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 }
514
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