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 */ 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 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 * Get vmcoreinfo using lowcore->vmcore_info (new kernel) 229 */ 230 static 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(¬e, 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 */ 255 static 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 */ 271 static 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 */ 292 static 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 */ 307 static 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 */ 329 static inline unsigned long relocate(unsigned long addr) 330 { 331 return OLDMEM_BASE + addr; 332 } 333 334 /* 335 * Initialize ELF loads (new kernel) 336 */ 337 static 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 */ 368 static 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 */ 394 static 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 */ 429 static 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 } 441 442 subsys_initcall(setup_kdump_elfcorehdr); 443