the baud rate meesage out put by gdbserver

[loody]

Dear all:
I put my gdbserver on my mips target and when I execute it, it will
pop out the message as below:

# ./gdbserver /dev/ttyS1 test
Process test-ci-app created; pid = 149
Uart baud =9600
Remote debugging using /dev/ttyS1


My question is:
where and how gdbserver knows the baud rate setting as 9600 above.
Is gdbserver calculate the value or it get the information from kernel?
appreciate your help,
miloody