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
  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
  67 static pmd_t *last_pgtable __initdata = NULL;
  68 pmd_t *zero_pgtable __initdata = NULL;
  69
  70 static 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 *)memblock_alloc_low(PAGE_SIZE,
  98                                                            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 = memblock_alloc(PAGE_SIZE, 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