From ff12055f9820ac8af620050f5d75e157a9a2fca3 Mon Sep 17 00:00:00 2001
From: Jeffy Chen <jeffy.chen@rock-chips.com>
Date: Sat, 15 Dec 2018 21:24:07 +0800
Subject: [PATCH] init/initramfs: Add dump_initrd command line option

Add a dump_initrd option to allow dumping /initrd.image after successful
unpack.

Require BLK_DEV_RAM=y.

Change-Id: I77a41867afa7b4a51604a5153792a49efbab6189
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
---
 init/initramfs.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/init/initramfs.c b/init/initramfs.c
index 3340bf219a20..d53138c40639 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -525,6 +525,17 @@ static int __init retain_initrd_param(char *str)
 }
 __setup("retain_initrd", retain_initrd_param);
 
+static int __initdata do_dump_initrd;
+
+static int __init dump_initrd_param(char *str)
+{
+	if (*str)
+		return 0;
+	do_dump_initrd = 1;
+	return 1;
+}
+__setup("dump_initrd", dump_initrd_param);
+
 extern char __initramfs_start[];
 extern unsigned long __initramfs_size;
 #include <linux/initrd.h>
@@ -642,6 +653,9 @@ static int __init populate_rootfs(void)
 		err = unpack_to_rootfs((char *)initrd_start,
 			initrd_end - initrd_start);
 		if (!err) {
+			if (do_dump_initrd)
+				goto dump;
+
 			free_initrd();
 			goto done;
 		} else {
@@ -650,6 +664,7 @@ static int __init populate_rootfs(void)
 		}
 		printk(KERN_INFO "rootfs image is not initramfs (%s)"
 				"; looks like an initrd\n", err);
+	dump:
 		fd = sys_open("/initrd.image",
 			      O_WRONLY|O_CREAT, 0700);
 		if (fd >= 0) {