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