[PATCH] kdump: Routines for copying dump pages
This patch provides the interfaces necessary to read the dump contents, treating it as a high memory device. Signed off by Hariprasad Nellitheertha <hari@in.ibm.com> Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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6 changed files with 83 additions and 0 deletions
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@ -75,6 +75,24 @@ void kunmap_atomic(void *kvaddr, enum km_type type)
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preempt_check_resched();
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}
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/* This is the same as kmap_atomic() but can map memory that doesn't
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* have a struct page associated with it.
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*/
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void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
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{
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enum fixed_addresses idx;
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unsigned long vaddr;
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inc_preempt_count();
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idx = type + KM_TYPE_NR*smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
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__flush_tlb_one(vaddr);
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return (void*) vaddr;
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}
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struct page *kmap_atomic_to_page(void *ptr)
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{
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unsigned long idx, vaddr = (unsigned long)ptr;
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@ -70,6 +70,7 @@ void *kmap(struct page *page);
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void kunmap(struct page *page);
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void *kmap_atomic(struct page *page, enum km_type type);
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void kunmap_atomic(void *kvaddr, enum km_type type);
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void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
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struct page *kmap_atomic_to_page(void *ptr);
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#define flush_cache_kmaps() do { } while (0)
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13
include/linux/crash_dump.h
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13
include/linux/crash_dump.h
Normal file
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@ -0,0 +1,13 @@
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#ifndef LINUX_CRASH_DUMP_H
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#define LINUX_CRASH_DUMP_H
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#ifdef CONFIG_CRASH_DUMP
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#include <linux/kexec.h>
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#include <linux/smp_lock.h>
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#include <linux/device.h>
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#include <linux/proc_fs.h>
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extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
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unsigned long, int);
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#endif /* CONFIG_CRASH_DUMP */
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#endif /* LINUX_CRASHDUMP_H */
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@ -28,6 +28,7 @@ static inline void *kmap(struct page *page)
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#define kmap_atomic(page, idx) page_address(page)
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#define kunmap_atomic(addr, idx) do { } while (0)
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#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
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#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
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#endif /* CONFIG_HIGHMEM */
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@ -28,6 +28,7 @@ obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
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obj-$(CONFIG_KPROBES) += kprobes.o
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obj-$(CONFIG_SYSFS) += ksysfs.o
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obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
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obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
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obj-$(CONFIG_SECCOMP) += seccomp.o
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ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
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49
kernel/crash_dump.c
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49
kernel/crash_dump.c
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@ -0,0 +1,49 @@
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/*
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* kernel/crash_dump.c - 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/smp_lock.h>
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#include <linux/errno.h>
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#include <linux/proc_fs.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
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#include <linux/crash_dump.h>
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#include <asm/io.h>
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#include <asm/uaccess.h>
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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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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 *page, *vaddr;
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if (!csize)
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return 0;
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page = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (!page)
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return -ENOMEM;
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vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
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copy_page(page, vaddr);
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kunmap_atomic(vaddr, KM_PTE0);
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if (userbuf) {
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if (copy_to_user(buf, (page + offset), csize)) {
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kfree(page);
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return -EFAULT;
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}
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} else {
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memcpy(buf, (page + offset), csize);
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}
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kfree(page);
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return csize;
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}
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