kexec ppc64: fix misaligned cmdline

If the cmdline changes between boots, we can get misalignment of the
bootargs entry, which in turn corrupts our device tree blob and hence
kills our kexec boot.  Also, if there was no /chosen/bootargs
previously, we'd never add a new one.

This ignores the bootargs while parsing the tree and inserts it later.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 63 insertions, 32 deletions

diff --git a/kexec/arch/ppc64/fs2dt.c b/kexec/arch/ppc64/fs2dt.c
index 77ebb50..348ff1b 100644
--- a/kexec/arch/ppc64/fs2dt.c
+++ b/kexec/arch/ppc64/fs2dt.c
@@ -18,6 +18,7 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#define _GNU_SOURCE
 #include <sys/types.h>
 #include <sys/stat.h>
 
@@ -233,6 +234,12 @@ static void putprops(char *fn, struct dirent **nlist, int numlist)
 		    !reuse_initrd)
 				continue;
 
+		/* This property will be created later in putnode() So
+		 * ignore it now.
+		 */
+		if (!strcmp(dp->d_name, "bootargs"))
+			continue;
+
 		if (! S_ISREG(statbuf.st_mode))
 			continue;
 
@@ -257,38 +264,6 @@ static void putprops(char *fn, struct dirent **nlist, int numlist)
 
 		checkprop(fn, dt, len);
 
-		/* Get the cmdline from the device-tree and modify it */
-		if (!strcmp(dp->d_name, "bootargs")) {
-			int cmd_len;
-			char temp_cmdline[COMMAND_LINE_SIZE] = { "" };
-			char *param = NULL;
-			cmd_len = strlen(local_cmdline);
-			if (cmd_len != 0) {
-				param = strstr(local_cmdline, "crashkernel=");
-				if (param)
-					crash_param = 1;
-				param = strstr(local_cmdline, "root=");
-			}
-			if (!param) {
-				char *old_param;
-				memcpy(temp_cmdline, dt, len);
-				param = strstr(temp_cmdline, "root=");
-				if (param) {
-					old_param = strtok(param, " ");
-					if (cmd_len != 0)
-						strcat(local_cmdline, " ");
-					strcat(local_cmdline, old_param);
-				}
-			}
-			strcat(local_cmdline, " ");
-			cmd_len = strlen(local_cmdline);
-			cmd_len = cmd_len + 1;
-			memcpy(dt, local_cmdline,cmd_len);
-			len = cmd_len;
-			*dt_len = cmd_len;
-			fprintf(stderr, "Modified cmdline:%s\n", local_cmdline);
-		}
-
 		dt += (len + 3)/4;
 		if (!strcmp(dp->d_name, "reg") && usablemem_rgns.size)
 			add_usable_mem_property(fd, len);
@@ -385,6 +360,62 @@ 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.  */
+	if (!strcmp(basename,"/chosen/")) {
+		size_t cmd_len = 0;
+		char *param = NULL;
+
+		cmd_len = strlen(local_cmdline);
+		if (cmd_len != 0) {
+			param = strstr(local_cmdline, "crashkernel=");
+			if (param)
+				crash_param = 1;
+			/* does the new cmdline have a root= ? ... */
+			param = strstr(local_cmdline, "root=");
+		}
+
+		/* ... if not, grab root= from the old command line */
+		if (!param) {
+			char filename[MAXPATH];
+			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);
+		}
+		strcat(local_cmdline, " ");
+		cmd_len = strlen(local_cmdline);
+		cmd_len = cmd_len + 1;
+
+		/* add new bootargs */
+		*dt++ = 3;
+		*dt++ = cmd_len;
+		*dt++ = propnum("bootargs");
+		if ((cmd_len >= 8) && ((unsigned long)dt & 0x4))
+			dt++;
+		memcpy(dt, local_cmdline,cmd_len);
+		dt += (cmd_len + 3)/4;
+
+		fprintf(stderr, "Modified cmdline:%s\n", local_cmdline);
+	}
+
 	for (i=0; i < numlist; i++) {
 		dp = namelist[i];
 		strcpy(dn, dp->d_name);