[PATCH] kdump: x86_64: add elfcorehdr command line option

- elfcorehdr= specifies the location of elf core header stored by the
  crashed kernel.  This command line option will be passed by the kexec-tools
  to capture kernel.

Changes in this version :

- Added more comments in kernel-parameters.txt and in code.

Signed-off-by: Murali M Chakravarthy <muralim@in.ibm.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 14 insertions, 4 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 12b7d938a897..dd0bfc291a68 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -475,10 +475,11 @@ running once the system is up.
                         See Documentation/block/as-iosched.txt and
                         Documentation/block/deadline-iosched.txt for details.
 
-        elfcorehdr=     [IA-32]
+        elfcorehdr=     [IA-32, X86_64]
                         Specifies physical address of start of kernel core
-                        image elf header.
-                        See Documentation/kdump.txt for details.
+                        image elf header. Generally kexec loader will
+                        pass this option to capture kernel.
+                        See Documentation/kdump/kdump.txt for details.
 
         enforcing       [SELINUX] Set initial enforcing status.
                         Format: {"0" | "1"}
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index 27c956db0461..f685637a100d 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -898,7 +898,7 @@ static void __init parse_cmdline_early (char ** cmdline_p)
                         }
                 }
 #endif
-#ifdef CONFIG_CRASH_DUMP
+#ifdef CONFIG_PROC_VMCORE
                 /* elfcorehdr= specifies the location of elf core header
                  * stored by the crashed kernel.
                  */
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index ff9620b800c0..a0e0c9ca8f10 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -35,6 +35,7 @@
 #include <asm/processor.h>
 #include <linux/console.h>
 #include <linux/seq_file.h>
+#include <linux/crash_dump.h>
 #include <linux/root_dev.h>
 #include <linux/pci.h>
 #include <linux/acpi.h>
@@ -418,6 +419,14 @@ static __init void parse_cmdline_early (char ** cmdline_p)
                 }
 #endif
 
+#ifdef CONFIG_PROC_VMCORE
+                /* 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.
+                 */
+                else if(!memcmp(from, "elfcorehdr=", 11))
+                        elfcorehdr_addr = memparse(from+11, &from);
+#endif
         next_char:
                 c = *(from++);
                 if (!c)