Hi Norman, Can I just turn the Genode's LOG messages and the kernel messages off, then let the GDB monitor use the UART0 channel? If I can, how to do that?
Bests keqin
On ÐÇÆÚÁù, ËÄÔÂ 20, 2013 6:39 pm, Norman Feske wrote: ----------------------------------------------------------------------------------- Hi Keqin,
I suspect that you are mixing up the UART interfaces. The run script relies on two UARTs to be present. UART 0 is used for printing Genode's LOG messages and the kernel messages. The GDB monitor requires a separate channel of communication to the remote GDB. The run script uses UART 1 via the 'uart_drv' for that. UART 1 is then translated by qemu to a TCP connection.
When executing the script on real hardware, you need two UARTs as well. I suspect that you have connected only a single one. Connecting GDB to the UART 0 of the Genode system makes no sense because this one is unrelated to the GDB monitor.
<start name="uart_drv"> <resource name="RAM" quantum="2M"/> <provides> <service name="Terminal"/> </provides> #is that service name "Terminal" should be "/dev/ttyS0" ?
The service name denotes the type of the session. The UART driver provides sessions of type "Terminal" and "Uart". (the "Uart" type is a specialized kind of "Terminal", not important here) In the Genode world "/dev/ttyS0" has no meaning.
<config> <policy label="gdb_monitor" uart="1"/> </config></start>
This configuration tells the UART driver to hand out the second UART (UART 1) to the gdb_monitor client. The numbering starts at 0. UART 0 is typically used by the kernel and Genode's core.
Is that correct?
Does the run script works as intended on Qemu?
Maybe the serial was occupied by the system output?
I guess, you are putting your finger exactly on the issue.
Do you have a way to connect a second UART to your PC? If you consider using a PCI card with additional comports, you will need to make sure that the UART driver uses the I/O ports of the card. (by modifying the function 'io_port_base' in 'os/src/drivers/uart/i8250/main.cc'. You may determine the right values by booting Linux once and executing 'lspci'.
I admit, that sounds a bit awkward and complicated. Normally, you could use the TCP terminal ('gems/src/server/tcp_terminal') as an alternative to an UART interface when using GDB monitor. So there would be no need for multiple UART interfaces. (the TCP terminal provides the "Terminal" interface but works over TCP) Unfortunately, that's not possible when debugging the NIC driver because TCP terminal requires a NIC driver to work.
Cheers Norman