ref: 1cff9ab4e8412d5c6b6a3cbca720fbc4bcccecd9 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4