--- /dev/null
+/*
+ * fs/proc/kcore.c kernel ELF core dumper
+ *
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@sw.oz.au>
+ * ELF version written by David Howells <David.Howells@nexor.co.uk>
+ * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
+ * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
+ * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/kcore.h>
+#include <linux/user.h>
+#include <linux/capability.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/notifier.h>
+#include <linux/vmalloc.h>
+#include <linux/highmem.h>
+#include <linux/printk.h>
+#include <linux/bootmem.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <linux/list.h>
+#include <linux/ioport.h>
+#include <linux/memory.h>
+#include <asm/sections.h>
+#include "internal.h"
+
+#define CORE_STR "CORE"
+
+#ifndef ELF_CORE_EFLAGS
+#define ELF_CORE_EFLAGS 0
+#endif
+
+static struct proc_dir_entry *proc_root_kcore;
+
+
+#ifndef kc_vaddr_to_offset
+#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
+#endif
+#ifndef kc_offset_to_vaddr
+#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
+#endif
+
+/* An ELF note in memory */
+struct memelfnote
+{
+ const char *name;
+ int type;
+ unsigned int datasz;
+ void *data;
+};
+
+static LIST_HEAD(kclist_head);
+static DEFINE_RWLOCK(kclist_lock);
+static int kcore_need_update = 1;
+
+void
+kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
+{
+ new->addr = (unsigned long)addr;
+ new->size = size;
+ new->type = type;
+
+ write_lock(&kclist_lock);
+ list_add_tail(&new->list, &kclist_head);
+ write_unlock(&kclist_lock);
+}
+
+static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
+{
+ size_t try, size;
+ struct kcore_list *m;
+
+ *nphdr = 1; /* PT_NOTE */
+ size = 0;
+
+ list_for_each_entry(m, &kclist_head, list) {
+ try = kc_vaddr_to_offset((size_t)m->addr + m->size);
+ if (try > size)
+ size = try;
+ *nphdr = *nphdr + 1;
+ }
+ *elf_buflen = sizeof(struct elfhdr) +
+ (*nphdr + 2)*sizeof(struct elf_phdr) +
+ 3 * ((sizeof(struct elf_note)) +
+ roundup(sizeof(CORE_STR), 4)) +
+ roundup(sizeof(struct elf_prstatus), 4) +
+ roundup(sizeof(struct elf_prpsinfo), 4) +
+ roundup(sizeof(struct task_struct), 4);
+ *elf_buflen = PAGE_ALIGN(*elf_buflen);
+ return size + *elf_buflen;
+}
+
+static void free_kclist_ents(struct list_head *head)
+{
+ struct kcore_list *tmp, *pos;
+
+ list_for_each_entry_safe(pos, tmp, head, list) {
+ list_del(&pos->list);
+ kfree(pos);
+ }
+}
+/*
+ * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list.
+ */
+static void __kcore_update_ram(struct list_head *list)
+{
+ int nphdr;
+ size_t size;
+ struct kcore_list *tmp, *pos;
+ LIST_HEAD(garbage);
+
+ write_lock(&kclist_lock);
+ if (kcore_need_update) {
+ list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
+ if (pos->type == KCORE_RAM
+ || pos->type == KCORE_VMEMMAP)
+ list_move(&pos->list, &garbage);
+ }
+ list_splice_tail(list, &kclist_head);
+ } else
+ list_splice(list, &garbage);
+ kcore_need_update = 0;
+ proc_root_kcore->size = get_kcore_size(&nphdr, &size);
+ write_unlock(&kclist_lock);
+
+ free_kclist_ents(&garbage);
+}
+
+
+#ifdef CONFIG_HIGHMEM
+/*
+ * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
+ * because memory hole is not as big as !HIGHMEM case.
+ * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
+ */
+static int kcore_update_ram(void)
+{
+ LIST_HEAD(head);
+ struct kcore_list *ent;
+ int ret = 0;
+
+ ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+ ent->addr = (unsigned long)__va(0);
+ ent->size = max_low_pfn << PAGE_SHIFT;
+ ent->type = KCORE_RAM;
+ list_add(&ent->list, &head);
+ __kcore_update_ram(&head);
+ return ret;
+}
+
+#else /* !CONFIG_HIGHMEM */
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+/* calculate vmemmap's address from given system ram pfn and register it */
+static int
+get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+ unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
+ unsigned long nr_pages = ent->size >> PAGE_SHIFT;
+ unsigned long start, end;
+ struct kcore_list *vmm, *tmp;
+
+
+ start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
+ end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
+ end = PAGE_ALIGN(end);
+ /* overlap check (because we have to align page */
+ list_for_each_entry(tmp, head, list) {
+ if (tmp->type != KCORE_VMEMMAP)
+ continue;
+ if (start < tmp->addr + tmp->size)
+ if (end > tmp->addr)
+ end = tmp->addr;
+ }
+ if (start < end) {
+ vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
+ if (!vmm)
+ return 0;
+ vmm->addr = start;
+ vmm->size = end - start;
+ vmm->type = KCORE_VMEMMAP;
+ list_add_tail(&vmm->list, head);
+ }
+ return 1;
+
+}
+#else
+static int
+get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+ return 1;
+}
+
+#endif
+
+static int
+kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
+{
+ struct list_head *head = (struct list_head *)arg;
+ struct kcore_list *ent;
+
+ ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+ ent->addr = (unsigned long)__va((pfn << PAGE_SHIFT));
+ ent->size = nr_pages << PAGE_SHIFT;
+
+ /* Sanity check: Can happen in 32bit arch...maybe */
+ if (ent->addr < (unsigned long) __va(0))
+ goto free_out;
+
+ /* cut not-mapped area. ....from ppc-32 code. */
+ if (ULONG_MAX - ent->addr < ent->size)
+ ent->size = ULONG_MAX - ent->addr;
+
+ /* cut when vmalloc() area is higher than direct-map area */
+ if (VMALLOC_START > (unsigned long)__va(0)) {
+ if (ent->addr > VMALLOC_START)
+ goto free_out;
+ if (VMALLOC_START - ent->addr < ent->size)
+ ent->size = VMALLOC_START - ent->addr;
+ }
+
+ ent->type = KCORE_RAM;
+ list_add_tail(&ent->list, head);
+
+ if (!get_sparsemem_vmemmap_info(ent, head)) {
+ list_del(&ent->list);
+ goto free_out;
+ }
+
+ return 0;
+free_out:
+ kfree(ent);
+ return 1;
+}
+
+static int kcore_update_ram(void)
+{
+ int nid, ret;
+ unsigned long end_pfn;
+ LIST_HEAD(head);
+
+ /* Not inialized....update now */
+ /* find out "max pfn" */
+ end_pfn = 0;
+ for_each_node_state(nid, N_MEMORY) {
+ unsigned long node_end;
+ node_end = node_end_pfn(nid);
+ if (end_pfn < node_end)
+ end_pfn = node_end;
+ }
+ /* scan 0 to max_pfn */
+ ret = walk_system_ram_range(0, end_pfn, &head, kclist_add_private);
+ if (ret) {
+ free_kclist_ents(&head);
+ return -ENOMEM;
+ }
+ __kcore_update_ram(&head);
+ return ret;
+}
+#endif /* CONFIG_HIGHMEM */
+
+/*****************************************************************************/
+/*
+ * determine size of ELF note
+ */
+static int notesize(struct memelfnote *en)
+{
+ int sz;
+
+ sz = sizeof(struct elf_note);
+ sz += roundup((strlen(en->name) + 1), 4);
+ sz += roundup(en->datasz, 4);
+
+ return sz;
+} /* end notesize() */
+
+/*****************************************************************************/
+/*
+ * store a note in the header buffer
+ */
+static char *storenote(struct memelfnote *men, char *bufp)
+{
+ struct elf_note en;
+
+#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
+
+ en.n_namesz = strlen(men->name) + 1;
+ en.n_descsz = men->datasz;
+ en.n_type = men->type;
+
+ DUMP_WRITE(&en, sizeof(en));
+ DUMP_WRITE(men->name, en.n_namesz);
+
+ /* XXX - cast from long long to long to avoid need for libgcc.a */
+ bufp = (char*) roundup((unsigned long)bufp,4);
+ DUMP_WRITE(men->data, men->datasz);
+ bufp = (char*) roundup((unsigned long)bufp,4);
+
+#undef DUMP_WRITE
+
+ return bufp;
+} /* end storenote() */
+
+/*
+ * store an ELF coredump header in the supplied buffer
+ * nphdr is the number of elf_phdr to insert
+ */
+static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
+{
+ struct elf_prstatus prstatus; /* NT_PRSTATUS */
+ struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
+ struct elf_phdr *nhdr, *phdr;
+ struct elfhdr *elf;
+ struct memelfnote notes[3];
+ off_t offset = 0;
+ struct kcore_list *m;
+
+ /* setup ELF header */
+ elf = (struct elfhdr *) bufp;
+ bufp += sizeof(struct elfhdr);
+ offset += sizeof(struct elfhdr);
+ memcpy(elf->e_ident, ELFMAG, SELFMAG);
+ elf->e_ident[EI_CLASS] = ELF_CLASS;
+ elf->e_ident[EI_DATA] = ELF_DATA;
+ elf->e_ident[EI_VERSION]= EV_CURRENT;
+ elf->e_ident[EI_OSABI] = ELF_OSABI;
+ memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
+ elf->e_type = ET_CORE;
+ elf->e_machine = ELF_ARCH;
+ elf->e_version = EV_CURRENT;
+ elf->e_entry = 0;
+ elf->e_phoff = sizeof(struct elfhdr);
+ elf->e_shoff = 0;
+ elf->e_flags = ELF_CORE_EFLAGS;
+ elf->e_ehsize = sizeof(struct elfhdr);
+ elf->e_phentsize= sizeof(struct elf_phdr);
+ elf->e_phnum = nphdr;
+ elf->e_shentsize= 0;
+ elf->e_shnum = 0;
+ elf->e_shstrndx = 0;
+
+ /* setup ELF PT_NOTE program header */
+ nhdr = (struct elf_phdr *) bufp;
+ bufp += sizeof(struct elf_phdr);
+ offset += sizeof(struct elf_phdr);
+ nhdr->p_type = PT_NOTE;
+ nhdr->p_offset = 0;
+ nhdr->p_vaddr = 0;
+ nhdr->p_paddr = 0;
+ nhdr->p_filesz = 0;
+ nhdr->p_memsz = 0;
+ nhdr->p_flags = 0;
+ nhdr->p_align = 0;
+
+ /* setup ELF PT_LOAD program header for every area */
+ list_for_each_entry(m, &kclist_head, list) {
+ phdr = (struct elf_phdr *) bufp;
+ bufp += sizeof(struct elf_phdr);
+ offset += sizeof(struct elf_phdr);
+
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R|PF_W|PF_X;
+ phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
+ phdr->p_vaddr = (size_t)m->addr;
+ phdr->p_paddr = 0;
+ phdr->p_filesz = phdr->p_memsz = m->size;
+ phdr->p_align = PAGE_SIZE;
+ }
+
+ /*
+ * Set up the notes in similar form to SVR4 core dumps made
+ * with info from their /proc.
+ */
+ nhdr->p_offset = offset;
+
+ /* set up the process status */
+ notes[0].name = CORE_STR;
+ notes[0].type = NT_PRSTATUS;
+ notes[0].datasz = sizeof(struct elf_prstatus);
+ notes[0].data = &prstatus;
+
+ memset(&prstatus, 0, sizeof(struct elf_prstatus));
+
+ nhdr->p_filesz = notesize(¬es[0]);
+ bufp = storenote(¬es[0], bufp);
+
+ /* set up the process info */
+ notes[1].name = CORE_STR;
+ notes[1].type = NT_PRPSINFO;
+ notes[1].datasz = sizeof(struct elf_prpsinfo);
+ notes[1].data = &prpsinfo;
+
+ memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
+ prpsinfo.pr_state = 0;
+ prpsinfo.pr_sname = 'R';
+ prpsinfo.pr_zomb = 0;
+
+ strcpy(prpsinfo.pr_fname, "vmlinux");
+ strlcpy(prpsinfo.pr_psargs, saved_command_line, sizeof(prpsinfo.pr_psargs));
+
+ nhdr->p_filesz += notesize(¬es[1]);
+ bufp = storenote(¬es[1], bufp);
+
+ /* set up the task structure */
+ notes[2].name = CORE_STR;
+ notes[2].type = NT_TASKSTRUCT;
+ notes[2].datasz = sizeof(struct task_struct);
+ notes[2].data = current;
+
+ nhdr->p_filesz += notesize(¬es[2]);
+ bufp = storenote(¬es[2], bufp);
+
+} /* end elf_kcore_store_hdr() */
+
+/*****************************************************************************/
+/*
+ * read from the ELF header and then kernel memory
+ */
+static ssize_t
+read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
+{
+ ssize_t acc = 0;
+ size_t size, tsz;
+ size_t elf_buflen;
+ int nphdr;
+ unsigned long start;
+
+ read_lock(&kclist_lock);
+ size = get_kcore_size(&nphdr, &elf_buflen);
+
+ if (buflen == 0 || *fpos >= size) {
+ read_unlock(&kclist_lock);
+ return 0;
+ }
+
+ /* trim buflen to not go beyond EOF */
+ if (buflen > size - *fpos)
+ buflen = size - *fpos;
+
+ /* construct an ELF core header if we'll need some of it */
+ if (*fpos < elf_buflen) {
+ char * elf_buf;
+
+ tsz = elf_buflen - *fpos;
+ if (buflen < tsz)
+ tsz = buflen;
+ elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
+ if (!elf_buf) {
+ read_unlock(&kclist_lock);
+ return -ENOMEM;
+ }
+ elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
+ read_unlock(&kclist_lock);
+ if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
+ kfree(elf_buf);
+ return -EFAULT;
+ }
+ kfree(elf_buf);
+ buflen -= tsz;
+ *fpos += tsz;
+ buffer += tsz;
+ acc += tsz;
+
+ /* leave now if filled buffer already */
+ if (buflen == 0)
+ return acc;
+ } else
+ read_unlock(&kclist_lock);
+
+ /*
+ * Check to see if our file offset matches with any of
+ * the addresses in the elf_phdr on our list.
+ */
+ start = kc_offset_to_vaddr(*fpos - elf_buflen);
+ if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
+ tsz = buflen;
+
+ while (buflen) {
+ struct kcore_list *m;
+
+ read_lock(&kclist_lock);
+ list_for_each_entry(m, &kclist_head, list) {
+ if (start >= m->addr && start < (m->addr+m->size))
+ break;
+ }
+ read_unlock(&kclist_lock);
+
+ if (&m->list == &kclist_head) {
+ if (clear_user(buffer, tsz))
+ return -EFAULT;
+ } else if (is_vmalloc_or_module_addr((void *)start)) {
+ char * elf_buf;
+
+ elf_buf = kzalloc(tsz, GFP_KERNEL);
+ if (!elf_buf)
+ return -ENOMEM;
+ vread(elf_buf, (char *)start, tsz);
+ /* we have to zero-fill user buffer even if no read */
+ if (copy_to_user(buffer, elf_buf, tsz)) {
+ kfree(elf_buf);
+ return -EFAULT;
+ }
+ kfree(elf_buf);
+ } else {
+ if (kern_addr_valid(start)) {
+ unsigned long n;
+
+ n = copy_to_user(buffer, (char *)start, tsz);
+ /*
+ * We cannot distinguish between fault on source
+ * and fault on destination. When this happens
+ * we clear too and hope it will trigger the
+ * EFAULT again.
+ */
+ if (n) {
+ if (clear_user(buffer + tsz - n,
+ n))
+ return -EFAULT;
+ }
+ } else {
+ if (clear_user(buffer, tsz))
+ return -EFAULT;
+ }
+ }
+ buflen -= tsz;
+ *fpos += tsz;
+ buffer += tsz;
+ acc += tsz;
+ start += tsz;
+ tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
+ }
+
+ return acc;
+}
+
+
+static int open_kcore(struct inode *inode, struct file *filp)
+{
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+ if (kcore_need_update)
+ kcore_update_ram();
+ if (i_size_read(inode) != proc_root_kcore->size) {
+ mutex_lock(&inode->i_mutex);
+ i_size_write(inode, proc_root_kcore->size);
+ mutex_unlock(&inode->i_mutex);
+ }
+ return 0;
+}
+
+
+static const struct file_operations proc_kcore_operations = {
+ .read = read_kcore,
+ .open = open_kcore,
+ .llseek = default_llseek,
+};
+
+/* just remember that we have to update kcore */
+static int __meminit kcore_callback(struct notifier_block *self,
+ unsigned long action, void *arg)
+{
+ switch (action) {
+ case MEM_ONLINE:
+ case MEM_OFFLINE:
+ write_lock(&kclist_lock);
+ kcore_need_update = 1;
+ write_unlock(&kclist_lock);
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block kcore_callback_nb __meminitdata = {
+ .notifier_call = kcore_callback,
+ .priority = 0,
+};
+
+static struct kcore_list kcore_vmalloc;
+
+#ifdef CONFIG_ARCH_PROC_KCORE_TEXT
+static struct kcore_list kcore_text;
+/*
+ * If defined, special segment is used for mapping kernel text instead of
+ * direct-map area. We need to create special TEXT section.
+ */
+static void __init proc_kcore_text_init(void)
+{
+ kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
+}
+#else
+static void __init proc_kcore_text_init(void)
+{
+}
+#endif
+
+#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
+/*
+ * MODULES_VADDR has no intersection with VMALLOC_ADDR.
+ */
+struct kcore_list kcore_modules;
+static void __init add_modules_range(void)
+{
+ if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
+ kclist_add(&kcore_modules, (void *)MODULES_VADDR,
+ MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
+ }
+}
+#else
+static void __init add_modules_range(void)
+{
+}
+#endif
+
+static int __init proc_kcore_init(void)
+{
+ proc_root_kcore = proc_create("kcore", S_IRUSR, NULL,
+ &proc_kcore_operations);
+ if (!proc_root_kcore) {
+ pr_err("couldn't create /proc/kcore\n");
+ return 0; /* Always returns 0. */
+ }
+ /* Store text area if it's special */
+ proc_kcore_text_init();
+ /* Store vmalloc area */
+ kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
+ VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
+ add_modules_range();
+ /* Store direct-map area from physical memory map */
+ kcore_update_ram();
+ register_hotmemory_notifier(&kcore_callback_nb);
+
+ return 0;
+}
+fs_initcall(proc_kcore_init);
Code Review / kvmfornfv.git / blobdiff