7e015a2798
Replace kmap_atomic_pfn() with kmap_local_pfn() which is preemptible and can take page faults. Remove the indirection of the dump page and the related cruft which is not longer required. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201118204007.670851839@linutronix.de
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
// 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/slab.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/crash_dump.h>
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
static inline bool is_crashed_pfn_valid(unsigned long pfn)
|
|
{
|
|
#ifndef CONFIG_X86_PAE
|
|
/*
|
|
* non-PAE kdump kernel executed from a PAE one will crop high pte
|
|
* bits and poke unwanted space counting again from address 0, we
|
|
* don't want that. pte must fit into unsigned long. In fact the
|
|
* test checks high 12 bits for being zero (pfn will be shifted left
|
|
* by PAGE_SHIFT).
|
|
*/
|
|
return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn;
|
|
#else
|
|
return true;
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
|
|
if (!is_crashed_pfn_valid(pfn))
|
|
return -EFAULT;
|
|
|
|
vaddr = kmap_local_pfn(pfn);
|
|
|
|
if (!userbuf) {
|
|
memcpy(buf, vaddr + offset, csize);
|
|
} else {
|
|
if (copy_to_user(buf, vaddr + offset, csize))
|
|
csize = -EFAULT;
|
|
}
|
|
|
|
kunmap_local(vaddr);
|
|
|
|
return csize;
|
|
}
|