ref: fd8a2d81c3ddf6584d2b47f1b8efe30b66beb7b5 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4