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/bootmem.h>
22 #include <linux/memblock.h>
23 #include <linux/gfp.h>
24
25 #include <asm/setup.h>
26 #include <linux/uaccess.h>
27 #include <asm/page.h>
28 #include <asm/pgalloc.h>
29 #include <asm/machdep.h>
30 #include <asm/io.h>
31 #include <asm/dma.h>
32 #ifdef CONFIG_ATARI
33 #include <asm/atari_stram.h>
34 #endif
35 #include <asm/sections.h>
36
37 #undef DEBUG
38
39 #ifndef mm_cachebits
40 /*
41 * Bits to add to page descriptors for "normal" caching mode.
42 * For 68020/030 this is 0.
43 * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
44 */
45 unsigned long mm_cachebits;
46 EXPORT_SYMBOL(mm_cachebits);
47 #endif
48
49 /* size of memory already mapped in head.S */
50 extern __initdata unsigned long m68k_init_mapped_size;
51
52 extern unsigned long availmem;
53
kernel_page_table(void)54 static pte_t * __init kernel_page_table(void)
55 {
56 pte_t *ptablep;
57
58 ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
59
60 clear_page(ptablep);
61 __flush_page_to_ram(ptablep);
62 flush_tlb_kernel_page(ptablep);
63 nocache_page(ptablep);
64
65 return ptablep;
66 }
67
68 static pmd_t *last_pgtable __initdata = NULL;
69 pmd_t *zero_pgtable __initdata = NULL;
70
kernel_ptr_table(void)71 static pmd_t * __init kernel_ptr_table(void)
72 {
73 if (!last_pgtable) {
74 unsigned long pmd, last;
75 int i;
76
77 /* Find the last ptr table that was used in head.S and
78 * reuse the remaining space in that page for further
79 * ptr tables.
80 */
81 last = (unsigned long)kernel_pg_dir;
82 for (i = 0; i < PTRS_PER_PGD; i++) {
83 if (!pgd_present(kernel_pg_dir[i]))
84 continue;
85 pmd = __pgd_page(kernel_pg_dir[i]);
86 if (pmd > last)
87 last = pmd;
88 }
89
90 last_pgtable = (pmd_t *)last;
91 #ifdef DEBUG
92 printk("kernel_ptr_init: %p\n", last_pgtable);
93 #endif
94 }
95
96 last_pgtable += PTRS_PER_PMD;
97 if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
98 last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
99
100 clear_page(last_pgtable);
101 __flush_page_to_ram(last_pgtable);
102 flush_tlb_kernel_page(last_pgtable);
103 nocache_page(last_pgtable);
104 }
105
106 return last_pgtable;
107 }
108
map_node(int node)109 static void __init map_node(int node)
110 {
111 #define PTRTREESIZE (256*1024)
112 #define ROOTTREESIZE (32*1024*1024)
113 unsigned long physaddr, virtaddr, size;
114 pgd_t *pgd_dir;
115 pmd_t *pmd_dir;
116 pte_t *pte_dir;
117
118 size = m68k_memory[node].size;
119 physaddr = m68k_memory[node].addr;
120 virtaddr = (unsigned long)phys_to_virt(physaddr);
121 physaddr |= m68k_supervisor_cachemode |
122 _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
123 if (CPU_IS_040_OR_060)
124 physaddr |= _PAGE_GLOBAL040;
125
126 while (size > 0) {
127 #ifdef DEBUG
128 if (!(virtaddr & (PTRTREESIZE-1)))
129 printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
130 virtaddr);
131 #endif
132 pgd_dir = pgd_offset_k(virtaddr);
133 if (virtaddr && CPU_IS_020_OR_030) {
134 if (!(virtaddr & (ROOTTREESIZE-1)) &&
135 size >= ROOTTREESIZE) {
136 #ifdef DEBUG
137 printk ("[very early term]");
138 #endif
139 pgd_val(*pgd_dir) = physaddr;
140 size -= ROOTTREESIZE;
141 virtaddr += ROOTTREESIZE;
142 physaddr += ROOTTREESIZE;
143 continue;
144 }
145 }
146 if (!pgd_present(*pgd_dir)) {
147 pmd_dir = kernel_ptr_table();
148 #ifdef DEBUG
149 printk ("[new pointer %p]", pmd_dir);
150 #endif
151 pgd_set(pgd_dir, pmd_dir);
152 } else
153 pmd_dir = pmd_offset(pgd_dir, virtaddr);
154
155 if (CPU_IS_020_OR_030) {
156 if (virtaddr) {
157 #ifdef DEBUG
158 printk ("[early term]");
159 #endif
160 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
161 physaddr += PTRTREESIZE;
162 } else {
163 int i;
164 #ifdef DEBUG
165 printk ("[zero map]");
166 #endif
167 zero_pgtable = kernel_ptr_table();
168 pte_dir = (pte_t *)zero_pgtable;
169 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
170 _PAGE_TABLE | _PAGE_ACCESSED;
171 pte_val(*pte_dir++) = 0;
172 physaddr += PAGE_SIZE;
173 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
174 pte_val(*pte_dir++) = physaddr;
175 }
176 size -= PTRTREESIZE;
177 virtaddr += PTRTREESIZE;
178 } else {
179 if (!pmd_present(*pmd_dir)) {
180 #ifdef DEBUG
181 printk ("[new table]");
182 #endif
183 pte_dir = kernel_page_table();
184 pmd_set(pmd_dir, pte_dir);
185 }
186 pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
187
188 if (virtaddr) {
189 if (!pte_present(*pte_dir))
190 pte_val(*pte_dir) = physaddr;
191 } else
192 pte_val(*pte_dir) = 0;
193 size -= PAGE_SIZE;
194 virtaddr += PAGE_SIZE;
195 physaddr += PAGE_SIZE;
196 }
197
198 }
199 #ifdef DEBUG
200 printk("\n");
201 #endif
202 }
203
204 /*
205 * paging_init() continues the virtual memory environment setup which
206 * was begun by the code in arch/head.S.
207 */
paging_init(void)208 void __init paging_init(void)
209 {
210 unsigned long zones_size[MAX_NR_ZONES] = { 0, };
211 unsigned long min_addr, max_addr;
212 unsigned long addr;
213 int i;
214
215 #ifdef DEBUG
216 printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
217 #endif
218
219 /* Fix the cache mode in the page descriptors for the 680[46]0. */
220 if (CPU_IS_040_OR_060) {
221 int i;
222 #ifndef mm_cachebits
223 mm_cachebits = _PAGE_CACHE040;
224 #endif
225 for (i = 0; i < 16; i++)
226 pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
227 }
228
229 min_addr = m68k_memory[0].addr;
230 max_addr = min_addr + m68k_memory[0].size;
231 memblock_add(m68k_memory[0].addr, m68k_memory[0].size);
232 for (i = 1; i < m68k_num_memory;) {
233 if (m68k_memory[i].addr < min_addr) {
234 printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
235 m68k_memory[i].addr, m68k_memory[i].size);
236 printk("Fix your bootloader or use a memfile to make use of this area!\n");
237 m68k_num_memory--;
238 memmove(m68k_memory + i, m68k_memory + i + 1,
239 (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
240 continue;
241 }
242 memblock_add(m68k_memory[i].addr, m68k_memory[i].size);
243 addr = m68k_memory[i].addr + m68k_memory[i].size;
244 if (addr > max_addr)
245 max_addr = addr;
246 i++;
247 }
248 m68k_memoffset = min_addr - PAGE_OFFSET;
249 m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
250
251 module_fixup(NULL, __start_fixup, __stop_fixup);
252 flush_icache();
253
254 high_memory = phys_to_virt(max_addr);
255
256 min_low_pfn = availmem >> PAGE_SHIFT;
257 max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT;
258
259 /* Reserve kernel text/data/bss and the memory allocated in head.S */
260 memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
261
262 /*
263 * Map the physical memory available into the kernel virtual
264 * address space. Make sure memblock will not try to allocate
265 * pages beyond the memory we already mapped in head.S
266 */
267 memblock_set_bottom_up(true);
268
269 for (i = 0; i < m68k_num_memory; i++) {
270 m68k_setup_node(i);
271 map_node(i);
272 }
273
274 flush_tlb_all();
275
276 /*
277 * initialize the bad page table and bad page to point
278 * to a couple of allocated pages
279 */
280 empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
281
282 /*
283 * Set up SFC/DFC registers
284 */
285 set_fs(KERNEL_DS);
286
287 #ifdef DEBUG
288 printk ("before free_area_init\n");
289 #endif
290 for (i = 0; i < m68k_num_memory; i++) {
291 zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
292 free_area_init_node(i, zones_size,
293 m68k_memory[i].addr >> PAGE_SHIFT, NULL);
294 if (node_present_pages(i))
295 node_set_state(i, N_NORMAL_MEMORY);
296 }
297 }
298
299