2 * fs/proc/kcore.c kernel ELF core dumper
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>
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 <asm/uaccess.h>
24 #include <linux/list.h>
25 #include <linux/ioport.h>
27 #include <linux/memory.h>
28 #include <asm/sections.h>
30 #define CORE_STR "CORE"
32 #ifndef ELF_CORE_EFLAGS
33 #define ELF_CORE_EFLAGS 0
36 static struct proc_dir_entry *proc_root_kcore;
39 #ifndef kc_vaddr_to_offset
40 #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
42 #ifndef kc_offset_to_vaddr
43 #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
46 /* An ELF note in memory */
55 static LIST_HEAD(kclist_head);
56 static DEFINE_RWLOCK(kclist_lock);
57 static int kcore_need_update = 1;
60 kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
62 new->addr = (unsigned long)addr;
66 write_lock(&kclist_lock);
67 list_add_tail(&new->list, &kclist_head);
68 write_unlock(&kclist_lock);
71 static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
76 *nphdr = 1; /* PT_NOTE */
79 list_for_each_entry(m, &kclist_head, list) {
80 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
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;
96 static void free_kclist_ents(struct list_head *head)
98 struct kcore_list *tmp, *pos;
100 list_for_each_entry_safe(pos, tmp, head, list) {
101 list_del(&pos->list);
106 * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list.
108 static void __kcore_update_ram(struct list_head *list)
110 struct kcore_list *tmp, *pos;
113 write_lock(&kclist_lock);
114 if (kcore_need_update) {
115 list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
116 if (pos->type == KCORE_RAM
117 || pos->type == KCORE_VMEMMAP)
118 list_move(&pos->list, &garbage);
120 list_splice_tail(list, &kclist_head);
122 list_splice(list, &garbage);
123 kcore_need_update = 0;
124 write_unlock(&kclist_lock);
126 free_kclist_ents(&garbage);
130 #ifdef CONFIG_HIGHMEM
132 * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
133 * because memory hole is not as big as !HIGHMEM case.
134 * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
136 static int kcore_update_ram(void)
139 struct kcore_list *ent;
142 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
145 ent->addr = (unsigned long)__va(0);
146 ent->size = max_low_pfn << PAGE_SHIFT;
147 ent->type = KCORE_RAM;
148 list_add(&ent->list, &head);
149 __kcore_update_ram(&head);
153 #else /* !CONFIG_HIGHMEM */
155 #ifdef CONFIG_SPARSEMEM_VMEMMAP
156 /* calculate vmemmap's address from given system ram pfn and register it */
157 int get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
159 unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
160 unsigned long nr_pages = ent->size >> PAGE_SHIFT;
161 unsigned long start, end;
162 struct kcore_list *vmm, *tmp;
165 start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
166 end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
167 end = ALIGN(end, PAGE_SIZE);
168 /* overlap check (because we have to align page */
169 list_for_each_entry(tmp, head, list) {
170 if (tmp->type != KCORE_VMEMMAP)
172 if (start < tmp->addr + tmp->size)
177 vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
181 vmm->size = end - start;
182 vmm->type = KCORE_VMEMMAP;
183 list_add_tail(&vmm->list, head);
189 int get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
197 kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
199 struct list_head *head = (struct list_head *)arg;
200 struct kcore_list *ent;
202 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
205 ent->addr = (unsigned long)__va((pfn << PAGE_SHIFT));
206 ent->size = nr_pages << PAGE_SHIFT;
208 /* Sanity check: Can happen in 32bit arch...maybe */
209 if (ent->addr < (unsigned long) __va(0))
212 /* cut not-mapped area. ....from ppc-32 code. */
213 if (ULONG_MAX - ent->addr < ent->size)
214 ent->size = ULONG_MAX - ent->addr;
216 /* cut when vmalloc() area is higher than direct-map area */
217 if (VMALLOC_START > (unsigned long)__va(0)) {
218 if (ent->addr > VMALLOC_START)
220 if (VMALLOC_START - ent->addr < ent->size)
221 ent->size = VMALLOC_START - ent->addr;
224 ent->type = KCORE_RAM;
225 list_add_tail(&ent->list, head);
227 if (!get_sparsemem_vmemmap_info(ent, head)) {
228 list_del(&ent->list);
238 static int kcore_update_ram(void)
241 unsigned long end_pfn;
244 /* Not inialized....update now */
245 /* find out "max pfn" */
247 for_each_node_state(nid, N_HIGH_MEMORY) {
248 unsigned long node_end;
249 node_end = NODE_DATA(nid)->node_start_pfn +
250 NODE_DATA(nid)->node_spanned_pages;
251 if (end_pfn < node_end)
254 /* scan 0 to max_pfn */
255 ret = walk_system_ram_range(0, end_pfn, &head, kclist_add_private);
257 free_kclist_ents(&head);
260 __kcore_update_ram(&head);
263 #endif /* CONFIG_HIGHMEM */
265 /*****************************************************************************/
267 * determine size of ELF note
269 static int notesize(struct memelfnote *en)
273 sz = sizeof(struct elf_note);
274 sz += roundup((strlen(en->name) + 1), 4);
275 sz += roundup(en->datasz, 4);
278 } /* end notesize() */
280 /*****************************************************************************/
282 * store a note in the header buffer
284 static char *storenote(struct memelfnote *men, char *bufp)
288 #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
290 en.n_namesz = strlen(men->name) + 1;
291 en.n_descsz = men->datasz;
292 en.n_type = men->type;
294 DUMP_WRITE(&en, sizeof(en));
295 DUMP_WRITE(men->name, en.n_namesz);
297 /* XXX - cast from long long to long to avoid need for libgcc.a */
298 bufp = (char*) roundup((unsigned long)bufp,4);
299 DUMP_WRITE(men->data, men->datasz);
300 bufp = (char*) roundup((unsigned long)bufp,4);
305 } /* end storenote() */
308 * store an ELF coredump header in the supplied buffer
309 * nphdr is the number of elf_phdr to insert
311 static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
313 struct elf_prstatus prstatus; /* NT_PRSTATUS */
314 struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
315 struct elf_phdr *nhdr, *phdr;
317 struct memelfnote notes[3];
319 struct kcore_list *m;
321 /* setup ELF header */
322 elf = (struct elfhdr *) bufp;
323 bufp += sizeof(struct elfhdr);
324 offset += sizeof(struct elfhdr);
325 memcpy(elf->e_ident, ELFMAG, SELFMAG);
326 elf->e_ident[EI_CLASS] = ELF_CLASS;
327 elf->e_ident[EI_DATA] = ELF_DATA;
328 elf->e_ident[EI_VERSION]= EV_CURRENT;
329 elf->e_ident[EI_OSABI] = ELF_OSABI;
330 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
331 elf->e_type = ET_CORE;
332 elf->e_machine = ELF_ARCH;
333 elf->e_version = EV_CURRENT;
335 elf->e_phoff = sizeof(struct elfhdr);
337 elf->e_flags = ELF_CORE_EFLAGS;
338 elf->e_ehsize = sizeof(struct elfhdr);
339 elf->e_phentsize= sizeof(struct elf_phdr);
340 elf->e_phnum = nphdr;
345 /* setup ELF PT_NOTE program header */
346 nhdr = (struct elf_phdr *) bufp;
347 bufp += sizeof(struct elf_phdr);
348 offset += sizeof(struct elf_phdr);
349 nhdr->p_type = PT_NOTE;
358 /* setup ELF PT_LOAD program header for every area */
359 list_for_each_entry(m, &kclist_head, list) {
360 phdr = (struct elf_phdr *) bufp;
361 bufp += sizeof(struct elf_phdr);
362 offset += sizeof(struct elf_phdr);
364 phdr->p_type = PT_LOAD;
365 phdr->p_flags = PF_R|PF_W|PF_X;
366 phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
367 phdr->p_vaddr = (size_t)m->addr;
369 phdr->p_filesz = phdr->p_memsz = m->size;
370 phdr->p_align = PAGE_SIZE;
374 * Set up the notes in similar form to SVR4 core dumps made
375 * with info from their /proc.
377 nhdr->p_offset = offset;
379 /* set up the process status */
380 notes[0].name = CORE_STR;
381 notes[0].type = NT_PRSTATUS;
382 notes[0].datasz = sizeof(struct elf_prstatus);
383 notes[0].data = &prstatus;
385 memset(&prstatus, 0, sizeof(struct elf_prstatus));
387 nhdr->p_filesz = notesize(¬es[0]);
388 bufp = storenote(¬es[0], bufp);
390 /* set up the process info */
391 notes[1].name = CORE_STR;
392 notes[1].type = NT_PRPSINFO;
393 notes[1].datasz = sizeof(struct elf_prpsinfo);
394 notes[1].data = &prpsinfo;
396 memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
397 prpsinfo.pr_state = 0;
398 prpsinfo.pr_sname = 'R';
399 prpsinfo.pr_zomb = 0;
401 strcpy(prpsinfo.pr_fname, "vmlinux");
402 strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
404 nhdr->p_filesz += notesize(¬es[1]);
405 bufp = storenote(¬es[1], bufp);
407 /* set up the task structure */
408 notes[2].name = CORE_STR;
409 notes[2].type = NT_TASKSTRUCT;
410 notes[2].datasz = sizeof(struct task_struct);
411 notes[2].data = current;
413 nhdr->p_filesz += notesize(¬es[2]);
414 bufp = storenote(¬es[2], bufp);
416 } /* end elf_kcore_store_hdr() */
418 /*****************************************************************************/
420 * read from the ELF header and then kernel memory
423 read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
431 read_lock(&kclist_lock);
432 proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
433 if (buflen == 0 || *fpos >= size) {
434 read_unlock(&kclist_lock);
438 /* trim buflen to not go beyond EOF */
439 if (buflen > size - *fpos)
440 buflen = size - *fpos;
442 /* construct an ELF core header if we'll need some of it */
443 if (*fpos < elf_buflen) {
446 tsz = elf_buflen - *fpos;
449 elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
451 read_unlock(&kclist_lock);
454 elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
455 read_unlock(&kclist_lock);
456 if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
466 /* leave now if filled buffer already */
470 read_unlock(&kclist_lock);
473 * Check to see if our file offset matches with any of
474 * the addresses in the elf_phdr on our list.
476 start = kc_offset_to_vaddr(*fpos - elf_buflen);
477 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
481 struct kcore_list *m;
483 read_lock(&kclist_lock);
484 list_for_each_entry(m, &kclist_head, list) {
485 if (start >= m->addr && start < (m->addr+m->size))
488 read_unlock(&kclist_lock);
491 if (clear_user(buffer, tsz))
493 } else if (is_vmalloc_or_module_addr((void *)start)) {
496 elf_buf = kzalloc(tsz, GFP_KERNEL);
499 vread(elf_buf, (char *)start, tsz);
500 /* we have to zero-fill user buffer even if no read */
501 if (copy_to_user(buffer, elf_buf, tsz)) {
507 if (kern_addr_valid(start)) {
510 n = copy_to_user(buffer, (char *)start, tsz);
512 * We cannot distingush between fault on source
513 * and fault on destination. When this happens
514 * we clear too and hope it will trigger the
518 if (clear_user(buffer + tsz - n,
523 if (clear_user(buffer, tsz))
532 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
539 static int open_kcore(struct inode *inode, struct file *filp)
541 if (!capable(CAP_SYS_RAWIO))
543 if (kcore_need_update)
549 static const struct file_operations proc_kcore_operations = {
554 #ifdef CONFIG_MEMORY_HOTPLUG
555 /* just remember that we have to update kcore */
556 static int __meminit kcore_callback(struct notifier_block *self,
557 unsigned long action, void *arg)
562 write_lock(&kclist_lock);
563 kcore_need_update = 1;
564 write_unlock(&kclist_lock);
571 static struct kcore_list kcore_vmalloc;
573 #ifdef CONFIG_ARCH_PROC_KCORE_TEXT
574 static struct kcore_list kcore_text;
576 * If defined, special segment is used for mapping kernel text instead of
577 * direct-map area. We need to create special TEXT section.
579 static void __init proc_kcore_text_init(void)
581 kclist_add(&kcore_text, _stext, _end - _stext, KCORE_TEXT);
584 static void __init proc_kcore_text_init(void)
589 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
591 * MODULES_VADDR has no intersection with VMALLOC_ADDR.
593 struct kcore_list kcore_modules;
594 static void __init add_modules_range(void)
596 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
597 MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
600 static void __init add_modules_range(void)
605 static int __init proc_kcore_init(void)
607 proc_root_kcore = proc_create("kcore", S_IRUSR, NULL,
608 &proc_kcore_operations);
609 if (!proc_root_kcore) {
610 printk(KERN_ERR "couldn't create /proc/kcore\n");
611 return 0; /* Always returns 0. */
613 /* Store text area if it's special */
614 proc_kcore_text_init();
615 /* Store vmalloc area */
616 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
617 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
619 /* Store direct-map area from physical memory map */
621 hotplug_memory_notifier(kcore_callback, 0);
625 module_init(proc_kcore_init);