1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * S390 kdump implementation
4 *
5 * Copyright IBM Corp. 2011
6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
7 */
8
9 #include <linux/crash_dump.h>
10 #include <asm/lowcore.h>
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/mm.h>
14 #include <linux/gfp.h>
15 #include <linux/slab.h>
16 #include <linux/bootmem.h>
17 #include <linux/elf.h>
18 #include <asm/asm-offsets.h>
19 #include <linux/memblock.h>
20 #include <asm/os_info.h>
21 #include <asm/elf.h>
22 #include <asm/ipl.h>
23 #include <asm/sclp.h>
24
25 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
26 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
27 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
28
29 static struct memblock_region oldmem_region;
30
31 static struct memblock_type oldmem_type = {
32 .cnt = 1,
33 .max = 1,
34 .total_size = 0,
35 .regions = &oldmem_region,
36 .name = "oldmem",
37 };
38
39 struct save_area {
40 struct list_head list;
41 u64 psw[2];
42 u64 ctrs[16];
43 u64 gprs[16];
44 u32 acrs[16];
45 u64 fprs[16];
46 u32 fpc;
47 u32 prefix;
48 u64 todpreg;
49 u64 timer;
50 u64 todcmp;
51 u64 vxrs_low[16];
52 __vector128 vxrs_high[16];
53 };
54
55 static LIST_HEAD(dump_save_areas);
56
57 /*
58 * Allocate a save area
59 */
save_area_alloc(bool is_boot_cpu)60 struct save_area * __init save_area_alloc(bool is_boot_cpu)
61 {
62 struct save_area *sa;
63
64 sa = (void *) memblock_alloc(sizeof(*sa), 8);
65 if (is_boot_cpu)
66 list_add(&sa->list, &dump_save_areas);
67 else
68 list_add_tail(&sa->list, &dump_save_areas);
69 return sa;
70 }
71
72 /*
73 * Return the address of the save area for the boot CPU
74 */
save_area_boot_cpu(void)75 struct save_area * __init save_area_boot_cpu(void)
76 {
77 return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
78 }
79
80 /*
81 * Copy CPU registers into the save area
82 */
save_area_add_regs(struct save_area * sa,void * regs)83 void __init save_area_add_regs(struct save_area *sa, void *regs)
84 {
85 struct lowcore *lc;
86
87 lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
88 memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
89 memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
90 memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
91 memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
92 memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
93 memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
94 memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
95 memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
96 memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
97 memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
98 }
99
100 /*
101 * Copy vector registers into the save area
102 */
save_area_add_vxrs(struct save_area * sa,__vector128 * vxrs)103 void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
104 {
105 int i;
106
107 /* Copy lower halves of vector registers 0-15 */
108 for (i = 0; i < 16; i++)
109 memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
110 /* Copy vector registers 16-31 */
111 memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
112 }
113
114 /*
115 * Return physical address for virtual address
116 */
load_real_addr(void * addr)117 static inline void *load_real_addr(void *addr)
118 {
119 unsigned long real_addr;
120
121 asm volatile(
122 " lra %0,0(%1)\n"
123 " jz 0f\n"
124 " la %0,0\n"
125 "0:"
126 : "=a" (real_addr) : "a" (addr) : "cc");
127 return (void *)real_addr;
128 }
129
130 /*
131 * Copy memory of the old, dumped system to a kernel space virtual address
132 */
copy_oldmem_kernel(void * dst,void * src,size_t count)133 int copy_oldmem_kernel(void *dst, void *src, size_t count)
134 {
135 unsigned long from, len;
136 void *ra;
137 int rc;
138
139 while (count) {
140 from = __pa(src);
141 if (!OLDMEM_BASE && from < sclp.hsa_size) {
142 /* Copy from zfcpdump HSA area */
143 len = min(count, sclp.hsa_size - from);
144 rc = memcpy_hsa_kernel(dst, from, len);
145 if (rc)
146 return rc;
147 } else {
148 /* Check for swapped kdump oldmem areas */
149 if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
150 from -= OLDMEM_BASE;
151 len = min(count, OLDMEM_SIZE - from);
152 } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
153 len = min(count, OLDMEM_SIZE - from);
154 from += OLDMEM_BASE;
155 } else {
156 len = count;
157 }
158 if (is_vmalloc_or_module_addr(dst)) {
159 ra = load_real_addr(dst);
160 len = min(PAGE_SIZE - offset_in_page(ra), len);
161 } else {
162 ra = dst;
163 }
164 if (memcpy_real(ra, (void *) from, len))
165 return -EFAULT;
166 }
167 dst += len;
168 src += len;
169 count -= len;
170 }
171 return 0;
172 }
173
174 /*
175 * Copy memory of the old, dumped system to a user space virtual address
176 */
copy_oldmem_user(void __user * dst,void * src,size_t count)177 static int copy_oldmem_user(void __user *dst, void *src, size_t count)
178 {
179 unsigned long from, len;
180 int rc;
181
182 while (count) {
183 from = __pa(src);
184 if (!OLDMEM_BASE && from < sclp.hsa_size) {
185 /* Copy from zfcpdump HSA area */
186 len = min(count, sclp.hsa_size - from);
187 rc = memcpy_hsa_user(dst, from, len);
188 if (rc)
189 return rc;
190 } else {
191 /* Check for swapped kdump oldmem areas */
192 if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
193 from -= OLDMEM_BASE;
194 len = min(count, OLDMEM_SIZE - from);
195 } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
196 len = min(count, OLDMEM_SIZE - from);
197 from += OLDMEM_BASE;
198 } else {
199 len = count;
200 }
201 rc = copy_to_user_real(dst, (void *) from, count);
202 if (rc)
203 return rc;
204 }
205 dst += len;
206 src += len;
207 count -= len;
208 }
209 return 0;
210 }
211
212 /*
213 * Copy one page from "oldmem"
214 */
copy_oldmem_page(unsigned long pfn,char * buf,size_t csize,unsigned long offset,int userbuf)215 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
216 unsigned long offset, int userbuf)
217 {
218 void *src;
219 int rc;
220
221 if (!csize)
222 return 0;
223 src = (void *) (pfn << PAGE_SHIFT) + offset;
224 if (userbuf)
225 rc = copy_oldmem_user((void __force __user *) buf, src, csize);
226 else
227 rc = copy_oldmem_kernel((void *) buf, src, csize);
228 return rc;
229 }
230
231 /*
232 * Remap "oldmem" for kdump
233 *
234 * For the kdump reserved memory this functions performs a swap operation:
235 * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
236 */
remap_oldmem_pfn_range_kdump(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)237 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
238 unsigned long from, unsigned long pfn,
239 unsigned long size, pgprot_t prot)
240 {
241 unsigned long size_old;
242 int rc;
243
244 if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
245 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
246 rc = remap_pfn_range(vma, from,
247 pfn + (OLDMEM_BASE >> PAGE_SHIFT),
248 size_old, prot);
249 if (rc || size == size_old)
250 return rc;
251 size -= size_old;
252 from += size_old;
253 pfn += size_old >> PAGE_SHIFT;
254 }
255 return remap_pfn_range(vma, from, pfn, size, prot);
256 }
257
258 /*
259 * Remap "oldmem" for zfcpdump
260 *
261 * We only map available memory above HSA size. Memory below HSA size
262 * is read on demand using the copy_oldmem_page() function.
263 */
remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)264 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
265 unsigned long from,
266 unsigned long pfn,
267 unsigned long size, pgprot_t prot)
268 {
269 unsigned long hsa_end = sclp.hsa_size;
270 unsigned long size_hsa;
271
272 if (pfn < hsa_end >> PAGE_SHIFT) {
273 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
274 if (size == size_hsa)
275 return 0;
276 size -= size_hsa;
277 from += size_hsa;
278 pfn += size_hsa >> PAGE_SHIFT;
279 }
280 return remap_pfn_range(vma, from, pfn, size, prot);
281 }
282
283 /*
284 * Remap "oldmem" for kdump or zfcpdump
285 */
remap_oldmem_pfn_range(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)286 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
287 unsigned long pfn, unsigned long size, pgprot_t prot)
288 {
289 if (OLDMEM_BASE)
290 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
291 else
292 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
293 prot);
294 }
295
296 /*
297 * Alloc memory and panic in case of ENOMEM
298 */
kzalloc_panic(int len)299 static void *kzalloc_panic(int len)
300 {
301 void *rc;
302
303 rc = kzalloc(len, GFP_KERNEL);
304 if (!rc)
305 panic("s390 kdump kzalloc (%d) failed", len);
306 return rc;
307 }
308
309 /*
310 * Initialize ELF note
311 */
nt_init_name(void * buf,Elf64_Word type,void * desc,int d_len,const char * name)312 static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
313 const char *name)
314 {
315 Elf64_Nhdr *note;
316 u64 len;
317
318 note = (Elf64_Nhdr *)buf;
319 note->n_namesz = strlen(name) + 1;
320 note->n_descsz = d_len;
321 note->n_type = type;
322 len = sizeof(Elf64_Nhdr);
323
324 memcpy(buf + len, name, note->n_namesz);
325 len = roundup(len + note->n_namesz, 4);
326
327 memcpy(buf + len, desc, note->n_descsz);
328 len = roundup(len + note->n_descsz, 4);
329
330 return PTR_ADD(buf, len);
331 }
332
nt_init(void * buf,Elf64_Word type,void * desc,int d_len)333 static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
334 {
335 const char *note_name = "LINUX";
336
337 if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
338 note_name = KEXEC_CORE_NOTE_NAME;
339 return nt_init_name(buf, type, desc, d_len, note_name);
340 }
341
342 /*
343 * Fill ELF notes for one CPU with save area registers
344 */
fill_cpu_elf_notes(void * ptr,int cpu,struct save_area * sa)345 static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
346 {
347 struct elf_prstatus nt_prstatus;
348 elf_fpregset_t nt_fpregset;
349
350 /* Prepare prstatus note */
351 memset(&nt_prstatus, 0, sizeof(nt_prstatus));
352 memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
353 memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
354 memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
355 nt_prstatus.pr_pid = cpu;
356 /* Prepare fpregset (floating point) note */
357 memset(&nt_fpregset, 0, sizeof(nt_fpregset));
358 memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
359 memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
360 /* Create ELF notes for the CPU */
361 ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
362 ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
363 ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
364 ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
365 ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
366 ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
367 ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
368 if (MACHINE_HAS_VX) {
369 ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
370 &sa->vxrs_high, sizeof(sa->vxrs_high));
371 ptr = nt_init(ptr, NT_S390_VXRS_LOW,
372 &sa->vxrs_low, sizeof(sa->vxrs_low));
373 }
374 return ptr;
375 }
376
377 /*
378 * Initialize prpsinfo note (new kernel)
379 */
nt_prpsinfo(void * ptr)380 static void *nt_prpsinfo(void *ptr)
381 {
382 struct elf_prpsinfo prpsinfo;
383
384 memset(&prpsinfo, 0, sizeof(prpsinfo));
385 prpsinfo.pr_sname = 'R';
386 strcpy(prpsinfo.pr_fname, "vmlinux");
387 return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
388 }
389
390 /*
391 * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
392 */
get_vmcoreinfo_old(unsigned long * size)393 static void *get_vmcoreinfo_old(unsigned long *size)
394 {
395 char nt_name[11], *vmcoreinfo;
396 Elf64_Nhdr note;
397 void *addr;
398
399 if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
400 return NULL;
401 memset(nt_name, 0, sizeof(nt_name));
402 if (copy_oldmem_kernel(¬e, addr, sizeof(note)))
403 return NULL;
404 if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
405 sizeof(nt_name) - 1))
406 return NULL;
407 if (strcmp(nt_name, VMCOREINFO_NOTE_NAME) != 0)
408 return NULL;
409 vmcoreinfo = kzalloc_panic(note.n_descsz);
410 if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz)) {
411 kfree(vmcoreinfo);
412 return NULL;
413 }
414 *size = note.n_descsz;
415 return vmcoreinfo;
416 }
417
418 /*
419 * Initialize vmcoreinfo note (new kernel)
420 */
nt_vmcoreinfo(void * ptr)421 static void *nt_vmcoreinfo(void *ptr)
422 {
423 const char *name = VMCOREINFO_NOTE_NAME;
424 unsigned long size;
425 void *vmcoreinfo;
426
427 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
428 if (vmcoreinfo)
429 return nt_init_name(ptr, 0, vmcoreinfo, size, name);
430
431 vmcoreinfo = get_vmcoreinfo_old(&size);
432 if (!vmcoreinfo)
433 return ptr;
434 ptr = nt_init_name(ptr, 0, vmcoreinfo, size, name);
435 kfree(vmcoreinfo);
436 return ptr;
437 }
438
439 /*
440 * Initialize final note (needed for /proc/vmcore code)
441 */
nt_final(void * ptr)442 static void *nt_final(void *ptr)
443 {
444 Elf64_Nhdr *note;
445
446 note = (Elf64_Nhdr *) ptr;
447 note->n_namesz = 0;
448 note->n_descsz = 0;
449 note->n_type = 0;
450 return PTR_ADD(ptr, sizeof(Elf64_Nhdr));
451 }
452
453 /*
454 * Initialize ELF header (new kernel)
455 */
ehdr_init(Elf64_Ehdr * ehdr,int mem_chunk_cnt)456 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
457 {
458 memset(ehdr, 0, sizeof(*ehdr));
459 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
460 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
461 ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
462 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
463 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
464 ehdr->e_type = ET_CORE;
465 ehdr->e_machine = EM_S390;
466 ehdr->e_version = EV_CURRENT;
467 ehdr->e_phoff = sizeof(Elf64_Ehdr);
468 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
469 ehdr->e_phentsize = sizeof(Elf64_Phdr);
470 ehdr->e_phnum = mem_chunk_cnt + 1;
471 return ehdr + 1;
472 }
473
474 /*
475 * Return CPU count for ELF header (new kernel)
476 */
get_cpu_cnt(void)477 static int get_cpu_cnt(void)
478 {
479 struct save_area *sa;
480 int cpus = 0;
481
482 list_for_each_entry(sa, &dump_save_areas, list)
483 if (sa->prefix != 0)
484 cpus++;
485 return cpus;
486 }
487
488 /*
489 * Return memory chunk count for ELF header (new kernel)
490 */
get_mem_chunk_cnt(void)491 static int get_mem_chunk_cnt(void)
492 {
493 int cnt = 0;
494 u64 idx;
495
496 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
497 MEMBLOCK_NONE, NULL, NULL, NULL)
498 cnt++;
499 return cnt;
500 }
501
502 /*
503 * Initialize ELF loads (new kernel)
504 */
loads_init(Elf64_Phdr * phdr,u64 loads_offset)505 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
506 {
507 phys_addr_t start, end;
508 u64 idx;
509
510 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
511 MEMBLOCK_NONE, &start, &end, NULL) {
512 phdr->p_filesz = end - start;
513 phdr->p_type = PT_LOAD;
514 phdr->p_offset = start;
515 phdr->p_vaddr = start;
516 phdr->p_paddr = start;
517 phdr->p_memsz = end - start;
518 phdr->p_flags = PF_R | PF_W | PF_X;
519 phdr->p_align = PAGE_SIZE;
520 phdr++;
521 }
522 }
523
524 /*
525 * Initialize notes (new kernel)
526 */
notes_init(Elf64_Phdr * phdr,void * ptr,u64 notes_offset)527 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
528 {
529 struct save_area *sa;
530 void *ptr_start = ptr;
531 int cpu;
532
533 ptr = nt_prpsinfo(ptr);
534
535 cpu = 1;
536 list_for_each_entry(sa, &dump_save_areas, list)
537 if (sa->prefix != 0)
538 ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
539 ptr = nt_vmcoreinfo(ptr);
540 ptr = nt_final(ptr);
541 memset(phdr, 0, sizeof(*phdr));
542 phdr->p_type = PT_NOTE;
543 phdr->p_offset = notes_offset;
544 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
545 phdr->p_memsz = phdr->p_filesz;
546 return ptr;
547 }
548
549 /*
550 * Create ELF core header (new kernel)
551 */
elfcorehdr_alloc(unsigned long long * addr,unsigned long long * size)552 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
553 {
554 Elf64_Phdr *phdr_notes, *phdr_loads;
555 int mem_chunk_cnt;
556 void *ptr, *hdr;
557 u32 alloc_size;
558 u64 hdr_off;
559
560 /* If we are not in kdump or zfcpdump mode return */
561 if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
562 return 0;
563 /* If we cannot get HSA size for zfcpdump return error */
564 if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
565 return -ENODEV;
566
567 /* For kdump, exclude previous crashkernel memory */
568 if (OLDMEM_BASE) {
569 oldmem_region.base = OLDMEM_BASE;
570 oldmem_region.size = OLDMEM_SIZE;
571 oldmem_type.total_size = OLDMEM_SIZE;
572 }
573
574 mem_chunk_cnt = get_mem_chunk_cnt();
575
576 alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
577 mem_chunk_cnt * sizeof(Elf64_Phdr);
578 hdr = kzalloc_panic(alloc_size);
579 /* Init elf header */
580 ptr = ehdr_init(hdr, mem_chunk_cnt);
581 /* Init program headers */
582 phdr_notes = ptr;
583 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
584 phdr_loads = ptr;
585 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
586 /* Init notes */
587 hdr_off = PTR_DIFF(ptr, hdr);
588 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
589 /* Init loads */
590 hdr_off = PTR_DIFF(ptr, hdr);
591 loads_init(phdr_loads, hdr_off);
592 *addr = (unsigned long long) hdr;
593 *size = (unsigned long long) hdr_off;
594 BUG_ON(elfcorehdr_size > alloc_size);
595 return 0;
596 }
597
598 /*
599 * Free ELF core header (new kernel)
600 */
elfcorehdr_free(unsigned long long addr)601 void elfcorehdr_free(unsigned long long addr)
602 {
603 kfree((void *)(unsigned long)addr);
604 }
605
606 /*
607 * Read from ELF header
608 */
elfcorehdr_read(char * buf,size_t count,u64 * ppos)609 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
610 {
611 void *src = (void *)(unsigned long)*ppos;
612
613 memcpy(buf, src, count);
614 *ppos += count;
615 return count;
616 }
617
618 /*
619 * Read from ELF notes data
620 */
elfcorehdr_read_notes(char * buf,size_t count,u64 * ppos)621 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
622 {
623 void *src = (void *)(unsigned long)*ppos;
624
625 memcpy(buf, src, count);
626 *ppos += count;
627 return count;
628 }
629