kexec: remove KMSG_DUMP_KEXEC

KMSG_DUMP_KEXEC is useless because we already save kernel messages inside
/proc/vmcore, and it is unsafe to allow modules to do other stuffs in a
crash dump scenario.

[akpm@linux-foundation.org: fix powerpc build]
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/platforms/pseries/nvram.c

@@ -638,7 +638,6 @@ static void oops_to_nvram(struct kmsg_dumper *dumper,
 		/* These are almost always orderly shutdowns. */
 		return;
 	case KMSG_DUMP_OOPS:
-	case KMSG_DUMP_KEXEC:
 		break;
 	case KMSG_DUMP_PANIC:
 		panicking = true;

drivers/char/ramoops.c

@@ -83,8 +83,7 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
 	struct timeval timestamp;
 
 	if (reason != KMSG_DUMP_OOPS &&
-	    reason != KMSG_DUMP_PANIC &&
-	    reason != KMSG_DUMP_KEXEC)
+	    reason != KMSG_DUMP_PANIC)
 		return;
 
 	/* Only dump oopses if dump_oops is set */

drivers/mtd/mtdoops.c

@@ -315,8 +315,7 @@ static void mtdoops_do_dump(struct kmsg_dumper *dumper,
 	char *dst;
 
 	if (reason != KMSG_DUMP_OOPS &&
-	    reason != KMSG_DUMP_PANIC &&
-	    reason != KMSG_DUMP_KEXEC)
+	    reason != KMSG_DUMP_PANIC)
 		return;
 
 	/* Only dump oopses if dump_oops is set */

include/linux/kmsg_dump.h

@@ -18,7 +18,6 @@
 enum kmsg_dump_reason {
 	KMSG_DUMP_OOPS,
 	KMSG_DUMP_PANIC,
-	KMSG_DUMP_KEXEC,
 	KMSG_DUMP_RESTART,
 	KMSG_DUMP_HALT,
 	KMSG_DUMP_POWEROFF,

kernel/kexec.c

@@ -32,7 +32,6 @@
 #include <linux/console.h>
 #include <linux/vmalloc.h>
 #include <linux/swap.h>
-#include <linux/kmsg_dump.h>
 #include <linux/syscore_ops.h>
 
 #include <asm/page.h>
@@ -1094,8 +1093,6 @@ void crash_kexec(struct pt_regs *regs)
 		if (kexec_crash_image) {
 			struct pt_regs fixed_regs;
 
-			kmsg_dump(KMSG_DUMP_KEXEC);
-
 			crash_setup_regs(&fixed_regs, regs);
 			crash_save_vmcoreinfo();
 			machine_crash_shutdown(&fixed_regs);