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/initrd.h> 20 21 #include <asm/pdc.h> 22 #include <asm/pdcpat.h> 23 #include <asm/sections.h> 24 #include <asm/pgtable.h> 25 26 enum pdt_access_type { 27 PDT_NONE, 28 PDT_PDC, 29 PDT_PAT_NEW, 30 PDT_PAT_CELL 31 }; 32 33 static enum pdt_access_type pdt_type; 34 35 /* PDT poll interval: 1 minute if errors, 5 minutes if everything OK. */ 36 #define PDT_POLL_INTERVAL_DEFAULT (5*60*HZ) 37 #define PDT_POLL_INTERVAL_SHORT (1*60*HZ) 38 static unsigned long pdt_poll_interval = PDT_POLL_INTERVAL_DEFAULT; 39 40 /* global PDT status information */ 41 static struct pdc_mem_retinfo pdt_status; 42 43 #define MAX_PDT_TABLE_SIZE PAGE_SIZE 44 #define MAX_PDT_ENTRIES (MAX_PDT_TABLE_SIZE / sizeof(unsigned long)) 45 static unsigned long pdt_entry[MAX_PDT_ENTRIES] __page_aligned_bss; 46 47 /* 48 * Constants for the pdt_entry format: 49 * A pdt_entry holds the physical address in bits 0-57, bits 58-61 are 50 * reserved, bit 62 is the perm bit and bit 63 is the error_type bit. 51 * The perm bit indicates whether the error have been verified as a permanent 52 * error (value of 1) or has not been verified, and may be transient (value 53 * of 0). The error_type bit indicates whether the error is a single bit error 54 * (value of 1) or a multiple bit error. 55 * On non-PAT machines phys_addr is encoded in bits 0-59 and error_type in bit 56 * 63. Those machines don't provide the perm bit. 57 */ 58 59 #define PDT_ADDR_PHYS_MASK (pdt_type != PDT_PDC ? ~0x3f : ~0x0f) 60 #define PDT_ADDR_PERM_ERR (pdt_type != PDT_PDC ? 2UL : 0UL) 61 #define PDT_ADDR_SINGLE_ERR 1UL 62 63 /* report PDT entries via /proc/meminfo */ 64 void arch_report_meminfo(struct seq_file *m) 65 { 66 if (pdt_type == PDT_NONE) 67 return; 68 69 seq_printf(m, "PDT_max_entries: %7lu\n", 70 pdt_status.pdt_size); 71 seq_printf(m, "PDT_cur_entries: %7lu\n", 72 pdt_status.pdt_entries); 73 } 74 75 static int get_info_pat_new(void) 76 { 77 struct pdc_pat_mem_retinfo pat_rinfo; 78 int ret; 79 80 /* newer PAT machines like C8000 report info for all cells */ 81 if (is_pdc_pat()) 82 ret = pdc_pat_mem_pdt_info(&pat_rinfo); 83 else 84 return PDC_BAD_PROC; 85 86 pdt_status.pdt_size = pat_rinfo.max_pdt_entries; 87 pdt_status.pdt_entries = pat_rinfo.current_pdt_entries; 88 pdt_status.pdt_status = 0; 89 pdt_status.first_dbe_loc = pat_rinfo.first_dbe_loc; 90 pdt_status.good_mem = pat_rinfo.good_mem; 91 92 return ret; 93 } 94 95 static int get_info_pat_cell(void) 96 { 97 struct pdc_pat_mem_cell_pdt_retinfo cell_rinfo; 98 int ret; 99 100 /* older PAT machines like rp5470 report cell info only */ 101 if (is_pdc_pat()) 102 ret = pdc_pat_mem_pdt_cell_info(&cell_rinfo, parisc_cell_num); 103 else 104 return PDC_BAD_PROC; 105 106 pdt_status.pdt_size = cell_rinfo.max_pdt_entries; 107 pdt_status.pdt_entries = cell_rinfo.current_pdt_entries; 108 pdt_status.pdt_status = 0; 109 pdt_status.first_dbe_loc = cell_rinfo.first_dbe_loc; 110 pdt_status.good_mem = cell_rinfo.good_mem; 111 112 return ret; 113 } 114 115 static void report_mem_err(unsigned long pde) 116 { 117 struct pdc_pat_mem_phys_mem_location loc; 118 unsigned long addr; 119 char dimm_txt[32]; 120 121 addr = pde & PDT_ADDR_PHYS_MASK; 122 123 /* show DIMM slot description on PAT machines */ 124 if (is_pdc_pat()) { 125 pdc_pat_mem_get_dimm_phys_location(&loc, addr); 126 sprintf(dimm_txt, "DIMM slot %02x, ", loc.dimm_slot); 127 } else 128 dimm_txt[0] = 0; 129 130 pr_warn("PDT: BAD MEMORY at 0x%08lx, %s%s%s-bit error.\n", 131 addr, dimm_txt, 132 pde & PDT_ADDR_PERM_ERR ? "permanent ":"", 133 pde & PDT_ADDR_SINGLE_ERR ? "single":"multi"); 134 } 135 136 137 /* 138 * pdc_pdt_init() 139 * 140 * Initialize kernel PDT structures, read initial PDT table from firmware, 141 * report all current PDT entries and mark bad memory with memblock_reserve() 142 * to avoid that the kernel will use broken memory areas. 143 * 144 */ 145 void __init pdc_pdt_init(void) 146 { 147 int ret, i; 148 unsigned long entries; 149 struct pdc_mem_read_pdt pdt_read_ret; 150 151 pdt_type = PDT_PAT_NEW; 152 ret = get_info_pat_new(); 153 154 if (ret != PDC_OK) { 155 pdt_type = PDT_PAT_CELL; 156 ret = get_info_pat_cell(); 157 } 158 159 if (ret != PDC_OK) { 160 pdt_type = PDT_PDC; 161 /* non-PAT machines provide the standard PDC call */ 162 ret = pdc_mem_pdt_info(&pdt_status); 163 } 164 165 if (ret != PDC_OK) { 166 pdt_type = PDT_NONE; 167 pr_info("PDT: Firmware does not provide any page deallocation" 168 " information.\n"); 169 return; 170 } 171 172 entries = pdt_status.pdt_entries; 173 if (WARN_ON(entries > MAX_PDT_ENTRIES)) 174 entries = pdt_status.pdt_entries = MAX_PDT_ENTRIES; 175 176 pr_info("PDT: type %s, size %lu, entries %lu, status %lu, dbe_loc 0x%lx," 177 " good_mem %lu MB\n", 178 pdt_type == PDT_PDC ? __stringify(PDT_PDC) : 179 pdt_type == PDT_PAT_CELL ? __stringify(PDT_PAT_CELL) 180 : __stringify(PDT_PAT_NEW), 181 pdt_status.pdt_size, pdt_status.pdt_entries, 182 pdt_status.pdt_status, pdt_status.first_dbe_loc, 183 pdt_status.good_mem / 1024 / 1024); 184 185 if (entries == 0) { 186 pr_info("PDT: Firmware reports all memory OK.\n"); 187 return; 188 } 189 190 if (pdt_status.first_dbe_loc && 191 pdt_status.first_dbe_loc <= __pa((unsigned long)&_end)) 192 pr_crit("CRITICAL: Bad memory inside kernel image memory area!\n"); 193 194 pr_warn("PDT: Firmware reports %lu entries of faulty memory:\n", 195 entries); 196 197 if (pdt_type == PDT_PDC) 198 ret = pdc_mem_pdt_read_entries(&pdt_read_ret, pdt_entry); 199 else { 200 #ifdef CONFIG_64BIT 201 struct pdc_pat_mem_read_pd_retinfo pat_pret; 202 203 if (pdt_type == PDT_PAT_CELL) 204 ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry, 205 MAX_PDT_ENTRIES); 206 else 207 ret = pdc_pat_mem_read_pd_pdt(&pat_pret, pdt_entry, 208 MAX_PDT_TABLE_SIZE, 0); 209 #else 210 ret = PDC_BAD_PROC; 211 #endif 212 } 213 214 if (ret != PDC_OK) { 215 pdt_type = PDT_NONE; 216 pr_warn("PDT: Get PDT entries failed with %d\n", ret); 217 return; 218 } 219 220 for (i = 0; i < pdt_status.pdt_entries; i++) { 221 unsigned long addr; 222 223 report_mem_err(pdt_entry[i]); 224 225 addr = pdt_entry[i] & PDT_ADDR_PHYS_MASK; 226 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && 227 addr >= initrd_start && addr < initrd_end) 228 pr_crit("CRITICAL: initrd possibly broken " 229 "due to bad memory!\n"); 230 231 /* mark memory page bad */ 232 memblock_reserve(pdt_entry[i] & PAGE_MASK, PAGE_SIZE); 233 } 234 } 235 236 237 /* 238 * This is the PDT kernel thread main loop. 239 */ 240 241 static int pdt_mainloop(void *unused) 242 { 243 struct pdc_mem_read_pdt pdt_read_ret; 244 struct pdc_pat_mem_read_pd_retinfo pat_pret __maybe_unused; 245 unsigned long old_num_entries; 246 unsigned long *bad_mem_ptr; 247 int num, ret; 248 249 for (;;) { 250 set_current_state(TASK_INTERRUPTIBLE); 251 252 old_num_entries = pdt_status.pdt_entries; 253 254 schedule_timeout(pdt_poll_interval); 255 if (kthread_should_stop()) 256 break; 257 258 /* Do we have new PDT entries? */ 259 switch (pdt_type) { 260 case PDT_PAT_NEW: 261 ret = get_info_pat_new(); 262 break; 263 case PDT_PAT_CELL: 264 ret = get_info_pat_cell(); 265 break; 266 default: 267 ret = pdc_mem_pdt_info(&pdt_status); 268 break; 269 } 270 271 if (ret != PDC_OK) { 272 pr_warn("PDT: unexpected failure %d\n", ret); 273 return -EINVAL; 274 } 275 276 /* if no new PDT entries, just wait again */ 277 num = pdt_status.pdt_entries - old_num_entries; 278 if (num <= 0) 279 continue; 280 281 /* decrease poll interval in case we found memory errors */ 282 if (pdt_status.pdt_entries && 283 pdt_poll_interval == PDT_POLL_INTERVAL_DEFAULT) 284 pdt_poll_interval = PDT_POLL_INTERVAL_SHORT; 285 286 /* limit entries to get */ 287 if (num > MAX_PDT_ENTRIES) { 288 num = MAX_PDT_ENTRIES; 289 pdt_status.pdt_entries = old_num_entries + num; 290 } 291 292 /* get new entries */ 293 switch (pdt_type) { 294 #ifdef CONFIG_64BIT 295 case PDT_PAT_CELL: 296 if (pdt_status.pdt_entries > MAX_PDT_ENTRIES) { 297 pr_crit("PDT: too many entries.\n"); 298 return -ENOMEM; 299 } 300 ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry, 301 MAX_PDT_ENTRIES); 302 bad_mem_ptr = &pdt_entry[old_num_entries]; 303 break; 304 case PDT_PAT_NEW: 305 ret = pdc_pat_mem_read_pd_pdt(&pat_pret, 306 pdt_entry, 307 num * sizeof(unsigned long), 308 old_num_entries * sizeof(unsigned long)); 309 bad_mem_ptr = &pdt_entry[0]; 310 break; 311 #endif 312 default: 313 ret = pdc_mem_pdt_read_entries(&pdt_read_ret, 314 pdt_entry); 315 bad_mem_ptr = &pdt_entry[old_num_entries]; 316 break; 317 } 318 319 /* report and mark memory broken */ 320 while (num--) { 321 unsigned long pde = *bad_mem_ptr++; 322 323 report_mem_err(pde); 324 325 #ifdef CONFIG_MEMORY_FAILURE 326 if ((pde & PDT_ADDR_PERM_ERR) || 327 ((pde & PDT_ADDR_SINGLE_ERR) == 0)) 328 memory_failure(pde >> PAGE_SHIFT, 0); 329 else 330 soft_offline_page(pde >> PAGE_SHIFT, 0); 331 #else 332 pr_crit("PDT: memory error at 0x%lx ignored.\n" 333 "Rebuild kernel with CONFIG_MEMORY_FAILURE=y " 334 "for real handling.\n", 335 pde & PDT_ADDR_PHYS_MASK); 336 #endif 337 338 } 339 } 340 341 return 0; 342 } 343 344 345 static int __init pdt_initcall(void) 346 { 347 struct task_struct *kpdtd_task; 348 349 if (pdt_type == PDT_NONE) 350 return -ENODEV; 351 352 kpdtd_task = kthread_create(pdt_mainloop, NULL, "kpdtd"); 353 if (IS_ERR(kpdtd_task)) 354 return PTR_ERR(kpdtd_task); 355 356 wake_up_process(kpdtd_task); 357 358 return 0; 359 } 360 361 late_initcall(pdt_initcall); 362