ptable - page)/ptable_size(type)); 126 127 dp = PD_PTABLE(page); 128 if (!(PD_MARKBITS(dp) & mask)) { 129 PD_MARKBITS(dp) = ptable_mask(type); 130 list_add(dp, &ptable_list[type]); 131 } 132 133 PD_MARKBITS(dp) &= ~mask; 134 pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp)); 135 136 /* unreserve the page so it's possible to free that page */ 137 __ClearPageReserved(PD_PAGE(dp)); 138 init_page_count(PD_PAGE(dp)); 139 140 return; 141 } 142 143 void *get_pointer_table(struct mm_struct *mm, int type) 144 { 145 ptable_desc *dp = ptable_list[type].next; 146 unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp); 147 unsigned int tmp, off; 148 149 /* 150 * For a pointer table for a user process address space, a 151 * table is taken from a page allocated for the purpose. Each 152 * page can hold 8 pointer tables. The page is remapped in 153 * virtual address space to be noncacheable. 154 */ 155 if (mask == 0) { 156 void *page; 157 ptable_desc *new; 158 159 if (!(page = (void *)get_zeroed_page(GFP_KERNEL))) 160 return NULL; 161 162 switch (type) { 163 case TABLE_PTE: 164 /* 165 * m68k doesn't have SPLIT_PTE_PTLOCKS for not having 166 * SMP. 167 */ 168 pagetable_pte_ctor(mm, virt_to_ptdesc(page)); 169 break; 170 case TABLE_PMD: 171 pagetable_pmd_ctor(mm, virt_to_ptdesc(page)); 172 break; 173 case TABLE_PGD: 174 pagetable_pgd_ctor(virt_to_ptdesc(page)); 175 break; 176 } 177 178 mmu_page_ctor(page); 179 180 new = PD_PTABLE(page); 181 PD_MARKBITS(new) = ptable_mask(type) - 1; 182 list_add_tail(new, dp); 183 184 return (pmd_t *)page; 185 } 186 187 for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type)) 188 ; 189 PD_MARKBITS(dp) = mask & ~tmp; 190 if (!PD_MARKBITS(dp)) { 191 /* move to end of list */ 192 list_move_tail(dp, &ptable_list[type]); 193 } 194 return page_address(PD_PAGE(dp)) + off; 195 } 196 197 int free_pointer_table(void *table, int type) 198 { 199 ptable_desc *dp; 200 unsigned long ptable = (unsigned long)table; 201 unsigned long page = ptable & PAGE_MASK; 202 unsigned int mask = 1U << ((ptable - page)/ptable_size(type)); 203 204 dp = PD_PTABLE(page); 205 if (PD_MARKBITS (dp) & mask) 206 panic ("table already free!"); 207 208 PD_MARKBITS (dp) |= mask; 209 210 if (PD_MARKBITS(dp) == ptable_mask(type)) { 211 /* all tables in page are free, free page */ 212 list_del(dp); 213 mmu_page_dtor((void *)page); 214 pagetable_dtor(virt_to_ptdesc((void *)page)); 215 free_page (page); 216 return 1; 217 } else if (ptable_list[type].next != dp) { 218 /* 219 * move this descriptor to the front of the list, since 220 * it has one or more free tables. 221 */ 222 list_move(dp, &ptable_list[type]); 223 } 224 return 0; 225 } 226 227 /* size of memory already mapped in head.S */ 228 extern __initdata unsigned long m68k_init_mapped_size; 229 230 extern unsigned long availmem; 231 232 static pte_t *last_pte_table __initdata = NULL; 233 234 static pte_t * __init kernel_page_table(void) 235 { 236 pte_t *pte_table = last_pte_table; 237 238 if (PAGE_ALIGNED(last_pte_table)) { 239 pte_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 240 if (!pte_table) { 241 panic("%s: Failed to allocate %lu bytes align=%lx\n", 242 __func__, PAGE_SIZE, PAGE_SIZE); 243 } 244 245 clear_page(pte_table); 246 mmu_page_ctor(pte_table); 247 248 last_pte_table = pte_table; 249 } 250 251 last_pte_table += PTRS_PER_PTE; 252 253 return pte_table; 254 } 255 256 static pmd_t *last_pmd_table __initdata = NULL; 257 258 static pmd_t * __init kernel_ptr_table(void) 259 { 260 if (!last_pmd_table) { 261 unsigned long pmd, last; 262 int i; 263 264 /* Find the last ptr table that was used in head.S and 265 * reuse the remaining space in that page for further 266 * ptr tables. 267 */ 268 last = (unsigned long)kernel_pg_dir; 269 for (i = 0; i < PTRS_PER_PGD; i++) { 270 pud_t *pud = (pud_t *)(&kernel_pg_dir[i]); 271 272 if (!pud_present(*pud)) 273 continue; 274 pmd = pgd_page_vaddr(kernel_pg_dir[i]); 275 if (pmd > last) 276 last = pmd; 277 } 278 279 last_pmd_table = (pmd_t *)last; 280 #ifdef DEBUG 281 printk("kernel_ptr_init: %p\n", last_pmd_table); 282 #endif 283 } 284 285 last_pmd_table += PTRS_PER_PMD; 286 if (PAGE_ALIGNED(last_pmd_table)) { 287 last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 288 if (!last_pmd_table) 289 panic("%s: Failed to allocate %lu bytes align=%lx\n", 290 __func__, PAGE_SIZE, PAGE_SIZE); 291 292 clear_page(last_pmd_table); 293 mmu_page_ctor(last_pmd_table); 294 } 295 296 return last_pmd_table; 297 } 298 299 static void __init map_node(int node) 300 { 301 unsigned long physaddr, virtaddr, size; 302 pgd_t *pgd_dir; 303 p4d_t *p4d_dir; 304 pud_t *pud_dir; 305 pmd_t *pmd_dir; 306 pte_t *pte_dir; 307 308 size = m68k_memory[node].size; 309 physaddr = m68k_memory[node].addr; 310 virtaddr = (unsigned long)phys_to_virt(physaddr); 311 physaddr |= m68k_supervisor_cachemode | 312 _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY; 313 if (CPU_IS_040_OR_060) 314 physaddr |= _PAGE_GLOBAL040; 315 316 while (size > 0) { 317 #ifdef DEBUG 318 if (!(virtaddr & (PMD_SIZE-1))) 319 printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK, 320 virtaddr); 321 #endif 322 pgd_dir = pgd_offset_k(virtaddr); 323 if (virtaddr && CPU_IS_020_OR_030) { 324 if (!(virtaddr & (PGDIR_SIZE-1)) && 325 size >= PGDIR_SIZE) { 326 #ifdef DEBUG 327 printk ("[very early term]"); 328 #endif 329 pgd_val(*pgd_dir) = physaddr; 330 size -= PGDIR_SIZE; 331 virtaddr += PGDIR_SIZE; 332 physaddr += PGDIR_SIZE; 333 continue; 334 } 335 } 336 p4d_dir = p4d_offset(pgd_dir, virtaddr); 337 pud_dir = pud_offset(p4d_dir, virtaddr); 338 if (!pud_present(*pud_dir)) { 339 pmd_dir = kernel_ptr_table(); 340 #ifdef DEBUG 341 printk ("[new pointer %p]", pmd_dir); 342 #endif 343 pud_set(pud_dir, pmd_dir); 344 } else 345 pmd_dir = pmd_offset(pud_dir, virtaddr); 346 347 if (CPU_IS_020_OR_030) { 348 if (virtaddr) { 349 #ifdef DEBUG 350 printk ("[early term]"); 351 #endif 352 pmd_val(*pmd_dir) = physaddr; 353 physaddr += PMD_SIZE; 354 } else { 355 int i; 356 #ifdef DEBUG 357 printk ("[zero map]"); 358 #endif 359 pte_dir = kernel_page_table(); 360 pmd_set(pmd_dir, pte_dir); 361 362 pte_val(*pte_dir++) = 0; 363 physaddr += PAGE_SIZE; 364 for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++) 365 pte_val(*pte_dir++) = physaddr; 366 } 367 size -= PMD_SIZE; 368 virtaddr += PMD_SIZE; 369 } else { 370 if (!pmd_present(*pmd_dir)) { 371 #ifdef DEBUG 372 printk ("[new table]"); 373 #endif 374 pte_dir = kernel_page_table(); 375 pmd_set(pmd_dir, pte_dir); 376 } 377 pte_dir = pte_offset_kernel(pmd_dir, virtaddr); 378 379 if (virtaddr) { 380 if (!pte_present(*pte_dir)) 381 pte_val(*pte_dir) = physaddr; 382 } else 383 pte_val(*pte_dir) = 0; 384 size -= PAGE_SIZE; 385 virtaddr += PAGE_SIZE; 386 physaddr += PAGE_SIZE; 387 } 388 389 } 390 #ifdef DEBUG 391 printk("\n"); 392 #endif 393 } 394 395 /* 396 * Alternate definitions that are compile time constants, for 397 * initializing protection_map. The cachebits are fixed later. 398 */ 399 #define PAGE_NONE_C __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED) 400 #define PAGE_SHARED_C __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED) 401 #define PAGE_COPY_C __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED) 402 #define PAGE_READONLY_C __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED) 403 404 static pgprot_t protection_map[16] __ro_after_init = { 405 [VM_NONE] = PAGE_NONE_C, 406 [VM_READ] = PAGE_READONLY_C, 407 [VM_WRITE] = PAGE_COPY_C, 408 [VM_WRITE | VM_READ] = PAGE_COPY_C, 409 [VM_EXEC] = PAGE_READONLY_C, 410 [VM_EXEC | VM_READ] = PAGE_READONLY_C, 411 [VM_EXEC | VM_WRITE] = PAGE_COPY_C, 412 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_C, 413 [VM_SHARED] = PAGE_NONE_C, 414 [VM_SHARED | VM_READ] = PAGE_READONLY_C, 415 [VM_SHARED | VM_WRITE] = PAGE_SHARED_C, 416 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED_C, 417 [VM_SHARED | VM_EXEC] = PAGE_READONLY_C, 418 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY_C, 419 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED_C, 420 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_C 421 }; 422 DECLARE_VM_GET_PAGE_PROT 423 424 /* 425 * paging_init() continues the virtual memory environment setup which 426 * was begun by the code in arch/head.S. 427 */ 428 void __init paging_init(void) 429 { 430 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, }; 431 unsigned long min_addr, max_addr; 432 unsigned long addr; 433 int i; 434 435 #ifdef DEBUG 436 printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem); 437 #endif 438 439 /* Fix the cache mode in the page descriptors for the 680[46]0. */ 440 if (CPU_IS_040_OR_060) { 441 int i; 442 #ifndef mm_cachebits 443 mm_cachebits = _PAGE_CACHE040; 444 #endif 445 for (i = 0; i < 16; i++) 446 pgprot_val(protection_map[i]) |= _PAGE_CACHE040; 447 } 448 449 min_addr = m68k_memory[0].addr; 450 max_addr = min_addr + m68k_memory[0].size - 1; 451 memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0, 452 MEMBLOCK_NONE); 453 for (i = 1; i < m68k_num_memory;) { 454 if (m68k_memory[i].addr < min_addr) { 455 printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n", 456 m68k_memory[i].addr, m68k_memory[i].size); 457 printk("Fix your bootloader or use a memfile to make use of this area!\n"); 458 m68k_num_memory--; 459 memmove(m68k_memory + i, m68k_memory + i + 1, 460 (m68k_num_memory - i) * sizeof(struct m68k_mem_info)); 461 continue; 462 } 463 memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i, 464 MEMBLOCK_NONE); 465 addr = m68k_memory[i].addr + m68k_memory[i].size - 1; 466 if (addr > max_addr) 467 max_addr = addr; 468 i++; 469 } 470 m68k_memoffset = min_addr - PAGE_OFFSET; 471 m68k_virt_to_node_shift = fls(max_addr - min_addr) - 6; 472 473 module_fixup(NULL, __start_fixup, __stop_fixup); 474 flush_icache(); 475 476 high_memory = phys_to_virt(max_addr) + 1; 477 478 min_low_pfn = availmem >> PAGE_SHIFT; 479 max_pfn = max_low_pfn = (max_addr >> PAGE_SHIFT) + 1; 480 481 /* Reserve kernel text/data/bss and the memory allocated in head.S */ 482 memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr); 483 484 /* 485 * Map the physical memory available into the kernel virtual 486 * address space. Make sure memblock will not try to allocate 487 * pages beyond the memory we already mapped in head.S 488 */ 489 memblock_set_bottom_up(true); 490 491 for (i = 0; i < m68k_num_memory; i++) { 492 m68k_setup_node(i); 493 map_node(i); 494 } 495 496 flush_tlb_all(); 497 498 early_memtest(min_addr, max_addr); 499 500 /* 501 * initialize the bad page table and bad page to point 502 * to a couple of allocated pages 503 */ 504 empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE); 505 506 /* 507 * Set up SFC/DFC registers 508 */ 509 set_fc(USER_DATA); 510 511 #ifdef DEBUG 512 printk ("before free_area_init\n"); 513 #endif 514 for (i = 0; i < m68k_num_memory; i++) 515 if (node_present_pages(i)) 516 node_set_state(i, N_NORMAL_MEMORY); 517 518 max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM(); 519 free_area_init(max_zone_pfn); 520 } 521