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TOMOYO Linux Cross Reference
Linux/fs/proc/vmcore.c

Version: ~ [ linux-5.6 ] ~ [ linux-5.5.13 ] ~ [ linux-5.4.28 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.113 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.174 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.217 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.217 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *      fs/proc/vmcore.c Interface for accessing the crash
  3  *                               dump from the system's previous life.
  4  *      Heavily borrowed from fs/proc/kcore.c
  5  *      Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
  6  *      Copyright (C) IBM Corporation, 2004. All rights reserved
  7  *
  8  */
  9 
 10 #include <linux/mm.h>
 11 #include <linux/kcore.h>
 12 #include <linux/user.h>
 13 #include <linux/elf.h>
 14 #include <linux/elfcore.h>
 15 #include <linux/export.h>
 16 #include <linux/slab.h>
 17 #include <linux/highmem.h>
 18 #include <linux/printk.h>
 19 #include <linux/bootmem.h>
 20 #include <linux/init.h>
 21 #include <linux/crash_dump.h>
 22 #include <linux/list.h>
 23 #include <asm/uaccess.h>
 24 #include <asm/io.h>
 25 #include "internal.h"
 26 
 27 /* List representing chunks of contiguous memory areas and their offsets in
 28  * vmcore file.
 29  */
 30 static LIST_HEAD(vmcore_list);
 31 
 32 /* Stores the pointer to the buffer containing kernel elf core headers. */
 33 static char *elfcorebuf;
 34 static size_t elfcorebuf_sz;
 35 
 36 /* Total size of vmcore file. */
 37 static u64 vmcore_size;
 38 
 39 static struct proc_dir_entry *proc_vmcore = NULL;
 40 
 41 /*
 42  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
 43  * The called function has to take care of module refcounting.
 44  */
 45 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
 46 
 47 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
 48 {
 49         if (oldmem_pfn_is_ram)
 50                 return -EBUSY;
 51         oldmem_pfn_is_ram = fn;
 52         return 0;
 53 }
 54 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
 55 
 56 void unregister_oldmem_pfn_is_ram(void)
 57 {
 58         oldmem_pfn_is_ram = NULL;
 59         wmb();
 60 }
 61 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
 62 
 63 static int pfn_is_ram(unsigned long pfn)
 64 {
 65         int (*fn)(unsigned long pfn);
 66         /* pfn is ram unless fn() checks pagetype */
 67         int ret = 1;
 68 
 69         /*
 70          * Ask hypervisor if the pfn is really ram.
 71          * A ballooned page contains no data and reading from such a page
 72          * will cause high load in the hypervisor.
 73          */
 74         fn = oldmem_pfn_is_ram;
 75         if (fn)
 76                 ret = fn(pfn);
 77 
 78         return ret;
 79 }
 80 
 81 /* Reads a page from the oldmem device from given offset. */
 82 static ssize_t read_from_oldmem(char *buf, size_t count,
 83                                 u64 *ppos, int userbuf)
 84 {
 85         unsigned long pfn, offset;
 86         size_t nr_bytes;
 87         ssize_t read = 0, tmp;
 88 
 89         if (!count)
 90                 return 0;
 91 
 92         offset = (unsigned long)(*ppos % PAGE_SIZE);
 93         pfn = (unsigned long)(*ppos / PAGE_SIZE);
 94 
 95         do {
 96                 if (count > (PAGE_SIZE - offset))
 97                         nr_bytes = PAGE_SIZE - offset;
 98                 else
 99                         nr_bytes = count;
100 
101                 /* If pfn is not ram, return zeros for sparse dump files */
102                 if (pfn_is_ram(pfn) == 0)
103                         memset(buf, 0, nr_bytes);
104                 else {
105                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
106                                                 offset, userbuf);
107                         if (tmp < 0)
108                                 return tmp;
109                 }
110                 *ppos += nr_bytes;
111                 count -= nr_bytes;
112                 buf += nr_bytes;
113                 read += nr_bytes;
114                 ++pfn;
115                 offset = 0;
116         } while (count);
117 
118         return read;
119 }
120 
121 /* Maps vmcore file offset to respective physical address in memroy. */
122 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
123                                         struct vmcore **m_ptr)
124 {
125         struct vmcore *m;
126         u64 paddr;
127 
128         list_for_each_entry(m, vc_list, list) {
129                 u64 start, end;
130                 start = m->offset;
131                 end = m->offset + m->size - 1;
132                 if (offset >= start && offset <= end) {
133                         paddr = m->paddr + offset - start;
134                         *m_ptr = m;
135                         return paddr;
136                 }
137         }
138         *m_ptr = NULL;
139         return 0;
140 }
141 
142 /* Read from the ELF header and then the crash dump. On error, negative value is
143  * returned otherwise number of bytes read are returned.
144  */
145 static ssize_t read_vmcore(struct file *file, char __user *buffer,
146                                 size_t buflen, loff_t *fpos)
147 {
148         ssize_t acc = 0, tmp;
149         size_t tsz;
150         u64 start, nr_bytes;
151         struct vmcore *curr_m = NULL;
152 
153         if (buflen == 0 || *fpos >= vmcore_size)
154                 return 0;
155 
156         /* trim buflen to not go beyond EOF */
157         if (buflen > vmcore_size - *fpos)
158                 buflen = vmcore_size - *fpos;
159 
160         /* Read ELF core header */
161         if (*fpos < elfcorebuf_sz) {
162                 tsz = elfcorebuf_sz - *fpos;
163                 if (buflen < tsz)
164                         tsz = buflen;
165                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
166                         return -EFAULT;
167                 buflen -= tsz;
168                 *fpos += tsz;
169                 buffer += tsz;
170                 acc += tsz;
171 
172                 /* leave now if filled buffer already */
173                 if (buflen == 0)
174                         return acc;
175         }
176 
177         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
178         if (!curr_m)
179                 return -EINVAL;
180 
181         while (buflen) {
182                 tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK));
183 
184                 /* Calculate left bytes in current memory segment. */
185                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
186                 if (tsz > nr_bytes)
187                         tsz = nr_bytes;
188 
189                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
190                 if (tmp < 0)
191                         return tmp;
192                 buflen -= tsz;
193                 *fpos += tsz;
194                 buffer += tsz;
195                 acc += tsz;
196                 if (start >= (curr_m->paddr + curr_m->size)) {
197                         if (curr_m->list.next == &vmcore_list)
198                                 return acc;     /*EOF*/
199                         curr_m = list_entry(curr_m->list.next,
200                                                 struct vmcore, list);
201                         start = curr_m->paddr;
202                 }
203         }
204         return acc;
205 }
206 
207 static const struct file_operations proc_vmcore_operations = {
208         .read           = read_vmcore,
209         .llseek         = default_llseek,
210 };
211 
212 static struct vmcore* __init get_new_element(void)
213 {
214         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
215 }
216 
217 static u64 __init get_vmcore_size_elf64(char *elfptr)
218 {
219         int i;
220         u64 size;
221         Elf64_Ehdr *ehdr_ptr;
222         Elf64_Phdr *phdr_ptr;
223 
224         ehdr_ptr = (Elf64_Ehdr *)elfptr;
225         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
226         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
227         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
228                 size += phdr_ptr->p_memsz;
229                 phdr_ptr++;
230         }
231         return size;
232 }
233 
234 static u64 __init get_vmcore_size_elf32(char *elfptr)
235 {
236         int i;
237         u64 size;
238         Elf32_Ehdr *ehdr_ptr;
239         Elf32_Phdr *phdr_ptr;
240 
241         ehdr_ptr = (Elf32_Ehdr *)elfptr;
242         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
243         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
244         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
245                 size += phdr_ptr->p_memsz;
246                 phdr_ptr++;
247         }
248         return size;
249 }
250 
251 /* Merges all the PT_NOTE headers into one. */
252 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
253                                                 struct list_head *vc_list)
254 {
255         int i, nr_ptnote=0, rc=0;
256         char *tmp;
257         Elf64_Ehdr *ehdr_ptr;
258         Elf64_Phdr phdr, *phdr_ptr;
259         Elf64_Nhdr *nhdr_ptr;
260         u64 phdr_sz = 0, note_off;
261 
262         ehdr_ptr = (Elf64_Ehdr *)elfptr;
263         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
264         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
265                 int j;
266                 void *notes_section;
267                 struct vmcore *new;
268                 u64 offset, max_sz, sz, real_sz = 0;
269                 if (phdr_ptr->p_type != PT_NOTE)
270                         continue;
271                 nr_ptnote++;
272                 max_sz = phdr_ptr->p_memsz;
273                 offset = phdr_ptr->p_offset;
274                 notes_section = kmalloc(max_sz, GFP_KERNEL);
275                 if (!notes_section)
276                         return -ENOMEM;
277                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
278                 if (rc < 0) {
279                         kfree(notes_section);
280                         return rc;
281                 }
282                 nhdr_ptr = notes_section;
283                 for (j = 0; j < max_sz; j += sz) {
284                         if (nhdr_ptr->n_namesz == 0)
285                                 break;
286                         sz = sizeof(Elf64_Nhdr) +
287                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
288                                 ((nhdr_ptr->n_descsz + 3) & ~3);
289                         real_sz += sz;
290                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
291                 }
292 
293                 /* Add this contiguous chunk of notes section to vmcore list.*/
294                 new = get_new_element();
295                 if (!new) {
296                         kfree(notes_section);
297                         return -ENOMEM;
298                 }
299                 new->paddr = phdr_ptr->p_offset;
300                 new->size = real_sz;
301                 list_add_tail(&new->list, vc_list);
302                 phdr_sz += real_sz;
303                 kfree(notes_section);
304         }
305 
306         /* Prepare merged PT_NOTE program header. */
307         phdr.p_type    = PT_NOTE;
308         phdr.p_flags   = 0;
309         note_off = sizeof(Elf64_Ehdr) +
310                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
311         phdr.p_offset  = note_off;
312         phdr.p_vaddr   = phdr.p_paddr = 0;
313         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
314         phdr.p_align   = 0;
315 
316         /* Add merged PT_NOTE program header*/
317         tmp = elfptr + sizeof(Elf64_Ehdr);
318         memcpy(tmp, &phdr, sizeof(phdr));
319         tmp += sizeof(phdr);
320 
321         /* Remove unwanted PT_NOTE program headers. */
322         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
323         *elfsz = *elfsz - i;
324         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
325 
326         /* Modify e_phnum to reflect merged headers. */
327         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
328 
329         return 0;
330 }
331 
332 /* Merges all the PT_NOTE headers into one. */
333 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
334                                                 struct list_head *vc_list)
335 {
336         int i, nr_ptnote=0, rc=0;
337         char *tmp;
338         Elf32_Ehdr *ehdr_ptr;
339         Elf32_Phdr phdr, *phdr_ptr;
340         Elf32_Nhdr *nhdr_ptr;
341         u64 phdr_sz = 0, note_off;
342 
343         ehdr_ptr = (Elf32_Ehdr *)elfptr;
344         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
345         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
346                 int j;
347                 void *notes_section;
348                 struct vmcore *new;
349                 u64 offset, max_sz, sz, real_sz = 0;
350                 if (phdr_ptr->p_type != PT_NOTE)
351                         continue;
352                 nr_ptnote++;
353                 max_sz = phdr_ptr->p_memsz;
354                 offset = phdr_ptr->p_offset;
355                 notes_section = kmalloc(max_sz, GFP_KERNEL);
356                 if (!notes_section)
357                         return -ENOMEM;
358                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
359                 if (rc < 0) {
360                         kfree(notes_section);
361                         return rc;
362                 }
363                 nhdr_ptr = notes_section;
364                 for (j = 0; j < max_sz; j += sz) {
365                         if (nhdr_ptr->n_namesz == 0)
366                                 break;
367                         sz = sizeof(Elf32_Nhdr) +
368                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
369                                 ((nhdr_ptr->n_descsz + 3) & ~3);
370                         real_sz += sz;
371                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
372                 }
373 
374                 /* Add this contiguous chunk of notes section to vmcore list.*/
375                 new = get_new_element();
376                 if (!new) {
377                         kfree(notes_section);
378                         return -ENOMEM;
379                 }
380                 new->paddr = phdr_ptr->p_offset;
381                 new->size = real_sz;
382                 list_add_tail(&new->list, vc_list);
383                 phdr_sz += real_sz;
384                 kfree(notes_section);
385         }
386 
387         /* Prepare merged PT_NOTE program header. */
388         phdr.p_type    = PT_NOTE;
389         phdr.p_flags   = 0;
390         note_off = sizeof(Elf32_Ehdr) +
391                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
392         phdr.p_offset  = note_off;
393         phdr.p_vaddr   = phdr.p_paddr = 0;
394         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
395         phdr.p_align   = 0;
396 
397         /* Add merged PT_NOTE program header*/
398         tmp = elfptr + sizeof(Elf32_Ehdr);
399         memcpy(tmp, &phdr, sizeof(phdr));
400         tmp += sizeof(phdr);
401 
402         /* Remove unwanted PT_NOTE program headers. */
403         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
404         *elfsz = *elfsz - i;
405         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
406 
407         /* Modify e_phnum to reflect merged headers. */
408         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
409 
410         return 0;
411 }
412 
413 /* Add memory chunks represented by program headers to vmcore list. Also update
414  * the new offset fields of exported program headers. */
415 static int __init process_ptload_program_headers_elf64(char *elfptr,
416                                                 size_t elfsz,
417                                                 struct list_head *vc_list)
418 {
419         int i;
420         Elf64_Ehdr *ehdr_ptr;
421         Elf64_Phdr *phdr_ptr;
422         loff_t vmcore_off;
423         struct vmcore *new;
424 
425         ehdr_ptr = (Elf64_Ehdr *)elfptr;
426         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
427 
428         /* First program header is PT_NOTE header. */
429         vmcore_off = sizeof(Elf64_Ehdr) +
430                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
431                         phdr_ptr->p_memsz; /* Note sections */
432 
433         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
434                 if (phdr_ptr->p_type != PT_LOAD)
435                         continue;
436 
437                 /* Add this contiguous chunk of memory to vmcore list.*/
438                 new = get_new_element();
439                 if (!new)
440                         return -ENOMEM;
441                 new->paddr = phdr_ptr->p_offset;
442                 new->size = phdr_ptr->p_memsz;
443                 list_add_tail(&new->list, vc_list);
444 
445                 /* Update the program header offset. */
446                 phdr_ptr->p_offset = vmcore_off;
447                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
448         }
449         return 0;
450 }
451 
452 static int __init process_ptload_program_headers_elf32(char *elfptr,
453                                                 size_t elfsz,
454                                                 struct list_head *vc_list)
455 {
456         int i;
457         Elf32_Ehdr *ehdr_ptr;
458         Elf32_Phdr *phdr_ptr;
459         loff_t vmcore_off;
460         struct vmcore *new;
461 
462         ehdr_ptr = (Elf32_Ehdr *)elfptr;
463         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
464 
465         /* First program header is PT_NOTE header. */
466         vmcore_off = sizeof(Elf32_Ehdr) +
467                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
468                         phdr_ptr->p_memsz; /* Note sections */
469 
470         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
471                 if (phdr_ptr->p_type != PT_LOAD)
472                         continue;
473 
474                 /* Add this contiguous chunk of memory to vmcore list.*/
475                 new = get_new_element();
476                 if (!new)
477                         return -ENOMEM;
478                 new->paddr = phdr_ptr->p_offset;
479                 new->size = phdr_ptr->p_memsz;
480                 list_add_tail(&new->list, vc_list);
481 
482                 /* Update the program header offset */
483                 phdr_ptr->p_offset = vmcore_off;
484                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
485         }
486         return 0;
487 }
488 
489 /* Sets offset fields of vmcore elements. */
490 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
491                                                 struct list_head *vc_list)
492 {
493         loff_t vmcore_off;
494         Elf64_Ehdr *ehdr_ptr;
495         struct vmcore *m;
496 
497         ehdr_ptr = (Elf64_Ehdr *)elfptr;
498 
499         /* Skip Elf header and program headers. */
500         vmcore_off = sizeof(Elf64_Ehdr) +
501                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
502 
503         list_for_each_entry(m, vc_list, list) {
504                 m->offset = vmcore_off;
505                 vmcore_off += m->size;
506         }
507 }
508 
509 /* Sets offset fields of vmcore elements. */
510 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
511                                                 struct list_head *vc_list)
512 {
513         loff_t vmcore_off;
514         Elf32_Ehdr *ehdr_ptr;
515         struct vmcore *m;
516 
517         ehdr_ptr = (Elf32_Ehdr *)elfptr;
518 
519         /* Skip Elf header and program headers. */
520         vmcore_off = sizeof(Elf32_Ehdr) +
521                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
522 
523         list_for_each_entry(m, vc_list, list) {
524                 m->offset = vmcore_off;
525                 vmcore_off += m->size;
526         }
527 }
528 
529 static int __init parse_crash_elf64_headers(void)
530 {
531         int rc=0;
532         Elf64_Ehdr ehdr;
533         u64 addr;
534 
535         addr = elfcorehdr_addr;
536 
537         /* Read Elf header */
538         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
539         if (rc < 0)
540                 return rc;
541 
542         /* Do some basic Verification. */
543         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
544                 (ehdr.e_type != ET_CORE) ||
545                 !vmcore_elf64_check_arch(&ehdr) ||
546                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
547                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
548                 ehdr.e_version != EV_CURRENT ||
549                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
550                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
551                 ehdr.e_phnum == 0) {
552                 pr_warn("Warning: Core image elf header is not sane\n");
553                 return -EINVAL;
554         }
555 
556         /* Read in all elf headers. */
557         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
558         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
559         if (!elfcorebuf)
560                 return -ENOMEM;
561         addr = elfcorehdr_addr;
562         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
563         if (rc < 0) {
564                 kfree(elfcorebuf);
565                 return rc;
566         }
567 
568         /* Merge all PT_NOTE headers into one. */
569         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
570         if (rc) {
571                 kfree(elfcorebuf);
572                 return rc;
573         }
574         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
575                                                         &vmcore_list);
576         if (rc) {
577                 kfree(elfcorebuf);
578                 return rc;
579         }
580         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
581         return 0;
582 }
583 
584 static int __init parse_crash_elf32_headers(void)
585 {
586         int rc=0;
587         Elf32_Ehdr ehdr;
588         u64 addr;
589 
590         addr = elfcorehdr_addr;
591 
592         /* Read Elf header */
593         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
594         if (rc < 0)
595                 return rc;
596 
597         /* Do some basic Verification. */
598         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
599                 (ehdr.e_type != ET_CORE) ||
600                 !elf_check_arch(&ehdr) ||
601                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
602                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
603                 ehdr.e_version != EV_CURRENT ||
604                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
605                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
606                 ehdr.e_phnum == 0) {
607                 pr_warn("Warning: Core image elf header is not sane\n");
608                 return -EINVAL;
609         }
610 
611         /* Read in all elf headers. */
612         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
613         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
614         if (!elfcorebuf)
615                 return -ENOMEM;
616         addr = elfcorehdr_addr;
617         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
618         if (rc < 0) {
619                 kfree(elfcorebuf);
620                 return rc;
621         }
622 
623         /* Merge all PT_NOTE headers into one. */
624         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
625         if (rc) {
626                 kfree(elfcorebuf);
627                 return rc;
628         }
629         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
630                                                                 &vmcore_list);
631         if (rc) {
632                 kfree(elfcorebuf);
633                 return rc;
634         }
635         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
636         return 0;
637 }
638 
639 static int __init parse_crash_elf_headers(void)
640 {
641         unsigned char e_ident[EI_NIDENT];
642         u64 addr;
643         int rc=0;
644 
645         addr = elfcorehdr_addr;
646         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
647         if (rc < 0)
648                 return rc;
649         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
650                 pr_warn("Warning: Core image elf header not found\n");
651                 return -EINVAL;
652         }
653 
654         if (e_ident[EI_CLASS] == ELFCLASS64) {
655                 rc = parse_crash_elf64_headers();
656                 if (rc)
657                         return rc;
658 
659                 /* Determine vmcore size. */
660                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
661         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
662                 rc = parse_crash_elf32_headers();
663                 if (rc)
664                         return rc;
665 
666                 /* Determine vmcore size. */
667                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
668         } else {
669                 pr_warn("Warning: Core image elf header is not sane\n");
670                 return -EINVAL;
671         }
672         return 0;
673 }
674 
675 /* Init function for vmcore module. */
676 static int __init vmcore_init(void)
677 {
678         int rc = 0;
679 
680         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
681         if (!(is_vmcore_usable()))
682                 return rc;
683         rc = parse_crash_elf_headers();
684         if (rc) {
685                 pr_warn("Kdump: vmcore not initialized\n");
686                 return rc;
687         }
688 
689         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
690         if (proc_vmcore)
691                 proc_vmcore->size = vmcore_size;
692         return 0;
693 }
694 module_init(vmcore_init)
695 
696 /* Cleanup function for vmcore module. */
697 void vmcore_cleanup(void)
698 {
699         struct list_head *pos, *next;
700 
701         if (proc_vmcore) {
702                 proc_remove(proc_vmcore);
703                 proc_vmcore = NULL;
704         }
705 
706         /* clear the vmcore list. */
707         list_for_each_safe(pos, next, &vmcore_list) {
708                 struct vmcore *m;
709 
710                 m = list_entry(pos, struct vmcore, list);
711                 list_del(&m->list);
712                 kfree(m);
713         }
714         kfree(elfcorebuf);
715         elfcorebuf = NULL;
716 }
717 EXPORT_SYMBOL_GPL(vmcore_cleanup);
718 

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