LoongArch is a new RISC ISA, which is a bit like MIPS or RISC-V. There are currently 3 variants: a reduced 32-bit version (LA32R), a standard 32-bit version (LA32S) and a 64-bit version (LA64). There are 4 privilege levels (PLVs) defined in LoongArch: PLV0~PLV3, from high to low. Kernel runs at PLV0 while applications run at PLV3.