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 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 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 } 108 109 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 */ 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 for (i = 1; i < m68k_num_memory;) { 232 if (m68k_memory[i].addr < min_addr) { 233 printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n", 234 m68k_memory[i].addr, m68k_memory[i].size); 235 printk("Fix your bootloader or use a memfile to make use of this area!\n"); 236 m68k_num_memory--; 237 memmove(m68k_memory + i, m68k_memory + i + 1, 238 (m68k_num_memory - i) * sizeof(struct m68k_mem_info)); 239 continue; 240 } 241 addr = m68k_memory[i].addr + m68k_memory[i].size; 242 if (addr > max_addr) 243 max_addr = addr; 244 i++; 245 } 246 m68k_memoffset = min_addr - PAGE_OFFSET; 247 m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6; 248 249 module_fixup(NULL, __start_fixup, __stop_fixup); 250 flush_icache(); 251 252 high_memory = phys_to_virt(max_addr); 253 254 min_low_pfn = availmem >> PAGE_SHIFT; 255 max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT; 256 257 /* Reserve kernel text/data/bss and the memory allocated in head.S */ 258 memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr); 259 260 /* 261 * Map the physical memory available into the kernel virtual 262 * address space. Make sure memblock will not try to allocate 263 * pages beyond the memory we already mapped in head.S 264 */ 265 memblock_set_bottom_up(true); 266 267 for (i = 0; i < m68k_num_memory; i++) { 268 m68k_setup_node(i); 269 map_node(i); 270 } 271 272 flush_tlb_all(); 273 274 /* 275 * initialize the bad page table and bad page to point 276 * to a couple of allocated pages 277 */ 278 empty_zero_page = alloc_bootmem_pages(PAGE_SIZE); 279 280 /* 281 * Set up SFC/DFC registers 282 */ 283 set_fs(KERNEL_DS); 284 285 #ifdef DEBUG 286 printk ("before free_area_init\n"); 287 #endif 288 for (i = 0; i < m68k_num_memory; i++) { 289 zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT; 290 free_area_init_node(i, zones_size, 291 m68k_memory[i].addr >> PAGE_SHIFT, NULL); 292 if (node_present_pages(i)) 293 node_set_state(i, N_NORMAL_MEMORY); 294 } 295 } 296 297