OpenBMC console

The OpenBMC virtual serial console replaces IPMI Serial over LAN (SoL) as a way to see the UART output of your host system. Where you would have once run:

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Using /dev/mem on OpenBMC

OpenBMC’s kernel configuration disables /dev/mem by default. In the early days of the project some functionality was implemented using simple userspace programs that read and wrote straight to peripherals, instead of kernel drivers. Now that it has kernel drivers userspace access to memory is restricted.

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Linux kernel logs with GDB with Qemu

When your Linux kernel is misbehaving, you often look to the output of ‘dmesg’ to see what went wrong. If you can’t get to userspace, hopefully you have a serial port to see the latest output.

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Petitboot hacks

A safe way to try out a new petitboot release on your machine is to add it to your disk, and chainload from the in-flash version to the one on disk. This uses the same well-tested mechanim as booting your operating system, but doesn’t require touching flash. If something goes wrong, just reboot!

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Building Firefox for ppc64le

Firefox has bitrotted on PowerPC a little. I installed an Ubuntu 18.04 (and then upgraded to the in-development 18.10) ppc64le on a Power9 workstation, and attempted to run Firefox 61. It crashed (trimmed backtrace):

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Using QEMU to boot OpenBMC ASPEED kernel

The LTC team at IBM have created a useful model of the ASPEED BMC SoCs and upstreamed it to QEMU. If you’re on a recent distro, you can skip building it and sudo apt-get install qemu-system-arm instead.

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Jekyll container

This blog uses jekyll-now, which I found in a search for a method to have a simple blog. The highlight is it provides instructions for you to create and edit the blog using the Github interface.

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