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(¬e, 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); 427