arch/s390/kernel/crash_dump.c

   1 /*
   2  * S390 kdump implementation
   3  *
   4  * Copyright IBM Corp. 2011
   5  * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
   6  */
   7
   8 #include <linux/crash_dump.h>
   9 #include <asm/lowcore.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/gfp.h>
  13 #include <linux/slab.h>
  14 #include <linux/crash_dump.h>
  15 #include <linux/bootmem.h>
  16 #include <linux/elf.h>
  17 #include <asm/ipl.h>
  18
  19 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
  20 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
  21 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
  22
  23 /*
  24  * Copy one page from "oldmem"
  25  *
  26  * For the kdump reserved memory this functions performs a swap operation:
  27  *  - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
  28  *  - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
  29  */
  30 ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
  31                          size_t csize, unsigned long offset, int userbuf)
  32 {
  33         unsigned long src;
  34         int rc;
  35
  36         if (!csize)
  37                 return 0;
  38
  39         src = (pfn << PAGE_SHIFT) + offset;
  40         if (src < OLDMEM_SIZE)
  41                 src += OLDMEM_BASE;
  42         else if (src > OLDMEM_BASE &&
  43                  src < OLDMEM_BASE + OLDMEM_SIZE)
  44                 src -= OLDMEM_BASE;
  45         if (userbuf)
  46                 rc = copy_to_user_real((void __user *) buf, (void *) src,
  47                                        csize);
  48         else
  49                 rc = memcpy_real(buf, (void *) src, csize);
  50         return rc < 0 ? rc : csize;
  51 }
  52
  53 /*
  54  * Copy memory from old kernel
  55  */
  56 static int copy_from_oldmem(void *dest, void *src, size_t count)
  57 {
  58         unsigned long copied = 0;
  59         int rc;
  60
  61         if ((unsigned long) src < OLDMEM_SIZE) {
  62                 copied = min(count, OLDMEM_SIZE - (unsigned long) src);
  63                 rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
  64                 if (rc)
  65                         return rc;
  66         }
  67         return memcpy_real(dest + copied, src + copied, count - copied);
  68 }
  69
  70 /*
  71  * Alloc memory and panic in case of ENOMEM
  72  */
  73 static void *kzalloc_panic(int len)
  74 {
  75         void *rc;
  76
  77         rc = kzalloc(len, GFP_KERNEL);
  78         if (!rc)
  79                 panic("s390 kdump kzalloc (%d) failed", len);
  80         return rc;
  81 }
  82
  83 /*
  84  * Get memory layout and create hole for oldmem
  85  */
  86 static struct mem_chunk *get_memory_layout(void)
  87 {
  88         struct mem_chunk *chunk_array;
  89
  90         chunk_array = kzalloc_panic(MEMORY_CHUNKS * sizeof(struct mem_chunk));
  91         detect_memory_layout(chunk_array);
  92         create_mem_hole(chunk_array, OLDMEM_BASE, OLDMEM_SIZE, CHUNK_CRASHK);
  93         return chunk_array;
  94 }
  95
  96 /*
  97  * Initialize ELF note
  98  */
  99 static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
 100                      const char *name)
 101 {
 102         Elf64_Nhdr *note;
 103         u64 len;
 104
 105         note = (Elf64_Nhdr *)buf;
 106         note->n_namesz = strlen(name) + 1;
 107         note->n_descsz = d_len;
 108         note->n_type = type;
 109         len = sizeof(Elf64_Nhdr);
 110
 111         memcpy(buf + len, name, note->n_namesz);
 112         len = roundup(len + note->n_namesz, 4);
 113
 114         memcpy(buf + len, desc, note->n_descsz);
 115         len = roundup(len + note->n_descsz, 4);
 116
 117         return PTR_ADD(buf, len);
 118 }
 119
 120 /*
 121  * Initialize prstatus note
 122  */
 123 static void *nt_prstatus(void *ptr, struct save_area *sa)
 124 {
 125         struct elf_prstatus nt_prstatus;
 126         static int cpu_nr = 1;
 127
 128         memset(&nt_prstatus, 0, sizeof(nt_prstatus));
 129         memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
 130         memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
 131         memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
 132         nt_prstatus.pr_pid = cpu_nr;
 133         cpu_nr++;
 134
 135         return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
 136                          "CORE");
 137 }
 138
 139 /*
 140  * Initialize fpregset (floating point) note
 141  */
 142 static void *nt_fpregset(void *ptr, struct save_area *sa)
 143 {
 144         elf_fpregset_t nt_fpregset;
 145
 146         memset(&nt_fpregset, 0, sizeof(nt_fpregset));
 147         memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
 148         memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));
 149
 150         return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
 151                        "CORE");
 152 }
 153
 154 /*
 155  * Initialize timer note
 156  */
 157 static void *nt_s390_timer(void *ptr, struct save_area *sa)
 158 {
 159         return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
 160                          KEXEC_CORE_NOTE_NAME);
 161 }
 162
 163 /*
 164  * Initialize TOD clock comparator note
 165  */
 166 static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
 167 {
 168         return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
 169                        sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
 170 }
 171
 172 /*
 173  * Initialize TOD programmable register note
 174  */
 175 static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
 176 {
 177         return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
 178                        sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
 179 }
 180
 181 /*
 182  * Initialize control register note
 183  */
 184 static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
 185 {
 186         return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
 187                        sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
 188 }
 189
 190 /*
 191  * Initialize prefix register note
 192  */
 193 static void *nt_s390_prefix(void *ptr, struct save_area *sa)
 194 {
 195         return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
 196                          sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
 197 }
 198
 199 /*
 200  * Fill ELF notes for one CPU with save area registers
 201  */
 202 void *fill_cpu_elf_notes(void *ptr, struct save_area *sa)
 203 {
 204         ptr = nt_prstatus(ptr, sa);
 205         ptr = nt_fpregset(ptr, sa);
 206         ptr = nt_s390_timer(ptr, sa);
 207         ptr = nt_s390_tod_cmp(ptr, sa);
 208         ptr = nt_s390_tod_preg(ptr, sa);
 209         ptr = nt_s390_ctrs(ptr, sa);
 210         ptr = nt_s390_prefix(ptr, sa);
 211         return ptr;
 212 }
 213
 214 /*
 215  * Initialize prpsinfo note (new kernel)
 216  */
 217 static void *nt_prpsinfo(void *ptr)
 218 {
 219         struct elf_prpsinfo prpsinfo;
 220
 221         memset(&prpsinfo, 0, sizeof(prpsinfo));
 222         prpsinfo.pr_sname = 'R';
 223         strcpy(prpsinfo.pr_fname, "vmlinux");
 224         return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo),
 225                        KEXEC_CORE_NOTE_NAME);
 226 }
 227
 228 /*
 229  * Initialize vmcoreinfo note (new kernel)
 230  */
 231 static void *nt_vmcoreinfo(void *ptr)
 232 {
 233         char nt_name[11], *vmcoreinfo;
 234         Elf64_Nhdr note;
 235         void *addr;
 236
 237         if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
 238                 return ptr;
 239         memset(nt_name, 0, sizeof(nt_name));
 240         if (copy_from_oldmem(&note, addr, sizeof(note)))
 241                 return ptr;
 242         if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
 243                 return ptr;
 244         if (strcmp(nt_name, "VMCOREINFO") != 0)
 245                 return ptr;
 246         vmcoreinfo = kzalloc_panic(note.n_descsz + 1);
 247         if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
 248                 return ptr;
 249         vmcoreinfo[note.n_descsz + 1] = 0;
 250         return nt_init(ptr, 0, vmcoreinfo, note.n_descsz, "VMCOREINFO");
 251 }
 252
 253 /*
 254  * Initialize ELF header (new kernel)
 255  */
 256 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
 257 {
 258         memset(ehdr, 0, sizeof(*ehdr));
 259         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 260         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 261         ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
 262         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 263         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 264         ehdr->e_type = ET_CORE;
 265         ehdr->e_machine = EM_S390;
 266         ehdr->e_version = EV_CURRENT;
 267         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 268         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 269         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 270         ehdr->e_phnum = mem_chunk_cnt + 1;
 271         return ehdr + 1;
 272 }
 273
 274 /*
 275  * Return CPU count for ELF header (new kernel)
 276  */
 277 static int get_cpu_cnt(void)
 278 {
 279         int i, cpus = 0;
 280
 281         for (i = 0; zfcpdump_save_areas[i]; i++) {
 282                 if (zfcpdump_save_areas[i]->pref_reg == 0)
 283                         continue;
 284                 cpus++;
 285         }
 286         return cpus;
 287 }
 288
 289 /*
 290  * Return memory chunk count for ELF header (new kernel)
 291  */
 292 static int get_mem_chunk_cnt(void)
 293 {
 294         struct mem_chunk *chunk_array, *mem_chunk;
 295         int i, cnt = 0;
 296
 297         chunk_array = get_memory_layout();
 298         for (i = 0; i < MEMORY_CHUNKS; i++) {
 299                 mem_chunk = &chunk_array[i];
 300                 if (chunk_array[i].type != CHUNK_READ_WRITE &&
 301                     chunk_array[i].type != CHUNK_READ_ONLY)
 302                         continue;
 303                 if (mem_chunk->size == 0)
 304                         continue;
 305                 cnt++;
 306         }
 307         kfree(chunk_array);
 308         return cnt;
 309 }
 310
 311 /*
 312  * Relocate pointer in order to allow vmcore code access the data
 313  */
 314 static inline unsigned long relocate(unsigned long addr)
 315 {
 316         return OLDMEM_BASE + addr;
 317 }
 318
 319 /*
 320  * Initialize ELF loads (new kernel)
 321  */
 322 static int loads_init(Elf64_Phdr *phdr, u64 loads_offset)
 323 {
 324         struct mem_chunk *chunk_array, *mem_chunk;
 325         int i;
 326
 327         chunk_array = get_memory_layout();
 328         for (i = 0; i < MEMORY_CHUNKS; i++) {
 329                 mem_chunk = &chunk_array[i];
 330                 if (mem_chunk->size == 0)
 331                         break;
 332                 if (chunk_array[i].type != CHUNK_READ_WRITE &&
 333                     chunk_array[i].type != CHUNK_READ_ONLY)
 334                         continue;
 335                 else
 336                         phdr->p_filesz = mem_chunk->size;
 337                 phdr->p_type = PT_LOAD;
 338                 phdr->p_offset = mem_chunk->addr;
 339                 phdr->p_vaddr = mem_chunk->addr;
 340                 phdr->p_paddr = mem_chunk->addr;
 341                 phdr->p_memsz = mem_chunk->size;
 342                 phdr->p_flags = PF_R | PF_W | PF_X;
 343                 phdr->p_align = PAGE_SIZE;
 344                 phdr++;
 345         }
 346         kfree(chunk_array);
 347         return i;
 348 }
 349
 350 /*
 351  * Initialize notes (new kernel)
 352  */
 353 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 354 {
 355         struct save_area *sa;
 356         void *ptr_start = ptr;
 357         int i;
 358
 359         ptr = nt_prpsinfo(ptr);
 360
 361         for (i = 0; zfcpdump_save_areas[i]; i++) {
 362                 sa = zfcpdump_save_areas[i];
 363                 if (sa->pref_reg == 0)
 364                         continue;
 365                 ptr = fill_cpu_elf_notes(ptr, sa);
 366         }
 367         ptr = nt_vmcoreinfo(ptr);
 368         memset(phdr, 0, sizeof(*phdr));
 369         phdr->p_type = PT_NOTE;
 370         phdr->p_offset = relocate(notes_offset);
 371         phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
 372         phdr->p_memsz = phdr->p_filesz;
 373         return ptr;
 374 }
 375
 376 /*
 377  * Create ELF core header (new kernel)
 378  */
 379 static void s390_elf_corehdr_create(char **elfcorebuf, size_t *elfcorebuf_sz)
 380 {
 381         Elf64_Phdr *phdr_notes, *phdr_loads;
 382         int mem_chunk_cnt;
 383         void *ptr, *hdr;
 384         u32 alloc_size;
 385         u64 hdr_off;
 386
 387         mem_chunk_cnt = get_mem_chunk_cnt();
 388
 389         alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +
 390                 mem_chunk_cnt * sizeof(Elf64_Phdr);
 391         hdr = kzalloc_panic(alloc_size);
 392         /* Init elf header */
 393         ptr = ehdr_init(hdr, mem_chunk_cnt);
 394         /* Init program headers */
 395         phdr_notes = ptr;
 396         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
 397         phdr_loads = ptr;
 398         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
 399         /* Init notes */
 400         hdr_off = PTR_DIFF(ptr, hdr);
 401         ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
 402         /* Init loads */
 403         hdr_off = PTR_DIFF(ptr, hdr);
 404         loads_init(phdr_loads, ((unsigned long) hdr) + hdr_off);
 405         *elfcorebuf_sz = hdr_off;
 406         *elfcorebuf = (void *) relocate((unsigned long) hdr);
 407         BUG_ON(*elfcorebuf_sz > alloc_size);
 408 }
 409
 410 /*
 411  * Create kdump ELF core header in new kernel, if it has not been passed via
 412  * the "elfcorehdr" kernel parameter
 413  */
 414 static int setup_kdump_elfcorehdr(void)
 415 {
 416         size_t elfcorebuf_sz;
 417         char *elfcorebuf;
 418
 419         if (!OLDMEM_BASE || is_kdump_kernel())
 420                 return -EINVAL;
 421         s390_elf_corehdr_create(&elfcorebuf, &elfcorebuf_sz);
 422         elfcorehdr_addr = (unsigned long long) elfcorebuf;
 423         elfcorehdr_size = elfcorebuf_sz;
 424         return 0;
 425 }
 426
 427 subsys_initcall(setup_kdump_elfcorehdr);