57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* arch/sw_64/kernel/crash_dump.c
|
|
*
|
|
* Copyright (C) 2019 JN
|
|
* Author: He Sheng
|
|
*
|
|
* This code is taken from arch/x86/kernel/crash_dump_64.c
|
|
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
|
|
* Copyright (C) IBM Corporation, 2004. All rights reserved
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/uaccess.h>
|
|
#include <linux/io.h>
|
|
|
|
/**
|
|
* copy_oldmem_page() - copy one page from old kernel memory
|
|
* @pfn: page frame number to be copied
|
|
* @buf: buffer where the copied page is placed
|
|
* @csize: number of bytes to copy
|
|
* @offset: offset in bytes into the page
|
|
* @userbuf: if set, @buf is int he user address space
|
|
*
|
|
* This function copies one page from old kernel memory into buffer pointed by
|
|
* @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
|
|
* copied or negative error in case of failure.
|
|
*/
|
|
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
|
|
size_t csize, unsigned long offset,
|
|
int userbuf)
|
|
{
|
|
void *vaddr;
|
|
|
|
if (!csize)
|
|
return 0;
|
|
|
|
vaddr = ioremap(__pfn_to_phys(pfn), PAGE_SIZE);
|
|
if (!vaddr)
|
|
return -ENOMEM;
|
|
|
|
if (userbuf) {
|
|
if (copy_to_user(buf, vaddr + offset, csize)) {
|
|
iounmap(vaddr);
|
|
return -EFAULT;
|
|
}
|
|
} else {
|
|
memcpy(buf, vaddr + offset, csize);
|
|
}
|
|
|
|
iounmap(vaddr);
|
|
return csize;
|
|
}
|