1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2016, Rashmica Gupta, IBM Corp.
4 *
5 * This traverses the kernel virtual memory and dumps the pages that are in
6 * the hash pagetable, along with their flags to
7 * /sys/kernel/debug/kernel_hash_pagetable.
8 *
9 * If radix is enabled then there is no hash page table and so no debugfs file
10 * is generated.
11 */
12 #include <linux/debugfs.h>
13 #include <linux/fs.h>
14 #include <linux/io.h>
15 #include <linux/mm.h>
16 #include <linux/sched.h>
17 #include <linux/seq_file.h>
18 #include <linux/const.h>
19 #include <asm/page.h>
20 #include <asm/plpar_wrappers.h>
21 #include <linux/memblock.h>
22 #include <asm/firmware.h>
23 #include <asm/pgalloc.h>
24
25 struct pg_state {
26 struct seq_file *seq;
27 const struct addr_marker *marker;
28 unsigned long start_address;
29 unsigned int level;
30 u64 current_flags;
31 };
32
33 struct addr_marker {
34 unsigned long start_address;
35 const char *name;
36 };
37
38 static struct addr_marker address_markers[] = {
39 { 0, "Start of kernel VM" },
40 { 0, "vmalloc() Area" },
41 { 0, "vmalloc() End" },
42 { 0, "isa I/O start" },
43 { 0, "isa I/O end" },
44 { 0, "phb I/O start" },
45 { 0, "phb I/O end" },
46 { 0, "I/O remap start" },
47 { 0, "I/O remap end" },
48 { 0, "vmemmap start" },
49 { -1, NULL },
50 };
51
52 struct flag_info {
53 u64 mask;
54 u64 val;
55 const char *set;
56 const char *clear;
57 bool is_val;
58 int shift;
59 };
60
61 static const struct flag_info v_flag_array[] = {
62 {
63 .mask = SLB_VSID_B,
64 .val = SLB_VSID_B_256M,
65 .set = "ssize: 256M",
66 .clear = "ssize: 1T ",
67 }, {
68 .mask = HPTE_V_SECONDARY,
69 .val = HPTE_V_SECONDARY,
70 .set = "secondary",
71 .clear = "primary ",
72 }, {
73 .mask = HPTE_V_VALID,
74 .val = HPTE_V_VALID,
75 .set = "valid ",
76 .clear = "invalid",
77 }, {
78 .mask = HPTE_V_BOLTED,
79 .val = HPTE_V_BOLTED,
80 .set = "bolted",
81 .clear = "",
82 }
83 };
84
85 static const struct flag_info r_flag_array[] = {
86 {
87 .mask = HPTE_R_PP0 | HPTE_R_PP,
88 .val = PP_RWXX,
89 .set = "prot:RW--",
90 }, {
91 .mask = HPTE_R_PP0 | HPTE_R_PP,
92 .val = PP_RWRX,
93 .set = "prot:RWR-",
94 }, {
95 .mask = HPTE_R_PP0 | HPTE_R_PP,
96 .val = PP_RWRW,
97 .set = "prot:RWRW",
98 }, {
99 .mask = HPTE_R_PP0 | HPTE_R_PP,
100 .val = PP_RXRX,
101 .set = "prot:R-R-",
102 }, {
103 .mask = HPTE_R_PP0 | HPTE_R_PP,
104 .val = PP_RXXX,
105 .set = "prot:R---",
106 }, {
107 .mask = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
108 .val = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
109 .set = "key",
110 .clear = "",
111 .is_val = true,
112 }, {
113 .mask = HPTE_R_R,
114 .val = HPTE_R_R,
115 .set = "ref",
116 .clear = " ",
117 }, {
118 .mask = HPTE_R_C,
119 .val = HPTE_R_C,
120 .set = "changed",
121 .clear = " ",
122 }, {
123 .mask = HPTE_R_N,
124 .val = HPTE_R_N,
125 .set = "no execute",
126 }, {
127 .mask = HPTE_R_WIMG,
128 .val = HPTE_R_W,
129 .set = "writethru",
130 }, {
131 .mask = HPTE_R_WIMG,
132 .val = HPTE_R_I,
133 .set = "no cache",
134 }, {
135 .mask = HPTE_R_WIMG,
136 .val = HPTE_R_G,
137 .set = "guarded",
138 }
139 };
140
141 static int calculate_pagesize(struct pg_state *st, int ps, char s[])
142 {
143 static const char units[] = "BKMGTPE";
144 const char *unit = units;
145
146 while (ps > 9 && unit[1]) {
147 ps -= 10;
148 unit++;
149 }
150 seq_printf(st->seq, " %s_ps: %i%c\t", s, 1<<ps, *unit);
151 return ps;
152 }
153
154 static void dump_flag_info(struct pg_state *st, const struct flag_info
155 *flag, u64 pte, int num)
156 {
157 unsigned int i;
158
159 for (i = 0; i < num; i++, flag++) {
160 const char *s = NULL;
161 u64 val;
162
163 /* flag not defined so don't check it */
164 if (flag->mask == 0)
165 continue;
166 /* Some 'flags' are actually values */
167 if (flag->is_val) {
168 val = pte & flag->val;
169 if (flag->shift)
170 val = val >> flag->shift;
171 seq_printf(st->seq, " %s:%llx", flag->set, val);
172 } else {
173 if ((pte & flag->mask) == flag->val)
174 s = flag->set;
175 else
176 s = flag->clear;
177 if (s)
178 seq_printf(st->seq, " %s", s);
179 }
180 }
181 }
182
183 static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r,
184 unsigned long rpn, int bps, int aps, unsigned long lp)
185 {
186 int aps_index;
187
188 while (ea >= st->marker[1].start_address) {
189 st->marker++;
190 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
191 }
192 seq_printf(st->seq, "0x%lx:\t", ea);
193 seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v));
194 dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array));
195 seq_printf(st->seq, " rpn: %lx\t", rpn);
196 dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array));
197
198 calculate_pagesize(st, bps, "base");
199 aps_index = calculate_pagesize(st, aps, "actual");
200 if (aps_index != 2)
201 seq_printf(st->seq, "LP enc: %lx", lp);
202 seq_putc(st->seq, '\n');
203 }
204
205
206 static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
207 *r)
208 {
209 struct hash_pte *hptep;
210 unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v;
211 int i, ssize = mmu_kernel_ssize;
212 unsigned long shift = mmu_psize_defs[psize].shift;
213
214 /* calculate hash */
215 vsid = get_kernel_vsid(ea, ssize);
216 vpn = hpt_vpn(ea, vsid, ssize);
217 hash = hpt_hash(vpn, shift, ssize);
218 want_v = hpte_encode_avpn(vpn, psize, ssize);
219
220 /* to check in the secondary hash table, we invert the hash */
221 if (!primary)
222 hash = ~hash;
223 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
224 for (i = 0; i < HPTES_PER_GROUP; i++) {
225 hptep = htab_address + hpte_group;
226 hpte_v = be64_to_cpu(hptep->v);
227
228 if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
229 /* HPTE matches */
230 *v = be64_to_cpu(hptep->v);
231 *r = be64_to_cpu(hptep->r);
232 return 0;
233 }
234 ++hpte_group;
235 }
236 return -1;
237 }
238
239 static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
240 {
241 struct {
242 unsigned long v;
243 unsigned long r;
244 } ptes[4];
245 unsigned long vsid, vpn, hash, hpte_group, want_v;
246 int i, j, ssize = mmu_kernel_ssize;
247 long lpar_rc = 0;
248 unsigned long shift = mmu_psize_defs[psize].shift;
249
250 /* calculate hash */
251 vsid = get_kernel_vsid(ea, ssize);
252 vpn = hpt_vpn(ea, vsid, ssize);
253 hash = hpt_hash(vpn, shift, ssize);
254 want_v = hpte_encode_avpn(vpn, psize, ssize);
255
256 /* to check in the secondary hash table, we invert the hash */
257 if (!primary)
258 hash = ~hash;
259 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
260 /* see if we can find an entry in the hpte with this hash */
261 for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
262 lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
263
264 if (lpar_rc)
265 continue;
266 for (j = 0; j < 4; j++) {
267 if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
268 (ptes[j].v & HPTE_V_VALID)) {
269 /* HPTE matches */
270 *v = ptes[j].v;
271 *r = ptes[j].r;
272 return 0;
273 }
274 }
275 }
276 return -1;
277 }
278
279 static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
280 unsigned long *lp_bits)
281 {
282 struct mmu_psize_def entry;
283 unsigned long arpn, mask, lp;
284 int penc = -2, idx = 0, shift;
285
286 /*.
287 * The LP field has 8 bits. Depending on the actual page size, some of
288 * these bits are concatenated with the APRN to get the RPN. The rest
289 * of the bits in the LP field is the LP value and is an encoding for
290 * the base page size and the actual page size.
291 *
292 * - find the mmu entry for our base page size
293 * - go through all page encodings and use the associated mask to
294 * find an encoding that matches our encoding in the LP field.
295 */
296 arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
297 lp = arpn & 0xff;
298
299 entry = mmu_psize_defs[bps];
300 while (idx < MMU_PAGE_COUNT) {
301 penc = entry.penc[idx];
302 if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
303 shift = mmu_psize_defs[idx].shift - HPTE_R_RPN_SHIFT;
304 mask = (0x1 << (shift)) - 1;
305 if ((lp & mask) == penc) {
306 *aps = mmu_psize_to_shift(idx);
307 *lp_bits = lp & mask;
308 *rpn = arpn >> shift;
309 return;
310 }
311 }
312 idx++;
313 }
314 }
315
316 static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
317 u64 *r)
318 {
319 if (IS_ENABLED(CONFIG_PPC_PSERIES) && firmware_has_feature(FW_FEATURE_LPAR))
320 return pseries_find(ea, psize, primary, v, r);
321
322 return native_find(ea, psize, primary, v, r);
323 }
324
325 static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
326 {
327 unsigned long slot;
328 u64 v = 0, r = 0;
329 unsigned long rpn, lp_bits;
330 int base_psize = 0, actual_psize = 0;
331
332 if (ea < PAGE_OFFSET)
333 return -1;
334
335 /* Look in primary table */
336 slot = base_hpte_find(ea, psize, true, &v, &r);
337
338 /* Look in secondary table */
339 if (slot == -1)
340 slot = base_hpte_find(ea, psize, false, &v, &r);
341
342 /* No entry found */
343 if (slot == -1)
344 return -1;
345
346 /*
347 * We found an entry in the hash page table:
348 * - check that this has the same base page
349 * - find the actual page size
350 * - find the RPN
351 */
352 base_psize = mmu_psize_to_shift(psize);
353
354 if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
355 decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
356 } else {
357 /* 4K actual page size */
358 actual_psize = 12;
359 rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
360 /* In this case there are no LP bits */
361 lp_bits = -1;
362 }
363 /*
364 * We didn't find a matching encoding, so the PTE we found isn't for
365 * this address.
366 */
367 if (actual_psize == -1)
368 return -1;
369
370 dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
371 return 0;
372 }
373
374 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
375 {
376 pte_t *pte = pte_offset_kernel(pmd, 0);
377 unsigned long addr, pteval, psize;
378 int i, status;
379
380 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
381 addr = start + i * PAGE_SIZE;
382 pteval = pte_val(*pte);
383
384 if (addr < VMALLOC_END)
385 psize = mmu_vmalloc_psize;
386 else
387 psize = mmu_io_psize;
388
389 /* check for secret 4K mappings */
390 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) &&
391 ((pteval & H_PAGE_COMBO) == H_PAGE_COMBO ||
392 (pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
393 psize = mmu_io_psize;
394
395 /* check for hashpte */
396 status = hpte_find(st, addr, psize);
397
398 if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
399 && (status != -1)) {
400 /* found a hpte that is not in the linux page tables */
401 seq_printf(st->seq, "page probably bolted before linux"
402 " pagetables were set: addr:%lx, pteval:%lx\n",
403 addr, pteval);
404 }
405 }
406 }
407
408 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
409 {
410 pmd_t *pmd = pmd_offset(pud, 0);
411 unsigned long addr;
412 unsigned int i;
413
414 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
415 addr = start + i * PMD_SIZE;
416 if (!pmd_none(*pmd))
417 /* pmd exists */
418 walk_pte(st, pmd, addr);
419 }
420 }
421
422 static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
423 {
424 pud_t *pud = pud_offset(p4d, 0);
425 unsigned long addr;
426 unsigned int i;
427
428 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
429 addr = start + i * PUD_SIZE;
430 if (!pud_none(*pud))
431 /* pud exists */
432 walk_pmd(st, pud, addr);
433 }
434 }
435
436 static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
437 {
438 p4d_t *p4d = p4d_offset(pgd, 0);
439 unsigned long addr;
440 unsigned int i;
441
442 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
443 addr = start + i * P4D_SIZE;
444 if (!p4d_none(*p4d))
445 /* p4d exists */
446 walk_pud(st, p4d, addr);
447 }
448 }
449
450 static void walk_pagetables(struct pg_state *st)
451 {
452 pgd_t *pgd = pgd_offset_k(0UL);
453 unsigned int i;
454 unsigned long addr;
455
456 /*
457 * Traverse the linux pagetable structure and dump pages that are in
458 * the hash pagetable.
459 */
460 for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
461 addr = KERN_VIRT_START + i * PGDIR_SIZE;
462 if (!pgd_none(*pgd))
463 /* pgd exists */
464 walk_p4d(st, pgd, addr);
465 }
466 }
467
468
469 static void walk_linearmapping(struct pg_state *st)
470 {
471 unsigned long addr;
472
473 /*
474 * Traverse the linear mapping section of virtual memory and dump pages
475 * that are in the hash pagetable.
476 */
477 unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift;
478
479 for (addr = PAGE_OFFSET; addr < PAGE_OFFSET +
480 memblock_end_of_DRAM(); addr += psize)
481 hpte_find(st, addr, mmu_linear_psize);
482 }
483
484 static void walk_vmemmap(struct pg_state *st)
485 {
486 struct vmemmap_backing *ptr = vmemmap_list;
487
488 if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
489 return;
490 /*
491 * Traverse the vmemmaped memory and dump pages that are in the hash
492 * pagetable.
493 */
494 while (ptr) {
495 hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize);
496 ptr = ptr->list;
497 }
498 seq_puts(st->seq, "---[ vmemmap end ]---\n");
499 }
500
501 static void populate_markers(void)
502 {
503 address_markers[0].start_address = PAGE_OFFSET;
504 address_markers[1].start_address = VMALLOC_START;
505 address_markers[2].start_address = VMALLOC_END;
506 address_markers[3].start_address = ISA_IO_BASE;
507 address_markers[4].start_address = ISA_IO_END;
508 address_markers[5].start_address = PHB_IO_BASE;
509 address_markers[6].start_address = PHB_IO_END;
510 address_markers[7].start_address = IOREMAP_BASE;
511 address_markers[8].start_address = IOREMAP_END;
512 address_markers[9].start_address = H_VMEMMAP_START;
513 }
514
515 static int ptdump_show(struct seq_file *m, void *v)
516 {
517 struct pg_state st = {
518 .seq = m,
519 .start_address = PAGE_OFFSET,
520 .marker = address_markers,
521 };
522 /*
523 * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and
524 * dump pages that are in the hash pagetable.
525 */
526 walk_linearmapping(&st);
527 walk_pagetables(&st);
528 walk_vmemmap(&st);
529 return 0;
530 }
531
532 DEFINE_SHOW_ATTRIBUTE(ptdump);
533
534 static int ptdump_init(void)
535 {
536 if (!radix_enabled()) {
537 populate_markers();
538 debugfs_create_file("kernel_hash_pagetable", 0400, NULL, NULL,
539 &ptdump_fops);
540 }
541 return 0;
542 }
543 device_initcall(ptdump_init);
544
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