1 files changed, 35 insertions, 51 deletions

diff --git a/kernel/crash_dump.c b/kernel/crash_dump.c
index 334c37f5218..c766ee54c0b 100644
--- a/kernel/crash_dump.c
+++ b/kernel/crash_dump.c
@@ -1,61 +1,45 @@
-/*
- *	kernel/crash_dump.c - Memory preserving reboot related code.
- *
- *	Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
- *	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/kernel.h>
 #include <linux/crash_dump.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/export.h>
 
-#include <asm/io.h>
-#include <asm/uaccess.h>
+/*
+ * If we have booted due to a crash, max_pfn will be a very low value. We need
+ * to know the amount of memory that the previous kernel used.
+ */
+unsigned long saved_max_pfn;
 
-/* Stores the physical address of elf header of crash image. */
+/*
+ * stores the physical address of elf header of crash image
+ *
+ * Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
+ * is_kdump_kernel() to determine if we are booting after a panic. Hence put
+ * it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
+ */
 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
 
-/**
- * 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().
+/*
+ * stores the size of elf header of crash image
+ */
+unsigned long long elfcorehdr_size;
+
+/*
+ * elfcorehdr= specifies the location of elf core header stored by the crashed
+ * kernel. This option will be passed by kexec loader to the capture kernel.
  *
- * 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.
+ * Syntax: elfcorehdr=[size[KMG]@]offset[KMG]
  */
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
-				size_t csize, unsigned long offset, int userbuf)
+static int __init setup_elfcorehdr(char *arg)
 {
-	void *page, *vaddr;
-
-	if (!csize)
-		return 0;
-
-	page = kmalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!page)
-		return -ENOMEM;
-
-	vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
-	copy_page(page, vaddr);
-	kunmap_atomic(vaddr, KM_PTE0);
-
-	if (userbuf) {
-		if (copy_to_user(buf, (page + offset), csize)) {
-			kfree(page);
-			return -EFAULT;
-		}
-	} else {
-		memcpy(buf, (page + offset), csize);
+	char *end;
+	if (!arg)
+		return -EINVAL;
+	elfcorehdr_addr = memparse(arg, &end);
+	if (*end == '@') {
+		elfcorehdr_size = elfcorehdr_addr;
+		elfcorehdr_addr = memparse(end + 1, &end);
 	}
-
-	kfree(page);
-	return csize;
+	return end > arg ? 0 : -EINVAL;
 }
+early_param("elfcorehdr", setup_elfcorehdr);