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