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   1 /*
   2  * Hypervisor-assisted dump
   3  *
   4  * Linas Vepstas, Manish Ahuja 2008
   5  * Copyright 2008 IBM Corp.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  *
  12  */
  13
  14 #include <linux/gfp.h>
  15 #include <linux/init.h>
  16 #include <linux/kobject.h>
  17 #include <linux/mm.h>
  18 #include <linux/of.h>
  19 #include <linux/pfn.h>
  20 #include <linux/swap.h>
  21 #include <linux/sysfs.h>
  22
  23 #include <asm/page.h>
  24 #include <asm/phyp_dump.h>
  25 #include <asm/machdep.h>
  26 #include <asm/prom.h>
  27 #include <asm/rtas.h>
  28
  29 /* Variables, used to communicate data between early boot and late boot */
  30 static struct phyp_dump phyp_dump_vars;
  31 struct phyp_dump *phyp_dump_info = &phyp_dump_vars;
  32
  33 static int ibm_configure_kernel_dump;
  34 /* ------------------------------------------------- */
  35 /* RTAS interfaces to declare the dump regions */
  36
  37 struct dump_section {
  38         u32 dump_flags;
  39         u16 source_type;
  40         u16 error_flags;
  41         u64 source_address;
  42         u64 source_length;
  43         u64 length_copied;
  44         u64 destination_address;
  45 };
  46
  47 struct phyp_dump_header {
  48         u32 version;
  49         u16 num_of_sections;
  50         u16 status;
  51
  52         u32 first_offset_section;
  53         u32 dump_disk_section;
  54         u64 block_num_dd;
  55         u64 num_of_blocks_dd;
  56         u32 offset_dd;
  57         u32 maxtime_to_auto;
  58         /* No dump disk path string used */
  59
  60         struct dump_section cpu_data;
  61         struct dump_section hpte_data;
  62         struct dump_section kernel_data;
  63 };
  64
  65 /* The dump header *must be* in low memory, so .bss it */
  66 static struct phyp_dump_header phdr;
  67
  68 #define NUM_DUMP_SECTIONS       3
  69 #define DUMP_HEADER_VERSION     0x1
  70 #define DUMP_REQUEST_FLAG       0x1
  71 #define DUMP_SOURCE_CPU         0x0001
  72 #define DUMP_SOURCE_HPTE        0x0002
  73 #define DUMP_SOURCE_RMO         0x0011
  74 #define DUMP_ERROR_FLAG         0x2000
  75 #define DUMP_TRIGGERED          0x4000
  76 #define DUMP_PERFORMED          0x8000
  77
  78
  79 /**
  80  * init_dump_header() - initialize the header declaring a dump
  81  * Returns: length of dump save area.
  82  *
  83  * When the hypervisor saves crashed state, it needs to put
  84  * it somewhere. The dump header tells the hypervisor where
  85  * the data can be saved.
  86  */
  87 static unsigned long init_dump_header(struct phyp_dump_header *ph)
  88 {
  89         unsigned long addr_offset = 0;
  90
  91         /* Set up the dump header */
  92         ph->version = DUMP_HEADER_VERSION;
  93         ph->num_of_sections = NUM_DUMP_SECTIONS;
  94         ph->status = 0;
  95
  96         ph->first_offset_section =
  97                 (u32)offsetof(struct phyp_dump_header, cpu_data);
  98         ph->dump_disk_section = 0;
  99         ph->block_num_dd = 0;
 100         ph->num_of_blocks_dd = 0;
 101         ph->offset_dd = 0;
 102
 103         ph->maxtime_to_auto = 0; /* disabled */
 104
 105         /* The first two sections are mandatory */
 106         ph->cpu_data.dump_flags = DUMP_REQUEST_FLAG;
 107         ph->cpu_data.source_type = DUMP_SOURCE_CPU;
 108         ph->cpu_data.source_address = 0;
 109         ph->cpu_data.source_length = phyp_dump_info->cpu_state_size;
 110         ph->cpu_data.destination_address = addr_offset;
 111         addr_offset += phyp_dump_info->cpu_state_size;
 112
 113         ph->hpte_data.dump_flags = DUMP_REQUEST_FLAG;
 114         ph->hpte_data.source_type = DUMP_SOURCE_HPTE;
 115         ph->hpte_data.source_address = 0;
 116         ph->hpte_data.source_length = phyp_dump_info->hpte_region_size;
 117         ph->hpte_data.destination_address = addr_offset;
 118         addr_offset += phyp_dump_info->hpte_region_size;
 119
 120         /* This section describes the low kernel region */
 121         ph->kernel_data.dump_flags = DUMP_REQUEST_FLAG;
 122         ph->kernel_data.source_type = DUMP_SOURCE_RMO;
 123         ph->kernel_data.source_address = PHYP_DUMP_RMR_START;
 124         ph->kernel_data.source_length = PHYP_DUMP_RMR_END;
 125         ph->kernel_data.destination_address = addr_offset;
 126         addr_offset += ph->kernel_data.source_length;
 127
 128         return addr_offset;
 129 }
 130
 131 static void print_dump_header(const struct phyp_dump_header *ph)
 132 {
 133 #ifdef DEBUG
 134         if (ph == NULL)
 135                 return;
 136
 137         printk(KERN_INFO "dump header:\n");
 138         /* setup some ph->sections required */
 139         printk(KERN_INFO "version = %d\n", ph->version);
 140         printk(KERN_INFO "Sections = %d\n", ph->num_of_sections);
 141         printk(KERN_INFO "Status = 0x%x\n", ph->status);
 142
 143         /* No ph->disk, so all should be set to 0 */
 144         printk(KERN_INFO "Offset to first section 0x%x\n",
 145                 ph->first_offset_section);
 146         printk(KERN_INFO "dump disk sections should be zero\n");
 147         printk(KERN_INFO "dump disk section = %d\n", ph->dump_disk_section);
 148         printk(KERN_INFO "block num = %lld\n", ph->block_num_dd);
 149         printk(KERN_INFO "number of blocks = %lld\n", ph->num_of_blocks_dd);
 150         printk(KERN_INFO "dump disk offset = %d\n", ph->offset_dd);
 151         printk(KERN_INFO "Max auto time= %d\n", ph->maxtime_to_auto);
 152
 153         /*set cpu state and hpte states as well scratch pad area */
 154         printk(KERN_INFO " CPU AREA\n");
 155         printk(KERN_INFO "cpu dump_flags =%d\n", ph->cpu_data.dump_flags);
 156         printk(KERN_INFO "cpu source_type =%d\n", ph->cpu_data.source_type);
 157         printk(KERN_INFO "cpu error_flags =%d\n", ph->cpu_data.error_flags);
 158         printk(KERN_INFO "cpu source_address =%llx\n",
 159                 ph->cpu_data.source_address);
 160         printk(KERN_INFO "cpu source_length =%llx\n",
 161                 ph->cpu_data.source_length);
 162         printk(KERN_INFO "cpu length_copied =%llx\n",
 163                 ph->cpu_data.length_copied);
 164
 165         printk(KERN_INFO " HPTE AREA\n");
 166         printk(KERN_INFO "HPTE dump_flags =%d\n", ph->hpte_data.dump_flags);
 167         printk(KERN_INFO "HPTE source_type =%d\n", ph->hpte_data.source_type);
 168         printk(KERN_INFO "HPTE error_flags =%d\n", ph->hpte_data.error_flags);
 169         printk(KERN_INFO "HPTE source_address =%llx\n",
 170                 ph->hpte_data.source_address);
 171         printk(KERN_INFO "HPTE source_length =%llx\n",
 172                 ph->hpte_data.source_length);
 173         printk(KERN_INFO "HPTE length_copied =%llx\n",
 174                 ph->hpte_data.length_copied);
 175
 176         printk(KERN_INFO " SRSD AREA\n");
 177         printk(KERN_INFO "SRSD dump_flags =%d\n", ph->kernel_data.dump_flags);
 178         printk(KERN_INFO "SRSD source_type =%d\n", ph->kernel_data.source_type);
 179         printk(KERN_INFO "SRSD error_flags =%d\n", ph->kernel_data.error_flags);
 180         printk(KERN_INFO "SRSD source_address =%llx\n",
 181                 ph->kernel_data.source_address);
 182         printk(KERN_INFO "SRSD source_length =%llx\n",
 183                 ph->kernel_data.source_length);
 184         printk(KERN_INFO "SRSD length_copied =%llx\n",
 185                 ph->kernel_data.length_copied);
 186 #endif
 187 }
 188
 189 static ssize_t show_phyp_dump_active(struct kobject *kobj,
 190                         struct kobj_attribute *attr, char *buf)
 191 {
 192
 193         /* create filesystem entry so kdump is phyp-dump aware */
 194         return sprintf(buf, "%lx\n", phyp_dump_info->phyp_dump_at_boot);
 195 }
 196
 197 static struct kobj_attribute pdl = __ATTR(phyp_dump_active, 0600,
 198                                         show_phyp_dump_active,
 199                                         NULL);
 200
 201 static void register_dump_area(struct phyp_dump_header *ph, unsigned long addr)
 202 {
 203         int rc;
 204
 205         /* Add addr value if not initialized before */
 206         if (ph->cpu_data.destination_address == 0) {
 207                 ph->cpu_data.destination_address += addr;
 208                 ph->hpte_data.destination_address += addr;
 209                 ph->kernel_data.destination_address += addr;
 210         }
 211
 212         /* ToDo Invalidate kdump and free memory range. */
 213
 214         do {
 215                 rc = rtas_call(ibm_configure_kernel_dump, 3, 1, NULL,
 216                                 1, ph, sizeof(struct phyp_dump_header));
 217         } while (rtas_busy_delay(rc));
 218
 219         if (rc) {
 220                 printk(KERN_ERR "phyp-dump: unexpected error (%d) on "
 221                                                 "register\n", rc);
 222                 print_dump_header(ph);
 223                 return;
 224         }
 225
 226         rc = sysfs_create_file(kernel_kobj, &pdl.attr);
 227         if (rc)
 228                 printk(KERN_ERR "phyp-dump: unable to create sysfs"
 229                                 " file (%d)\n", rc);
 230 }
 231
 232 static
 233 void invalidate_last_dump(struct phyp_dump_header *ph, unsigned long addr)
 234 {
 235         int rc;
 236
 237         /* Add addr value if not initialized before */
 238         if (ph->cpu_data.destination_address == 0) {
 239                 ph->cpu_data.destination_address += addr;
 240                 ph->hpte_data.destination_address += addr;
 241                 ph->kernel_data.destination_address += addr;
 242         }
 243
 244         do {
 245                 rc = rtas_call(ibm_configure_kernel_dump, 3, 1, NULL,
 246                                 2, ph, sizeof(struct phyp_dump_header));
 247         } while (rtas_busy_delay(rc));
 248
 249         if (rc) {
 250                 printk(KERN_ERR "phyp-dump: unexpected error (%d) "
 251                                                 "on invalidate\n", rc);
 252                 print_dump_header(ph);
 253         }
 254 }
 255
 256 /* ------------------------------------------------- */
 257 /**
 258  * release_memory_range -- release memory previously lmb_reserved
 259  * @start_pfn: starting physical frame number
 260  * @nr_pages: number of pages to free.
 261  *
 262  * This routine will release memory that had been previously
 263  * lmb_reserved in early boot. The released memory becomes
 264  * available for genreal use.
 265  */
 266 static void release_memory_range(unsigned long start_pfn,
 267                         unsigned long nr_pages)
 268 {
 269         struct page *rpage;
 270         unsigned long end_pfn;
 271         long i;
 272
 273         end_pfn = start_pfn + nr_pages;
 274
 275         for (i = start_pfn; i <= end_pfn; i++) {
 276                 rpage = pfn_to_page(i);
 277                 if (PageReserved(rpage)) {
 278                         ClearPageReserved(rpage);
 279                         init_page_count(rpage);
 280                         __free_page(rpage);
 281                         totalram_pages++;
 282                 }
 283         }
 284 }
 285
 286 /**
 287  * track_freed_range -- Counts the range being freed.
 288  * Once the counter goes to zero, it re-registers dump for
 289  * future use.
 290  */
 291 static void
 292 track_freed_range(unsigned long addr, unsigned long length)
 293 {
 294         static unsigned long scratch_area_size, reserved_area_size;
 295
 296         if (addr < phyp_dump_info->init_reserve_start)
 297                 return;
 298
 299         if ((addr >= phyp_dump_info->init_reserve_start) &&
 300             (addr <= phyp_dump_info->init_reserve_start +
 301              phyp_dump_info->init_reserve_size))
 302                 reserved_area_size += length;
 303
 304         if ((addr >= phyp_dump_info->reserved_scratch_addr) &&
 305             (addr <= phyp_dump_info->reserved_scratch_addr +
 306              phyp_dump_info->reserved_scratch_size))
 307                 scratch_area_size += length;
 308
 309         if ((reserved_area_size == phyp_dump_info->init_reserve_size) &&
 310             (scratch_area_size == phyp_dump_info->reserved_scratch_size)) {
 311
 312                 invalidate_last_dump(&phdr,
 313                                 phyp_dump_info->reserved_scratch_addr);
 314                 register_dump_area(&phdr,
 315                                 phyp_dump_info->reserved_scratch_addr);
 316         }
 317 }
 318
 319 /* ------------------------------------------------- */
 320 /**
 321  * sysfs_release_region -- sysfs interface to release memory range.
 322  *
 323  * Usage:
 324  *   "echo <start addr> <length> > /sys/kernel/release_region"
 325  *
 326  * Example:
 327  *   "echo 0x40000000 0x10000000 > /sys/kernel/release_region"
 328  *
 329  * will release 256MB starting at 1GB.
 330  */
 331 static ssize_t store_release_region(struct kobject *kobj,
 332                                 struct kobj_attribute *attr,
 333                                 const char *buf, size_t count)
 334 {
 335         unsigned long start_addr, length, end_addr;
 336         unsigned long start_pfn, nr_pages;
 337         ssize_t ret;
 338
 339         ret = sscanf(buf, "%lx %lx", &start_addr, &length);
 340         if (ret != 2)
 341                 return -EINVAL;
 342
 343         track_freed_range(start_addr, length);
 344
 345         /* Range-check - don't free any reserved memory that
 346          * wasn't reserved for phyp-dump */
 347         if (start_addr < phyp_dump_info->init_reserve_start)
 348                 start_addr = phyp_dump_info->init_reserve_start;
 349
 350         end_addr = phyp_dump_info->init_reserve_start +
 351                         phyp_dump_info->init_reserve_size;
 352         if (start_addr+length > end_addr)
 353                 length = end_addr - start_addr;
 354
 355         /* Release the region of memory assed in by user */
 356         start_pfn = PFN_DOWN(start_addr);
 357         nr_pages = PFN_DOWN(length);
 358         release_memory_range(start_pfn, nr_pages);
 359
 360         return count;
 361 }
 362
 363 static ssize_t show_release_region(struct kobject *kobj,
 364                         struct kobj_attribute *attr, char *buf)
 365 {
 366         u64 second_addr_range;
 367
 368         /* total reserved size - start of scratch area */
 369         second_addr_range = phyp_dump_info->init_reserve_size -
 370                                 phyp_dump_info->reserved_scratch_size;
 371         return sprintf(buf, "CPU:0x%llx-0x%llx: HPTE:0x%llx-0x%llx:"
 372                             " DUMP:0x%llx-0x%llx, 0x%lx-0x%llx:\n",
 373                 phdr.cpu_data.destination_address,
 374                 phdr.cpu_data.length_copied,
 375                 phdr.hpte_data.destination_address,
 376                 phdr.hpte_data.length_copied,
 377                 phdr.kernel_data.destination_address,
 378                 phdr.kernel_data.length_copied,
 379                 phyp_dump_info->init_reserve_start,
 380                 second_addr_range);
 381 }
 382
 383 static struct kobj_attribute rr = __ATTR(release_region, 0600,
 384                                         show_release_region,
 385                                         store_release_region);
 386
 387 static int __init phyp_dump_setup(void)
 388 {
 389         struct device_node *rtas;
 390         const struct phyp_dump_header *dump_header = NULL;
 391         unsigned long dump_area_start;
 392         unsigned long dump_area_length;
 393         int header_len = 0;
 394         int rc;
 395
 396         /* If no memory was reserved in early boot, there is nothing to do */
 397         if (phyp_dump_info->init_reserve_size == 0)
 398                 return 0;
 399
 400         /* Return if phyp dump not supported */
 401         if (!phyp_dump_info->phyp_dump_configured)
 402                 return -ENOSYS;
 403
 404         /* Is there dump data waiting for us? If there isn't,
 405          * then register a new dump area, and release all of
 406          * the rest of the reserved ram.
 407          *
 408          * The /rtas/ibm,kernel-dump rtas node is present only
 409          * if there is dump data waiting for us.
 410          */
 411         rtas = of_find_node_by_path("/rtas");
 412         if (rtas) {
 413                 dump_header = of_get_property(rtas, "ibm,kernel-dump",
 414                                                 &header_len);
 415                 of_node_put(rtas);
 416         }
 417
 418         ibm_configure_kernel_dump = rtas_token("ibm,configure-kernel-dump");
 419
 420         print_dump_header(dump_header);
 421         dump_area_length = init_dump_header(&phdr);
 422         /* align down */
 423         dump_area_start = phyp_dump_info->init_reserve_start & PAGE_MASK;
 424
 425         if (dump_header == NULL) {
 426                 register_dump_area(&phdr, dump_area_start);
 427                 return 0;
 428         }
 429
 430         /* re-register the dump area, if old dump was invalid */
 431         if ((dump_header) && (dump_header->status & DUMP_ERROR_FLAG)) {
 432                 invalidate_last_dump(&phdr, dump_area_start);
 433                 register_dump_area(&phdr, dump_area_start);
 434                 return 0;
 435         }
 436
 437         if (dump_header) {
 438                 phyp_dump_info->reserved_scratch_addr =
 439                                 dump_header->cpu_data.destination_address;
 440                 phyp_dump_info->reserved_scratch_size =
 441                                 dump_header->cpu_data.source_length +
 442                                 dump_header->hpte_data.source_length +
 443                                 dump_header->kernel_data.source_length;
 444         }
 445
 446         /* Should we create a dump_subsys, analogous to s390/ipl.c ? */
 447         rc = sysfs_create_file(kernel_kobj, &rr.attr);
 448         if (rc)
 449                 printk(KERN_ERR "phyp-dump: unable to create sysfs file (%d)\n",
 450                                                                         rc);
 451
 452         /* ToDo: re-register the dump area, for next time. */
 453         return 0;
 454 }
 455 machine_subsys_initcall(pseries, phyp_dump_setup);
 456
 457 int __init early_init_dt_scan_phyp_dump(unsigned long node,
 458                 const char *uname, int depth, void *data)
 459 {
 460         const unsigned int *sizes;
 461
 462         phyp_dump_info->phyp_dump_configured = 0;
 463         phyp_dump_info->phyp_dump_is_active = 0;
 464
 465         if (depth != 1 || strcmp(uname, "rtas") != 0)
 466                 return 0;
 467
 468         if (of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL))
 469                 phyp_dump_info->phyp_dump_configured++;
 470
 471         if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
 472                 phyp_dump_info->phyp_dump_is_active++;
 473
 474         sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
 475                                     NULL);
 476         if (!sizes)
 477                 return 0;
 478
 479         if (sizes[0] == 1)
 480                 phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
 481
 482         if (sizes[3] == 2)
 483                 phyp_dump_info->hpte_region_size =
 484                                                 *((unsigned long *)&sizes[4]);
 485         return 1;
 486 }
 487
 488 /* Look for phyp_dump= cmdline option */
 489 static int __init early_phyp_dump_enabled(char *p)
 490 {
 491         phyp_dump_info->phyp_dump_at_boot = 1;
 492
 493         if (!p)
 494                 return 0;
 495
 496         if (strncmp(p, "1", 1) == 0)
 497                 phyp_dump_info->phyp_dump_at_boot = 1;
 498         else if (strncmp(p, "0", 1) == 0)
 499                 phyp_dump_info->phyp_dump_at_boot = 0;
 500
 501         return 0;
 502 }
 503 early_param("phyp_dump", early_phyp_dump_enabled);
 504
 505 /* Look for phyp_dump_reserve_size= cmdline option */
 506 static int __init early_phyp_dump_reserve_size(char *p)
 507 {
 508         if (p)
 509                 phyp_dump_info->reserve_bootvar = memparse(p, &p);
 510
 511         return 0;
 512 }
 513 early_param("phyp_dump_reserve_size", early_phyp_dump_reserve_size);