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// SPDX-License-Identifier: GPL-2.0
/*
* Memory preserving reboot related code.
*
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
* Copyright (C) IBM Corporation, 2004. All rights reserved
*/
#include <linux/errno.h>
#include <linux/crash_dump.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/cc_platform.h>
static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
unsigned long offset, int userbuf,
bool encrypted)
{
void *vaddr;
if (!csize)
return 0;
if (encrypted)
vaddr = (__force void *)ioremap_encrypted(pfn << PAGE_SHIFT, PAGE_SIZE);
else
vaddr = (__force void *)ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
if (!vaddr)
return -ENOMEM;
if (userbuf) {
if (copy_to_user((void __user *)buf, vaddr + offset, csize)) {
iounmap((void __iomem *)vaddr);
return -EFAULT;
}
} else
memcpy(buf, vaddr + offset, csize);
iounmap((void __iomem *)vaddr);
return csize;
}
/**
* copy_oldmem_page - copy one page of memory
* @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 the old kernel's memory. For this page, there is no pte
* mapped in the current kernel. We stitch up a pte, similar to kmap_atomic.
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false);
}
/**
* copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the
* memory with the encryption mask set to accommodate kdump on SME-enabled
* machines.
*/
ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
}
ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
return read_from_oldmem(buf, count, ppos, 0,
cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT));
}
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