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
calculate_pagesize(struct pg_state * st,int ps,char s[])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
dump_flag_info(struct pg_state * st,const struct flag_info * flag,u64 pte,int num)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
dump_hpte_info(struct pg_state * st,unsigned long ea,u64 v,u64 r,unsigned long rpn,int bps,int aps,unsigned long lp)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
native_find(unsigned long ea,int psize,bool primary,u64 * v,u64 * r)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 if (cpu_has_feature(CPU_FTR_ARCH_300))
220 want_v = hpte_old_to_new_v(want_v);
221
222 /* to check in the secondary hash table, we invert the hash */
223 if (!primary)
224 hash = ~hash;
225 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
226 for (i = 0; i < HPTES_PER_GROUP; i++) {
227 hptep = htab_address + hpte_group;
228 hpte_v = be64_to_cpu(hptep->v);
229
230 if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
231 /* HPTE matches */
232 *v = be64_to_cpu(hptep->v);
233 *r = be64_to_cpu(hptep->r);
234 if (cpu_has_feature(CPU_FTR_ARCH_300)) {
235 *v = hpte_new_to_old_v(*v, *r);
236 *r = hpte_new_to_old_r(*r);
237 }
238 return 0;
239 }
240 ++hpte_group;
241 }
242 return -1;
243 }
244
pseries_find(unsigned long ea,int psize,bool primary,u64 * v,u64 * r)245 static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
246 {
247 struct {
248 unsigned long v;
249 unsigned long r;
250 } ptes[4];
251 unsigned long vsid, vpn, hash, hpte_group, want_v;
252 int i, j, ssize = mmu_kernel_ssize;
253 long lpar_rc = 0;
254 unsigned long shift = mmu_psize_defs[psize].shift;
255
256 /* calculate hash */
257 vsid = get_kernel_vsid(ea, ssize);
258 vpn = hpt_vpn(ea, vsid, ssize);
259 hash = hpt_hash(vpn, shift, ssize);
260 want_v = hpte_encode_avpn(vpn, psize, ssize);
261
262 /* to check in the secondary hash table, we invert the hash */
263 if (!primary)
264 hash = ~hash;
265 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
266 /* see if we can find an entry in the hpte with this hash */
267 for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
268 lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
269
270 if (lpar_rc)
271 continue;
272 for (j = 0; j < 4; j++) {
273 if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
274 (ptes[j].v & HPTE_V_VALID)) {
275 /* HPTE matches */
276 *v = ptes[j].v;
277 *r = ptes[j].r;
278 return 0;
279 }
280 }
281 }
282 return -1;
283 }
284
decode_r(int bps,unsigned long r,unsigned long * rpn,int * aps,unsigned long * lp_bits)285 static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
286 unsigned long *lp_bits)
287 {
288 struct mmu_psize_def entry;
289 unsigned long arpn, mask, lp;
290 int penc = -2, idx = 0, shift;
291
292 /*.
293 * The LP field has 8 bits. Depending on the actual page size, some of
294 * these bits are concatenated with the APRN to get the RPN. The rest
295 * of the bits in the LP field is the LP value and is an encoding for
296 * the base page size and the actual page size.
297 *
298 * - find the mmu entry for our base page size
299 * - go through all page encodings and use the associated mask to
300 * find an encoding that matches our encoding in the LP field.
301 */
302 arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
303 lp = arpn & 0xff;
304
305 entry = mmu_psize_defs[bps];
306 while (idx < MMU_PAGE_COUNT) {
307 penc = entry.penc[idx];
308 if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
309 shift = mmu_psize_defs[idx].shift - HPTE_R_RPN_SHIFT;
310 mask = (0x1 << (shift)) - 1;
311 if ((lp & mask) == penc) {
312 *aps = mmu_psize_to_shift(idx);
313 *lp_bits = lp & mask;
314 *rpn = arpn >> shift;
315 return;
316 }
317 }
318 idx++;
319 }
320 }
321
base_hpte_find(unsigned long ea,int psize,bool primary,u64 * v,u64 * r)322 static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
323 u64 *r)
324 {
325 if (IS_ENABLED(CONFIG_PPC_PSERIES) && firmware_has_feature(FW_FEATURE_LPAR))
326 return pseries_find(ea, psize, primary, v, r);
327
328 return native_find(ea, psize, primary, v, r);
329 }
330
hpte_find(struct pg_state * st,unsigned long ea,int psize)331 static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
332 {
333 unsigned long slot;
334 u64 v = 0, r = 0;
335 unsigned long rpn, lp_bits;
336 int base_psize = 0, actual_psize = 0;
337
338 if (ea < PAGE_OFFSET)
339 return -1;
340
341 /* Look in primary table */
342 slot = base_hpte_find(ea, psize, true, &v, &r);
343
344 /* Look in secondary table */
345 if (slot == -1)
346 slot = base_hpte_find(ea, psize, false, &v, &r);
347
348 /* No entry found */
349 if (slot == -1)
350 return -1;
351
352 /*
353 * We found an entry in the hash page table:
354 * - check that this has the same base page
355 * - find the actual page size
356 * - find the RPN
357 */
358 base_psize = mmu_psize_to_shift(psize);
359
360 if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
361 decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
362 } else {
363 /* 4K actual page size */
364 actual_psize = 12;
365 rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
366 /* In this case there are no LP bits */
367 lp_bits = -1;
368 }
369 /*
370 * We didn't find a matching encoding, so the PTE we found isn't for
371 * this address.
372 */
373 if (actual_psize == -1)
374 return -1;
375
376 dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
377 return 0;
378 }
379
walk_pte(struct pg_state * st,pmd_t * pmd,unsigned long start)380 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
381 {
382 pte_t *pte = pte_offset_kernel(pmd, 0);
383 unsigned long addr, pteval, psize;
384 int i, status;
385
386 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
387 addr = start + i * PAGE_SIZE;
388 pteval = pte_val(*pte);
389
390 if (addr < VMALLOC_END)
391 psize = mmu_vmalloc_psize;
392 else
393 psize = mmu_io_psize;
394
395 /* check for secret 4K mappings */
396 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) &&
397 ((pteval & H_PAGE_COMBO) == H_PAGE_COMBO ||
398 (pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
399 psize = mmu_io_psize;
400
401 /* check for hashpte */
402 status = hpte_find(st, addr, psize);
403
404 if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
405 && (status != -1)) {
406 /* found a hpte that is not in the linux page tables */
407 seq_printf(st->seq, "page probably bolted before linux"
408 " pagetables were set: addr:%lx, pteval:%lx\n",
409 addr, pteval);
410 }
411 }
412 }
413
walk_pmd(struct pg_state * st,pud_t * pud,unsigned long start)414 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
415 {
416 pmd_t *pmd = pmd_offset(pud, 0);
417 unsigned long addr;
418 unsigned int i;
419
420 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
421 addr = start + i * PMD_SIZE;
422 if (!pmd_none(*pmd))
423 /* pmd exists */
424 walk_pte(st, pmd, addr);
425 }
426 }
427
walk_pud(struct pg_state * st,p4d_t * p4d,unsigned long start)428 static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
429 {
430 pud_t *pud = pud_offset(p4d, 0);
431 unsigned long addr;
432 unsigned int i;
433
434 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
435 addr = start + i * PUD_SIZE;
436 if (!pud_none(*pud))
437 /* pud exists */
438 walk_pmd(st, pud, addr);
439 }
440 }
441
walk_p4d(struct pg_state * st,pgd_t * pgd,unsigned long start)442 static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
443 {
444 p4d_t *p4d = p4d_offset(pgd, 0);
445 unsigned long addr;
446 unsigned int i;
447
448 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
449 addr = start + i * P4D_SIZE;
450 if (!p4d_none(*p4d))
451 /* p4d exists */
452 walk_pud(st, p4d, addr);
453 }
454 }
455
walk_pagetables(struct pg_state * st)456 static void walk_pagetables(struct pg_state *st)
457 {
458 pgd_t *pgd = pgd_offset_k(0UL);
459 unsigned int i;
460 unsigned long addr;
461
462 /*
463 * Traverse the linux pagetable structure and dump pages that are in
464 * the hash pagetable.
465 */
466 for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
467 addr = KERN_VIRT_START + i * PGDIR_SIZE;
468 if (!pgd_none(*pgd))
469 /* pgd exists */
470 walk_p4d(st, pgd, addr);
471 }
472 }
473
474
walk_linearmapping(struct pg_state * st)475 static void walk_linearmapping(struct pg_state *st)
476 {
477 unsigned long addr;
478
479 /*
480 * Traverse the linear mapping section of virtual memory and dump pages
481 * that are in the hash pagetable.
482 */
483 unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift;
484
485 for (addr = PAGE_OFFSET; addr < PAGE_OFFSET +
486 memblock_end_of_DRAM(); addr += psize)
487 hpte_find(st, addr, mmu_linear_psize);
488 }
489
walk_vmemmap(struct pg_state * st)490 static void walk_vmemmap(struct pg_state *st)
491 {
492 struct vmemmap_backing *ptr = vmemmap_list;
493
494 if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
495 return;
496 /*
497 * Traverse the vmemmaped memory and dump pages that are in the hash
498 * pagetable.
499 */
500 while (ptr) {
501 hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize);
502 ptr = ptr->list;
503 }
504 seq_puts(st->seq, "---[ vmemmap end ]---\n");
505 }
506
populate_markers(void)507 static void populate_markers(void)
508 {
509 address_markers[0].start_address = PAGE_OFFSET;
510 address_markers[1].start_address = VMALLOC_START;
511 address_markers[2].start_address = VMALLOC_END;
512 address_markers[3].start_address = ISA_IO_BASE;
513 address_markers[4].start_address = ISA_IO_END;
514 address_markers[5].start_address = PHB_IO_BASE;
515 address_markers[6].start_address = PHB_IO_END;
516 address_markers[7].start_address = IOREMAP_BASE;
517 address_markers[8].start_address = IOREMAP_END;
518 address_markers[9].start_address = H_VMEMMAP_START;
519 }
520
ptdump_show(struct seq_file * m,void * v)521 static int ptdump_show(struct seq_file *m, void *v)
522 {
523 struct pg_state st = {
524 .seq = m,
525 .start_address = PAGE_OFFSET,
526 .marker = address_markers,
527 };
528 /*
529 * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and
530 * dump pages that are in the hash pagetable.
531 */
532 walk_linearmapping(&st);
533 walk_pagetables(&st);
534 walk_vmemmap(&st);
535 return 0;
536 }
537
538 DEFINE_SHOW_ATTRIBUTE(ptdump);
539
ptdump_init(void)540 static int ptdump_init(void)
541 {
542 if (!radix_enabled()) {
543 populate_markers();
544 debugfs_create_file("kernel_hash_pagetable", 0400, NULL, NULL,
545 &ptdump_fops);
546 }
547 return 0;
548 }
549 device_initcall(ptdump_init);
550