blob: 86cc0ada5752219c7f1d34380db3d7854bf5d1aa [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
* This code comes from arch/arm64/kernel/crash_dump.c
* Created by: AKASHI Takahiro <>
* Copyright (C) 2017 Linaro Limited
#include <linux/crash_dump.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 in a 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 = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
if (!vaddr)
return -ENOMEM;
if (userbuf) {
if (copy_to_user((char __user *)buf, vaddr + offset, csize)) {
return -EFAULT;
} else
memcpy(buf, vaddr + offset, csize);
return csize;