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 #include <linux/mm_types.h> 35 36 #include <asm/pgtable.h> 37 #include <asm/pgalloc.h> 38 #include <linux/io.h> 39 #include <asm/mmu.h> 40 #include <asm/sections.h> 41 #include <asm/fixmap.h> 42 43 unsigned long ioremap_base; 44 unsigned long ioremap_bot; 45 EXPORT_SYMBOL(ioremap_bot); 46 47 #ifndef CONFIG_SMP 48 struct pgtable_cache_struct quicklists; 49 #endif 50 51 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 52 unsigned long flags) 53 { 54 unsigned long v, i; 55 phys_addr_t p; 56 int err; 57 58 /* 59 * Choose an address to map it to. 60 * Once the vmalloc system is running, we use it. 61 * Before then, we use space going down from ioremap_base 62 * (ioremap_bot records where we're up to). 63 */ 64 p = addr & PAGE_MASK; 65 size = PAGE_ALIGN(addr + size) - p; 66 67 /* 68 * Don't allow anybody to remap normal RAM that we're using. 69 * mem_init() sets high_memory so only do the check after that. 70 * 71 * However, allow remap of rootfs: TBD 72 */ 73 74 if (mem_init_done && 75 p >= memory_start && p < virt_to_phys(high_memory) && 76 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) && 77 p < __virt_to_phys((phys_addr_t)__bss_stop))) { 78 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n", 79 (unsigned long)p, __builtin_return_address(0)); 80 return NULL; 81 } 82 83 if (size == 0) 84 return NULL; 85 86 /* 87 * Is it already mapped? If the whole area is mapped then we're 88 * done, otherwise remap it since we want to keep the virt addrs for 89 * each request contiguous. 90 * 91 * We make the assumption here that if the bottom and top 92 * of the range we want are mapped then it's mapped to the 93 * same virt address (and this is contiguous). 94 * -- Cort 95 */ 96 97 if (mem_init_done) { 98 struct vm_struct *area; 99 area = get_vm_area(size, VM_IOREMAP); 100 if (area == NULL) 101 return NULL; 102 v = (unsigned long) area->addr; 103 } else { 104 v = (ioremap_bot -= size); 105 } 106 107 if ((flags & _PAGE_PRESENT) == 0) 108 flags |= _PAGE_KERNEL; 109 if (flags & _PAGE_NO_CACHE) 110 flags |= _PAGE_GUARDED; 111 112 err = 0; 113 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 114 err = map_page(v + i, p + i, flags); 115 if (err) { 116 if (mem_init_done) 117 vfree((void *)v); 118 return NULL; 119 } 120 121 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 122 } 123 124 void __iomem *ioremap(phys_addr_t addr, unsigned long size) 125 { 126 return __ioremap(addr, size, _PAGE_NO_CACHE); 127 } 128 EXPORT_SYMBOL(ioremap); 129 130 void iounmap(volatile void __iomem *addr) 131 { 132 if ((__force void *)addr > high_memory && 133 (unsigned long) addr < ioremap_bot) 134 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 135 } 136 EXPORT_SYMBOL(iounmap); 137 138 139 int map_page(unsigned long va, phys_addr_t pa, int flags) 140 { 141 pmd_t *pd; 142 pte_t *pg; 143 int err = -ENOMEM; 144 /* Use upper 10 bits of VA to index the first level map */ 145 pd = pmd_offset(pgd_offset_k(va), va); 146 /* Use middle 10 bits of VA to index the second-level map */ 147 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */ 148 /* pg = pte_alloc_kernel(&init_mm, pd, va); */ 149 150 if (pg != NULL) { 151 err = 0; 152 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 153 __pgprot(flags))); 154 if (unlikely(mem_init_done)) 155 _tlbie(va); 156 } 157 return err; 158 } 159 160 /* 161 * Map in all of physical memory starting at CONFIG_KERNEL_START. 162 */ 163 void __init mapin_ram(void) 164 { 165 unsigned long v, p, s, f; 166 167 v = CONFIG_KERNEL_START; 168 p = memory_start; 169 for (s = 0; s < lowmem_size; s += PAGE_SIZE) { 170 f = _PAGE_PRESENT | _PAGE_ACCESSED | 171 _PAGE_SHARED | _PAGE_HWEXEC; 172 if ((char *) v < _stext || (char *) v >= _etext) 173 f |= _PAGE_WRENABLE; 174 else 175 /* On the MicroBlaze, no user access 176 forces R/W kernel access */ 177 f |= _PAGE_USER; 178 map_page(v, p, f); 179 v += PAGE_SIZE; 180 p += PAGE_SIZE; 181 } 182 } 183 184 /* is x a power of 2? */ 185 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0)) 186 187 /* Scan the real Linux page tables and return a PTE pointer for 188 * a virtual address in a context. 189 * Returns true (1) if PTE was found, zero otherwise. The pointer to 190 * the PTE pointer is unmodified if PTE is not found. 191 */ 192 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep) 193 { 194 pgd_t *pgd; 195 pmd_t *pmd; 196 pte_t *pte; 197 int retval = 0; 198 199 pgd = pgd_offset(mm, addr & PAGE_MASK); 200 if (pgd) { 201 pmd = pmd_offset(pgd, addr & PAGE_MASK); 202 if (pmd_present(*pmd)) { 203 pte = pte_offset_kernel(pmd, addr & PAGE_MASK); 204 if (pte) { 205 retval = 1; 206 *ptep = pte; 207 } 208 } 209 } 210 return retval; 211 } 212 213 /* Find physical address for this virtual address. Normally used by 214 * I/O functions, but anyone can call it. 215 */ 216 unsigned long iopa(unsigned long addr) 217 { 218 unsigned long pa; 219 220 pte_t *pte; 221 struct mm_struct *mm; 222 223 /* Allow mapping of user addresses (within the thread) 224 * for DMA if necessary. 225 */ 226 if (addr < TASK_SIZE) 227 mm = current->mm; 228 else 229 mm = &init_mm; 230 231 pa = 0; 232 if (get_pteptr(mm, addr, &pte)) 233 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK); 234 235 return pa; 236 } 237 238 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm, 239 unsigned long address) 240 { 241 pte_t *pte; 242 if (mem_init_done) { 243 pte = (pte_t *)__get_free_page(GFP_KERNEL | __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