New option to avoid copying old root param from 1st kernel cmdline

@@ -53,6 +53,7 @@ extern unsigned char reuse_initrd;
 /* Used for enabling printing message from purgatory code
  * Only has implemented for PPC64 */
 int my_debug;
+int dt_no_old_root;
 
 /* This provides the behaviour of hte existing ppc64 implementation */
 static void pad_structure_block(size_t len) {

@@ -511,6 +512,37 @@ static int comparefunc(const struct dire
 	return strcmp(str1, str2);
 }
 
+/* grab root= from the old command line */
+static void dt_copy_old_root_param(void)
+{
+	FILE *fp;
+	char filename[MAXPATH];
+	char *last_cmdline = NULL;
+	char *p, *old_param;
+	size_t len = 0;
+
+	strcpy(filename, pathname);
+	strcat(filename, "bootargs");
+	fp = fopen(filename, "r");
+	if (fp) {
+		if (getline(&last_cmdline, &len, fp) == -1)
+			die("unable to read %s\n", filename);
+
+		p = strstr(last_cmdline, "root=");
+		if (p) {
+			old_param = strtok(p, " ");
+			len = strlen(local_cmdline);
+			if (len != 0)
+				strcat(local_cmdline, " ");
+			strcat(local_cmdline, old_param);
+		}
+	}
+	if (last_cmdline)
+		free(last_cmdline);
+
+	fclose(fp);
+}
+
 /*
  * put a node (directory) in the property structure.  first properties
  * then children.

@@ -579,8 +611,11 @@ static void putnode(void)
 		reserve(initrd_base, initrd_size);
 	}
 
-	/* Add cmdline to the second kernel.  Check to see if the new
-	 * cmdline has a root=.  If not, use the old root= cmdline.  */
+	/*
+	 * Add cmdline to the second kernel. Use the old root= cmdline if there
+	 * is no root= in the new command line and there's no --dt-no-old-root
+	 * option being used.
+	 */
 	if (!strcmp(basename,"chosen/")) {
 		size_t result;
 		size_t cmd_len = 0;

@@ -598,30 +633,9 @@ static void putnode(void)
 			param = strstr(local_cmdline, "root=");
 		}
 
-		/* ... if not, grab root= from the old command line */
-		if (!param) {
-			FILE *fp;
-			char *last_cmdline = NULL;
-			char *old_param;
-
-			strcpy(filename, pathname);
-			strcat(filename, "bootargs");
-			fp = fopen(filename, "r");
-			if (fp) {
-				if (getline(&last_cmdline, &cmd_len, fp) == -1)
-					die("unable to read %s\n", filename);
-
-				param = strstr(last_cmdline, "root=");
-				if (param) {
-					old_param = strtok(param, " ");
-					if (cmd_len != 0)
-						strcat(local_cmdline, " ");
-					strcat(local_cmdline, old_param);
-				}
-			}
-			if (last_cmdline)
-				free(last_cmdline);
-		}
+		if (!param && !dt_no_old_root)
+			dt_copy_old_root_param();
+
 		strcat(local_cmdline, " ");
 		cmd_len = strlen(local_cmdline);
 		cmd_len = cmd_len + 1;

@@ -31,6 +31,7 @@ extern struct bootblock bb[1];
 /* Used for enabling printing message from purgatory code
  * Only has implemented for PPC64 */
 int my_debug;
+extern int dt_no_old_root;
 
 void reserve(unsigned long long where, unsigned long long length);
 void create_flatten_tree(char **, off_t *, const char *);

@@ -1,7 +1,8 @@
 #ifndef KEXEC_ARCH_ARM_OPTIONS_H
 #define KEXEC_ARCH_ARM_OPTIONS_H
 
-#define OPT_ARCH_MAX   (OPT_MAX+0)
+#define OPT_DT_NO_OLD_ROOT	(OPT_MAX+0)
+#define OPT_ARCH_MAX		(OPT_MAX+1)
 
 #define OPT_APPEND	'a'
 #define OPT_RAMDISK	'r'

@@ -15,6 +16,7 @@
  */
 #define KEXEC_ARCH_OPTIONS \
 	KEXEC_OPTIONS \
+	{ "dt-no-old-root",	0, 0, OPT_DT_NO_OLD_ROOT }, \
 
 #define KEXEC_ARCH_OPT_STR KEXEC_OPT_STR ""
 

@@ -16,6 +16,7 @@
 #include "../../kexec-syscall.h"
 #include "kexec-arm.h"
 #include <arch/options.h>
+#include "../../fs2dt.h"
 
 #define MAX_MEMORY_RANGES 64
 #define MAX_LINE 160

@@ -89,11 +90,37 @@ void arch_usage(void)
 	       "               including the .bss section, as reported\n"
 	       "               by 'arm-linux-size vmlinux'. If not\n"
 	       "               specified, this value is implicitly set\n"
-	       "               to the compressed images size * 4.\n");
+	       "               to the compressed images size * 4.\n"
+	       "     --dt-no-old-root\n"
+	       "               do not reuse old kernel root= param.\n"
+	       "               while creating flatten device tree.\n");
 }
 
 int arch_process_options(int argc, char **argv)
 {
+	/* We look for all options so getopt_long doesn't start reordering
+	 * argv[] before file_type[n].load() gets a look in.
+	 */
+	static const struct option options[] = {
+		KEXEC_ALL_OPTIONS
+		{ 0, 0, NULL, 0 },
+	};
+	static const char short_options[] = KEXEC_ALL_OPT_STR;
+	int opt;
+
+	opterr = 0; /* Don't complain about unrecognized options here */
+	while((opt = getopt_long(argc, argv, short_options, options, 0)) != -1) {
+		switch(opt) {
+		case OPT_DT_NO_OLD_ROOT:
+			dt_no_old_root = 1;
+			break;
+		default:
+			break;
+		}
+	}
+	/* Reset getopt for the next pass; called in other source modules */
+	opterr = 1;
+	optind = 1;
 	return 0;
 }
 

@@ -2,7 +2,8 @@
 #define KEXEC_ARCH_PPC64_OPTIONS_H
 
 #define OPT_ELF64_CORE		(OPT_MAX+0)
-#define OPT_ARCH_MAX		(OPT_MAX+1)
+#define OPT_DT_NO_OLD_ROOT	(OPT_MAX+1)
+#define OPT_ARCH_MAX		(OPT_MAX+2)
 
 /* All 'local' loader options: */
 #define OPT_APPEND		(OPT_ARCH_MAX+0)

@@ -14,6 +15,7 @@
 #define KEXEC_ARCH_OPTIONS \
 	KEXEC_OPTIONS \
 	{ "elf64-core-headers", 0, 0, OPT_ELF64_CORE }, \
+	{ "dt-no-old-root",	0, 0, OPT_DT_NO_OLD_ROOT }, \
 
 #define KEXEC_ARCH_OPT_STR KEXEC_OPT_STR ""
 

@@ -869,6 +869,8 @@ int file_types = sizeof(file_type) / siz
 void arch_usage(void)
 {
 	fprintf(stderr, "     --elf64-core-headers Prepare core headers in ELF64 format\n");
+	fprintf(stderr, "     --dt-no-old-root Do not reuse old kernel root= param.\n" \
+	                "                      while creating flatten device tree.\n");
 }
 
 struct arch_options_t arch_options = {

@@ -895,6 +897,9 @@ int arch_process_options(int argc, char
 		case OPT_ELF64_CORE:
 			arch_options.core_header_type = CORE_TYPE_ELF64;
 			break;
+		case OPT_DT_NO_OLD_ROOT:
+			dt_no_old_root = 1;
+			break;
 		}
 	}
 	/* Reset getopt for the next pass; called in other source modules */