[PATCH] kexec-zImage-arm: simply cmdline-related DTB resizing

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

When resizing a dtb to add the command-line, only resize the DTB once,
rather than once to add the /chosen node, and once to add the bootargs
property.

Also, simply add 1K of overhead (beyond strlen(cmdline)) to the buffer,
to avoid requiring precise knowledge of the size impact of the requested
FTB changes. In particular, some padding is performed when setting
property values, which was not accounted for in the current code, which
caused failures to set the bootargs values in some cases.

Cc: Daniel Mack <zonque at gmail.com>
Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 kexec/arch/arm/kexec-zImage-arm.c |   21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
index 0950897..db29a7b 100644
--- a/kexec/arch/arm/kexec-zImage-arm.c
+++ b/kexec/arch/arm/kexec-zImage-arm.c
@@ -370,31 +370,22 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
 				const char *prop_name = "bootargs";
 				int off;
 
+				dtb_length = fdt_totalsize(dtb_buf) + 1024 +
+					strlen(command_line);
+				dtb_buf = xrealloc(dtb_buf, dtb_length);
+				fdt_set_totalsize(dtb_buf, dtb_length);
+
 				/* check if a /choosen subnode already exists */
 				off = fdt_path_offset(dtb_buf, node_name);
 
-				if (off == -FDT_ERR_NOTFOUND) {
-					dtb_length = fdt_totalsize(dtb_buf)
-							+ strlen(node_name) + 1
-							+ sizeof(struct fdt_node_header)
-							+ FDT_TAGSIZE;
-					dtb_buf = xrealloc(dtb_buf, dtb_length);
-					fdt_set_totalsize(dtb_buf, dtb_length);
+				if (off == -FDT_ERR_NOTFOUND)
 					off = fdt_add_subnode(dtb_buf, off, node_name);
-				}
 
 				if (off < 0) {
 					fprintf(stderr, "FDT: Error adding %s node.\n", node_name);
 					return -1;
 				}
 
-				dtb_length = fdt_totalsize(dtb_buf)
-						+ strlen(prop_name)
-						+ strlen(command_line) + 1
-						+ sizeof(struct fdt_property);
-				dtb_buf = xrealloc(dtb_buf, dtb_length);
-				fdt_set_totalsize(dtb_buf, dtb_length);
-
 				if (fdt_setprop(dtb_buf, off, prop_name,
 						command_line, strlen(command_line) + 1) != 0) {
 					fprintf(stderr, "FDT: Error setting %s/%s property.\n",
-- 
1.7.10.4