1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2006
4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
5 */
6
7 #include <linux/memblock.h>
8 #include <linux/pfn.h>
9 #include <linux/mm.h>
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/hugetlb.h>
13 #include <linux/slab.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 #include <asm/set_memory.h>
21
22 static DEFINE_MUTEX(vmem_mutex);
23
24 struct memory_segment {
25 struct list_head list;
26 unsigned long start;
27 unsigned long size;
28 };
29
30 static LIST_HEAD(mem_segs);
31
vmem_alloc_pages(unsigned int order)32 static void __ref *vmem_alloc_pages(unsigned int order)
33 {
34 unsigned long size = PAGE_SIZE << order;
35
36 if (slab_is_available())
37 return (void *)__get_free_pages(GFP_KERNEL, order);
38 return (void *) memblock_phys_alloc(size, size);
39 }
40
vmem_crst_alloc(unsigned long val)41 void *vmem_crst_alloc(unsigned long val)
42 {
43 unsigned long *table;
44
45 table = vmem_alloc_pages(CRST_ALLOC_ORDER);
46 if (table)
47 crst_table_init(table, val);
48 return table;
49 }
50
vmem_pte_alloc(void)51 pte_t __ref *vmem_pte_alloc(void)
52 {
53 unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
54 pte_t *pte;
55
56 if (slab_is_available())
57 pte = (pte_t *) page_table_alloc(&init_mm);
58 else
59 pte = (pte_t *) memblock_phys_alloc(size, size);
60 if (!pte)
61 return NULL;
62 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
63 return pte;
64 }
65
66 /*
67 * Add a physical memory range to the 1:1 mapping.
68 */
vmem_add_mem(unsigned long start,unsigned long size)69 static int vmem_add_mem(unsigned long start, unsigned long size)
70 {
71 unsigned long pgt_prot, sgt_prot, r3_prot;
72 unsigned long pages4k, pages1m, pages2g;
73 unsigned long end = start + size;
74 unsigned long address = start;
75 pgd_t *pg_dir;
76 p4d_t *p4_dir;
77 pud_t *pu_dir;
78 pmd_t *pm_dir;
79 pte_t *pt_dir;
80 int ret = -ENOMEM;
81
82 pgt_prot = pgprot_val(PAGE_KERNEL);
83 sgt_prot = pgprot_val(SEGMENT_KERNEL);
84 r3_prot = pgprot_val(REGION3_KERNEL);
85 if (!MACHINE_HAS_NX) {
86 pgt_prot &= ~_PAGE_NOEXEC;
87 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
88 r3_prot &= ~_REGION_ENTRY_NOEXEC;
89 }
90 pages4k = pages1m = pages2g = 0;
91 while (address < end) {
92 pg_dir = pgd_offset_k(address);
93 if (pgd_none(*pg_dir)) {
94 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
95 if (!p4_dir)
96 goto out;
97 pgd_populate(&init_mm, pg_dir, p4_dir);
98 }
99 p4_dir = p4d_offset(pg_dir, address);
100 if (p4d_none(*p4_dir)) {
101 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
102 if (!pu_dir)
103 goto out;
104 p4d_populate(&init_mm, p4_dir, pu_dir);
105 }
106 pu_dir = pud_offset(p4_dir, address);
107 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
108 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&
109 !debug_pagealloc_enabled()) {
110 pud_val(*pu_dir) = address | r3_prot;
111 address += PUD_SIZE;
112 pages2g++;
113 continue;
114 }
115 if (pud_none(*pu_dir)) {
116 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
117 if (!pm_dir)
118 goto out;
119 pud_populate(&init_mm, pu_dir, pm_dir);
120 }
121 pm_dir = pmd_offset(pu_dir, address);
122 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
123 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&
124 !debug_pagealloc_enabled()) {
125 pmd_val(*pm_dir) = address | sgt_prot;
126 address += PMD_SIZE;
127 pages1m++;
128 continue;
129 }
130 if (pmd_none(*pm_dir)) {
131 pt_dir = vmem_pte_alloc();
132 if (!pt_dir)
133 goto out;
134 pmd_populate(&init_mm, pm_dir, pt_dir);
135 }
136
137 pt_dir = pte_offset_kernel(pm_dir, address);
138 pte_val(*pt_dir) = address | pgt_prot;
139 address += PAGE_SIZE;
140 pages4k++;
141 }
142 ret = 0;
143 out:
144 update_page_count(PG_DIRECT_MAP_4K, pages4k);
145 update_page_count(PG_DIRECT_MAP_1M, pages1m);
146 update_page_count(PG_DIRECT_MAP_2G, pages2g);
147 return ret;
148 }
149
150 /*
151 * Remove a physical memory range from the 1:1 mapping.
152 * Currently only invalidates page table entries.
153 */
vmem_remove_range(unsigned long start,unsigned long size)154 static void vmem_remove_range(unsigned long start, unsigned long size)
155 {
156 unsigned long pages4k, pages1m, pages2g;
157 unsigned long end = start + size;
158 unsigned long address = start;
159 pgd_t *pg_dir;
160 p4d_t *p4_dir;
161 pud_t *pu_dir;
162 pmd_t *pm_dir;
163 pte_t *pt_dir;
164
165 pages4k = pages1m = pages2g = 0;
166 while (address < end) {
167 pg_dir = pgd_offset_k(address);
168 if (pgd_none(*pg_dir)) {
169 address += PGDIR_SIZE;
170 continue;
171 }
172 p4_dir = p4d_offset(pg_dir, address);
173 if (p4d_none(*p4_dir)) {
174 address += P4D_SIZE;
175 continue;
176 }
177 pu_dir = pud_offset(p4_dir, address);
178 if (pud_none(*pu_dir)) {
179 address += PUD_SIZE;
180 continue;
181 }
182 if (pud_large(*pu_dir)) {
183 pud_clear(pu_dir);
184 address += PUD_SIZE;
185 pages2g++;
186 continue;
187 }
188 pm_dir = pmd_offset(pu_dir, address);
189 if (pmd_none(*pm_dir)) {
190 address += PMD_SIZE;
191 continue;
192 }
193 if (pmd_large(*pm_dir)) {
194 pmd_clear(pm_dir);
195 address += PMD_SIZE;
196 pages1m++;
197 continue;
198 }
199 pt_dir = pte_offset_kernel(pm_dir, address);
200 pte_clear(&init_mm, address, pt_dir);
201 address += PAGE_SIZE;
202 pages4k++;
203 }
204 flush_tlb_kernel_range(start, end);
205 update_page_count(PG_DIRECT_MAP_4K, -pages4k);
206 update_page_count(PG_DIRECT_MAP_1M, -pages1m);
207 update_page_count(PG_DIRECT_MAP_2G, -pages2g);
208 }
209
210 /*
211 * Add a backed mem_map array to the virtual mem_map array.
212 */
vmemmap_populate(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)213 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
214 struct vmem_altmap *altmap)
215 {
216 unsigned long pgt_prot, sgt_prot;
217 unsigned long address = start;
218 pgd_t *pg_dir;
219 p4d_t *p4_dir;
220 pud_t *pu_dir;
221 pmd_t *pm_dir;
222 pte_t *pt_dir;
223 int ret = -ENOMEM;
224
225 pgt_prot = pgprot_val(PAGE_KERNEL);
226 sgt_prot = pgprot_val(SEGMENT_KERNEL);
227 if (!MACHINE_HAS_NX) {
228 pgt_prot &= ~_PAGE_NOEXEC;
229 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
230 }
231 for (address = start; address < end;) {
232 pg_dir = pgd_offset_k(address);
233 if (pgd_none(*pg_dir)) {
234 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
235 if (!p4_dir)
236 goto out;
237 pgd_populate(&init_mm, pg_dir, p4_dir);
238 }
239
240 p4_dir = p4d_offset(pg_dir, address);
241 if (p4d_none(*p4_dir)) {
242 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
243 if (!pu_dir)
244 goto out;
245 p4d_populate(&init_mm, p4_dir, pu_dir);
246 }
247
248 pu_dir = pud_offset(p4_dir, address);
249 if (pud_none(*pu_dir)) {
250 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
251 if (!pm_dir)
252 goto out;
253 pud_populate(&init_mm, pu_dir, pm_dir);
254 }
255
256 pm_dir = pmd_offset(pu_dir, address);
257 if (pmd_none(*pm_dir)) {
258 /* Use 1MB frames for vmemmap if available. We always
259 * use large frames even if they are only partially
260 * used.
261 * Otherwise we would have also page tables since
262 * vmemmap_populate gets called for each section
263 * separately. */
264 if (MACHINE_HAS_EDAT1) {
265 void *new_page;
266
267 new_page = vmemmap_alloc_block(PMD_SIZE, node);
268 if (!new_page)
269 goto out;
270 pmd_val(*pm_dir) = __pa(new_page) | sgt_prot;
271 address = (address + PMD_SIZE) & PMD_MASK;
272 continue;
273 }
274 pt_dir = vmem_pte_alloc();
275 if (!pt_dir)
276 goto out;
277 pmd_populate(&init_mm, pm_dir, pt_dir);
278 } else if (pmd_large(*pm_dir)) {
279 address = (address + PMD_SIZE) & PMD_MASK;
280 continue;
281 }
282
283 pt_dir = pte_offset_kernel(pm_dir, address);
284 if (pte_none(*pt_dir)) {
285 void *new_page;
286
287 new_page = vmemmap_alloc_block(PAGE_SIZE, node);
288 if (!new_page)
289 goto out;
290 pte_val(*pt_dir) = __pa(new_page) | pgt_prot;
291 }
292 address += PAGE_SIZE;
293 }
294 ret = 0;
295 out:
296 return ret;
297 }
298
vmemmap_free(unsigned long start,unsigned long end,struct vmem_altmap * altmap)299 void vmemmap_free(unsigned long start, unsigned long end,
300 struct vmem_altmap *altmap)
301 {
302 }
303
304 /*
305 * Add memory segment to the segment list if it doesn't overlap with
306 * an already present segment.
307 */
insert_memory_segment(struct memory_segment * seg)308 static int insert_memory_segment(struct memory_segment *seg)
309 {
310 struct memory_segment *tmp;
311
312 if (seg->start + seg->size > VMEM_MAX_PHYS ||
313 seg->start + seg->size < seg->start)
314 return -ERANGE;
315
316 list_for_each_entry(tmp, &mem_segs, list) {
317 if (seg->start >= tmp->start + tmp->size)
318 continue;
319 if (seg->start + seg->size <= tmp->start)
320 continue;
321 return -ENOSPC;
322 }
323 list_add(&seg->list, &mem_segs);
324 return 0;
325 }
326
327 /*
328 * Remove memory segment from the segment list.
329 */
remove_memory_segment(struct memory_segment * seg)330 static void remove_memory_segment(struct memory_segment *seg)
331 {
332 list_del(&seg->list);
333 }
334
__remove_shared_memory(struct memory_segment * seg)335 static void __remove_shared_memory(struct memory_segment *seg)
336 {
337 remove_memory_segment(seg);
338 vmem_remove_range(seg->start, seg->size);
339 }
340
vmem_remove_mapping(unsigned long start,unsigned long size)341 int vmem_remove_mapping(unsigned long start, unsigned long size)
342 {
343 struct memory_segment *seg;
344 int ret;
345
346 mutex_lock(&vmem_mutex);
347
348 ret = -ENOENT;
349 list_for_each_entry(seg, &mem_segs, list) {
350 if (seg->start == start && seg->size == size)
351 break;
352 }
353
354 if (seg->start != start || seg->size != size)
355 goto out;
356
357 ret = 0;
358 __remove_shared_memory(seg);
359 kfree(seg);
360 out:
361 mutex_unlock(&vmem_mutex);
362 return ret;
363 }
364
vmem_add_mapping(unsigned long start,unsigned long size)365 int vmem_add_mapping(unsigned long start, unsigned long size)
366 {
367 struct memory_segment *seg;
368 int ret;
369
370 mutex_lock(&vmem_mutex);
371 ret = -ENOMEM;
372 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
373 if (!seg)
374 goto out;
375 seg->start = start;
376 seg->size = size;
377
378 ret = insert_memory_segment(seg);
379 if (ret)
380 goto out_free;
381
382 ret = vmem_add_mem(start, size);
383 if (ret)
384 goto out_remove;
385 goto out;
386
387 out_remove:
388 __remove_shared_memory(seg);
389 out_free:
390 kfree(seg);
391 out:
392 mutex_unlock(&vmem_mutex);
393 return ret;
394 }
395
396 /*
397 * map whole physical memory to virtual memory (identity mapping)
398 * we reserve enough space in the vmalloc area for vmemmap to hotplug
399 * additional memory segments.
400 */
vmem_map_init(void)401 void __init vmem_map_init(void)
402 {
403 struct memblock_region *reg;
404
405 for_each_memblock(memory, reg)
406 vmem_add_mem(reg->base, reg->size);
407 __set_memory((unsigned long)_stext,
408 (unsigned long)(_etext - _stext) >> PAGE_SHIFT,
409 SET_MEMORY_RO | SET_MEMORY_X);
410 __set_memory((unsigned long)_etext,
411 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
412 SET_MEMORY_RO);
413 __set_memory((unsigned long)_sinittext,
414 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
415 SET_MEMORY_RO | SET_MEMORY_X);
416 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT,
417 SET_MEMORY_RO | SET_MEMORY_X);
418 pr_info("Write protected kernel read-only data: %luk\n",
419 (unsigned long)(__end_rodata - _stext) >> 10);
420 }
421
422 /*
423 * Convert memblock.memory to a memory segment list so there is a single
424 * list that contains all memory segments.
425 */
vmem_convert_memory_chunk(void)426 static int __init vmem_convert_memory_chunk(void)
427 {
428 struct memblock_region *reg;
429 struct memory_segment *seg;
430
431 mutex_lock(&vmem_mutex);
432 for_each_memblock(memory, reg) {
433 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
434 if (!seg)
435 panic("Out of memory...\n");
436 seg->start = reg->base;
437 seg->size = reg->size;
438 insert_memory_segment(seg);
439 }
440 mutex_unlock(&vmem_mutex);
441 return 0;
442 }
443
444 core_initcall(vmem_convert_memory_chunk);
445
