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 #include <linux/pgtable.h> 36 #include <linux/memblock.h> 37 38 #include <asm/pgalloc.h> 39 #include <linux/io.h> 40 #include <asm/mmu.h> 41 #include <asm/sections.h> 42 #include <asm/fixmap.h> 43 44 unsigned long ioremap_base; 45 unsigned long ioremap_bot; 46 EXPORT_SYMBOL(ioremap_bot); 47 48 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 49 unsigned long flags) 50 { 51 unsigned long v, i; 52 phys_addr_t p; 53 int err; 54 55 /* 56 * Choose an address to map it to. 57 * Once the vmalloc system is running, we use it. 58 * Before then, we use space going down from ioremap_base 59 * (ioremap_bot records where we're up to). 60 */ 61 p = addr & PAGE_MASK; 62 size = PAGE_ALIGN(addr + size) - p; 63 64 /* 65 * Don't allow anybody to remap normal RAM that we're using. 66 * mem_init() sets high_memory so only do the check after that. 67 * 68 * However, allow remap of rootfs: TBD 69 */ 70 71 if (mem_init_done && 72 p >= memory_start && p < virt_to_phys(high_memory) && 73 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) && 74 p < __virt_to_phys((phys_addr_t)__bss_stop))) { 75 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %ps\n", 76 (unsigned long)p, __builtin_return_address(0)); 77 return NULL; 78 } 79 80 if (size == 0) 81 return NULL; 82 83 /* 84 * Is it already mapped? If the whole area is mapped then we're 85 * done, otherwise remap it since we want to keep the virt addrs for 86 * each request contiguous. 87 * 88 * We make the assumption here that if the bottom and top 89 * of the range we want are mapped then it's mapped to the 90 * same virt address (and this is contiguous). 91 * -- Cort 92 */ 93 94 if (mem_init_done) { 95 struct vm_struct *area; 96 area = get_vm_area(size, VM_IOREMAP); 97 if (area == NULL) 98 return NULL; 99 v = (unsigned long) area->addr; 100 } else { 101 v = (ioremap_bot -= size); 102 } 103 104 if ((flags & _PAGE_PRESENT) == 0) 105 flags |= _PAGE_KERNEL; 106 if (flags & _PAGE_NO_CACHE) 107 flags |= _PAGE_GUARDED; 108 109 err = 0; 110 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 111 err = map_page(v + i, p + i, flags); 112 if (err) { 113 if (mem_init_done) 114 vfree((void *)v); 115 return NULL; 116 } 117 118 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 119 } 120 121 void __iomem *ioremap(phys_addr_t addr, unsigned long size) 122 { 123 return __ioremap(addr, size, _PAGE_NO_CACHE); 124 } 125 EXPORT_SYMBOL(ioremap); 126 127 void iounmap(volatile void __iomem *addr) 128 { 129 if ((__force void *)addr > high_memory && 130 (unsigned long) addr < ioremap_bot) 131 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 132 } 133 EXPORT_SYMBOL(iounmap); 134 135 136 int map_page(unsigned long va, phys_addr_t pa, int flags) 137 { 138 p4d_t *p4d; 139 pud_t *pud; 140 pmd_t *pd; 141 pte_t *pg; 142 int err = -ENOMEM; 143 144 /* Use upper 10 bits of VA to index the first level map */ 145 p4d = p4d_offset(pgd_offset_k(va), va); 146 pud = pud_offset(p4d, va); 147 pd = pmd_offset(pud, va); 148 /* Use middle 10 bits of VA to index the second-level map */ 149 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */ 150 /* pg = pte_alloc_kernel(&init_mm, pd, va); */ 151 152 if (pg != NULL) { 153 err = 0; 154 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 155 __pgprot(flags))); 156 if (unlikely(mem_init_done)) 157 _tlbie(va); 158 } 159 return err; 160 } 161 162 /* 163 * Map in all of physical memory starting at CONFIG_KERNEL_START. 164 */ 165 void __init mapin_ram(void) 166 { 167 unsigned long v, p, s, f; 168 169 v = CONFIG_KERNEL_START; 170 p = memory_start; 171 for (s = 0; s < lowmem_size; s += PAGE_SIZE) { 172 f = _PAGE_PRESENT | _PAGE_ACCESSED | 173 _PAGE_SHARED | _PAGE_HWEXEC; 174 if ((char *) v < _stext || (char *) v >= _etext) 175 f |= _PAGE_WRENABLE; 176 else 177 /* On the MicroBlaze, no user access 178 forces R/W kernel access */ 179 f |= _PAGE_USER; 180 map_page(v, p, f); 181 v += PAGE_SIZE; 182 p += PAGE_SIZE; 183 } 184 } 185 186 /* is x a power of 2? */ 187 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0)) 188 189 /* Scan the real Linux page tables and return a PTE pointer for 190 * a virtual address in a context. 191 * Returns true (1) if PTE was found, zero otherwise. The pointer to 192 * the PTE pointer is unmodified if PTE is not found. 193 */ 194 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep) 195 { 196 pgd_t *pgd; 197 p4d_t *p4d; 198 pud_t *pud; 199 pmd_t *pmd; 200 pte_t *pte; 201 int retval = 0; 202 203 pgd = pgd_offset(mm, addr & PAGE_MASK); 204 if (pgd) { 205 p4d = p4d_offset(pgd, addr & PAGE_MASK); 206 pud = pud_offset(p4d, addr & PAGE_MASK); 207 pmd = pmd_offset(pud, addr & PAGE_MASK); 208 if (pmd_present(*pmd)) { 209 pte = pte_offset_kernel(pmd, addr & PAGE_MASK); 210 if (pte) { 211 retval = 1; 212 *ptep = pte; 213 } 214 } 215 } 216 return retval; 217 } 218 219 /* Find physical address for this virtual address. Normally used by 220 * I/O functions, but anyone can call it. 221 */ 222 unsigned long iopa(unsigned long addr) 223 { 224 unsigned long pa; 225 226 pte_t *pte; 227 struct mm_struct *mm; 228 229 /* Allow mapping of user addresses (within the thread) 230 * for DMA if necessary. 231 */ 232 if (addr < TASK_SIZE) 233 mm = current->mm; 234 else 235 mm = &init_mm; 236 237 pa = 0; 238 if (get_pteptr(mm, addr, &pte)) 239 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK); 240 241 return pa; 242 } 243 244 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm) 245 { 246 if (mem_init_done) 247 return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 248 else 249 return memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE, 250 MEMBLOCK_LOW_LIMIT, 251 memory_start + kernel_tlb, 252 NUMA_NO_NODE); 253 } 254 255 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) 256 { 257 unsigned long address = __fix_to_virt(idx); 258 259 if (idx >= __end_of_fixed_addresses) 260 BUG(); 261 262 map_page(address, phys, pgprot_val(flags)); 263 } 264