LXR linux/arch/s390/kernel/crash

   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#include <asm/os_info.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 */
  30ssize_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 */
  55int 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 */
  72static 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 */
  85static 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 */
  98static 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 */
 122static 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 */
 141static 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 */
 156static 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 */
 165static 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 */
 174static 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 */
 183static 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 */
 192static 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 */
 201void *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 */
 216static 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 * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
 229 */
 230static void *get_vmcoreinfo_old(unsigned long *size)
 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 NULL;
 238        memset(nt_name, 0, sizeof(nt_name));
 239        if (copy_from_oldmem(&note, addr, sizeof(note)))
 240                return NULL;
 241        if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
 242                return NULL;
 243        if (strcmp(nt_name, "VMCOREINFO") != 0)
 244                return NULL;
 245        vmcoreinfo = kzalloc_panic(note.n_descsz);
 246        if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
 247                return NULL;
 248        *size = note.n_descsz;
 249        return vmcoreinfo;
 250}
 251
 252/*
 253 * Initialize vmcoreinfo note (new kernel)
 254 */
 255static void *nt_vmcoreinfo(void *ptr)
 256{
 257        unsigned long size;
 258        void *vmcoreinfo;
 259
 260        vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
 261        if (!vmcoreinfo)
 262                vmcoreinfo = get_vmcoreinfo_old(&size);
 263        if (!vmcoreinfo)
 264                return ptr;
 265        return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
 266}
 267
 268/*
 269 * Initialize ELF header (new kernel)
 270 */
 271static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
 272{
 273        memset(ehdr, 0, sizeof(*ehdr));
 274        memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 275        ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 276        ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
 277        ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 278        memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 279        ehdr->e_type = ET_CORE;
 280        ehdr->e_machine = EM_S390;
 281        ehdr->e_version = EV_CURRENT;
 282        ehdr->e_phoff = sizeof(Elf64_Ehdr);
 283        ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 284        ehdr->e_phentsize = sizeof(Elf64_Phdr);
 285        ehdr->e_phnum = mem_chunk_cnt + 1;
 286        return ehdr + 1;
 287}
 288
 289/*
 290 * Return CPU count for ELF header (new kernel)
 291 */
 292static int get_cpu_cnt(void)
 293{
 294        int i, cpus = 0;
 295
 296        for (i = 0; zfcpdump_save_areas[i]; i++) {
 297                if (zfcpdump_save_areas[i]->pref_reg == 0)
 298                        continue;
 299                cpus++;
 300        }
 301        return cpus;
 302}
 303
 304/*
 305 * Return memory chunk count for ELF header (new kernel)
 306 */
 307static int get_mem_chunk_cnt(void)
 308{
 309        struct mem_chunk *chunk_array, *mem_chunk;
 310        int i, cnt = 0;
 311
 312        chunk_array = get_memory_layout();
 313        for (i = 0; i < MEMORY_CHUNKS; i++) {
 314                mem_chunk = &chunk_array[i];
 315                if (chunk_array[i].type != CHUNK_READ_WRITE &&
 316                    chunk_array[i].type != CHUNK_READ_ONLY)
 317                        continue;
 318                if (mem_chunk->size == 0)
 319                        continue;
 320                cnt++;
 321        }
 322        kfree(chunk_array);
 323        return cnt;
 324}
 325
 326/*
 327 * Relocate pointer in order to allow vmcore code access the data
 328 */
 329static inline unsigned long relocate(unsigned long addr)
 330{
 331        return OLDMEM_BASE + addr;
 332}
 333
 334/*
 335 * Initialize ELF loads (new kernel)
 336 */
 337static int loads_init(Elf64_Phdr *phdr, u64 loads_offset)
 338{
 339        struct mem_chunk *chunk_array, *mem_chunk;
 340        int i;
 341
 342        chunk_array = get_memory_layout();
 343        for (i = 0; i < MEMORY_CHUNKS; i++) {
 344                mem_chunk = &chunk_array[i];
 345                if (mem_chunk->size == 0)
 346                        break;
 347                if (chunk_array[i].type != CHUNK_READ_WRITE &&
 348                    chunk_array[i].type != CHUNK_READ_ONLY)
 349                        continue;
 350                else
 351                        phdr->p_filesz = mem_chunk->size;
 352                phdr->p_type = PT_LOAD;
 353                phdr->p_offset = mem_chunk->addr;
 354                phdr->p_vaddr = mem_chunk->addr;
 355                phdr->p_paddr = mem_chunk->addr;
 356                phdr->p_memsz = mem_chunk->size;
 357                phdr->p_flags = PF_R | PF_W | PF_X;
 358                phdr->p_align = PAGE_SIZE;
 359                phdr++;
 360        }
 361        kfree(chunk_array);
 362        return i;
 363}
 364
 365/*
 366 * Initialize notes (new kernel)
 367 */
 368static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 369{
 370        struct save_area *sa;
 371        void *ptr_start = ptr;
 372        int i;
 373
 374        ptr = nt_prpsinfo(ptr);
 375
 376        for (i = 0; zfcpdump_save_areas[i]; i++) {
 377                sa = zfcpdump_save_areas[i];
 378                if (sa->pref_reg == 0)
 379                        continue;
 380                ptr = fill_cpu_elf_notes(ptr, sa);
 381        }
 382        ptr = nt_vmcoreinfo(ptr);
 383        memset(phdr, 0, sizeof(*phdr));
 384        phdr->p_type = PT_NOTE;
 385        phdr->p_offset = relocate(notes_offset);
 386        phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
 387        phdr->p_memsz = phdr->p_filesz;
 388        return ptr;
 389}
 390
 391/*
 392 * Create ELF core header (new kernel)
 393 */
 394static void s390_elf_corehdr_create(char **elfcorebuf, size_t *elfcorebuf_sz)
 395{
 396        Elf64_Phdr *phdr_notes, *phdr_loads;
 397        int mem_chunk_cnt;
 398        void *ptr, *hdr;
 399        u32 alloc_size;
 400        u64 hdr_off;
 401
 402        mem_chunk_cnt = get_mem_chunk_cnt();
 403
 404        alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +
 405                mem_chunk_cnt * sizeof(Elf64_Phdr);
 406        hdr = kzalloc_panic(alloc_size);
 407        /* Init elf header */
 408        ptr = ehdr_init(hdr, mem_chunk_cnt);
 409        /* Init program headers */
 410        phdr_notes = ptr;
 411        ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
 412        phdr_loads = ptr;
 413        ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
 414        /* Init notes */
 415        hdr_off = PTR_DIFF(ptr, hdr);
 416        ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
 417        /* Init loads */
 418        hdr_off = PTR_DIFF(ptr, hdr);
 419        loads_init(phdr_loads, ((unsigned long) hdr) + hdr_off);
 420        *elfcorebuf_sz = hdr_off;
 421        *elfcorebuf = (void *) relocate((unsigned long) hdr);
 422        BUG_ON(*elfcorebuf_sz > alloc_size);
 423}
 424
 425/*
 426 * Create kdump ELF core header in new kernel, if it has not been passed via
 427 * the "elfcorehdr" kernel parameter
 428 */
 429static int setup_kdump_elfcorehdr(void)
 430{
 431        size_t elfcorebuf_sz;
 432        char *elfcorebuf;
 433
 434        if (!OLDMEM_BASE || is_kdump_kernel())
 435                return -EINVAL;
 436        s390_elf_corehdr_create(&elfcorebuf, &elfcorebuf_sz);
 437        elfcorehdr_addr = (unsigned long long) elfcorebuf;
 438        elfcorehdr_size = elfcorebuf_sz;
 439        return 0;
 440}
 441
 442subsys_initcall(setup_kdump_elfcorehdr);
 443