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/init.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/gfp.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 /* invalidate page in both caches */
 131 static inline void clear040(unsigned long paddr)
 132 {
 133         asm volatile (
 134                 "nop\n\t"
 135                 ".chip 68040\n\t"
 136                 "cinvp %%bc,(%0)\n\t"
 137                 ".chip 68k"
 138                 : : "a" (paddr));
 139 }
 140
 141 /* invalidate page in i-cache */
 142 static inline void cleari040(unsigned long paddr)
 143 {
 144         asm volatile (
 145                 "nop\n\t"
 146                 ".chip 68040\n\t"
 147                 "cinvp %%ic,(%0)\n\t"
 148                 ".chip 68k"
 149                 : : "a" (paddr));
 150 }
 151
 152 /* push page in both caches */
 153 /* RZ: cpush %bc DOES invalidate %ic, regardless of DPI */
 154 static inline void push040(unsigned long paddr)
 155 {
 156         asm volatile (
 157                 "nop\n\t"
 158                 ".chip 68040\n\t"
 159                 "cpushp %%bc,(%0)\n\t"
 160                 ".chip 68k"
 161                 : : "a" (paddr));
 162 }
 163
 164 /* push and invalidate page in both caches, must disable ints
 165  * to avoid invalidating valid data */
 166 static inline void pushcl040(unsigned long paddr)
 167 {
 168         unsigned long flags;
 169
 170         local_irq_save(flags);
 171         push040(paddr);
 172         if (CPU_IS_060)
 173                 clear040(paddr);
 174         local_irq_restore(flags);
 175 }
 176
 177 /*
 178  * 040: Hit every page containing an address in the range paddr..paddr+len-1.
 179  * (Low order bits of the ea of a CINVP/CPUSHP are "don't care"s).
 180  * Hit every page until there is a page or less to go. Hit the next page,
 181  * and the one after that if the range hits it.
 182  */
 183 /* ++roman: A little bit more care is required here: The CINVP instruction
 184  * invalidates cache entries WITHOUT WRITING DIRTY DATA BACK! So the beginning
 185  * and the end of the region must be treated differently if they are not
 186  * exactly at the beginning or end of a page boundary. Else, maybe too much
 187  * data becomes invalidated and thus lost forever. CPUSHP does what we need:
 188  * it invalidates the page after pushing dirty data to memory. (Thanks to Jes
 189  * for discovering the problem!)
 190  */
 191 /* ... but on the '060, CPUSH doesn't invalidate (for us, since we have set
 192  * the DPI bit in the CACR; would it cause problems with temporarily changing
 193  * this?). So we have to push first and then additionally to invalidate.
 194  */
 195
 196
 197 /*
 198  * cache_clear() semantics: Clear any cache entries for the area in question,
 199  * without writing back dirty entries first. This is useful if the data will
 200  * be overwritten anyway, e.g. by DMA to memory. The range is defined by a
 201  * _physical_ address.
 202  */
 203
 204 void cache_clear (unsigned long paddr, int len)
 205 {
 206     if (CPU_IS_COLDFIRE) {
 207         flush_cf_bcache(0, DCACHE_MAX_ADDR);
 208     } else if (CPU_IS_040_OR_060) {
 209         int tmp;
 210
 211         /*
 212          * We need special treatment for the first page, in case it
 213          * is not page-aligned. Page align the addresses to work
 214          * around bug I17 in the 68060.
 215          */
 216         if ((tmp = -paddr & (PAGE_SIZE - 1))) {
 217             pushcl040(paddr & PAGE_MASK);
 218             if ((len -= tmp) <= 0)
 219                 return;
 220             paddr += tmp;
 221         }
 222         tmp = PAGE_SIZE;
 223         paddr &= PAGE_MASK;
 224         while ((len -= tmp) >= 0) {
 225             clear040(paddr);
 226             paddr += tmp;
 227         }
 228         if ((len += tmp))
 229             /* a page boundary gets crossed at the end */
 230             pushcl040(paddr);
 231     }
 232     else /* 68030 or 68020 */
 233         asm volatile ("movec %/cacr,%/d0\n\t"
 234                       "oriw %0,%/d0\n\t"
 235                       "movec %/d0,%/cacr"
 236                       : : "i" (FLUSH_I_AND_D)
 237                       : "d0");
 238 #ifdef CONFIG_M68K_L2_CACHE
 239     if(mach_l2_flush)
 240         mach_l2_flush(0);
 241 #endif
 242 }
 243 EXPORT_SYMBOL(cache_clear);
 244
 245
 246 /*
 247  * cache_push() semantics: Write back any dirty cache data in the given area,
 248  * and invalidate the range in the instruction cache. It needs not (but may)
 249  * invalidate those entries also in the data cache. The range is defined by a
 250  * _physical_ address.
 251  */
 252
 253 void cache_push (unsigned long paddr, int len)
 254 {
 255     if (CPU_IS_COLDFIRE) {
 256         flush_cf_bcache(0, DCACHE_MAX_ADDR);
 257     } else if (CPU_IS_040_OR_060) {
 258         int tmp = PAGE_SIZE;
 259
 260         /*
 261          * on 68040 or 68060, push cache lines for pages in the range;
 262          * on the '040 this also invalidates the pushed lines, but not on
 263          * the '060!
 264          */
 265         len += paddr & (PAGE_SIZE - 1);
 266
 267         /*
 268          * Work around bug I17 in the 68060 affecting some instruction
 269          * lines not being invalidated properly.
 270          */
 271         paddr &= PAGE_MASK;
 272
 273         do {
 274             push040(paddr);
 275             paddr += tmp;
 276         } while ((len -= tmp) > 0);
 277     }
 278     /*
 279      * 68030/68020 have no writeback cache. On the other hand,
 280      * cache_push is actually a superset of cache_clear (the lines
 281      * get written back and invalidated), so we should make sure
 282      * to perform the corresponding actions. After all, this is getting
 283      * called in places where we've just loaded code, or whatever, so
 284      * flushing the icache is appropriate; flushing the dcache shouldn't
 285      * be required.
 286      */
 287     else /* 68030 or 68020 */
 288         asm volatile ("movec %/cacr,%/d0\n\t"
 289                       "oriw %0,%/d0\n\t"
 290                       "movec %/d0,%/cacr"
 291                       : : "i" (FLUSH_I)
 292                       : "d0");
 293 #ifdef CONFIG_M68K_L2_CACHE
 294     if(mach_l2_flush)
 295         mach_l2_flush(1);
 296 #endif
 297 }
 298 EXPORT_SYMBOL(cache_push);
 299