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 #include <asm/fixmap.h> 41 42 #define flush_HPTE(X, va, pg) _tlbie(va) 43 44 unsigned long ioremap_base; 45 unsigned long ioremap_bot; 46 EXPORT_SYMBOL(ioremap_bot); 47 48 #ifndef CONFIG_SMP 49 struct pgtable_cache_struct quicklists; 50 #endif 51 52 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 53 unsigned long flags) 54 { 55 unsigned long v, i; 56 phys_addr_t p; 57 int err; 58 59 /* 60 * Choose an address to map it to. 61 * Once the vmalloc system is running, we use it. 62 * Before then, we use space going down from ioremap_base 63 * (ioremap_bot records where we're up to). 64 */ 65 p = addr & PAGE_MASK; 66 size = PAGE_ALIGN(addr + size) - p; 67 68 /* 69 * Don't allow anybody to remap normal RAM that we're using. 70 * mem_init() sets high_memory so only do the check after that. 71 * 72 * However, allow remap of rootfs: TBD 73 */ 74 if (mem_init_done && 75 p >= memory_start && p < virt_to_phys(high_memory) && 76 !(p >= virt_to_phys((unsigned long)&__bss_stop) && 77 p < virt_to_phys((unsigned long)__bss_stop))) { 78 printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT 79 " is RAM lr %pf\n", (unsigned long)p, 80 __builtin_return_address(0)); 81 return NULL; 82 } 83 84 if (size == 0) 85 return NULL; 86 87 /* 88 * Is it already mapped? If the whole area is mapped then we're 89 * done, otherwise remap it since we want to keep the virt addrs for 90 * each request contiguous. 91 * 92 * We make the assumption here that if the bottom and top 93 * of the range we want are mapped then it's mapped to the 94 * same virt address (and this is contiguous). 95 * -- Cort 96 */ 97 98 if (mem_init_done) { 99 struct vm_struct *area; 100 area = get_vm_area(size, VM_IOREMAP); 101 if (area == NULL) 102 return NULL; 103 v = (unsigned long) area->addr; 104 } else { 105 v = (ioremap_bot -= size); 106 } 107 108 if ((flags & _PAGE_PRESENT) == 0) 109 flags |= _PAGE_KERNEL; 110 if (flags & _PAGE_NO_CACHE) 111 flags |= _PAGE_GUARDED; 112 113 err = 0; 114 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 115 err = map_page(v + i, p + i, flags); 116 if (err) { 117 if (mem_init_done) 118 vfree((void *)v); 119 return NULL; 120 } 121 122 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 123 } 124 125 void __iomem *ioremap(phys_addr_t addr, unsigned long size) 126 { 127 return __ioremap(addr, size, _PAGE_NO_CACHE); 128 } 129 EXPORT_SYMBOL(ioremap); 130 131 void iounmap(void *addr) 132 { 133 if (addr > high_memory && (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 flush_HPTE(0, va, pmd_val(*pd)); 156 /* flush_HPTE(0, va, pg); */ 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 pmd_t *pmd; 197 pte_t *pte; 198 int retval = 0; 199 200 pgd = pgd_offset(mm, addr & PAGE_MASK); 201 if (pgd) { 202 pmd = pmd_offset(pgd, addr & PAGE_MASK); 203 if (pmd_present(*pmd)) { 204 pte = pte_offset_kernel(pmd, addr & PAGE_MASK); 205 if (pte) { 206 retval = 1; 207 *ptep = pte; 208 } 209 } 210 } 211 return retval; 212 } 213 214 /* Find physical address for this virtual address. Normally used by 215 * I/O functions, but anyone can call it. 216 */ 217 unsigned long iopa(unsigned long addr) 218 { 219 unsigned long pa; 220 221 pte_t *pte; 222 struct mm_struct *mm; 223 224 /* Allow mapping of user addresses (within the thread) 225 * for DMA if necessary. 226 */ 227 if (addr < TASK_SIZE) 228 mm = current->mm; 229 else 230 mm = &init_mm; 231 232 pa = 0; 233 if (get_pteptr(mm, addr, &pte)) 234 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK); 235 236 return pa; 237 } 238 239 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, 240 unsigned long address) 241 { 242 pte_t *pte; 243 if (mem_init_done) { 244 pte = (pte_t *)__get_free_page(GFP_KERNEL | 245 __GFP_REPEAT | __GFP_ZERO); 246 } else { 247 pte = (pte_t *)early_get_page(); 248 if (pte) 249 clear_page(pte); 250 } 251 return pte; 252 } 253 254 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) 255 { 256 unsigned long address = __fix_to_virt(idx); 257 258 if (idx >= __end_of_fixed_addresses) 259 BUG(); 260 261 map_page(address, phys, pgprot_val(flags)); 262 } 263