arch/powerpc/mm/ptdump/hashpagetable.c

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