STLinux -- Network console logging support

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Network console logging support

This support implements the kernel level network logging via UDP.

The netlogging is useful in a number of scenarios:

if remotely managed systems with no serial cable logging keep crashing without any trace of an oops message in the userspace log
if the amount of logging is so high that a serial console cannot hold it
in cases where logged messages disturb the debugged subsystem

The netconsole module can be used either built-in or as a module.

To use it add the following kernel parameter in commnd line:

netconsole=[src-port]@[src-ip]/[dev],[dest-port]@dest-ip/[dest-macaddr]

where:

src-port: source for UDP packets (defaults to 6665)
src-ip: source IP to use (interface address)
dev: network interface (eth0)
dest-port: port for logging agent (6666)
dest-ip: IP address for logging agent
dest-macaddr: ethernet MAC address for logging agent (broadcast)

Using netconsole as built-in

when building the kernel enable "Network console logging support (EXPERIMENTAL)" in the "Device Drivers"->"Networking support" menu
make ARCH=sh CROSS_COMPILE=sh4-linux- vmlinux

Note: built-in netconsole starts immediately after the TCP stack is initialized and attempts to bring up the supplied dev at the supplied address.

Using netconsole as dynamic module

on the host
- when building the kernel set the "Network console logging support (EXPERIMENTAL)" with M value
- make ARCH=sh CROSS_COMPILE=sh4-linux- vmlinux
- make ARCH=sh CROSS_COMPILE=sh4-linux- modules
- copy the drivers/net/netconsole.ko file object in your rootFS
- boot your target
on the target
On the remote host you could execute:

For more datails see the kernel documentation (Documentation/networking/netconsole.txt)

Example

This example shows a Linux Kernel boot using netconsole support.

Platforms connection
     _____________            _______________
    |             |          |               |
    | ST Platform |          |   LINUX HOST  |
    |_____________|          |_______________|
          |                           |
          |          UDP/IP  	      |
          |___________________________|

   local IP = 192.168.1.108	remote IP = 192.168.1.110
   local port = 6665		remote eth addr = 6666

sample startup of the netconsole on the server 
[root@linuxHOST root]# netcat -u -l -p 6666 -v
Received packet from 192.168.1.108:6665 -> 192.168.1.110:6666 (local)
Linux version 2.6.10-rc1-sim (cavagiu@lxmcdt7) 
(gcc version 3.4.3) #32 Mon Feb 21 16:26:27 CET 2005
STMicroelectronics ST220 Eval initialisation
EPLD version: 2.0 PCB revision: B
Built 1 zonelists
Kernel command line: console=ttyAS0,115200 
root=/dev/nfs 
nfsroot=164.130.129.16:/opt/STM/STLinux-2.0/devkit/sh4/target/ 
timeo=4,rsize=1024 
ip=192.168.1.108:164.130.129.16:192.168.1.254:255.255.255.0:cavagiu::off 
mtdparts=Onboard_Flash:256k,2048k,- 
netconsole=@192.168.1.108/eth0,@192.168.1.110/
netconsole: local port 6665
netconsole: local IP 192.168.1.108
netconsole: interface eth0
netconsole: remote port 6666
netconsole: remote IP 192.168.1.110
netconsole: remote ethernet address ff:ff:ff:ff:ff:ff
PID hash table entries: 512 (order: 9, 8192 bytes)
Calculated peripheral clock value 69065976 differs from sh_pclk 
value 66000000, fixing..
Calculated peripheral clock value 66600000 differs from probed 
or set value 69065976, fixing..
CPU clock: 199.80MHz
Bus clock: 133.20MHz
Module clock: 66.60MHz
Bus clock: 133.20MHz
Interval = 166500
Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
Memory: 62592k/65536k available (1806k kernel code, 2852k 
reserved, 217k data, 68k init)
Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
CPU: 
NET: Registered protocol family 16
SH Virtual Bus initialized
lirc_dev: IR Remote Control driver registered, at major 61
STM Lirc plugin init
lirc_dev: lirc_register_plugin:sample_rate: 0
STPIO layer initialised
STMicroelectronics ASC driver initialized
asc_init: check the clock
ttyAS0 at MMIO 0xb8330000 (irq = 185) is a asc
asc_init: check the clock
ttyAS1 at MMIO 0xb8331000 (irq = 186) is a asc
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
smc91x.c: v1.1, sep 22 2004 by Nicolas Pitre 
eth0: SMC91C11xFD (rev 1) at 0xa1800300 IRQ 11
eth0: Ethernet addr: 00:80:e1:12:02:30
netconsole: device eth0 not up yet, forcing it
eth0: link down
eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
netconsole: network logging started
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
ide setup: hwif 0x88224f3c, dma_base 0xb4500000, ports 0x400
    ide0: MMIO-DMA
elevator: using anticipatory as default io scheduler
NET: Registered protocol family 2
IP: routing cache hash table of 512 buckets, 4Kbytes
TCP: Hash tables configured (established 4096 bind 8192)
NET: Registered protocol family 1
IP-Config: Complete:
      device=eth0, addr=192.168.1.108, mask=255.255.255.0, gw=192.168.1.254,
     host=cavagiu, domain=, nis-domain=(none),
     bootserver=164.130.129.16, rootserver=164.130.129.16, rootpath=
Looking up port of RPC 100003/2 on 164.130.129.16
Looking up port of RPC 100005/1 on 164.130.129.16
VFS: Mounted root (nfs filesystem) readonly.
Freeing unused kernel memory: 68k freed

Known limits

The netconsole support has been tested connecting the Linux PC host and the ST40 target at the same subnet.