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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>
- 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);
- set_iounmap_nonlazy();
- 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, sev_active());
- }
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