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/export.h> 30 #include <linux/kernel.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 #include <asm/fixmap.h> 41 42 unsigned long ioremap_base; 43 unsigned long ioremap_bot; 44 EXPORT_SYMBOL(ioremap_bot); 45 46 #ifndef CONFIG_SMP 47 struct pgtable_cache_struct quicklists; 48 #endif 49 50 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 51 unsigned long flags) 52 { 53 unsigned long v, i; 54 phys_addr_t p; 55 int err; 56 57 /* 58 * Choose an address to map it to. 59 * Once the vmalloc system is running, we use it. 60 * Before then, we use space going down from ioremap_base 61 * (ioremap_bot records where we're up to). 62 */ 63 p = addr & PAGE_MASK; 64 size = PAGE_ALIGN(addr + size) - p; 65 66 /* 67 * Don't allow anybody to remap normal RAM that we're using. 68 * mem_init() sets high_memory so only do the check after that. 69 * 70 * However, allow remap of rootfs: TBD 71 */ 72 73 if (mem_init_done && 74 p >= memory_start && p < virt_to_phys(high_memory) && 75 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) && 76 p < __virt_to_phys((phys_addr_t)__bss_stop))) { 77 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n", 78 (unsigned long)p, __builtin_return_address(0)); 79 return NULL; 80 } 81 82 if (size == 0) 83 return NULL; 84 85 /* 86 * Is it already mapped? If the whole area is mapped then we're 87 * done, otherwise remap it since we want to keep the virt addrs for 88 * each request contiguous. 89 * 90 * We make the assumption here that if the bottom and top 91 * of the range we want are mapped then it's mapped to the 92 * same virt address (and this is contiguous). 93 * -- Cort 94 */ 95 96 if (mem_init_done) { 97 struct vm_struct *area; 98 area = get_vm_area(size, VM_IOREMAP); 99 if (area == NULL) 100 return NULL; 101 v = (unsigned long) area->addr; 102 } else { 103 v = (ioremap_bot -= size); 104 } 105 106 if ((flags & _PAGE_PRESENT) == 0) 107 flags |= _PAGE_KERNEL; 108 if (flags & _PAGE_NO_CACHE) 109 flags |= _PAGE_GUARDED; 110 111 err = 0; 112 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 113 err = map_page(v + i, p + i, flags); 114 if (err) { 115 if (mem_init_done) 116 vfree((void *)v); 117 return NULL; 118 } 119 120 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 121 } 122 123 void __iomem *ioremap(phys_addr_t addr, unsigned long size) 124 { 125 return __ioremap(addr, size, _PAGE_NO_CACHE); 126 } 127 EXPORT_SYMBOL(ioremap); 128 129 void iounmap(void __iomem *addr) 130 { 131 if ((__force void *)addr > high_memory && 132 (unsigned long) addr < ioremap_bot) 133 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 134 } 135 EXPORT_SYMBOL(iounmap); 136 137 138 int map_page(unsigned long va, phys_addr_t pa, int flags) 139 { 140 pmd_t *pd; 141 pte_t *pg; 142 int err = -ENOMEM; 143 /* Use upper 10 bits of VA to index the first level map */ 144 pd = pmd_offset(pgd_offset_k(va), va); 145 /* Use middle 10 bits of VA to index the second-level map */ 146 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */ 147 /* pg = pte_alloc_kernel(&init_mm, pd, va); */ 148 149 if (pg != NULL) { 150 err = 0; 151 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 152 __pgprot(flags))); 153 if (unlikely(mem_init_done)) 154 _tlbie(va); 155 } 156 return err; 157 } 158 159 /* 160 * Map in all of physical memory starting at CONFIG_KERNEL_START. 161 */ 162 void __init mapin_ram(void) 163 { 164 unsigned long v, p, s, f; 165 166 v = CONFIG_KERNEL_START; 167 p = memory_start; 168 for (s = 0; s < lowmem_size; s += PAGE_SIZE) { 169 f = _PAGE_PRESENT | _PAGE_ACCESSED | 170 _PAGE_SHARED | _PAGE_HWEXEC; 171 if ((char *) v < _stext || (char *) v >= _etext) 172 f |= _PAGE_WRENABLE; 173 else 174 /* On the MicroBlaze, no user access 175 forces R/W kernel access */ 176 f |= _PAGE_USER; 177 map_page(v, p, f); 178 v += PAGE_SIZE; 179 p += PAGE_SIZE; 180 } 181 } 182 183 /* is x a power of 2? */ 184 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0)) 185 186 /* Scan the real Linux page tables and return a PTE pointer for 187 * a virtual address in a context. 188 * Returns true (1) if PTE was found, zero otherwise. The pointer to 189 * the PTE pointer is unmodified if PTE is not found. 190 */ 191 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep) 192 { 193 pgd_t *pgd; 194 pmd_t *pmd; 195 pte_t *pte; 196 int retval = 0; 197 198 pgd = pgd_offset(mm, addr & PAGE_MASK); 199 if (pgd) { 200 pmd = pmd_offset(pgd, addr & PAGE_MASK); 201 if (pmd_present(*pmd)) { 202 pte = pte_offset_kernel(pmd, addr & PAGE_MASK); 203 if (pte) { 204 retval = 1; 205 *ptep = pte; 206 } 207 } 208 } 209 return retval; 210 } 211 212 /* Find physical address for this virtual address. Normally used by 213 * I/O functions, but anyone can call it. 214 */ 215 unsigned long iopa(unsigned long addr) 216 { 217 unsigned long pa; 218 219 pte_t *pte; 220 struct mm_struct *mm; 221 222 /* Allow mapping of user addresses (within the thread) 223 * for DMA if necessary. 224 */ 225 if (addr < TASK_SIZE) 226 mm = current->mm; 227 else 228 mm = &init_mm; 229 230 pa = 0; 231 if (get_pteptr(mm, addr, &pte)) 232 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK); 233 234 return pa; 235 } 236 237 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, 238 unsigned long address) 239 { 240 pte_t *pte; 241 if (mem_init_done) { 242 pte = (pte_t *)__get_free_page(GFP_KERNEL | 243 __GFP_REPEAT | __GFP_ZERO); 244 } else { 245 pte = (pte_t *)early_get_page(); 246 if (pte) 247 clear_page(pte); 248 } 249 return pte; 250 } 251 252 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) 253 { 254 unsigned long address = __fix_to_virt(idx); 255 256 if (idx >= __end_of_fixed_addresses) 257 BUG(); 258 259 map_page(address, phys, pgprot_val(flags)); 260 } 261