[PATCH] kexec: Provide an option to use new kexec system call

[Baoquan He]

On 08/13/14 at 11:06am, Vivek Goyal wrote:
> +/* New file based kexec system call related code */
> +static int do_kexec_file_load(int fileind, int argc, char **argv,
> +			unsigned long flags) {
> +
> +	char *kernel;

........

> +	kernel_fd = open(kernel, O_RDONLY);
> +	if (kernel_fd == -1) {
> +		fprintf(stderr, "Failed to open file %s:%s\n", kernel,
> +				strerror(errno));
> +		return -1;
> +	}
> +
> +	/* slurp in the input kernel */
> +	kernel_buf = slurp_decompress_file(kernel, &kernel_size);
> +
> +	for (i = 0; i < file_types; i++) {
> +		if (file_type[i].probe(kernel_buf, kernel_size) >= 0)
> +			break;
> +	}
> +
> +	if (i == file_types) {
> +		fprintf(stderr, "Cannot determine the file type " "of %s\n",
> +				kernel);
> +		return -1;
> +	}
> +
> +	ret = file_type[i].load(argc, argv, kernel_buf, kernel_size, &info);
> +	if (ret < 0) {
> +		fprintf(stderr, "Cannot load %s\n", kernel);
> +		return ret;
> +	}
> +
> +	if (!is_kexec_file_load_implemented()) {

Hi Vivek,

Can we put this check earlier, maybe before kernel file openning? Since
if this syscall is not implemented, we don't have to do the opening or
loading things.

Thanks
Baoquan


> +		fprintf(stderr, "syscall kexec_file_load not available.\n");
> +		return -1;
> +	}
> +
> +	/*
> +	 * If there is no initramfs, set KEXEC_FILE_NO_INITRAMFS flag so that
> +	 * kernel does not return error with negative initrd_fd.
> +	 */
> +	if (info.initrd_fd == -1)
> +		info.kexec_flags |= KEXEC_FILE_NO_INITRAMFS;
> +
> +	ret = kexec_file_load(kernel_fd, info.initrd_fd, info.command_line_len,
> +			info.command_line, info.kexec_flags);
> +	if (ret != 0)
> +		fprintf(stderr, "kexec_file_load failed: %s\n",
> +					strerror(errno));
> +	return ret;
> +}
> +
>