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/os_info.h> 17 #include <asm/elf.h> 18 #include <asm/ipl.h> 19 20 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y))) 21 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y))) 22 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y)))) 23 24 /* 25 * Copy one page from "oldmem" 26 * 27 * For the kdump reserved memory this functions performs a swap operation: 28 * - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE]. 29 * - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] 30 */ 31 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, 32 size_t csize, unsigned long offset, int userbuf) 33 { 34 unsigned long src; 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 copy_to_user_real((void __force __user *) buf, (void *) src, 47 csize); 48 else 49 memcpy_real(buf, (void *) src, csize); 50 return csize; 51 } 52 53 /* 54 * Copy memory from old kernel 55 */ 56 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 * Get vmcoreinfo using lowcore->vmcore_info (new kernel) 230 */ 231 static void *get_vmcoreinfo_old(unsigned long *size) 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 NULL; 239 memset(nt_name, 0, sizeof(nt_name)); 240 if (copy_from_oldmem(¬e, addr, sizeof(note))) 241 return NULL; 242 if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1)) 243 return NULL; 244 if (strcmp(nt_name, "VMCOREINFO") != 0) 245 return NULL; 246 vmcoreinfo = kzalloc_panic(note.n_descsz); 247 if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz)) 248 return NULL; 249 *size = note.n_descsz; 250 return vmcoreinfo; 251 } 252 253 /* 254 * Initialize vmcoreinfo note (new kernel) 255 */ 256 static void *nt_vmcoreinfo(void *ptr) 257 { 258 unsigned long size; 259 void *vmcoreinfo; 260 261 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size); 262 if (!vmcoreinfo) 263 vmcoreinfo = get_vmcoreinfo_old(&size); 264 if (!vmcoreinfo) 265 return ptr; 266 return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO"); 267 } 268 269 /* 270 * Initialize ELF header (new kernel) 271 */ 272 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt) 273 { 274 memset(ehdr, 0, sizeof(*ehdr)); 275 memcpy(ehdr->e_ident, ELFMAG, SELFMAG); 276 ehdr->e_ident[EI_CLASS] = ELFCLASS64; 277 ehdr->e_ident[EI_DATA] = ELFDATA2MSB; 278 ehdr->e_ident[EI_VERSION] = EV_CURRENT; 279 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); 280 ehdr->e_type = ET_CORE; 281 ehdr->e_machine = EM_S390; 282 ehdr->e_version = EV_CURRENT; 283 ehdr->e_phoff = sizeof(Elf64_Ehdr); 284 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 285 ehdr->e_phentsize = sizeof(Elf64_Phdr); 286 ehdr->e_phnum = mem_chunk_cnt + 1; 287 return ehdr + 1; 288 } 289 290 /* 291 * Return CPU count for ELF header (new kernel) 292 */ 293 static int get_cpu_cnt(void) 294 { 295 int i, cpus = 0; 296 297 for (i = 0; zfcpdump_save_areas[i]; i++) { 298 if (zfcpdump_save_areas[i]->pref_reg == 0) 299 continue; 300 cpus++; 301 } 302 return cpus; 303 } 304 305 /* 306 * Return memory chunk count for ELF header (new kernel) 307 */ 308 static int get_mem_chunk_cnt(void) 309 { 310 struct mem_chunk *chunk_array, *mem_chunk; 311 int i, cnt = 0; 312 313 chunk_array = get_memory_layout(); 314 for (i = 0; i < MEMORY_CHUNKS; i++) { 315 mem_chunk = &chunk_array[i]; 316 if (chunk_array[i].type != CHUNK_READ_WRITE && 317 chunk_array[i].type != CHUNK_READ_ONLY) 318 continue; 319 if (mem_chunk->size == 0) 320 continue; 321 cnt++; 322 } 323 kfree(chunk_array); 324 return cnt; 325 } 326 327 /* 328 * Relocate pointer in order to allow vmcore code access the data 329 */ 330 static inline unsigned long relocate(unsigned long addr) 331 { 332 return OLDMEM_BASE + addr; 333 } 334 335 /* 336 * Initialize ELF loads (new kernel) 337 */ 338 static int loads_init(Elf64_Phdr *phdr, u64 loads_offset) 339 { 340 struct mem_chunk *chunk_array, *mem_chunk; 341 int i; 342 343 chunk_array = get_memory_layout(); 344 for (i = 0; i < MEMORY_CHUNKS; i++) { 345 mem_chunk = &chunk_array[i]; 346 if (mem_chunk->size == 0) 347 break; 348 if (chunk_array[i].type != CHUNK_READ_WRITE && 349 chunk_array[i].type != CHUNK_READ_ONLY) 350 continue; 351 else 352 phdr->p_filesz = mem_chunk->size; 353 phdr->p_type = PT_LOAD; 354 phdr->p_offset = mem_chunk->addr; 355 phdr->p_vaddr = mem_chunk->addr; 356 phdr->p_paddr = mem_chunk->addr; 357 phdr->p_memsz = mem_chunk->size; 358 phdr->p_flags = PF_R | PF_W | PF_X; 359 phdr->p_align = PAGE_SIZE; 360 phdr++; 361 } 362 kfree(chunk_array); 363 return i; 364 } 365 366 /* 367 * Initialize notes (new kernel) 368 */ 369 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset) 370 { 371 struct save_area *sa; 372 void *ptr_start = ptr; 373 int i; 374 375 ptr = nt_prpsinfo(ptr); 376 377 for (i = 0; zfcpdump_save_areas[i]; i++) { 378 sa = zfcpdump_save_areas[i]; 379 if (sa->pref_reg == 0) 380 continue; 381 ptr = fill_cpu_elf_notes(ptr, sa); 382 } 383 ptr = nt_vmcoreinfo(ptr); 384 memset(phdr, 0, sizeof(*phdr)); 385 phdr->p_type = PT_NOTE; 386 phdr->p_offset = relocate(notes_offset); 387 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start); 388 phdr->p_memsz = phdr->p_filesz; 389 return ptr; 390 } 391 392 /* 393 * Create ELF core header (new kernel) 394 */ 395 static void s390_elf_corehdr_create(char **elfcorebuf, size_t *elfcorebuf_sz) 396 { 397 Elf64_Phdr *phdr_notes, *phdr_loads; 398 int mem_chunk_cnt; 399 void *ptr, *hdr; 400 u32 alloc_size; 401 u64 hdr_off; 402 403 mem_chunk_cnt = get_mem_chunk_cnt(); 404 405 alloc_size = 0x1000 + get_cpu_cnt() * 0x300 + 406 mem_chunk_cnt * sizeof(Elf64_Phdr); 407 hdr = kzalloc_panic(alloc_size); 408 /* Init elf header */ 409 ptr = ehdr_init(hdr, mem_chunk_cnt); 410 /* Init program headers */ 411 phdr_notes = ptr; 412 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr)); 413 phdr_loads = ptr; 414 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt); 415 /* Init notes */ 416 hdr_off = PTR_DIFF(ptr, hdr); 417 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off); 418 /* Init loads */ 419 hdr_off = PTR_DIFF(ptr, hdr); 420 loads_init(phdr_loads, ((unsigned long) hdr) + hdr_off); 421 *elfcorebuf_sz = hdr_off; 422 *elfcorebuf = (void *) relocate((unsigned long) hdr); 423 BUG_ON(*elfcorebuf_sz > alloc_size); 424 } 425 426 /* 427 * Create kdump ELF core header in new kernel, if it has not been passed via 428 * the "elfcorehdr" kernel parameter 429 */ 430 static int setup_kdump_elfcorehdr(void) 431 { 432 size_t elfcorebuf_sz; 433 char *elfcorebuf; 434 435 if (!OLDMEM_BASE || is_kdump_kernel()) 436 return -EINVAL; 437 s390_elf_corehdr_create(&elfcorebuf, &elfcorebuf_sz); 438 elfcorehdr_addr = (unsigned long long) elfcorebuf; 439 elfcorehdr_size = elfcorebuf_sz; 440 return 0; 441 } 442 443 subsys_initcall(setup_kdump_elfcorehdr); 444