Early console using Arm compatible semihosting

modulename: earlycon-semihost.ko

configname: CONFIG_SERIAL_EARLYCON_SEMIHOST

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Early console using Arm compatible semihosting
In linux kernel since version 6.3 (release Date: 2023-04-23)  
Support for early debug console using Arm compatible semihosting.
This enables the console before standard serial driver is probed.
This is enabled with "earlycon=smh" on the kernel command line.
The console is enabled when early_param is processed.

source code:
drivers/tty/serial/earlycon-semihost.c