ref: faac4ddd66794bd981bb94986d58c6e2891d5e5e dir: /sys/src/libc/riscv64/argv0.s/
GLOBL argv0(SB), $XLEN GLOBL _tos(SB), $XLEN GLOBL _privates(SB), $XLEN GLOBL _nprivates(SB), $XLEN