1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2011
4 * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
5 */
6 #include <linux/hugetlb.h>
7 #include <linux/proc_fs.h>
8 #include <linux/vmalloc.h>
9 #include <linux/mm.h>
10 #include <asm/cacheflush.h>
11 #include <asm/facility.h>
12 #include <asm/pgalloc.h>
13 #include <asm/kfence.h>
14 #include <asm/page.h>
15 #include <asm/set_memory.h>
16
17 static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
18 {
19 asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],1,0"
20 : [addr] "+a" (addr) : [skey] "d" (skey));
21 return addr;
22 }
23
24 void __storage_key_init_range(unsigned long start, unsigned long end)
25 {
26 unsigned long boundary, size;
27
28 while (start < end) {
29 if (MACHINE_HAS_EDAT1) {
30 /* set storage keys for a 1MB frame */
31 size = 1UL << 20;
32 boundary = (start + size) & ~(size - 1);
33 if (boundary <= end) {
34 do {
35 start = sske_frame(start, PAGE_DEFAULT_KEY);
36 } while (start < boundary);
37 continue;
38 }
39 }
40 page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
41 start += PAGE_SIZE;
42 }
43 }
44
45 #ifdef CONFIG_PROC_FS
46 atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
47
48 void arch_report_meminfo(struct seq_file *m)
49 {
50 seq_printf(m, "DirectMap4k: %8lu kB\n",
51 atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
52 seq_printf(m, "DirectMap1M: %8lu kB\n",
53 atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
54 seq_printf(m, "DirectMap2G: %8lu kB\n",
55 atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
56 }
57 #endif /* CONFIG_PROC_FS */
58
59 static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
60 unsigned long dtt)
61 {
62 unsigned long *table, mask;
63
64 mask = 0;
65 if (MACHINE_HAS_EDAT2) {
66 switch (dtt) {
67 case CRDTE_DTT_REGION3:
68 mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
69 break;
70 case CRDTE_DTT_SEGMENT:
71 mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
72 break;
73 case CRDTE_DTT_PAGE:
74 mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
75 break;
76 }
77 table = (unsigned long *)((unsigned long)old & mask);
78 crdte(*old, new, table, dtt, addr, get_lowcore()->kernel_asce.val);
79 } else if (MACHINE_HAS_IDTE) {
80 cspg(old, *old, new);
81 } else {
82 csp((unsigned int *)old + 1, *old, new);
83 }
84 }
85
86 static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
87 unsigned long flags)
88 {
89 pte_t *ptep, new;
90
91 if (flags == SET_MEMORY_4K)
92 return 0;
93 ptep = pte_offset_kernel(pmdp, addr);
94 do {
95 new = *ptep;
96 if (pte_none(new))
97 return -EINVAL;
98 if (flags & SET_MEMORY_RO)
99 new = pte_wrprotect(new);
100 else if (flags & SET_MEMORY_RW)
101 new = pte_mkwrite_novma(pte_mkdirty(new));
102 if (flags & SET_MEMORY_NX)
103 new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
104 else if (flags & SET_MEMORY_X)
105 new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
106 if (flags & SET_MEMORY_INV) {
107 new = set_pte_bit(new, __pgprot(_PAGE_INVALID));
108 } else if (flags & SET_MEMORY_DEF) {
109 new = __pte(pte_val(new) & PAGE_MASK);
110 new = set_pte_bit(new, PAGE_KERNEL);
111 if (!MACHINE_HAS_NX)
112 new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
113 }
114 pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
115 ptep++;
116 addr += PAGE_SIZE;
117 cond_resched();
118 } while (addr < end);
119 return 0;
120 }
121
122 static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
123 {
124 unsigned long pte_addr, prot;
125 pte_t *pt_dir, *ptep;
126 pmd_t new;
127 int i, ro, nx;
128
129 pt_dir = vmem_pte_alloc();
130 if (!pt_dir)
131 return -ENOMEM;
132 pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
133 ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
134 nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
135 prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
136 if (!nx)
137 prot &= ~_PAGE_NOEXEC;
138 ptep = pt_dir;
139 for (i = 0; i < PTRS_PER_PTE; i++) {
140 set_pte(ptep, __pte(pte_addr | prot));
141 pte_addr += PAGE_SIZE;
142 ptep++;
143 }
144 new = __pmd(__pa(pt_dir) | _SEGMENT_ENTRY);
145 pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
146 update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
147 update_page_count(PG_DIRECT_MAP_1M, -1);
148 return 0;
149 }
150
151 static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
152 unsigned long flags)
153 {
154 pmd_t new = *pmdp;
155
156 if (flags & SET_MEMORY_RO)
157 new = pmd_wrprotect(new);
158 else if (flags & SET_MEMORY_RW)
159 new = pmd_mkwrite_novma(pmd_mkdirty(new));
160 if (flags & SET_MEMORY_NX)
161 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
162 else if (flags & SET_MEMORY_X)
163 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
164 if (flags & SET_MEMORY_INV) {
165 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
166 } else if (flags & SET_MEMORY_DEF) {
167 new = __pmd(pmd_val(new) & PMD_MASK);
168 new = set_pmd_bit(new, SEGMENT_KERNEL);
169 if (!MACHINE_HAS_NX)
170 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
171 }
172 pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
173 }
174
175 static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
176 unsigned long flags)
177 {
178 unsigned long next;
179 int need_split;
180 pmd_t *pmdp;
181 int rc = 0;
182
183 pmdp = pmd_offset(pudp, addr);
184 do {
185 if (pmd_none(*pmdp))
186 return -EINVAL;
187 next = pmd_addr_end(addr, end);
188 if (pmd_leaf(*pmdp)) {
189 need_split = !!(flags & SET_MEMORY_4K);
190 need_split |= !!(addr & ~PMD_MASK);
191 need_split |= !!(addr + PMD_SIZE > next);
192 if (need_split) {
193 rc = split_pmd_page(pmdp, addr);
194 if (rc)
195 return rc;
196 continue;
197 }
198 modify_pmd_page(pmdp, addr, flags);
199 } else {
200 rc = walk_pte_level(pmdp, addr, next, flags);
201 if (rc)
202 return rc;
203 }
204 pmdp++;
205 addr = next;
206 cond_resched();
207 } while (addr < end);
208 return rc;
209 }
210
211 static int split_pud_page(pud_t *pudp, unsigned long addr)
212 {
213 unsigned long pmd_addr, prot;
214 pmd_t *pm_dir, *pmdp;
215 pud_t new;
216 int i, ro, nx;
217
218 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
219 if (!pm_dir)
220 return -ENOMEM;
221 pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
222 ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
223 nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
224 prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
225 if (!nx)
226 prot &= ~_SEGMENT_ENTRY_NOEXEC;
227 pmdp = pm_dir;
228 for (i = 0; i < PTRS_PER_PMD; i++) {
229 set_pmd(pmdp, __pmd(pmd_addr | prot));
230 pmd_addr += PMD_SIZE;
231 pmdp++;
232 }
233 new = __pud(__pa(pm_dir) | _REGION3_ENTRY);
234 pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
235 update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
236 update_page_count(PG_DIRECT_MAP_2G, -1);
237 return 0;
238 }
239
240 static void modify_pud_page(pud_t *pudp, unsigned long addr,
241 unsigned long flags)
242 {
243 pud_t new = *pudp;
244
245 if (flags & SET_MEMORY_RO)
246 new = pud_wrprotect(new);
247 else if (flags & SET_MEMORY_RW)
248 new = pud_mkwrite(pud_mkdirty(new));
249 if (flags & SET_MEMORY_NX)
250 new = set_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
251 else if (flags & SET_MEMORY_X)
252 new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
253 if (flags & SET_MEMORY_INV) {
254 new = set_pud_bit(new, __pgprot(_REGION_ENTRY_INVALID));
255 } else if (flags & SET_MEMORY_DEF) {
256 new = __pud(pud_val(new) & PUD_MASK);
257 new = set_pud_bit(new, REGION3_KERNEL);
258 if (!MACHINE_HAS_NX)
259 new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
260 }
261 pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
262 }
263
264 static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
265 unsigned long flags)
266 {
267 unsigned long next;
268 int need_split;
269 pud_t *pudp;
270 int rc = 0;
271
272 pudp = pud_offset(p4d, addr);
273 do {
274 if (pud_none(*pudp))
275 return -EINVAL;
276 next = pud_addr_end(addr, end);
277 if (pud_leaf(*pudp)) {
278 need_split = !!(flags & SET_MEMORY_4K);
279 need_split |= !!(addr & ~PUD_MASK);
280 need_split |= !!(addr + PUD_SIZE > next);
281 if (need_split) {
282 rc = split_pud_page(pudp, addr);
283 if (rc)
284 break;
285 continue;
286 }
287 modify_pud_page(pudp, addr, flags);
288 } else {
289 rc = walk_pmd_level(pudp, addr, next, flags);
290 }
291 pudp++;
292 addr = next;
293 cond_resched();
294 } while (addr < end && !rc);
295 return rc;
296 }
297
298 static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
299 unsigned long flags)
300 {
301 unsigned long next;
302 p4d_t *p4dp;
303 int rc = 0;
304
305 p4dp = p4d_offset(pgd, addr);
306 do {
307 if (p4d_none(*p4dp))
308 return -EINVAL;
309 next = p4d_addr_end(addr, end);
310 rc = walk_pud_level(p4dp, addr, next, flags);
311 p4dp++;
312 addr = next;
313 cond_resched();
314 } while (addr < end && !rc);
315 return rc;
316 }
317
318 DEFINE_MUTEX(cpa_mutex);
319
320 static int change_page_attr(unsigned long addr, unsigned long end,
321 unsigned long flags)
322 {
323 unsigned long next;
324 int rc = -EINVAL;
325 pgd_t *pgdp;
326
327 pgdp = pgd_offset_k(addr);
328 do {
329 if (pgd_none(*pgdp))
330 break;
331 next = pgd_addr_end(addr, end);
332 rc = walk_p4d_level(pgdp, addr, next, flags);
333 if (rc)
334 break;
335 cond_resched();
336 } while (pgdp++, addr = next, addr < end && !rc);
337 return rc;
338 }
339
340 static int change_page_attr_alias(unsigned long addr, unsigned long end,
341 unsigned long flags)
342 {
343 unsigned long alias, offset, va_start, va_end;
344 struct vm_struct *area;
345 int rc = 0;
346
347 /*
348 * Changes to read-only permissions on kernel VA mappings are also
349 * applied to the kernel direct mapping. Execute permissions are
350 * intentionally not transferred to keep all allocated pages within
351 * the direct mapping non-executable.
352 */
353 flags &= SET_MEMORY_RO | SET_MEMORY_RW;
354 if (!flags)
355 return 0;
356 area = NULL;
357 while (addr < end) {
358 if (!area)
359 area = find_vm_area((void *)addr);
360 if (!area || !(area->flags & VM_ALLOC))
361 return 0;
362 va_start = (unsigned long)area->addr;
363 va_end = va_start + area->nr_pages * PAGE_SIZE;
364 offset = (addr - va_start) >> PAGE_SHIFT;
365 alias = (unsigned long)page_address(area->pages[offset]);
366 rc = change_page_attr(alias, alias + PAGE_SIZE, flags);
367 if (rc)
368 break;
369 addr += PAGE_SIZE;
370 if (addr >= va_end)
371 area = NULL;
372 }
373 return rc;
374 }
375
376 int __set_memory(unsigned long addr, unsigned long numpages, unsigned long flags)
377 {
378 unsigned long end;
379 int rc;
380
381 if (!MACHINE_HAS_NX)
382 flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
383 if (!flags)
384 return 0;
385 if (!numpages)
386 return 0;
387 addr &= PAGE_MASK;
388 end = addr + numpages * PAGE_SIZE;
389 mutex_lock(&cpa_mutex);
390 rc = change_page_attr(addr, end, flags);
391 if (rc)
392 goto out;
393 rc = change_page_attr_alias(addr, end, flags);
394 out:
395 mutex_unlock(&cpa_mutex);
396 return rc;
397 }
398
399 int set_direct_map_invalid_noflush(struct page *page)
400 {
401 return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_INV);
402 }
403
404 int set_direct_map_default_noflush(struct page *page)
405 {
406 return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_DEF);
407 }
408
409 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
410
411 static void ipte_range(pte_t *pte, unsigned long address, int nr)
412 {
413 int i;
414
415 if (test_facility(13)) {
416 __ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
417 return;
418 }
419 for (i = 0; i < nr; i++) {
420 __ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
421 address += PAGE_SIZE;
422 pte++;
423 }
424 }
425
426 void __kernel_map_pages(struct page *page, int numpages, int enable)
427 {
428 unsigned long address;
429 pte_t *ptep, pte;
430 int nr, i, j;
431
432 for (i = 0; i < numpages;) {
433 address = (unsigned long)page_to_virt(page + i);
434 ptep = virt_to_kpte(address);
435 nr = (unsigned long)ptep >> ilog2(sizeof(long));
436 nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
437 nr = min(numpages - i, nr);
438 if (enable) {
439 for (j = 0; j < nr; j++) {
440 pte = clear_pte_bit(*ptep, __pgprot(_PAGE_INVALID));
441 set_pte(ptep, pte);
442 address += PAGE_SIZE;
443 ptep++;
444 }
445 } else {
446 ipte_range(ptep, address, nr);
447 }
448 i += nr;
449 }
450 }
451
452 #endif /* CONFIG_DEBUG_PAGEALLOC */
453
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.