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