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/setup.h>
17 #include <asm/tlbflush.h>
18 #include <asm/sections.h>
19 #include <asm/set_memory.h>
20
21 static DEFINE_MUTEX(vmem_mutex);
22
vmem_alloc_pages(unsigned int order)23 static void __ref *vmem_alloc_pages(unsigned int order)
24 {
25 unsigned long size = PAGE_SIZE << order;
26
27 if (slab_is_available())
28 return (void *)__get_free_pages(GFP_KERNEL, order);
29 return (void *) memblock_phys_alloc(size, size);
30 }
31
vmem_free_pages(unsigned long addr,int order)32 static void vmem_free_pages(unsigned long addr, int order)
33 {
34 /* We don't expect boot memory to be removed ever. */
35 if (!slab_is_available() ||
36 WARN_ON_ONCE(PageReserved(phys_to_page(addr))))
37 return;
38 free_pages(addr, order);
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
vmem_pte_free(unsigned long * table)66 static void vmem_pte_free(unsigned long *table)
67 {
68 /* We don't expect boot memory to be removed ever. */
69 if (!slab_is_available() ||
70 WARN_ON_ONCE(PageReserved(virt_to_page(table))))
71 return;
72 page_table_free(&init_mm, table);
73 }
74
75 #define PAGE_UNUSED 0xFD
76
77 /*
78 * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
79 * from unused_pmd_start to next PMD_SIZE boundary.
80 */
81 static unsigned long unused_pmd_start;
82
vmemmap_flush_unused_pmd(void)83 static void vmemmap_flush_unused_pmd(void)
84 {
85 if (!unused_pmd_start)
86 return;
87 memset(__va(unused_pmd_start), PAGE_UNUSED,
88 ALIGN(unused_pmd_start, PMD_SIZE) - unused_pmd_start);
89 unused_pmd_start = 0;
90 }
91
__vmemmap_use_sub_pmd(unsigned long start,unsigned long end)92 static void __vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
93 {
94 /*
95 * As we expect to add in the same granularity as we remove, it's
96 * sufficient to mark only some piece used to block the memmap page from
97 * getting removed (just in case the memmap never gets initialized,
98 * e.g., because the memory block never gets onlined).
99 */
100 memset(__va(start), 0, sizeof(struct page));
101 }
102
vmemmap_use_sub_pmd(unsigned long start,unsigned long end)103 static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
104 {
105 /*
106 * We only optimize if the new used range directly follows the
107 * previously unused range (esp., when populating consecutive sections).
108 */
109 if (unused_pmd_start == start) {
110 unused_pmd_start = end;
111 if (likely(IS_ALIGNED(unused_pmd_start, PMD_SIZE)))
112 unused_pmd_start = 0;
113 return;
114 }
115 vmemmap_flush_unused_pmd();
116 __vmemmap_use_sub_pmd(start, end);
117 }
118
vmemmap_use_new_sub_pmd(unsigned long start,unsigned long end)119 static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
120 {
121 void *page = __va(ALIGN_DOWN(start, PMD_SIZE));
122
123 vmemmap_flush_unused_pmd();
124
125 /* Could be our memmap page is filled with PAGE_UNUSED already ... */
126 __vmemmap_use_sub_pmd(start, end);
127
128 /* Mark the unused parts of the new memmap page PAGE_UNUSED. */
129 if (!IS_ALIGNED(start, PMD_SIZE))
130 memset(page, PAGE_UNUSED, start - __pa(page));
131 /*
132 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
133 * consecutive sections. Remember for the last added PMD the last
134 * unused range in the populated PMD.
135 */
136 if (!IS_ALIGNED(end, PMD_SIZE))
137 unused_pmd_start = end;
138 }
139
140 /* Returns true if the PMD is completely unused and can be freed. */
vmemmap_unuse_sub_pmd(unsigned long start,unsigned long end)141 static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
142 {
143 void *page = __va(ALIGN_DOWN(start, PMD_SIZE));
144
145 vmemmap_flush_unused_pmd();
146 memset(__va(start), PAGE_UNUSED, end - start);
147 return !memchr_inv(page, PAGE_UNUSED, PMD_SIZE);
148 }
149
150 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
modify_pte_table(pmd_t * pmd,unsigned long addr,unsigned long end,bool add,bool direct)151 static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
152 unsigned long end, bool add, bool direct)
153 {
154 unsigned long prot, pages = 0;
155 int ret = -ENOMEM;
156 pte_t *pte;
157
158 prot = pgprot_val(PAGE_KERNEL);
159 if (!MACHINE_HAS_NX)
160 prot &= ~_PAGE_NOEXEC;
161
162 pte = pte_offset_kernel(pmd, addr);
163 for (; addr < end; addr += PAGE_SIZE, pte++) {
164 if (!add) {
165 if (pte_none(*pte))
166 continue;
167 if (!direct)
168 vmem_free_pages(pfn_to_phys(pte_pfn(*pte)), 0);
169 pte_clear(&init_mm, addr, pte);
170 } else if (pte_none(*pte)) {
171 if (!direct) {
172 void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
173
174 if (!new_page)
175 goto out;
176 pte_val(*pte) = __pa(new_page) | prot;
177 } else {
178 pte_val(*pte) = addr | prot;
179 }
180 } else {
181 continue;
182 }
183 pages++;
184 }
185 ret = 0;
186 out:
187 if (direct)
188 update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
189 return ret;
190 }
191
try_free_pte_table(pmd_t * pmd,unsigned long start)192 static void try_free_pte_table(pmd_t *pmd, unsigned long start)
193 {
194 pte_t *pte;
195 int i;
196
197 /* We can safely assume this is fully in 1:1 mapping & vmemmap area */
198 pte = pte_offset_kernel(pmd, start);
199 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
200 if (!pte_none(*pte))
201 return;
202 }
203 vmem_pte_free(__va(pmd_deref(*pmd)));
204 pmd_clear(pmd);
205 }
206
207 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
modify_pmd_table(pud_t * pud,unsigned long addr,unsigned long end,bool add,bool direct)208 static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
209 unsigned long end, bool add, bool direct)
210 {
211 unsigned long next, prot, pages = 0;
212 int ret = -ENOMEM;
213 pmd_t *pmd;
214 pte_t *pte;
215
216 prot = pgprot_val(SEGMENT_KERNEL);
217 if (!MACHINE_HAS_NX)
218 prot &= ~_SEGMENT_ENTRY_NOEXEC;
219
220 pmd = pmd_offset(pud, addr);
221 for (; addr < end; addr = next, pmd++) {
222 next = pmd_addr_end(addr, end);
223 if (!add) {
224 if (pmd_none(*pmd))
225 continue;
226 if (pmd_large(*pmd) && !add) {
227 if (IS_ALIGNED(addr, PMD_SIZE) &&
228 IS_ALIGNED(next, PMD_SIZE)) {
229 if (!direct)
230 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
231 pmd_clear(pmd);
232 pages++;
233 } else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
234 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
235 pmd_clear(pmd);
236 }
237 continue;
238 }
239 } else if (pmd_none(*pmd)) {
240 if (IS_ALIGNED(addr, PMD_SIZE) &&
241 IS_ALIGNED(next, PMD_SIZE) &&
242 MACHINE_HAS_EDAT1 && addr && direct &&
243 !debug_pagealloc_enabled()) {
244 pmd_val(*pmd) = addr | prot;
245 pages++;
246 continue;
247 } else if (!direct && MACHINE_HAS_EDAT1) {
248 void *new_page;
249
250 /*
251 * Use 1MB frames for vmemmap if available. We
252 * always use large frames even if they are only
253 * partially used. Otherwise we would have also
254 * page tables since vmemmap_populate gets
255 * called for each section separately.
256 */
257 new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
258 if (new_page) {
259 pmd_val(*pmd) = __pa(new_page) | prot;
260 if (!IS_ALIGNED(addr, PMD_SIZE) ||
261 !IS_ALIGNED(next, PMD_SIZE)) {
262 vmemmap_use_new_sub_pmd(addr, next);
263 }
264 continue;
265 }
266 }
267 pte = vmem_pte_alloc();
268 if (!pte)
269 goto out;
270 pmd_populate(&init_mm, pmd, pte);
271 } else if (pmd_large(*pmd)) {
272 if (!direct)
273 vmemmap_use_sub_pmd(addr, next);
274 continue;
275 }
276 ret = modify_pte_table(pmd, addr, next, add, direct);
277 if (ret)
278 goto out;
279 if (!add)
280 try_free_pte_table(pmd, addr & PMD_MASK);
281 }
282 ret = 0;
283 out:
284 if (direct)
285 update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
286 return ret;
287 }
288
try_free_pmd_table(pud_t * pud,unsigned long start)289 static void try_free_pmd_table(pud_t *pud, unsigned long start)
290 {
291 const unsigned long end = start + PUD_SIZE;
292 pmd_t *pmd;
293 int i;
294
295 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
296 if (end > VMALLOC_START)
297 return;
298 #ifdef CONFIG_KASAN
299 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
300 return;
301 #endif
302 pmd = pmd_offset(pud, start);
303 for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
304 if (!pmd_none(*pmd))
305 return;
306 vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
307 pud_clear(pud);
308 }
309
modify_pud_table(p4d_t * p4d,unsigned long addr,unsigned long end,bool add,bool direct)310 static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
311 bool add, bool direct)
312 {
313 unsigned long next, prot, pages = 0;
314 int ret = -ENOMEM;
315 pud_t *pud;
316 pmd_t *pmd;
317
318 prot = pgprot_val(REGION3_KERNEL);
319 if (!MACHINE_HAS_NX)
320 prot &= ~_REGION_ENTRY_NOEXEC;
321 pud = pud_offset(p4d, addr);
322 for (; addr < end; addr = next, pud++) {
323 next = pud_addr_end(addr, end);
324 if (!add) {
325 if (pud_none(*pud))
326 continue;
327 if (pud_large(*pud)) {
328 if (IS_ALIGNED(addr, PUD_SIZE) &&
329 IS_ALIGNED(next, PUD_SIZE)) {
330 pud_clear(pud);
331 pages++;
332 }
333 continue;
334 }
335 } else if (pud_none(*pud)) {
336 if (IS_ALIGNED(addr, PUD_SIZE) &&
337 IS_ALIGNED(next, PUD_SIZE) &&
338 MACHINE_HAS_EDAT2 && addr && direct &&
339 !debug_pagealloc_enabled()) {
340 pud_val(*pud) = addr | prot;
341 pages++;
342 continue;
343 }
344 pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
345 if (!pmd)
346 goto out;
347 pud_populate(&init_mm, pud, pmd);
348 } else if (pud_large(*pud)) {
349 continue;
350 }
351 ret = modify_pmd_table(pud, addr, next, add, direct);
352 if (ret)
353 goto out;
354 if (!add)
355 try_free_pmd_table(pud, addr & PUD_MASK);
356 }
357 ret = 0;
358 out:
359 if (direct)
360 update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
361 return ret;
362 }
363
try_free_pud_table(p4d_t * p4d,unsigned long start)364 static void try_free_pud_table(p4d_t *p4d, unsigned long start)
365 {
366 const unsigned long end = start + P4D_SIZE;
367 pud_t *pud;
368 int i;
369
370 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
371 if (end > VMALLOC_START)
372 return;
373 #ifdef CONFIG_KASAN
374 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
375 return;
376 #endif
377
378 pud = pud_offset(p4d, start);
379 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
380 if (!pud_none(*pud))
381 return;
382 }
383 vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
384 p4d_clear(p4d);
385 }
386
modify_p4d_table(pgd_t * pgd,unsigned long addr,unsigned long end,bool add,bool direct)387 static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
388 bool add, bool direct)
389 {
390 unsigned long next;
391 int ret = -ENOMEM;
392 p4d_t *p4d;
393 pud_t *pud;
394
395 p4d = p4d_offset(pgd, addr);
396 for (; addr < end; addr = next, p4d++) {
397 next = p4d_addr_end(addr, end);
398 if (!add) {
399 if (p4d_none(*p4d))
400 continue;
401 } else if (p4d_none(*p4d)) {
402 pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
403 if (!pud)
404 goto out;
405 p4d_populate(&init_mm, p4d, pud);
406 }
407 ret = modify_pud_table(p4d, addr, next, add, direct);
408 if (ret)
409 goto out;
410 if (!add)
411 try_free_pud_table(p4d, addr & P4D_MASK);
412 }
413 ret = 0;
414 out:
415 return ret;
416 }
417
try_free_p4d_table(pgd_t * pgd,unsigned long start)418 static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
419 {
420 const unsigned long end = start + PGDIR_SIZE;
421 p4d_t *p4d;
422 int i;
423
424 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
425 if (end > VMALLOC_START)
426 return;
427 #ifdef CONFIG_KASAN
428 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
429 return;
430 #endif
431
432 p4d = p4d_offset(pgd, start);
433 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
434 if (!p4d_none(*p4d))
435 return;
436 }
437 vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
438 pgd_clear(pgd);
439 }
440
modify_pagetable(unsigned long start,unsigned long end,bool add,bool direct)441 static int modify_pagetable(unsigned long start, unsigned long end, bool add,
442 bool direct)
443 {
444 unsigned long addr, next;
445 int ret = -ENOMEM;
446 pgd_t *pgd;
447 p4d_t *p4d;
448
449 if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
450 return -EINVAL;
451 for (addr = start; addr < end; addr = next) {
452 next = pgd_addr_end(addr, end);
453 pgd = pgd_offset_k(addr);
454
455 if (!add) {
456 if (pgd_none(*pgd))
457 continue;
458 } else if (pgd_none(*pgd)) {
459 p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
460 if (!p4d)
461 goto out;
462 pgd_populate(&init_mm, pgd, p4d);
463 }
464 ret = modify_p4d_table(pgd, addr, next, add, direct);
465 if (ret)
466 goto out;
467 if (!add)
468 try_free_p4d_table(pgd, addr & PGDIR_MASK);
469 }
470 ret = 0;
471 out:
472 if (!add)
473 flush_tlb_kernel_range(start, end);
474 return ret;
475 }
476
add_pagetable(unsigned long start,unsigned long end,bool direct)477 static int add_pagetable(unsigned long start, unsigned long end, bool direct)
478 {
479 return modify_pagetable(start, end, true, direct);
480 }
481
remove_pagetable(unsigned long start,unsigned long end,bool direct)482 static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
483 {
484 return modify_pagetable(start, end, false, direct);
485 }
486
487 /*
488 * Add a physical memory range to the 1:1 mapping.
489 */
vmem_add_range(unsigned long start,unsigned long size)490 static int vmem_add_range(unsigned long start, unsigned long size)
491 {
492 return add_pagetable(start, start + size, true);
493 }
494
495 /*
496 * Remove a physical memory range from the 1:1 mapping.
497 */
vmem_remove_range(unsigned long start,unsigned long size)498 static void vmem_remove_range(unsigned long start, unsigned long size)
499 {
500 remove_pagetable(start, start + size, true);
501 }
502
503 /*
504 * Add a backed mem_map array to the virtual mem_map array.
505 */
vmemmap_populate(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)506 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
507 struct vmem_altmap *altmap)
508 {
509 int ret;
510
511 mutex_lock(&vmem_mutex);
512 /* We don't care about the node, just use NUMA_NO_NODE on allocations */
513 ret = add_pagetable(start, end, false);
514 if (ret)
515 remove_pagetable(start, end, false);
516 mutex_unlock(&vmem_mutex);
517 return ret;
518 }
519
vmemmap_free(unsigned long start,unsigned long end,struct vmem_altmap * altmap)520 void vmemmap_free(unsigned long start, unsigned long end,
521 struct vmem_altmap *altmap)
522 {
523 mutex_lock(&vmem_mutex);
524 remove_pagetable(start, end, false);
525 mutex_unlock(&vmem_mutex);
526 }
527
vmem_remove_mapping(unsigned long start,unsigned long size)528 void vmem_remove_mapping(unsigned long start, unsigned long size)
529 {
530 mutex_lock(&vmem_mutex);
531 vmem_remove_range(start, size);
532 mutex_unlock(&vmem_mutex);
533 }
534
vmem_add_mapping(unsigned long start,unsigned long size)535 int vmem_add_mapping(unsigned long start, unsigned long size)
536 {
537 int ret;
538
539 if (start + size > VMEM_MAX_PHYS ||
540 start + size < start)
541 return -ERANGE;
542
543 mutex_lock(&vmem_mutex);
544 ret = vmem_add_range(start, size);
545 if (ret)
546 vmem_remove_range(start, size);
547 mutex_unlock(&vmem_mutex);
548 return ret;
549 }
550
551 /*
552 * map whole physical memory to virtual memory (identity mapping)
553 * we reserve enough space in the vmalloc area for vmemmap to hotplug
554 * additional memory segments.
555 */
vmem_map_init(void)556 void __init vmem_map_init(void)
557 {
558 phys_addr_t base, end;
559 u64 i;
560
561 for_each_mem_range(i, &base, &end)
562 vmem_add_range(base, end - base);
563 __set_memory((unsigned long)_stext,
564 (unsigned long)(_etext - _stext) >> PAGE_SHIFT,
565 SET_MEMORY_RO | SET_MEMORY_X);
566 __set_memory((unsigned long)_etext,
567 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
568 SET_MEMORY_RO);
569 __set_memory((unsigned long)_sinittext,
570 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
571 SET_MEMORY_RO | SET_MEMORY_X);
572 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT,
573 SET_MEMORY_RO | SET_MEMORY_X);
574
575 /* we need lowcore executable for our LPSWE instructions */
576 set_memory_x(0, 1);
577
578 pr_info("Write protected kernel read-only data: %luk\n",
579 (unsigned long)(__end_rodata - _stext) >> 10);
580 }
581