My kexec test patches for OpenBMC

[Bruce Mitchell]

-----"openbmc" <openbmc-bounces+bruce.mitchell=ibm.com at lists.ozlabs.org> wrote: -----

>To: Bruce Mitchell <Bruce.Mitchell at ibm.com>
>From: Joel Stanley
>Sent by: "openbmc"
>Date: 02/24/2021 00:04
>Cc: Andrew Jeffery <andrew at aj.id.au>, OpenBMC Maillist
><openbmc at lists.ozlabs.org>
>Subject: [EXTERNAL] Re: My kexec test patches for OpenBMC
>
>On Fri, 19 Feb 2021 at 00:53, Bruce Mitchell
><Bruce.Mitchell at ibm.com> wrote:
>>
>> Hello Joel,
>>
>> Per your request yesterday, I am emailing the details of my
>kexec/kdump development efforts.
>
>Thanks. Here's what I tested:
>
>https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_sh
>enki_linux_commits_ast2600-2Dkexec&d=DwIFaQ&c=jf_iaSHvJObTbx-siA1Z
>Og&r=XYNAOU-BEndJr70kO1xkYnetCkaomJrlYQm5DudYzNc&m=oX_dPGCu4X3pBZl
>Dw0XYgu4z-3G1JebwP-IvlNbEMDE&s=gT3O534rB4ZDIPbf6Z78bKCR_op-JR1uYcv
>bd3z18RA&e=
>

Your kernel changes are similar to what I had done. Since you know
the community better than I do, I propose submitting your changes.
I can do the labor, but want you to get the credit. How would you
like me to proceed?

>>
>> I am running QEMU
>>
>> qemu-system-arm --version
>> QEMU emulator version 5.2.0 (v5.1.0-3479-g27ca38d3db)
>
>That looks fine. I'm using cedric's tree, but anything that will
>boot
>your kernel is fine.
>
>> qemu-system-arm -d cpu_reset -M tacoma-bmc -kernel
>/tmp/tmp.y2fpdAXM1h.kernel -dtb /tmp/tmp.BWkadwNbTf.dtb -initrd
>/tmp/tmp.jRpFbzfpBs.initrd -drive
>file=obmc-phosphor-image-witherspoon-tacoma.wic,if=sd,format=raw,i
>ndex=2 -net nic -net
>user,hostfwd=:127.0.0.1:2222-:22,hostfwd=:127.0.0.1:2443-:443,host
>name=qemu -nographic -append "crashkernel=64M
>console=ttyS4,115200n8 rootwait root=PARTLABEL=rofs-a"
>
>You could simplify your qemu setup if you want. Here's how I
>tested:
>
> $ qemu-system-arm -M tacoma-bmc -nographic -net nic -nic
>user,hostfwd=::2222-:22,tftp=/srv/tftp/ -kernel
>aspeed-g5-dev/arch/arm/boot/zImage -dtb
>aspeed-g5-dev/arch/arm/boot/dts/aspeed-bmc-opp-tacoma.dtb -initrd
>~/dev/kernels/misc/rootfs.cpio.xz
>
>This uses a small initramfs with the kexec utility, and has a copy
>of
>the kernel, initrd and dtb inside to make testing easy.
>
>Or, if you want, you can copy files into the system over the ssh
>port:
>
>I have this in my ~/.ssh/config:
>
>Host qemu
> Hostname localhost
> Port 2222
> User root
> UserKnownHostsFile /dev/null
> StrictHostKeyChecking no
>
>And then you can use scp like this:
>
>scp aspeed-g5-dev/arch/arm/boot/zImage
>aspeed-g5-dev/arch/arm/boot/dts/aspeed-bmc-opp-tacoma.dtb
>/home/joel/dev/kernels/misc/rootfs.cpio.xz qemu:
>
>> From OpenBMC within QEMU I am using the following to test kexec
>>
>> kexec -d -l /home/kexec_files/tmp.y2fpdAXM1h.kernel
>--initrd=/home/kexec_files/tmp.jRpFbzfpBs.initrd
>--dtb=/home/kexec_files/tmp.BWkadwNbTf.dtb --append="earlycon
>console=ttyS4,115200n8 rootwait root=PARTLABEL=rofs-a 1 maxcpus=1
>reset_devices"
>> kexec -d -e
>
>Here's how I was running it:
>
># kexec -l zImage --dtb aspeed-bmc-opp-tacoma.dtb --initrd
>rootfs.cpio.xz
># kexec -e
>
>I haven't set a new command line, so it uses the command line from
>the
>device tree (console=ttyS4,115200n8).
>
>With my patch we will not get the secondary CPU:
>
>[ 0.039517] ASPEED AST2600 rev A1 (05010303)
>[ 0.042030] smp: Bringing up secondary CPUs .
>[ 1.163950] CPU1: failed to come online
>[ 1.167999] smp: Brought up 1 node, 1 CPU
>[ 1.168164] SMP: Total of 1 processors activated (2250.00
>BogoMIPS).
>
>That should be the next step in working on the kexec patches. We
>want
>the secondary CPU to be in a state such that the new kernel can
>take
>control as it would in a firmware boot.
>
>Note that this didn't require any changes to the system beyond the
>kernel patch. I'm using the same defconfig as we have in the tree.
>
>Cheers,
>
>Joel
>
>

Hello Joel,

Thanks again for your advice and sharing your wisdom.
I am being urged by our manager to get this up-streamed
sooner rather than later. How can I best work with the
system to make this happen?

Thank you!

--
Bruce