1/* 2 * This file contains the routines setting up the linux page tables. 3 * 4 * Copyright (C) 2008 Michal Simek 5 * Copyright (C) 2008 PetaLogix 6 * 7 * Copyright (C) 2007 Xilinx, Inc. All rights reserved. 8 * 9 * Derived from arch/ppc/mm/pgtable.c: 10 * -- paulus 11 * 12 * Derived from arch/ppc/mm/init.c: 13 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 14 * 15 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 16 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 17 * Copyright (C) 1996 Paul Mackerras 18 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk). 19 * 20 * Derived from "arch/i386/mm/init.c" 21 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 22 * 23 * This file is subject to the terms and conditions of the GNU General 24 * Public License. See the file COPYING in the main directory of this 25 * archive for more details. 26 * 27 */ 28 29#include <linux/kernel.h> 30#include <linux/module.h> 31#include <linux/types.h> 32#include <linux/vmalloc.h> 33#include <linux/init.h> 34 35#include <asm/pgtable.h> 36#include <asm/pgalloc.h> 37#include <linux/io.h> 38#include <asm/mmu.h> 39#include <asm/sections.h> 40 41#define flush_HPTE(X, va, pg) _tlbie(va) 42 43unsigned long ioremap_base; 44unsigned long ioremap_bot; 45EXPORT_SYMBOL(ioremap_bot); 46 47/* The maximum lowmem defaults to 768Mb, but this can be configured to 48 * another value. 49 */ 50#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 51 52#ifndef CONFIG_SMP 53struct pgtable_cache_struct quicklists; 54#endif 55 56static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 57 unsigned long flags) 58{ 59 unsigned long v, i; 60 phys_addr_t p; 61 int err; 62 63 /* 64 * Choose an address to map it to. 65 * Once the vmalloc system is running, we use it. 66 * Before then, we use space going down from ioremap_base 67 * (ioremap_bot records where we're up to). 68 */ 69 p = addr & PAGE_MASK; 70 size = PAGE_ALIGN(addr + size) - p; 71 72 /* 73 * Don't allow anybody to remap normal RAM that we're using. 74 * mem_init() sets high_memory so only do the check after that. 75 * 76 * However, allow remap of rootfs: TBD 77 */ 78 if (mem_init_done && 79 p >= memory_start && p < virt_to_phys(high_memory) && 80 !(p >= virt_to_phys((unsigned long)&__bss_stop) && 81 p < virt_to_phys((unsigned long)__bss_stop))) { 82 printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT 83 " is RAM lr %p\n", (unsigned long)p, 84 __builtin_return_address(0)); 85 return NULL; 86 } 87 88 if (size == 0) 89 return NULL; 90 91 /* 92 * Is it already mapped? If the whole area is mapped then we're 93 * done, otherwise remap it since we want to keep the virt addrs for 94 * each request contiguous. 95 * 96 * We make the assumption here that if the bottom and top 97 * of the range we want are mapped then it's mapped to the 98 * same virt address (and this is contiguous). 99 * -- Cort 100 */ 101 102 if (mem_init_done) { 103 struct vm_struct *area; 104 area = get_vm_area(size, VM_IOREMAP); 105 if (area == NULL) 106 return NULL; 107 v = (unsigned long) area->addr; 108 } else { 109 v = (ioremap_bot -= size); 110 } 111 112 if ((flags & _PAGE_PRESENT) == 0) 113 flags |= _PAGE_KERNEL; 114 if (flags & _PAGE_NO_CACHE) 115 flags |= _PAGE_GUARDED; 116 117 err = 0; 118 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 119 err = map_page(v + i, p + i, flags); 120 if (err) { 121 if (mem_init_done) 122 vfree((void *)v); 123 return NULL; 124 } 125 126 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 127} 128 129void __iomem *ioremap(phys_addr_t addr, unsigned long size) 130{ 131 return __ioremap(addr, size, _PAGE_NO_CACHE); 132} 133EXPORT_SYMBOL(ioremap); 134 135void iounmap(void *addr) 136{ 137 if (addr > high_memory && (unsigned long) addr < ioremap_bot) 138 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 139} 140EXPORT_SYMBOL(iounmap); 141 142 143int map_page(unsigned long va, phys_addr_t pa, int flags) 144{ 145 pmd_t *pd; 146 pte_t *pg; 147 int err = -ENOMEM; 148 /* Use upper 10 bits of VA to index the first level map */ 149 pd = pmd_offset(pgd_offset_k(va), va); 150 /* Use middle 10 bits of VA to index the second-level map */ 151 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */ 152 /* pg = pte_alloc_kernel(&init_mm, pd, va); */ 153 154 if (pg != NULL) { 155 err = 0; 156 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 157 __pgprot(flags))); 158 if (unlikely(mem_init_done)) 159 flush_HPTE(0, va, pmd_val(*pd)); 160 /* flush_HPTE(0, va, pg); */ 161 } 162 return err; 163} 164 165/* 166 * Map in all of physical memory starting at CONFIG_KERNEL_START. 167 */ 168void __init mapin_ram(void) 169{ 170 unsigned long v, p, s, f; 171 172 v = CONFIG_KERNEL_START; 173 p = memory_start; 174 for (s = 0; s < memory_size; s += PAGE_SIZE) { 175 f = _PAGE_PRESENT | _PAGE_ACCESSED | 176 _PAGE_SHARED | _PAGE_HWEXEC; 177 if ((char *) v < _stext || (char *) v >= _etext) 178 f |= _PAGE_WRENABLE; 179 else 180 /* On the MicroBlaze, no user access 181 forces R/W kernel access */ 182 f |= _PAGE_USER; 183 map_page(v, p, f); 184 v += PAGE_SIZE; 185 p += PAGE_SIZE; 186 } 187} 188 189/* is x a power of 2? */ 190#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0)) 191 192/* Scan the real Linux page tables and return a PTE pointer for 193 * a virtual address in a context. 194 * Returns true (1) if PTE was found, zero otherwise. The pointer to 195 * the PTE pointer is unmodified if PTE is not found. 196 */ 197static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep) 198{ 199 pgd_t *pgd; 200 pmd_t *pmd; 201 pte_t *pte; 202 int retval = 0; 203 204 pgd = pgd_offset(mm, addr & PAGE_MASK); 205 if (pgd) { 206 pmd = pmd_offset(pgd, addr & PAGE_MASK); 207 if (pmd_present(*pmd)) { 208 pte = pte_offset_kernel(pmd, addr & PAGE_MASK); 209 if (pte) { 210 retval = 1; 211 *ptep = pte; 212 } 213 } 214 } 215 return retval; 216} 217 218/* Find physical address for this virtual address. Normally used by 219 * I/O functions, but anyone can call it. 220 */ 221unsigned long iopa(unsigned long addr) 222{ 223 unsigned long pa; 224 225 pte_t *pte; 226 struct mm_struct *mm; 227 228 /* Allow mapping of user addresses (within the thread) 229 * for DMA if necessary. 230 */ 231 if (addr < TASK_SIZE) 232 mm = current->mm; 233 else 234 mm = &init_mm; 235 236 pa = 0; 237 if (get_pteptr(mm, addr, &pte)) 238 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK); 239 240 return pa; 241} 242 243__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, 244 unsigned long address) 245{ 246 pte_t *pte; 247 if (mem_init_done) { 248 pte = (pte_t *)__get_free_page(GFP_KERNEL | 249 __GFP_REPEAT | __GFP_ZERO); 250 } else { 251 pte = (pte_t *)early_get_page(); 252 if (pte) 253 clear_page(pte); 254 } 255 return pte; 256} 257