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 49 /* 50 * Motorola 680x0 user's manual recommends using uncached memory for address 51 * translation tables. 52 * 53 * Seeing how the MMU can be external on (some of) these chips, that seems like 54 * a very important recommendation to follow. Provide some helpers to combat 55 * 'variation' amongst the users of this. 56 */ 57 58 void mmu_page_ctor(void *page) 59 { 60 __flush_page_to_ram(page); 61 flush_tlb_kernel_page(page); 62 nocache_page(page); 63 } 64 65 void mmu_page_dtor(void *page) 66 { 67 cache_page(page); 68 } 69 70 /* size of memory already mapped in head.S */ 71 extern __initdata unsigned long m68k_init_mapped_size; 72 73 extern unsigned long availmem; 74 75 static pte_t * __init kernel_page_table(void) 76 { 77 pte_t *ptablep; 78 79 ptablep = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 80 if (!ptablep) 81 panic("%s: Failed to allocate %lu bytes align=%lx\n", 82 __func__, PAGE_SIZE, PAGE_SIZE); 83 84 clear_page(ptablep); 85 mmu_page_ctor(ptablep); 86 87 return ptablep; 88 } 89 90 static pmd_t *last_pgtable __initdata = NULL; 91 pmd_t *zero_pgtable __initdata = NULL; 92 93 static pmd_t * __init kernel_ptr_table(void) 94 { 95 if (!last_pgtable) { 96 unsigned long pmd, last; 97 int i; 98 99 /* Find the last ptr table that was used in head.S and 100 * reuse the remaining space in that page for further 101 * ptr tables. 102 */ 103 last = (unsigned long)kernel_pg_dir; 104 for (i = 0; i < PTRS_PER_PGD; i++) { 105 pud_t *pud = (pud_t *)(&kernel_pg_dir[i]); 106 107 if (!pud_present(*pud)) 108 continue; 109 pmd = pgd_page_vaddr(kernel_pg_dir[i]); 110 if (pmd > last) 111 last = pmd; 112 } 113 114 last_pgtable = (pmd_t *)last; 115 #ifdef DEBUG 116 printk("kernel_ptr_init: %p\n", last_pgtable); 117 #endif 118 } 119 120 last_pgtable += PTRS_PER_PMD; 121 if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) { 122 last_pgtable = (pmd_t *)memblock_alloc_low(PAGE_SIZE, 123 PAGE_SIZE); 124 if (!last_pgtable) 125 panic("%s: Failed to allocate %lu bytes align=%lx\n", 126 __func__, PAGE_SIZE, PAGE_SIZE); 127 128 clear_page(last_pgtable); 129 mmu_page_ctor(last_pgtable); 130 } 131 132 return last_pgtable; 133 } 134 135 static void __init map_node(int node) 136 { 137 #define PTRTREESIZE (256*1024) 138 #define ROOTTREESIZE (32*1024*1024) 139 unsigned long physaddr, virtaddr, size; 140 pgd_t *pgd_dir; 141 p4d_t *p4d_dir; 142 pud_t *pud_dir; 143 pmd_t *pmd_dir; 144 pte_t *pte_dir; 145 146 size = m68k_memory[node].size; 147 physaddr = m68k_memory[node].addr; 148 virtaddr = (unsigned long)phys_to_virt(physaddr); 149 physaddr |= m68k_supervisor_cachemode | 150 _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY; 151 if (CPU_IS_040_OR_060) 152 physaddr |= _PAGE_GLOBAL040; 153 154 while (size > 0) { 155 #ifdef DEBUG 156 if (!(virtaddr & (PTRTREESIZE-1))) 157 printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK, 158 virtaddr); 159 #endif 160 pgd_dir = pgd_offset_k(virtaddr); 161 if (virtaddr && CPU_IS_020_OR_030) { 162 if (!(virtaddr & (ROOTTREESIZE-1)) && 163 size >= ROOTTREESIZE) { 164 #ifdef DEBUG 165 printk ("[very early term]"); 166 #endif 167 pgd_val(*pgd_dir) = physaddr; 168 size -= ROOTTREESIZE; 169 virtaddr += ROOTTREESIZE; 170 physaddr += ROOTTREESIZE; 171 continue; 172 } 173 } 174 p4d_dir = p4d_offset(pgd_dir, virtaddr); 175 pud_dir = pud_offset(p4d_dir, virtaddr); 176 if (!pud_present(*pud_dir)) { 177 pmd_dir = kernel_ptr_table(); 178 #ifdef DEBUG 179 printk ("[new pointer %p]", pmd_dir); 180 #endif 181 pud_set(pud_dir, pmd_dir); 182 } else 183 pmd_dir = pmd_offset(pud_dir, virtaddr); 184 185 if (CPU_IS_020_OR_030) { 186 if (virtaddr) { 187 #ifdef DEBUG 188 printk ("[early term]"); 189 #endif 190 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr; 191 physaddr += PTRTREESIZE; 192 } else { 193 int i; 194 #ifdef DEBUG 195 printk ("[zero map]"); 196 #endif 197 zero_pgtable = kernel_ptr_table(); 198 pte_dir = (pte_t *)zero_pgtable; 199 pmd_dir->pmd[0] = virt_to_phys(pte_dir) | 200 _PAGE_TABLE | _PAGE_ACCESSED; 201 pte_val(*pte_dir++) = 0; 202 physaddr += PAGE_SIZE; 203 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++) 204 pte_val(*pte_dir++) = physaddr; 205 } 206 size -= PTRTREESIZE; 207 virtaddr += PTRTREESIZE; 208 } else { 209 if (!pmd_present(*pmd_dir)) { 210 #ifdef DEBUG 211 printk ("[new table]"); 212 #endif 213 pte_dir = kernel_page_table(); 214 pmd_set(pmd_dir, pte_dir); 215 } 216 pte_dir = pte_offset_kernel(pmd_dir, virtaddr); 217 218 if (virtaddr) { 219 if (!pte_present(*pte_dir)) 220 pte_val(*pte_dir) = physaddr; 221 } else 222 pte_val(*pte_dir) = 0; 223 size -= PAGE_SIZE; 224 virtaddr += PAGE_SIZE; 225 physaddr += PAGE_SIZE; 226 } 227 228 } 229 #ifdef DEBUG 230 printk("\n"); 231 #endif 232 } 233 234 /* 235 * paging_init() continues the virtual memory environment setup which 236 * was begun by the code in arch/head.S. 237 */ 238 void __init paging_init(void) 239 { 240 unsigned long zones_size[MAX_NR_ZONES] = { 0, }; 241 unsigned long min_addr, max_addr; 242 unsigned long addr; 243 int i; 244 245 #ifdef DEBUG 246 printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem); 247 #endif 248 249 /* Fix the cache mode in the page descriptors for the 680[46]0. */ 250 if (CPU_IS_040_OR_060) { 251 int i; 252 #ifndef mm_cachebits 253 mm_cachebits = _PAGE_CACHE040; 254 #endif 255 for (i = 0; i < 16; i++) 256 pgprot_val(protection_map[i]) |= _PAGE_CACHE040; 257 } 258 259 min_addr = m68k_memory[0].addr; 260 max_addr = min_addr + m68k_memory[0].size; 261 memblock_add(m68k_memory[0].addr, m68k_memory[0].size); 262 for (i = 1; i < m68k_num_memory;) { 263 if (m68k_memory[i].addr < min_addr) { 264 printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n", 265 m68k_memory[i].addr, m68k_memory[i].size); 266 printk("Fix your bootloader or use a memfile to make use of this area!\n"); 267 m68k_num_memory--; 268 memmove(m68k_memory + i, m68k_memory + i + 1, 269 (m68k_num_memory - i) * sizeof(struct m68k_mem_info)); 270 continue; 271 } 272 memblock_add(m68k_memory[i].addr, m68k_memory[i].size); 273 addr = m68k_memory[i].addr + m68k_memory[i].size; 274 if (addr > max_addr) 275 max_addr = addr; 276 i++; 277 } 278 m68k_memoffset = min_addr - PAGE_OFFSET; 279 m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6; 280 281 module_fixup(NULL, __start_fixup, __stop_fixup); 282 flush_icache(); 283 284 high_memory = phys_to_virt(max_addr); 285 286 min_low_pfn = availmem >> PAGE_SHIFT; 287 max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT; 288 289 /* Reserve kernel text/data/bss and the memory allocated in head.S */ 290 memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr); 291 292 /* 293 * Map the physical memory available into the kernel virtual 294 * address space. Make sure memblock will not try to allocate 295 * pages beyond the memory we already mapped in head.S 296 */ 297 memblock_set_bottom_up(true); 298 299 for (i = 0; i < m68k_num_memory; i++) { 300 m68k_setup_node(i); 301 map_node(i); 302 } 303 304 flush_tlb_all(); 305 306 /* 307 * initialize the bad page table and bad page to point 308 * to a couple of allocated pages 309 */ 310 empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 311 if (!empty_zero_page) 312 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 313 __func__, PAGE_SIZE, PAGE_SIZE); 314 315 /* 316 * Set up SFC/DFC registers 317 */ 318 set_fs(KERNEL_DS); 319 320 #ifdef DEBUG 321 printk ("before free_area_init\n"); 322 #endif 323 for (i = 0; i < m68k_num_memory; i++) { 324 zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT; 325 free_area_init_node(i, zones_size, 326 m68k_memory[i].addr >> PAGE_SHIFT, NULL); 327 if (node_present_pages(i)) 328 node_set_state(i, N_NORMAL_MEMORY); 329 } 330 } 331