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