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/mutex.h>
24 #include <linux/vmalloc.h>
25 #include <linux/pagemap.h>
26 #include <linux/uaccess.h>
27 #include <asm/io.h>
28 #include "internal.h"
29
30 /* List representing chunks of contiguous memory areas and their offsets in
31 * vmcore file.
32 */
33 static LIST_HEAD(vmcore_list);
34
35 /* Stores the pointer to the buffer containing kernel elf core headers. */
36 static char *elfcorebuf;
37 static size_t elfcorebuf_sz;
38 static size_t elfcorebuf_sz_orig;
39
40 static char *elfnotes_buf;
41 static size_t elfnotes_sz;
42 /* Size of all notes minus the device dump notes */
43 static size_t elfnotes_orig_sz;
44
45 /* Total size of vmcore file. */
46 static u64 vmcore_size;
47
48 static struct proc_dir_entry *proc_vmcore;
49
50 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
51 /* Device Dump list and mutex to synchronize access to list */
52 static LIST_HEAD(vmcoredd_list);
53 static DEFINE_MUTEX(vmcoredd_mutex);
54 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
55
56 /* Device Dump Size */
57 static size_t vmcoredd_orig_sz;
58
59 /*
60 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
61 * The called function has to take care of module refcounting.
62 */
63 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
64
register_oldmem_pfn_is_ram(int (* fn)(unsigned long pfn))65 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
66 {
67 if (oldmem_pfn_is_ram)
68 return -EBUSY;
69 oldmem_pfn_is_ram = fn;
70 return 0;
71 }
72 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
73
unregister_oldmem_pfn_is_ram(void)74 void unregister_oldmem_pfn_is_ram(void)
75 {
76 oldmem_pfn_is_ram = NULL;
77 wmb();
78 }
79 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
80
pfn_is_ram(unsigned long pfn)81 static int pfn_is_ram(unsigned long pfn)
82 {
83 int (*fn)(unsigned long pfn);
84 /* pfn is ram unless fn() checks pagetype */
85 int ret = 1;
86
87 /*
88 * Ask hypervisor if the pfn is really ram.
89 * A ballooned page contains no data and reading from such a page
90 * will cause high load in the hypervisor.
91 */
92 fn = oldmem_pfn_is_ram;
93 if (fn)
94 ret = fn(pfn);
95
96 return ret;
97 }
98
99 /* Reads a page from the oldmem device from given offset. */
read_from_oldmem(char * buf,size_t count,u64 * ppos,int userbuf)100 static ssize_t read_from_oldmem(char *buf, size_t count,
101 u64 *ppos, int userbuf)
102 {
103 unsigned long pfn, offset;
104 size_t nr_bytes;
105 ssize_t read = 0, tmp;
106
107 if (!count)
108 return 0;
109
110 offset = (unsigned long)(*ppos % PAGE_SIZE);
111 pfn = (unsigned long)(*ppos / PAGE_SIZE);
112
113 do {
114 if (count > (PAGE_SIZE - offset))
115 nr_bytes = PAGE_SIZE - offset;
116 else
117 nr_bytes = count;
118
119 /* If pfn is not ram, return zeros for sparse dump files */
120 if (pfn_is_ram(pfn) == 0) {
121 tmp = 0;
122 if (!userbuf)
123 memset(buf, 0, nr_bytes);
124 else if (clear_user(buf, nr_bytes))
125 tmp = -EFAULT;
126 } else {
127 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
128 offset, userbuf);
129 }
130 if (tmp < 0)
131 return tmp;
132
133 *ppos += nr_bytes;
134 count -= nr_bytes;
135 buf += nr_bytes;
136 read += nr_bytes;
137 ++pfn;
138 offset = 0;
139 } while (count);
140
141 return read;
142 }
143
144 /*
145 * Architectures may override this function to allocate ELF header in 2nd kernel
146 */
elfcorehdr_alloc(unsigned long long * addr,unsigned long long * size)147 int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
148 {
149 return 0;
150 }
151
152 /*
153 * Architectures may override this function to free header
154 */
elfcorehdr_free(unsigned long long addr)155 void __weak elfcorehdr_free(unsigned long long addr)
156 {}
157
158 /*
159 * Architectures may override this function to read from ELF header
160 */
elfcorehdr_read(char * buf,size_t count,u64 * ppos)161 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
162 {
163 return read_from_oldmem(buf, count, ppos, 0);
164 }
165
166 /*
167 * Architectures may override this function to read from notes sections
168 */
elfcorehdr_read_notes(char * buf,size_t count,u64 * ppos)169 ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
170 {
171 return read_from_oldmem(buf, count, ppos, 0);
172 }
173
174 /*
175 * Architectures may override this function to map oldmem
176 */
remap_oldmem_pfn_range(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)177 int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
178 unsigned long from, unsigned long pfn,
179 unsigned long size, pgprot_t prot)
180 {
181 return remap_pfn_range(vma, from, pfn, size, prot);
182 }
183
184 /*
185 * Architectures which support memory encryption override this.
186 */
187 ssize_t __weak
copy_oldmem_page_encrypted(unsigned long pfn,char * buf,size_t csize,unsigned long offset,int userbuf)188 copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
189 unsigned long offset, int userbuf)
190 {
191 return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
192 }
193
194 /*
195 * Copy to either kernel or user space
196 */
copy_to(void * target,void * src,size_t size,int userbuf)197 static int copy_to(void *target, void *src, size_t size, int userbuf)
198 {
199 if (userbuf) {
200 if (copy_to_user((char __user *) target, src, size))
201 return -EFAULT;
202 } else {
203 memcpy(target, src, size);
204 }
205 return 0;
206 }
207
208 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
vmcoredd_copy_dumps(void * dst,u64 start,size_t size,int userbuf)209 static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
210 {
211 struct vmcoredd_node *dump;
212 u64 offset = 0;
213 int ret = 0;
214 size_t tsz;
215 char *buf;
216
217 mutex_lock(&vmcoredd_mutex);
218 list_for_each_entry(dump, &vmcoredd_list, list) {
219 if (start < offset + dump->size) {
220 tsz = min(offset + (u64)dump->size - start, (u64)size);
221 buf = dump->buf + start - offset;
222 if (copy_to(dst, buf, tsz, userbuf)) {
223 ret = -EFAULT;
224 goto out_unlock;
225 }
226
227 size -= tsz;
228 start += tsz;
229 dst += tsz;
230
231 /* Leave now if buffer filled already */
232 if (!size)
233 goto out_unlock;
234 }
235 offset += dump->size;
236 }
237
238 out_unlock:
239 mutex_unlock(&vmcoredd_mutex);
240 return ret;
241 }
242
243 #ifdef CONFIG_MMU
vmcoredd_mmap_dumps(struct vm_area_struct * vma,unsigned long dst,u64 start,size_t size)244 static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
245 u64 start, size_t size)
246 {
247 struct vmcoredd_node *dump;
248 u64 offset = 0;
249 int ret = 0;
250 size_t tsz;
251 char *buf;
252
253 mutex_lock(&vmcoredd_mutex);
254 list_for_each_entry(dump, &vmcoredd_list, list) {
255 if (start < offset + dump->size) {
256 tsz = min(offset + (u64)dump->size - start, (u64)size);
257 buf = dump->buf + start - offset;
258 if (remap_vmalloc_range_partial(vma, dst, buf, 0,
259 tsz)) {
260 ret = -EFAULT;
261 goto out_unlock;
262 }
263
264 size -= tsz;
265 start += tsz;
266 dst += tsz;
267
268 /* Leave now if buffer filled already */
269 if (!size)
270 goto out_unlock;
271 }
272 offset += dump->size;
273 }
274
275 out_unlock:
276 mutex_unlock(&vmcoredd_mutex);
277 return ret;
278 }
279 #endif /* CONFIG_MMU */
280 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
281
282 /* Read from the ELF header and then the crash dump. On error, negative value is
283 * returned otherwise number of bytes read are returned.
284 */
__read_vmcore(char * buffer,size_t buflen,loff_t * fpos,int userbuf)285 static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
286 int userbuf)
287 {
288 ssize_t acc = 0, tmp;
289 size_t tsz;
290 u64 start;
291 struct vmcore *m = NULL;
292
293 if (buflen == 0 || *fpos >= vmcore_size)
294 return 0;
295
296 /* trim buflen to not go beyond EOF */
297 if (buflen > vmcore_size - *fpos)
298 buflen = vmcore_size - *fpos;
299
300 /* Read ELF core header */
301 if (*fpos < elfcorebuf_sz) {
302 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
303 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
304 return -EFAULT;
305 buflen -= tsz;
306 *fpos += tsz;
307 buffer += tsz;
308 acc += tsz;
309
310 /* leave now if filled buffer already */
311 if (buflen == 0)
312 return acc;
313 }
314
315 /* Read Elf note segment */
316 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
317 void *kaddr;
318
319 /* We add device dumps before other elf notes because the
320 * other elf notes may not fill the elf notes buffer
321 * completely and we will end up with zero-filled data
322 * between the elf notes and the device dumps. Tools will
323 * then try to decode this zero-filled data as valid notes
324 * and we don't want that. Hence, adding device dumps before
325 * the other elf notes ensure that zero-filled data can be
326 * avoided.
327 */
328 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
329 /* Read device dumps */
330 if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
331 tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
332 (size_t)*fpos, buflen);
333 start = *fpos - elfcorebuf_sz;
334 if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
335 return -EFAULT;
336
337 buflen -= tsz;
338 *fpos += tsz;
339 buffer += tsz;
340 acc += tsz;
341
342 /* leave now if filled buffer already */
343 if (!buflen)
344 return acc;
345 }
346 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
347
348 /* Read remaining elf notes */
349 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
350 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
351 if (copy_to(buffer, kaddr, tsz, userbuf))
352 return -EFAULT;
353
354 buflen -= tsz;
355 *fpos += tsz;
356 buffer += tsz;
357 acc += tsz;
358
359 /* leave now if filled buffer already */
360 if (buflen == 0)
361 return acc;
362 }
363
364 list_for_each_entry(m, &vmcore_list, list) {
365 if (*fpos < m->offset + m->size) {
366 tsz = (size_t)min_t(unsigned long long,
367 m->offset + m->size - *fpos,
368 buflen);
369 start = m->paddr + *fpos - m->offset;
370 tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
371 if (tmp < 0)
372 return tmp;
373 buflen -= tsz;
374 *fpos += tsz;
375 buffer += tsz;
376 acc += tsz;
377
378 /* leave now if filled buffer already */
379 if (buflen == 0)
380 return acc;
381 }
382 }
383
384 return acc;
385 }
386
read_vmcore(struct file * file,char __user * buffer,size_t buflen,loff_t * fpos)387 static ssize_t read_vmcore(struct file *file, char __user *buffer,
388 size_t buflen, loff_t *fpos)
389 {
390 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
391 }
392
393 /*
394 * The vmcore fault handler uses the page cache and fills data using the
395 * standard __vmcore_read() function.
396 *
397 * On s390 the fault handler is used for memory regions that can't be mapped
398 * directly with remap_pfn_range().
399 */
mmap_vmcore_fault(struct vm_fault * vmf)400 static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
401 {
402 #ifdef CONFIG_S390
403 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
404 pgoff_t index = vmf->pgoff;
405 struct page *page;
406 loff_t offset;
407 char *buf;
408 int rc;
409
410 page = find_or_create_page(mapping, index, GFP_KERNEL);
411 if (!page)
412 return VM_FAULT_OOM;
413 if (!PageUptodate(page)) {
414 offset = (loff_t) index << PAGE_SHIFT;
415 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
416 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
417 if (rc < 0) {
418 unlock_page(page);
419 put_page(page);
420 return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
421 }
422 SetPageUptodate(page);
423 }
424 unlock_page(page);
425 vmf->page = page;
426 return 0;
427 #else
428 return VM_FAULT_SIGBUS;
429 #endif
430 }
431
432 static const struct vm_operations_struct vmcore_mmap_ops = {
433 .fault = mmap_vmcore_fault,
434 };
435
436 /**
437 * vmcore_alloc_buf - allocate buffer in vmalloc memory
438 * @sizez: size of buffer
439 *
440 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
441 * the buffer to user-space by means of remap_vmalloc_range().
442 *
443 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
444 * disabled and there's no need to allow users to mmap the buffer.
445 */
vmcore_alloc_buf(size_t size)446 static inline char *vmcore_alloc_buf(size_t size)
447 {
448 #ifdef CONFIG_MMU
449 return vmalloc_user(size);
450 #else
451 return vzalloc(size);
452 #endif
453 }
454
455 /*
456 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
457 * essential for mmap_vmcore() in order to map physically
458 * non-contiguous objects (ELF header, ELF note segment and memory
459 * regions in the 1st kernel pointed to by PT_LOAD entries) into
460 * virtually contiguous user-space in ELF layout.
461 */
462 #ifdef CONFIG_MMU
463 /*
464 * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
465 * reported as not being ram with the zero page.
466 *
467 * @vma: vm_area_struct describing requested mapping
468 * @from: start remapping from
469 * @pfn: page frame number to start remapping to
470 * @size: remapping size
471 * @prot: protection bits
472 *
473 * Returns zero on success, -EAGAIN on failure.
474 */
remap_oldmem_pfn_checked(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)475 static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
476 unsigned long from, unsigned long pfn,
477 unsigned long size, pgprot_t prot)
478 {
479 unsigned long map_size;
480 unsigned long pos_start, pos_end, pos;
481 unsigned long zeropage_pfn = my_zero_pfn(0);
482 size_t len = 0;
483
484 pos_start = pfn;
485 pos_end = pfn + (size >> PAGE_SHIFT);
486
487 for (pos = pos_start; pos < pos_end; ++pos) {
488 if (!pfn_is_ram(pos)) {
489 /*
490 * We hit a page which is not ram. Remap the continuous
491 * region between pos_start and pos-1 and replace
492 * the non-ram page at pos with the zero page.
493 */
494 if (pos > pos_start) {
495 /* Remap continuous region */
496 map_size = (pos - pos_start) << PAGE_SHIFT;
497 if (remap_oldmem_pfn_range(vma, from + len,
498 pos_start, map_size,
499 prot))
500 goto fail;
501 len += map_size;
502 }
503 /* Remap the zero page */
504 if (remap_oldmem_pfn_range(vma, from + len,
505 zeropage_pfn,
506 PAGE_SIZE, prot))
507 goto fail;
508 len += PAGE_SIZE;
509 pos_start = pos + 1;
510 }
511 }
512 if (pos > pos_start) {
513 /* Remap the rest */
514 map_size = (pos - pos_start) << PAGE_SHIFT;
515 if (remap_oldmem_pfn_range(vma, from + len, pos_start,
516 map_size, prot))
517 goto fail;
518 }
519 return 0;
520 fail:
521 do_munmap(vma->vm_mm, from, len, NULL);
522 return -EAGAIN;
523 }
524
vmcore_remap_oldmem_pfn(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)525 static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
526 unsigned long from, unsigned long pfn,
527 unsigned long size, pgprot_t prot)
528 {
529 /*
530 * Check if oldmem_pfn_is_ram was registered to avoid
531 * looping over all pages without a reason.
532 */
533 if (oldmem_pfn_is_ram)
534 return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
535 else
536 return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
537 }
538
mmap_vmcore(struct file * file,struct vm_area_struct * vma)539 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
540 {
541 size_t size = vma->vm_end - vma->vm_start;
542 u64 start, end, len, tsz;
543 struct vmcore *m;
544
545 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
546 end = start + size;
547
548 if (size > vmcore_size || end > vmcore_size)
549 return -EINVAL;
550
551 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
552 return -EPERM;
553
554 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
555 vma->vm_flags |= VM_MIXEDMAP;
556 vma->vm_ops = &vmcore_mmap_ops;
557
558 len = 0;
559
560 if (start < elfcorebuf_sz) {
561 u64 pfn;
562
563 tsz = min(elfcorebuf_sz - (size_t)start, size);
564 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
565 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
566 vma->vm_page_prot))
567 return -EAGAIN;
568 size -= tsz;
569 start += tsz;
570 len += tsz;
571
572 if (size == 0)
573 return 0;
574 }
575
576 if (start < elfcorebuf_sz + elfnotes_sz) {
577 void *kaddr;
578
579 /* We add device dumps before other elf notes because the
580 * other elf notes may not fill the elf notes buffer
581 * completely and we will end up with zero-filled data
582 * between the elf notes and the device dumps. Tools will
583 * then try to decode this zero-filled data as valid notes
584 * and we don't want that. Hence, adding device dumps before
585 * the other elf notes ensure that zero-filled data can be
586 * avoided. This also ensures that the device dumps and
587 * other elf notes can be properly mmaped at page aligned
588 * address.
589 */
590 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
591 /* Read device dumps */
592 if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
593 u64 start_off;
594
595 tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
596 (size_t)start, size);
597 start_off = start - elfcorebuf_sz;
598 if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
599 start_off, tsz))
600 goto fail;
601
602 size -= tsz;
603 start += tsz;
604 len += tsz;
605
606 /* leave now if filled buffer already */
607 if (!size)
608 return 0;
609 }
610 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
611
612 /* Read remaining elf notes */
613 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
614 kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
615 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
616 kaddr, 0, tsz))
617 goto fail;
618
619 size -= tsz;
620 start += tsz;
621 len += tsz;
622
623 if (size == 0)
624 return 0;
625 }
626
627 list_for_each_entry(m, &vmcore_list, list) {
628 if (start < m->offset + m->size) {
629 u64 paddr = 0;
630
631 tsz = (size_t)min_t(unsigned long long,
632 m->offset + m->size - start, size);
633 paddr = m->paddr + start - m->offset;
634 if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
635 paddr >> PAGE_SHIFT, tsz,
636 vma->vm_page_prot))
637 goto fail;
638 size -= tsz;
639 start += tsz;
640 len += tsz;
641
642 if (size == 0)
643 return 0;
644 }
645 }
646
647 return 0;
648 fail:
649 do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
650 return -EAGAIN;
651 }
652 #else
mmap_vmcore(struct file * file,struct vm_area_struct * vma)653 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
654 {
655 return -ENOSYS;
656 }
657 #endif
658
659 static const struct file_operations proc_vmcore_operations = {
660 .read = read_vmcore,
661 .llseek = default_llseek,
662 .mmap = mmap_vmcore,
663 };
664
get_new_element(void)665 static struct vmcore* __init get_new_element(void)
666 {
667 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
668 }
669
get_vmcore_size(size_t elfsz,size_t elfnotesegsz,struct list_head * vc_list)670 static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
671 struct list_head *vc_list)
672 {
673 u64 size;
674 struct vmcore *m;
675
676 size = elfsz + elfnotesegsz;
677 list_for_each_entry(m, vc_list, list) {
678 size += m->size;
679 }
680 return size;
681 }
682
683 /**
684 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
685 *
686 * @ehdr_ptr: ELF header
687 *
688 * This function updates p_memsz member of each PT_NOTE entry in the
689 * program header table pointed to by @ehdr_ptr to real size of ELF
690 * note segment.
691 */
update_note_header_size_elf64(const Elf64_Ehdr * ehdr_ptr)692 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
693 {
694 int i, rc=0;
695 Elf64_Phdr *phdr_ptr;
696 Elf64_Nhdr *nhdr_ptr;
697
698 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
699 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
700 void *notes_section;
701 u64 offset, max_sz, sz, real_sz = 0;
702 if (phdr_ptr->p_type != PT_NOTE)
703 continue;
704 max_sz = phdr_ptr->p_memsz;
705 offset = phdr_ptr->p_offset;
706 notes_section = kmalloc(max_sz, GFP_KERNEL);
707 if (!notes_section)
708 return -ENOMEM;
709 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
710 if (rc < 0) {
711 kfree(notes_section);
712 return rc;
713 }
714 nhdr_ptr = notes_section;
715 while (nhdr_ptr->n_namesz != 0) {
716 sz = sizeof(Elf64_Nhdr) +
717 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
718 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
719 if ((real_sz + sz) > max_sz) {
720 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
721 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
722 break;
723 }
724 real_sz += sz;
725 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
726 }
727 kfree(notes_section);
728 phdr_ptr->p_memsz = real_sz;
729 if (real_sz == 0) {
730 pr_warn("Warning: Zero PT_NOTE entries found\n");
731 }
732 }
733
734 return 0;
735 }
736
737 /**
738 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
739 * headers and sum of real size of their ELF note segment headers and
740 * data.
741 *
742 * @ehdr_ptr: ELF header
743 * @nr_ptnote: buffer for the number of PT_NOTE program headers
744 * @sz_ptnote: buffer for size of unique PT_NOTE program header
745 *
746 * This function is used to merge multiple PT_NOTE program headers
747 * into a unique single one. The resulting unique entry will have
748 * @sz_ptnote in its phdr->p_mem.
749 *
750 * It is assumed that program headers with PT_NOTE type pointed to by
751 * @ehdr_ptr has already been updated by update_note_header_size_elf64
752 * and each of PT_NOTE program headers has actual ELF note segment
753 * size in its p_memsz member.
754 */
get_note_number_and_size_elf64(const Elf64_Ehdr * ehdr_ptr,int * nr_ptnote,u64 * sz_ptnote)755 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
756 int *nr_ptnote, u64 *sz_ptnote)
757 {
758 int i;
759 Elf64_Phdr *phdr_ptr;
760
761 *nr_ptnote = *sz_ptnote = 0;
762
763 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
764 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
765 if (phdr_ptr->p_type != PT_NOTE)
766 continue;
767 *nr_ptnote += 1;
768 *sz_ptnote += phdr_ptr->p_memsz;
769 }
770
771 return 0;
772 }
773
774 /**
775 * copy_notes_elf64 - copy ELF note segments in a given buffer
776 *
777 * @ehdr_ptr: ELF header
778 * @notes_buf: buffer into which ELF note segments are copied
779 *
780 * This function is used to copy ELF note segment in the 1st kernel
781 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
782 * size of the buffer @notes_buf is equal to or larger than sum of the
783 * real ELF note segment headers and data.
784 *
785 * It is assumed that program headers with PT_NOTE type pointed to by
786 * @ehdr_ptr has already been updated by update_note_header_size_elf64
787 * and each of PT_NOTE program headers has actual ELF note segment
788 * size in its p_memsz member.
789 */
copy_notes_elf64(const Elf64_Ehdr * ehdr_ptr,char * notes_buf)790 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
791 {
792 int i, rc=0;
793 Elf64_Phdr *phdr_ptr;
794
795 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
796
797 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
798 u64 offset;
799 if (phdr_ptr->p_type != PT_NOTE)
800 continue;
801 offset = phdr_ptr->p_offset;
802 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
803 &offset);
804 if (rc < 0)
805 return rc;
806 notes_buf += phdr_ptr->p_memsz;
807 }
808
809 return 0;
810 }
811
812 /* Merges all the PT_NOTE headers into one. */
merge_note_headers_elf64(char * elfptr,size_t * elfsz,char ** notes_buf,size_t * notes_sz)813 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
814 char **notes_buf, size_t *notes_sz)
815 {
816 int i, nr_ptnote=0, rc=0;
817 char *tmp;
818 Elf64_Ehdr *ehdr_ptr;
819 Elf64_Phdr phdr;
820 u64 phdr_sz = 0, note_off;
821
822 ehdr_ptr = (Elf64_Ehdr *)elfptr;
823
824 rc = update_note_header_size_elf64(ehdr_ptr);
825 if (rc < 0)
826 return rc;
827
828 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
829 if (rc < 0)
830 return rc;
831
832 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
833 *notes_buf = vmcore_alloc_buf(*notes_sz);
834 if (!*notes_buf)
835 return -ENOMEM;
836
837 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
838 if (rc < 0)
839 return rc;
840
841 /* Prepare merged PT_NOTE program header. */
842 phdr.p_type = PT_NOTE;
843 phdr.p_flags = 0;
844 note_off = sizeof(Elf64_Ehdr) +
845 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
846 phdr.p_offset = roundup(note_off, PAGE_SIZE);
847 phdr.p_vaddr = phdr.p_paddr = 0;
848 phdr.p_filesz = phdr.p_memsz = phdr_sz;
849 phdr.p_align = 0;
850
851 /* Add merged PT_NOTE program header*/
852 tmp = elfptr + sizeof(Elf64_Ehdr);
853 memcpy(tmp, &phdr, sizeof(phdr));
854 tmp += sizeof(phdr);
855
856 /* Remove unwanted PT_NOTE program headers. */
857 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
858 *elfsz = *elfsz - i;
859 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
860 memset(elfptr + *elfsz, 0, i);
861 *elfsz = roundup(*elfsz, PAGE_SIZE);
862
863 /* Modify e_phnum to reflect merged headers. */
864 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
865
866 /* Store the size of all notes. We need this to update the note
867 * header when the device dumps will be added.
868 */
869 elfnotes_orig_sz = phdr.p_memsz;
870
871 return 0;
872 }
873
874 /**
875 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
876 *
877 * @ehdr_ptr: ELF header
878 *
879 * This function updates p_memsz member of each PT_NOTE entry in the
880 * program header table pointed to by @ehdr_ptr to real size of ELF
881 * note segment.
882 */
update_note_header_size_elf32(const Elf32_Ehdr * ehdr_ptr)883 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
884 {
885 int i, rc=0;
886 Elf32_Phdr *phdr_ptr;
887 Elf32_Nhdr *nhdr_ptr;
888
889 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
890 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
891 void *notes_section;
892 u64 offset, max_sz, sz, real_sz = 0;
893 if (phdr_ptr->p_type != PT_NOTE)
894 continue;
895 max_sz = phdr_ptr->p_memsz;
896 offset = phdr_ptr->p_offset;
897 notes_section = kmalloc(max_sz, GFP_KERNEL);
898 if (!notes_section)
899 return -ENOMEM;
900 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
901 if (rc < 0) {
902 kfree(notes_section);
903 return rc;
904 }
905 nhdr_ptr = notes_section;
906 while (nhdr_ptr->n_namesz != 0) {
907 sz = sizeof(Elf32_Nhdr) +
908 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
909 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
910 if ((real_sz + sz) > max_sz) {
911 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
912 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
913 break;
914 }
915 real_sz += sz;
916 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
917 }
918 kfree(notes_section);
919 phdr_ptr->p_memsz = real_sz;
920 if (real_sz == 0) {
921 pr_warn("Warning: Zero PT_NOTE entries found\n");
922 }
923 }
924
925 return 0;
926 }
927
928 /**
929 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
930 * headers and sum of real size of their ELF note segment headers and
931 * data.
932 *
933 * @ehdr_ptr: ELF header
934 * @nr_ptnote: buffer for the number of PT_NOTE program headers
935 * @sz_ptnote: buffer for size of unique PT_NOTE program header
936 *
937 * This function is used to merge multiple PT_NOTE program headers
938 * into a unique single one. The resulting unique entry will have
939 * @sz_ptnote in its phdr->p_mem.
940 *
941 * It is assumed that program headers with PT_NOTE type pointed to by
942 * @ehdr_ptr has already been updated by update_note_header_size_elf32
943 * and each of PT_NOTE program headers has actual ELF note segment
944 * size in its p_memsz member.
945 */
get_note_number_and_size_elf32(const Elf32_Ehdr * ehdr_ptr,int * nr_ptnote,u64 * sz_ptnote)946 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
947 int *nr_ptnote, u64 *sz_ptnote)
948 {
949 int i;
950 Elf32_Phdr *phdr_ptr;
951
952 *nr_ptnote = *sz_ptnote = 0;
953
954 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
955 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
956 if (phdr_ptr->p_type != PT_NOTE)
957 continue;
958 *nr_ptnote += 1;
959 *sz_ptnote += phdr_ptr->p_memsz;
960 }
961
962 return 0;
963 }
964
965 /**
966 * copy_notes_elf32 - copy ELF note segments in a given buffer
967 *
968 * @ehdr_ptr: ELF header
969 * @notes_buf: buffer into which ELF note segments are copied
970 *
971 * This function is used to copy ELF note segment in the 1st kernel
972 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
973 * size of the buffer @notes_buf is equal to or larger than sum of the
974 * real ELF note segment headers and data.
975 *
976 * It is assumed that program headers with PT_NOTE type pointed to by
977 * @ehdr_ptr has already been updated by update_note_header_size_elf32
978 * and each of PT_NOTE program headers has actual ELF note segment
979 * size in its p_memsz member.
980 */
copy_notes_elf32(const Elf32_Ehdr * ehdr_ptr,char * notes_buf)981 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
982 {
983 int i, rc=0;
984 Elf32_Phdr *phdr_ptr;
985
986 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
987
988 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
989 u64 offset;
990 if (phdr_ptr->p_type != PT_NOTE)
991 continue;
992 offset = phdr_ptr->p_offset;
993 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
994 &offset);
995 if (rc < 0)
996 return rc;
997 notes_buf += phdr_ptr->p_memsz;
998 }
999
1000 return 0;
1001 }
1002
1003 /* Merges all the PT_NOTE headers into one. */
merge_note_headers_elf32(char * elfptr,size_t * elfsz,char ** notes_buf,size_t * notes_sz)1004 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
1005 char **notes_buf, size_t *notes_sz)
1006 {
1007 int i, nr_ptnote=0, rc=0;
1008 char *tmp;
1009 Elf32_Ehdr *ehdr_ptr;
1010 Elf32_Phdr phdr;
1011 u64 phdr_sz = 0, note_off;
1012
1013 ehdr_ptr = (Elf32_Ehdr *)elfptr;
1014
1015 rc = update_note_header_size_elf32(ehdr_ptr);
1016 if (rc < 0)
1017 return rc;
1018
1019 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
1020 if (rc < 0)
1021 return rc;
1022
1023 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
1024 *notes_buf = vmcore_alloc_buf(*notes_sz);
1025 if (!*notes_buf)
1026 return -ENOMEM;
1027
1028 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
1029 if (rc < 0)
1030 return rc;
1031
1032 /* Prepare merged PT_NOTE program header. */
1033 phdr.p_type = PT_NOTE;
1034 phdr.p_flags = 0;
1035 note_off = sizeof(Elf32_Ehdr) +
1036 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
1037 phdr.p_offset = roundup(note_off, PAGE_SIZE);
1038 phdr.p_vaddr = phdr.p_paddr = 0;
1039 phdr.p_filesz = phdr.p_memsz = phdr_sz;
1040 phdr.p_align = 0;
1041
1042 /* Add merged PT_NOTE program header*/
1043 tmp = elfptr + sizeof(Elf32_Ehdr);
1044 memcpy(tmp, &phdr, sizeof(phdr));
1045 tmp += sizeof(phdr);
1046
1047 /* Remove unwanted PT_NOTE program headers. */
1048 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
1049 *elfsz = *elfsz - i;
1050 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
1051 memset(elfptr + *elfsz, 0, i);
1052 *elfsz = roundup(*elfsz, PAGE_SIZE);
1053
1054 /* Modify e_phnum to reflect merged headers. */
1055 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
1056
1057 /* Store the size of all notes. We need this to update the note
1058 * header when the device dumps will be added.
1059 */
1060 elfnotes_orig_sz = phdr.p_memsz;
1061
1062 return 0;
1063 }
1064
1065 /* Add memory chunks represented by program headers to vmcore list. Also update
1066 * the new offset fields of exported program headers. */
process_ptload_program_headers_elf64(char * elfptr,size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1067 static int __init process_ptload_program_headers_elf64(char *elfptr,
1068 size_t elfsz,
1069 size_t elfnotes_sz,
1070 struct list_head *vc_list)
1071 {
1072 int i;
1073 Elf64_Ehdr *ehdr_ptr;
1074 Elf64_Phdr *phdr_ptr;
1075 loff_t vmcore_off;
1076 struct vmcore *new;
1077
1078 ehdr_ptr = (Elf64_Ehdr *)elfptr;
1079 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
1080
1081 /* Skip Elf header, program headers and Elf note segment. */
1082 vmcore_off = elfsz + elfnotes_sz;
1083
1084 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1085 u64 paddr, start, end, size;
1086
1087 if (phdr_ptr->p_type != PT_LOAD)
1088 continue;
1089
1090 paddr = phdr_ptr->p_offset;
1091 start = rounddown(paddr, PAGE_SIZE);
1092 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1093 size = end - start;
1094
1095 /* Add this contiguous chunk of memory to vmcore list.*/
1096 new = get_new_element();
1097 if (!new)
1098 return -ENOMEM;
1099 new->paddr = start;
1100 new->size = size;
1101 list_add_tail(&new->list, vc_list);
1102
1103 /* Update the program header offset. */
1104 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1105 vmcore_off = vmcore_off + size;
1106 }
1107 return 0;
1108 }
1109
process_ptload_program_headers_elf32(char * elfptr,size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1110 static int __init process_ptload_program_headers_elf32(char *elfptr,
1111 size_t elfsz,
1112 size_t elfnotes_sz,
1113 struct list_head *vc_list)
1114 {
1115 int i;
1116 Elf32_Ehdr *ehdr_ptr;
1117 Elf32_Phdr *phdr_ptr;
1118 loff_t vmcore_off;
1119 struct vmcore *new;
1120
1121 ehdr_ptr = (Elf32_Ehdr *)elfptr;
1122 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
1123
1124 /* Skip Elf header, program headers and Elf note segment. */
1125 vmcore_off = elfsz + elfnotes_sz;
1126
1127 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1128 u64 paddr, start, end, size;
1129
1130 if (phdr_ptr->p_type != PT_LOAD)
1131 continue;
1132
1133 paddr = phdr_ptr->p_offset;
1134 start = rounddown(paddr, PAGE_SIZE);
1135 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1136 size = end - start;
1137
1138 /* Add this contiguous chunk of memory to vmcore list.*/
1139 new = get_new_element();
1140 if (!new)
1141 return -ENOMEM;
1142 new->paddr = start;
1143 new->size = size;
1144 list_add_tail(&new->list, vc_list);
1145
1146 /* Update the program header offset */
1147 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1148 vmcore_off = vmcore_off + size;
1149 }
1150 return 0;
1151 }
1152
1153 /* Sets offset fields of vmcore elements. */
set_vmcore_list_offsets(size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1154 static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
1155 struct list_head *vc_list)
1156 {
1157 loff_t vmcore_off;
1158 struct vmcore *m;
1159
1160 /* Skip Elf header, program headers and Elf note segment. */
1161 vmcore_off = elfsz + elfnotes_sz;
1162
1163 list_for_each_entry(m, vc_list, list) {
1164 m->offset = vmcore_off;
1165 vmcore_off += m->size;
1166 }
1167 }
1168
free_elfcorebuf(void)1169 static void free_elfcorebuf(void)
1170 {
1171 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1172 elfcorebuf = NULL;
1173 vfree(elfnotes_buf);
1174 elfnotes_buf = NULL;
1175 }
1176
parse_crash_elf64_headers(void)1177 static int __init parse_crash_elf64_headers(void)
1178 {
1179 int rc=0;
1180 Elf64_Ehdr ehdr;
1181 u64 addr;
1182
1183 addr = elfcorehdr_addr;
1184
1185 /* Read Elf header */
1186 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1187 if (rc < 0)
1188 return rc;
1189
1190 /* Do some basic Verification. */
1191 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1192 (ehdr.e_type != ET_CORE) ||
1193 !vmcore_elf64_check_arch(&ehdr) ||
1194 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1195 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1196 ehdr.e_version != EV_CURRENT ||
1197 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1198 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1199 ehdr.e_phnum == 0) {
1200 pr_warn("Warning: Core image elf header is not sane\n");
1201 return -EINVAL;
1202 }
1203
1204 /* Read in all elf headers. */
1205 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1206 ehdr.e_phnum * sizeof(Elf64_Phdr);
1207 elfcorebuf_sz = elfcorebuf_sz_orig;
1208 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1209 get_order(elfcorebuf_sz_orig));
1210 if (!elfcorebuf)
1211 return -ENOMEM;
1212 addr = elfcorehdr_addr;
1213 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1214 if (rc < 0)
1215 goto fail;
1216
1217 /* Merge all PT_NOTE headers into one. */
1218 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1219 &elfnotes_buf, &elfnotes_sz);
1220 if (rc)
1221 goto fail;
1222 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1223 elfnotes_sz, &vmcore_list);
1224 if (rc)
1225 goto fail;
1226 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1227 return 0;
1228 fail:
1229 free_elfcorebuf();
1230 return rc;
1231 }
1232
parse_crash_elf32_headers(void)1233 static int __init parse_crash_elf32_headers(void)
1234 {
1235 int rc=0;
1236 Elf32_Ehdr ehdr;
1237 u64 addr;
1238
1239 addr = elfcorehdr_addr;
1240
1241 /* Read Elf header */
1242 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1243 if (rc < 0)
1244 return rc;
1245
1246 /* Do some basic Verification. */
1247 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1248 (ehdr.e_type != ET_CORE) ||
1249 !vmcore_elf32_check_arch(&ehdr) ||
1250 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1251 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1252 ehdr.e_version != EV_CURRENT ||
1253 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1254 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1255 ehdr.e_phnum == 0) {
1256 pr_warn("Warning: Core image elf header is not sane\n");
1257 return -EINVAL;
1258 }
1259
1260 /* Read in all elf headers. */
1261 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1262 elfcorebuf_sz = elfcorebuf_sz_orig;
1263 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1264 get_order(elfcorebuf_sz_orig));
1265 if (!elfcorebuf)
1266 return -ENOMEM;
1267 addr = elfcorehdr_addr;
1268 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1269 if (rc < 0)
1270 goto fail;
1271
1272 /* Merge all PT_NOTE headers into one. */
1273 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1274 &elfnotes_buf, &elfnotes_sz);
1275 if (rc)
1276 goto fail;
1277 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1278 elfnotes_sz, &vmcore_list);
1279 if (rc)
1280 goto fail;
1281 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1282 return 0;
1283 fail:
1284 free_elfcorebuf();
1285 return rc;
1286 }
1287
parse_crash_elf_headers(void)1288 static int __init parse_crash_elf_headers(void)
1289 {
1290 unsigned char e_ident[EI_NIDENT];
1291 u64 addr;
1292 int rc=0;
1293
1294 addr = elfcorehdr_addr;
1295 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1296 if (rc < 0)
1297 return rc;
1298 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1299 pr_warn("Warning: Core image elf header not found\n");
1300 return -EINVAL;
1301 }
1302
1303 if (e_ident[EI_CLASS] == ELFCLASS64) {
1304 rc = parse_crash_elf64_headers();
1305 if (rc)
1306 return rc;
1307 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1308 rc = parse_crash_elf32_headers();
1309 if (rc)
1310 return rc;
1311 } else {
1312 pr_warn("Warning: Core image elf header is not sane\n");
1313 return -EINVAL;
1314 }
1315
1316 /* Determine vmcore size. */
1317 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1318 &vmcore_list);
1319
1320 return 0;
1321 }
1322
1323 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1324 /**
1325 * vmcoredd_write_header - Write vmcore device dump header at the
1326 * beginning of the dump's buffer.
1327 * @buf: Output buffer where the note is written
1328 * @data: Dump info
1329 * @size: Size of the dump
1330 *
1331 * Fills beginning of the dump's buffer with vmcore device dump header.
1332 */
vmcoredd_write_header(void * buf,struct vmcoredd_data * data,u32 size)1333 static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
1334 u32 size)
1335 {
1336 struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
1337
1338 vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
1339 vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
1340 vdd_hdr->n_type = NT_VMCOREDD;
1341
1342 strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME,
1343 sizeof(vdd_hdr->name));
1344 memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name));
1345 }
1346
1347 /**
1348 * vmcoredd_update_program_headers - Update all Elf program headers
1349 * @elfptr: Pointer to elf header
1350 * @elfnotesz: Size of elf notes aligned to page size
1351 * @vmcoreddsz: Size of device dumps to be added to elf note header
1352 *
1353 * Determine type of Elf header (Elf64 or Elf32) and update the elf note size.
1354 * Also update the offsets of all the program headers after the elf note header.
1355 */
vmcoredd_update_program_headers(char * elfptr,size_t elfnotesz,size_t vmcoreddsz)1356 static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
1357 size_t vmcoreddsz)
1358 {
1359 unsigned char *e_ident = (unsigned char *)elfptr;
1360 u64 start, end, size;
1361 loff_t vmcore_off;
1362 u32 i;
1363
1364 vmcore_off = elfcorebuf_sz + elfnotesz;
1365
1366 if (e_ident[EI_CLASS] == ELFCLASS64) {
1367 Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
1368 Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
1369
1370 /* Update all program headers */
1371 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1372 if (phdr->p_type == PT_NOTE) {
1373 /* Update note size */
1374 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1375 phdr->p_filesz = phdr->p_memsz;
1376 continue;
1377 }
1378
1379 start = rounddown(phdr->p_offset, PAGE_SIZE);
1380 end = roundup(phdr->p_offset + phdr->p_memsz,
1381 PAGE_SIZE);
1382 size = end - start;
1383 phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1384 vmcore_off += size;
1385 }
1386 } else {
1387 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
1388 Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
1389
1390 /* Update all program headers */
1391 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1392 if (phdr->p_type == PT_NOTE) {
1393 /* Update note size */
1394 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1395 phdr->p_filesz = phdr->p_memsz;
1396 continue;
1397 }
1398
1399 start = rounddown(phdr->p_offset, PAGE_SIZE);
1400 end = roundup(phdr->p_offset + phdr->p_memsz,
1401 PAGE_SIZE);
1402 size = end - start;
1403 phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1404 vmcore_off += size;
1405 }
1406 }
1407 }
1408
1409 /**
1410 * vmcoredd_update_size - Update the total size of the device dumps and update
1411 * Elf header
1412 * @dump_size: Size of the current device dump to be added to total size
1413 *
1414 * Update the total size of all the device dumps and update the Elf program
1415 * headers. Calculate the new offsets for the vmcore list and update the
1416 * total vmcore size.
1417 */
vmcoredd_update_size(size_t dump_size)1418 static void vmcoredd_update_size(size_t dump_size)
1419 {
1420 vmcoredd_orig_sz += dump_size;
1421 elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
1422 vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
1423 vmcoredd_orig_sz);
1424
1425 /* Update vmcore list offsets */
1426 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1427
1428 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1429 &vmcore_list);
1430 proc_vmcore->size = vmcore_size;
1431 }
1432
1433 /**
1434 * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
1435 * @data: dump info.
1436 *
1437 * Allocate a buffer and invoke the calling driver's dump collect routine.
1438 * Write Elf note at the beginning of the buffer to indicate vmcore device
1439 * dump and add the dump to global list.
1440 */
vmcore_add_device_dump(struct vmcoredd_data * data)1441 int vmcore_add_device_dump(struct vmcoredd_data *data)
1442 {
1443 struct vmcoredd_node *dump;
1444 void *buf = NULL;
1445 size_t data_size;
1446 int ret;
1447
1448 if (!data || !strlen(data->dump_name) ||
1449 !data->vmcoredd_callback || !data->size)
1450 return -EINVAL;
1451
1452 dump = vzalloc(sizeof(*dump));
1453 if (!dump) {
1454 ret = -ENOMEM;
1455 goto out_err;
1456 }
1457
1458 /* Keep size of the buffer page aligned so that it can be mmaped */
1459 data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
1460 PAGE_SIZE);
1461
1462 /* Allocate buffer for driver's to write their dumps */
1463 buf = vmcore_alloc_buf(data_size);
1464 if (!buf) {
1465 ret = -ENOMEM;
1466 goto out_err;
1467 }
1468
1469 vmcoredd_write_header(buf, data, data_size -
1470 sizeof(struct vmcoredd_header));
1471
1472 /* Invoke the driver's dump collection routing */
1473 ret = data->vmcoredd_callback(data, buf +
1474 sizeof(struct vmcoredd_header));
1475 if (ret)
1476 goto out_err;
1477
1478 dump->buf = buf;
1479 dump->size = data_size;
1480
1481 /* Add the dump to driver sysfs list */
1482 mutex_lock(&vmcoredd_mutex);
1483 list_add_tail(&dump->list, &vmcoredd_list);
1484 mutex_unlock(&vmcoredd_mutex);
1485
1486 vmcoredd_update_size(data_size);
1487 return 0;
1488
1489 out_err:
1490 if (buf)
1491 vfree(buf);
1492
1493 if (dump)
1494 vfree(dump);
1495
1496 return ret;
1497 }
1498 EXPORT_SYMBOL(vmcore_add_device_dump);
1499 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1500
1501 /* Free all dumps in vmcore device dump list */
vmcore_free_device_dumps(void)1502 static void vmcore_free_device_dumps(void)
1503 {
1504 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1505 mutex_lock(&vmcoredd_mutex);
1506 while (!list_empty(&vmcoredd_list)) {
1507 struct vmcoredd_node *dump;
1508
1509 dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
1510 list);
1511 list_del(&dump->list);
1512 vfree(dump->buf);
1513 vfree(dump);
1514 }
1515 mutex_unlock(&vmcoredd_mutex);
1516 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1517 }
1518
1519 /* Init function for vmcore module. */
vmcore_init(void)1520 static int __init vmcore_init(void)
1521 {
1522 int rc = 0;
1523
1524 /* Allow architectures to allocate ELF header in 2nd kernel */
1525 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1526 if (rc)
1527 return rc;
1528 /*
1529 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1530 * then capture the dump.
1531 */
1532 if (!(is_vmcore_usable()))
1533 return rc;
1534 rc = parse_crash_elf_headers();
1535 if (rc) {
1536 pr_warn("Kdump: vmcore not initialized\n");
1537 return rc;
1538 }
1539 elfcorehdr_free(elfcorehdr_addr);
1540 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1541
1542 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1543 if (proc_vmcore)
1544 proc_vmcore->size = vmcore_size;
1545 return 0;
1546 }
1547 fs_initcall(vmcore_init);
1548
1549 /* Cleanup function for vmcore module. */
vmcore_cleanup(void)1550 void vmcore_cleanup(void)
1551 {
1552 if (proc_vmcore) {
1553 proc_remove(proc_vmcore);
1554 proc_vmcore = NULL;
1555 }
1556
1557 /* clear the vmcore list. */
1558 while (!list_empty(&vmcore_list)) {
1559 struct vmcore *m;
1560
1561 m = list_first_entry(&vmcore_list, struct vmcore, list);
1562 list_del(&m->list);
1563 kfree(m);
1564 }
1565 free_elfcorebuf();
1566
1567 /* clear vmcore device dump list */
1568 vmcore_free_device_dumps();
1569 }
1570