/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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); } /* * Architectures which support memory encryption override this. */ ssize_t __weak copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize, unsigned long offset, int userbuf) { return copy_oldmem_page(pfn, buf, csize, offset, userbuf); } /* * 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 = (size_t)min_t(unsigned long long, 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_fault *vmf) { #ifdef CONFIG_S390 struct address_space *mapping = vmf->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_SHIFT; buf = __va((page_to_pfn(page) << PAGE_SHIFT)); rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0); if (rc < 0) { unlock_page(page); put_page(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, NULL); 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, 0, 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 = (size_t)min_t(unsigned long long, 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, NULL); 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) || !vmcore_elf32_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(); }