[RFC/PATCH 10/17][Kdump] Routines for copying dump pages
From: Vivek Goyal
Date: Mon Mar 28 2005 - 09:12:58 EST
--- Begin Message ---
From: "Vivek Goyal" <vgoyal@xxxxxxxxxx>
o Moved architecture independent crash_dump.c and crash_dump.h file creation
code from crashdump-memory-preserving-reboot-using-kexec.patch to here. This
makes more logical sense.
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
kernel/crash.c has been renamed kernel/crash_dump.c to clarify it's purpose.
From: Hariprasad Nellitheertha <hari@xxxxxxxxxx>
This patch provides the interfaces necessary to read the dump contents,
treating it as a high memory device.
Signed off by Hariprasad Nellitheertha <hari@xxxxxxxxxx>
Signed-off-by: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
linux-2.6.12-rc1-mm1-1M-root/arch/i386/mm/highmem.c | 18 ++++++
linux-2.6.12-rc1-mm1-1M-root/include/asm-i386/highmem.h | 1
linux-2.6.12-rc1-mm1-1M-root/include/linux/crash_dump.h | 12 ++++
linux-2.6.12-rc1-mm1-1M-root/include/linux/highmem.h | 1
linux-2.6.12-rc1-mm1-1M-root/kernel/Makefile | 1
linux-2.6.12-rc1-mm1-1M-root/kernel/crash_dump.c | 46 ++++++++++++++++
6 files changed, 79 insertions(+)
diff -puN arch/i386/mm/highmem.c~crashdump-routines-for-copying-dump-pages arch/i386/mm/highmem.c
--- linux-2.6.12-rc1-mm1-1M/arch/i386/mm/highmem.c~crashdump-routines-for-copying-dump-pages 2005-03-22 16:14:37.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/arch/i386/mm/highmem.c 2005-03-22 16:14:37.000000000 +0530
@@ -74,6 +74,24 @@ void kunmap_atomic(void *kvaddr, enum km
preempt_check_resched();
}
+/* This is the same as kmap_atomic() but can map memory that doesn't
+ * have a struct page associated with it.
+ */
+void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+{
+ enum fixed_addresses idx;
+ unsigned long vaddr;
+
+ inc_preempt_count();
+
+ idx = type + KM_TYPE_NR*smp_processor_id();
+ vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+ set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
+ __flush_tlb_one(vaddr);
+
+ return (void*) vaddr;
+}
+
struct page *kmap_atomic_to_page(void *ptr)
{
unsigned long idx, vaddr = (unsigned long)ptr;
diff -puN include/asm-i386/highmem.h~crashdump-routines-for-copying-dump-pages include/asm-i386/highmem.h
--- linux-2.6.12-rc1-mm1-1M/include/asm-i386/highmem.h~crashdump-routines-for-copying-dump-pages 2005-03-22 16:14:37.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/include/asm-i386/highmem.h 2005-03-22 16:14:37.000000000 +0530
@@ -70,6 +70,7 @@ void *kmap(struct page *page);
void kunmap(struct page *page);
void *kmap_atomic(struct page *page, enum km_type type);
void kunmap_atomic(void *kvaddr, enum km_type type);
+void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
struct page *kmap_atomic_to_page(void *ptr);
#define flush_cache_kmaps() do { } while (0)
diff -puN /dev/null include/linux/crash_dump.h
--- /dev/null 2004-02-24 02:32:56.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/include/linux/crash_dump.h 2005-03-22 16:14:37.000000000 +0530
@@ -0,0 +1,12 @@
+#ifndef LINUX_CRASH_DUMP_H
+#define LINUX_CRASH_DUMP_H
+
+#ifdef CONFIG_CRASH_DUMP
+#include <linux/kexec.h>
+#include <linux/smp_lock.h>
+#include <linux/device.h>
+#include <linux/proc_fs.h>
+
+extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, int);
+#endif /* CONFIG_CRASH_DUMP */
+#endif /* LINUX_CRASHDUMP_H */
diff -puN include/linux/highmem.h~crashdump-routines-for-copying-dump-pages include/linux/highmem.h
--- linux-2.6.12-rc1-mm1-1M/include/linux/highmem.h~crashdump-routines-for-copying-dump-pages 2005-03-22 16:14:37.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/include/linux/highmem.h 2005-03-22 16:14:37.000000000 +0530
@@ -28,6 +28,7 @@ static inline void *kmap(struct page *pa
#define kmap_atomic(page, idx) page_address(page)
#define kunmap_atomic(addr, idx) do { } while (0)
+#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
#endif /* CONFIG_HIGHMEM */
diff -puN /dev/null kernel/crash_dump.c
--- /dev/null 2004-02-24 02:32:56.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/kernel/crash_dump.c 2005-03-22 16:14:37.000000000 +0530
@@ -0,0 +1,46 @@
+/*
+ * kernel/crash_dump.c - Memory preserving reboot related code.
+ *
+ * Created by: Hariprasad Nellitheertha (hari@xxxxxxxxxx)
+ * Copyright (C) IBM Corporation, 2004. All rights reserved
+ */
+
+#include <linux/smp_lock.h>
+#include <linux/errno.h>
+#include <linux/proc_fs.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/crash_dump.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+/*
+ * Copy a page from "oldmem". 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, int userbuf)
+{
+ void *page, *vaddr;
+
+ if (!csize)
+ return 0;
+
+ page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+ vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
+ copy_page(page, vaddr);
+ kunmap_atomic(vaddr, KM_PTE0);
+
+ if (userbuf) {
+ if (copy_to_user(buf, page, csize)) {
+ kfree(page);
+ return -EFAULT;
+ }
+ } else
+ memcpy(buf, page, csize);
+ kfree(page);
+
+ return 0;
+}
diff -puN kernel/Makefile~crashdump-routines-for-copying-dump-pages kernel/Makefile
--- linux-2.6.12-rc1-mm1-1M/kernel/Makefile~crashdump-routines-for-copying-dump-pages 2005-03-22 16:14:37.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/kernel/Makefile 2005-03-22 16:14:37.000000000 +0530
@@ -29,6 +29,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_SYSFS) += ksysfs.o
obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
+obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_SECCOMP) += seccomp.o
ifneq ($(CONFIG_IA64),y)
_
--- End Message ---