arch/m68k/mm/memory.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/m68k/mm/memory.c
   4  *
   5  *  Copyright (C) 1995  Hamish Macdonald
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/mm.h>
  10 #include <linux/kernel.h>
  11 #include <linux/string.h>
  12 #include <linux/types.h>
  13 #include <linux/init.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/gfp.h>
  16
  17 #include <asm/setup.h>
  18 #include <asm/segment.h>
  19 #include <asm/page.h>
  20 #include <asm/pgalloc.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         pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
  52
  53         /* unreserve the page so it's possible to free that page */
  54         __ClearPageReserved(PD_PAGE(dp));
  55         init_page_count(PD_PAGE(dp));
  56
  57         return;
  58 }
  59
  60 pmd_t *get_pointer_table (void)
  61 {
  62         ptable_desc *dp = ptable_list.next;
  63         unsigned char mask = PD_MARKBITS (dp);
  64         unsigned char tmp;
  65         unsigned int off;
  66
  67         /*
  68          * For a pointer table for a user process address space, a
  69          * table is taken from a page allocated for the purpose.  Each
  70          * page can hold 8 pointer tables.  The page is remapped in
  71          * virtual address space to be noncacheable.
  72          */
  73         if (mask == 0) {
  74                 void *page;
  75                 ptable_desc *new;
  76
  77                 if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
  78                         return NULL;
  79
  80                 flush_tlb_kernel_page(page);
  81                 nocache_page(page);
  82
  83                 new = PD_PTABLE(page);
  84                 PD_MARKBITS(new) = 0xfe;
  85                 list_add_tail(new, dp);
  86
  87                 return (pmd_t *)page;
  88         }
  89
  90         for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += PTABLE_SIZE)
  91                 ;
  92         PD_MARKBITS(dp) = mask & ~tmp;
  93         if (!PD_MARKBITS(dp)) {
  94                 /* move to end of list */
  95                 list_move_tail(dp, &ptable_list);
  96         }
  97         return (pmd_t *) (page_address(PD_PAGE(dp)) + off);
  98 }
  99
 100 int free_pointer_table (pmd_t *ptable)
 101 {
 102         ptable_desc *dp;
 103         unsigned long page = (unsigned long)ptable & PAGE_MASK;
 104         unsigned char mask = 1 << (((unsigned long)ptable - page)/PTABLE_SIZE);
 105
 106         dp = PD_PTABLE(page);
 107         if (PD_MARKBITS (dp) & mask)
 108                 panic ("table already free!");
 109
 110         PD_MARKBITS (dp) |= mask;
 111
 112         if (PD_MARKBITS(dp) == 0xff) {
 113                 /* all tables in page are free, free page */
 114                 list_del(dp);
 115                 cache_page((void *)page);
 116                 free_page (page);
 117                 return 1;
 118         } else if (ptable_list.next != dp) {
 119                 /*
 120                  * move this descriptor to the front of the list, since
 121                  * it has one or more free tables.
 122                  */
 123                 list_move(dp, &ptable_list);
 124         }
 125         return 0;
 126 }
 127
 128 /* invalidate page in both caches */
 129 static inline void clear040(unsigned long paddr)
 130 {
 131         asm volatile (
 132                 "nop\n\t"
 133                 ".chip 68040\n\t"
 134                 "cinvp %%bc,(%0)\n\t"
 135                 ".chip 68k"
 136                 : : "a" (paddr));
 137 }
 138
 139 /* invalidate page in i-cache */
 140 static inline void cleari040(unsigned long paddr)
 141 {
 142         asm volatile (
 143                 "nop\n\t"
 144                 ".chip 68040\n\t"
 145                 "cinvp %%ic,(%0)\n\t"
 146                 ".chip 68k"
 147                 : : "a" (paddr));
 148 }
 149
 150 /* push page in both caches */
 151 /* RZ: cpush %bc DOES invalidate %ic, regardless of DPI */
 152 static inline void push040(unsigned long paddr)
 153 {
 154         asm volatile (
 155                 "nop\n\t"
 156                 ".chip 68040\n\t"
 157                 "cpushp %%bc,(%0)\n\t"
 158                 ".chip 68k"
 159                 : : "a" (paddr));
 160 }
 161
 162 /* push and invalidate page in both caches, must disable ints
 163  * to avoid invalidating valid data */
 164 static inline void pushcl040(unsigned long paddr)
 165 {
 166         unsigned long flags;
 167
 168         local_irq_save(flags);
 169         push040(paddr);
 170         if (CPU_IS_060)
 171                 clear040(paddr);
 172         local_irq_restore(flags);
 173 }
 174
 175 /*
 176  * 040: Hit every page containing an address in the range paddr..paddr+len-1.
 177  * (Low order bits of the ea of a CINVP/CPUSHP are "don't care"s).
 178  * Hit every page until there is a page or less to go. Hit the next page,
 179  * and the one after that if the range hits it.
 180  */
 181 /* ++roman: A little bit more care is required here: The CINVP instruction
 182  * invalidates cache entries WITHOUT WRITING DIRTY DATA BACK! So the beginning
 183  * and the end of the region must be treated differently if they are not
 184  * exactly at the beginning or end of a page boundary. Else, maybe too much
 185  * data becomes invalidated and thus lost forever. CPUSHP does what we need:
 186  * it invalidates the page after pushing dirty data to memory. (Thanks to Jes
 187  * for discovering the problem!)
 188  */
 189 /* ... but on the '060, CPUSH doesn't invalidate (for us, since we have set
 190  * the DPI bit in the CACR; would it cause problems with temporarily changing
 191  * this?). So we have to push first and then additionally to invalidate.
 192  */
 193
 194
 195 /*
 196  * cache_clear() semantics: Clear any cache entries for the area in question,
 197  * without writing back dirty entries first. This is useful if the data will
 198  * be overwritten anyway, e.g. by DMA to memory. The range is defined by a
 199  * _physical_ address.
 200  */
 201
 202 void cache_clear (unsigned long paddr, int len)
 203 {
 204     if (CPU_IS_COLDFIRE) {
 205         clear_cf_bcache(0, DCACHE_MAX_ADDR);
 206     } else if (CPU_IS_040_OR_060) {
 207         int tmp;
 208
 209         /*
 210          * We need special treatment for the first page, in case it
 211          * is not page-aligned. Page align the addresses to work
 212          * around bug I17 in the 68060.
 213          */
 214         if ((tmp = -paddr & (PAGE_SIZE - 1))) {
 215             pushcl040(paddr & PAGE_MASK);
 216             if ((len -= tmp) <= 0)
 217                 return;
 218             paddr += tmp;
 219         }
 220         tmp = PAGE_SIZE;
 221         paddr &= PAGE_MASK;
 222         while ((len -= tmp) >= 0) {
 223             clear040(paddr);
 224             paddr += tmp;
 225         }
 226         if ((len += tmp))
 227             /* a page boundary gets crossed at the end */
 228             pushcl040(paddr);
 229     }
 230     else /* 68030 or 68020 */
 231         asm volatile ("movec %/cacr,%/d0\n\t"
 232                       "oriw %0,%/d0\n\t"
 233                       "movec %/d0,%/cacr"
 234                       : : "i" (FLUSH_I_AND_D)
 235                       : "d0");
 236 #ifdef CONFIG_M68K_L2_CACHE
 237     if(mach_l2_flush)
 238         mach_l2_flush(0);
 239 #endif
 240 }
 241 EXPORT_SYMBOL(cache_clear);
 242
 243
 244 /*
 245  * cache_push() semantics: Write back any dirty cache data in the given area,
 246  * and invalidate the range in the instruction cache. It needs not (but may)
 247  * invalidate those entries also in the data cache. The range is defined by a
 248  * _physical_ address.
 249  */
 250
 251 void cache_push (unsigned long paddr, int len)
 252 {
 253     if (CPU_IS_COLDFIRE) {
 254         flush_cf_bcache(0, DCACHE_MAX_ADDR);
 255     } else if (CPU_IS_040_OR_060) {
 256         int tmp = PAGE_SIZE;
 257
 258         /*
 259          * on 68040 or 68060, push cache lines for pages in the range;
 260          * on the '040 this also invalidates the pushed lines, but not on
 261          * the '060!
 262          */
 263         len += paddr & (PAGE_SIZE - 1);
 264
 265         /*
 266          * Work around bug I17 in the 68060 affecting some instruction
 267          * lines not being invalidated properly.
 268          */
 269         paddr &= PAGE_MASK;
 270
 271         do {
 272             push040(paddr);
 273             paddr += tmp;
 274         } while ((len -= tmp) > 0);
 275     }
 276     /*
 277      * 68030/68020 have no writeback cache. On the other hand,
 278      * cache_push is actually a superset of cache_clear (the lines
 279      * get written back and invalidated), so we should make sure
 280      * to perform the corresponding actions. After all, this is getting
 281      * called in places where we've just loaded code, or whatever, so
 282      * flushing the icache is appropriate; flushing the dcache shouldn't
 283      * be required.
 284      */
 285     else /* 68030 or 68020 */
 286         asm volatile ("movec %/cacr,%/d0\n\t"
 287                       "oriw %0,%/d0\n\t"
 288                       "movec %/d0,%/cacr"
 289                       : : "i" (FLUSH_I)
 290                       : "d0");
 291 #ifdef CONFIG_M68K_L2_CACHE
 292     if(mach_l2_flush)
 293         mach_l2_flush(1);
 294 #endif
 295 }
 296 EXPORT_SYMBOL(cache_push);
 297