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Linux/arch/powerpc/mm/dump_hashpagetable.c

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  1 /*
  2  * Copyright 2016, Rashmica Gupta, IBM Corp.
  3  *
  4  * This traverses the kernel virtual memory and dumps the pages that are in
  5  * the hash pagetable, along with their flags to
  6  * /sys/kernel/debug/kernel_hash_pagetable.
  7  *
  8  * If radix is enabled then there is no hash page table and so no debugfs file
  9  * is generated.
 10  *
 11  * This program is free software; you can redistribute it and/or
 12  * modify it under the terms of the GNU General Public License
 13  * as published by the Free Software Foundation; version 2
 14  * of the License.
 15  */
 16 #include <linux/debugfs.h>
 17 #include <linux/fs.h>
 18 #include <linux/io.h>
 19 #include <linux/mm.h>
 20 #include <linux/sched.h>
 21 #include <linux/seq_file.h>
 22 #include <asm/pgtable.h>
 23 #include <linux/const.h>
 24 #include <asm/page.h>
 25 #include <asm/pgalloc.h>
 26 #include <asm/plpar_wrappers.h>
 27 #include <linux/memblock.h>
 28 #include <asm/firmware.h>
 29 
 30 struct pg_state {
 31         struct seq_file *seq;
 32         const struct addr_marker *marker;
 33         unsigned long start_address;
 34         unsigned int level;
 35         u64 current_flags;
 36 };
 37 
 38 struct addr_marker {
 39         unsigned long start_address;
 40         const char *name;
 41 };
 42 
 43 static struct addr_marker address_markers[] = {
 44         { 0,    "Start of kernel VM" },
 45         { 0,    "vmalloc() Area" },
 46         { 0,    "vmalloc() End" },
 47         { 0,    "isa I/O start" },
 48         { 0,    "isa I/O end" },
 49         { 0,    "phb I/O start" },
 50         { 0,    "phb I/O end" },
 51         { 0,    "I/O remap start" },
 52         { 0,    "I/O remap end" },
 53         { 0,    "vmemmap start" },
 54         { -1,   NULL },
 55 };
 56 
 57 struct flag_info {
 58         u64             mask;
 59         u64             val;
 60         const char      *set;
 61         const char      *clear;
 62         bool            is_val;
 63         int             shift;
 64 };
 65 
 66 static const struct flag_info v_flag_array[] = {
 67         {
 68                 .mask   = SLB_VSID_B,
 69                 .val    = SLB_VSID_B_256M,
 70                 .set    = "ssize: 256M",
 71                 .clear  = "ssize: 1T  ",
 72         }, {
 73                 .mask   = HPTE_V_SECONDARY,
 74                 .val    = HPTE_V_SECONDARY,
 75                 .set    = "secondary",
 76                 .clear  = "primary  ",
 77         }, {
 78                 .mask   = HPTE_V_VALID,
 79                 .val    = HPTE_V_VALID,
 80                 .set    = "valid  ",
 81                 .clear  = "invalid",
 82         }, {
 83                 .mask   = HPTE_V_BOLTED,
 84                 .val    = HPTE_V_BOLTED,
 85                 .set    = "bolted",
 86                 .clear  = "",
 87         }
 88 };
 89 
 90 static const struct flag_info r_flag_array[] = {
 91         {
 92                 .mask   = HPTE_R_PP0 | HPTE_R_PP,
 93                 .val    = PP_RWXX,
 94                 .set    = "prot:RW--",
 95         }, {
 96                 .mask   = HPTE_R_PP0 | HPTE_R_PP,
 97                 .val    = PP_RWRX,
 98                 .set    = "prot:RWR-",
 99         }, {
100                 .mask   = HPTE_R_PP0 | HPTE_R_PP,
101                 .val    = PP_RWRW,
102                 .set    = "prot:RWRW",
103         }, {
104                 .mask   = HPTE_R_PP0 | HPTE_R_PP,
105                 .val    = PP_RXRX,
106                 .set    = "prot:R-R-",
107         }, {
108                 .mask   = HPTE_R_PP0 | HPTE_R_PP,
109                 .val    = PP_RXXX,
110                 .set    = "prot:R---",
111         }, {
112                 .mask   = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
113                 .val    = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
114                 .set    = "key",
115                 .clear  = "",
116                 .is_val = true,
117         }, {
118                 .mask   = HPTE_R_R,
119                 .val    = HPTE_R_R,
120                 .set    = "ref",
121                 .clear  = "   ",
122         }, {
123                 .mask   = HPTE_R_C,
124                 .val    = HPTE_R_C,
125                 .set    = "changed",
126                 .clear  = "       ",
127         }, {
128                 .mask   = HPTE_R_N,
129                 .val    = HPTE_R_N,
130                 .set    = "no execute",
131         }, {
132                 .mask   = HPTE_R_WIMG,
133                 .val    = HPTE_R_W,
134                 .set    = "writethru",
135         }, {
136                 .mask   = HPTE_R_WIMG,
137                 .val    = HPTE_R_I,
138                 .set    = "no cache",
139         }, {
140                 .mask   = HPTE_R_WIMG,
141                 .val    = HPTE_R_G,
142                 .set    = "guarded",
143         }
144 };
145 
146 static int calculate_pagesize(struct pg_state *st, int ps, char s[])
147 {
148         static const char units[] = "BKMGTPE";
149         const char *unit = units;
150 
151         while (ps > 9 && unit[1]) {
152                 ps -= 10;
153                 unit++;
154         }
155         seq_printf(st->seq, "  %s_ps: %i%c\t", s, 1<<ps, *unit);
156         return ps;
157 }
158 
159 static void dump_flag_info(struct pg_state *st, const struct flag_info
160                 *flag, u64 pte, int num)
161 {
162         unsigned int i;
163 
164         for (i = 0; i < num; i++, flag++) {
165                 const char *s = NULL;
166                 u64 val;
167 
168                 /* flag not defined so don't check it */
169                 if (flag->mask == 0)
170                         continue;
171                 /* Some 'flags' are actually values */
172                 if (flag->is_val) {
173                         val = pte & flag->val;
174                         if (flag->shift)
175                                 val = val >> flag->shift;
176                         seq_printf(st->seq, "  %s:%llx", flag->set, val);
177                 } else {
178                         if ((pte & flag->mask) == flag->val)
179                                 s = flag->set;
180                         else
181                                 s = flag->clear;
182                         if (s)
183                                 seq_printf(st->seq, "  %s", s);
184                 }
185         }
186 }
187 
188 static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r,
189                 unsigned long rpn, int bps, int aps, unsigned long lp)
190 {
191         int aps_index;
192 
193         while (ea >= st->marker[1].start_address) {
194                 st->marker++;
195                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
196         }
197         seq_printf(st->seq, "0x%lx:\t", ea);
198         seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v));
199         dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array));
200         seq_printf(st->seq, "  rpn: %lx\t", rpn);
201         dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array));
202 
203         calculate_pagesize(st, bps, "base");
204         aps_index = calculate_pagesize(st, aps, "actual");
205         if (aps_index != 2)
206                 seq_printf(st->seq, "LP enc: %lx", lp);
207         seq_putc(st->seq, '\n');
208 }
209 
210 
211 static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
212                 *r)
213 {
214         struct hash_pte *hptep;
215         unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v;
216         int i, ssize = mmu_kernel_ssize;
217         unsigned long shift = mmu_psize_defs[psize].shift;
218 
219         /* calculate hash */
220         vsid = get_kernel_vsid(ea, ssize);
221         vpn  = hpt_vpn(ea, vsid, ssize);
222         hash = hpt_hash(vpn, shift, ssize);
223         want_v = hpte_encode_avpn(vpn, psize, ssize);
224 
225         /* to check in the secondary hash table, we invert the hash */
226         if (!primary)
227                 hash = ~hash;
228         hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
229         for (i = 0; i < HPTES_PER_GROUP; i++) {
230                 hptep = htab_address + hpte_group;
231                 hpte_v = be64_to_cpu(hptep->v);
232 
233                 if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
234                         /* HPTE matches */
235                         *v = be64_to_cpu(hptep->v);
236                         *r = be64_to_cpu(hptep->r);
237                         return 0;
238                 }
239                 ++hpte_group;
240         }
241         return -1;
242 }
243 
244 #ifdef CONFIG_PPC_PSERIES
245 static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
246 {
247         struct hash_pte ptes[4];
248         unsigned long vsid, vpn, hash, hpte_group, want_v;
249         int i, j, ssize = mmu_kernel_ssize;
250         long lpar_rc = 0;
251         unsigned long shift = mmu_psize_defs[psize].shift;
252 
253         /* calculate hash */
254         vsid = get_kernel_vsid(ea, ssize);
255         vpn  = hpt_vpn(ea, vsid, ssize);
256         hash = hpt_hash(vpn, shift, ssize);
257         want_v = hpte_encode_avpn(vpn, psize, ssize);
258 
259         /* to check in the secondary hash table, we invert the hash */
260         if (!primary)
261                 hash = ~hash;
262         hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
263         /* see if we can find an entry in the hpte with this hash */
264         for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
265                 lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
266 
267                 if (lpar_rc != H_SUCCESS)
268                         continue;
269                 for (j = 0; j < 4; j++) {
270                         if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
271                                         (ptes[j].v & HPTE_V_VALID)) {
272                                 /* HPTE matches */
273                                 *v = ptes[j].v;
274                                 *r = ptes[j].r;
275                                 return 0;
276                         }
277                 }
278         }
279         return -1;
280 }
281 #endif
282 
283 static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
284                 unsigned long *lp_bits)
285 {
286         struct mmu_psize_def entry;
287         unsigned long arpn, mask, lp;
288         int penc = -2, idx = 0, shift;
289 
290         /*.
291          * The LP field has 8 bits. Depending on the actual page size, some of
292          * these bits are concatenated with the APRN to get the RPN. The rest
293          * of the bits in the LP field is the LP value and is an encoding for
294          * the base page size and the actual page size.
295          *
296          *  -   find the mmu entry for our base page size
297          *  -   go through all page encodings and use the associated mask to
298          *      find an encoding that matches our encoding in the LP field.
299          */
300         arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
301         lp = arpn & 0xff;
302 
303         entry = mmu_psize_defs[bps];
304         while (idx < MMU_PAGE_COUNT) {
305                 penc = entry.penc[idx];
306                 if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
307                         shift = mmu_psize_defs[idx].shift -  HPTE_R_RPN_SHIFT;
308                         mask = (0x1 << (shift)) - 1;
309                         if ((lp & mask) == penc) {
310                                 *aps = mmu_psize_to_shift(idx);
311                                 *lp_bits = lp & mask;
312                                 *rpn = arpn >> shift;
313                                 return;
314                         }
315                 }
316                 idx++;
317         }
318 }
319 
320 static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
321                           u64 *r)
322 {
323 #ifdef CONFIG_PPC_PSERIES
324         if (firmware_has_feature(FW_FEATURE_LPAR))
325                 return pseries_find(ea, psize, primary, v, r);
326 #endif
327         return native_find(ea, psize, primary, v, r);
328 }
329 
330 static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
331 {
332         unsigned long slot;
333         u64 v  = 0, r = 0;
334         unsigned long rpn, lp_bits;
335         int base_psize = 0, actual_psize = 0;
336 
337         if (ea < PAGE_OFFSET)
338                 return -1;
339 
340         /* Look in primary table */
341         slot = base_hpte_find(ea, psize, true, &v, &r);
342 
343         /* Look in secondary table */
344         if (slot == -1)
345                 slot = base_hpte_find(ea, psize, true, &v, &r);
346 
347         /* No entry found */
348         if (slot == -1)
349                 return -1;
350 
351         /*
352          * We found an entry in the hash page table:
353          *  - check that this has the same base page
354          *  - find the actual page size
355          *  - find the RPN
356          */
357         base_psize = mmu_psize_to_shift(psize);
358 
359         if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
360                 decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
361         } else {
362                 /* 4K actual page size */
363                 actual_psize = 12;
364                 rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
365                 /* In this case there are no LP bits */
366                 lp_bits = -1;
367         }
368         /*
369          * We didn't find a matching encoding, so the PTE we found isn't for
370          * this address.
371          */
372         if (actual_psize == -1)
373                 return -1;
374 
375         dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
376         return 0;
377 }
378 
379 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
380 {
381         pte_t *pte = pte_offset_kernel(pmd, 0);
382         unsigned long addr, pteval, psize;
383         int i, status;
384 
385         for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
386                 addr = start + i * PAGE_SIZE;
387                 pteval = pte_val(*pte);
388 
389                 if (addr < VMALLOC_END)
390                         psize = mmu_vmalloc_psize;
391                 else
392                         psize = mmu_io_psize;
393 #ifdef CONFIG_PPC_64K_PAGES
394                 /* check for secret 4K mappings */
395                 if (((pteval & H_PAGE_COMBO) == H_PAGE_COMBO) ||
396                         ((pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
397                         psize = mmu_io_psize;
398 #endif
399                 /* check for hashpte */
400                 status = hpte_find(st, addr, psize);
401 
402                 if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
403                                 && (status != -1)) {
404                 /* found a hpte that is not in the linux page tables */
405                         seq_printf(st->seq, "page probably bolted before linux"
406                                 " pagetables were set: addr:%lx, pteval:%lx\n",
407                                 addr, pteval);
408                 }
409         }
410 }
411 
412 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
413 {
414         pmd_t *pmd = pmd_offset(pud, 0);
415         unsigned long addr;
416         unsigned int i;
417 
418         for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
419                 addr = start + i * PMD_SIZE;
420                 if (!pmd_none(*pmd))
421                         /* pmd exists */
422                         walk_pte(st, pmd, addr);
423         }
424 }
425 
426 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
427 {
428         pud_t *pud = pud_offset(pgd, 0);
429         unsigned long addr;
430         unsigned int i;
431 
432         for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
433                 addr = start + i * PUD_SIZE;
434                 if (!pud_none(*pud))
435                         /* pud exists */
436                         walk_pmd(st, pud, addr);
437         }
438 }
439 
440 static void walk_pagetables(struct pg_state *st)
441 {
442         pgd_t *pgd = pgd_offset_k(0UL);
443         unsigned int i;
444         unsigned long addr;
445 
446         /*
447          * Traverse the linux pagetable structure and dump pages that are in
448          * the hash pagetable.
449          */
450         for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
451                 addr = KERN_VIRT_START + i * PGDIR_SIZE;
452                 if (!pgd_none(*pgd))
453                         /* pgd exists */
454                         walk_pud(st, pgd, addr);
455         }
456 }
457 
458 
459 static void walk_linearmapping(struct pg_state *st)
460 {
461         unsigned long addr;
462 
463         /*
464          * Traverse the linear mapping section of virtual memory and dump pages
465          * that are in the hash pagetable.
466          */
467         unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift;
468 
469         for (addr = PAGE_OFFSET; addr < PAGE_OFFSET +
470                         memblock_end_of_DRAM(); addr += psize)
471                 hpte_find(st, addr, mmu_linear_psize);
472 }
473 
474 static void walk_vmemmap(struct pg_state *st)
475 {
476 #ifdef CONFIG_SPARSEMEM_VMEMMAP
477         struct vmemmap_backing *ptr = vmemmap_list;
478 
479         /*
480          * Traverse the vmemmaped memory and dump pages that are in the hash
481          * pagetable.
482          */
483         while (ptr->list) {
484                 hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize);
485                 ptr = ptr->list;
486         }
487         seq_puts(st->seq, "---[ vmemmap end ]---\n");
488 #endif
489 }
490 
491 static void populate_markers(void)
492 {
493         address_markers[0].start_address = PAGE_OFFSET;
494         address_markers[1].start_address = VMALLOC_START;
495         address_markers[2].start_address = VMALLOC_END;
496         address_markers[3].start_address = ISA_IO_BASE;
497         address_markers[4].start_address = ISA_IO_END;
498         address_markers[5].start_address = PHB_IO_BASE;
499         address_markers[6].start_address = PHB_IO_END;
500         address_markers[7].start_address = IOREMAP_BASE;
501         address_markers[8].start_address = IOREMAP_END;
502 #ifdef CONFIG_PPC_BOOK3S_64
503         address_markers[9].start_address =  H_VMEMMAP_BASE;
504 #else
505         address_markers[9].start_address =  VMEMMAP_BASE;
506 #endif
507 }
508 
509 static int ptdump_show(struct seq_file *m, void *v)
510 {
511         struct pg_state st = {
512                 .seq = m,
513                 .start_address = PAGE_OFFSET,
514                 .marker = address_markers,
515         };
516         /*
517          * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and
518          * dump pages that are in the hash pagetable.
519          */
520         walk_linearmapping(&st);
521         walk_pagetables(&st);
522         walk_vmemmap(&st);
523         return 0;
524 }
525 
526 static int ptdump_open(struct inode *inode, struct file *file)
527 {
528         return single_open(file, ptdump_show, NULL);
529 }
530 
531 static const struct file_operations ptdump_fops = {
532         .open           = ptdump_open,
533         .read           = seq_read,
534         .llseek         = seq_lseek,
535         .release        = single_release,
536 };
537 
538 static int ptdump_init(void)
539 {
540         struct dentry *debugfs_file;
541 
542         if (!radix_enabled()) {
543                 populate_markers();
544                 debugfs_file = debugfs_create_file("kernel_hash_pagetable",
545                                 0400, NULL, NULL, &ptdump_fops);
546                 return debugfs_file ? 0 : -ENOMEM;
547         }
548         return 0;
549 }
550 device_initcall(ptdump_init);
551 

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