Who pass the kernel boot args?

hello,

I found that the uClinux configuration chose pass command line rather than use default command line, but my confuse is:

Who pass the boot args to the kernel, you know we just download the image with nios2-download rather than u-boot,

I find it that the dts file have a boot args, but it does not tell the kernel where the initrd file is, even more, with the sopc-create-heads-file method, I've no idea where the boot args come from, does the kernel do the choice?

:(

regards