arch/m68k/mm/motorola.c

   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