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

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ 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-3.16.75 ] ~ [ 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 ] ~
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  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 <linux/vmalloc.h>
 24 #include <asm/uaccess.h>
 25 #include <asm/io.h>
 26 #include "internal.h"
 27 
 28 /* List representing chunks of contiguous memory areas and their offsets in
 29  * vmcore file.
 30  */
 31 static LIST_HEAD(vmcore_list);
 32 
 33 /* Stores the pointer to the buffer containing kernel elf core headers. */
 34 static char *elfcorebuf;
 35 static size_t elfcorebuf_sz;
 36 static size_t elfcorebuf_sz_orig;
 37 
 38 static char *elfnotes_buf;
 39 static size_t elfnotes_sz;
 40 
 41 /* Total size of vmcore file. */
 42 static u64 vmcore_size;
 43 
 44 static struct proc_dir_entry *proc_vmcore = NULL;
 45 
 46 /*
 47  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
 48  * The called function has to take care of module refcounting.
 49  */
 50 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
 51 
 52 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
 53 {
 54         if (oldmem_pfn_is_ram)
 55                 return -EBUSY;
 56         oldmem_pfn_is_ram = fn;
 57         return 0;
 58 }
 59 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
 60 
 61 void unregister_oldmem_pfn_is_ram(void)
 62 {
 63         oldmem_pfn_is_ram = NULL;
 64         wmb();
 65 }
 66 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
 67 
 68 static int pfn_is_ram(unsigned long pfn)
 69 {
 70         int (*fn)(unsigned long pfn);
 71         /* pfn is ram unless fn() checks pagetype */
 72         int ret = 1;
 73 
 74         /*
 75          * Ask hypervisor if the pfn is really ram.
 76          * A ballooned page contains no data and reading from such a page
 77          * will cause high load in the hypervisor.
 78          */
 79         fn = oldmem_pfn_is_ram;
 80         if (fn)
 81                 ret = fn(pfn);
 82 
 83         return ret;
 84 }
 85 
 86 /* Reads a page from the oldmem device from given offset. */
 87 static ssize_t read_from_oldmem(char *buf, size_t count,
 88                                 u64 *ppos, int userbuf)
 89 {
 90         unsigned long pfn, offset;
 91         size_t nr_bytes;
 92         ssize_t read = 0, tmp;
 93 
 94         if (!count)
 95                 return 0;
 96 
 97         offset = (unsigned long)(*ppos % PAGE_SIZE);
 98         pfn = (unsigned long)(*ppos / PAGE_SIZE);
 99 
100         do {
101                 if (count > (PAGE_SIZE - offset))
102                         nr_bytes = PAGE_SIZE - offset;
103                 else
104                         nr_bytes = count;
105 
106                 /* If pfn is not ram, return zeros for sparse dump files */
107                 if (pfn_is_ram(pfn) == 0)
108                         memset(buf, 0, nr_bytes);
109                 else {
110                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
111                                                 offset, userbuf);
112                         if (tmp < 0)
113                                 return tmp;
114                 }
115                 *ppos += nr_bytes;
116                 count -= nr_bytes;
117                 buf += nr_bytes;
118                 read += nr_bytes;
119                 ++pfn;
120                 offset = 0;
121         } while (count);
122 
123         return read;
124 }
125 
126 /* Read from the ELF header and then the crash dump. On error, negative value is
127  * returned otherwise number of bytes read are returned.
128  */
129 static ssize_t read_vmcore(struct file *file, char __user *buffer,
130                                 size_t buflen, loff_t *fpos)
131 {
132         ssize_t acc = 0, tmp;
133         size_t tsz;
134         u64 start;
135         struct vmcore *m = NULL;
136 
137         if (buflen == 0 || *fpos >= vmcore_size)
138                 return 0;
139 
140         /* trim buflen to not go beyond EOF */
141         if (buflen > vmcore_size - *fpos)
142                 buflen = vmcore_size - *fpos;
143 
144         /* Read ELF core header */
145         if (*fpos < elfcorebuf_sz) {
146                 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
147                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
148                         return -EFAULT;
149                 buflen -= tsz;
150                 *fpos += tsz;
151                 buffer += tsz;
152                 acc += tsz;
153 
154                 /* leave now if filled buffer already */
155                 if (buflen == 0)
156                         return acc;
157         }
158 
159         /* Read Elf note segment */
160         if (*fpos < elfcorebuf_sz + elfnotes_sz) {
161                 void *kaddr;
162 
163                 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
164                 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
165                 if (copy_to_user(buffer, kaddr, 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         list_for_each_entry(m, &vmcore_list, list) {
178                 if (*fpos < m->offset + m->size) {
179                         tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
180                         start = m->paddr + *fpos - m->offset;
181                         tmp = read_from_oldmem(buffer, tsz, &start, 1);
182                         if (tmp < 0)
183                                 return tmp;
184                         buflen -= tsz;
185                         *fpos += tsz;
186                         buffer += tsz;
187                         acc += tsz;
188 
189                         /* leave now if filled buffer already */
190                         if (buflen == 0)
191                                 return acc;
192                 }
193         }
194 
195         return acc;
196 }
197 
198 /**
199  * alloc_elfnotes_buf - allocate buffer for ELF note segment in
200  *                      vmalloc memory
201  *
202  * @notes_sz: size of buffer
203  *
204  * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
205  * the buffer to user-space by means of remap_vmalloc_range().
206  *
207  * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
208  * disabled and there's no need to allow users to mmap the buffer.
209  */
210 static inline char *alloc_elfnotes_buf(size_t notes_sz)
211 {
212 #ifdef CONFIG_MMU
213         return vmalloc_user(notes_sz);
214 #else
215         return vzalloc(notes_sz);
216 #endif
217 }
218 
219 /*
220  * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
221  * essential for mmap_vmcore() in order to map physically
222  * non-contiguous objects (ELF header, ELF note segment and memory
223  * regions in the 1st kernel pointed to by PT_LOAD entries) into
224  * virtually contiguous user-space in ELF layout.
225  */
226 #if defined(CONFIG_MMU) && !defined(CONFIG_S390)
227 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
228 {
229         size_t size = vma->vm_end - vma->vm_start;
230         u64 start, end, len, tsz;
231         struct vmcore *m;
232 
233         start = (u64)vma->vm_pgoff << PAGE_SHIFT;
234         end = start + size;
235 
236         if (size > vmcore_size || end > vmcore_size)
237                 return -EINVAL;
238 
239         if (vma->vm_flags & (VM_WRITE | VM_EXEC))
240                 return -EPERM;
241 
242         vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
243         vma->vm_flags |= VM_MIXEDMAP;
244 
245         len = 0;
246 
247         if (start < elfcorebuf_sz) {
248                 u64 pfn;
249 
250                 tsz = min(elfcorebuf_sz - (size_t)start, size);
251                 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
252                 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
253                                     vma->vm_page_prot))
254                         return -EAGAIN;
255                 size -= tsz;
256                 start += tsz;
257                 len += tsz;
258 
259                 if (size == 0)
260                         return 0;
261         }
262 
263         if (start < elfcorebuf_sz + elfnotes_sz) {
264                 void *kaddr;
265 
266                 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
267                 kaddr = elfnotes_buf + start - elfcorebuf_sz;
268                 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
269                                                 kaddr, tsz))
270                         goto fail;
271                 size -= tsz;
272                 start += tsz;
273                 len += tsz;
274 
275                 if (size == 0)
276                         return 0;
277         }
278 
279         list_for_each_entry(m, &vmcore_list, list) {
280                 if (start < m->offset + m->size) {
281                         u64 paddr = 0;
282 
283                         tsz = min_t(size_t, m->offset + m->size - start, size);
284                         paddr = m->paddr + start - m->offset;
285                         if (remap_pfn_range(vma, vma->vm_start + len,
286                                             paddr >> PAGE_SHIFT, tsz,
287                                             vma->vm_page_prot))
288                                 goto fail;
289                         size -= tsz;
290                         start += tsz;
291                         len += tsz;
292 
293                         if (size == 0)
294                                 return 0;
295                 }
296         }
297 
298         return 0;
299 fail:
300         do_munmap(vma->vm_mm, vma->vm_start, len);
301         return -EAGAIN;
302 }
303 #else
304 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
305 {
306         return -ENOSYS;
307 }
308 #endif
309 
310 static const struct file_operations proc_vmcore_operations = {
311         .read           = read_vmcore,
312         .llseek         = default_llseek,
313         .mmap           = mmap_vmcore,
314 };
315 
316 static struct vmcore* __init get_new_element(void)
317 {
318         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
319 }
320 
321 static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
322                                   struct list_head *vc_list)
323 {
324         u64 size;
325         struct vmcore *m;
326 
327         size = elfsz + elfnotesegsz;
328         list_for_each_entry(m, vc_list, list) {
329                 size += m->size;
330         }
331         return size;
332 }
333 
334 /**
335  * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
336  *
337  * @ehdr_ptr: ELF header
338  *
339  * This function updates p_memsz member of each PT_NOTE entry in the
340  * program header table pointed to by @ehdr_ptr to real size of ELF
341  * note segment.
342  */
343 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
344 {
345         int i, rc=0;
346         Elf64_Phdr *phdr_ptr;
347         Elf64_Nhdr *nhdr_ptr;
348 
349         phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
350         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
351                 void *notes_section;
352                 u64 offset, max_sz, sz, real_sz = 0;
353                 if (phdr_ptr->p_type != PT_NOTE)
354                         continue;
355                 max_sz = phdr_ptr->p_memsz;
356                 offset = phdr_ptr->p_offset;
357                 notes_section = kmalloc(max_sz, GFP_KERNEL);
358                 if (!notes_section)
359                         return -ENOMEM;
360                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
361                 if (rc < 0) {
362                         kfree(notes_section);
363                         return rc;
364                 }
365                 nhdr_ptr = notes_section;
366                 while (real_sz < max_sz) {
367                         if (nhdr_ptr->n_namesz == 0)
368                                 break;
369                         sz = sizeof(Elf64_Nhdr) +
370                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
371                                 ((nhdr_ptr->n_descsz + 3) & ~3);
372                         real_sz += sz;
373                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
374                 }
375                 kfree(notes_section);
376                 phdr_ptr->p_memsz = real_sz;
377         }
378 
379         return 0;
380 }
381 
382 /**
383  * get_note_number_and_size_elf64 - get the number of PT_NOTE program
384  * headers and sum of real size of their ELF note segment headers and
385  * data.
386  *
387  * @ehdr_ptr: ELF header
388  * @nr_ptnote: buffer for the number of PT_NOTE program headers
389  * @sz_ptnote: buffer for size of unique PT_NOTE program header
390  *
391  * This function is used to merge multiple PT_NOTE program headers
392  * into a unique single one. The resulting unique entry will have
393  * @sz_ptnote in its phdr->p_mem.
394  *
395  * It is assumed that program headers with PT_NOTE type pointed to by
396  * @ehdr_ptr has already been updated by update_note_header_size_elf64
397  * and each of PT_NOTE program headers has actual ELF note segment
398  * size in its p_memsz member.
399  */
400 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
401                                                  int *nr_ptnote, u64 *sz_ptnote)
402 {
403         int i;
404         Elf64_Phdr *phdr_ptr;
405 
406         *nr_ptnote = *sz_ptnote = 0;
407 
408         phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
409         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
410                 if (phdr_ptr->p_type != PT_NOTE)
411                         continue;
412                 *nr_ptnote += 1;
413                 *sz_ptnote += phdr_ptr->p_memsz;
414         }
415 
416         return 0;
417 }
418 
419 /**
420  * copy_notes_elf64 - copy ELF note segments in a given buffer
421  *
422  * @ehdr_ptr: ELF header
423  * @notes_buf: buffer into which ELF note segments are copied
424  *
425  * This function is used to copy ELF note segment in the 1st kernel
426  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
427  * size of the buffer @notes_buf is equal to or larger than sum of the
428  * real ELF note segment headers and data.
429  *
430  * It is assumed that program headers with PT_NOTE type pointed to by
431  * @ehdr_ptr has already been updated by update_note_header_size_elf64
432  * and each of PT_NOTE program headers has actual ELF note segment
433  * size in its p_memsz member.
434  */
435 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
436 {
437         int i, rc=0;
438         Elf64_Phdr *phdr_ptr;
439 
440         phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
441 
442         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
443                 u64 offset;
444                 if (phdr_ptr->p_type != PT_NOTE)
445                         continue;
446                 offset = phdr_ptr->p_offset;
447                 rc = read_from_oldmem(notes_buf, phdr_ptr->p_memsz, &offset, 0);
448                 if (rc < 0)
449                         return rc;
450                 notes_buf += phdr_ptr->p_memsz;
451         }
452 
453         return 0;
454 }
455 
456 /* Merges all the PT_NOTE headers into one. */
457 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
458                                            char **notes_buf, size_t *notes_sz)
459 {
460         int i, nr_ptnote=0, rc=0;
461         char *tmp;
462         Elf64_Ehdr *ehdr_ptr;
463         Elf64_Phdr phdr;
464         u64 phdr_sz = 0, note_off;
465 
466         ehdr_ptr = (Elf64_Ehdr *)elfptr;
467 
468         rc = update_note_header_size_elf64(ehdr_ptr);
469         if (rc < 0)
470                 return rc;
471 
472         rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
473         if (rc < 0)
474                 return rc;
475 
476         *notes_sz = roundup(phdr_sz, PAGE_SIZE);
477         *notes_buf = alloc_elfnotes_buf(*notes_sz);
478         if (!*notes_buf)
479                 return -ENOMEM;
480 
481         rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
482         if (rc < 0)
483                 return rc;
484 
485         /* Prepare merged PT_NOTE program header. */
486         phdr.p_type    = PT_NOTE;
487         phdr.p_flags   = 0;
488         note_off = sizeof(Elf64_Ehdr) +
489                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
490         phdr.p_offset  = roundup(note_off, PAGE_SIZE);
491         phdr.p_vaddr   = phdr.p_paddr = 0;
492         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
493         phdr.p_align   = 0;
494 
495         /* Add merged PT_NOTE program header*/
496         tmp = elfptr + sizeof(Elf64_Ehdr);
497         memcpy(tmp, &phdr, sizeof(phdr));
498         tmp += sizeof(phdr);
499 
500         /* Remove unwanted PT_NOTE program headers. */
501         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
502         *elfsz = *elfsz - i;
503         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
504         memset(elfptr + *elfsz, 0, i);
505         *elfsz = roundup(*elfsz, PAGE_SIZE);
506 
507         /* Modify e_phnum to reflect merged headers. */
508         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
509 
510         return 0;
511 }
512 
513 /**
514  * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
515  *
516  * @ehdr_ptr: ELF header
517  *
518  * This function updates p_memsz member of each PT_NOTE entry in the
519  * program header table pointed to by @ehdr_ptr to real size of ELF
520  * note segment.
521  */
522 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
523 {
524         int i, rc=0;
525         Elf32_Phdr *phdr_ptr;
526         Elf32_Nhdr *nhdr_ptr;
527 
528         phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
529         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
530                 void *notes_section;
531                 u64 offset, max_sz, sz, real_sz = 0;
532                 if (phdr_ptr->p_type != PT_NOTE)
533                         continue;
534                 max_sz = phdr_ptr->p_memsz;
535                 offset = phdr_ptr->p_offset;
536                 notes_section = kmalloc(max_sz, GFP_KERNEL);
537                 if (!notes_section)
538                         return -ENOMEM;
539                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
540                 if (rc < 0) {
541                         kfree(notes_section);
542                         return rc;
543                 }
544                 nhdr_ptr = notes_section;
545                 while (real_sz < max_sz) {
546                         if (nhdr_ptr->n_namesz == 0)
547                                 break;
548                         sz = sizeof(Elf32_Nhdr) +
549                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
550                                 ((nhdr_ptr->n_descsz + 3) & ~3);
551                         real_sz += sz;
552                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
553                 }
554                 kfree(notes_section);
555                 phdr_ptr->p_memsz = real_sz;
556         }
557 
558         return 0;
559 }
560 
561 /**
562  * get_note_number_and_size_elf32 - get the number of PT_NOTE program
563  * headers and sum of real size of their ELF note segment headers and
564  * data.
565  *
566  * @ehdr_ptr: ELF header
567  * @nr_ptnote: buffer for the number of PT_NOTE program headers
568  * @sz_ptnote: buffer for size of unique PT_NOTE program header
569  *
570  * This function is used to merge multiple PT_NOTE program headers
571  * into a unique single one. The resulting unique entry will have
572  * @sz_ptnote in its phdr->p_mem.
573  *
574  * It is assumed that program headers with PT_NOTE type pointed to by
575  * @ehdr_ptr has already been updated by update_note_header_size_elf32
576  * and each of PT_NOTE program headers has actual ELF note segment
577  * size in its p_memsz member.
578  */
579 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
580                                                  int *nr_ptnote, u64 *sz_ptnote)
581 {
582         int i;
583         Elf32_Phdr *phdr_ptr;
584 
585         *nr_ptnote = *sz_ptnote = 0;
586 
587         phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
588         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
589                 if (phdr_ptr->p_type != PT_NOTE)
590                         continue;
591                 *nr_ptnote += 1;
592                 *sz_ptnote += phdr_ptr->p_memsz;
593         }
594 
595         return 0;
596 }
597 
598 /**
599  * copy_notes_elf32 - copy ELF note segments in a given buffer
600  *
601  * @ehdr_ptr: ELF header
602  * @notes_buf: buffer into which ELF note segments are copied
603  *
604  * This function is used to copy ELF note segment in the 1st kernel
605  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
606  * size of the buffer @notes_buf is equal to or larger than sum of the
607  * real ELF note segment headers and data.
608  *
609  * It is assumed that program headers with PT_NOTE type pointed to by
610  * @ehdr_ptr has already been updated by update_note_header_size_elf32
611  * and each of PT_NOTE program headers has actual ELF note segment
612  * size in its p_memsz member.
613  */
614 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
615 {
616         int i, rc=0;
617         Elf32_Phdr *phdr_ptr;
618 
619         phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
620 
621         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
622                 u64 offset;
623                 if (phdr_ptr->p_type != PT_NOTE)
624                         continue;
625                 offset = phdr_ptr->p_offset;
626                 rc = read_from_oldmem(notes_buf, phdr_ptr->p_memsz, &offset, 0);
627                 if (rc < 0)
628                         return rc;
629                 notes_buf += phdr_ptr->p_memsz;
630         }
631 
632         return 0;
633 }
634 
635 /* Merges all the PT_NOTE headers into one. */
636 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
637                                            char **notes_buf, size_t *notes_sz)
638 {
639         int i, nr_ptnote=0, rc=0;
640         char *tmp;
641         Elf32_Ehdr *ehdr_ptr;
642         Elf32_Phdr phdr;
643         u64 phdr_sz = 0, note_off;
644 
645         ehdr_ptr = (Elf32_Ehdr *)elfptr;
646 
647         rc = update_note_header_size_elf32(ehdr_ptr);
648         if (rc < 0)
649                 return rc;
650 
651         rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
652         if (rc < 0)
653                 return rc;
654 
655         *notes_sz = roundup(phdr_sz, PAGE_SIZE);
656         *notes_buf = alloc_elfnotes_buf(*notes_sz);
657         if (!*notes_buf)
658                 return -ENOMEM;
659 
660         rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
661         if (rc < 0)
662                 return rc;
663 
664         /* Prepare merged PT_NOTE program header. */
665         phdr.p_type    = PT_NOTE;
666         phdr.p_flags   = 0;
667         note_off = sizeof(Elf32_Ehdr) +
668                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
669         phdr.p_offset  = roundup(note_off, PAGE_SIZE);
670         phdr.p_vaddr   = phdr.p_paddr = 0;
671         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
672         phdr.p_align   = 0;
673 
674         /* Add merged PT_NOTE program header*/
675         tmp = elfptr + sizeof(Elf32_Ehdr);
676         memcpy(tmp, &phdr, sizeof(phdr));
677         tmp += sizeof(phdr);
678 
679         /* Remove unwanted PT_NOTE program headers. */
680         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
681         *elfsz = *elfsz - i;
682         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
683         memset(elfptr + *elfsz, 0, i);
684         *elfsz = roundup(*elfsz, PAGE_SIZE);
685 
686         /* Modify e_phnum to reflect merged headers. */
687         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
688 
689         return 0;
690 }
691 
692 /* Add memory chunks represented by program headers to vmcore list. Also update
693  * the new offset fields of exported program headers. */
694 static int __init process_ptload_program_headers_elf64(char *elfptr,
695                                                 size_t elfsz,
696                                                 size_t elfnotes_sz,
697                                                 struct list_head *vc_list)
698 {
699         int i;
700         Elf64_Ehdr *ehdr_ptr;
701         Elf64_Phdr *phdr_ptr;
702         loff_t vmcore_off;
703         struct vmcore *new;
704 
705         ehdr_ptr = (Elf64_Ehdr *)elfptr;
706         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
707 
708         /* Skip Elf header, program headers and Elf note segment. */
709         vmcore_off = elfsz + elfnotes_sz;
710 
711         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
712                 u64 paddr, start, end, size;
713 
714                 if (phdr_ptr->p_type != PT_LOAD)
715                         continue;
716 
717                 paddr = phdr_ptr->p_offset;
718                 start = rounddown(paddr, PAGE_SIZE);
719                 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
720                 size = end - start;
721 
722                 /* Add this contiguous chunk of memory to vmcore list.*/
723                 new = get_new_element();
724                 if (!new)
725                         return -ENOMEM;
726                 new->paddr = start;
727                 new->size = size;
728                 list_add_tail(&new->list, vc_list);
729 
730                 /* Update the program header offset. */
731                 phdr_ptr->p_offset = vmcore_off + (paddr - start);
732                 vmcore_off = vmcore_off + size;
733         }
734         return 0;
735 }
736 
737 static int __init process_ptload_program_headers_elf32(char *elfptr,
738                                                 size_t elfsz,
739                                                 size_t elfnotes_sz,
740                                                 struct list_head *vc_list)
741 {
742         int i;
743         Elf32_Ehdr *ehdr_ptr;
744         Elf32_Phdr *phdr_ptr;
745         loff_t vmcore_off;
746         struct vmcore *new;
747 
748         ehdr_ptr = (Elf32_Ehdr *)elfptr;
749         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
750 
751         /* Skip Elf header, program headers and Elf note segment. */
752         vmcore_off = elfsz + elfnotes_sz;
753 
754         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
755                 u64 paddr, start, end, size;
756 
757                 if (phdr_ptr->p_type != PT_LOAD)
758                         continue;
759 
760                 paddr = phdr_ptr->p_offset;
761                 start = rounddown(paddr, PAGE_SIZE);
762                 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
763                 size = end - start;
764 
765                 /* Add this contiguous chunk of memory to vmcore list.*/
766                 new = get_new_element();
767                 if (!new)
768                         return -ENOMEM;
769                 new->paddr = start;
770                 new->size = size;
771                 list_add_tail(&new->list, vc_list);
772 
773                 /* Update the program header offset */
774                 phdr_ptr->p_offset = vmcore_off + (paddr - start);
775                 vmcore_off = vmcore_off + size;
776         }
777         return 0;
778 }
779 
780 /* Sets offset fields of vmcore elements. */
781 static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
782                                            struct list_head *vc_list)
783 {
784         loff_t vmcore_off;
785         struct vmcore *m;
786 
787         /* Skip Elf header, program headers and Elf note segment. */
788         vmcore_off = elfsz + elfnotes_sz;
789 
790         list_for_each_entry(m, vc_list, list) {
791                 m->offset = vmcore_off;
792                 vmcore_off += m->size;
793         }
794 }
795 
796 static void free_elfcorebuf(void)
797 {
798         free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
799         elfcorebuf = NULL;
800         vfree(elfnotes_buf);
801         elfnotes_buf = NULL;
802 }
803 
804 static int __init parse_crash_elf64_headers(void)
805 {
806         int rc=0;
807         Elf64_Ehdr ehdr;
808         u64 addr;
809 
810         addr = elfcorehdr_addr;
811 
812         /* Read Elf header */
813         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
814         if (rc < 0)
815                 return rc;
816 
817         /* Do some basic Verification. */
818         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
819                 (ehdr.e_type != ET_CORE) ||
820                 !vmcore_elf64_check_arch(&ehdr) ||
821                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
822                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
823                 ehdr.e_version != EV_CURRENT ||
824                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
825                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
826                 ehdr.e_phnum == 0) {
827                 pr_warn("Warning: Core image elf header is not sane\n");
828                 return -EINVAL;
829         }
830 
831         /* Read in all elf headers. */
832         elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
833                                 ehdr.e_phnum * sizeof(Elf64_Phdr);
834         elfcorebuf_sz = elfcorebuf_sz_orig;
835         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
836                                               get_order(elfcorebuf_sz_orig));
837         if (!elfcorebuf)
838                 return -ENOMEM;
839         addr = elfcorehdr_addr;
840         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
841         if (rc < 0)
842                 goto fail;
843 
844         /* Merge all PT_NOTE headers into one. */
845         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
846                                       &elfnotes_buf, &elfnotes_sz);
847         if (rc)
848                 goto fail;
849         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
850                                                   elfnotes_sz, &vmcore_list);
851         if (rc)
852                 goto fail;
853         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
854         return 0;
855 fail:
856         free_elfcorebuf();
857         return rc;
858 }
859 
860 static int __init parse_crash_elf32_headers(void)
861 {
862         int rc=0;
863         Elf32_Ehdr ehdr;
864         u64 addr;
865 
866         addr = elfcorehdr_addr;
867 
868         /* Read Elf header */
869         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
870         if (rc < 0)
871                 return rc;
872 
873         /* Do some basic Verification. */
874         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
875                 (ehdr.e_type != ET_CORE) ||
876                 !elf_check_arch(&ehdr) ||
877                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
878                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
879                 ehdr.e_version != EV_CURRENT ||
880                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
881                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
882                 ehdr.e_phnum == 0) {
883                 pr_warn("Warning: Core image elf header is not sane\n");
884                 return -EINVAL;
885         }
886 
887         /* Read in all elf headers. */
888         elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
889         elfcorebuf_sz = elfcorebuf_sz_orig;
890         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
891                                               get_order(elfcorebuf_sz_orig));
892         if (!elfcorebuf)
893                 return -ENOMEM;
894         addr = elfcorehdr_addr;
895         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
896         if (rc < 0)
897                 goto fail;
898 
899         /* Merge all PT_NOTE headers into one. */
900         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
901                                       &elfnotes_buf, &elfnotes_sz);
902         if (rc)
903                 goto fail;
904         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
905                                                   elfnotes_sz, &vmcore_list);
906         if (rc)
907                 goto fail;
908         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
909         return 0;
910 fail:
911         free_elfcorebuf();
912         return rc;
913 }
914 
915 static int __init parse_crash_elf_headers(void)
916 {
917         unsigned char e_ident[EI_NIDENT];
918         u64 addr;
919         int rc=0;
920 
921         addr = elfcorehdr_addr;
922         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
923         if (rc < 0)
924                 return rc;
925         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
926                 pr_warn("Warning: Core image elf header not found\n");
927                 return -EINVAL;
928         }
929 
930         if (e_ident[EI_CLASS] == ELFCLASS64) {
931                 rc = parse_crash_elf64_headers();
932                 if (rc)
933                         return rc;
934         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
935                 rc = parse_crash_elf32_headers();
936                 if (rc)
937                         return rc;
938         } else {
939                 pr_warn("Warning: Core image elf header is not sane\n");
940                 return -EINVAL;
941         }
942 
943         /* Determine vmcore size. */
944         vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
945                                       &vmcore_list);
946 
947         return 0;
948 }
949 
950 /* Init function for vmcore module. */
951 static int __init vmcore_init(void)
952 {
953         int rc = 0;
954 
955         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
956         if (!(is_vmcore_usable()))
957                 return rc;
958         rc = parse_crash_elf_headers();
959         if (rc) {
960                 pr_warn("Kdump: vmcore not initialized\n");
961                 return rc;
962         }
963 
964         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
965         if (proc_vmcore)
966                 proc_vmcore->size = vmcore_size;
967         return 0;
968 }
969 module_init(vmcore_init)
970 
971 /* Cleanup function for vmcore module. */
972 void vmcore_cleanup(void)
973 {
974         struct list_head *pos, *next;
975 
976         if (proc_vmcore) {
977                 proc_remove(proc_vmcore);
978                 proc_vmcore = NULL;
979         }
980 
981         /* clear the vmcore list. */
982         list_for_each_safe(pos, next, &vmcore_list) {
983                 struct vmcore *m;
984 
985                 m = list_entry(pos, struct vmcore, list);
986                 list_del(&m->list);
987                 kfree(m);
988         }
989         free_elfcorebuf();
990 }
991 EXPORT_SYMBOL_GPL(vmcore_cleanup);
992 

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