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Revert "ahci: added support for Freescale AHCI sata"
[linux-2.6/btrfs-unstable.git] / fs / proc / vmcore.c
blob4e61388ec03d2af3a426bb788f2382f4f27db1aa
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 <linux/pagemap.h>
25 #include <asm/uaccess.h>
26 #include <asm/io.h>
27 #include "internal.h"
28
29 /* List representing chunks of contiguous memory areas and their offsets in
30 * vmcore file.
31 */
32 static LIST_HEAD(vmcore_list);
33
34 /* Stores the pointer to the buffer containing kernel elf core headers. */
35 static char *elfcorebuf;
36 static size_t elfcorebuf_sz;
37 static size_t elfcorebuf_sz_orig;
38
39 static char *elfnotes_buf;
40 static size_t elfnotes_sz;
41
42 /* Total size of vmcore file. */
43 static u64 vmcore_size;
44
45 static struct proc_dir_entry *proc_vmcore;
46
47 /*
48 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
49 * The called function has to take care of module refcounting.
50 */
51 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
52
53 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
54 {
55 if (oldmem_pfn_is_ram)
56 return -EBUSY;
57 oldmem_pfn_is_ram = fn;
58 return 0;
59 }
60 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
61
62 void unregister_oldmem_pfn_is_ram(void)
63 {
64 oldmem_pfn_is_ram = NULL;
65 wmb();
66 }
67 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
68
69 static int pfn_is_ram(unsigned long pfn)
70 {
71 int (*fn)(unsigned long pfn);
72 /* pfn is ram unless fn() checks pagetype */
73 int ret = 1;
74
75 /*
76 * Ask hypervisor if the pfn is really ram.
77 * A ballooned page contains no data and reading from such a page
78 * will cause high load in the hypervisor.
79 */
80 fn = oldmem_pfn_is_ram;
81 if (fn)
82 ret = fn(pfn);
83
84 return ret;
85 }
86
87 /* Reads a page from the oldmem device from given offset. */
88 static ssize_t read_from_oldmem(char *buf, size_t count,
89 u64 *ppos, int userbuf)
90 {
91 unsigned long pfn, offset;
92 size_t nr_bytes;
93 ssize_t read = 0, tmp;
94
95 if (!count)
96 return 0;
97
98 offset = (unsigned long)(*ppos % PAGE_SIZE);
99 pfn = (unsigned long)(*ppos / PAGE_SIZE);
100
101 do {
102 if (count > (PAGE_SIZE - offset))
103 nr_bytes = PAGE_SIZE - offset;
104 else
105 nr_bytes = count;
106
107 /* If pfn is not ram, return zeros for sparse dump files */
108 if (pfn_is_ram(pfn) == 0)
109 memset(buf, 0, nr_bytes);
110 else {
111 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
112 offset, userbuf);
113 if (tmp < 0)
114 return tmp;
115 }
116 *ppos += nr_bytes;
117 count -= nr_bytes;
118 buf += nr_bytes;
119 read += nr_bytes;
120 ++pfn;
121 offset = 0;
122 } while (count);
123
124 return read;
125 }
126
127 /*
128 * Architectures may override this function to allocate ELF header in 2nd kernel
129 */
130 int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
131 {
132 return 0;
133 }
134
135 /*
136 * Architectures may override this function to free header
137 */
138 void __weak elfcorehdr_free(unsigned long long addr)
139 {}
140
141 /*
142 * Architectures may override this function to read from ELF header
143 */
144 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
145 {
146 return read_from_oldmem(buf, count, ppos, 0);
147 }
148
149 /*
150 * Architectures may override this function to read from notes sections
151 */
152 ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
153 {
154 return read_from_oldmem(buf, count, ppos, 0);
155 }
156
157 /*
158 * Architectures may override this function to map oldmem
159 */
160 int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
161 unsigned long from, unsigned long pfn,
162 unsigned long size, pgprot_t prot)
163 {
164 return remap_pfn_range(vma, from, pfn, size, prot);
165 }
166
167 /*
168 * Copy to either kernel or user space
169 */
170 static int copy_to(void *target, void *src, size_t size, int userbuf)
171 {
172 if (userbuf) {
173 if (copy_to_user((char __user *) target, src, size))
174 return -EFAULT;
175 } else {
176 memcpy(target, src, size);
177 }
178 return 0;
179 }
180
181 /* Read from the ELF header and then the crash dump. On error, negative value is
182 * returned otherwise number of bytes read are returned.
183 */
184 static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
185 int userbuf)
186 {
187 ssize_t acc = 0, tmp;
188 size_t tsz;
189 u64 start;
190 struct vmcore *m = NULL;
191
192 if (buflen == 0 || *fpos >= vmcore_size)
193 return 0;
194
195 /* trim buflen to not go beyond EOF */
196 if (buflen > vmcore_size - *fpos)
197 buflen = vmcore_size - *fpos;
198
199 /* Read ELF core header */
200 if (*fpos < elfcorebuf_sz) {
201 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
202 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
203 return -EFAULT;
204 buflen -= tsz;
205 *fpos += tsz;
206 buffer += tsz;
207 acc += tsz;
208
209 /* leave now if filled buffer already */
210 if (buflen == 0)
211 return acc;
212 }
213
214 /* Read Elf note segment */
215 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
216 void *kaddr;
217
218 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
219 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
220 if (copy_to(buffer, kaddr, tsz, userbuf))
221 return -EFAULT;
222 buflen -= tsz;
223 *fpos += tsz;
224 buffer += tsz;
225 acc += tsz;
226
227 /* leave now if filled buffer already */
228 if (buflen == 0)
229 return acc;
230 }
231
232 list_for_each_entry(m, &vmcore_list, list) {
233 if (*fpos < m->offset + m->size) {
234 tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
235 start = m->paddr + *fpos - m->offset;
236 tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
237 if (tmp < 0)
238 return tmp;
239 buflen -= tsz;
240 *fpos += tsz;
241 buffer += tsz;
242 acc += tsz;
243
244 /* leave now if filled buffer already */
245 if (buflen == 0)
246 return acc;
247 }
248 }
249
250 return acc;
251 }
252
253 static ssize_t read_vmcore(struct file *file, char __user *buffer,
254 size_t buflen, loff_t *fpos)
255 {
256 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
257 }
258
259 /*
260 * The vmcore fault handler uses the page cache and fills data using the
261 * standard __vmcore_read() function.
262 *
263 * On s390 the fault handler is used for memory regions that can't be mapped
264 * directly with remap_pfn_range().
265 */
266 static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
267 {
268 #ifdef CONFIG_S390
269 struct address_space *mapping = vma->vm_file->f_mapping;
270 pgoff_t index = vmf->pgoff;
271 struct page *page;
272 loff_t offset;
273 char *buf;
274 int rc;
275
276 page = find_or_create_page(mapping, index, GFP_KERNEL);
277 if (!page)
278 return VM_FAULT_OOM;
279 if (!PageUptodate(page)) {
280 offset = (loff_t) index << PAGE_CACHE_SHIFT;
281 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
282 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
283 if (rc < 0) {
284 unlock_page(page);
285 page_cache_release(page);
286 return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
287 }
288 SetPageUptodate(page);
289 }
290 unlock_page(page);
291 vmf->page = page;
292 return 0;
293 #else
294 return VM_FAULT_SIGBUS;
295 #endif
296 }
297
298 static const struct vm_operations_struct vmcore_mmap_ops = {
299 .fault = mmap_vmcore_fault,
300 };
301
302 /**
303 * alloc_elfnotes_buf - allocate buffer for ELF note segment in
304 * vmalloc memory
305 *
306 * @notes_sz: size of buffer
307 *
308 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
309 * the buffer to user-space by means of remap_vmalloc_range().
310 *
311 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
312 * disabled and there's no need to allow users to mmap the buffer.
313 */
314 static inline char *alloc_elfnotes_buf(size_t notes_sz)
315 {
316 #ifdef CONFIG_MMU
317 return vmalloc_user(notes_sz);
318 #else
319 return vzalloc(notes_sz);
320 #endif
321 }
322
323 /*
324 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
325 * essential for mmap_vmcore() in order to map physically
326 * non-contiguous objects (ELF header, ELF note segment and memory
327 * regions in the 1st kernel pointed to by PT_LOAD entries) into
328 * virtually contiguous user-space in ELF layout.
329 */
330 #ifdef CONFIG_MMU
331 /*
332 * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
333 * reported as not being ram with the zero page.
334 *
335 * @vma: vm_area_struct describing requested mapping
336 * @from: start remapping from
337 * @pfn: page frame number to start remapping to
338 * @size: remapping size
339 * @prot: protection bits
340 *
341 * Returns zero on success, -EAGAIN on failure.
342 */
343 static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
344 unsigned long from, unsigned long pfn,
345 unsigned long size, pgprot_t prot)
346 {
347 unsigned long map_size;
348 unsigned long pos_start, pos_end, pos;
349 unsigned long zeropage_pfn = my_zero_pfn(0);
350 size_t len = 0;
351
352 pos_start = pfn;
353 pos_end = pfn + (size >> PAGE_SHIFT);
354
355 for (pos = pos_start; pos < pos_end; ++pos) {
356 if (!pfn_is_ram(pos)) {
357 /*
358 * We hit a page which is not ram. Remap the continuous
359 * region between pos_start and pos-1 and replace
360 * the non-ram page at pos with the zero page.
361 */
362 if (pos > pos_start) {
363 /* Remap continuous region */
364 map_size = (pos - pos_start) << PAGE_SHIFT;
365 if (remap_oldmem_pfn_range(vma, from + len,
366 pos_start, map_size,
367 prot))
368 goto fail;
369 len += map_size;
370 }
371 /* Remap the zero page */
372 if (remap_oldmem_pfn_range(vma, from + len,
373 zeropage_pfn,
374 PAGE_SIZE, prot))
375 goto fail;
376 len += PAGE_SIZE;
377 pos_start = pos + 1;
378 }
379 }
380 if (pos > pos_start) {
381 /* Remap the rest */
382 map_size = (pos - pos_start) << PAGE_SHIFT;
383 if (remap_oldmem_pfn_range(vma, from + len, pos_start,
384 map_size, prot))
385 goto fail;
386 }
387 return 0;
388 fail:
389 do_munmap(vma->vm_mm, from, len);
390 return -EAGAIN;
391 }
392
393 static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
394 unsigned long from, unsigned long pfn,
395 unsigned long size, pgprot_t prot)
396 {
397 /*
398 * Check if oldmem_pfn_is_ram was registered to avoid
399 * looping over all pages without a reason.
400 */
401 if (oldmem_pfn_is_ram)
402 return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
403 else
404 return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
405 }
406
407 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
408 {
409 size_t size = vma->vm_end - vma->vm_start;
410 u64 start, end, len, tsz;
411 struct vmcore *m;
412
413 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
414 end = start + size;
415
416 if (size > vmcore_size || end > vmcore_size)
417 return -EINVAL;
418
419 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
420 return -EPERM;
421
422 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
423 vma->vm_flags |= VM_MIXEDMAP;
424 vma->vm_ops = &vmcore_mmap_ops;
425
426 len = 0;
427
428 if (start < elfcorebuf_sz) {
429 u64 pfn;
430
431 tsz = min(elfcorebuf_sz - (size_t)start, size);
432 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
433 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
434 vma->vm_page_prot))
435 return -EAGAIN;
436 size -= tsz;
437 start += tsz;
438 len += tsz;
439
440 if (size == 0)
441 return 0;
442 }
443
444 if (start < elfcorebuf_sz + elfnotes_sz) {
445 void *kaddr;
446
447 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
448 kaddr = elfnotes_buf + start - elfcorebuf_sz;
449 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
450 kaddr, tsz))
451 goto fail;
452 size -= tsz;
453 start += tsz;
454 len += tsz;
455
456 if (size == 0)
457 return 0;
458 }
459
460 list_for_each_entry(m, &vmcore_list, list) {
461 if (start < m->offset + m->size) {
462 u64 paddr = 0;
463
464 tsz = min_t(size_t, m->offset + m->size - start, size);
465 paddr = m->paddr + start - m->offset;
466 if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
467 paddr >> PAGE_SHIFT, tsz,
468 vma->vm_page_prot))
469 goto fail;
470 size -= tsz;
471 start += tsz;
472 len += tsz;
473
474 if (size == 0)
475 return 0;
476 }
477 }
478
479 return 0;
480 fail:
481 do_munmap(vma->vm_mm, vma->vm_start, len);
482 return -EAGAIN;
483 }
484 #else
485 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
486 {
487 return -ENOSYS;
488 }
489 #endif
490
491 static const struct file_operations proc_vmcore_operations = {
492 .read = read_vmcore,
493 .llseek = default_llseek,
494 .mmap = mmap_vmcore,
495 };
496
497 static struct vmcore* __init get_new_element(void)
498 {
499 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
500 }
501
502 static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
503 struct list_head *vc_list)
504 {
505 u64 size;
506 struct vmcore *m;
507
508 size = elfsz + elfnotesegsz;
509 list_for_each_entry(m, vc_list, list) {
510 size += m->size;
511 }
512 return size;
513 }
514
515 /**
516 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
517 *
518 * @ehdr_ptr: ELF header
519 *
520 * This function updates p_memsz member of each PT_NOTE entry in the
521 * program header table pointed to by @ehdr_ptr to real size of ELF
522 * note segment.
523 */
524 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
525 {
526 int i, rc=0;
527 Elf64_Phdr *phdr_ptr;
528 Elf64_Nhdr *nhdr_ptr;
529
530 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
531 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
532 void *notes_section;
533 u64 offset, max_sz, sz, real_sz = 0;
534 if (phdr_ptr->p_type != PT_NOTE)
535 continue;
536 max_sz = phdr_ptr->p_memsz;
537 offset = phdr_ptr->p_offset;
538 notes_section = kmalloc(max_sz, GFP_KERNEL);
539 if (!notes_section)
540 return -ENOMEM;
541 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
542 if (rc < 0) {
543 kfree(notes_section);
544 return rc;
545 }
546 nhdr_ptr = notes_section;
547 while (nhdr_ptr->n_namesz != 0) {
548 sz = sizeof(Elf64_Nhdr) +
549 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
550 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
551 if ((real_sz + sz) > max_sz) {
552 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
553 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
554 break;
555 }
556 real_sz += sz;
557 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
558 }
559 kfree(notes_section);
560 phdr_ptr->p_memsz = real_sz;
561 if (real_sz == 0) {
562 pr_warn("Warning: Zero PT_NOTE entries found\n");
563 }
564 }
565
566 return 0;
567 }
568
569 /**
570 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
571 * headers and sum of real size of their ELF note segment headers and
572 * data.
573 *
574 * @ehdr_ptr: ELF header
575 * @nr_ptnote: buffer for the number of PT_NOTE program headers
576 * @sz_ptnote: buffer for size of unique PT_NOTE program header
577 *
578 * This function is used to merge multiple PT_NOTE program headers
579 * into a unique single one. The resulting unique entry will have
580 * @sz_ptnote in its phdr->p_mem.
581 *
582 * It is assumed that program headers with PT_NOTE type pointed to by
583 * @ehdr_ptr has already been updated by update_note_header_size_elf64
584 * and each of PT_NOTE program headers has actual ELF note segment
585 * size in its p_memsz member.
586 */
587 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
588 int *nr_ptnote, u64 *sz_ptnote)
589 {
590 int i;
591 Elf64_Phdr *phdr_ptr;
592
593 *nr_ptnote = *sz_ptnote = 0;
594
595 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
596 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
597 if (phdr_ptr->p_type != PT_NOTE)
598 continue;
599 *nr_ptnote += 1;
600 *sz_ptnote += phdr_ptr->p_memsz;
601 }
602
603 return 0;
604 }
605
606 /**
607 * copy_notes_elf64 - copy ELF note segments in a given buffer
608 *
609 * @ehdr_ptr: ELF header
610 * @notes_buf: buffer into which ELF note segments are copied
611 *
612 * This function is used to copy ELF note segment in the 1st kernel
613 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
614 * size of the buffer @notes_buf is equal to or larger than sum of the
615 * real ELF note segment headers and data.
616 *
617 * It is assumed that program headers with PT_NOTE type pointed to by
618 * @ehdr_ptr has already been updated by update_note_header_size_elf64
619 * and each of PT_NOTE program headers has actual ELF note segment
620 * size in its p_memsz member.
621 */
622 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
623 {
624 int i, rc=0;
625 Elf64_Phdr *phdr_ptr;
626
627 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
628
629 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
630 u64 offset;
631 if (phdr_ptr->p_type != PT_NOTE)
632 continue;
633 offset = phdr_ptr->p_offset;
634 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
635 &offset);
636 if (rc < 0)
637 return rc;
638 notes_buf += phdr_ptr->p_memsz;
639 }
640
641 return 0;
642 }
643
644 /* Merges all the PT_NOTE headers into one. */
645 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
646 char **notes_buf, size_t *notes_sz)
647 {
648 int i, nr_ptnote=0, rc=0;
649 char *tmp;
650 Elf64_Ehdr *ehdr_ptr;
651 Elf64_Phdr phdr;
652 u64 phdr_sz = 0, note_off;
653
654 ehdr_ptr = (Elf64_Ehdr *)elfptr;
655
656 rc = update_note_header_size_elf64(ehdr_ptr);
657 if (rc < 0)
658 return rc;
659
660 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
661 if (rc < 0)
662 return rc;
663
664 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
665 *notes_buf = alloc_elfnotes_buf(*notes_sz);
666 if (!*notes_buf)
667 return -ENOMEM;
668
669 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
670 if (rc < 0)
671 return rc;
672
673 /* Prepare merged PT_NOTE program header. */
674 phdr.p_type = PT_NOTE;
675 phdr.p_flags = 0;
676 note_off = sizeof(Elf64_Ehdr) +
677 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
678 phdr.p_offset = roundup(note_off, PAGE_SIZE);
679 phdr.p_vaddr = phdr.p_paddr = 0;
680 phdr.p_filesz = phdr.p_memsz = phdr_sz;
681 phdr.p_align = 0;
682
683 /* Add merged PT_NOTE program header*/
684 tmp = elfptr + sizeof(Elf64_Ehdr);
685 memcpy(tmp, &phdr, sizeof(phdr));
686 tmp += sizeof(phdr);
687
688 /* Remove unwanted PT_NOTE program headers. */
689 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
690 *elfsz = *elfsz - i;
691 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
692 memset(elfptr + *elfsz, 0, i);
693 *elfsz = roundup(*elfsz, PAGE_SIZE);
694
695 /* Modify e_phnum to reflect merged headers. */
696 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
697
698 return 0;
699 }
700
701 /**
702 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
703 *
704 * @ehdr_ptr: ELF header
705 *
706 * This function updates p_memsz member of each PT_NOTE entry in the
707 * program header table pointed to by @ehdr_ptr to real size of ELF
708 * note segment.
709 */
710 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
711 {
712 int i, rc=0;
713 Elf32_Phdr *phdr_ptr;
714 Elf32_Nhdr *nhdr_ptr;
715
716 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
717 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
718 void *notes_section;
719 u64 offset, max_sz, sz, real_sz = 0;
720 if (phdr_ptr->p_type != PT_NOTE)
721 continue;
722 max_sz = phdr_ptr->p_memsz;
723 offset = phdr_ptr->p_offset;
724 notes_section = kmalloc(max_sz, GFP_KERNEL);
725 if (!notes_section)
726 return -ENOMEM;
727 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
728 if (rc < 0) {
729 kfree(notes_section);
730 return rc;
731 }
732 nhdr_ptr = notes_section;
733 while (nhdr_ptr->n_namesz != 0) {
734 sz = sizeof(Elf32_Nhdr) +
735 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
736 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
737 if ((real_sz + sz) > max_sz) {
738 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
739 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
740 break;
741 }
742 real_sz += sz;
743 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
744 }
745 kfree(notes_section);
746 phdr_ptr->p_memsz = real_sz;
747 if (real_sz == 0) {
748 pr_warn("Warning: Zero PT_NOTE entries found\n");
749 }
750 }
751
752 return 0;
753 }
754
755 /**
756 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
757 * headers and sum of real size of their ELF note segment headers and
758 * data.
759 *
760 * @ehdr_ptr: ELF header
761 * @nr_ptnote: buffer for the number of PT_NOTE program headers
762 * @sz_ptnote: buffer for size of unique PT_NOTE program header
763 *
764 * This function is used to merge multiple PT_NOTE program headers
765 * into a unique single one. The resulting unique entry will have
766 * @sz_ptnote in its phdr->p_mem.
767 *
768 * It is assumed that program headers with PT_NOTE type pointed to by
769 * @ehdr_ptr has already been updated by update_note_header_size_elf32
770 * and each of PT_NOTE program headers has actual ELF note segment
771 * size in its p_memsz member.
772 */
773 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
774 int *nr_ptnote, u64 *sz_ptnote)
775 {
776 int i;
777 Elf32_Phdr *phdr_ptr;
778
779 *nr_ptnote = *sz_ptnote = 0;
780
781 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
782 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
783 if (phdr_ptr->p_type != PT_NOTE)
784 continue;
785 *nr_ptnote += 1;
786 *sz_ptnote += phdr_ptr->p_memsz;
787 }
788
789 return 0;
790 }
791
792 /**
793 * copy_notes_elf32 - copy ELF note segments in a given buffer
794 *
795 * @ehdr_ptr: ELF header
796 * @notes_buf: buffer into which ELF note segments are copied
797 *
798 * This function is used to copy ELF note segment in the 1st kernel
799 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
800 * size of the buffer @notes_buf is equal to or larger than sum of the
801 * real ELF note segment headers and data.
802 *
803 * It is assumed that program headers with PT_NOTE type pointed to by
804 * @ehdr_ptr has already been updated by update_note_header_size_elf32
805 * and each of PT_NOTE program headers has actual ELF note segment
806 * size in its p_memsz member.
807 */
808 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
809 {
810 int i, rc=0;
811 Elf32_Phdr *phdr_ptr;
812
813 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
814
815 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
816 u64 offset;
817 if (phdr_ptr->p_type != PT_NOTE)
818 continue;
819 offset = phdr_ptr->p_offset;
820 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
821 &offset);
822 if (rc < 0)
823 return rc;
824 notes_buf += phdr_ptr->p_memsz;
825 }
826
827 return 0;
828 }
829
830 /* Merges all the PT_NOTE headers into one. */
831 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
832 char **notes_buf, size_t *notes_sz)
833 {
834 int i, nr_ptnote=0, rc=0;
835 char *tmp;
836 Elf32_Ehdr *ehdr_ptr;
837 Elf32_Phdr phdr;
838 u64 phdr_sz = 0, note_off;
839
840 ehdr_ptr = (Elf32_Ehdr *)elfptr;
841
842 rc = update_note_header_size_elf32(ehdr_ptr);
843 if (rc < 0)
844 return rc;
845
846 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
847 if (rc < 0)
848 return rc;
849
850 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
851 *notes_buf = alloc_elfnotes_buf(*notes_sz);
852 if (!*notes_buf)
853 return -ENOMEM;
854
855 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
856 if (rc < 0)
857 return rc;
858
859 /* Prepare merged PT_NOTE program header. */
860 phdr.p_type = PT_NOTE;
861 phdr.p_flags = 0;
862 note_off = sizeof(Elf32_Ehdr) +
863 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
864 phdr.p_offset = roundup(note_off, PAGE_SIZE);
865 phdr.p_vaddr = phdr.p_paddr = 0;
866 phdr.p_filesz = phdr.p_memsz = phdr_sz;
867 phdr.p_align = 0;
868
869 /* Add merged PT_NOTE program header*/
870 tmp = elfptr + sizeof(Elf32_Ehdr);
871 memcpy(tmp, &phdr, sizeof(phdr));
872 tmp += sizeof(phdr);
873
874 /* Remove unwanted PT_NOTE program headers. */
875 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
876 *elfsz = *elfsz - i;
877 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
878 memset(elfptr + *elfsz, 0, i);
879 *elfsz = roundup(*elfsz, PAGE_SIZE);
880
881 /* Modify e_phnum to reflect merged headers. */
882 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
883
884 return 0;
885 }
886
887 /* Add memory chunks represented by program headers to vmcore list. Also update
888 * the new offset fields of exported program headers. */
889 static int __init process_ptload_program_headers_elf64(char *elfptr,
890 size_t elfsz,
891 size_t elfnotes_sz,
892 struct list_head *vc_list)
893 {
894 int i;
895 Elf64_Ehdr *ehdr_ptr;
896 Elf64_Phdr *phdr_ptr;
897 loff_t vmcore_off;
898 struct vmcore *new;
899
900 ehdr_ptr = (Elf64_Ehdr *)elfptr;
901 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
902
903 /* Skip Elf header, program headers and Elf note segment. */
904 vmcore_off = elfsz + elfnotes_sz;
905
906 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
907 u64 paddr, start, end, size;
908
909 if (phdr_ptr->p_type != PT_LOAD)
910 continue;
911
912 paddr = phdr_ptr->p_offset;
913 start = rounddown(paddr, PAGE_SIZE);
914 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
915 size = end - start;
916
917 /* Add this contiguous chunk of memory to vmcore list.*/
918 new = get_new_element();
919 if (!new)
920 return -ENOMEM;
921 new->paddr = start;
922 new->size = size;
923 list_add_tail(&new->list, vc_list);
924
925 /* Update the program header offset. */
926 phdr_ptr->p_offset = vmcore_off + (paddr - start);
927 vmcore_off = vmcore_off + size;
928 }
929 return 0;
930 }
931
932 static int __init process_ptload_program_headers_elf32(char *elfptr,
933 size_t elfsz,
934 size_t elfnotes_sz,
935 struct list_head *vc_list)
936 {
937 int i;
938 Elf32_Ehdr *ehdr_ptr;
939 Elf32_Phdr *phdr_ptr;
940 loff_t vmcore_off;
941 struct vmcore *new;
942
943 ehdr_ptr = (Elf32_Ehdr *)elfptr;
944 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
945
946 /* Skip Elf header, program headers and Elf note segment. */
947 vmcore_off = elfsz + elfnotes_sz;
948
949 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
950 u64 paddr, start, end, size;
951
952 if (phdr_ptr->p_type != PT_LOAD)
953 continue;
954
955 paddr = phdr_ptr->p_offset;
956 start = rounddown(paddr, PAGE_SIZE);
957 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
958 size = end - start;
959
960 /* Add this contiguous chunk of memory to vmcore list.*/
961 new = get_new_element();
962 if (!new)
963 return -ENOMEM;
964 new->paddr = start;
965 new->size = size;
966 list_add_tail(&new->list, vc_list);
967
968 /* Update the program header offset */
969 phdr_ptr->p_offset = vmcore_off + (paddr - start);
970 vmcore_off = vmcore_off + size;
971 }
972 return 0;
973 }
974
975 /* Sets offset fields of vmcore elements. */
976 static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
977 struct list_head *vc_list)
978 {
979 loff_t vmcore_off;
980 struct vmcore *m;
981
982 /* Skip Elf header, program headers and Elf note segment. */
983 vmcore_off = elfsz + elfnotes_sz;
984
985 list_for_each_entry(m, vc_list, list) {
986 m->offset = vmcore_off;
987 vmcore_off += m->size;
988 }
989 }
990
991 static void free_elfcorebuf(void)
992 {
993 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
994 elfcorebuf = NULL;
995 vfree(elfnotes_buf);
996 elfnotes_buf = NULL;
997 }
998
999 static int __init parse_crash_elf64_headers(void)
1000 {
1001 int rc=0;
1002 Elf64_Ehdr ehdr;
1003 u64 addr;
1004
1005 addr = elfcorehdr_addr;
1006
1007 /* Read Elf header */
1008 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1009 if (rc < 0)
1010 return rc;
1011
1012 /* Do some basic Verification. */
1013 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1014 (ehdr.e_type != ET_CORE) ||
1015 !vmcore_elf64_check_arch(&ehdr) ||
1016 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1017 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1018 ehdr.e_version != EV_CURRENT ||
1019 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1020 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1021 ehdr.e_phnum == 0) {
1022 pr_warn("Warning: Core image elf header is not sane\n");
1023 return -EINVAL;
1024 }
1025
1026 /* Read in all elf headers. */
1027 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1028 ehdr.e_phnum * sizeof(Elf64_Phdr);
1029 elfcorebuf_sz = elfcorebuf_sz_orig;
1030 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1031 get_order(elfcorebuf_sz_orig));
1032 if (!elfcorebuf)
1033 return -ENOMEM;
1034 addr = elfcorehdr_addr;
1035 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1036 if (rc < 0)
1037 goto fail;
1038
1039 /* Merge all PT_NOTE headers into one. */
1040 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1041 &elfnotes_buf, &elfnotes_sz);
1042 if (rc)
1043 goto fail;
1044 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1045 elfnotes_sz, &vmcore_list);
1046 if (rc)
1047 goto fail;
1048 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1049 return 0;
1050 fail:
1051 free_elfcorebuf();
1052 return rc;
1053 }
1054
1055 static int __init parse_crash_elf32_headers(void)
1056 {
1057 int rc=0;
1058 Elf32_Ehdr ehdr;
1059 u64 addr;
1060
1061 addr = elfcorehdr_addr;
1062
1063 /* Read Elf header */
1064 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1065 if (rc < 0)
1066 return rc;
1067
1068 /* Do some basic Verification. */
1069 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1070 (ehdr.e_type != ET_CORE) ||
1071 !elf_check_arch(&ehdr) ||
1072 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1073 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1074 ehdr.e_version != EV_CURRENT ||
1075 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1076 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1077 ehdr.e_phnum == 0) {
1078 pr_warn("Warning: Core image elf header is not sane\n");
1079 return -EINVAL;
1080 }
1081
1082 /* Read in all elf headers. */
1083 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1084 elfcorebuf_sz = elfcorebuf_sz_orig;
1085 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1086 get_order(elfcorebuf_sz_orig));
1087 if (!elfcorebuf)
1088 return -ENOMEM;
1089 addr = elfcorehdr_addr;
1090 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1091 if (rc < 0)
1092 goto fail;
1093
1094 /* Merge all PT_NOTE headers into one. */
1095 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1096 &elfnotes_buf, &elfnotes_sz);
1097 if (rc)
1098 goto fail;
1099 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1100 elfnotes_sz, &vmcore_list);
1101 if (rc)
1102 goto fail;
1103 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1104 return 0;
1105 fail:
1106 free_elfcorebuf();
1107 return rc;
1108 }
1109
1110 static int __init parse_crash_elf_headers(void)
1111 {
1112 unsigned char e_ident[EI_NIDENT];
1113 u64 addr;
1114 int rc=0;
1115
1116 addr = elfcorehdr_addr;
1117 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1118 if (rc < 0)
1119 return rc;
1120 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1121 pr_warn("Warning: Core image elf header not found\n");
1122 return -EINVAL;
1123 }
1124
1125 if (e_ident[EI_CLASS] == ELFCLASS64) {
1126 rc = parse_crash_elf64_headers();
1127 if (rc)
1128 return rc;
1129 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1130 rc = parse_crash_elf32_headers();
1131 if (rc)
1132 return rc;
1133 } else {
1134 pr_warn("Warning: Core image elf header is not sane\n");
1135 return -EINVAL;
1136 }
1137
1138 /* Determine vmcore size. */
1139 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1140 &vmcore_list);
1141
1142 return 0;
1143 }
1144
1145 /* Init function for vmcore module. */
1146 static int __init vmcore_init(void)
1147 {
1148 int rc = 0;
1149
1150 /* Allow architectures to allocate ELF header in 2nd kernel */
1151 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1152 if (rc)
1153 return rc;
1154 /*
1155 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1156 * then capture the dump.
1157 */
1158 if (!(is_vmcore_usable()))
1159 return rc;
1160 rc = parse_crash_elf_headers();
1161 if (rc) {
1162 pr_warn("Kdump: vmcore not initialized\n");
1163 return rc;
1164 }
1165 elfcorehdr_free(elfcorehdr_addr);
1166 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1167
1168 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1169 if (proc_vmcore)
1170 proc_vmcore->size = vmcore_size;
1171 return 0;
1172 }
1173 fs_initcall(vmcore_init);
1174
1175 /* Cleanup function for vmcore module. */
1176 void vmcore_cleanup(void)
1177 {
1178 struct list_head *pos, *next;
1179
1180 if (proc_vmcore) {
1181 proc_remove(proc_vmcore);
1182 proc_vmcore = NULL;
1183 }
1184
1185 /* clear the vmcore list. */
1186 list_for_each_safe(pos, next, &vmcore_list) {
1187 struct vmcore *m;
1188
1189 m = list_entry(pos, struct vmcore, list);
1190 list_del(&m->list);
1191 kfree(m);
1192 }
1193 free_elfcorebuf();
1194 }
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