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1/*
2 * fs/proc/kcore.c kernel ELF core dumper
3 *
4 * Modelled on fs/exec.c:aout_core_dump()
5 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
6 * ELF version written by David Howells <David.Howells@nexor.co.uk>
7 * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
8 * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
9 * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
10 */
11
12#include <linux/mm.h>
13#include <linux/proc_fs.h>
14#include <linux/user.h>
15#include <linux/capability.h>
16#include <linux/elf.h>
17#include <linux/elfcore.h>
18#include <linux/vmalloc.h>
19#include <linux/highmem.h>
20#include <linux/bootmem.h>
21#include <linux/init.h>
22#include <linux/slab.h>
23#include <asm/uaccess.h>
24#include <asm/io.h>
25#include <linux/list.h>
26#include <linux/ioport.h>
27#include <linux/memory.h>
28#include <asm/sections.h>
29
30#define CORE_STR "CORE"
31
32#ifndef ELF_CORE_EFLAGS
33#define ELF_CORE_EFLAGS 0
34#endif
35
36static struct proc_dir_entry *proc_root_kcore;
37
38
39#ifndef kc_vaddr_to_offset
40#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
41#endif
42#ifndef kc_offset_to_vaddr
43#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
44#endif
45
46/* An ELF note in memory */
47struct memelfnote
48{
49 const char *name;
50 int type;
51 unsigned int datasz;
52 void *data;
53};
54
55static LIST_HEAD(kclist_head);
56static DEFINE_RWLOCK(kclist_lock);
57static int kcore_need_update = 1;
58
59void
60kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
61{
62 new->addr = (unsigned long)addr;
63 new->size = size;
64 new->type = type;
65
66 write_lock(&kclist_lock);
67 list_add_tail(&new->list, &kclist_head);
68 write_unlock(&kclist_lock);
69}
70
71static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
72{
73 size_t try, size;
74 struct kcore_list *m;
75
76 *nphdr = 1; /* PT_NOTE */
77 size = 0;
78
79 list_for_each_entry(m, &kclist_head, list) {
80 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
81 if (try > size)
82 size = try;
83 *nphdr = *nphdr + 1;
84 }
85 *elf_buflen = sizeof(struct elfhdr) +
86 (*nphdr + 2)*sizeof(struct elf_phdr) +
87 3 * ((sizeof(struct elf_note)) +
88 roundup(sizeof(CORE_STR), 4)) +
89 roundup(sizeof(struct elf_prstatus), 4) +
90 roundup(sizeof(struct elf_prpsinfo), 4) +
91 roundup(sizeof(struct task_struct), 4);
92 *elf_buflen = PAGE_ALIGN(*elf_buflen);
93 return size + *elf_buflen;
94}
95
96static void free_kclist_ents(struct list_head *head)
97{
98 struct kcore_list *tmp, *pos;
99
100 list_for_each_entry_safe(pos, tmp, head, list) {
101 list_del(&pos->list);
102 kfree(pos);
103 }
104}
105/*
106 * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list.
107 */
108static void __kcore_update_ram(struct list_head *list)
109{
110 int nphdr;
111 size_t size;
112 struct kcore_list *tmp, *pos;
113 LIST_HEAD(garbage);
114
115 write_lock(&kclist_lock);
116 if (kcore_need_update) {
117 list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
118 if (pos->type == KCORE_RAM
119 || pos->type == KCORE_VMEMMAP)
120 list_move(&pos->list, &garbage);
121 }
122 list_splice_tail(list, &kclist_head);
123 } else
124 list_splice(list, &garbage);
125 kcore_need_update = 0;
126 proc_root_kcore->size = get_kcore_size(&nphdr, &size);
127 write_unlock(&kclist_lock);
128
129 free_kclist_ents(&garbage);
130}
131
132
133#ifdef CONFIG_HIGHMEM
134/*
135 * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
136 * because memory hole is not as big as !HIGHMEM case.
137 * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
138 */
139static int kcore_update_ram(void)
140{
141 LIST_HEAD(head);
142 struct kcore_list *ent;
143 int ret = 0;
144
145 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
146 if (!ent)
147 return -ENOMEM;
148 ent->addr = (unsigned long)__va(0);
149 ent->size = max_low_pfn << PAGE_SHIFT;
150 ent->type = KCORE_RAM;
151 list_add(&ent->list, &head);
152 __kcore_update_ram(&head);
153 return ret;
154}
155
156#else /* !CONFIG_HIGHMEM */
157
158#ifdef CONFIG_SPARSEMEM_VMEMMAP
159/* calculate vmemmap's address from given system ram pfn and register it */
160static int
161get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
162{
163 unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
164 unsigned long nr_pages = ent->size >> PAGE_SHIFT;
165 unsigned long start, end;
166 struct kcore_list *vmm, *tmp;
167
168
169 start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
170 end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
171 end = ALIGN(end, PAGE_SIZE);
172 /* overlap check (because we have to align page */
173 list_for_each_entry(tmp, head, list) {
174 if (tmp->type != KCORE_VMEMMAP)
175 continue;
176 if (start < tmp->addr + tmp->size)
177 if (end > tmp->addr)
178 end = tmp->addr;
179 }
180 if (start < end) {
181 vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
182 if (!vmm)
183 return 0;
184 vmm->addr = start;
185 vmm->size = end - start;
186 vmm->type = KCORE_VMEMMAP;
187 list_add_tail(&vmm->list, head);
188 }
189 return 1;
190
191}
192#else
193static int
194get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
195{
196 return 1;
197}
198
199#endif
200
201static int
202kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
203{
204 struct list_head *head = (struct list_head *)arg;
205 struct kcore_list *ent;
206
207 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
208 if (!ent)
209 return -ENOMEM;
210 ent->addr = (unsigned long)__va((pfn << PAGE_SHIFT));
211 ent->size = nr_pages << PAGE_SHIFT;
212
213 /* Sanity check: Can happen in 32bit arch...maybe */
214 if (ent->addr < (unsigned long) __va(0))
215 goto free_out;
216
217 /* cut not-mapped area. ....from ppc-32 code. */
218 if (ULONG_MAX - ent->addr < ent->size)
219 ent->size = ULONG_MAX - ent->addr;
220
221 /* cut when vmalloc() area is higher than direct-map area */
222 if (VMALLOC_START > (unsigned long)__va(0)) {
223 if (ent->addr > VMALLOC_START)
224 goto free_out;
225 if (VMALLOC_START - ent->addr < ent->size)
226 ent->size = VMALLOC_START - ent->addr;
227 }
228
229 ent->type = KCORE_RAM;
230 list_add_tail(&ent->list, head);
231
232 if (!get_sparsemem_vmemmap_info(ent, head)) {
233 list_del(&ent->list);
234 goto free_out;
235 }
236
237 return 0;
238free_out:
239 kfree(ent);
240 return 1;
241}
242
243static int kcore_update_ram(void)
244{
245 int nid, ret;
246 unsigned long end_pfn;
247 LIST_HEAD(head);
248
249 /* Not inialized....update now */
250 /* find out "max pfn" */
251 end_pfn = 0;
252 for_each_node_state(nid, N_HIGH_MEMORY) {
253 unsigned long node_end;
254 node_end = NODE_DATA(nid)->node_start_pfn +
255 NODE_DATA(nid)->node_spanned_pages;
256 if (end_pfn < node_end)
257 end_pfn = node_end;
258 }
259 /* scan 0 to max_pfn */
260 ret = walk_system_ram_range(0, end_pfn, &head, kclist_add_private);
261 if (ret) {
262 free_kclist_ents(&head);
263 return -ENOMEM;
264 }
265 __kcore_update_ram(&head);
266 return ret;
267}
268#endif /* CONFIG_HIGHMEM */
269
270/*****************************************************************************/
271/*
272 * determine size of ELF note
273 */
274static int notesize(struct memelfnote *en)
275{
276 int sz;
277
278 sz = sizeof(struct elf_note);
279 sz += roundup((strlen(en->name) + 1), 4);
280 sz += roundup(en->datasz, 4);
281
282 return sz;
283} /* end notesize() */
284
285/*****************************************************************************/
286/*
287 * store a note in the header buffer
288 */
289static char *storenote(struct memelfnote *men, char *bufp)
290{
291 struct elf_note en;
292
293#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
294
295 en.n_namesz = strlen(men->name) + 1;
296 en.n_descsz = men->datasz;
297 en.n_type = men->type;
298
299 DUMP_WRITE(&en, sizeof(en));
300 DUMP_WRITE(men->name, en.n_namesz);
301
302 /* XXX - cast from long long to long to avoid need for libgcc.a */
303 bufp = (char*) roundup((unsigned long)bufp,4);
304 DUMP_WRITE(men->data, men->datasz);
305 bufp = (char*) roundup((unsigned long)bufp,4);
306
307#undef DUMP_WRITE
308
309 return bufp;
310} /* end storenote() */
311
312/*
313 * store an ELF coredump header in the supplied buffer
314 * nphdr is the number of elf_phdr to insert
315 */
316static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
317{
318 struct elf_prstatus prstatus; /* NT_PRSTATUS */
319 struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
320 struct elf_phdr *nhdr, *phdr;
321 struct elfhdr *elf;
322 struct memelfnote notes[3];
323 off_t offset = 0;
324 struct kcore_list *m;
325
326 /* setup ELF header */
327 elf = (struct elfhdr *) bufp;
328 bufp += sizeof(struct elfhdr);
329 offset += sizeof(struct elfhdr);
330 memcpy(elf->e_ident, ELFMAG, SELFMAG);
331 elf->e_ident[EI_CLASS] = ELF_CLASS;
332 elf->e_ident[EI_DATA] = ELF_DATA;
333 elf->e_ident[EI_VERSION]= EV_CURRENT;
334 elf->e_ident[EI_OSABI] = ELF_OSABI;
335 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
336 elf->e_type = ET_CORE;
337 elf->e_machine = ELF_ARCH;
338 elf->e_version = EV_CURRENT;
339 elf->e_entry = 0;
340 elf->e_phoff = sizeof(struct elfhdr);
341 elf->e_shoff = 0;
342 elf->e_flags = ELF_CORE_EFLAGS;
343 elf->e_ehsize = sizeof(struct elfhdr);
344 elf->e_phentsize= sizeof(struct elf_phdr);
345 elf->e_phnum = nphdr;
346 elf->e_shentsize= 0;
347 elf->e_shnum = 0;
348 elf->e_shstrndx = 0;
349
350 /* setup ELF PT_NOTE program header */
351 nhdr = (struct elf_phdr *) bufp;
352 bufp += sizeof(struct elf_phdr);
353 offset += sizeof(struct elf_phdr);
354 nhdr->p_type = PT_NOTE;
355 nhdr->p_offset = 0;
356 nhdr->p_vaddr = 0;
357 nhdr->p_paddr = 0;
358 nhdr->p_filesz = 0;
359 nhdr->p_memsz = 0;
360 nhdr->p_flags = 0;
361 nhdr->p_align = 0;
362
363 /* setup ELF PT_LOAD program header for every area */
364 list_for_each_entry(m, &kclist_head, list) {
365 phdr = (struct elf_phdr *) bufp;
366 bufp += sizeof(struct elf_phdr);
367 offset += sizeof(struct elf_phdr);
368
369 phdr->p_type = PT_LOAD;
370 phdr->p_flags = PF_R|PF_W|PF_X;
371 phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
372 phdr->p_vaddr = (size_t)m->addr;
373 phdr->p_paddr = 0;
374 phdr->p_filesz = phdr->p_memsz = m->size;
375 phdr->p_align = PAGE_SIZE;
376 }
377
378 /*
379 * Set up the notes in similar form to SVR4 core dumps made
380 * with info from their /proc.
381 */
382 nhdr->p_offset = offset;
383
384 /* set up the process status */
385 notes[0].name = CORE_STR;
386 notes[0].type = NT_PRSTATUS;
387 notes[0].datasz = sizeof(struct elf_prstatus);
388 notes[0].data = &prstatus;
389
390 memset(&prstatus, 0, sizeof(struct elf_prstatus));
391
392 nhdr->p_filesz = notesize(¬es[0]);
393 bufp = storenote(¬es[0], bufp);
394
395 /* set up the process info */
396 notes[1].name = CORE_STR;
397 notes[1].type = NT_PRPSINFO;
398 notes[1].datasz = sizeof(struct elf_prpsinfo);
399 notes[1].data = &prpsinfo;
400
401 memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
402 prpsinfo.pr_state = 0;
403 prpsinfo.pr_sname = 'R';
404 prpsinfo.pr_zomb = 0;
405
406 strcpy(prpsinfo.pr_fname, "vmlinux");
407 strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
408
409 nhdr->p_filesz += notesize(¬es[1]);
410 bufp = storenote(¬es[1], bufp);
411
412 /* set up the task structure */
413 notes[2].name = CORE_STR;
414 notes[2].type = NT_TASKSTRUCT;
415 notes[2].datasz = sizeof(struct task_struct);
416 notes[2].data = current;
417
418 nhdr->p_filesz += notesize(¬es[2]);
419 bufp = storenote(¬es[2], bufp);
420
421} /* end elf_kcore_store_hdr() */
422
423/*****************************************************************************/
424/*
425 * read from the ELF header and then kernel memory
426 */
427static ssize_t
428read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
429{
430 ssize_t acc = 0;
431 size_t size, tsz;
432 size_t elf_buflen;
433 int nphdr;
434 unsigned long start;
435
436 read_lock(&kclist_lock);
437 size = get_kcore_size(&nphdr, &elf_buflen);
438
439 if (buflen == 0 || *fpos >= size) {
440 read_unlock(&kclist_lock);
441 return 0;
442 }
443
444 /* trim buflen to not go beyond EOF */
445 if (buflen > size - *fpos)
446 buflen = size - *fpos;
447
448 /* construct an ELF core header if we'll need some of it */
449 if (*fpos < elf_buflen) {
450 char * elf_buf;
451
452 tsz = elf_buflen - *fpos;
453 if (buflen < tsz)
454 tsz = buflen;
455 elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
456 if (!elf_buf) {
457 read_unlock(&kclist_lock);
458 return -ENOMEM;
459 }
460 elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
461 read_unlock(&kclist_lock);
462 if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
463 kfree(elf_buf);
464 return -EFAULT;
465 }
466 kfree(elf_buf);
467 buflen -= tsz;
468 *fpos += tsz;
469 buffer += tsz;
470 acc += tsz;
471
472 /* leave now if filled buffer already */
473 if (buflen == 0)
474 return acc;
475 } else
476 read_unlock(&kclist_lock);
477
478 /*
479 * Check to see if our file offset matches with any of
480 * the addresses in the elf_phdr on our list.
481 */
482 start = kc_offset_to_vaddr(*fpos - elf_buflen);
483 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
484 tsz = buflen;
485
486 while (buflen) {
487 struct kcore_list *m;
488
489 read_lock(&kclist_lock);
490 list_for_each_entry(m, &kclist_head, list) {
491 if (start >= m->addr && start < (m->addr+m->size))
492 break;
493 }
494 read_unlock(&kclist_lock);
495
496 if (&m->list == &kclist_head) {
497 if (clear_user(buffer, tsz))
498 return -EFAULT;
499 } else if (is_vmalloc_or_module_addr((void *)start)) {
500 char * elf_buf;
501
502 elf_buf = kzalloc(tsz, GFP_KERNEL);
503 if (!elf_buf)
504 return -ENOMEM;
505 vread(elf_buf, (char *)start, tsz);
506 /* we have to zero-fill user buffer even if no read */
507 if (copy_to_user(buffer, elf_buf, tsz)) {
508 kfree(elf_buf);
509 return -EFAULT;
510 }
511 kfree(elf_buf);
512 } else {
513 if (kern_addr_valid(start)) {
514 unsigned long n;
515
516 n = copy_to_user(buffer, (char *)start, tsz);
517 /*
518 * We cannot distinguish between fault on source
519 * and fault on destination. When this happens
520 * we clear too and hope it will trigger the
521 * EFAULT again.
522 */
523 if (n) {
524 if (clear_user(buffer + tsz - n,
525 n))
526 return -EFAULT;
527 }
528 } else {
529 if (clear_user(buffer, tsz))
530 return -EFAULT;
531 }
532 }
533 buflen -= tsz;
534 *fpos += tsz;
535 buffer += tsz;
536 acc += tsz;
537 start += tsz;
538 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
539 }
540
541 return acc;
542}
543
544
545static int open_kcore(struct inode *inode, struct file *filp)
546{
547 if (!capable(CAP_SYS_RAWIO))
548 return -EPERM;
549 if (kcore_need_update)
550 kcore_update_ram();
551 if (i_size_read(inode) != proc_root_kcore->size) {
552 mutex_lock(&inode->i_mutex);
553 i_size_write(inode, proc_root_kcore->size);
554 mutex_unlock(&inode->i_mutex);
555 }
556 return 0;
557}
558
559
560static const struct file_operations proc_kcore_operations = {
561 .read = read_kcore,
562 .open = open_kcore,
563 .llseek = default_llseek,
564};
565
566#ifdef CONFIG_MEMORY_HOTPLUG
567/* just remember that we have to update kcore */
568static int __meminit kcore_callback(struct notifier_block *self,
569 unsigned long action, void *arg)
570{
571 switch (action) {
572 case MEM_ONLINE:
573 case MEM_OFFLINE:
574 write_lock(&kclist_lock);
575 kcore_need_update = 1;
576 write_unlock(&kclist_lock);
577 }
578 return NOTIFY_OK;
579}
580#endif
581
582
583static struct kcore_list kcore_vmalloc;
584
585#ifdef CONFIG_ARCH_PROC_KCORE_TEXT
586static struct kcore_list kcore_text;
587/*
588 * If defined, special segment is used for mapping kernel text instead of
589 * direct-map area. We need to create special TEXT section.
590 */
591static void __init proc_kcore_text_init(void)
592{
593 kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
594}
595#else
596static void __init proc_kcore_text_init(void)
597{
598}
599#endif
600
601#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
602/*
603 * MODULES_VADDR has no intersection with VMALLOC_ADDR.
604 */
605struct kcore_list kcore_modules;
606static void __init add_modules_range(void)
607{
608 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
609 MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
610}
611#else
612static void __init add_modules_range(void)
613{
614}
615#endif
616
617static int __init proc_kcore_init(void)
618{
619 proc_root_kcore = proc_create("kcore", S_IRUSR, NULL,
620 &proc_kcore_operations);
621 if (!proc_root_kcore) {
622 printk(KERN_ERR "couldn't create /proc/kcore\n");
623 return 0; /* Always returns 0. */
624 }
625 /* Store text area if it's special */
626 proc_kcore_text_init();
627 /* Store vmalloc area */
628 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
629 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
630 add_modules_range();
631 /* Store direct-map area from physical memory map */
632 kcore_update_ram();
633 hotplug_memory_notifier(kcore_callback, 0);
634
635 return 0;
636}
637module_init(proc_kcore_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/proc/kcore.c kernel ELF core dumper
4 *
5 * Modelled on fs/exec.c:aout_core_dump()
6 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
7 * ELF version written by David Howells <David.Howells@nexor.co.uk>
8 * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
9 * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
10 * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
11 */
12
13#include <linux/crash_core.h>
14#include <linux/mm.h>
15#include <linux/proc_fs.h>
16#include <linux/kcore.h>
17#include <linux/user.h>
18#include <linux/capability.h>
19#include <linux/elf.h>
20#include <linux/elfcore.h>
21#include <linux/notifier.h>
22#include <linux/vmalloc.h>
23#include <linux/highmem.h>
24#include <linux/printk.h>
25#include <linux/memblock.h>
26#include <linux/init.h>
27#include <linux/slab.h>
28#include <linux/uaccess.h>
29#include <asm/io.h>
30#include <linux/list.h>
31#include <linux/ioport.h>
32#include <linux/memory.h>
33#include <linux/sched/task.h>
34#include <linux/security.h>
35#include <asm/sections.h>
36#include "internal.h"
37
38#define CORE_STR "CORE"
39
40#ifndef ELF_CORE_EFLAGS
41#define ELF_CORE_EFLAGS 0
42#endif
43
44static struct proc_dir_entry *proc_root_kcore;
45
46
47#ifndef kc_vaddr_to_offset
48#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
49#endif
50#ifndef kc_offset_to_vaddr
51#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
52#endif
53
54static LIST_HEAD(kclist_head);
55static DECLARE_RWSEM(kclist_lock);
56static int kcore_need_update = 1;
57
58/*
59 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
60 * Same as oldmem_pfn_is_ram in vmcore
61 */
62static int (*mem_pfn_is_ram)(unsigned long pfn);
63
64int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn))
65{
66 if (mem_pfn_is_ram)
67 return -EBUSY;
68 mem_pfn_is_ram = fn;
69 return 0;
70}
71
72static int pfn_is_ram(unsigned long pfn)
73{
74 if (mem_pfn_is_ram)
75 return mem_pfn_is_ram(pfn);
76 else
77 return 1;
78}
79
80/* This doesn't grab kclist_lock, so it should only be used at init time. */
81void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
82 int type)
83{
84 new->addr = (unsigned long)addr;
85 new->size = size;
86 new->type = type;
87
88 list_add_tail(&new->list, &kclist_head);
89}
90
91static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,
92 size_t *data_offset)
93{
94 size_t try, size;
95 struct kcore_list *m;
96
97 *nphdr = 1; /* PT_NOTE */
98 size = 0;
99
100 list_for_each_entry(m, &kclist_head, list) {
101 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
102 if (try > size)
103 size = try;
104 *nphdr = *nphdr + 1;
105 }
106
107 *phdrs_len = *nphdr * sizeof(struct elf_phdr);
108 *notes_len = (4 * sizeof(struct elf_note) +
109 3 * ALIGN(sizeof(CORE_STR), 4) +
110 VMCOREINFO_NOTE_NAME_BYTES +
111 ALIGN(sizeof(struct elf_prstatus), 4) +
112 ALIGN(sizeof(struct elf_prpsinfo), 4) +
113 ALIGN(arch_task_struct_size, 4) +
114 ALIGN(vmcoreinfo_size, 4));
115 *data_offset = PAGE_ALIGN(sizeof(struct elfhdr) + *phdrs_len +
116 *notes_len);
117 return *data_offset + size;
118}
119
120#ifdef CONFIG_HIGHMEM
121/*
122 * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
123 * because memory hole is not as big as !HIGHMEM case.
124 * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
125 */
126static int kcore_ram_list(struct list_head *head)
127{
128 struct kcore_list *ent;
129
130 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
131 if (!ent)
132 return -ENOMEM;
133 ent->addr = (unsigned long)__va(0);
134 ent->size = max_low_pfn << PAGE_SHIFT;
135 ent->type = KCORE_RAM;
136 list_add(&ent->list, head);
137 return 0;
138}
139
140#else /* !CONFIG_HIGHMEM */
141
142#ifdef CONFIG_SPARSEMEM_VMEMMAP
143/* calculate vmemmap's address from given system ram pfn and register it */
144static int
145get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
146{
147 unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
148 unsigned long nr_pages = ent->size >> PAGE_SHIFT;
149 unsigned long start, end;
150 struct kcore_list *vmm, *tmp;
151
152
153 start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
154 end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
155 end = PAGE_ALIGN(end);
156 /* overlap check (because we have to align page */
157 list_for_each_entry(tmp, head, list) {
158 if (tmp->type != KCORE_VMEMMAP)
159 continue;
160 if (start < tmp->addr + tmp->size)
161 if (end > tmp->addr)
162 end = tmp->addr;
163 }
164 if (start < end) {
165 vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
166 if (!vmm)
167 return 0;
168 vmm->addr = start;
169 vmm->size = end - start;
170 vmm->type = KCORE_VMEMMAP;
171 list_add_tail(&vmm->list, head);
172 }
173 return 1;
174
175}
176#else
177static int
178get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
179{
180 return 1;
181}
182
183#endif
184
185static int
186kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
187{
188 struct list_head *head = (struct list_head *)arg;
189 struct kcore_list *ent;
190 struct page *p;
191
192 if (!pfn_valid(pfn))
193 return 1;
194
195 p = pfn_to_page(pfn);
196 if (!memmap_valid_within(pfn, p, page_zone(p)))
197 return 1;
198
199 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
200 if (!ent)
201 return -ENOMEM;
202 ent->addr = (unsigned long)page_to_virt(p);
203 ent->size = nr_pages << PAGE_SHIFT;
204
205 if (!virt_addr_valid(ent->addr))
206 goto free_out;
207
208 /* cut not-mapped area. ....from ppc-32 code. */
209 if (ULONG_MAX - ent->addr < ent->size)
210 ent->size = ULONG_MAX - ent->addr;
211
212 /*
213 * We've already checked virt_addr_valid so we know this address
214 * is a valid pointer, therefore we can check against it to determine
215 * if we need to trim
216 */
217 if (VMALLOC_START > ent->addr) {
218 if (VMALLOC_START - ent->addr < ent->size)
219 ent->size = VMALLOC_START - ent->addr;
220 }
221
222 ent->type = KCORE_RAM;
223 list_add_tail(&ent->list, head);
224
225 if (!get_sparsemem_vmemmap_info(ent, head)) {
226 list_del(&ent->list);
227 goto free_out;
228 }
229
230 return 0;
231free_out:
232 kfree(ent);
233 return 1;
234}
235
236static int kcore_ram_list(struct list_head *list)
237{
238 int nid, ret;
239 unsigned long end_pfn;
240
241 /* Not inialized....update now */
242 /* find out "max pfn" */
243 end_pfn = 0;
244 for_each_node_state(nid, N_MEMORY) {
245 unsigned long node_end;
246 node_end = node_end_pfn(nid);
247 if (end_pfn < node_end)
248 end_pfn = node_end;
249 }
250 /* scan 0 to max_pfn */
251 ret = walk_system_ram_range(0, end_pfn, list, kclist_add_private);
252 if (ret)
253 return -ENOMEM;
254 return 0;
255}
256#endif /* CONFIG_HIGHMEM */
257
258static int kcore_update_ram(void)
259{
260 LIST_HEAD(list);
261 LIST_HEAD(garbage);
262 int nphdr;
263 size_t phdrs_len, notes_len, data_offset;
264 struct kcore_list *tmp, *pos;
265 int ret = 0;
266
267 down_write(&kclist_lock);
268 if (!xchg(&kcore_need_update, 0))
269 goto out;
270
271 ret = kcore_ram_list(&list);
272 if (ret) {
273 /* Couldn't get the RAM list, try again next time. */
274 WRITE_ONCE(kcore_need_update, 1);
275 list_splice_tail(&list, &garbage);
276 goto out;
277 }
278
279 list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
280 if (pos->type == KCORE_RAM || pos->type == KCORE_VMEMMAP)
281 list_move(&pos->list, &garbage);
282 }
283 list_splice_tail(&list, &kclist_head);
284
285 proc_root_kcore->size = get_kcore_size(&nphdr, &phdrs_len, ¬es_len,
286 &data_offset);
287
288out:
289 up_write(&kclist_lock);
290 list_for_each_entry_safe(pos, tmp, &garbage, list) {
291 list_del(&pos->list);
292 kfree(pos);
293 }
294 return ret;
295}
296
297static void append_kcore_note(char *notes, size_t *i, const char *name,
298 unsigned int type, const void *desc,
299 size_t descsz)
300{
301 struct elf_note *note = (struct elf_note *)¬es[*i];
302
303 note->n_namesz = strlen(name) + 1;
304 note->n_descsz = descsz;
305 note->n_type = type;
306 *i += sizeof(*note);
307 memcpy(¬es[*i], name, note->n_namesz);
308 *i = ALIGN(*i + note->n_namesz, 4);
309 memcpy(¬es[*i], desc, descsz);
310 *i = ALIGN(*i + descsz, 4);
311}
312
313static ssize_t
314read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
315{
316 char *buf = file->private_data;
317 size_t phdrs_offset, notes_offset, data_offset;
318 size_t phdrs_len, notes_len;
319 struct kcore_list *m;
320 size_t tsz;
321 int nphdr;
322 unsigned long start;
323 size_t orig_buflen = buflen;
324 int ret = 0;
325
326 down_read(&kclist_lock);
327
328 get_kcore_size(&nphdr, &phdrs_len, ¬es_len, &data_offset);
329 phdrs_offset = sizeof(struct elfhdr);
330 notes_offset = phdrs_offset + phdrs_len;
331
332 /* ELF file header. */
333 if (buflen && *fpos < sizeof(struct elfhdr)) {
334 struct elfhdr ehdr = {
335 .e_ident = {
336 [EI_MAG0] = ELFMAG0,
337 [EI_MAG1] = ELFMAG1,
338 [EI_MAG2] = ELFMAG2,
339 [EI_MAG3] = ELFMAG3,
340 [EI_CLASS] = ELF_CLASS,
341 [EI_DATA] = ELF_DATA,
342 [EI_VERSION] = EV_CURRENT,
343 [EI_OSABI] = ELF_OSABI,
344 },
345 .e_type = ET_CORE,
346 .e_machine = ELF_ARCH,
347 .e_version = EV_CURRENT,
348 .e_phoff = sizeof(struct elfhdr),
349 .e_flags = ELF_CORE_EFLAGS,
350 .e_ehsize = sizeof(struct elfhdr),
351 .e_phentsize = sizeof(struct elf_phdr),
352 .e_phnum = nphdr,
353 };
354
355 tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);
356 if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) {
357 ret = -EFAULT;
358 goto out;
359 }
360
361 buffer += tsz;
362 buflen -= tsz;
363 *fpos += tsz;
364 }
365
366 /* ELF program headers. */
367 if (buflen && *fpos < phdrs_offset + phdrs_len) {
368 struct elf_phdr *phdrs, *phdr;
369
370 phdrs = kzalloc(phdrs_len, GFP_KERNEL);
371 if (!phdrs) {
372 ret = -ENOMEM;
373 goto out;
374 }
375
376 phdrs[0].p_type = PT_NOTE;
377 phdrs[0].p_offset = notes_offset;
378 phdrs[0].p_filesz = notes_len;
379
380 phdr = &phdrs[1];
381 list_for_each_entry(m, &kclist_head, list) {
382 phdr->p_type = PT_LOAD;
383 phdr->p_flags = PF_R | PF_W | PF_X;
384 phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
385 if (m->type == KCORE_REMAP)
386 phdr->p_vaddr = (size_t)m->vaddr;
387 else
388 phdr->p_vaddr = (size_t)m->addr;
389 if (m->type == KCORE_RAM || m->type == KCORE_REMAP)
390 phdr->p_paddr = __pa(m->addr);
391 else if (m->type == KCORE_TEXT)
392 phdr->p_paddr = __pa_symbol(m->addr);
393 else
394 phdr->p_paddr = (elf_addr_t)-1;
395 phdr->p_filesz = phdr->p_memsz = m->size;
396 phdr->p_align = PAGE_SIZE;
397 phdr++;
398 }
399
400 tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);
401 if (copy_to_user(buffer, (char *)phdrs + *fpos - phdrs_offset,
402 tsz)) {
403 kfree(phdrs);
404 ret = -EFAULT;
405 goto out;
406 }
407 kfree(phdrs);
408
409 buffer += tsz;
410 buflen -= tsz;
411 *fpos += tsz;
412 }
413
414 /* ELF note segment. */
415 if (buflen && *fpos < notes_offset + notes_len) {
416 struct elf_prstatus prstatus = {};
417 struct elf_prpsinfo prpsinfo = {
418 .pr_sname = 'R',
419 .pr_fname = "vmlinux",
420 };
421 char *notes;
422 size_t i = 0;
423
424 strlcpy(prpsinfo.pr_psargs, saved_command_line,
425 sizeof(prpsinfo.pr_psargs));
426
427 notes = kzalloc(notes_len, GFP_KERNEL);
428 if (!notes) {
429 ret = -ENOMEM;
430 goto out;
431 }
432
433 append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
434 sizeof(prstatus));
435 append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
436 sizeof(prpsinfo));
437 append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
438 arch_task_struct_size);
439 /*
440 * vmcoreinfo_size is mostly constant after init time, but it
441 * can be changed by crash_save_vmcoreinfo(). Racing here with a
442 * panic on another CPU before the machine goes down is insanely
443 * unlikely, but it's better to not leave potential buffer
444 * overflows lying around, regardless.
445 */
446 append_kcore_note(notes, &i, VMCOREINFO_NOTE_NAME, 0,
447 vmcoreinfo_data,
448 min(vmcoreinfo_size, notes_len - i));
449
450 tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos);
451 if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) {
452 kfree(notes);
453 ret = -EFAULT;
454 goto out;
455 }
456 kfree(notes);
457
458 buffer += tsz;
459 buflen -= tsz;
460 *fpos += tsz;
461 }
462
463 /*
464 * Check to see if our file offset matches with any of
465 * the addresses in the elf_phdr on our list.
466 */
467 start = kc_offset_to_vaddr(*fpos - data_offset);
468 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
469 tsz = buflen;
470
471 m = NULL;
472 while (buflen) {
473 /*
474 * If this is the first iteration or the address is not within
475 * the previous entry, search for a matching entry.
476 */
477 if (!m || start < m->addr || start >= m->addr + m->size) {
478 list_for_each_entry(m, &kclist_head, list) {
479 if (start >= m->addr &&
480 start < m->addr + m->size)
481 break;
482 }
483 }
484
485 if (&m->list == &kclist_head) {
486 if (clear_user(buffer, tsz)) {
487 ret = -EFAULT;
488 goto out;
489 }
490 m = NULL; /* skip the list anchor */
491 } else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
492 if (clear_user(buffer, tsz)) {
493 ret = -EFAULT;
494 goto out;
495 }
496 } else if (m->type == KCORE_VMALLOC) {
497 vread(buf, (char *)start, tsz);
498 /* we have to zero-fill user buffer even if no read */
499 if (copy_to_user(buffer, buf, tsz)) {
500 ret = -EFAULT;
501 goto out;
502 }
503 } else if (m->type == KCORE_USER) {
504 /* User page is handled prior to normal kernel page: */
505 if (copy_to_user(buffer, (char *)start, tsz)) {
506 ret = -EFAULT;
507 goto out;
508 }
509 } else {
510 if (kern_addr_valid(start)) {
511 /*
512 * Using bounce buffer to bypass the
513 * hardened user copy kernel text checks.
514 */
515 if (probe_kernel_read(buf, (void *) start, tsz)) {
516 if (clear_user(buffer, tsz)) {
517 ret = -EFAULT;
518 goto out;
519 }
520 } else {
521 if (copy_to_user(buffer, buf, tsz)) {
522 ret = -EFAULT;
523 goto out;
524 }
525 }
526 } else {
527 if (clear_user(buffer, tsz)) {
528 ret = -EFAULT;
529 goto out;
530 }
531 }
532 }
533 buflen -= tsz;
534 *fpos += tsz;
535 buffer += tsz;
536 start += tsz;
537 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
538 }
539
540out:
541 up_read(&kclist_lock);
542 if (ret)
543 return ret;
544 return orig_buflen - buflen;
545}
546
547static int open_kcore(struct inode *inode, struct file *filp)
548{
549 int ret = security_locked_down(LOCKDOWN_KCORE);
550
551 if (!capable(CAP_SYS_RAWIO))
552 return -EPERM;
553
554 if (ret)
555 return ret;
556
557 filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
558 if (!filp->private_data)
559 return -ENOMEM;
560
561 if (kcore_need_update)
562 kcore_update_ram();
563 if (i_size_read(inode) != proc_root_kcore->size) {
564 inode_lock(inode);
565 i_size_write(inode, proc_root_kcore->size);
566 inode_unlock(inode);
567 }
568 return 0;
569}
570
571static int release_kcore(struct inode *inode, struct file *file)
572{
573 kfree(file->private_data);
574 return 0;
575}
576
577static const struct file_operations proc_kcore_operations = {
578 .read = read_kcore,
579 .open = open_kcore,
580 .release = release_kcore,
581 .llseek = default_llseek,
582};
583
584/* just remember that we have to update kcore */
585static int __meminit kcore_callback(struct notifier_block *self,
586 unsigned long action, void *arg)
587{
588 switch (action) {
589 case MEM_ONLINE:
590 case MEM_OFFLINE:
591 kcore_need_update = 1;
592 break;
593 }
594 return NOTIFY_OK;
595}
596
597static struct notifier_block kcore_callback_nb __meminitdata = {
598 .notifier_call = kcore_callback,
599 .priority = 0,
600};
601
602static struct kcore_list kcore_vmalloc;
603
604#ifdef CONFIG_ARCH_PROC_KCORE_TEXT
605static struct kcore_list kcore_text;
606/*
607 * If defined, special segment is used for mapping kernel text instead of
608 * direct-map area. We need to create special TEXT section.
609 */
610static void __init proc_kcore_text_init(void)
611{
612 kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
613}
614#else
615static void __init proc_kcore_text_init(void)
616{
617}
618#endif
619
620#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
621/*
622 * MODULES_VADDR has no intersection with VMALLOC_ADDR.
623 */
624static struct kcore_list kcore_modules;
625static void __init add_modules_range(void)
626{
627 if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
628 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
629 MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
630 }
631}
632#else
633static void __init add_modules_range(void)
634{
635}
636#endif
637
638static int __init proc_kcore_init(void)
639{
640 proc_root_kcore = proc_create("kcore", S_IRUSR, NULL,
641 &proc_kcore_operations);
642 if (!proc_root_kcore) {
643 pr_err("couldn't create /proc/kcore\n");
644 return 0; /* Always returns 0. */
645 }
646 /* Store text area if it's special */
647 proc_kcore_text_init();
648 /* Store vmalloc area */
649 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
650 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
651 add_modules_range();
652 /* Store direct-map area from physical memory map */
653 kcore_update_ram();
654 register_hotmemory_notifier(&kcore_callback_nb);
655
656 return 0;
657}
658fs_initcall(proc_kcore_init);