// SPDX-License-Identifier: GPL-2.0-only /* * 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 #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; /* Size of all notes minus the device dump notes */ static size_t elfnotes_orig_sz; /* Total size of vmcore file. */ static u64 vmcore_size; static struct proc_dir_entry *proc_vmcore; #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP /* Device Dump list and mutex to synchronize access to list */ static LIST_HEAD(vmcoredd_list); static DEFINE_MUTEX(vmcoredd_mutex); static bool vmcoredd_disabled; core_param(novmcoredd, vmcoredd_disabled, bool, 0); #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ /* Device Dump Size */ static size_t vmcoredd_orig_sz; static DEFINE_SPINLOCK(vmcore_cb_lock); DEFINE_STATIC_SRCU(vmcore_cb_srcu); /* List of registered vmcore callbacks. */ static LIST_HEAD(vmcore_cb_list); /* Whether the vmcore has been opened once. */ static bool vmcore_opened; void register_vmcore_cb(struct vmcore_cb *cb) { INIT_LIST_HEAD(&cb->next); spin_lock(&vmcore_cb_lock); list_add_tail(&cb->next, &vmcore_cb_list); /* * Registering a vmcore callback after the vmcore was opened is * very unusual (e.g., manual driver loading). */ if (vmcore_opened) pr_warn_once("Unexpected vmcore callback registration\n"); spin_unlock(&vmcore_cb_lock); } EXPORT_SYMBOL_GPL(register_vmcore_cb); void unregister_vmcore_cb(struct vmcore_cb *cb) { spin_lock(&vmcore_cb_lock); list_del_rcu(&cb->next); /* * Unregistering a vmcore callback after the vmcore was opened is * very unusual (e.g., forced driver removal), but we cannot stop * unregistering. */ if (vmcore_opened) pr_warn_once("Unexpected vmcore callback unregistration\n"); spin_unlock(&vmcore_cb_lock); synchronize_srcu(&vmcore_cb_srcu); } EXPORT_SYMBOL_GPL(unregister_vmcore_cb); static bool pfn_is_ram(unsigned long pfn) { struct vmcore_cb *cb; bool ret = true; list_for_each_entry_srcu(cb, &vmcore_cb_list, next, srcu_read_lock_held(&vmcore_cb_srcu)) { if (unlikely(!cb->pfn_is_ram)) continue; ret = cb->pfn_is_ram(cb, pfn); if (!ret) break; } return ret; } static int open_vmcore(struct inode *inode, struct file *file) { spin_lock(&vmcore_cb_lock); vmcore_opened = true; spin_unlock(&vmcore_cb_lock); return 0; } /* Reads a page from the oldmem device from given offset. */ ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, u64 *ppos, bool encrypted) { unsigned long pfn, offset; ssize_t nr_bytes; ssize_t read = 0, tmp; int idx; if (!count) return 0; offset = (unsigned long)(*ppos % PAGE_SIZE); pfn = (unsigned long)(*ppos / PAGE_SIZE); idx = srcu_read_lock(&vmcore_cb_srcu); 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)) { tmp = iov_iter_zero(nr_bytes, iter); } else { if (encrypted) tmp = copy_oldmem_page_encrypted(iter, pfn, nr_bytes, offset); else tmp = copy_oldmem_page(iter, pfn, nr_bytes, offset); } if (tmp < nr_bytes) { srcu_read_unlock(&vmcore_cb_srcu, idx); return -EFAULT; } *ppos += nr_bytes; count -= nr_bytes; read += nr_bytes; ++pfn; offset = 0; } while (count); srcu_read_unlock(&vmcore_cb_srcu, idx); 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) { struct kvec kvec = { .iov_base = buf, .iov_len = count }; struct iov_iter iter; iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count); return read_from_oldmem(&iter, count, ppos, false); } /* * Architectures may override this function to read from notes sections */ ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos) { struct kvec kvec = { .iov_base = buf, .iov_len = count }; struct iov_iter iter; iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count); return read_from_oldmem(&iter, count, ppos, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); } /* * 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) { prot = pgprot_encrypted(prot); return remap_pfn_range(vma, from, pfn, size, prot); } /* * Architectures which support memory encryption override this. */ ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn, size_t csize, unsigned long offset) { return copy_oldmem_page(iter, pfn, csize, offset); } #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size) { struct vmcoredd_node *dump; u64 offset = 0; int ret = 0; size_t tsz; char *buf; mutex_lock(&vmcoredd_mutex); list_for_each_entry(dump, &vmcoredd_list, list) { if (start < offset + dump->size) { tsz = min(offset + (u64)dump->size - start, (u64)size); buf = dump->buf + start - offset; if (copy_to_iter(buf, tsz, iter) < tsz) { ret = -EFAULT; goto out_unlock; } size -= tsz; start += tsz; /* Leave now if buffer filled already */ if (!size) goto out_unlock; } offset += dump->size; } out_unlock: mutex_unlock(&vmcoredd_mutex); return ret; } #ifdef CONFIG_MMU static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst, u64 start, size_t size) { struct vmcoredd_node *dump; u64 offset = 0; int ret = 0; size_t tsz; char *buf; mutex_lock(&vmcoredd_mutex); list_for_each_entry(dump, &vmcoredd_list, list) { if (start < offset + dump->size) { tsz = min(offset + (u64)dump->size - start, (u64)size); buf = dump->buf + start - offset; if (remap_vmalloc_range_partial(vma, dst, buf, 0, tsz)) { ret = -EFAULT; goto out_unlock; } size -= tsz; start += tsz; dst += tsz; /* Leave now if buffer filled already */ if (!size) goto out_unlock; } offset += dump->size; } out_unlock: mutex_unlock(&vmcoredd_mutex); return ret; } #endif /* CONFIG_MMU */ #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ /* 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(struct iov_iter *iter, loff_t *fpos) { ssize_t acc = 0, tmp; size_t tsz; u64 start; struct vmcore *m = NULL; if (!iov_iter_count(iter) || *fpos >= vmcore_size) return 0; iov_iter_truncate(iter, vmcore_size - *fpos); /* Read ELF core header */ if (*fpos < elfcorebuf_sz) { tsz = min(elfcorebuf_sz - (size_t)*fpos, iov_iter_count(iter)); if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz) return -EFAULT; *fpos += tsz; acc += tsz; /* leave now if filled buffer already */ if (!iov_iter_count(iter)) return acc; } /* Read ELF note segment */ if (*fpos < elfcorebuf_sz + elfnotes_sz) { void *kaddr; /* We add device dumps before other elf notes because the * other elf notes may not fill the elf notes buffer * completely and we will end up with zero-filled data * between the elf notes and the device dumps. Tools will * then try to decode this zero-filled data as valid notes * and we don't want that. Hence, adding device dumps before * the other elf notes ensure that zero-filled data can be * avoided. */ #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP /* Read device dumps */ if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) { tsz = min(elfcorebuf_sz + vmcoredd_orig_sz - (size_t)*fpos, iov_iter_count(iter)); start = *fpos - elfcorebuf_sz; if (vmcoredd_copy_dumps(iter, start, tsz)) return -EFAULT; *fpos += tsz; acc += tsz; /* leave now if filled buffer already */ if (!iov_iter_count(iter)) return acc; } #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ /* Read remaining elf notes */ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, iov_iter_count(iter)); kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz; if (copy_to_iter(kaddr, tsz, iter) < tsz) return -EFAULT; *fpos += tsz; acc += tsz; /* leave now if filled buffer already */ if (!iov_iter_count(iter)) 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, iov_iter_count(iter)); start = m->paddr + *fpos - m->offset; tmp = read_from_oldmem(iter, tsz, &start, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); if (tmp < 0) return tmp; *fpos += tsz; acc += tsz; /* leave now if filled buffer already */ if (!iov_iter_count(iter)) return acc; } } return acc; } static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter) { return __read_vmcore(iter, &iocb->ki_pos); } /* * The vmcore fault handler uses the page cache and fills data using the * standard __read_vmcore() function. * * On s390 the fault handler is used for memory regions that can't be mapped * directly with remap_pfn_range(). */ static vm_fault_t 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 iov_iter iter; struct kvec kvec; struct page *page; loff_t offset; 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; kvec.iov_base = page_address(page); kvec.iov_len = PAGE_SIZE; iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, PAGE_SIZE); rc = __read_vmcore(&iter, &offset); if (rc < 0) { unlock_page(page); put_page(page); return vmf_error(rc); } 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, }; /** * vmcore_alloc_buf - allocate buffer in vmalloc memory * @size: 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 *vmcore_alloc_buf(size_t size) { #ifdef CONFIG_MMU return vmalloc_user(size); #else return vzalloc(size); #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) { int ret, idx; /* * Check if a callback was registered to avoid looping over all * pages without a reason. */ idx = srcu_read_lock(&vmcore_cb_srcu); if (!list_empty(&vmcore_cb_list)) ret = remap_oldmem_pfn_checked(vma, from, pfn, size, prot); else ret = remap_oldmem_pfn_range(vma, from, pfn, size, prot); srcu_read_unlock(&vmcore_cb_srcu, idx); return ret; } 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; vm_flags_mod(vma, VM_MIXEDMAP, VM_MAYWRITE | VM_MAYEXEC); 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; /* We add device dumps before other elf notes because the * other elf notes may not fill the elf notes buffer * completely and we will end up with zero-filled data * between the elf notes and the device dumps. Tools will * then try to decode this zero-filled data as valid notes * and we don't want that. Hence, adding device dumps before * the other elf notes ensure that zero-filled data can be * avoided. This also ensures that the device dumps and * other elf notes can be properly mmaped at page aligned * address. */ #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP /* Read device dumps */ if (start < elfcorebuf_sz + vmcoredd_orig_sz) { u64 start_off; tsz = min(elfcorebuf_sz + vmcoredd_orig_sz - (size_t)start, size); start_off = start - elfcorebuf_sz; if (vmcoredd_mmap_dumps(vma, vma->vm_start + len, start_off, tsz)) goto fail; size -= tsz; start += tsz; len += tsz; /* leave now if filled buffer already */ if (!size) return 0; } #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ /* Read remaining elf notes */ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size); kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_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 proc_ops vmcore_proc_ops = { .proc_open = open_vmcore, .proc_read_iter = read_vmcore, .proc_lseek = default_llseek, .proc_mmap = mmap_vmcore, }; static struct vmcore* __init get_new_element(void) { return kzalloc(sizeof(struct vmcore), GFP_KERNEL); } static u64 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 = vmcore_alloc_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 = 4; /* 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; /* Store the size of all notes. We need this to update the note * header when the device dumps will be added. */ elfnotes_orig_sz = phdr.p_memsz; 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 = vmcore_alloc_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 = 4; /* 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; /* Store the size of all notes. We need this to update the note * header when the device dumps will be added. */ elfnotes_orig_sz = phdr.p_memsz; 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 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; } #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP /** * vmcoredd_write_header - Write vmcore device dump header at the * beginning of the dump's buffer. * @buf: Output buffer where the note is written * @data: Dump info * @size: Size of the dump * * Fills beginning of the dump's buffer with vmcore device dump header. */ static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data, u32 size) { struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf; vdd_hdr->n_namesz = sizeof(vdd_hdr->name); vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name); vdd_hdr->n_type = NT_VMCOREDD; strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME, sizeof(vdd_hdr->name)); memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name)); } /** * vmcoredd_update_program_headers - Update all ELF program headers * @elfptr: Pointer to elf header * @elfnotesz: Size of elf notes aligned to page size * @vmcoreddsz: Size of device dumps to be added to elf note header * * Determine type of ELF header (Elf64 or Elf32) and update the elf note size. * Also update the offsets of all the program headers after the elf note header. */ static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz, size_t vmcoreddsz) { unsigned char *e_ident = (unsigned char *)elfptr; u64 start, end, size; loff_t vmcore_off; u32 i; vmcore_off = elfcorebuf_sz + elfnotesz; if (e_ident[EI_CLASS] == ELFCLASS64) { Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr; Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr)); /* Update all program headers */ for (i = 0; i < ehdr->e_phnum; i++, phdr++) { if (phdr->p_type == PT_NOTE) { /* Update note size */ phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz; phdr->p_filesz = phdr->p_memsz; continue; } start = rounddown(phdr->p_offset, PAGE_SIZE); end = roundup(phdr->p_offset + phdr->p_memsz, PAGE_SIZE); size = end - start; phdr->p_offset = vmcore_off + (phdr->p_offset - start); vmcore_off += size; } } else { Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr; Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr)); /* Update all program headers */ for (i = 0; i < ehdr->e_phnum; i++, phdr++) { if (phdr->p_type == PT_NOTE) { /* Update note size */ phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz; phdr->p_filesz = phdr->p_memsz; continue; } start = rounddown(phdr->p_offset, PAGE_SIZE); end = roundup(phdr->p_offset + phdr->p_memsz, PAGE_SIZE); size = end - start; phdr->p_offset = vmcore_off + (phdr->p_offset - start); vmcore_off += size; } } } /** * vmcoredd_update_size - Update the total size of the device dumps and update * ELF header * @dump_size: Size of the current device dump to be added to total size * * Update the total size of all the device dumps and update the ELF program * headers. Calculate the new offsets for the vmcore list and update the * total vmcore size. */ static void vmcoredd_update_size(size_t dump_size) { vmcoredd_orig_sz += dump_size; elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz; vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz, vmcoredd_orig_sz); /* Update vmcore list offsets */ set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list); vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz, &vmcore_list); proc_vmcore->size = vmcore_size; } /** * vmcore_add_device_dump - Add a buffer containing device dump to vmcore * @data: dump info. * * Allocate a buffer and invoke the calling driver's dump collect routine. * Write ELF note at the beginning of the buffer to indicate vmcore device * dump and add the dump to global list. */ int vmcore_add_device_dump(struct vmcoredd_data *data) { struct vmcoredd_node *dump; void *buf = NULL; size_t data_size; int ret; if (vmcoredd_disabled) { pr_err_once("Device dump is disabled\n"); return -EINVAL; } if (!data || !strlen(data->dump_name) || !data->vmcoredd_callback || !data->size) return -EINVAL; dump = vzalloc(sizeof(*dump)); if (!dump) { ret = -ENOMEM; goto out_err; } /* Keep size of the buffer page aligned so that it can be mmaped */ data_size = roundup(sizeof(struct vmcoredd_header) + data->size, PAGE_SIZE); /* Allocate buffer for driver's to write their dumps */ buf = vmcore_alloc_buf(data_size); if (!buf) { ret = -ENOMEM; goto out_err; } vmcoredd_write_header(buf, data, data_size - sizeof(struct vmcoredd_header)); /* Invoke the driver's dump collection routing */ ret = data->vmcoredd_callback(data, buf + sizeof(struct vmcoredd_header)); if (ret) goto out_err; dump->buf = buf; dump->size = data_size; /* Add the dump to driver sysfs list */ mutex_lock(&vmcoredd_mutex); list_add_tail(&dump->list, &vmcoredd_list); mutex_unlock(&vmcoredd_mutex); vmcoredd_update_size(data_size); return 0; out_err: vfree(buf); vfree(dump); return ret; } EXPORT_SYMBOL(vmcore_add_device_dump); #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ /* Free all dumps in vmcore device dump list */ static void vmcore_free_device_dumps(void) { #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP mutex_lock(&vmcoredd_mutex); while (!list_empty(&vmcoredd_list)) { struct vmcoredd_node *dump; dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node, list); list_del(&dump->list); vfree(dump->buf); vfree(dump); } mutex_unlock(&vmcoredd_mutex); #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ } /* 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) { elfcorehdr_free(elfcorehdr_addr); 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, &vmcore_proc_ops); if (proc_vmcore) proc_vmcore->size = vmcore_size; return 0; } fs_initcall(vmcore_init); /* Cleanup function for vmcore module. */ void vmcore_cleanup(void) { if (proc_vmcore) { proc_remove(proc_vmcore); proc_vmcore = NULL; } /* clear the vmcore list. */ while (!list_empty(&vmcore_list)) { struct vmcore *m; m = list_first_entry(&vmcore_list, struct vmcore, list); list_del(&m->list); kfree(m); } free_elfcorebuf(); /* clear vmcore device dump list */ vmcore_free_device_dumps(); }