- 根目录:
- arch
- powerpc
- mm
- ppc_mmu_32.c
/*
* This file contains the routines for handling the MMU on those
* PowerPC implementations where the MMU substantially follows the
* architecture specification. This includes the 6xx, 7xx, 7xxx,
* and 8260 implementations but excludes the 8xx and 4xx.
* -- paulus
*
* Derived from arch/ppc/mm/init.c:
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
* and Cort Dougan (PReP) (cort@cs.nmt.edu)
* Copyright (C) 1996 Paul Mackerras
*
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <asm/prom.h>
#include <asm/mmu.h>
#include <asm/machdep.h>
#include "mmu_decl.h"
struct hash_pte *Hash, *Hash_end;
unsigned long Hash_size, Hash_mask;
unsigned long _SDR1;
struct ppc_bat BATS[8][2]; /* 8 pairs of IBAT, DBAT */
struct batrange { /* stores address ranges mapped by BATs */
unsigned long start;
unsigned long limit;
phys_addr_t phys;
} bat_addrs[8];
/*
* Return PA for this VA if it is mapped by a BAT, or 0
*/
phys_addr_t v_mapped_by_bats(unsigned long va)
{
int b;
for (b = 0; b < 4; ++b)
if (va >= bat_addrs[b].start && va < bat_addrs[b].limit)
return bat_addrs[b].phys + (va - bat_addrs[b].start);
return 0;
}
/*
* Return VA for a given PA or 0 if not mapped
*/
unsigned long p_mapped_by_bats(phys_addr_t pa)
{
int b;
for (b = 0; b < 4; ++b)
if (pa >= bat_addrs[b].phys
&& pa < (bat_addrs[b].limit-bat_addrs[b].start)
+bat_addrs[b].phys)
return bat_addrs[b].start+(pa-bat_addrs[b].phys);
return 0;
}
unsigned long __init mmu_mapin_ram(unsigned long top)
{
unsigned long tot, bl, done;
unsigned long max_size = (256<<20);
if (__map_without_bats) {
printk(KERN_DEBUG "RAM mapped without BATs\n");
return 0;
}
/* Set up BAT2 and if necessary BAT3 to cover RAM. */
/* Make sure we don't map a block larger than the
smallest alignment of the physical address. */
tot = top;
for (bl = 128<<10; bl < max_size; bl <<= 1) {
if (bl * 2 > tot)
break;
}
setbat(2, PAGE_OFFSET, 0, bl, PAGE_KERNEL_X);
done = (unsigned long)bat_addrs[2].limit - PAGE_OFFSET + 1;
if ((done < tot) && !bat_addrs[3].limit) {
/* use BAT3 to cover a bit more */
tot -= done;
for (bl = 128<<10; bl < max_size; bl <<= 1)
if (bl * 2 > tot)
break;
setbat(3, PAGE_OFFSET+done, done, bl, PAGE_KERNEL_X);
done = (unsigned long)bat_addrs[3].limit - PAGE_OFFSET + 1;
}
return done;
}
/*
* Set up one of the I/D BAT (block address translation) register pairs.
* The parameters are not checked; in particular size must be a power
* of 2 between 128k and 256M.
*/
void __init setbat(int index, unsigned long virt, phys_addr_t phys,
unsigned int size, pgprot_t prot)
{
unsigned int bl;
int wimgxpp;
struct ppc_bat *bat = BATS[index];
unsigned long flags = pgprot_val(prot);
if ((flags & _PAGE_NO_CACHE) ||
(cpu_has_feature(CPU_FTR_NEED_COHERENT) == 0))
flags &= ~_PAGE_COHERENT;
bl = (size >> 17) - 1;
if (PVR_VER(mfspr(SPRN_PVR)) != 1) {
/* 603, 604, etc. */
/* Do DBAT first */
wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
| _PAGE_COHERENT | _PAGE_GUARDED);
wimgxpp |= (flags & _PAGE_RW)? BPP_RW: BPP_RX;
bat[1].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */
bat[1].batl = BAT_PHYS_ADDR(phys) | wimgxpp;
if (flags & _PAGE_USER)
bat[1].batu |= 1; /* Vp = 1 */
if (flags & _PAGE_GUARDED) {
/* G bit must be zero in IBATs */
bat[0].batu = bat[0].batl = 0;
} else {
/* make IBAT same as DBAT */
bat[0] = bat[1];
}
} else {
/* 601 cpu */
if (bl > BL_8M)
bl = BL_8M;
wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
| _PAGE_COHERENT);
wimgxpp |= (flags & _PAGE_RW)?
((flags & _PAGE_USER)? PP_RWRW: PP_RWXX): PP_RXRX;
bat->batu = virt | wimgxpp | 4; /* Ks=0, Ku=1 */
bat->batl = phys | bl | 0x40; /* V=1 */
}
bat_addrs[index].start = virt;
bat_addrs[index].limit = virt + ((bl + 1) << 17) - 1;
bat_addrs[index].phys = phys;
}
/*
* Preload a translation in the hash table
*/
void hash_preload(struct mm_struct *mm, unsigned long ea,
unsigned long access, unsigned long trap)
{
pmd_t *pmd;
if (Hash == 0)
return;
pmd = pmd_offset(pud_offset(pgd_offset(mm, ea), ea), ea);
if (!pmd_none(*pmd))
add_hash_page(mm->context.id, ea, pmd_val(*pmd));
}
/*
* Initialize the hash table and patch the instructions in hashtable.S.
*/
void __init MMU_init_hw(void)
{
unsigned int hmask, mb, mb2;
unsigned int n_hpteg, lg_n_hpteg;
extern unsigned int hash_page_patch_A[];
extern unsigned int hash_page_patch_B[], hash_page_patch_C[];
extern unsigned int hash_page[];
extern unsigned int flush_hash_patch_A[], flush_hash_patch_B[];
if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
/*
* Put a blr (procedure return) instruction at the
* start of hash_page, since we can still get DSI
* exceptions on a 603.
*/
hash_page[0] = 0x4e800020;
flush_icache_range((unsigned long) &hash_page[0],
(unsigned long) &hash_page[1]);
return;
}
if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105);
#define LG_HPTEG_SIZE 6 /* 64 bytes per HPTEG */
#define SDR1_LOW_BITS ((n_hpteg - 1) >> 10)
#define MIN_N_HPTEG 1024 /* min 64kB hash table */
/*
* Allow 1 HPTE (1/8 HPTEG) for each page of memory.
* This is less than the recommended amount, but then
* Linux ain't AIX.
*/
n_hpteg = total_memory / (PAGE_SIZE * 8);
if (n_hpteg < MIN_N_HPTEG)
n_hpteg = MIN_N_HPTEG;
lg_n_hpteg = __ilog2(n_hpteg);
if (n_hpteg & (n_hpteg - 1)) {
++lg_n_hpteg; /* round up if not power of 2 */
n_hpteg = 1 << lg_n_hpteg;
}
Hash_size = n_hpteg << LG_HPTEG_SIZE;
/*
* Find some memory for the hash table.
*/
if ( ppc_md.progress ) ppc_md.progress("hash:find piece", 0x322);
Hash = __va(memblock_alloc(Hash_size, Hash_size));
memset(Hash, 0, Hash_size);
_SDR1 = __pa(Hash) | SDR1_LOW_BITS;
Hash_end = (struct hash_pte *) ((unsigned long)Hash + Hash_size);
printk("Total memory = %lldMB; using %ldkB for hash table (at %p)\n",
(unsigned long long)(total_memory >> 20), Hash_size >> 10, Hash);
/*
* Patch up the instructions in hashtable.S:create_hpte
*/
if ( ppc_md.progress ) ppc_md.progress("hash:patch", 0x345);
Hash_mask = n_hpteg - 1;
hmask = Hash_mask >> (16 - LG_HPTEG_SIZE);
mb2 = mb = 32 - LG_HPTEG_SIZE - lg_n_hpteg;
if (lg_n_hpteg > 16)
mb2 = 16 - LG_HPTEG_SIZE;
hash_page_patch_A[0] = (hash_page_patch_A[0] & ~0xffff)
| ((unsigned int)(Hash) >> 16);
hash_page_patch_A[1] = (hash_page_patch_A[1] & ~0x7c0) | (mb << 6);
hash_page_patch_A[2] = (hash_page_patch_A[2] & ~0x7c0) | (mb2 << 6);
hash_page_patch_B[0] = (hash_page_patch_B[0] & ~0xffff) | hmask;
hash_page_patch_C[0] = (hash_page_patch_C[0] & ~0xffff) | hmask;
/*
* Ensure that the locations we've patched have been written
* out from the data cache and invalidated in the instruction
* cache, on those machines with split caches.
*/
flush_icache_range((unsigned long) &hash_page_patch_A[0],
(unsigned long) &hash_page_patch_C[1]);
/*
* Patch up the instructions in hashtable.S:flush_hash_page
*/
flush_hash_patch_A[0] = (flush_hash_patch_A[0] & ~0xffff)
| ((unsigned int)(Hash) >> 16);
flush_hash_patch_A[1] = (flush_hash_patch_A[1] & ~0x7c0) | (mb << 6);
flush_hash_patch_A[2] = (flush_hash_patch_A[2] & ~0x7c0) | (mb2 << 6);
flush_hash_patch_B[0] = (flush_hash_patch_B[0] & ~0xffff) | hmask;
flush_icache_range((unsigned long) &flush_hash_patch_A[0],
(unsigned long) &flush_hash_patch_B[1]);
if ( ppc_md.progress ) ppc_md.progress("hash:done", 0x205);
}
void setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size)
{
/* We don't currently support the first MEMBLOCK not mapping 0
* physical on those processors
*/
BUG_ON(first_memblock_base != 0);
/* 601 can only access 16MB at the moment */
if (PVR_VER(mfspr(SPRN_PVR)) == 1)
memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01000000));
else /* Anything else has 256M mapped */
memblock_set_current_limit(min_t(u64, first_memblock_size, 0x10000000));
}