[PATCH 2/3] kexec: pass initrd position in dtb

[Dave Young]

On 01/22/14 at 06:52pm, Wang Nan wrote:
> This patch append the position of initrd to dtb when loading arm kernel and
> initrd without using atag.
> 
> Signed-off-by: Wang Nan <wangnan0 at huawei.com>
> Cc: Simon Horman <horms at verge.net.au>
> Cc: Dave Young <dyoung at redhat.com>
> Cc: Geng Hui <hui.geng at huawei.com>
> ---
>  kexec/arch/arm/kexec-zImage-arm.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
> index 4547765..6d6b239 100644
> --- a/kexec/arch/arm/kexec-zImage-arm.c
> +++ b/kexec/arch/arm/kexec-zImage-arm.c
> @@ -417,6 +417,41 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
>  		if (ramdisk) {
>  			add_segment(info, ramdisk_buf, initrd_size,
>  			            initrd_base, initrd_size);
> +			const char *node_name = "/chosen";
> +			const char *prop_start_name = "linux,initrd-start";
> +			const char *prop_end_name = "linux,initrd-end";
> +			int off;
> +
> +			dtb_length = fdt_totalsize(dtb_buf) + 1024 + 8;

why +8 here? is it the "/chosen" string size? if yes please change to use
strlen.

> +			dtb_buf = xrealloc(dtb_buf, dtb_length);

Should check xrealloc return value here.

Since it is very similar with the code for appending cmdline, at least
creating a share function for adding a new node looks better.

> +			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)
> +				off = fdt_add_subnode(dtb_buf, off, node_name);
> +
> +			if (off < 0) {
> +				fprintf(stderr, "FDT: Error adding %s node.\n", node_name);
> +				return -1;
> +			}
> +
> +			unsigned long start, end;
> +			start = cpu_to_be32((unsigned long)(initrd_base));
> +			end = cpu_to_be32((unsigned long)(initrd_base + initrd_size));
> +			if (fdt_setprop(dtb_buf, off, prop_start_name,
> +						&start, sizeof(start)) != 0) {
> +				fprintf(stderr, "FDT: Error setting %s/%s property.\n",
> +						node_name, prop_start_name);
> +				return -1;
> +			}
> +			if (fdt_setprop(dtb_buf, off, prop_end_name,
> +						&end, sizeof(end)) != 0) {
> +				fprintf(stderr, "FDT: Error setting %s/%s property.\n",
> +						node_name, prop_end_name);
> +				return -1;
> +			}
>  		}
>  
>  		/* Stick the dtb at the end of the initrd and page
> -- 
> 1.8.4
> 
> 
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