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 41 #define flush_HPTE(X, va, pg) _tlbie(va) 42 43 unsigned long ioremap_base; 44 unsigned long ioremap_bot; 45 46 /* The maximum lowmem defaults to 768Mb, but this can be configured to 47 * another value. 48 */ 49 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 50 51 #ifndef CONFIG_SMP 52 struct pgtable_cache_struct quicklists; 53 #endif 54 55 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, 56 unsigned long flags) 57 { 58 unsigned long v, i; 59 phys_addr_t p; 60 int err; 61 62 /* 63 * Choose an address to map it to. 64 * Once the vmalloc system is running, we use it. 65 * Before then, we use space going down from ioremap_base 66 * (ioremap_bot records where we're up to). 67 */ 68 p = addr & PAGE_MASK; 69 size = PAGE_ALIGN(addr + size) - p; 70 71 /* 72 * Don't allow anybody to remap normal RAM that we're using. 73 * mem_init() sets high_memory so only do the check after that. 74 * 75 * However, allow remap of rootfs: TBD 76 */ 77 if (mem_init_done && 78 p >= memory_start && p < virt_to_phys(high_memory) && 79 !(p >= virt_to_phys((unsigned long)&__bss_stop) && 80 p < virt_to_phys((unsigned long)__bss_stop))) { 81 printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT 82 " is RAM lr %p\n", (unsigned long)p, 83 __builtin_return_address(0)); 84 return NULL; 85 } 86 87 if (size == 0) 88 return NULL; 89 90 /* 91 * Is it already mapped? If the whole area is mapped then we're 92 * done, otherwise remap it since we want to keep the virt addrs for 93 * each request contiguous. 94 * 95 * We make the assumption here that if the bottom and top 96 * of the range we want are mapped then it's mapped to the 97 * same virt address (and this is contiguous). 98 * -- Cort 99 */ 100 101 if (mem_init_done) { 102 struct vm_struct *area; 103 area = get_vm_area(size, VM_IOREMAP); 104 if (area == NULL) 105 return NULL; 106 v = VMALLOC_VMADDR(area->addr); 107 } else { 108 v = (ioremap_bot -= size); 109 } 110 111 if ((flags & _PAGE_PRESENT) == 0) 112 flags |= _PAGE_KERNEL; 113 if (flags & _PAGE_NO_CACHE) 114 flags |= _PAGE_GUARDED; 115 116 err = 0; 117 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 118 err = map_page(v + i, p + i, flags); 119 if (err) { 120 if (mem_init_done) 121 vfree((void *)v); 122 return NULL; 123 } 124 125 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 126 } 127 128 void __iomem *ioremap(phys_addr_t addr, unsigned long size) 129 { 130 return __ioremap(addr, size, _PAGE_NO_CACHE); 131 } 132 EXPORT_SYMBOL(ioremap); 133 134 void iounmap(void *addr) 135 { 136 if (addr > high_memory && (unsigned long) addr < ioremap_bot) 137 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 138 } 139 EXPORT_SYMBOL(iounmap); 140 141 142 int map_page(unsigned long va, phys_addr_t pa, int flags) 143 { 144 pmd_t *pd; 145 pte_t *pg; 146 int err = -ENOMEM; 147 /* spin_lock(&init_mm.page_table_lock); */ 148 /* Use upper 10 bits of VA to index the first level map */ 149 pd = pmd_offset(pgd_offset_k(va), va); 150 /* Use middle 10 bits of VA to index the second-level map */ 151 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */ 152 /* pg = pte_alloc_kernel(&init_mm, pd, va); */ 153 154 if (pg != NULL) { 155 err = 0; 156 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 157 __pgprot(flags))); 158 if (mem_init_done) 159 flush_HPTE(0, va, pmd_val(*pd)); 160 /* flush_HPTE(0, va, pg); */ 161 162 } 163 /* spin_unlock(&init_mm.page_table_lock); */ 164 return err; 165 } 166 167 void __init adjust_total_lowmem(void) 168 { 169 /* TBD */ 170 #if 0 171 unsigned long max_low_mem = MAX_LOW_MEM; 172 173 if (total_lowmem > max_low_mem) { 174 total_lowmem = max_low_mem; 175 #ifndef CONFIG_HIGHMEM 176 printk(KERN_INFO "Warning, memory limited to %ld Mb, use " 177 "CONFIG_HIGHMEM to reach %ld Mb\n", 178 max_low_mem >> 20, total_memory >> 20); 179 total_memory = total_lowmem; 180 #endif /* CONFIG_HIGHMEM */ 181 } 182 #endif 183 } 184 185 static void show_tmem(unsigned long tmem) 186 { 187 volatile unsigned long a; 188 a = a + tmem; 189 } 190 191 /* 192 * Map in all of physical memory starting at CONFIG_KERNEL_START. 193 */ 194 void __init mapin_ram(void) 195 { 196 unsigned long v, p, s, f; 197 198 v = CONFIG_KERNEL_START; 199 p = memory_start; 200 show_tmem(memory_size); 201 for (s = 0; s < memory_size; s += PAGE_SIZE) { 202 f = _PAGE_PRESENT | _PAGE_ACCESSED | 203 _PAGE_SHARED | _PAGE_HWEXEC; 204 if ((char *) v < _stext || (char *) v >= _etext) 205 f |= _PAGE_WRENABLE; 206 else 207 /* On the MicroBlaze, no user access 208 forces R/W kernel access */ 209 f |= _PAGE_USER; 210 map_page(v, p, f); 211 v += PAGE_SIZE; 212 p += PAGE_SIZE; 213 } 214 } 215 216 /* is x a power of 2? */ 217 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0)) 218 219 /* 220 * Set up a mapping for a block of I/O. 221 * virt, phys, size must all be page-aligned. 222 * This should only be called before ioremap is called. 223 */ 224 void __init io_block_mapping(unsigned long virt, phys_addr_t phys, 225 unsigned int size, int flags) 226 { 227 int i; 228 229 if (virt > CONFIG_KERNEL_START && virt < ioremap_bot) 230 ioremap_bot = ioremap_base = virt; 231 232 /* Put it in the page tables. */ 233 for (i = 0; i < size; i += PAGE_SIZE) 234 map_page(virt + i, phys + i, flags); 235 } 236 237 /* Scan the real Linux page tables and return a PTE pointer for 238 * a virtual address in a context. 239 * Returns true (1) if PTE was found, zero otherwise. The pointer to 240 * the PTE pointer is unmodified if PTE is not found. 241 */ 242 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep) 243 { 244 pgd_t *pgd; 245 pmd_t *pmd; 246 pte_t *pte; 247 int retval = 0; 248 249 pgd = pgd_offset(mm, addr & PAGE_MASK); 250 if (pgd) { 251 pmd = pmd_offset(pgd, addr & PAGE_MASK); 252 if (pmd_present(*pmd)) { 253 pte = pte_offset_kernel(pmd, addr & PAGE_MASK); 254 if (pte) { 255 retval = 1; 256 *ptep = pte; 257 } 258 } 259 } 260 return retval; 261 } 262 263 /* Find physical address for this virtual address. Normally used by 264 * I/O functions, but anyone can call it. 265 */ 266 unsigned long iopa(unsigned long addr) 267 { 268 unsigned long pa; 269 270 pte_t *pte; 271 struct mm_struct *mm; 272 273 /* Allow mapping of user addresses (within the thread) 274 * for DMA if necessary. 275 */ 276 if (addr < TASK_SIZE) 277 mm = current->mm; 278 else 279 mm = &init_mm; 280 281 pa = 0; 282 if (get_pteptr(mm, addr, &pte)) 283 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK); 284 285 return pa; 286 } 287