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