--- /dev/null
+/*
+ * fs/proc/vmcore.c Interface for accessing the crash
+ * dump from the system's previous life.
+ * Heavily borrowed from fs/proc/kcore.c
+ * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
+ * Copyright (C) IBM Corporation, 2004. All rights reserved
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/kcore.h>
+#include <linux/user.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/printk.h>
+#include <linux/bootmem.h>
+#include <linux/init.h>
+#include <linux/crash_dump.h>
+#include <linux/list.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include "internal.h"
+
+/* List representing chunks of contiguous memory areas and their offsets in
+ * vmcore file.
+ */
+static LIST_HEAD(vmcore_list);
+
+/* Stores the pointer to the buffer containing kernel elf core headers. */
+static char *elfcorebuf;
+static size_t elfcorebuf_sz;
+static size_t elfcorebuf_sz_orig;
+
+static char *elfnotes_buf;
+static size_t elfnotes_sz;
+
+/* Total size of vmcore file. */
+static u64 vmcore_size;
+
+static struct proc_dir_entry *proc_vmcore;
+
+/*
+ * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
+ * The called function has to take care of module refcounting.
+ */
+static int (*oldmem_pfn_is_ram)(unsigned long pfn);
+
+int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
+{
+ if (oldmem_pfn_is_ram)
+ return -EBUSY;
+ oldmem_pfn_is_ram = fn;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
+
+void unregister_oldmem_pfn_is_ram(void)
+{
+ oldmem_pfn_is_ram = NULL;
+ wmb();
+}
+EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
+
+static int pfn_is_ram(unsigned long pfn)
+{
+ int (*fn)(unsigned long pfn);
+ /* pfn is ram unless fn() checks pagetype */
+ int ret = 1;
+
+ /*
+ * Ask hypervisor if the pfn is really ram.
+ * A ballooned page contains no data and reading from such a page
+ * will cause high load in the hypervisor.
+ */
+ fn = oldmem_pfn_is_ram;
+ if (fn)
+ ret = fn(pfn);
+
+ return ret;
+}
+
+/* Reads a page from the oldmem device from given offset. */
+static ssize_t read_from_oldmem(char *buf, size_t count,
+ u64 *ppos, int userbuf)
+{
+ unsigned long pfn, offset;
+ size_t nr_bytes;
+ ssize_t read = 0, tmp;
+
+ if (!count)
+ return 0;
+
+ offset = (unsigned long)(*ppos % PAGE_SIZE);
+ pfn = (unsigned long)(*ppos / PAGE_SIZE);
+
+ do {
+ if (count > (PAGE_SIZE - offset))
+ nr_bytes = PAGE_SIZE - offset;
+ else
+ nr_bytes = count;
+
+ /* If pfn is not ram, return zeros for sparse dump files */
+ if (pfn_is_ram(pfn) == 0)
+ memset(buf, 0, nr_bytes);
+ else {
+ tmp = copy_oldmem_page(pfn, buf, nr_bytes,
+ offset, userbuf);
+ if (tmp < 0)
+ return tmp;
+ }
+ *ppos += nr_bytes;
+ count -= nr_bytes;
+ buf += nr_bytes;
+ read += nr_bytes;
+ ++pfn;
+ offset = 0;
+ } while (count);
+
+ return read;
+}
+
+/*
+ * Architectures may override this function to allocate ELF header in 2nd kernel
+ */
+int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
+{
+ return 0;
+}
+
+/*
+ * Architectures may override this function to free header
+ */
+void __weak elfcorehdr_free(unsigned long long addr)
+{}
+
+/*
+ * Architectures may override this function to read from ELF header
+ */
+ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+ return read_from_oldmem(buf, count, ppos, 0);
+}
+
+/*
+ * Architectures may override this function to read from notes sections
+ */
+ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
+{
+ return read_from_oldmem(buf, count, ppos, 0);
+}
+
+/*
+ * Architectures may override this function to map oldmem
+ */
+int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
+ unsigned long from, unsigned long pfn,
+ unsigned long size, pgprot_t prot)
+{
+ return remap_pfn_range(vma, from, pfn, size, prot);
+}
+
+/*
+ * Copy to either kernel or user space
+ */
+static int copy_to(void *target, void *src, size_t size, int userbuf)
+{
+ if (userbuf) {
+ if (copy_to_user((char __user *) target, src, size))
+ return -EFAULT;
+ } else {
+ memcpy(target, src, size);
+ }
+ return 0;
+}
+
+/* Read from the ELF header and then the crash dump. On error, negative value is
+ * returned otherwise number of bytes read are returned.
+ */
+static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
+ int userbuf)
+{
+ ssize_t acc = 0, tmp;
+ size_t tsz;
+ u64 start;
+ struct vmcore *m = NULL;
+
+ if (buflen == 0 || *fpos >= vmcore_size)
+ return 0;
+
+ /* trim buflen to not go beyond EOF */
+ if (buflen > vmcore_size - *fpos)
+ buflen = vmcore_size - *fpos;
+
+ /* Read ELF core header */
+ if (*fpos < elfcorebuf_sz) {
+ tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
+ if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
+ return -EFAULT;
+ buflen -= tsz;
+ *fpos += tsz;
+ buffer += tsz;
+ acc += tsz;
+
+ /* leave now if filled buffer already */
+ if (buflen == 0)
+ return acc;
+ }
+
+ /* Read Elf note segment */
+ if (*fpos < elfcorebuf_sz + elfnotes_sz) {
+ void *kaddr;
+
+ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
+ kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
+ if (copy_to(buffer, kaddr, tsz, userbuf))
+ return -EFAULT;
+ buflen -= tsz;
+ *fpos += tsz;
+ buffer += tsz;
+ acc += tsz;
+
+ /* leave now if filled buffer already */
+ if (buflen == 0)
+ return acc;
+ }
+
+ list_for_each_entry(m, &vmcore_list, list) {
+ if (*fpos < m->offset + m->size) {
+ tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
+ start = m->paddr + *fpos - m->offset;
+ tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
+ if (tmp < 0)
+ return tmp;
+ buflen -= tsz;
+ *fpos += tsz;
+ buffer += tsz;
+ acc += tsz;
+
+ /* leave now if filled buffer already */
+ if (buflen == 0)
+ return acc;
+ }
+ }
+
+ return acc;
+}
+
+static ssize_t read_vmcore(struct file *file, char __user *buffer,
+ size_t buflen, loff_t *fpos)
+{
+ return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
+}
+
+/*
+ * The vmcore fault handler uses the page cache and fills data using the
+ * standard __vmcore_read() function.
+ *
+ * On s390 the fault handler is used for memory regions that can't be mapped
+ * directly with remap_pfn_range().
+ */
+static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+#ifdef CONFIG_S390
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ pgoff_t index = vmf->pgoff;
+ struct page *page;
+ loff_t offset;
+ char *buf;
+ int rc;
+
+ page = find_or_create_page(mapping, index, GFP_KERNEL);
+ if (!page)
+ return VM_FAULT_OOM;
+ if (!PageUptodate(page)) {
+ offset = (loff_t) index << PAGE_CACHE_SHIFT;
+ buf = __va((page_to_pfn(page) << PAGE_SHIFT));
+ rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
+ if (rc < 0) {
+ unlock_page(page);
+ page_cache_release(page);
+ return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
+ }
+ SetPageUptodate(page);
+ }
+ unlock_page(page);
+ vmf->page = page;
+ return 0;
+#else
+ return VM_FAULT_SIGBUS;
+#endif
+}
+
+static const struct vm_operations_struct vmcore_mmap_ops = {
+ .fault = mmap_vmcore_fault,
+};
+
+/**
+ * alloc_elfnotes_buf - allocate buffer for ELF note segment in
+ * vmalloc memory
+ *
+ * @notes_sz: size of buffer
+ *
+ * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
+ * the buffer to user-space by means of remap_vmalloc_range().
+ *
+ * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
+ * disabled and there's no need to allow users to mmap the buffer.
+ */
+static inline char *alloc_elfnotes_buf(size_t notes_sz)
+{
+#ifdef CONFIG_MMU
+ return vmalloc_user(notes_sz);
+#else
+ return vzalloc(notes_sz);
+#endif
+}
+
+/*
+ * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
+ * essential for mmap_vmcore() in order to map physically
+ * non-contiguous objects (ELF header, ELF note segment and memory
+ * regions in the 1st kernel pointed to by PT_LOAD entries) into
+ * virtually contiguous user-space in ELF layout.
+ */
+#ifdef CONFIG_MMU
+/*
+ * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
+ * reported as not being ram with the zero page.
+ *
+ * @vma: vm_area_struct describing requested mapping
+ * @from: start remapping from
+ * @pfn: page frame number to start remapping to
+ * @size: remapping size
+ * @prot: protection bits
+ *
+ * Returns zero on success, -EAGAIN on failure.
+ */
+static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
+ unsigned long from, unsigned long pfn,
+ unsigned long size, pgprot_t prot)
+{
+ unsigned long map_size;
+ unsigned long pos_start, pos_end, pos;
+ unsigned long zeropage_pfn = my_zero_pfn(0);
+ size_t len = 0;
+
+ pos_start = pfn;
+ pos_end = pfn + (size >> PAGE_SHIFT);
+
+ for (pos = pos_start; pos < pos_end; ++pos) {
+ if (!pfn_is_ram(pos)) {
+ /*
+ * We hit a page which is not ram. Remap the continuous
+ * region between pos_start and pos-1 and replace
+ * the non-ram page at pos with the zero page.
+ */
+ if (pos > pos_start) {
+ /* Remap continuous region */
+ map_size = (pos - pos_start) << PAGE_SHIFT;
+ if (remap_oldmem_pfn_range(vma, from + len,
+ pos_start, map_size,
+ prot))
+ goto fail;
+ len += map_size;
+ }
+ /* Remap the zero page */
+ if (remap_oldmem_pfn_range(vma, from + len,
+ zeropage_pfn,
+ PAGE_SIZE, prot))
+ goto fail;
+ len += PAGE_SIZE;
+ pos_start = pos + 1;
+ }
+ }
+ if (pos > pos_start) {
+ /* Remap the rest */
+ map_size = (pos - pos_start) << PAGE_SHIFT;
+ if (remap_oldmem_pfn_range(vma, from + len, pos_start,
+ map_size, prot))
+ goto fail;
+ }
+ return 0;
+fail:
+ do_munmap(vma->vm_mm, from, len);
+ return -EAGAIN;
+}
+
+static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
+ unsigned long from, unsigned long pfn,
+ unsigned long size, pgprot_t prot)
+{
+ /*
+ * Check if oldmem_pfn_is_ram was registered to avoid
+ * looping over all pages without a reason.
+ */
+ if (oldmem_pfn_is_ram)
+ return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
+ else
+ return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
+}
+
+static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
+{
+ size_t size = vma->vm_end - vma->vm_start;
+ u64 start, end, len, tsz;
+ struct vmcore *m;
+
+ start = (u64)vma->vm_pgoff << PAGE_SHIFT;
+ end = start + size;
+
+ if (size > vmcore_size || end > vmcore_size)
+ return -EINVAL;
+
+ if (vma->vm_flags & (VM_WRITE | VM_EXEC))
+ return -EPERM;
+
+ vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
+ vma->vm_flags |= VM_MIXEDMAP;
+ vma->vm_ops = &vmcore_mmap_ops;
+
+ len = 0;
+
+ if (start < elfcorebuf_sz) {
+ u64 pfn;
+
+ tsz = min(elfcorebuf_sz - (size_t)start, size);
+ pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
+ if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
+ vma->vm_page_prot))
+ return -EAGAIN;
+ size -= tsz;
+ start += tsz;
+ len += tsz;
+
+ if (size == 0)
+ return 0;
+ }
+
+ if (start < elfcorebuf_sz + elfnotes_sz) {
+ void *kaddr;
+
+ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
+ kaddr = elfnotes_buf + start - elfcorebuf_sz;
+ if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
+ kaddr, tsz))
+ goto fail;
+ size -= tsz;
+ start += tsz;
+ len += tsz;
+
+ if (size == 0)
+ return 0;
+ }
+
+ list_for_each_entry(m, &vmcore_list, list) {
+ if (start < m->offset + m->size) {
+ u64 paddr = 0;
+
+ tsz = min_t(size_t, m->offset + m->size - start, size);
+ paddr = m->paddr + start - m->offset;
+ if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
+ paddr >> PAGE_SHIFT, tsz,
+ vma->vm_page_prot))
+ goto fail;
+ size -= tsz;
+ start += tsz;
+ len += tsz;
+
+ if (size == 0)
+ return 0;
+ }
+ }
+
+ return 0;
+fail:
+ do_munmap(vma->vm_mm, vma->vm_start, len);
+ return -EAGAIN;
+}
+#else
+static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
+{
+ return -ENOSYS;
+}
+#endif
+
+static const struct file_operations proc_vmcore_operations = {
+ .read = read_vmcore,
+ .llseek = default_llseek,
+ .mmap = mmap_vmcore,
+};
+
+static struct vmcore* __init get_new_element(void)
+{
+ return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
+}
+
+static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
+ struct list_head *vc_list)
+{
+ u64 size;
+ struct vmcore *m;
+
+ size = elfsz + elfnotesegsz;
+ list_for_each_entry(m, vc_list, list) {
+ size += m->size;
+ }
+ return size;
+}
+
+/**
+ * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
+ *
+ * @ehdr_ptr: ELF header
+ *
+ * This function updates p_memsz member of each PT_NOTE entry in the
+ * program header table pointed to by @ehdr_ptr to real size of ELF
+ * note segment.
+ */
+static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
+{
+ int i, rc=0;
+ Elf64_Phdr *phdr_ptr;
+ Elf64_Nhdr *nhdr_ptr;
+
+ phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ void *notes_section;
+ u64 offset, max_sz, sz, real_sz = 0;
+ if (phdr_ptr->p_type != PT_NOTE)
+ continue;
+ max_sz = phdr_ptr->p_memsz;
+ offset = phdr_ptr->p_offset;
+ notes_section = kmalloc(max_sz, GFP_KERNEL);
+ if (!notes_section)
+ return -ENOMEM;
+ rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
+ if (rc < 0) {
+ kfree(notes_section);
+ return rc;
+ }
+ nhdr_ptr = notes_section;
+ while (nhdr_ptr->n_namesz != 0) {
+ sz = sizeof(Elf64_Nhdr) +
+ (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
+ (((u64)nhdr_ptr->n_descsz + 3) & ~3);
+ if ((real_sz + sz) > max_sz) {
+ pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
+ nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
+ break;
+ }
+ real_sz += sz;
+ nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
+ }
+ kfree(notes_section);
+ phdr_ptr->p_memsz = real_sz;
+ if (real_sz == 0) {
+ pr_warn("Warning: Zero PT_NOTE entries found\n");
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * get_note_number_and_size_elf64 - get the number of PT_NOTE program
+ * headers and sum of real size of their ELF note segment headers and
+ * data.
+ *
+ * @ehdr_ptr: ELF header
+ * @nr_ptnote: buffer for the number of PT_NOTE program headers
+ * @sz_ptnote: buffer for size of unique PT_NOTE program header
+ *
+ * This function is used to merge multiple PT_NOTE program headers
+ * into a unique single one. The resulting unique entry will have
+ * @sz_ptnote in its phdr->p_mem.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf64
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
+ int *nr_ptnote, u64 *sz_ptnote)
+{
+ int i;
+ Elf64_Phdr *phdr_ptr;
+
+ *nr_ptnote = *sz_ptnote = 0;
+
+ phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ if (phdr_ptr->p_type != PT_NOTE)
+ continue;
+ *nr_ptnote += 1;
+ *sz_ptnote += phdr_ptr->p_memsz;
+ }
+
+ return 0;
+}
+
+/**
+ * copy_notes_elf64 - copy ELF note segments in a given buffer
+ *
+ * @ehdr_ptr: ELF header
+ * @notes_buf: buffer into which ELF note segments are copied
+ *
+ * This function is used to copy ELF note segment in the 1st kernel
+ * into the buffer @notes_buf in the 2nd kernel. It is assumed that
+ * size of the buffer @notes_buf is equal to or larger than sum of the
+ * real ELF note segment headers and data.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf64
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
+{
+ int i, rc=0;
+ Elf64_Phdr *phdr_ptr;
+
+ phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
+
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ u64 offset;
+ if (phdr_ptr->p_type != PT_NOTE)
+ continue;
+ offset = phdr_ptr->p_offset;
+ rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
+ &offset);
+ if (rc < 0)
+ return rc;
+ notes_buf += phdr_ptr->p_memsz;
+ }
+
+ return 0;
+}
+
+/* Merges all the PT_NOTE headers into one. */
+static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
+ char **notes_buf, size_t *notes_sz)
+{
+ int i, nr_ptnote=0, rc=0;
+ char *tmp;
+ Elf64_Ehdr *ehdr_ptr;
+ Elf64_Phdr phdr;
+ u64 phdr_sz = 0, note_off;
+
+ ehdr_ptr = (Elf64_Ehdr *)elfptr;
+
+ rc = update_note_header_size_elf64(ehdr_ptr);
+ if (rc < 0)
+ return rc;
+
+ rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
+ if (rc < 0)
+ return rc;
+
+ *notes_sz = roundup(phdr_sz, PAGE_SIZE);
+ *notes_buf = alloc_elfnotes_buf(*notes_sz);
+ if (!*notes_buf)
+ return -ENOMEM;
+
+ rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
+ if (rc < 0)
+ return rc;
+
+ /* Prepare merged PT_NOTE program header. */
+ phdr.p_type = PT_NOTE;
+ phdr.p_flags = 0;
+ note_off = sizeof(Elf64_Ehdr) +
+ (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
+ phdr.p_offset = roundup(note_off, PAGE_SIZE);
+ phdr.p_vaddr = phdr.p_paddr = 0;
+ phdr.p_filesz = phdr.p_memsz = phdr_sz;
+ phdr.p_align = 0;
+
+ /* Add merged PT_NOTE program header*/
+ tmp = elfptr + sizeof(Elf64_Ehdr);
+ memcpy(tmp, &phdr, sizeof(phdr));
+ tmp += sizeof(phdr);
+
+ /* Remove unwanted PT_NOTE program headers. */
+ i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
+ *elfsz = *elfsz - i;
+ memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
+ memset(elfptr + *elfsz, 0, i);
+ *elfsz = roundup(*elfsz, PAGE_SIZE);
+
+ /* Modify e_phnum to reflect merged headers. */
+ ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
+
+ return 0;
+}
+
+/**
+ * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
+ *
+ * @ehdr_ptr: ELF header
+ *
+ * This function updates p_memsz member of each PT_NOTE entry in the
+ * program header table pointed to by @ehdr_ptr to real size of ELF
+ * note segment.
+ */
+static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
+{
+ int i, rc=0;
+ Elf32_Phdr *phdr_ptr;
+ Elf32_Nhdr *nhdr_ptr;
+
+ phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ void *notes_section;
+ u64 offset, max_sz, sz, real_sz = 0;
+ if (phdr_ptr->p_type != PT_NOTE)
+ continue;
+ max_sz = phdr_ptr->p_memsz;
+ offset = phdr_ptr->p_offset;
+ notes_section = kmalloc(max_sz, GFP_KERNEL);
+ if (!notes_section)
+ return -ENOMEM;
+ rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
+ if (rc < 0) {
+ kfree(notes_section);
+ return rc;
+ }
+ nhdr_ptr = notes_section;
+ while (nhdr_ptr->n_namesz != 0) {
+ sz = sizeof(Elf32_Nhdr) +
+ (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
+ (((u64)nhdr_ptr->n_descsz + 3) & ~3);
+ if ((real_sz + sz) > max_sz) {
+ pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
+ nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
+ break;
+ }
+ real_sz += sz;
+ nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
+ }
+ kfree(notes_section);
+ phdr_ptr->p_memsz = real_sz;
+ if (real_sz == 0) {
+ pr_warn("Warning: Zero PT_NOTE entries found\n");
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * get_note_number_and_size_elf32 - get the number of PT_NOTE program
+ * headers and sum of real size of their ELF note segment headers and
+ * data.
+ *
+ * @ehdr_ptr: ELF header
+ * @nr_ptnote: buffer for the number of PT_NOTE program headers
+ * @sz_ptnote: buffer for size of unique PT_NOTE program header
+ *
+ * This function is used to merge multiple PT_NOTE program headers
+ * into a unique single one. The resulting unique entry will have
+ * @sz_ptnote in its phdr->p_mem.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf32
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
+ int *nr_ptnote, u64 *sz_ptnote)
+{
+ int i;
+ Elf32_Phdr *phdr_ptr;
+
+ *nr_ptnote = *sz_ptnote = 0;
+
+ phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ if (phdr_ptr->p_type != PT_NOTE)
+ continue;
+ *nr_ptnote += 1;
+ *sz_ptnote += phdr_ptr->p_memsz;
+ }
+
+ return 0;
+}
+
+/**
+ * copy_notes_elf32 - copy ELF note segments in a given buffer
+ *
+ * @ehdr_ptr: ELF header
+ * @notes_buf: buffer into which ELF note segments are copied
+ *
+ * This function is used to copy ELF note segment in the 1st kernel
+ * into the buffer @notes_buf in the 2nd kernel. It is assumed that
+ * size of the buffer @notes_buf is equal to or larger than sum of the
+ * real ELF note segment headers and data.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf32
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
+{
+ int i, rc=0;
+ Elf32_Phdr *phdr_ptr;
+
+ phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
+
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ u64 offset;
+ if (phdr_ptr->p_type != PT_NOTE)
+ continue;
+ offset = phdr_ptr->p_offset;
+ rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
+ &offset);
+ if (rc < 0)
+ return rc;
+ notes_buf += phdr_ptr->p_memsz;
+ }
+
+ return 0;
+}
+
+/* Merges all the PT_NOTE headers into one. */
+static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
+ char **notes_buf, size_t *notes_sz)
+{
+ int i, nr_ptnote=0, rc=0;
+ char *tmp;
+ Elf32_Ehdr *ehdr_ptr;
+ Elf32_Phdr phdr;
+ u64 phdr_sz = 0, note_off;
+
+ ehdr_ptr = (Elf32_Ehdr *)elfptr;
+
+ rc = update_note_header_size_elf32(ehdr_ptr);
+ if (rc < 0)
+ return rc;
+
+ rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
+ if (rc < 0)
+ return rc;
+
+ *notes_sz = roundup(phdr_sz, PAGE_SIZE);
+ *notes_buf = alloc_elfnotes_buf(*notes_sz);
+ if (!*notes_buf)
+ return -ENOMEM;
+
+ rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
+ if (rc < 0)
+ return rc;
+
+ /* Prepare merged PT_NOTE program header. */
+ phdr.p_type = PT_NOTE;
+ phdr.p_flags = 0;
+ note_off = sizeof(Elf32_Ehdr) +
+ (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
+ phdr.p_offset = roundup(note_off, PAGE_SIZE);
+ phdr.p_vaddr = phdr.p_paddr = 0;
+ phdr.p_filesz = phdr.p_memsz = phdr_sz;
+ phdr.p_align = 0;
+
+ /* Add merged PT_NOTE program header*/
+ tmp = elfptr + sizeof(Elf32_Ehdr);
+ memcpy(tmp, &phdr, sizeof(phdr));
+ tmp += sizeof(phdr);
+
+ /* Remove unwanted PT_NOTE program headers. */
+ i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
+ *elfsz = *elfsz - i;
+ memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
+ memset(elfptr + *elfsz, 0, i);
+ *elfsz = roundup(*elfsz, PAGE_SIZE);
+
+ /* Modify e_phnum to reflect merged headers. */
+ ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
+
+ return 0;
+}
+
+/* Add memory chunks represented by program headers to vmcore list. Also update
+ * the new offset fields of exported program headers. */
+static int __init process_ptload_program_headers_elf64(char *elfptr,
+ size_t elfsz,
+ size_t elfnotes_sz,
+ struct list_head *vc_list)
+{
+ int i;
+ Elf64_Ehdr *ehdr_ptr;
+ Elf64_Phdr *phdr_ptr;
+ loff_t vmcore_off;
+ struct vmcore *new;
+
+ ehdr_ptr = (Elf64_Ehdr *)elfptr;
+ phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
+
+ /* Skip Elf header, program headers and Elf note segment. */
+ vmcore_off = elfsz + elfnotes_sz;
+
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ u64 paddr, start, end, size;
+
+ if (phdr_ptr->p_type != PT_LOAD)
+ continue;
+
+ paddr = phdr_ptr->p_offset;
+ start = rounddown(paddr, PAGE_SIZE);
+ end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
+ size = end - start;
+
+ /* Add this contiguous chunk of memory to vmcore list.*/
+ new = get_new_element();
+ if (!new)
+ return -ENOMEM;
+ new->paddr = start;
+ new->size = size;
+ list_add_tail(&new->list, vc_list);
+
+ /* Update the program header offset. */
+ phdr_ptr->p_offset = vmcore_off + (paddr - start);
+ vmcore_off = vmcore_off + size;
+ }
+ return 0;
+}
+
+static int __init process_ptload_program_headers_elf32(char *elfptr,
+ size_t elfsz,
+ size_t elfnotes_sz,
+ struct list_head *vc_list)
+{
+ int i;
+ Elf32_Ehdr *ehdr_ptr;
+ Elf32_Phdr *phdr_ptr;
+ loff_t vmcore_off;
+ struct vmcore *new;
+
+ ehdr_ptr = (Elf32_Ehdr *)elfptr;
+ phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
+
+ /* Skip Elf header, program headers and Elf note segment. */
+ vmcore_off = elfsz + elfnotes_sz;
+
+ for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+ u64 paddr, start, end, size;
+
+ if (phdr_ptr->p_type != PT_LOAD)
+ continue;
+
+ paddr = phdr_ptr->p_offset;
+ start = rounddown(paddr, PAGE_SIZE);
+ end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
+ size = end - start;
+
+ /* Add this contiguous chunk of memory to vmcore list.*/
+ new = get_new_element();
+ if (!new)
+ return -ENOMEM;
+ new->paddr = start;
+ new->size = size;
+ list_add_tail(&new->list, vc_list);
+
+ /* Update the program header offset */
+ phdr_ptr->p_offset = vmcore_off + (paddr - start);
+ vmcore_off = vmcore_off + size;
+ }
+ return 0;
+}
+
+/* Sets offset fields of vmcore elements. */
+static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
+ struct list_head *vc_list)
+{
+ loff_t vmcore_off;
+ struct vmcore *m;
+
+ /* Skip Elf header, program headers and Elf note segment. */
+ vmcore_off = elfsz + elfnotes_sz;
+
+ list_for_each_entry(m, vc_list, list) {
+ m->offset = vmcore_off;
+ vmcore_off += m->size;
+ }
+}
+
+static void free_elfcorebuf(void)
+{
+ free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
+ elfcorebuf = NULL;
+ vfree(elfnotes_buf);
+ elfnotes_buf = NULL;
+}
+
+static int __init parse_crash_elf64_headers(void)
+{
+ int rc=0;
+ Elf64_Ehdr ehdr;
+ u64 addr;
+
+ addr = elfcorehdr_addr;
+
+ /* Read Elf header */
+ rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
+ if (rc < 0)
+ return rc;
+
+ /* Do some basic Verification. */
+ if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
+ (ehdr.e_type != ET_CORE) ||
+ !vmcore_elf64_check_arch(&ehdr) ||
+ ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
+ ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
+ ehdr.e_version != EV_CURRENT ||
+ ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
+ ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
+ ehdr.e_phnum == 0) {
+ pr_warn("Warning: Core image elf header is not sane\n");
+ return -EINVAL;
+ }
+
+ /* Read in all elf headers. */
+ elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
+ ehdr.e_phnum * sizeof(Elf64_Phdr);
+ elfcorebuf_sz = elfcorebuf_sz_orig;
+ elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ get_order(elfcorebuf_sz_orig));
+ if (!elfcorebuf)
+ return -ENOMEM;
+ addr = elfcorehdr_addr;
+ rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
+ if (rc < 0)
+ goto fail;
+
+ /* Merge all PT_NOTE headers into one. */
+ rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
+ &elfnotes_buf, &elfnotes_sz);
+ if (rc)
+ goto fail;
+ rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
+ elfnotes_sz, &vmcore_list);
+ if (rc)
+ goto fail;
+ set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
+ return 0;
+fail:
+ free_elfcorebuf();
+ return rc;
+}
+
+static int __init parse_crash_elf32_headers(void)
+{
+ int rc=0;
+ Elf32_Ehdr ehdr;
+ u64 addr;
+
+ addr = elfcorehdr_addr;
+
+ /* Read Elf header */
+ rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
+ if (rc < 0)
+ return rc;
+
+ /* Do some basic Verification. */
+ if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
+ (ehdr.e_type != ET_CORE) ||
+ !elf_check_arch(&ehdr) ||
+ ehdr.e_ident[EI_CLASS] != ELFCLASS32||
+ ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
+ ehdr.e_version != EV_CURRENT ||
+ ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
+ ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
+ ehdr.e_phnum == 0) {
+ pr_warn("Warning: Core image elf header is not sane\n");
+ return -EINVAL;
+ }
+
+ /* Read in all elf headers. */
+ elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
+ elfcorebuf_sz = elfcorebuf_sz_orig;
+ elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ get_order(elfcorebuf_sz_orig));
+ if (!elfcorebuf)
+ return -ENOMEM;
+ addr = elfcorehdr_addr;
+ rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
+ if (rc < 0)
+ goto fail;
+
+ /* Merge all PT_NOTE headers into one. */
+ rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
+ &elfnotes_buf, &elfnotes_sz);
+ if (rc)
+ goto fail;
+ rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
+ elfnotes_sz, &vmcore_list);
+ if (rc)
+ goto fail;
+ set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
+ return 0;
+fail:
+ free_elfcorebuf();
+ return rc;
+}
+
+static int __init parse_crash_elf_headers(void)
+{
+ unsigned char e_ident[EI_NIDENT];
+ u64 addr;
+ int rc=0;
+
+ addr = elfcorehdr_addr;
+ rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
+ if (rc < 0)
+ return rc;
+ if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
+ pr_warn("Warning: Core image elf header not found\n");
+ return -EINVAL;
+ }
+
+ if (e_ident[EI_CLASS] == ELFCLASS64) {
+ rc = parse_crash_elf64_headers();
+ if (rc)
+ return rc;
+ } else if (e_ident[EI_CLASS] == ELFCLASS32) {
+ rc = parse_crash_elf32_headers();
+ if (rc)
+ return rc;
+ } else {
+ pr_warn("Warning: Core image elf header is not sane\n");
+ return -EINVAL;
+ }
+
+ /* Determine vmcore size. */
+ vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
+ &vmcore_list);
+
+ return 0;
+}
+
+/* Init function for vmcore module. */
+static int __init vmcore_init(void)
+{
+ int rc = 0;
+
+ /* Allow architectures to allocate ELF header in 2nd kernel */
+ rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
+ if (rc)
+ return rc;
+ /*
+ * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
+ * then capture the dump.
+ */
+ if (!(is_vmcore_usable()))
+ return rc;
+ rc = parse_crash_elf_headers();
+ if (rc) {
+ pr_warn("Kdump: vmcore not initialized\n");
+ return rc;
+ }
+ elfcorehdr_free(elfcorehdr_addr);
+ elfcorehdr_addr = ELFCORE_ADDR_ERR;
+
+ proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
+ if (proc_vmcore)
+ proc_vmcore->size = vmcore_size;
+ return 0;
+}
+fs_initcall(vmcore_init);
+
+/* Cleanup function for vmcore module. */
+void vmcore_cleanup(void)
+{
+ struct list_head *pos, *next;
+
+ if (proc_vmcore) {
+ proc_remove(proc_vmcore);
+ proc_vmcore = NULL;
+ }
+
+ /* clear the vmcore list. */
+ list_for_each_safe(pos, next, &vmcore_list) {
+ struct vmcore *m;
+
+ m = list_entry(pos, struct vmcore, list);
+ list_del(&m->list);
+ kfree(m);
+ }
+ free_elfcorebuf();
+}
Code Review / kvmfornfv.git / blobdiff