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