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
__ioremap(phys_addr_t addr,unsigned long size,unsigned long flags)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
ioremap(phys_addr_t addr,unsigned long size)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
iounmap(volatile void __iomem * addr)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
map_page(unsigned long va,phys_addr_t pa,int flags)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 */
mapin_ram(void)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 */
get_pteptr(struct mm_struct * mm,unsigned long addr,pte_t ** ptep)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 */
iopa(unsigned long addr)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
pte_alloc_one_kernel(struct mm_struct * mm)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
__set_fixmap(enum fixed_addresses idx,phys_addr_t phys,pgprot_t flags)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