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![Vitaly Kuznetsov](/assets/img/avatar_default.png)
We have a special check in read_vmcore() handler to check if the page was reported as ram or not by the hypervisor (pfn_is_ram()). However, when vmcore is read with mmap() no such check is performed. That can lead to unpredictable results, e.g. when running Xen PVHVM guest memcpy() after mmap() on /proc/vmcore will hang processing HVMMEM_mmio_dm pages creating enormous load in both DomU and Dom0. Fix the issue by mapping each non-ram page to the zero page. Keep direct path with remap_oldmem_pfn_range() to avoid looping through all pages on bare metal. The issue can also be solved by overriding remap_oldmem_pfn_range() in xen-specific code, as remap_oldmem_pfn_range() was been designed for. That, however, would involve non-obvious xen code path for all x86 builds with CONFIG_XEN_PVHVM=y and would prevent all other hypervisor-specific code on x86 arch from doing the same override. [fengguang.wu@intel.com: remap_oldmem_pfn_checked() can be static] [akpm@linux-foundation.org: clean up layout] Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1194 lines
30 KiB
C
1194 lines
30 KiB
C
/*
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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/mm.h>
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#include <linux/kcore.h>
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#include <linux/user.h>
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#include <linux/elf.h>
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#include <linux/elfcore.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/highmem.h>
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#include <linux/printk.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 <linux/vmalloc.h>
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#include <linux/pagemap.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include "internal.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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static size_t elfcorebuf_sz_orig;
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static char *elfnotes_buf;
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static size_t elfnotes_sz;
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/* Total size of vmcore file. */
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static u64 vmcore_size;
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static struct proc_dir_entry *proc_vmcore;
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/*
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* Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
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* The called function has to take care of module refcounting.
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*/
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static int (*oldmem_pfn_is_ram)(unsigned long pfn);
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int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
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{
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if (oldmem_pfn_is_ram)
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return -EBUSY;
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oldmem_pfn_is_ram = fn;
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return 0;
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}
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EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
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void unregister_oldmem_pfn_is_ram(void)
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{
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oldmem_pfn_is_ram = NULL;
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wmb();
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}
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EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
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static int pfn_is_ram(unsigned long pfn)
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{
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int (*fn)(unsigned long pfn);
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/* pfn is ram unless fn() checks pagetype */
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int ret = 1;
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/*
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* Ask hypervisor if the pfn is really ram.
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* A ballooned page contains no data and reading from such a page
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* will cause high load in the hypervisor.
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*/
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fn = oldmem_pfn_is_ram;
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if (fn)
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ret = fn(pfn);
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return ret;
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}
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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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u64 *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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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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/* If pfn is not ram, return zeros for sparse dump files */
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if (pfn_is_ram(pfn) == 0)
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memset(buf, 0, nr_bytes);
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else {
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tmp = copy_oldmem_page(pfn, buf, nr_bytes,
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offset, userbuf);
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if (tmp < 0)
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return tmp;
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}
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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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/*
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* Architectures may override this function to allocate ELF header in 2nd kernel
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*/
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int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
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{
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return 0;
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}
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/*
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* Architectures may override this function to free header
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*/
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void __weak elfcorehdr_free(unsigned long long addr)
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{}
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/*
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* Architectures may override this function to read from ELF header
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*/
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ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
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{
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return read_from_oldmem(buf, count, ppos, 0);
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}
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/*
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* Architectures may override this function to read from notes sections
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*/
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ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
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{
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return read_from_oldmem(buf, count, ppos, 0);
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}
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/*
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* Architectures may override this function to map oldmem
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*/
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int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
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unsigned long from, unsigned long pfn,
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unsigned long size, pgprot_t prot)
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{
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return remap_pfn_range(vma, from, pfn, size, prot);
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}
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/*
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* Copy to either kernel or user space
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*/
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static int copy_to(void *target, void *src, size_t size, int userbuf)
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{
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if (userbuf) {
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if (copy_to_user((char __user *) target, src, size))
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return -EFAULT;
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} else {
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memcpy(target, src, size);
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}
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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(char *buffer, size_t buflen, loff_t *fpos,
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int userbuf)
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{
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ssize_t acc = 0, tmp;
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size_t tsz;
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u64 start;
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struct vmcore *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 = min(elfcorebuf_sz - (size_t)*fpos, buflen);
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if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
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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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/* Read Elf note segment */
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if (*fpos < elfcorebuf_sz + elfnotes_sz) {
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void *kaddr;
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tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
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kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
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if (copy_to(buffer, kaddr, tsz, userbuf))
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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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list_for_each_entry(m, &vmcore_list, list) {
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if (*fpos < m->offset + m->size) {
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tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
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start = m->paddr + *fpos - m->offset;
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tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
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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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/* 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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}
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return acc;
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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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return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
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}
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/*
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* The vmcore fault handler uses the page cache and fills data using the
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* standard __vmcore_read() function.
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*
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* On s390 the fault handler is used for memory regions that can't be mapped
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* directly with remap_pfn_range().
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*/
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static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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#ifdef CONFIG_S390
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struct address_space *mapping = vma->vm_file->f_mapping;
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pgoff_t index = vmf->pgoff;
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struct page *page;
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loff_t offset;
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char *buf;
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int rc;
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page = find_or_create_page(mapping, index, GFP_KERNEL);
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if (!page)
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return VM_FAULT_OOM;
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if (!PageUptodate(page)) {
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offset = (loff_t) index << PAGE_CACHE_SHIFT;
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buf = __va((page_to_pfn(page) << PAGE_SHIFT));
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rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
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if (rc < 0) {
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unlock_page(page);
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page_cache_release(page);
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return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
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}
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SetPageUptodate(page);
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}
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unlock_page(page);
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vmf->page = page;
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return 0;
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#else
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return VM_FAULT_SIGBUS;
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#endif
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}
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static const struct vm_operations_struct vmcore_mmap_ops = {
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.fault = mmap_vmcore_fault,
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};
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/**
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* alloc_elfnotes_buf - allocate buffer for ELF note segment in
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* vmalloc memory
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*
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* @notes_sz: size of buffer
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*
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* If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
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* the buffer to user-space by means of remap_vmalloc_range().
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*
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* If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
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* disabled and there's no need to allow users to mmap the buffer.
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*/
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static inline char *alloc_elfnotes_buf(size_t notes_sz)
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{
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#ifdef CONFIG_MMU
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return vmalloc_user(notes_sz);
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#else
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return vzalloc(notes_sz);
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#endif
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}
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/*
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* Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
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* essential for mmap_vmcore() in order to map physically
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* non-contiguous objects (ELF header, ELF note segment and memory
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* regions in the 1st kernel pointed to by PT_LOAD entries) into
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* virtually contiguous user-space in ELF layout.
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*/
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#ifdef CONFIG_MMU
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/*
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* remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
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* reported as not being ram with the zero page.
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*
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* @vma: vm_area_struct describing requested mapping
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* @from: start remapping from
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* @pfn: page frame number to start remapping to
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* @size: remapping size
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* @prot: protection bits
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*
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* Returns zero on success, -EAGAIN on failure.
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*/
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static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
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unsigned long from, unsigned long pfn,
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unsigned long size, pgprot_t prot)
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{
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unsigned long map_size;
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unsigned long pos_start, pos_end, pos;
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unsigned long zeropage_pfn = my_zero_pfn(0);
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size_t len = 0;
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pos_start = pfn;
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pos_end = pfn + (size >> PAGE_SHIFT);
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for (pos = pos_start; pos < pos_end; ++pos) {
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if (!pfn_is_ram(pos)) {
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/*
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* We hit a page which is not ram. Remap the continuous
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* region between pos_start and pos-1 and replace
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* the non-ram page at pos with the zero page.
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*/
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if (pos > pos_start) {
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/* Remap continuous region */
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map_size = (pos - pos_start) << PAGE_SHIFT;
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if (remap_oldmem_pfn_range(vma, from + len,
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pos_start, map_size,
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prot))
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goto fail;
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len += map_size;
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}
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/* Remap the zero page */
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if (remap_oldmem_pfn_range(vma, from + len,
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zeropage_pfn,
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PAGE_SIZE, prot))
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goto fail;
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len += PAGE_SIZE;
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pos_start = pos + 1;
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}
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}
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if (pos > pos_start) {
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/* Remap the rest */
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map_size = (pos - pos_start) << PAGE_SHIFT;
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if (remap_oldmem_pfn_range(vma, from + len, pos_start,
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map_size, prot))
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goto fail;
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}
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return 0;
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fail:
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do_munmap(vma->vm_mm, from, len);
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return -EAGAIN;
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}
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|
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static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
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unsigned long from, unsigned long pfn,
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unsigned long size, pgprot_t prot)
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{
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/*
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* Check if oldmem_pfn_is_ram was registered to avoid
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* looping over all pages without a reason.
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*/
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if (oldmem_pfn_is_ram)
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return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
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else
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return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
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}
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|
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static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
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{
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size_t size = vma->vm_end - vma->vm_start;
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u64 start, end, len, tsz;
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struct vmcore *m;
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|
|
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start = (u64)vma->vm_pgoff << PAGE_SHIFT;
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end = start + size;
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if (size > vmcore_size || end > vmcore_size)
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return -EINVAL;
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|
|
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if (vma->vm_flags & (VM_WRITE | VM_EXEC))
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return -EPERM;
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|
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vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
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vma->vm_flags |= VM_MIXEDMAP;
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vma->vm_ops = &vmcore_mmap_ops;
|
|
|
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len = 0;
|
|
|
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if (start < elfcorebuf_sz) {
|
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u64 pfn;
|
|
|
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tsz = min(elfcorebuf_sz - (size_t)start, size);
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pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
|
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if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
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vma->vm_page_prot))
|
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return -EAGAIN;
|
|
size -= tsz;
|
|
start += tsz;
|
|
len += tsz;
|
|
|
|
if (size == 0)
|
|
return 0;
|
|
}
|
|
|
|
if (start < elfcorebuf_sz + elfnotes_sz) {
|
|
void *kaddr;
|
|
|
|
tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
|
|
kaddr = elfnotes_buf + start - elfcorebuf_sz;
|
|
if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
|
|
kaddr, tsz))
|
|
goto fail;
|
|
size -= tsz;
|
|
start += tsz;
|
|
len += tsz;
|
|
|
|
if (size == 0)
|
|
return 0;
|
|
}
|
|
|
|
list_for_each_entry(m, &vmcore_list, list) {
|
|
if (start < m->offset + m->size) {
|
|
u64 paddr = 0;
|
|
|
|
tsz = min_t(size_t, m->offset + m->size - start, size);
|
|
paddr = m->paddr + start - m->offset;
|
|
if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
|
|
paddr >> PAGE_SHIFT, tsz,
|
|
vma->vm_page_prot))
|
|
goto fail;
|
|
size -= tsz;
|
|
start += tsz;
|
|
len += tsz;
|
|
|
|
if (size == 0)
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
fail:
|
|
do_munmap(vma->vm_mm, vma->vm_start, len);
|
|
return -EAGAIN;
|
|
}
|
|
#else
|
|
static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
#endif
|
|
|
|
static const struct file_operations proc_vmcore_operations = {
|
|
.read = read_vmcore,
|
|
.llseek = default_llseek,
|
|
.mmap = mmap_vmcore,
|
|
};
|
|
|
|
static struct vmcore* __init get_new_element(void)
|
|
{
|
|
return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
|
|
}
|
|
|
|
static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
|
|
struct list_head *vc_list)
|
|
{
|
|
u64 size;
|
|
struct vmcore *m;
|
|
|
|
size = elfsz + elfnotesegsz;
|
|
list_for_each_entry(m, vc_list, list) {
|
|
size += m->size;
|
|
}
|
|
return size;
|
|
}
|
|
|
|
/**
|
|
* update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
|
|
*
|
|
* @ehdr_ptr: ELF header
|
|
*
|
|
* This function updates p_memsz member of each PT_NOTE entry in the
|
|
* program header table pointed to by @ehdr_ptr to real size of ELF
|
|
* note segment.
|
|
*/
|
|
static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
|
|
{
|
|
int i, rc=0;
|
|
Elf64_Phdr *phdr_ptr;
|
|
Elf64_Nhdr *nhdr_ptr;
|
|
|
|
phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
|
|
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
|
|
void *notes_section;
|
|
u64 offset, max_sz, sz, real_sz = 0;
|
|
if (phdr_ptr->p_type != PT_NOTE)
|
|
continue;
|
|
max_sz = phdr_ptr->p_memsz;
|
|
offset = phdr_ptr->p_offset;
|
|
notes_section = kmalloc(max_sz, GFP_KERNEL);
|
|
if (!notes_section)
|
|
return -ENOMEM;
|
|
rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
|
|
if (rc < 0) {
|
|
kfree(notes_section);
|
|
return rc;
|
|
}
|
|
nhdr_ptr = notes_section;
|
|
while (nhdr_ptr->n_namesz != 0) {
|
|
sz = sizeof(Elf64_Nhdr) +
|
|
((nhdr_ptr->n_namesz + 3) & ~3) +
|
|
((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) +
|
|
((nhdr_ptr->n_namesz + 3) & ~3) +
|
|
((nhdr_ptr->n_descsz + 3) & ~3);
|
|
if ((real_sz + sz) > max_sz) {
|
|
pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
|
|
nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
|
|
break;
|
|
}
|
|
real_sz += sz;
|
|
nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
|
|
}
|
|
kfree(notes_section);
|
|
phdr_ptr->p_memsz = real_sz;
|
|
if (real_sz == 0) {
|
|
pr_warn("Warning: Zero PT_NOTE entries found\n");
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* get_note_number_and_size_elf32 - get the number of PT_NOTE program
|
|
* headers and sum of real size of their ELF note segment headers and
|
|
* data.
|
|
*
|
|
* @ehdr_ptr: ELF header
|
|
* @nr_ptnote: buffer for the number of PT_NOTE program headers
|
|
* @sz_ptnote: buffer for size of unique PT_NOTE program header
|
|
*
|
|
* This function is used to merge multiple PT_NOTE program headers
|
|
* into a unique single one. The resulting unique entry will have
|
|
* @sz_ptnote in its phdr->p_mem.
|
|
*
|
|
* It is assumed that program headers with PT_NOTE type pointed to by
|
|
* @ehdr_ptr has already been updated by update_note_header_size_elf32
|
|
* and each of PT_NOTE program headers has actual ELF note segment
|
|
* size in its p_memsz member.
|
|
*/
|
|
static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
|
|
int *nr_ptnote, u64 *sz_ptnote)
|
|
{
|
|
int i;
|
|
Elf32_Phdr *phdr_ptr;
|
|
|
|
*nr_ptnote = *sz_ptnote = 0;
|
|
|
|
phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
|
|
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
|
|
if (phdr_ptr->p_type != PT_NOTE)
|
|
continue;
|
|
*nr_ptnote += 1;
|
|
*sz_ptnote += phdr_ptr->p_memsz;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* copy_notes_elf32 - copy ELF note segments in a given buffer
|
|
*
|
|
* @ehdr_ptr: ELF header
|
|
* @notes_buf: buffer into which ELF note segments are copied
|
|
*
|
|
* This function is used to copy ELF note segment in the 1st kernel
|
|
* into the buffer @notes_buf in the 2nd kernel. It is assumed that
|
|
* size of the buffer @notes_buf is equal to or larger than sum of the
|
|
* real ELF note segment headers and data.
|
|
*
|
|
* It is assumed that program headers with PT_NOTE type pointed to by
|
|
* @ehdr_ptr has already been updated by update_note_header_size_elf32
|
|
* and each of PT_NOTE program headers has actual ELF note segment
|
|
* size in its p_memsz member.
|
|
*/
|
|
static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
|
|
{
|
|
int i, rc=0;
|
|
Elf32_Phdr *phdr_ptr;
|
|
|
|
phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
|
|
|
|
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
|
|
u64 offset;
|
|
if (phdr_ptr->p_type != PT_NOTE)
|
|
continue;
|
|
offset = phdr_ptr->p_offset;
|
|
rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
|
|
&offset);
|
|
if (rc < 0)
|
|
return rc;
|
|
notes_buf += phdr_ptr->p_memsz;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Merges all the PT_NOTE headers into one. */
|
|
static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
|
|
char **notes_buf, size_t *notes_sz)
|
|
{
|
|
int i, nr_ptnote=0, rc=0;
|
|
char *tmp;
|
|
Elf32_Ehdr *ehdr_ptr;
|
|
Elf32_Phdr phdr;
|
|
u64 phdr_sz = 0, note_off;
|
|
|
|
ehdr_ptr = (Elf32_Ehdr *)elfptr;
|
|
|
|
rc = update_note_header_size_elf32(ehdr_ptr);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
*notes_sz = roundup(phdr_sz, PAGE_SIZE);
|
|
*notes_buf = alloc_elfnotes_buf(*notes_sz);
|
|
if (!*notes_buf)
|
|
return -ENOMEM;
|
|
|
|
rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
/* Prepare merged PT_NOTE program header. */
|
|
phdr.p_type = PT_NOTE;
|
|
phdr.p_flags = 0;
|
|
note_off = sizeof(Elf32_Ehdr) +
|
|
(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
|
|
phdr.p_offset = roundup(note_off, PAGE_SIZE);
|
|
phdr.p_vaddr = phdr.p_paddr = 0;
|
|
phdr.p_filesz = phdr.p_memsz = phdr_sz;
|
|
phdr.p_align = 0;
|
|
|
|
/* Add merged PT_NOTE program header*/
|
|
tmp = elfptr + sizeof(Elf32_Ehdr);
|
|
memcpy(tmp, &phdr, sizeof(phdr));
|
|
tmp += sizeof(phdr);
|
|
|
|
/* Remove unwanted PT_NOTE program headers. */
|
|
i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
|
|
*elfsz = *elfsz - i;
|
|
memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
|
|
memset(elfptr + *elfsz, 0, i);
|
|
*elfsz = roundup(*elfsz, PAGE_SIZE);
|
|
|
|
/* Modify e_phnum to reflect merged headers. */
|
|
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Add memory chunks represented by program headers to vmcore list. Also update
|
|
* the new offset fields of exported program headers. */
|
|
static int __init process_ptload_program_headers_elf64(char *elfptr,
|
|
size_t elfsz,
|
|
size_t elfnotes_sz,
|
|
struct list_head *vc_list)
|
|
{
|
|
int i;
|
|
Elf64_Ehdr *ehdr_ptr;
|
|
Elf64_Phdr *phdr_ptr;
|
|
loff_t vmcore_off;
|
|
struct vmcore *new;
|
|
|
|
ehdr_ptr = (Elf64_Ehdr *)elfptr;
|
|
phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
|
|
|
|
/* Skip Elf header, program headers and Elf note segment. */
|
|
vmcore_off = elfsz + elfnotes_sz;
|
|
|
|
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
|
|
u64 paddr, start, end, size;
|
|
|
|
if (phdr_ptr->p_type != PT_LOAD)
|
|
continue;
|
|
|
|
paddr = phdr_ptr->p_offset;
|
|
start = rounddown(paddr, PAGE_SIZE);
|
|
end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
|
|
size = end - start;
|
|
|
|
/* Add this contiguous chunk of memory to vmcore list.*/
|
|
new = get_new_element();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
new->paddr = start;
|
|
new->size = size;
|
|
list_add_tail(&new->list, vc_list);
|
|
|
|
/* Update the program header offset. */
|
|
phdr_ptr->p_offset = vmcore_off + (paddr - start);
|
|
vmcore_off = vmcore_off + size;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __init process_ptload_program_headers_elf32(char *elfptr,
|
|
size_t elfsz,
|
|
size_t elfnotes_sz,
|
|
struct list_head *vc_list)
|
|
{
|
|
int i;
|
|
Elf32_Ehdr *ehdr_ptr;
|
|
Elf32_Phdr *phdr_ptr;
|
|
loff_t vmcore_off;
|
|
struct vmcore *new;
|
|
|
|
ehdr_ptr = (Elf32_Ehdr *)elfptr;
|
|
phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
|
|
|
|
/* Skip Elf header, program headers and Elf note segment. */
|
|
vmcore_off = elfsz + elfnotes_sz;
|
|
|
|
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
|
|
u64 paddr, start, end, size;
|
|
|
|
if (phdr_ptr->p_type != PT_LOAD)
|
|
continue;
|
|
|
|
paddr = phdr_ptr->p_offset;
|
|
start = rounddown(paddr, PAGE_SIZE);
|
|
end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
|
|
size = end - start;
|
|
|
|
/* Add this contiguous chunk of memory to vmcore list.*/
|
|
new = get_new_element();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
new->paddr = start;
|
|
new->size = size;
|
|
list_add_tail(&new->list, vc_list);
|
|
|
|
/* Update the program header offset */
|
|
phdr_ptr->p_offset = vmcore_off + (paddr - start);
|
|
vmcore_off = vmcore_off + size;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Sets offset fields of vmcore elements. */
|
|
static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
|
|
struct list_head *vc_list)
|
|
{
|
|
loff_t vmcore_off;
|
|
struct vmcore *m;
|
|
|
|
/* Skip Elf header, program headers and Elf note segment. */
|
|
vmcore_off = elfsz + elfnotes_sz;
|
|
|
|
list_for_each_entry(m, vc_list, list) {
|
|
m->offset = vmcore_off;
|
|
vmcore_off += m->size;
|
|
}
|
|
}
|
|
|
|
static void free_elfcorebuf(void)
|
|
{
|
|
free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
|
|
elfcorebuf = NULL;
|
|
vfree(elfnotes_buf);
|
|
elfnotes_buf = NULL;
|
|
}
|
|
|
|
static int __init parse_crash_elf64_headers(void)
|
|
{
|
|
int rc=0;
|
|
Elf64_Ehdr ehdr;
|
|
u64 addr;
|
|
|
|
addr = elfcorehdr_addr;
|
|
|
|
/* Read Elf header */
|
|
rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
/* Do some basic Verification. */
|
|
if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
|
|
(ehdr.e_type != ET_CORE) ||
|
|
!vmcore_elf64_check_arch(&ehdr) ||
|
|
ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
|
|
ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
|
|
ehdr.e_version != EV_CURRENT ||
|
|
ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
|
|
ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
|
|
ehdr.e_phnum == 0) {
|
|
pr_warn("Warning: Core image elf header is not sane\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Read in all elf headers. */
|
|
elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
|
|
ehdr.e_phnum * sizeof(Elf64_Phdr);
|
|
elfcorebuf_sz = elfcorebuf_sz_orig;
|
|
elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
|
|
get_order(elfcorebuf_sz_orig));
|
|
if (!elfcorebuf)
|
|
return -ENOMEM;
|
|
addr = elfcorehdr_addr;
|
|
rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
|
|
if (rc < 0)
|
|
goto fail;
|
|
|
|
/* Merge all PT_NOTE headers into one. */
|
|
rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
|
|
&elfnotes_buf, &elfnotes_sz);
|
|
if (rc)
|
|
goto fail;
|
|
rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
|
|
elfnotes_sz, &vmcore_list);
|
|
if (rc)
|
|
goto fail;
|
|
set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
|
|
return 0;
|
|
fail:
|
|
free_elfcorebuf();
|
|
return rc;
|
|
}
|
|
|
|
static int __init parse_crash_elf32_headers(void)
|
|
{
|
|
int rc=0;
|
|
Elf32_Ehdr ehdr;
|
|
u64 addr;
|
|
|
|
addr = elfcorehdr_addr;
|
|
|
|
/* Read Elf header */
|
|
rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
/* Do some basic Verification. */
|
|
if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
|
|
(ehdr.e_type != ET_CORE) ||
|
|
!elf_check_arch(&ehdr) ||
|
|
ehdr.e_ident[EI_CLASS] != ELFCLASS32||
|
|
ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
|
|
ehdr.e_version != EV_CURRENT ||
|
|
ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
|
|
ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
|
|
ehdr.e_phnum == 0) {
|
|
pr_warn("Warning: Core image elf header is not sane\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Read in all elf headers. */
|
|
elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
|
|
elfcorebuf_sz = elfcorebuf_sz_orig;
|
|
elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
|
|
get_order(elfcorebuf_sz_orig));
|
|
if (!elfcorebuf)
|
|
return -ENOMEM;
|
|
addr = elfcorehdr_addr;
|
|
rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
|
|
if (rc < 0)
|
|
goto fail;
|
|
|
|
/* Merge all PT_NOTE headers into one. */
|
|
rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
|
|
&elfnotes_buf, &elfnotes_sz);
|
|
if (rc)
|
|
goto fail;
|
|
rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
|
|
elfnotes_sz, &vmcore_list);
|
|
if (rc)
|
|
goto fail;
|
|
set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
|
|
return 0;
|
|
fail:
|
|
free_elfcorebuf();
|
|
return rc;
|
|
}
|
|
|
|
static int __init parse_crash_elf_headers(void)
|
|
{
|
|
unsigned char e_ident[EI_NIDENT];
|
|
u64 addr;
|
|
int rc=0;
|
|
|
|
addr = elfcorehdr_addr;
|
|
rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
|
|
if (rc < 0)
|
|
return rc;
|
|
if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
|
|
pr_warn("Warning: Core image elf header not found\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (e_ident[EI_CLASS] == ELFCLASS64) {
|
|
rc = parse_crash_elf64_headers();
|
|
if (rc)
|
|
return rc;
|
|
} else if (e_ident[EI_CLASS] == ELFCLASS32) {
|
|
rc = parse_crash_elf32_headers();
|
|
if (rc)
|
|
return rc;
|
|
} else {
|
|
pr_warn("Warning: Core image elf header is not sane\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Determine vmcore size. */
|
|
vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
|
|
&vmcore_list);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Init function for vmcore module. */
|
|
static int __init vmcore_init(void)
|
|
{
|
|
int rc = 0;
|
|
|
|
/* Allow architectures to allocate ELF header in 2nd kernel */
|
|
rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
|
|
if (rc)
|
|
return rc;
|
|
/*
|
|
* If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
|
|
* then capture the dump.
|
|
*/
|
|
if (!(is_vmcore_usable()))
|
|
return rc;
|
|
rc = parse_crash_elf_headers();
|
|
if (rc) {
|
|
pr_warn("Kdump: vmcore not initialized\n");
|
|
return rc;
|
|
}
|
|
elfcorehdr_free(elfcorehdr_addr);
|
|
elfcorehdr_addr = ELFCORE_ADDR_ERR;
|
|
|
|
proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
|
|
if (proc_vmcore)
|
|
proc_vmcore->size = vmcore_size;
|
|
return 0;
|
|
}
|
|
fs_initcall(vmcore_init);
|
|
|
|
/* Cleanup function for vmcore module. */
|
|
void vmcore_cleanup(void)
|
|
{
|
|
struct list_head *pos, *next;
|
|
|
|
if (proc_vmcore) {
|
|
proc_remove(proc_vmcore);
|
|
proc_vmcore = NULL;
|
|
}
|
|
|
|
/* clear the vmcore list. */
|
|
list_for_each_safe(pos, next, &vmcore_list) {
|
|
struct vmcore *m;
|
|
|
|
m = list_entry(pos, struct vmcore, list);
|
|
list_del(&m->list);
|
|
kfree(m);
|
|
}
|
|
free_elfcorebuf();
|
|
}
|