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