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