linux/arch/m68k/mm/motorola.c
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   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/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 */
  44unsigned long mm_cachebits;
  45EXPORT_SYMBOL(mm_cachebits);
  46#endif
  47
  48/* size of memory already mapped in head.S */
  49extern __initdata unsigned long m68k_init_mapped_size;
  50
  51extern unsigned long availmem;
  52
  53static pte_t * __init kernel_page_table(void)
  54{
  55        pte_t *ptablep;
  56
  57        ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  58
  59        clear_page(ptablep);
  60        __flush_page_to_ram(ptablep);
  61        flush_tlb_kernel_page(ptablep);
  62        nocache_page(ptablep);
  63
  64        return ptablep;
  65}
  66
  67static pmd_t *last_pgtable __initdata = NULL;
  68pmd_t *zero_pgtable __initdata = NULL;
  69
  70static pmd_t * __init kernel_ptr_table(void)
  71{
  72        if (!last_pgtable) {
  73                unsigned long pmd, last;
  74                int i;
  75
  76                /* Find the last ptr table that was used in head.S and
  77                 * reuse the remaining space in that page for further
  78                 * ptr tables.
  79                 */
  80                last = (unsigned long)kernel_pg_dir;
  81                for (i = 0; i < PTRS_PER_PGD; i++) {
  82                        if (!pgd_present(kernel_pg_dir[i]))
  83                                continue;
  84                        pmd = __pgd_page(kernel_pg_dir[i]);
  85                        if (pmd > last)
  86                                last = pmd;
  87                }
  88
  89                last_pgtable = (pmd_t *)last;
  90#ifdef DEBUG
  91                printk("kernel_ptr_init: %p\n", last_pgtable);
  92#endif
  93        }
  94
  95        last_pgtable += PTRS_PER_PMD;
  96        if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
  97                last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  98
  99                clear_page(last_pgtable);
 100                __flush_page_to_ram(last_pgtable);
 101                flush_tlb_kernel_page(last_pgtable);
 102                nocache_page(last_pgtable);
 103        }
 104
 105        return last_pgtable;
 106}
 107
 108static void __init map_node(int node)
 109{
 110#define PTRTREESIZE (256*1024)
 111#define ROOTTREESIZE (32*1024*1024)
 112        unsigned long physaddr, virtaddr, size;
 113        pgd_t *pgd_dir;
 114        pmd_t *pmd_dir;
 115        pte_t *pte_dir;
 116
 117        size = m68k_memory[node].size;
 118        physaddr = m68k_memory[node].addr;
 119        virtaddr = (unsigned long)phys_to_virt(physaddr);
 120        physaddr |= m68k_supervisor_cachemode |
 121                    _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
 122        if (CPU_IS_040_OR_060)
 123                physaddr |= _PAGE_GLOBAL040;
 124
 125        while (size > 0) {
 126#ifdef DEBUG
 127                if (!(virtaddr & (PTRTREESIZE-1)))
 128                        printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 129                                virtaddr);
 130#endif
 131                pgd_dir = pgd_offset_k(virtaddr);
 132                if (virtaddr && CPU_IS_020_OR_030) {
 133                        if (!(virtaddr & (ROOTTREESIZE-1)) &&
 134                            size >= ROOTTREESIZE) {
 135#ifdef DEBUG
 136                                printk ("[very early term]");
 137#endif
 138                                pgd_val(*pgd_dir) = physaddr;
 139                                size -= ROOTTREESIZE;
 140                                virtaddr += ROOTTREESIZE;
 141                                physaddr += ROOTTREESIZE;
 142                                continue;
 143                        }
 144                }
 145                if (!pgd_present(*pgd_dir)) {
 146                        pmd_dir = kernel_ptr_table();
 147#ifdef DEBUG
 148                        printk ("[new pointer %p]", pmd_dir);
 149#endif
 150                        pgd_set(pgd_dir, pmd_dir);
 151                } else
 152                        pmd_dir = pmd_offset(pgd_dir, virtaddr);
 153
 154                if (CPU_IS_020_OR_030) {
 155                        if (virtaddr) {
 156#ifdef DEBUG
 157                                printk ("[early term]");
 158#endif
 159                                pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
 160                                physaddr += PTRTREESIZE;
 161                        } else {
 162                                int i;
 163#ifdef DEBUG
 164                                printk ("[zero map]");
 165#endif
 166                                zero_pgtable = kernel_ptr_table();
 167                                pte_dir = (pte_t *)zero_pgtable;
 168                                pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
 169                                        _PAGE_TABLE | _PAGE_ACCESSED;
 170                                pte_val(*pte_dir++) = 0;
 171                                physaddr += PAGE_SIZE;
 172                                for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
 173                                        pte_val(*pte_dir++) = physaddr;
 174                        }
 175                        size -= PTRTREESIZE;
 176                        virtaddr += PTRTREESIZE;
 177                } else {
 178                        if (!pmd_present(*pmd_dir)) {
 179#ifdef DEBUG
 180                                printk ("[new table]");
 181#endif
 182                                pte_dir = kernel_page_table();
 183                                pmd_set(pmd_dir, pte_dir);
 184                        }
 185                        pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 186
 187                        if (virtaddr) {
 188                                if (!pte_present(*pte_dir))
 189                                        pte_val(*pte_dir) = physaddr;
 190                        } else
 191                                pte_val(*pte_dir) = 0;
 192                        size -= PAGE_SIZE;
 193                        virtaddr += PAGE_SIZE;
 194                        physaddr += PAGE_SIZE;
 195                }
 196
 197        }
 198#ifdef DEBUG
 199        printk("\n");
 200#endif
 201}
 202
 203/*
 204 * paging_init() continues the virtual memory environment setup which
 205 * was begun by the code in arch/head.S.
 206 */
 207void __init paging_init(void)
 208{
 209        unsigned long zones_size[MAX_NR_ZONES] = { 0, };
 210        unsigned long min_addr, max_addr;
 211        unsigned long addr, size, end;
 212        int i;
 213
 214#ifdef DEBUG
 215        printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
 216#endif
 217
 218        /* Fix the cache mode in the page descriptors for the 680[46]0.  */
 219        if (CPU_IS_040_OR_060) {
 220                int i;
 221#ifndef mm_cachebits
 222                mm_cachebits = _PAGE_CACHE040;
 223#endif
 224                for (i = 0; i < 16; i++)
 225                        pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
 226        }
 227
 228        min_addr = m68k_memory[0].addr;
 229        max_addr = min_addr + m68k_memory[0].size;
 230        for (i = 1; i < m68k_num_memory;) {
 231                if (m68k_memory[i].addr < min_addr) {
 232                        printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
 233                                m68k_memory[i].addr, m68k_memory[i].size);
 234                        printk("Fix your bootloader or use a memfile to make use of this area!\n");
 235                        m68k_num_memory--;
 236                        memmove(m68k_memory + i, m68k_memory + i + 1,
 237                                (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
 238                        continue;
 239                }
 240                addr = m68k_memory[i].addr + m68k_memory[i].size;
 241                if (addr > max_addr)
 242                        max_addr = addr;
 243                i++;
 244        }
 245        m68k_memoffset = min_addr - PAGE_OFFSET;
 246        m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
 247
 248        module_fixup(NULL, __start_fixup, __stop_fixup);
 249        flush_icache();
 250
 251        high_memory = phys_to_virt(max_addr);
 252
 253        min_low_pfn = availmem >> PAGE_SHIFT;
 254        max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT;
 255
 256        for (i = 0; i < m68k_num_memory; i++) {
 257                addr = m68k_memory[i].addr;
 258                end = addr + m68k_memory[i].size;
 259                m68k_setup_node(i);
 260                availmem = PAGE_ALIGN(availmem);
 261                availmem += init_bootmem_node(NODE_DATA(i),
 262                                              availmem >> PAGE_SHIFT,
 263                                              addr >> PAGE_SHIFT,
 264                                              end >> PAGE_SHIFT);
 265        }
 266
 267        /*
 268         * Map the physical memory available into the kernel virtual
 269         * address space. First initialize the bootmem allocator with
 270         * the memory we already mapped, so map_node() has something
 271         * to allocate.
 272         */
 273        addr = m68k_memory[0].addr;
 274        size = m68k_memory[0].size;
 275        free_bootmem_node(NODE_DATA(0), availmem,
 276                          min(m68k_init_mapped_size, size) - (availmem - addr));
 277        map_node(0);
 278        if (size > m68k_init_mapped_size)
 279                free_bootmem_node(NODE_DATA(0), addr + m68k_init_mapped_size,
 280                                  size - m68k_init_mapped_size);
 281
 282        for (i = 1; i < m68k_num_memory; i++)
 283                map_node(i);
 284
 285        flush_tlb_all();
 286
 287        /*
 288         * initialize the bad page table and bad page to point
 289         * to a couple of allocated pages
 290         */
 291        empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
 292
 293        /*
 294         * Set up SFC/DFC registers
 295         */
 296        set_fs(KERNEL_DS);
 297
 298#ifdef DEBUG
 299        printk ("before free_area_init\n");
 300#endif
 301        for (i = 0; i < m68k_num_memory; i++) {
 302                zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
 303                free_area_init_node(i, zones_size,
 304                                    m68k_memory[i].addr >> PAGE_SHIFT, NULL);
 305                if (node_present_pages(i))
 306                        node_set_state(i, N_NORMAL_MEMORY);
 307        }
 308}
 309
 310