93a72052be
The Xen PV drivers in a crashed HVM guest can not connect to the dom0 backend drivers because both frontend and backend drivers are still in connected state. To run the connection reset function only in case of a crashdump, the is_kdump_kernel() function needs to be available for the PV driver modules. Consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn into kernel/crash_dump.c Also export elfcorehdr_addr to make is_kdump_kernel() usable for modules. Leave 'elfcorehdr' as early_param(). This changes powerpc from __setup() to early_param(). It adds an address range check from x86 also on ia64 and powerpc. [akpm@linux-foundation.org: additional #includes] [akpm@linux-foundation.org: remove elfcorehdr_addr export] [akpm@linux-foundation.org: fix for Tejun's mm/nobootmem.c changes] Signed-off-by: Olaf Hering <olaf@aepfle.de> Cc: Russell King <rmk@arm.linux.org.uk> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
95 lines
2.5 KiB
C
95 lines
2.5 KiB
C
/*
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* Memory preserving reboot related code.
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*
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* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
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* Copyright (C) IBM Corporation, 2004. All rights reserved
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*/
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/highmem.h>
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#include <linux/crash_dump.h>
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#include <asm/uaccess.h>
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static void *kdump_buf_page;
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static inline bool is_crashed_pfn_valid(unsigned long pfn)
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{
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#ifndef CONFIG_X86_PAE
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/*
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* non-PAE kdump kernel executed from a PAE one will crop high pte
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* bits and poke unwanted space counting again from address 0, we
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* don't want that. pte must fit into unsigned long. In fact the
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* test checks high 12 bits for being zero (pfn will be shifted left
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* by PAGE_SHIFT).
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*/
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return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn;
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#else
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return true;
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#endif
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}
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/**
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* copy_oldmem_page - copy one page from "oldmem"
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* @pfn: page frame number to be copied
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* @buf: target memory address for the copy; this can be in kernel address
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* space or user address space (see @userbuf)
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* @csize: number of bytes to copy
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* @offset: offset in bytes into the page (based on pfn) to begin the copy
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* @userbuf: if set, @buf is in user address space, use copy_to_user(),
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* otherwise @buf is in kernel address space, use memcpy().
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*
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* Copy a page from "oldmem". For this page, there is no pte mapped
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* in the current kernel. We stitch up a pte, similar to kmap_atomic.
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*
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* Calling copy_to_user() in atomic context is not desirable. Hence first
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* copying the data to a pre-allocated kernel page and then copying to user
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* space in non-atomic context.
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*/
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ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
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size_t csize, unsigned long offset, int userbuf)
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{
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void *vaddr;
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if (!csize)
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return 0;
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if (!is_crashed_pfn_valid(pfn))
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return -EFAULT;
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vaddr = kmap_atomic_pfn(pfn);
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if (!userbuf) {
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memcpy(buf, (vaddr + offset), csize);
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kunmap_atomic(vaddr, KM_PTE0);
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} else {
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if (!kdump_buf_page) {
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printk(KERN_WARNING "Kdump: Kdump buffer page not"
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" allocated\n");
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kunmap_atomic(vaddr, KM_PTE0);
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return -EFAULT;
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}
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copy_page(kdump_buf_page, vaddr);
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kunmap_atomic(vaddr, KM_PTE0);
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if (copy_to_user(buf, (kdump_buf_page + offset), csize))
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return -EFAULT;
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}
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return csize;
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}
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static int __init kdump_buf_page_init(void)
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{
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int ret = 0;
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kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (!kdump_buf_page) {
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printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
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" page\n");
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ret = -ENOMEM;
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}
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return ret;
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}
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arch_initcall(kdump_buf_page_init);
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