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(¬e, 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); 426