From: "Vivek Goyal" <vgoyal@in.ibm.com> o Support for /proc/vmcore interface. This interface exports elf core image either in ELF32 or ELF64 format, depending on the format in which elf headers have been stored by crashed kernel. o Added support for CONFIG_VMCORE config option. o Removed the dependency on /proc/kcore. From: "Eric W. Biederman" <ebiederm@xmission.com> This patch has been refactored to more closely match the prevailing style in the affected files. And to clearly indicate the dependency between /proc/kcore and proc/vmcore.c From: Hariprasad Nellitheertha <hari@in.ibm.com> This patch contains the code that provides an ELF format interface to the previous kernel's memory post kexec reboot. Signed off by Hariprasad Nellitheertha <hari@in.ibm.com> Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>tirimbino
Vivek Goyal
20 years ago
committed by
Linus Torvalds
parent
2030eae52b
commit
666bfddbe8
@ -0,0 +1,451 @@ |
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/*
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* fs/proc/vmcore.c Interface for accessing the crash |
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* dump from the system's previous life. |
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* Heavily borrowed from fs/proc/kcore.c |
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* Created by: Hariprasad Nellitheertha (hari@in.ibm.com) |
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* Copyright (C) IBM Corporation, 2004. All rights reserved |
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* |
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*/ |
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#include <linux/config.h> |
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#include <linux/mm.h> |
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#include <linux/proc_fs.h> |
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#include <linux/user.h> |
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#include <linux/a.out.h> |
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#include <linux/elf.h> |
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#include <linux/elfcore.h> |
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#include <linux/proc_fs.h> |
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#include <linux/highmem.h> |
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#include <linux/bootmem.h> |
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#include <linux/init.h> |
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#include <linux/crash_dump.h> |
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#include <linux/list.h> |
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#include <asm/uaccess.h> |
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#include <asm/io.h> |
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/* List representing chunks of contiguous memory areas and their offsets in
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* vmcore file. |
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*/ |
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static LIST_HEAD(vmcore_list); |
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/* Stores the pointer to the buffer containing kernel elf core headers. */ |
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static char *elfcorebuf; |
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static size_t elfcorebuf_sz; |
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/* Total size of vmcore file. */ |
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static u64 vmcore_size; |
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struct proc_dir_entry *proc_vmcore = NULL; |
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/* Reads a page from the oldmem device from given offset. */ |
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static ssize_t read_from_oldmem(char *buf, size_t count, |
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loff_t *ppos, int userbuf) |
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{ |
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unsigned long pfn, offset; |
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size_t nr_bytes; |
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ssize_t read = 0, tmp; |
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if (!count) |
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return 0; |
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offset = (unsigned long)(*ppos % PAGE_SIZE); |
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pfn = (unsigned long)(*ppos / PAGE_SIZE); |
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if (pfn > saved_max_pfn) |
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return -EINVAL; |
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do { |
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if (count > (PAGE_SIZE - offset)) |
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nr_bytes = PAGE_SIZE - offset; |
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else |
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nr_bytes = count; |
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tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf); |
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if (tmp < 0) |
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return tmp; |
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*ppos += nr_bytes; |
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count -= nr_bytes; |
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buf += nr_bytes; |
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read += nr_bytes; |
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++pfn; |
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offset = 0; |
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} while (count); |
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return read; |
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} |
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/* Maps vmcore file offset to respective physical address in memroy. */ |
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static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list, |
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struct vmcore **m_ptr) |
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{ |
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struct vmcore *m; |
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u64 paddr; |
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list_for_each_entry(m, vc_list, list) { |
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u64 start, end; |
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start = m->offset; |
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end = m->offset + m->size - 1; |
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if (offset >= start && offset <= end) { |
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paddr = m->paddr + offset - start; |
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*m_ptr = m; |
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return paddr; |
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} |
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} |
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*m_ptr = NULL; |
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return 0; |
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} |
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/* Read from the ELF header and then the crash dump. On error, negative value is
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* returned otherwise number of bytes read are returned. |
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*/ |
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static ssize_t read_vmcore(struct file *file, char __user *buffer, |
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size_t buflen, loff_t *fpos) |
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{ |
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ssize_t acc = 0, tmp; |
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size_t tsz, nr_bytes; |
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u64 start; |
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struct vmcore *curr_m = NULL; |
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if (buflen == 0 || *fpos >= vmcore_size) |
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return 0; |
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/* trim buflen to not go beyond EOF */ |
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if (buflen > vmcore_size - *fpos) |
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buflen = vmcore_size - *fpos; |
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/* Read ELF core header */ |
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if (*fpos < elfcorebuf_sz) { |
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tsz = elfcorebuf_sz - *fpos; |
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if (buflen < tsz) |
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tsz = buflen; |
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if (copy_to_user(buffer, elfcorebuf + *fpos, tsz)) |
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return -EFAULT; |
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buflen -= tsz; |
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*fpos += tsz; |
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buffer += tsz; |
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acc += tsz; |
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/* leave now if filled buffer already */ |
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if (buflen == 0) |
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return acc; |
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} |
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start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m); |
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if (!curr_m) |
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return -EINVAL; |
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if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) |
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tsz = buflen; |
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/* Calculate left bytes in current memory segment. */ |
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nr_bytes = (curr_m->size - (start - curr_m->paddr)); |
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if (tsz > nr_bytes) |
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tsz = nr_bytes; |
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while (buflen) { |
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tmp = read_from_oldmem(buffer, tsz, &start, 1); |
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if (tmp < 0) |
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return tmp; |
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buflen -= tsz; |
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*fpos += tsz; |
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buffer += tsz; |
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acc += tsz; |
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if (start >= (curr_m->paddr + curr_m->size)) { |
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if (curr_m->list.next == &vmcore_list) |
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return acc; /*EOF*/ |
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curr_m = list_entry(curr_m->list.next, |
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struct vmcore, list); |
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start = curr_m->paddr; |
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} |
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if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) |
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tsz = buflen; |
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/* Calculate left bytes in current memory segment. */ |
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nr_bytes = (curr_m->size - (start - curr_m->paddr)); |
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if (tsz > nr_bytes) |
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tsz = nr_bytes; |
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} |
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return acc; |
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} |
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static int open_vmcore(struct inode *inode, struct file *filp) |
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{ |
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return 0; |
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} |
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struct file_operations proc_vmcore_operations = { |
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.read = read_vmcore, |
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.open = open_vmcore, |
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}; |
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static struct vmcore* __init get_new_element(void) |
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{ |
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struct vmcore *p; |
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p = kmalloc(sizeof(*p), GFP_KERNEL); |
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if (p) |
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memset(p, 0, sizeof(*p)); |
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return p; |
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} |
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static u64 __init get_vmcore_size_elf64(char *elfptr) |
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{ |
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int i; |
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u64 size; |
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Elf64_Ehdr *ehdr_ptr; |
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Elf64_Phdr *phdr_ptr; |
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ehdr_ptr = (Elf64_Ehdr *)elfptr; |
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phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); |
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size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr)); |
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for (i = 0; i < ehdr_ptr->e_phnum; i++) { |
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size += phdr_ptr->p_memsz; |
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phdr_ptr++; |
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} |
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return size; |
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} |
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/* Merges all the PT_NOTE headers into one. */ |
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static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz, |
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struct list_head *vc_list) |
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{ |
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int i, nr_ptnote=0, rc=0; |
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char *tmp; |
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Elf64_Ehdr *ehdr_ptr; |
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Elf64_Phdr phdr, *phdr_ptr; |
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Elf64_Nhdr *nhdr_ptr; |
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u64 phdr_sz = 0, note_off; |
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ehdr_ptr = (Elf64_Ehdr *)elfptr; |
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phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); |
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for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { |
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int j; |
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void *notes_section; |
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struct vmcore *new; |
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u64 offset, max_sz, sz, real_sz = 0; |
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if (phdr_ptr->p_type != PT_NOTE) |
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continue; |
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nr_ptnote++; |
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max_sz = phdr_ptr->p_memsz; |
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offset = phdr_ptr->p_offset; |
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notes_section = kmalloc(max_sz, GFP_KERNEL); |
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if (!notes_section) |
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return -ENOMEM; |
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rc = read_from_oldmem(notes_section, max_sz, &offset, 0); |
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if (rc < 0) { |
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kfree(notes_section); |
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return rc; |
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} |
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nhdr_ptr = notes_section; |
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for (j = 0; j < max_sz; j += sz) { |
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if (nhdr_ptr->n_namesz == 0) |
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break; |
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sz = sizeof(Elf64_Nhdr) + |
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((nhdr_ptr->n_namesz + 3) & ~3) + |
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((nhdr_ptr->n_descsz + 3) & ~3); |
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real_sz += sz; |
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nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz); |
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} |
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/* Add this contiguous chunk of notes section to vmcore list.*/ |
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new = get_new_element(); |
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if (!new) { |
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kfree(notes_section); |
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return -ENOMEM; |
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} |
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new->paddr = phdr_ptr->p_offset; |
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new->size = real_sz; |
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list_add_tail(&new->list, vc_list); |
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phdr_sz += real_sz; |
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kfree(notes_section); |
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} |
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/* Prepare merged PT_NOTE program header. */ |
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phdr.p_type = PT_NOTE; |
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phdr.p_flags = 0; |
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note_off = sizeof(Elf64_Ehdr) + |
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(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr); |
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phdr.p_offset = note_off; |
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phdr.p_vaddr = phdr.p_paddr = 0; |
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phdr.p_filesz = phdr.p_memsz = phdr_sz; |
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phdr.p_align = 0; |
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/* Add merged PT_NOTE program header*/ |
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tmp = elfptr + sizeof(Elf64_Ehdr); |
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memcpy(tmp, &phdr, sizeof(phdr)); |
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tmp += sizeof(phdr); |
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/* Remove unwanted PT_NOTE program headers. */ |
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i = (nr_ptnote - 1) * sizeof(Elf64_Phdr); |
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*elfsz = *elfsz - i; |
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memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr))); |
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/* Modify e_phnum to reflect merged headers. */ |
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ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1; |
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return 0; |
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} |
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/* Add memory chunks represented by program headers to vmcore list. Also update
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* the new offset fields of exported program headers. */ |
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static int __init process_ptload_program_headers_elf64(char *elfptr, |
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size_t elfsz, |
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struct list_head *vc_list) |
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{ |
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int i; |
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Elf64_Ehdr *ehdr_ptr; |
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Elf64_Phdr *phdr_ptr; |
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loff_t vmcore_off; |
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struct vmcore *new; |
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ehdr_ptr = (Elf64_Ehdr *)elfptr; |
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phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */ |
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/* First program header is PT_NOTE header. */ |
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vmcore_off = sizeof(Elf64_Ehdr) + |
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(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) + |
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phdr_ptr->p_memsz; /* Note sections */ |
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for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { |
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if (phdr_ptr->p_type != PT_LOAD) |
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continue; |
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/* Add this contiguous chunk of memory to vmcore list.*/ |
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new = get_new_element(); |
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if (!new) |
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return -ENOMEM; |
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new->paddr = phdr_ptr->p_offset; |
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new->size = phdr_ptr->p_memsz; |
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list_add_tail(&new->list, vc_list); |
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/* Update the program header offset. */ |
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phdr_ptr->p_offset = vmcore_off; |
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vmcore_off = vmcore_off + phdr_ptr->p_memsz; |
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} |
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return 0; |
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} |
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/* Sets offset fields of vmcore elements. */ |
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static void __init set_vmcore_list_offsets_elf64(char *elfptr, |
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struct list_head *vc_list) |
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{ |
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loff_t vmcore_off; |
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Elf64_Ehdr *ehdr_ptr; |
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struct vmcore *m; |
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ehdr_ptr = (Elf64_Ehdr *)elfptr; |
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/* Skip Elf header and program headers. */ |
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vmcore_off = sizeof(Elf64_Ehdr) + |
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(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr); |
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list_for_each_entry(m, vc_list, list) { |
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m->offset = vmcore_off; |
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vmcore_off += m->size; |
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} |
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} |
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static int __init parse_crash_elf64_headers(void) |
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{ |
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int rc=0; |
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Elf64_Ehdr ehdr; |
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u64 addr; |
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addr = elfcorehdr_addr; |
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/* Read Elf header */ |
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rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0); |
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if (rc < 0) |
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return rc; |
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/* Do some basic Verification. */ |
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if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 || |
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(ehdr.e_type != ET_CORE) || |
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!elf_check_arch(&ehdr) || |
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ehdr.e_ident[EI_CLASS] != ELFCLASS64 || |
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ehdr.e_ident[EI_VERSION] != EV_CURRENT || |
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ehdr.e_version != EV_CURRENT || |
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ehdr.e_ehsize != sizeof(Elf64_Ehdr) || |
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ehdr.e_phentsize != sizeof(Elf64_Phdr) || |
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ehdr.e_phnum == 0) { |
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printk(KERN_WARNING "Warning: Core image elf header is not" |
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"sane\n"); |
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return -EINVAL; |
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} |
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/* Read in all elf headers. */ |
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elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr); |
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elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL); |
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if (!elfcorebuf) |
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return -ENOMEM; |
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addr = elfcorehdr_addr; |
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rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0); |
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if (rc < 0) { |
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kfree(elfcorebuf); |
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return rc; |
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} |
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/* Merge all PT_NOTE headers into one. */ |
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rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list); |
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if (rc) { |
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kfree(elfcorebuf); |
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return rc; |
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} |
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rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz, |
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&vmcore_list); |
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if (rc) { |
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kfree(elfcorebuf); |
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return rc; |
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} |
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set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list); |
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return 0; |
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} |
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static int __init parse_crash_elf_headers(void) |
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{ |
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unsigned char e_ident[EI_NIDENT]; |
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u64 addr; |
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int rc=0; |
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addr = elfcorehdr_addr; |
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rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0); |
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if (rc < 0) |
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return rc; |
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if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) { |
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printk(KERN_WARNING "Warning: Core image elf header" |
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" not found\n"); |
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return -EINVAL; |
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} |
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if (e_ident[EI_CLASS] == ELFCLASS64) { |
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rc = parse_crash_elf64_headers(); |
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if (rc) |
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return rc; |
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/* Determine vmcore size. */ |
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vmcore_size = get_vmcore_size_elf64(elfcorebuf); |
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} else { |
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printk(KERN_WARNING "Warning: Core image elf header is not" |
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" sane\n"); |
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return -EINVAL; |
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} |
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return 0; |
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} |
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/* Init function for vmcore module. */ |
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static int __init vmcore_init(void) |
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{ |
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int rc = 0; |
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/* If elfcorehdr= has been passed in cmdline, then capture the dump.*/ |
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if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX)) |
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return rc; |
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rc = parse_crash_elf_headers(); |
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if (rc) { |
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printk(KERN_WARNING "Kdump: vmcore not initialized\n"); |
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return rc; |
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} |
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/* Initialize /proc/vmcore size if proc is already up. */ |
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if (proc_vmcore) |
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proc_vmcore->size = vmcore_size; |
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return 0; |
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} |
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module_init(vmcore_init) |
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Reference in new issue