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
37 #include <asm/pgalloc.h>
38 #include <linux/io.h>
39 #include <asm/mmu.h>
40 #include <asm/sections.h>
41 #include <asm/fixmap.h>
42
43 unsigned long ioremap_base;
44 unsigned long ioremap_bot;
45 EXPORT_SYMBOL(ioremap_bot);
46
__ioremap(phys_addr_t addr,unsigned long size,unsigned long flags)47 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
48 unsigned long flags)
49 {
50 unsigned long v, i;
51 phys_addr_t p;
52 int err;
53
54 /*
55 * Choose an address to map it to.
56 * Once the vmalloc system is running, we use it.
57 * Before then, we use space going down from ioremap_base
58 * (ioremap_bot records where we're up to).
59 */
60 p = addr & PAGE_MASK;
61 size = PAGE_ALIGN(addr + size) - p;
62
63 /*
64 * Don't allow anybody to remap normal RAM that we're using.
65 * mem_init() sets high_memory so only do the check after that.
66 *
67 * However, allow remap of rootfs: TBD
68 */
69
70 if (mem_init_done &&
71 p >= memory_start && p < virt_to_phys(high_memory) &&
72 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) &&
73 p < __virt_to_phys((phys_addr_t)__bss_stop))) {
74 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %ps\n",
75 (unsigned long)p, __builtin_return_address(0));
76 return NULL;
77 }
78
79 if (size == 0)
80 return NULL;
81
82 /*
83 * Is it already mapped? If the whole area is mapped then we're
84 * done, otherwise remap it since we want to keep the virt addrs for
85 * each request contiguous.
86 *
87 * We make the assumption here that if the bottom and top
88 * of the range we want are mapped then it's mapped to the
89 * same virt address (and this is contiguous).
90 * -- Cort
91 */
92
93 if (mem_init_done) {
94 struct vm_struct *area;
95 area = get_vm_area(size, VM_IOREMAP);
96 if (area == NULL)
97 return NULL;
98 v = (unsigned long) area->addr;
99 } else {
100 v = (ioremap_bot -= size);
101 }
102
103 if ((flags & _PAGE_PRESENT) == 0)
104 flags |= _PAGE_KERNEL;
105 if (flags & _PAGE_NO_CACHE)
106 flags |= _PAGE_GUARDED;
107
108 err = 0;
109 for (i = 0; i < size && err == 0; i += PAGE_SIZE)
110 err = map_page(v + i, p + i, flags);
111 if (err) {
112 if (mem_init_done)
113 vfree((void *)v);
114 return NULL;
115 }
116
117 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
118 }
119
ioremap(phys_addr_t addr,unsigned long size)120 void __iomem *ioremap(phys_addr_t addr, unsigned long size)
121 {
122 return __ioremap(addr, size, _PAGE_NO_CACHE);
123 }
124 EXPORT_SYMBOL(ioremap);
125
iounmap(volatile void __iomem * addr)126 void iounmap(volatile void __iomem *addr)
127 {
128 if ((__force void *)addr > high_memory &&
129 (unsigned long) addr < ioremap_bot)
130 vfree((void *) (PAGE_MASK & (unsigned long) addr));
131 }
132 EXPORT_SYMBOL(iounmap);
133
134
map_page(unsigned long va,phys_addr_t pa,int flags)135 int map_page(unsigned long va, phys_addr_t pa, int flags)
136 {
137 p4d_t *p4d;
138 pud_t *pud;
139 pmd_t *pd;
140 pte_t *pg;
141 int err = -ENOMEM;
142
143 /* Use upper 10 bits of VA to index the first level map */
144 p4d = p4d_offset(pgd_offset_k(va), va);
145 pud = pud_offset(p4d, va);
146 pd = pmd_offset(pud, va);
147 /* Use middle 10 bits of VA to index the second-level map */
148 pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
149 /* pg = pte_alloc_kernel(&init_mm, pd, va); */
150
151 if (pg != NULL) {
152 err = 0;
153 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
154 __pgprot(flags)));
155 if (unlikely(mem_init_done))
156 _tlbie(va);
157 }
158 return err;
159 }
160
161 /*
162 * Map in all of physical memory starting at CONFIG_KERNEL_START.
163 */
mapin_ram(void)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 */
get_pteptr(struct mm_struct * mm,unsigned long addr,pte_t ** ptep)193 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
194 {
195 pgd_t *pgd;
196 p4d_t *p4d;
197 pud_t *pud;
198 pmd_t *pmd;
199 pte_t *pte;
200 int retval = 0;
201
202 pgd = pgd_offset(mm, addr & PAGE_MASK);
203 if (pgd) {
204 p4d = p4d_offset(pgd, addr & PAGE_MASK);
205 pud = pud_offset(p4d, addr & PAGE_MASK);
206 pmd = pmd_offset(pud, addr & PAGE_MASK);
207 if (pmd_present(*pmd)) {
208 pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
209 if (pte) {
210 retval = 1;
211 *ptep = pte;
212 }
213 }
214 }
215 return retval;
216 }
217
218 /* Find physical address for this virtual address. Normally used by
219 * I/O functions, but anyone can call it.
220 */
iopa(unsigned long addr)221 unsigned long iopa(unsigned long addr)
222 {
223 unsigned long pa;
224
225 pte_t *pte;
226 struct mm_struct *mm;
227
228 /* Allow mapping of user addresses (within the thread)
229 * for DMA if necessary.
230 */
231 if (addr < TASK_SIZE)
232 mm = current->mm;
233 else
234 mm = &init_mm;
235
236 pa = 0;
237 if (get_pteptr(mm, addr, &pte))
238 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
239
240 return pa;
241 }
242
pte_alloc_one_kernel(struct mm_struct * mm)243 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
244 {
245 pte_t *pte;
246 if (mem_init_done) {
247 pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
248 } else {
249 pte = (pte_t *)early_get_page();
250 if (pte)
251 clear_page(pte);
252 }
253 return pte;
254 }
255
__set_fixmap(enum fixed_addresses idx,phys_addr_t phys,pgprot_t flags)256 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
257 {
258 unsigned long address = __fix_to_virt(idx);
259
260 if (idx >= __end_of_fixed_addresses)
261 BUG();
262
263 map_page(address, phys, pgprot_val(flags));
264 }
265