riscv: efi: enable generic EFI compressed boot

Wire up the generic EFI zboot support for RISC-V.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>

RISC-V: ignore xipImage

This built file shows up in "git status" without an explicit ignore.

Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220420184056.7886-3-palmer@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

riscv: Ignore Image.* and loader.bin

Do not track all compressed Image and loader.bin.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

.gitignore: add SPDX License Identifier

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

riscv: Fix gitignore

Tell git to not track the compiled boot/loader and boot/loader.lds
files.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

RISC-V: Build flat and compressed kernel images

This patch extends Linux RISC-V build system to build and install:
Image - Flat uncompressed kernel image
Image.gz - Flat and GZip compressed kernel image

Quiet a few bootloaders (such as Uboot, UEFI, etc) are capable of
booting flat and compressed kernel images. In case of Uboot, booting
Image or Image.gz is achieved using bootm command.

The flat and uncompressed kernel image (i.e. Image) is very useful
in pre-silicon developent and testing because we can create back-door
HEX files for RAM on FPGAs from Image.

Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>