[PATCH] x86_64: x86_64 add crashdump trigger points

o Start booting into the capture kernel after an Oops if system is in a
  unrecoverable state. System will boot into the capture kernel, if one is
  pre-loaded by the user, and capture the kernel core dump.

o One of the following conditions should be true to trigger the booting of
  capture kernel.
        - panic_on_oops is set.
        - pid of current thread is 0
        - pid of current thread is 1
        - Oops happened inside interrupt context.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/traps.c

@@ -30,6 +30,7 @@
 #include <linux/moduleparam.h>
 #include <linux/nmi.h>
 #include <linux/kprobes.h>
+#include <linux/kexec.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -433,6 +434,8 @@ void __kprobes __die(const char * str, struct pt_regs * regs, long err)
 	printk(KERN_ALERT "RIP ");
 	printk_address(regs->rip); 
 	printk(" RSP <%016lx>\n", regs->rsp); 
+	if (kexec_should_crash(current))
+		crash_kexec(regs);
 }
 
 void die(const char * str, struct pt_regs * regs, long err)
@@ -455,6 +458,8 @@ void __kprobes die_nmi(char *str, struct pt_regs *regs)
 	 */
 	printk(str, safe_smp_processor_id());
 	show_registers(regs);
+	if (kexec_should_crash(current))
+		crash_kexec(regs);
 	if (panic_on_timeout || panic_on_oops)
 		panic("nmi watchdog");
 	printk("console shuts up ...\n");