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- /*
- * 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();
- }
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