1 /*
2 * Copyright IBM Corp. 2006
3 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
4 */
5
6 #include <linux/bootmem.h>
7 #include <linux/pfn.h>
8 #include <linux/mm.h>
9 #include <linux/module.h>
10 #include <linux/list.h>
11 #include <linux/hugetlb.h>
12 #include <linux/slab.h>
13 #include <linux/memblock.h>
14 #include <asm/cacheflush.h>
15 #include <asm/pgalloc.h>
16 #include <asm/pgtable.h>
17 #include <asm/setup.h>
18 #include <asm/tlbflush.h>
19 #include <asm/sections.h>
20
21 static DEFINE_MUTEX(vmem_mutex);
22
23 struct memory_segment {
24 struct list_head list;
25 unsigned long start;
26 unsigned long size;
27 };
28
29 static LIST_HEAD(mem_segs);
30
vmem_alloc_pages(unsigned int order)31 static void __ref *vmem_alloc_pages(unsigned int order)
32 {
33 unsigned long size = PAGE_SIZE << order;
34
35 if (slab_is_available())
36 return (void *)__get_free_pages(GFP_KERNEL, order);
37 return alloc_bootmem_align(size, size);
38 }
39
vmem_pud_alloc(void)40 static inline pud_t *vmem_pud_alloc(void)
41 {
42 pud_t *pud = NULL;
43
44 pud = vmem_alloc_pages(2);
45 if (!pud)
46 return NULL;
47 clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
48 return pud;
49 }
50
vmem_pmd_alloc(void)51 pmd_t *vmem_pmd_alloc(void)
52 {
53 pmd_t *pmd = NULL;
54
55 pmd = vmem_alloc_pages(2);
56 if (!pmd)
57 return NULL;
58 clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
59 return pmd;
60 }
61
vmem_pte_alloc(void)62 pte_t __ref *vmem_pte_alloc(void)
63 {
64 pte_t *pte;
65
66 if (slab_is_available())
67 pte = (pte_t *) page_table_alloc(&init_mm);
68 else
69 pte = alloc_bootmem_align(PTRS_PER_PTE * sizeof(pte_t),
70 PTRS_PER_PTE * sizeof(pte_t));
71 if (!pte)
72 return NULL;
73 clear_table((unsigned long *) pte, _PAGE_INVALID,
74 PTRS_PER_PTE * sizeof(pte_t));
75 return pte;
76 }
77
78 /*
79 * Add a physical memory range to the 1:1 mapping.
80 */
vmem_add_mem(unsigned long start,unsigned long size)81 static int vmem_add_mem(unsigned long start, unsigned long size)
82 {
83 unsigned long pages4k, pages1m, pages2g;
84 unsigned long end = start + size;
85 unsigned long address = start;
86 pgd_t *pg_dir;
87 pud_t *pu_dir;
88 pmd_t *pm_dir;
89 pte_t *pt_dir;
90 int ret = -ENOMEM;
91
92 pages4k = pages1m = pages2g = 0;
93 while (address < end) {
94 pg_dir = pgd_offset_k(address);
95 if (pgd_none(*pg_dir)) {
96 pu_dir = vmem_pud_alloc();
97 if (!pu_dir)
98 goto out;
99 pgd_populate(&init_mm, pg_dir, pu_dir);
100 }
101 pu_dir = pud_offset(pg_dir, address);
102 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
103 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&
104 !debug_pagealloc_enabled()) {
105 pud_val(*pu_dir) = address | pgprot_val(REGION3_KERNEL);
106 address += PUD_SIZE;
107 pages2g++;
108 continue;
109 }
110 if (pud_none(*pu_dir)) {
111 pm_dir = vmem_pmd_alloc();
112 if (!pm_dir)
113 goto out;
114 pud_populate(&init_mm, pu_dir, pm_dir);
115 }
116 pm_dir = pmd_offset(pu_dir, address);
117 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
118 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&
119 !debug_pagealloc_enabled()) {
120 pmd_val(*pm_dir) = address | pgprot_val(SEGMENT_KERNEL);
121 address += PMD_SIZE;
122 pages1m++;
123 continue;
124 }
125 if (pmd_none(*pm_dir)) {
126 pt_dir = vmem_pte_alloc();
127 if (!pt_dir)
128 goto out;
129 pmd_populate(&init_mm, pm_dir, pt_dir);
130 }
131
132 pt_dir = pte_offset_kernel(pm_dir, address);
133 pte_val(*pt_dir) = address | pgprot_val(PAGE_KERNEL);
134 address += PAGE_SIZE;
135 pages4k++;
136 }
137 ret = 0;
138 out:
139 update_page_count(PG_DIRECT_MAP_4K, pages4k);
140 update_page_count(PG_DIRECT_MAP_1M, pages1m);
141 update_page_count(PG_DIRECT_MAP_2G, pages2g);
142 return ret;
143 }
144
145 /*
146 * Remove a physical memory range from the 1:1 mapping.
147 * Currently only invalidates page table entries.
148 */
vmem_remove_range(unsigned long start,unsigned long size)149 static void vmem_remove_range(unsigned long start, unsigned long size)
150 {
151 unsigned long pages4k, pages1m, pages2g;
152 unsigned long end = start + size;
153 unsigned long address = start;
154 pgd_t *pg_dir;
155 pud_t *pu_dir;
156 pmd_t *pm_dir;
157 pte_t *pt_dir;
158
159 pages4k = pages1m = pages2g = 0;
160 while (address < end) {
161 pg_dir = pgd_offset_k(address);
162 if (pgd_none(*pg_dir)) {
163 address += PGDIR_SIZE;
164 continue;
165 }
166 pu_dir = pud_offset(pg_dir, address);
167 if (pud_none(*pu_dir)) {
168 address += PUD_SIZE;
169 continue;
170 }
171 if (pud_large(*pu_dir)) {
172 pud_clear(pu_dir);
173 address += PUD_SIZE;
174 pages2g++;
175 continue;
176 }
177 pm_dir = pmd_offset(pu_dir, address);
178 if (pmd_none(*pm_dir)) {
179 address += PMD_SIZE;
180 continue;
181 }
182 if (pmd_large(*pm_dir)) {
183 pmd_clear(pm_dir);
184 address += PMD_SIZE;
185 pages1m++;
186 continue;
187 }
188 pt_dir = pte_offset_kernel(pm_dir, address);
189 pte_clear(&init_mm, address, pt_dir);
190 address += PAGE_SIZE;
191 pages4k++;
192 }
193 flush_tlb_kernel_range(start, end);
194 update_page_count(PG_DIRECT_MAP_4K, -pages4k);
195 update_page_count(PG_DIRECT_MAP_1M, -pages1m);
196 update_page_count(PG_DIRECT_MAP_2G, -pages2g);
197 }
198
199 /*
200 * Add a backed mem_map array to the virtual mem_map array.
201 */
vmemmap_populate(unsigned long start,unsigned long end,int node)202 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
203 {
204 unsigned long address = start;
205 pgd_t *pg_dir;
206 pud_t *pu_dir;
207 pmd_t *pm_dir;
208 pte_t *pt_dir;
209 int ret = -ENOMEM;
210
211 for (address = start; address < end;) {
212 pg_dir = pgd_offset_k(address);
213 if (pgd_none(*pg_dir)) {
214 pu_dir = vmem_pud_alloc();
215 if (!pu_dir)
216 goto out;
217 pgd_populate(&init_mm, pg_dir, pu_dir);
218 }
219
220 pu_dir = pud_offset(pg_dir, address);
221 if (pud_none(*pu_dir)) {
222 pm_dir = vmem_pmd_alloc();
223 if (!pm_dir)
224 goto out;
225 pud_populate(&init_mm, pu_dir, pm_dir);
226 }
227
228 pm_dir = pmd_offset(pu_dir, address);
229 if (pmd_none(*pm_dir)) {
230 /* Use 1MB frames for vmemmap if available. We always
231 * use large frames even if they are only partially
232 * used.
233 * Otherwise we would have also page tables since
234 * vmemmap_populate gets called for each section
235 * separately. */
236 if (MACHINE_HAS_EDAT1) {
237 void *new_page;
238
239 new_page = vmemmap_alloc_block(PMD_SIZE, node);
240 if (!new_page)
241 goto out;
242 pmd_val(*pm_dir) = __pa(new_page) |
243 _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE;
244 address = (address + PMD_SIZE) & PMD_MASK;
245 continue;
246 }
247 pt_dir = vmem_pte_alloc();
248 if (!pt_dir)
249 goto out;
250 pmd_populate(&init_mm, pm_dir, pt_dir);
251 } else if (pmd_large(*pm_dir)) {
252 address = (address + PMD_SIZE) & PMD_MASK;
253 continue;
254 }
255
256 pt_dir = pte_offset_kernel(pm_dir, address);
257 if (pte_none(*pt_dir)) {
258 void *new_page;
259
260 new_page = vmemmap_alloc_block(PAGE_SIZE, node);
261 if (!new_page)
262 goto out;
263 pte_val(*pt_dir) =
264 __pa(new_page) | pgprot_val(PAGE_KERNEL);
265 }
266 address += PAGE_SIZE;
267 }
268 ret = 0;
269 out:
270 return ret;
271 }
272
vmemmap_free(unsigned long start,unsigned long end)273 void vmemmap_free(unsigned long start, unsigned long end)
274 {
275 }
276
277 /*
278 * Add memory segment to the segment list if it doesn't overlap with
279 * an already present segment.
280 */
insert_memory_segment(struct memory_segment * seg)281 static int insert_memory_segment(struct memory_segment *seg)
282 {
283 struct memory_segment *tmp;
284
285 if (seg->start + seg->size > VMEM_MAX_PHYS ||
286 seg->start + seg->size < seg->start)
287 return -ERANGE;
288
289 list_for_each_entry(tmp, &mem_segs, list) {
290 if (seg->start >= tmp->start + tmp->size)
291 continue;
292 if (seg->start + seg->size <= tmp->start)
293 continue;
294 return -ENOSPC;
295 }
296 list_add(&seg->list, &mem_segs);
297 return 0;
298 }
299
300 /*
301 * Remove memory segment from the segment list.
302 */
remove_memory_segment(struct memory_segment * seg)303 static void remove_memory_segment(struct memory_segment *seg)
304 {
305 list_del(&seg->list);
306 }
307
__remove_shared_memory(struct memory_segment * seg)308 static void __remove_shared_memory(struct memory_segment *seg)
309 {
310 remove_memory_segment(seg);
311 vmem_remove_range(seg->start, seg->size);
312 }
313
vmem_remove_mapping(unsigned long start,unsigned long size)314 int vmem_remove_mapping(unsigned long start, unsigned long size)
315 {
316 struct memory_segment *seg;
317 int ret;
318
319 mutex_lock(&vmem_mutex);
320
321 ret = -ENOENT;
322 list_for_each_entry(seg, &mem_segs, list) {
323 if (seg->start == start && seg->size == size)
324 break;
325 }
326
327 if (seg->start != start || seg->size != size)
328 goto out;
329
330 ret = 0;
331 __remove_shared_memory(seg);
332 kfree(seg);
333 out:
334 mutex_unlock(&vmem_mutex);
335 return ret;
336 }
337
vmem_add_mapping(unsigned long start,unsigned long size)338 int vmem_add_mapping(unsigned long start, unsigned long size)
339 {
340 struct memory_segment *seg;
341 int ret;
342
343 mutex_lock(&vmem_mutex);
344 ret = -ENOMEM;
345 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
346 if (!seg)
347 goto out;
348 seg->start = start;
349 seg->size = size;
350
351 ret = insert_memory_segment(seg);
352 if (ret)
353 goto out_free;
354
355 ret = vmem_add_mem(start, size);
356 if (ret)
357 goto out_remove;
358 goto out;
359
360 out_remove:
361 __remove_shared_memory(seg);
362 out_free:
363 kfree(seg);
364 out:
365 mutex_unlock(&vmem_mutex);
366 return ret;
367 }
368
369 /*
370 * map whole physical memory to virtual memory (identity mapping)
371 * we reserve enough space in the vmalloc area for vmemmap to hotplug
372 * additional memory segments.
373 */
vmem_map_init(void)374 void __init vmem_map_init(void)
375 {
376 unsigned long size = _eshared - _stext;
377 struct memblock_region *reg;
378
379 for_each_memblock(memory, reg)
380 vmem_add_mem(reg->base, reg->size);
381 set_memory_ro((unsigned long)_stext, size >> PAGE_SHIFT);
382 pr_info("Write protected kernel read-only data: %luk\n", size >> 10);
383 }
384
385 /*
386 * Convert memblock.memory to a memory segment list so there is a single
387 * list that contains all memory segments.
388 */
vmem_convert_memory_chunk(void)389 static int __init vmem_convert_memory_chunk(void)
390 {
391 struct memblock_region *reg;
392 struct memory_segment *seg;
393
394 mutex_lock(&vmem_mutex);
395 for_each_memblock(memory, reg) {
396 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
397 if (!seg)
398 panic("Out of memory...\n");
399 seg->start = reg->base;
400 seg->size = reg->size;
401 insert_memory_segment(seg);
402 }
403 mutex_unlock(&vmem_mutex);
404 return 0;
405 }
406
407 core_initcall(vmem_convert_memory_chunk);
408