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