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 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 48 unsigned long flags) 49 { 50 unsigned long v, i; 51 phys_addr_t p; 52 int err; 53 54 /* 55 * Choose an address to map it to. 56 * Once the vmalloc system is running, we use it. 57 * Before then, we use space going down from ioremap_base 58 * (ioremap_bot records where we're up to). 59 */ 60 p = addr & PAGE_MASK; 61 size = PAGE_ALIGN(addr + size) - p; 62 63 /* 64 * Don't allow anybody to remap normal RAM that we're using. 65 * mem_init() sets high_memory so only do the check after that. 66 * 67 * However, allow remap of rootfs: TBD 68 */ 69 70 if (mem_init_done && 71 p >= memory_start && p < virt_to_phys(high_memory) && 72 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) && 73 p < __virt_to_phys((phys_addr_t)__bss_stop))) { 74 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %ps\n", 75 (unsigned long)p, __builtin_return_address(0)); 76 return NULL; 77 } 78 79 if (size == 0) 80 return NULL; 81 82 /* 83 * Is it already mapped? If the whole area is mapped then we're 84 * done, otherwise remap it since we want to keep the virt addrs for 85 * each request contiguous. 86 * 87 * We make the assumption here that if the bottom and top 88 * of the range we want are mapped then it's mapped to the 89 * same virt address (and this is contiguous). 90 * -- Cort 91 */ 92 93 if (mem_init_done) { 94 struct vm_struct *area; 95 area = get_vm_area(size, VM_IOREMAP); 96 if (area == NULL) 97 return NULL; 98 v = (unsigned long) area->addr; 99 } else { 100 v = (ioremap_bot -= size); 101 } 102 103 if ((flags & _PAGE_PRESENT) == 0) 104 flags |= _PAGE_KERNEL; 105 if (flags & _PAGE_NO_CACHE) 106 flags |= _PAGE_GUARDED; 107 108 err = 0; 109 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 110 err = map_page(v + i, p + i, flags); 111 if (err) { 112 if (mem_init_done) 113 vfree((void *)v); 114 return NULL; 115 } 116 117 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 118 } 119 120 void __iomem *ioremap(phys_addr_t addr, unsigned long size) 121 { 122 return __ioremap(addr, size, _PAGE_NO_CACHE); 123 } 124 EXPORT_SYMBOL(ioremap); 125 126 void iounmap(volatile void __iomem *addr) 127 { 128 if ((__force void *)addr > high_memory && 129 (unsigned long) addr < ioremap_bot) 130 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 131 } 132 EXPORT_SYMBOL(iounmap); 133 134 135 int map_page(unsigned long va, phys_addr_t pa, int flags) 136 { 137 p4d_t *p4d; 138 pud_t *pud; 139 pmd_t *pd; 140 pte_t *pg; 141 int err = -ENOMEM; 142 143 /* Use upper 10 bits of VA to index the first level map */ 144 p4d = p4d_offset(pgd_offset_k(va), va); 145 pud = pud_offset(p4d, va); 146 pd = pmd_offset(pud, va); 147 /* Use middle 10 bits of VA to index the second-level map */ 148 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */ 149 /* pg = pte_alloc_kernel(&init_mm, pd, va); */ 150 151 if (pg != NULL) { 152 err = 0; 153 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 154 __pgprot(flags))); 155 if (unlikely(mem_init_done)) 156 _tlbie(va); 157 } 158 return err; 159 } 160 161 /* 162 * Map in all of physical memory starting at CONFIG_KERNEL_START. 163 */ 164 void __init mapin_ram(void) 165 { 166 unsigned long v, p, s, f; 167 168 v = CONFIG_KERNEL_START; 169 p = memory_start; 170 for (s = 0; s < lowmem_size; s += PAGE_SIZE) { 171 f = _PAGE_PRESENT | _PAGE_ACCESSED | 172 _PAGE_SHARED | _PAGE_HWEXEC; 173 if ((char *) v < _stext || (char *) v >= _etext) 174 f |= _PAGE_WRENABLE; 175 else 176 /* On the MicroBlaze, no user access 177 forces R/W kernel access */ 178 f |= _PAGE_USER; 179 map_page(v, p, f); 180 v += PAGE_SIZE; 181 p += PAGE_SIZE; 182 } 183 } 184 185 /* is x a power of 2? */ 186 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0)) 187 188 /* Scan the real Linux page tables and return a PTE pointer for 189 * a virtual address in a context. 190 * Returns true (1) if PTE was found, zero otherwise. The pointer to 191 * the PTE pointer is unmodified if PTE is not found. 192 */ 193 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep) 194 { 195 pgd_t *pgd; 196 p4d_t *p4d; 197 pud_t *pud; 198 pmd_t *pmd; 199 pte_t *pte; 200 int retval = 0; 201 202 pgd = pgd_offset(mm, addr & PAGE_MASK); 203 if (pgd) { 204 p4d = p4d_offset(pgd, addr & PAGE_MASK); 205 pud = pud_offset(p4d, addr & PAGE_MASK); 206 pmd = pmd_offset(pud, 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 */ 221 unsigned 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 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm) 244 { 245 pte_t *pte; 246 if (mem_init_done) { 247 pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 248 } else { 249 pte = (pte_t *)early_get_page(); 250 if (pte) 251 clear_page(pte); 252 } 253 return pte; 254 } 255 256 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) 257 { 258 unsigned long address = __fix_to_virt(idx); 259 260 if (idx >= __end_of_fixed_addresses) 261 BUG(); 262 263 map_page(address, phys, pgprot_val(flags)); 264 } 265