// SPDX-License-Identifier: GPL-2.0
|
#include <linux/highmem.h>
|
#include <linux/memblock.h>
|
#include <linux/crash_dump.h>
|
#include <linux/uaccess.h>
|
#include <linux/slab.h>
|
|
/**
|
* copy_oldmem_page - copy one page from "oldmem"
|
* @pfn: page frame number to be copied
|
* @buf: target memory address for the copy; this can be in kernel address
|
* space or user address space (see @userbuf)
|
* @csize: number of bytes to copy
|
* @offset: offset in bytes into the page (based on pfn) to begin the copy
|
* @userbuf: if set, @buf is in user address space, use copy_to_user(),
|
* otherwise @buf is in kernel address space, use memcpy().
|
*
|
* Copy a page from "oldmem". For this page, there might be no pte mapped
|
* in the current kernel.
|
*/
|
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 = kmap_local_pfn(pfn);
|
|
if (!userbuf) {
|
memcpy(buf, vaddr + offset, csize);
|
} else {
|
if (copy_to_user(buf, vaddr + offset, csize))
|
csize = -EFAULT;
|
}
|
|
return csize;
|
}
|
