arch/parisc/kernel/pdt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Page Deallocation Table (PDT) support
   4  *
   5  *    The Page Deallocation Table (PDT) is maintained by firmware and holds a
   6  *    list of memory addresses in which memory errors were detected.
   7  *    The list contains both single-bit (correctable) and double-bit
   8  *    (uncorrectable) errors.
   9  *
  10  *    Copyright 2017 by Helge Deller <deller@gmx.de>
  11  *
  12  *    possible future enhancements:
  13  *    - add userspace interface via procfs or sysfs to clear PDT
  14  */
  15
  16 #include <linux/memblock.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/kthread.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/initrd.h>
  21 #include <linux/pgtable.h>
  22 #include <linux/mm.h>
  23
  24 #include <asm/pdc.h>
  25 #include <asm/pdcpat.h>
  26 #include <asm/sections.h>
  27 #include <asm/pgtable.h>
  28
  29 enum pdt_access_type {
  30         PDT_NONE,
  31         PDT_PDC,
  32         PDT_PAT_NEW,
  33         PDT_PAT_CELL
  34 };
  35
  36 static enum pdt_access_type pdt_type;
  37
  38 /* PDT poll interval: 1 minute if errors, 5 minutes if everything OK. */
  39 #define PDT_POLL_INTERVAL_DEFAULT       (5*60*HZ)
  40 #define PDT_POLL_INTERVAL_SHORT         (1*60*HZ)
  41 static unsigned long pdt_poll_interval = PDT_POLL_INTERVAL_DEFAULT;
  42
  43 /* global PDT status information */
  44 static struct pdc_mem_retinfo pdt_status;
  45
  46 #define MAX_PDT_TABLE_SIZE      PAGE_SIZE
  47 #define MAX_PDT_ENTRIES         (MAX_PDT_TABLE_SIZE / sizeof(unsigned long))
  48 static unsigned long pdt_entry[MAX_PDT_ENTRIES] __page_aligned_bss;
  49
  50 /*
  51  * Constants for the pdt_entry format:
  52  * A pdt_entry holds the physical address in bits 0-57, bits 58-61 are
  53  * reserved, bit 62 is the perm bit and bit 63 is the error_type bit.
  54  * The perm bit indicates whether the error have been verified as a permanent
  55  * error (value of 1) or has not been verified, and may be transient (value
  56  * of 0). The error_type bit indicates whether the error is a single bit error
  57  * (value of 1) or a multiple bit error.
  58  * On non-PAT machines phys_addr is encoded in bits 0-59 and error_type in bit
  59  * 63. Those machines don't provide the perm bit.
  60  */
  61
  62 #define PDT_ADDR_PHYS_MASK      (pdt_type != PDT_PDC ? ~0x3f : ~0x0f)
  63 #define PDT_ADDR_PERM_ERR       (pdt_type != PDT_PDC ? 2UL : 0UL)
  64 #define PDT_ADDR_SINGLE_ERR     1UL
  65
  66 /* report PDT entries via /proc/meminfo */
  67 void arch_report_meminfo(struct seq_file *m)
  68 {
  69         if (pdt_type == PDT_NONE)
  70                 return;
  71
  72         seq_printf(m, "PDT_max_entries: %7lu\n",
  73                         pdt_status.pdt_size);
  74         seq_printf(m, "PDT_cur_entries: %7lu\n",
  75                         pdt_status.pdt_entries);
  76 }
  77
  78 static int get_info_pat_new(void)
  79 {
  80         struct pdc_pat_mem_retinfo pat_rinfo;
  81         int ret;
  82
  83         /* newer PAT machines like C8000 report info for all cells */
  84         if (is_pdc_pat())
  85                 ret = pdc_pat_mem_pdt_info(&pat_rinfo);
  86         else
  87                 return PDC_BAD_PROC;
  88
  89         pdt_status.pdt_size = pat_rinfo.max_pdt_entries;
  90         pdt_status.pdt_entries = pat_rinfo.current_pdt_entries;
  91         pdt_status.pdt_status = 0;
  92         pdt_status.first_dbe_loc = pat_rinfo.first_dbe_loc;
  93         pdt_status.good_mem = pat_rinfo.good_mem;
  94
  95         return ret;
  96 }
  97
  98 static int get_info_pat_cell(void)
  99 {
 100         struct pdc_pat_mem_cell_pdt_retinfo cell_rinfo;
 101         int ret;
 102
 103         /* older PAT machines like rp5470 report cell info only */
 104         if (is_pdc_pat())
 105                 ret = pdc_pat_mem_pdt_cell_info(&cell_rinfo, parisc_cell_num);
 106         else
 107                 return PDC_BAD_PROC;
 108
 109         pdt_status.pdt_size = cell_rinfo.max_pdt_entries;
 110         pdt_status.pdt_entries = cell_rinfo.current_pdt_entries;
 111         pdt_status.pdt_status = 0;
 112         pdt_status.first_dbe_loc = cell_rinfo.first_dbe_loc;
 113         pdt_status.good_mem = cell_rinfo.good_mem;
 114
 115         return ret;
 116 }
 117
 118 static void report_mem_err(unsigned long pde)
 119 {
 120         struct pdc_pat_mem_phys_mem_location loc;
 121         unsigned long addr;
 122         char dimm_txt[32];
 123
 124         addr = pde & PDT_ADDR_PHYS_MASK;
 125
 126         /* show DIMM slot description on PAT machines */
 127         if (is_pdc_pat()) {
 128                 pdc_pat_mem_get_dimm_phys_location(&loc, addr);
 129                 sprintf(dimm_txt, "DIMM slot %02x, ", loc.dimm_slot);
 130         } else
 131                 dimm_txt[0] = 0;
 132
 133         pr_warn("PDT: BAD MEMORY at 0x%08lx, %s%s%s-bit error.\n",
 134                 addr, dimm_txt,
 135                 pde & PDT_ADDR_PERM_ERR ? "permanent ":"",
 136                 pde & PDT_ADDR_SINGLE_ERR ? "single":"multi");
 137 }
 138
 139
 140 /*
 141  * pdc_pdt_init()
 142  *
 143  * Initialize kernel PDT structures, read initial PDT table from firmware,
 144  * report all current PDT entries and mark bad memory with memblock_reserve()
 145  * to avoid that the kernel will use broken memory areas.
 146  *
 147  */
 148 void __init pdc_pdt_init(void)
 149 {
 150         int ret, i;
 151         unsigned long entries;
 152         struct pdc_mem_read_pdt pdt_read_ret;
 153
 154         pdt_type = PDT_PAT_NEW;
 155         ret = get_info_pat_new();
 156
 157         if (ret != PDC_OK) {
 158                 pdt_type = PDT_PAT_CELL;
 159                 ret = get_info_pat_cell();
 160         }
 161
 162         if (ret != PDC_OK) {
 163                 pdt_type = PDT_PDC;
 164                 /* non-PAT machines provide the standard PDC call */
 165                 ret = pdc_mem_pdt_info(&pdt_status);
 166         }
 167
 168         if (ret != PDC_OK) {
 169                 pdt_type = PDT_NONE;
 170                 pr_info("PDT: Firmware does not provide any page deallocation"
 171                         " information.\n");
 172                 return;
 173         }
 174
 175         entries = pdt_status.pdt_entries;
 176         if (WARN_ON(entries > MAX_PDT_ENTRIES))
 177                 entries = pdt_status.pdt_entries = MAX_PDT_ENTRIES;
 178
 179         pr_info("PDT: type %s, size %lu, entries %lu, status %lu, dbe_loc 0x%lx,"
 180                 " good_mem %lu MB\n",
 181                         pdt_type == PDT_PDC ? __stringify(PDT_PDC) :
 182                         pdt_type == PDT_PAT_CELL ? __stringify(PDT_PAT_CELL)
 183                                                  : __stringify(PDT_PAT_NEW),
 184                         pdt_status.pdt_size, pdt_status.pdt_entries,
 185                         pdt_status.pdt_status, pdt_status.first_dbe_loc,
 186                         pdt_status.good_mem / 1024 / 1024);
 187
 188         if (entries == 0) {
 189                 pr_info("PDT: Firmware reports all memory OK.\n");
 190                 return;
 191         }
 192
 193         if (pdt_status.first_dbe_loc &&
 194                 pdt_status.first_dbe_loc <= __pa((unsigned long)&_end))
 195                 pr_crit("CRITICAL: Bad memory inside kernel image memory area!\n");
 196
 197         pr_warn("PDT: Firmware reports %lu entries of faulty memory:\n",
 198                 entries);
 199
 200         if (pdt_type == PDT_PDC)
 201                 ret = pdc_mem_pdt_read_entries(&pdt_read_ret, pdt_entry);
 202         else {
 203 #ifdef CONFIG_64BIT
 204                 struct pdc_pat_mem_read_pd_retinfo pat_pret;
 205
 206                 if (pdt_type == PDT_PAT_CELL)
 207                         ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
 208                                 MAX_PDT_ENTRIES);
 209                 else
 210                         ret = pdc_pat_mem_read_pd_pdt(&pat_pret, pdt_entry,
 211                                 MAX_PDT_TABLE_SIZE, 0);
 212 #else
 213                 ret = PDC_BAD_PROC;
 214 #endif
 215         }
 216
 217         if (ret != PDC_OK) {
 218                 pdt_type = PDT_NONE;
 219                 pr_warn("PDT: Get PDT entries failed with %d\n", ret);
 220                 return;
 221         }
 222
 223         for (i = 0; i < pdt_status.pdt_entries; i++) {
 224                 unsigned long addr;
 225
 226                 report_mem_err(pdt_entry[i]);
 227
 228                 addr = pdt_entry[i] & PDT_ADDR_PHYS_MASK;
 229                 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) &&
 230                         addr >= initrd_start && addr < initrd_end)
 231                         pr_crit("CRITICAL: initrd possibly broken "
 232                                 "due to bad memory!\n");
 233
 234                 /* mark memory page bad */
 235                 memblock_reserve(pdt_entry[i] & PAGE_MASK, PAGE_SIZE);
 236                 num_poisoned_pages_inc(addr >> PAGE_SHIFT);
 237         }
 238 }
 239
 240
 241 /*
 242  * This is the PDT kernel thread main loop.
 243  */
 244
 245 static int pdt_mainloop(void *unused)
 246 {
 247         struct pdc_mem_read_pdt pdt_read_ret;
 248         struct pdc_pat_mem_read_pd_retinfo pat_pret __maybe_unused;
 249         unsigned long old_num_entries;
 250         unsigned long *bad_mem_ptr;
 251         int num, ret;
 252
 253         for (;;) {
 254                 set_current_state(TASK_INTERRUPTIBLE);
 255
 256                 old_num_entries = pdt_status.pdt_entries;
 257
 258                 schedule_timeout(pdt_poll_interval);
 259                 if (kthread_should_stop())
 260                         break;
 261
 262                 /* Do we have new PDT entries? */
 263                 switch (pdt_type) {
 264                 case PDT_PAT_NEW:
 265                         ret = get_info_pat_new();
 266                         break;
 267                 case PDT_PAT_CELL:
 268                         ret = get_info_pat_cell();
 269                         break;
 270                 default:
 271                         ret = pdc_mem_pdt_info(&pdt_status);
 272                         break;
 273                 }
 274
 275                 if (ret != PDC_OK) {
 276                         pr_warn("PDT: unexpected failure %d\n", ret);
 277                         return -EINVAL;
 278                 }
 279
 280                 /* if no new PDT entries, just wait again */
 281                 num = pdt_status.pdt_entries - old_num_entries;
 282                 if (num <= 0)
 283                         continue;
 284
 285                 /* decrease poll interval in case we found memory errors */
 286                 if (pdt_status.pdt_entries &&
 287                         pdt_poll_interval == PDT_POLL_INTERVAL_DEFAULT)
 288                         pdt_poll_interval = PDT_POLL_INTERVAL_SHORT;
 289
 290                 /* limit entries to get */
 291                 if (num > MAX_PDT_ENTRIES) {
 292                         num = MAX_PDT_ENTRIES;
 293                         pdt_status.pdt_entries = old_num_entries + num;
 294                 }
 295
 296                 /* get new entries */
 297                 switch (pdt_type) {
 298 #ifdef CONFIG_64BIT
 299                 case PDT_PAT_CELL:
 300                         if (pdt_status.pdt_entries > MAX_PDT_ENTRIES) {
 301                                 pr_crit("PDT: too many entries.\n");
 302                                 return -ENOMEM;
 303                         }
 304                         ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
 305                                 MAX_PDT_ENTRIES);
 306                         bad_mem_ptr = &pdt_entry[old_num_entries];
 307                         break;
 308                 case PDT_PAT_NEW:
 309                         ret = pdc_pat_mem_read_pd_pdt(&pat_pret,
 310                                 pdt_entry,
 311                                 num * sizeof(unsigned long),
 312                                 old_num_entries * sizeof(unsigned long));
 313                         bad_mem_ptr = &pdt_entry[0];
 314                         break;
 315 #endif
 316                 default:
 317                         ret = pdc_mem_pdt_read_entries(&pdt_read_ret,
 318                                 pdt_entry);
 319                         bad_mem_ptr = &pdt_entry[old_num_entries];
 320                         break;
 321                 }
 322
 323                 /* report and mark memory broken */
 324                 while (num--) {
 325                         unsigned long pde = *bad_mem_ptr++;
 326
 327                         report_mem_err(pde);
 328
 329 #ifdef CONFIG_MEMORY_FAILURE
 330                         if ((pde & PDT_ADDR_PERM_ERR) ||
 331                             ((pde & PDT_ADDR_SINGLE_ERR) == 0))
 332                                 memory_failure(pde >> PAGE_SHIFT, 0);
 333                         else
 334                                 soft_offline_page(pde >> PAGE_SHIFT, 0);
 335 #else
 336                         pr_crit("PDT: memory error at 0x%lx ignored.\n"
 337                                 "Rebuild kernel with CONFIG_MEMORY_FAILURE=y "
 338                                 "for real handling.\n",
 339                                 pde & PDT_ADDR_PHYS_MASK);
 340 #endif
 341
 342                 }
 343         }
 344
 345         return 0;
 346 }
 347
 348
 349 static int __init pdt_initcall(void)
 350 {
 351         struct task_struct *kpdtd_task;
 352
 353         if (pdt_type == PDT_NONE)
 354                 return -ENODEV;
 355
 356         kpdtd_task = kthread_run(pdt_mainloop, NULL, "kpdtd");
 357
 358         return PTR_ERR_OR_ZERO(kpdtd_task);
 359 }
 360
 361 late_initcall(pdt_initcall);