I have done make menuconfig for a board defconfig and modified few configurations. When I select save, a new .config was created in the Kernel top directory.
I want to create new defconfig for this .config file created.
Can I copy the .config as a new defconfig and copy to arch/arm/configs/?
$ cp .config arch/arm/configs/board_new_defconfig
I think you have to do just one command and use the created file as you want to.
% make savedefconfig
% cp defconfig arch/arm/configs/my_cool_defconfig
(Pay attention to the filename template that is used for defconfig)
To get all possible targets just run
% make help
As noted by Adam Miller followed by Jeremy, users of Buildroot distribution can use wrappers for that purpose, i.e. (per Buildroot manual, section 8.1):
Linux kernelbarebox bootloaderU-Boot bootloadermake savedefconfig minimizes the generated defconfig skipping redundant configs that are implied by others.