I looked at the SGI project, but it wasn't suitable for our platform, as we didn't have the right sort of disk setup.
I ported the MCLX code to a 405-based platform. The code as originally distributed had a few bugs in it, but I don't think they ever fixed the bugs -- I fed changes back to them, and those changes may have made it to IBM. Or at least they told me IBM was interested in the project. If you do use their code, ignore the program that uncompresses the crash dumps -- as implemented, it's incredibly slow, and although that can be fixed, it's pointless, since crash can read the compressed dumps just fine (and can't read the uncompressed ones, just as a final irony). I don't have a complete list of the changes I needed to make, but here are a few: Makefile didn't specify compiling crash.c crash.c (machine-specific) specified "regs" instead of "gprs"; also specified tss.ksp instead of thread.ksp; also must #define PFN_PHYS() itself. The code in do_init_bootmem() is trying to work in bytes, not in frames. Anyway, once I got these various problems ironed out, plus a few in crash(1), the facility worked fine. The main problem you're apt to run into is having enough physical memory to run your system, hold the dump, and copy the dump from RAM into some file. NFS can be very useful here. The dump facility did prove to be quite useful and we did use it on live systems to track down problems. One thing to watch out for is diags that scrub memory, since they'll scrub out your dump, too. -- David Wright, InfiniSwitch Corp. > -----Original Message----- > From: Arun Dharankar [mailto:ADharankar at attbi.com] > Sent: Tuesday, April 08, 2003 11:58 AM > To: linuxppc-embedded at lists.linuxppc.org > Subject: Linux kernel panics and core dumps. > > > > Greetings. > > On x86 architectures there seem to be at least two ways of > producing Linux kernel panic dumps. These projects are > hosted at > > "http://lkcd.sourceforge.net/"; (originated in SGI), and > > "http://oss.missioncriticallinux.com/projects/mcore/"; > (originated in MCLX). > > > Of the two, the second one seems to work quite well on x86 > PCs. I dont know how much of it is actively supported on > PowerPCs. So, the first question is: > > Has anyone tried this on PowerPC, specifically Linux > kernel versions 2.4.x? The code for PowerPC seems to > be there, but the Makefiles dont seem to be up-to-date, > and could be broken. > > Further more, this same project has some documentation > which has a good discussion on different approaches to Linux > kernel memory dumps. One item in this discussion is about > the BIOS/bootloader support. > > > Essentially, if PPCBoot/U-Boot was to recognize the Linux > kernel memory layout, a much more reliable scheme could > be implemented. For example, under all panic or hang > conditions (watchdog), the system could just be rebooted. > During the startup, PPCBoot/U-Boot along with Linux, could > save the Linux kernel dump reliably. MCLX scheme seems > to follow this approach, but does not rely on the bootloader. > > Has anyone investigated this? Or anything already done, > and cares to share it? Any thoughts on this? > > > Best regards, > -Arun. > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
