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 <linux/memblock.h> 17 #include <asm/os_info.h> 18 #include <asm/elf.h> 19 #include <asm/ipl.h> 20 #include <asm/sclp.h> 21 22 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y))) 23 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y))) 24 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y)))) 25 26 static struct memblock_region oldmem_region; 27 28 static struct memblock_type oldmem_type = { 29 .cnt = 1, 30 .max = 1, 31 .total_size = 0, 32 .regions = &oldmem_region, 33 }; 34 35 #define for_each_dump_mem_range(i, nid, p_start, p_end, p_nid) \ 36 for (i = 0, __next_mem_range(&i, nid, MEMBLOCK_NONE, \ 37 &memblock.physmem, \ 38 &oldmem_type, p_start, \ 39 p_end, p_nid); \ 40 i != (u64)ULLONG_MAX; \ 41 __next_mem_range(&i, nid, MEMBLOCK_NONE, &memblock.physmem,\ 42 &oldmem_type, \ 43 p_start, p_end, p_nid)) 44 45 struct dump_save_areas dump_save_areas; 46 47 /* 48 * Allocate and add a save area for a CPU 49 */ 50 struct save_area_ext *dump_save_area_create(int cpu) 51 { 52 struct save_area_ext **save_areas, *save_area; 53 54 save_area = kmalloc(sizeof(*save_area), GFP_KERNEL); 55 if (!save_area) 56 return NULL; 57 if (cpu + 1 > dump_save_areas.count) { 58 dump_save_areas.count = cpu + 1; 59 save_areas = krealloc(dump_save_areas.areas, 60 dump_save_areas.count * sizeof(void *), 61 GFP_KERNEL | __GFP_ZERO); 62 if (!save_areas) { 63 kfree(save_area); 64 return NULL; 65 } 66 dump_save_areas.areas = save_areas; 67 } 68 dump_save_areas.areas[cpu] = save_area; 69 return save_area; 70 } 71 72 /* 73 * Return physical address for virtual address 74 */ 75 static inline void *load_real_addr(void *addr) 76 { 77 unsigned long real_addr; 78 79 asm volatile( 80 " lra %0,0(%1)\n" 81 " jz 0f\n" 82 " la %0,0\n" 83 "0:" 84 : "=a" (real_addr) : "a" (addr) : "cc"); 85 return (void *)real_addr; 86 } 87 88 /* 89 * Copy real to virtual or real memory 90 */ 91 static int copy_from_realmem(void *dest, void *src, size_t count) 92 { 93 unsigned long size; 94 95 if (!count) 96 return 0; 97 if (!is_vmalloc_or_module_addr(dest)) 98 return memcpy_real(dest, src, count); 99 do { 100 size = min(count, PAGE_SIZE - (__pa(dest) & ~PAGE_MASK)); 101 if (memcpy_real(load_real_addr(dest), src, size)) 102 return -EFAULT; 103 count -= size; 104 dest += size; 105 src += size; 106 } while (count); 107 return 0; 108 } 109 110 /* 111 * Pointer to ELF header in new kernel 112 */ 113 static void *elfcorehdr_newmem; 114 115 /* 116 * Copy one page from zfcpdump "oldmem" 117 * 118 * For pages below HSA size memory from the HSA is copied. Otherwise 119 * real memory copy is used. 120 */ 121 static ssize_t copy_oldmem_page_zfcpdump(char *buf, size_t csize, 122 unsigned long src, int userbuf) 123 { 124 int rc; 125 126 if (src < sclp.hsa_size) { 127 rc = memcpy_hsa(buf, src, csize, userbuf); 128 } else { 129 if (userbuf) 130 rc = copy_to_user_real((void __force __user *) buf, 131 (void *) src, csize); 132 else 133 rc = memcpy_real(buf, (void *) src, csize); 134 } 135 return rc ? rc : csize; 136 } 137 138 /* 139 * Copy one page from kdump "oldmem" 140 * 141 * For the kdump reserved memory this functions performs a swap operation: 142 * - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE]. 143 * - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] 144 */ 145 static ssize_t copy_oldmem_page_kdump(char *buf, size_t csize, 146 unsigned long src, int userbuf) 147 148 { 149 int rc; 150 151 if (src < OLDMEM_SIZE) 152 src += OLDMEM_BASE; 153 else if (src > OLDMEM_BASE && 154 src < OLDMEM_BASE + OLDMEM_SIZE) 155 src -= OLDMEM_BASE; 156 if (userbuf) 157 rc = copy_to_user_real((void __force __user *) buf, 158 (void *) src, csize); 159 else 160 rc = copy_from_realmem(buf, (void *) src, csize); 161 return (rc == 0) ? rc : csize; 162 } 163 164 /* 165 * Copy one page from "oldmem" 166 */ 167 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, 168 unsigned long offset, int userbuf) 169 { 170 unsigned long src; 171 172 if (!csize) 173 return 0; 174 src = (pfn << PAGE_SHIFT) + offset; 175 if (OLDMEM_BASE) 176 return copy_oldmem_page_kdump(buf, csize, src, userbuf); 177 else 178 return copy_oldmem_page_zfcpdump(buf, csize, src, userbuf); 179 } 180 181 /* 182 * Remap "oldmem" for kdump 183 * 184 * For the kdump reserved memory this functions performs a swap operation: 185 * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] 186 */ 187 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma, 188 unsigned long from, unsigned long pfn, 189 unsigned long size, pgprot_t prot) 190 { 191 unsigned long size_old; 192 int rc; 193 194 if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) { 195 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT)); 196 rc = remap_pfn_range(vma, from, 197 pfn + (OLDMEM_BASE >> PAGE_SHIFT), 198 size_old, prot); 199 if (rc || size == size_old) 200 return rc; 201 size -= size_old; 202 from += size_old; 203 pfn += size_old >> PAGE_SHIFT; 204 } 205 return remap_pfn_range(vma, from, pfn, size, prot); 206 } 207 208 /* 209 * Remap "oldmem" for zfcpdump 210 * 211 * We only map available memory above HSA size. Memory below HSA size 212 * is read on demand using the copy_oldmem_page() function. 213 */ 214 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma, 215 unsigned long from, 216 unsigned long pfn, 217 unsigned long size, pgprot_t prot) 218 { 219 unsigned long hsa_end = sclp.hsa_size; 220 unsigned long size_hsa; 221 222 if (pfn < hsa_end >> PAGE_SHIFT) { 223 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT)); 224 if (size == size_hsa) 225 return 0; 226 size -= size_hsa; 227 from += size_hsa; 228 pfn += size_hsa >> PAGE_SHIFT; 229 } 230 return remap_pfn_range(vma, from, pfn, size, prot); 231 } 232 233 /* 234 * Remap "oldmem" for kdump or zfcpdump 235 */ 236 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from, 237 unsigned long pfn, unsigned long size, pgprot_t prot) 238 { 239 if (OLDMEM_BASE) 240 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot); 241 else 242 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size, 243 prot); 244 } 245 246 /* 247 * Copy memory from old kernel 248 */ 249 int copy_from_oldmem(void *dest, void *src, size_t count) 250 { 251 unsigned long copied = 0; 252 int rc; 253 254 if (OLDMEM_BASE) { 255 if ((unsigned long) src < OLDMEM_SIZE) { 256 copied = min(count, OLDMEM_SIZE - (unsigned long) src); 257 rc = copy_from_realmem(dest, src + OLDMEM_BASE, copied); 258 if (rc) 259 return rc; 260 } 261 } else { 262 unsigned long hsa_end = sclp.hsa_size; 263 if ((unsigned long) src < hsa_end) { 264 copied = min(count, hsa_end - (unsigned long) src); 265 rc = memcpy_hsa(dest, (unsigned long) src, copied, 0); 266 if (rc) 267 return rc; 268 } 269 } 270 return copy_from_realmem(dest + copied, src + copied, count - copied); 271 } 272 273 /* 274 * Alloc memory and panic in case of ENOMEM 275 */ 276 static void *kzalloc_panic(int len) 277 { 278 void *rc; 279 280 rc = kzalloc(len, GFP_KERNEL); 281 if (!rc) 282 panic("s390 kdump kzalloc (%d) failed", len); 283 return rc; 284 } 285 286 /* 287 * Initialize ELF note 288 */ 289 static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len, 290 const char *name) 291 { 292 Elf64_Nhdr *note; 293 u64 len; 294 295 note = (Elf64_Nhdr *)buf; 296 note->n_namesz = strlen(name) + 1; 297 note->n_descsz = d_len; 298 note->n_type = type; 299 len = sizeof(Elf64_Nhdr); 300 301 memcpy(buf + len, name, note->n_namesz); 302 len = roundup(len + note->n_namesz, 4); 303 304 memcpy(buf + len, desc, note->n_descsz); 305 len = roundup(len + note->n_descsz, 4); 306 307 return PTR_ADD(buf, len); 308 } 309 310 /* 311 * Initialize prstatus note 312 */ 313 static void *nt_prstatus(void *ptr, struct save_area *sa) 314 { 315 struct elf_prstatus nt_prstatus; 316 static int cpu_nr = 1; 317 318 memset(&nt_prstatus, 0, sizeof(nt_prstatus)); 319 memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs)); 320 memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw)); 321 memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs)); 322 nt_prstatus.pr_pid = cpu_nr; 323 cpu_nr++; 324 325 return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus), 326 "CORE"); 327 } 328 329 /* 330 * Initialize fpregset (floating point) note 331 */ 332 static void *nt_fpregset(void *ptr, struct save_area *sa) 333 { 334 elf_fpregset_t nt_fpregset; 335 336 memset(&nt_fpregset, 0, sizeof(nt_fpregset)); 337 memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg)); 338 memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs)); 339 340 return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset), 341 "CORE"); 342 } 343 344 /* 345 * Initialize timer note 346 */ 347 static void *nt_s390_timer(void *ptr, struct save_area *sa) 348 { 349 return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer), 350 KEXEC_CORE_NOTE_NAME); 351 } 352 353 /* 354 * Initialize TOD clock comparator note 355 */ 356 static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa) 357 { 358 return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp, 359 sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME); 360 } 361 362 /* 363 * Initialize TOD programmable register note 364 */ 365 static void *nt_s390_tod_preg(void *ptr, struct save_area *sa) 366 { 367 return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg, 368 sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME); 369 } 370 371 /* 372 * Initialize control register note 373 */ 374 static void *nt_s390_ctrs(void *ptr, struct save_area *sa) 375 { 376 return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs, 377 sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME); 378 } 379 380 /* 381 * Initialize prefix register note 382 */ 383 static void *nt_s390_prefix(void *ptr, struct save_area *sa) 384 { 385 return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg, 386 sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME); 387 } 388 389 /* 390 * Initialize vxrs high note (full 128 bit VX registers 16-31) 391 */ 392 static void *nt_s390_vx_high(void *ptr, __vector128 *vx_regs) 393 { 394 return nt_init(ptr, NT_S390_VXRS_HIGH, &vx_regs[16], 395 16 * sizeof(__vector128), KEXEC_CORE_NOTE_NAME); 396 } 397 398 /* 399 * Initialize vxrs low note (lower halves of VX registers 0-15) 400 */ 401 static void *nt_s390_vx_low(void *ptr, __vector128 *vx_regs) 402 { 403 Elf64_Nhdr *note; 404 u64 len; 405 int i; 406 407 note = (Elf64_Nhdr *)ptr; 408 note->n_namesz = strlen(KEXEC_CORE_NOTE_NAME) + 1; 409 note->n_descsz = 16 * 8; 410 note->n_type = NT_S390_VXRS_LOW; 411 len = sizeof(Elf64_Nhdr); 412 413 memcpy(ptr + len, KEXEC_CORE_NOTE_NAME, note->n_namesz); 414 len = roundup(len + note->n_namesz, 4); 415 416 ptr += len; 417 /* Copy lower halves of SIMD registers 0-15 */ 418 for (i = 0; i < 16; i++) { 419 memcpy(ptr, &vx_regs[i], 8); 420 ptr += 8; 421 } 422 return ptr; 423 } 424 425 /* 426 * Fill ELF notes for one CPU with save area registers 427 */ 428 void *fill_cpu_elf_notes(void *ptr, struct save_area *sa, __vector128 *vx_regs) 429 { 430 ptr = nt_prstatus(ptr, sa); 431 ptr = nt_fpregset(ptr, sa); 432 ptr = nt_s390_timer(ptr, sa); 433 ptr = nt_s390_tod_cmp(ptr, sa); 434 ptr = nt_s390_tod_preg(ptr, sa); 435 ptr = nt_s390_ctrs(ptr, sa); 436 ptr = nt_s390_prefix(ptr, sa); 437 if (MACHINE_HAS_VX && vx_regs) { 438 ptr = nt_s390_vx_low(ptr, vx_regs); 439 ptr = nt_s390_vx_high(ptr, vx_regs); 440 } 441 return ptr; 442 } 443 444 /* 445 * Initialize prpsinfo note (new kernel) 446 */ 447 static void *nt_prpsinfo(void *ptr) 448 { 449 struct elf_prpsinfo prpsinfo; 450 451 memset(&prpsinfo, 0, sizeof(prpsinfo)); 452 prpsinfo.pr_sname = 'R'; 453 strcpy(prpsinfo.pr_fname, "vmlinux"); 454 return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo), 455 KEXEC_CORE_NOTE_NAME); 456 } 457 458 /* 459 * Get vmcoreinfo using lowcore->vmcore_info (new kernel) 460 */ 461 static void *get_vmcoreinfo_old(unsigned long *size) 462 { 463 char nt_name[11], *vmcoreinfo; 464 Elf64_Nhdr note; 465 void *addr; 466 467 if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr))) 468 return NULL; 469 memset(nt_name, 0, sizeof(nt_name)); 470 if (copy_from_oldmem(¬e, addr, sizeof(note))) 471 return NULL; 472 if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1)) 473 return NULL; 474 if (strcmp(nt_name, "VMCOREINFO") != 0) 475 return NULL; 476 vmcoreinfo = kzalloc_panic(note.n_descsz); 477 if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz)) 478 return NULL; 479 *size = note.n_descsz; 480 return vmcoreinfo; 481 } 482 483 /* 484 * Initialize vmcoreinfo note (new kernel) 485 */ 486 static void *nt_vmcoreinfo(void *ptr) 487 { 488 unsigned long size; 489 void *vmcoreinfo; 490 491 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size); 492 if (!vmcoreinfo) 493 vmcoreinfo = get_vmcoreinfo_old(&size); 494 if (!vmcoreinfo) 495 return ptr; 496 return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO"); 497 } 498 499 /* 500 * Initialize ELF header (new kernel) 501 */ 502 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt) 503 { 504 memset(ehdr, 0, sizeof(*ehdr)); 505 memcpy(ehdr->e_ident, ELFMAG, SELFMAG); 506 ehdr->e_ident[EI_CLASS] = ELFCLASS64; 507 ehdr->e_ident[EI_DATA] = ELFDATA2MSB; 508 ehdr->e_ident[EI_VERSION] = EV_CURRENT; 509 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); 510 ehdr->e_type = ET_CORE; 511 ehdr->e_machine = EM_S390; 512 ehdr->e_version = EV_CURRENT; 513 ehdr->e_phoff = sizeof(Elf64_Ehdr); 514 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 515 ehdr->e_phentsize = sizeof(Elf64_Phdr); 516 ehdr->e_phnum = mem_chunk_cnt + 1; 517 return ehdr + 1; 518 } 519 520 /* 521 * Return CPU count for ELF header (new kernel) 522 */ 523 static int get_cpu_cnt(void) 524 { 525 int i, cpus = 0; 526 527 for (i = 0; i < dump_save_areas.count; i++) { 528 if (dump_save_areas.areas[i]->sa.pref_reg == 0) 529 continue; 530 cpus++; 531 } 532 return cpus; 533 } 534 535 /* 536 * Return memory chunk count for ELF header (new kernel) 537 */ 538 static int get_mem_chunk_cnt(void) 539 { 540 int cnt = 0; 541 u64 idx; 542 543 for_each_dump_mem_range(idx, NUMA_NO_NODE, NULL, NULL, NULL) 544 cnt++; 545 return cnt; 546 } 547 548 /* 549 * Initialize ELF loads (new kernel) 550 */ 551 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset) 552 { 553 phys_addr_t start, end; 554 u64 idx; 555 556 for_each_dump_mem_range(idx, NUMA_NO_NODE, &start, &end, NULL) { 557 phdr->p_filesz = end - start; 558 phdr->p_type = PT_LOAD; 559 phdr->p_offset = start; 560 phdr->p_vaddr = start; 561 phdr->p_paddr = start; 562 phdr->p_memsz = end - start; 563 phdr->p_flags = PF_R | PF_W | PF_X; 564 phdr->p_align = PAGE_SIZE; 565 phdr++; 566 } 567 } 568 569 /* 570 * Initialize notes (new kernel) 571 */ 572 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset) 573 { 574 struct save_area_ext *sa_ext; 575 void *ptr_start = ptr; 576 int i; 577 578 ptr = nt_prpsinfo(ptr); 579 580 for (i = 0; i < dump_save_areas.count; i++) { 581 sa_ext = dump_save_areas.areas[i]; 582 if (sa_ext->sa.pref_reg == 0) 583 continue; 584 ptr = fill_cpu_elf_notes(ptr, &sa_ext->sa, sa_ext->vx_regs); 585 } 586 ptr = nt_vmcoreinfo(ptr); 587 memset(phdr, 0, sizeof(*phdr)); 588 phdr->p_type = PT_NOTE; 589 phdr->p_offset = notes_offset; 590 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start); 591 phdr->p_memsz = phdr->p_filesz; 592 return ptr; 593 } 594 595 /* 596 * Create ELF core header (new kernel) 597 */ 598 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size) 599 { 600 Elf64_Phdr *phdr_notes, *phdr_loads; 601 int mem_chunk_cnt; 602 void *ptr, *hdr; 603 u32 alloc_size; 604 u64 hdr_off; 605 606 /* If we are not in kdump or zfcpdump mode return */ 607 if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP) 608 return 0; 609 /* If elfcorehdr= has been passed via cmdline, we use that one */ 610 if (elfcorehdr_addr != ELFCORE_ADDR_MAX) 611 return 0; 612 /* If we cannot get HSA size for zfcpdump return error */ 613 if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size) 614 return -ENODEV; 615 616 /* For kdump, exclude previous crashkernel memory */ 617 if (OLDMEM_BASE) { 618 oldmem_region.base = OLDMEM_BASE; 619 oldmem_region.size = OLDMEM_SIZE; 620 oldmem_type.total_size = OLDMEM_SIZE; 621 } 622 623 mem_chunk_cnt = get_mem_chunk_cnt(); 624 625 alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 + 626 mem_chunk_cnt * sizeof(Elf64_Phdr); 627 hdr = kzalloc_panic(alloc_size); 628 /* Init elf header */ 629 ptr = ehdr_init(hdr, mem_chunk_cnt); 630 /* Init program headers */ 631 phdr_notes = ptr; 632 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr)); 633 phdr_loads = ptr; 634 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt); 635 /* Init notes */ 636 hdr_off = PTR_DIFF(ptr, hdr); 637 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off); 638 /* Init loads */ 639 hdr_off = PTR_DIFF(ptr, hdr); 640 loads_init(phdr_loads, hdr_off); 641 *addr = (unsigned long long) hdr; 642 elfcorehdr_newmem = hdr; 643 *size = (unsigned long long) hdr_off; 644 BUG_ON(elfcorehdr_size > alloc_size); 645 return 0; 646 } 647 648 /* 649 * Free ELF core header (new kernel) 650 */ 651 void elfcorehdr_free(unsigned long long addr) 652 { 653 if (!elfcorehdr_newmem) 654 return; 655 kfree((void *)(unsigned long)addr); 656 } 657 658 /* 659 * Read from ELF header 660 */ 661 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) 662 { 663 void *src = (void *)(unsigned long)*ppos; 664 665 src = elfcorehdr_newmem ? src : src - OLDMEM_BASE; 666 memcpy(buf, src, count); 667 *ppos += count; 668 return count; 669 } 670 671 /* 672 * Read from ELF notes data 673 */ 674 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos) 675 { 676 void *src = (void *)(unsigned long)*ppos; 677 int rc; 678 679 if (elfcorehdr_newmem) { 680 memcpy(buf, src, count); 681 } else { 682 rc = copy_from_oldmem(buf, src, count); 683 if (rc) 684 return rc; 685 } 686 *ppos += count; 687 return count; 688 } 689