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