arch/powerpc/mm/ppc_mmu_32.c

   1 /*
   2  * This file contains the routines for handling the MMU on those
   3  * PowerPC implementations where the MMU substantially follows the
   4  * architecture specification.  This includes the 6xx, 7xx, 7xxx,
   5  * and 8260 implementations but excludes the 8xx and 4xx.
   6  *  -- paulus
   7  *
   8  *  Derived from arch/ppc/mm/init.c:
   9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  10  *
  11  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  12  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  13  *    Copyright (C) 1996 Paul Mackerras
  14  *
  15  *  Derived from "arch/i386/mm/init.c"
  16  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  17  *
  18  *  This program is free software; you can redistribute it and/or
  19  *  modify it under the terms of the GNU General Public License
  20  *  as published by the Free Software Foundation; either version
  21  *  2 of the License, or (at your option) any later version.
  22  *
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/mm.h>
  27 #include <linux/init.h>
  28 #include <linux/highmem.h>
  29 #include <linux/memblock.h>
  30
  31 #include <asm/prom.h>
  32 #include <asm/mmu.h>
  33 #include <asm/machdep.h>
  34
  35 #include "mmu_decl.h"
  36
  37 struct hash_pte *Hash, *Hash_end;
  38 unsigned long Hash_size, Hash_mask;
  39 unsigned long _SDR1;
  40
  41 struct ppc_bat BATS[8][2];      /* 8 pairs of IBAT, DBAT */
  42
  43 struct batrange {               /* stores address ranges mapped by BATs */
  44         unsigned long start;
  45         unsigned long limit;
  46         phys_addr_t phys;
  47 } bat_addrs[8];
  48
  49 /*
  50  * Return PA for this VA if it is mapped by a BAT, or 0
  51  */
  52 phys_addr_t v_mapped_by_bats(unsigned long va)
  53 {
  54         int b;
  55         for (b = 0; b < 4; ++b)
  56                 if (va >= bat_addrs[b].start && va < bat_addrs[b].limit)
  57                         return bat_addrs[b].phys + (va - bat_addrs[b].start);
  58         return 0;
  59 }
  60
  61 /*
  62  * Return VA for a given PA or 0 if not mapped
  63  */
  64 unsigned long p_mapped_by_bats(phys_addr_t pa)
  65 {
  66         int b;
  67         for (b = 0; b < 4; ++b)
  68                 if (pa >= bat_addrs[b].phys
  69                     && pa < (bat_addrs[b].limit-bat_addrs[b].start)
  70                               +bat_addrs[b].phys)
  71                         return bat_addrs[b].start+(pa-bat_addrs[b].phys);
  72         return 0;
  73 }
  74
  75 unsigned long __init mmu_mapin_ram(unsigned long top)
  76 {
  77         unsigned long tot, bl, done;
  78         unsigned long max_size = (256<<20);
  79
  80         if (__map_without_bats) {
  81                 printk(KERN_DEBUG "RAM mapped without BATs\n");
  82                 return 0;
  83         }
  84
  85         /* Set up BAT2 and if necessary BAT3 to cover RAM. */
  86
  87         /* Make sure we don't map a block larger than the
  88            smallest alignment of the physical address. */
  89         tot = top;
  90         for (bl = 128<<10; bl < max_size; bl <<= 1) {
  91                 if (bl * 2 > tot)
  92                         break;
  93         }
  94
  95         setbat(2, PAGE_OFFSET, 0, bl, PAGE_KERNEL_X);
  96         done = (unsigned long)bat_addrs[2].limit - PAGE_OFFSET + 1;
  97         if ((done < tot) && !bat_addrs[3].limit) {
  98                 /* use BAT3 to cover a bit more */
  99                 tot -= done;
 100                 for (bl = 128<<10; bl < max_size; bl <<= 1)
 101                         if (bl * 2 > tot)
 102                                 break;
 103                 setbat(3, PAGE_OFFSET+done, done, bl, PAGE_KERNEL_X);
 104                 done = (unsigned long)bat_addrs[3].limit - PAGE_OFFSET + 1;
 105         }
 106
 107         return done;
 108 }
 109
 110 /*
 111  * Set up one of the I/D BAT (block address translation) register pairs.
 112  * The parameters are not checked; in particular size must be a power
 113  * of 2 between 128k and 256M.
 114  */
 115 void __init setbat(int index, unsigned long virt, phys_addr_t phys,
 116                    unsigned int size, int flags)
 117 {
 118         unsigned int bl;
 119         int wimgxpp;
 120         struct ppc_bat *bat = BATS[index];
 121
 122         if ((flags & _PAGE_NO_CACHE) ||
 123             (cpu_has_feature(CPU_FTR_NEED_COHERENT) == 0))
 124                 flags &= ~_PAGE_COHERENT;
 125
 126         bl = (size >> 17) - 1;
 127         if (PVR_VER(mfspr(SPRN_PVR)) != 1) {
 128                 /* 603, 604, etc. */
 129                 /* Do DBAT first */
 130                 wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
 131                                    | _PAGE_COHERENT | _PAGE_GUARDED);
 132                 wimgxpp |= (flags & _PAGE_RW)? BPP_RW: BPP_RX;
 133                 bat[1].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */
 134                 bat[1].batl = BAT_PHYS_ADDR(phys) | wimgxpp;
 135                 if (flags & _PAGE_USER)
 136                         bat[1].batu |= 1;       /* Vp = 1 */
 137                 if (flags & _PAGE_GUARDED) {
 138                         /* G bit must be zero in IBATs */
 139                         bat[0].batu = bat[0].batl = 0;
 140                 } else {
 141                         /* make IBAT same as DBAT */
 142                         bat[0] = bat[1];
 143                 }
 144         } else {
 145                 /* 601 cpu */
 146                 if (bl > BL_8M)
 147                         bl = BL_8M;
 148                 wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
 149                                    | _PAGE_COHERENT);
 150                 wimgxpp |= (flags & _PAGE_RW)?
 151                         ((flags & _PAGE_USER)? PP_RWRW: PP_RWXX): PP_RXRX;
 152                 bat->batu = virt | wimgxpp | 4; /* Ks=0, Ku=1 */
 153                 bat->batl = phys | bl | 0x40;   /* V=1 */
 154         }
 155
 156         bat_addrs[index].start = virt;
 157         bat_addrs[index].limit = virt + ((bl + 1) << 17) - 1;
 158         bat_addrs[index].phys = phys;
 159 }
 160
 161 /*
 162  * Preload a translation in the hash table
 163  */
 164 void hash_preload(struct mm_struct *mm, unsigned long ea,
 165                   unsigned long access, unsigned long trap)
 166 {
 167         pmd_t *pmd;
 168
 169         if (Hash == 0)
 170                 return;
 171         pmd = pmd_offset(pud_offset(pgd_offset(mm, ea), ea), ea);
 172         if (!pmd_none(*pmd))
 173                 add_hash_page(mm->context.id, ea, pmd_val(*pmd));
 174 }
 175
 176 /*
 177  * Initialize the hash table and patch the instructions in hashtable.S.
 178  */
 179 void __init MMU_init_hw(void)
 180 {
 181         unsigned int hmask, mb, mb2;
 182         unsigned int n_hpteg, lg_n_hpteg;
 183
 184         extern unsigned int hash_page_patch_A[];
 185         extern unsigned int hash_page_patch_B[], hash_page_patch_C[];
 186         extern unsigned int hash_page[];
 187         extern unsigned int flush_hash_patch_A[], flush_hash_patch_B[];
 188
 189         if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
 190                 /*
 191                  * Put a blr (procedure return) instruction at the
 192                  * start of hash_page, since we can still get DSI
 193                  * exceptions on a 603.
 194                  */
 195                 hash_page[0] = 0x4e800020;
 196                 flush_icache_range((unsigned long) &hash_page[0],
 197                                    (unsigned long) &hash_page[1]);
 198                 return;
 199         }
 200
 201         if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105);
 202
 203 #define LG_HPTEG_SIZE   6               /* 64 bytes per HPTEG */
 204 #define SDR1_LOW_BITS   ((n_hpteg - 1) >> 10)
 205 #define MIN_N_HPTEG     1024            /* min 64kB hash table */
 206
 207         /*
 208          * Allow 1 HPTE (1/8 HPTEG) for each page of memory.
 209          * This is less than the recommended amount, but then
 210          * Linux ain't AIX.
 211          */
 212         n_hpteg = total_memory / (PAGE_SIZE * 8);
 213         if (n_hpteg < MIN_N_HPTEG)
 214                 n_hpteg = MIN_N_HPTEG;
 215         lg_n_hpteg = __ilog2(n_hpteg);
 216         if (n_hpteg & (n_hpteg - 1)) {
 217                 ++lg_n_hpteg;           /* round up if not power of 2 */
 218                 n_hpteg = 1 << lg_n_hpteg;
 219         }
 220         Hash_size = n_hpteg << LG_HPTEG_SIZE;
 221
 222         /*
 223          * Find some memory for the hash table.
 224          */
 225         if ( ppc_md.progress ) ppc_md.progress("hash:find piece", 0x322);
 226         Hash = __va(memblock_alloc(Hash_size, Hash_size));
 227         cacheable_memzero(Hash, Hash_size);
 228         _SDR1 = __pa(Hash) | SDR1_LOW_BITS;
 229
 230         Hash_end = (struct hash_pte *) ((unsigned long)Hash + Hash_size);
 231
 232         printk("Total memory = %lldMB; using %ldkB for hash table (at %p)\n",
 233                (unsigned long long)(total_memory >> 20), Hash_size >> 10, Hash);
 234
 235
 236         /*
 237          * Patch up the instructions in hashtable.S:create_hpte
 238          */
 239         if ( ppc_md.progress ) ppc_md.progress("hash:patch", 0x345);
 240         Hash_mask = n_hpteg - 1;
 241         hmask = Hash_mask >> (16 - LG_HPTEG_SIZE);
 242         mb2 = mb = 32 - LG_HPTEG_SIZE - lg_n_hpteg;
 243         if (lg_n_hpteg > 16)
 244                 mb2 = 16 - LG_HPTEG_SIZE;
 245
 246         hash_page_patch_A[0] = (hash_page_patch_A[0] & ~0xffff)
 247                 | ((unsigned int)(Hash) >> 16);
 248         hash_page_patch_A[1] = (hash_page_patch_A[1] & ~0x7c0) | (mb << 6);
 249         hash_page_patch_A[2] = (hash_page_patch_A[2] & ~0x7c0) | (mb2 << 6);
 250         hash_page_patch_B[0] = (hash_page_patch_B[0] & ~0xffff) | hmask;
 251         hash_page_patch_C[0] = (hash_page_patch_C[0] & ~0xffff) | hmask;
 252
 253         /*
 254          * Ensure that the locations we've patched have been written
 255          * out from the data cache and invalidated in the instruction
 256          * cache, on those machines with split caches.
 257          */
 258         flush_icache_range((unsigned long) &hash_page_patch_A[0],
 259                            (unsigned long) &hash_page_patch_C[1]);
 260
 261         /*
 262          * Patch up the instructions in hashtable.S:flush_hash_page
 263          */
 264         flush_hash_patch_A[0] = (flush_hash_patch_A[0] & ~0xffff)
 265                 | ((unsigned int)(Hash) >> 16);
 266         flush_hash_patch_A[1] = (flush_hash_patch_A[1] & ~0x7c0) | (mb << 6);
 267         flush_hash_patch_A[2] = (flush_hash_patch_A[2] & ~0x7c0) | (mb2 << 6);
 268         flush_hash_patch_B[0] = (flush_hash_patch_B[0] & ~0xffff) | hmask;
 269         flush_icache_range((unsigned long) &flush_hash_patch_A[0],
 270                            (unsigned long) &flush_hash_patch_B[1]);
 271
 272         if ( ppc_md.progress ) ppc_md.progress("hash:done", 0x205);
 273 }
 274
 275 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 276                                 phys_addr_t first_memblock_size)
 277 {
 278         /* We don't currently support the first MEMBLOCK not mapping 0
 279          * physical on those processors
 280          */
 281         BUG_ON(first_memblock_base != 0);
 282
 283         /* 601 can only access 16MB at the moment */
 284         if (PVR_VER(mfspr(SPRN_PVR)) == 1)
 285                 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01000000));
 286         else /* Anything else has 256M mapped */
 287                 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x10000000));
 288 }