arch/m68k/mm/memory.c

   1 /*
   2  *  linux/arch/m68k/mm/memory.c
   3  *
   4  *  Copyright (C) 1995  Hamish Macdonald
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/mm.h>
   9 #include <linux/kernel.h>
  10 #include <linux/string.h>
  11 #include <linux/types.h>
  12 #include <linux/slab.h>
  13 #include <linux/init.h>
  14 #include <linux/pagemap.h>
  15
  16 #include <asm/setup.h>
  17 #include <asm/segment.h>
  18 #include <asm/page.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/system.h>
  21 #include <asm/traps.h>
  22 #include <asm/machdep.h>
  23
  24
  25 /* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
  26    struct page instead of separately kmalloced struct.  Stolen from
  27    arch/sparc/mm/srmmu.c ... */
  28
  29 typedef struct list_head ptable_desc;
  30 static LIST_HEAD(ptable_list);
  31
  32 #define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
  33 #define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
  34 #define PD_MARKBITS(dp) (*(unsigned char *)&PD_PAGE(dp)->index)
  35
  36 #define PTABLE_SIZE (PTRS_PER_PMD * sizeof(pmd_t))
  37
  38 void __init init_pointer_table(unsigned long ptable)
  39 {
  40         ptable_desc *dp;
  41         unsigned long page = ptable & PAGE_MASK;
  42         unsigned char mask = 1 << ((ptable - page)/PTABLE_SIZE);
  43
  44         dp = PD_PTABLE(page);
  45         if (!(PD_MARKBITS(dp) & mask)) {
  46                 PD_MARKBITS(dp) = 0xff;
  47                 list_add(dp, &ptable_list);
  48         }
  49
  50         PD_MARKBITS(dp) &= ~mask;
  51 #ifdef DEBUG
  52         printk("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
  53 #endif
  54
  55         /* unreserve the page so it's possible to free that page */
  56         PD_PAGE(dp)->flags &= ~(1 << PG_reserved);
  57         init_page_count(PD_PAGE(dp));
  58
  59         return;
  60 }
  61
  62 pmd_t *get_pointer_table (void)
  63 {
  64         ptable_desc *dp = ptable_list.next;
  65         unsigned char mask = PD_MARKBITS (dp);
  66         unsigned char tmp;
  67         unsigned int off;
  68
  69         /*
  70          * For a pointer table for a user process address space, a
  71          * table is taken from a page allocated for the purpose.  Each
  72          * page can hold 8 pointer tables.  The page is remapped in
  73          * virtual address space to be noncacheable.
  74          */
  75         if (mask == 0) {
  76                 void *page;
  77                 ptable_desc *new;
  78
  79                 if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
  80                         return NULL;
  81
  82                 flush_tlb_kernel_page(page);
  83                 nocache_page(page);
  84
  85                 new = PD_PTABLE(page);
  86                 PD_MARKBITS(new) = 0xfe;
  87                 list_add_tail(new, dp);
  88
  89                 return (pmd_t *)page;
  90         }
  91
  92         for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += PTABLE_SIZE)
  93                 ;
  94         PD_MARKBITS(dp) = mask & ~tmp;
  95         if (!PD_MARKBITS(dp)) {
  96                 /* move to end of list */
  97                 list_move_tail(dp, &ptable_list);
  98         }
  99         return (pmd_t *) (page_address(PD_PAGE(dp)) + off);
 100 }
 101
 102 int free_pointer_table (pmd_t *ptable)
 103 {
 104         ptable_desc *dp;
 105         unsigned long page = (unsigned long)ptable & PAGE_MASK;
 106         unsigned char mask = 1 << (((unsigned long)ptable - page)/PTABLE_SIZE);
 107
 108         dp = PD_PTABLE(page);
 109         if (PD_MARKBITS (dp) & mask)
 110                 panic ("table already free!");
 111
 112         PD_MARKBITS (dp) |= mask;
 113
 114         if (PD_MARKBITS(dp) == 0xff) {
 115                 /* all tables in page are free, free page */
 116                 list_del(dp);
 117                 cache_page((void *)page);
 118                 free_page (page);
 119                 return 1;
 120         } else if (ptable_list.next != dp) {
 121                 /*
 122                  * move this descriptor to the front of the list, since
 123                  * it has one or more free tables.
 124                  */
 125                 list_move(dp, &ptable_list);
 126         }
 127         return 0;
 128 }
 129
 130 #ifdef DEBUG_INVALID_PTOV
 131 int mm_inv_cnt = 5;
 132 #endif
 133
 134 #ifndef CONFIG_SINGLE_MEMORY_CHUNK
 135 /*
 136  * The following two routines map from a physical address to a kernel
 137  * virtual address and vice versa.
 138  */
 139 unsigned long mm_vtop(unsigned long vaddr)
 140 {
 141         int i=0;
 142         unsigned long voff = (unsigned long)vaddr - PAGE_OFFSET;
 143
 144         do {
 145                 if (voff < m68k_memory[i].size) {
 146 #ifdef DEBUGPV
 147                         printk ("VTOP(%p)=%lx\n", vaddr,
 148                                 m68k_memory[i].addr + voff);
 149 #endif
 150                         return m68k_memory[i].addr + voff;
 151                 }
 152                 voff -= m68k_memory[i].size;
 153         } while (++i < m68k_num_memory);
 154
 155         /* As a special case allow `__pa(high_memory)'.  */
 156         if (voff == 0)
 157                 return m68k_memory[i-1].addr + m68k_memory[i-1].size;
 158
 159         return -1;
 160 }
 161 EXPORT_SYMBOL(mm_vtop);
 162
 163 unsigned long mm_ptov (unsigned long paddr)
 164 {
 165         int i = 0;
 166         unsigned long poff, voff = PAGE_OFFSET;
 167
 168         do {
 169                 poff = paddr - m68k_memory[i].addr;
 170                 if (poff < m68k_memory[i].size) {
 171 #ifdef DEBUGPV
 172                         printk ("PTOV(%lx)=%lx\n", paddr, poff + voff);
 173 #endif
 174                         return poff + voff;
 175                 }
 176                 voff += m68k_memory[i].size;
 177         } while (++i < m68k_num_memory);
 178
 179 #ifdef DEBUG_INVALID_PTOV
 180         if (mm_inv_cnt > 0) {
 181                 mm_inv_cnt--;
 182                 printk("Invalid use of phys_to_virt(0x%lx) at 0x%p!\n",
 183                         paddr, __builtin_return_address(0));
 184         }
 185 #endif
 186         return -1;
 187 }
 188 EXPORT_SYMBOL(mm_ptov);
 189 #endif
 190
 191 /* invalidate page in both caches */
 192 static inline void clear040(unsigned long paddr)
 193 {
 194         asm volatile (
 195                 "nop\n\t"
 196                 ".chip 68040\n\t"
 197                 "cinvp %%bc,(%0)\n\t"
 198                 ".chip 68k"
 199                 : : "a" (paddr));
 200 }
 201
 202 /* invalidate page in i-cache */
 203 static inline void cleari040(unsigned long paddr)
 204 {
 205         asm volatile (
 206                 "nop\n\t"
 207                 ".chip 68040\n\t"
 208                 "cinvp %%ic,(%0)\n\t"
 209                 ".chip 68k"
 210                 : : "a" (paddr));
 211 }
 212
 213 /* push page in both caches */
 214 /* RZ: cpush %bc DOES invalidate %ic, regardless of DPI */
 215 static inline void push040(unsigned long paddr)
 216 {
 217         asm volatile (
 218                 "nop\n\t"
 219                 ".chip 68040\n\t"
 220                 "cpushp %%bc,(%0)\n\t"
 221                 ".chip 68k"
 222                 : : "a" (paddr));
 223 }
 224
 225 /* push and invalidate page in both caches, must disable ints
 226  * to avoid invalidating valid data */
 227 static inline void pushcl040(unsigned long paddr)
 228 {
 229         unsigned long flags;
 230
 231         local_irq_save(flags);
 232         push040(paddr);
 233         if (CPU_IS_060)
 234                 clear040(paddr);
 235         local_irq_restore(flags);
 236 }
 237
 238 /*
 239  * 040: Hit every page containing an address in the range paddr..paddr+len-1.
 240  * (Low order bits of the ea of a CINVP/CPUSHP are "don't care"s).
 241  * Hit every page until there is a page or less to go. Hit the next page,
 242  * and the one after that if the range hits it.
 243  */
 244 /* ++roman: A little bit more care is required here: The CINVP instruction
 245  * invalidates cache entries WITHOUT WRITING DIRTY DATA BACK! So the beginning
 246  * and the end of the region must be treated differently if they are not
 247  * exactly at the beginning or end of a page boundary. Else, maybe too much
 248  * data becomes invalidated and thus lost forever. CPUSHP does what we need:
 249  * it invalidates the page after pushing dirty data to memory. (Thanks to Jes
 250  * for discovering the problem!)
 251  */
 252 /* ... but on the '060, CPUSH doesn't invalidate (for us, since we have set
 253  * the DPI bit in the CACR; would it cause problems with temporarily changing
 254  * this?). So we have to push first and then additionally to invalidate.
 255  */
 256
 257
 258 /*
 259  * cache_clear() semantics: Clear any cache entries for the area in question,
 260  * without writing back dirty entries first. This is useful if the data will
 261  * be overwritten anyway, e.g. by DMA to memory. The range is defined by a
 262  * _physical_ address.
 263  */
 264
 265 void cache_clear (unsigned long paddr, int len)
 266 {
 267     if (CPU_IS_040_OR_060) {
 268         int tmp;
 269
 270         /*
 271          * We need special treatment for the first page, in case it
 272          * is not page-aligned. Page align the addresses to work
 273          * around bug I17 in the 68060.
 274          */
 275         if ((tmp = -paddr & (PAGE_SIZE - 1))) {
 276             pushcl040(paddr & PAGE_MASK);
 277             if ((len -= tmp) <= 0)
 278                 return;
 279             paddr += tmp;
 280         }
 281         tmp = PAGE_SIZE;
 282         paddr &= PAGE_MASK;
 283         while ((len -= tmp) >= 0) {
 284             clear040(paddr);
 285             paddr += tmp;
 286         }
 287         if ((len += tmp))
 288             /* a page boundary gets crossed at the end */
 289             pushcl040(paddr);
 290     }
 291     else /* 68030 or 68020 */
 292         asm volatile ("movec %/cacr,%/d0\n\t"
 293                       "oriw %0,%/d0\n\t"
 294                       "movec %/d0,%/cacr"
 295                       : : "i" (FLUSH_I_AND_D)
 296                       : "d0");
 297 #ifdef CONFIG_M68K_L2_CACHE
 298     if(mach_l2_flush)
 299         mach_l2_flush(0);
 300 #endif
 301 }
 302 EXPORT_SYMBOL(cache_clear);
 303
 304
 305 /*
 306  * cache_push() semantics: Write back any dirty cache data in the given area,
 307  * and invalidate the range in the instruction cache. It needs not (but may)
 308  * invalidate those entries also in the data cache. The range is defined by a
 309  * _physical_ address.
 310  */
 311
 312 void cache_push (unsigned long paddr, int len)
 313 {
 314     if (CPU_IS_040_OR_060) {
 315         int tmp = PAGE_SIZE;
 316
 317         /*
 318          * on 68040 or 68060, push cache lines for pages in the range;
 319          * on the '040 this also invalidates the pushed lines, but not on
 320          * the '060!
 321          */
 322         len += paddr & (PAGE_SIZE - 1);
 323
 324         /*
 325          * Work around bug I17 in the 68060 affecting some instruction
 326          * lines not being invalidated properly.
 327          */
 328         paddr &= PAGE_MASK;
 329
 330         do {
 331             push040(paddr);
 332             paddr += tmp;
 333         } while ((len -= tmp) > 0);
 334     }
 335     /*
 336      * 68030/68020 have no writeback cache. On the other hand,
 337      * cache_push is actually a superset of cache_clear (the lines
 338      * get written back and invalidated), so we should make sure
 339      * to perform the corresponding actions. After all, this is getting
 340      * called in places where we've just loaded code, or whatever, so
 341      * flushing the icache is appropriate; flushing the dcache shouldn't
 342      * be required.
 343      */
 344     else /* 68030 or 68020 */
 345         asm volatile ("movec %/cacr,%/d0\n\t"
 346                       "oriw %0,%/d0\n\t"
 347                       "movec %/d0,%/cacr"
 348                       : : "i" (FLUSH_I)
 349                       : "d0");
 350 #ifdef CONFIG_M68K_L2_CACHE
 351     if(mach_l2_flush)
 352         mach_l2_flush(1);
 353 #endif
 354 }
 355 EXPORT_SYMBOL(cache_push);
 356
 357 #ifndef CONFIG_SINGLE_MEMORY_CHUNK
 358 int mm_end_of_chunk (unsigned long addr, int len)
 359 {
 360         int i;
 361
 362         for (i = 0; i < m68k_num_memory; i++)
 363                 if (m68k_memory[i].addr + m68k_memory[i].size == addr + len)
 364                         return 1;
 365         return 0;
 366 }
 367 EXPORT_SYMBOL(mm_end_of_chunk);
 368 #endif