Sang-Hoon RHEE rhee

tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

Getting started with Linux kernel development

Prerequisites

The Linux kernel is written in C, so you should have at least a basic understanding of C before diving into kernel work. You don't need expert level C knowledge, since you can always pick some things up underway, but it certainly helps to know the language and to have written some userspace C programs already.

It will also help to be a Linux user. If you have never used Linux before, it's probably a good idea to download a distro and get comfortable with it before you start doing kernel work.

Lastly, knowing git is not actually required, but can really help you (since you can dig through changelogs and search for information you'll need). At a minimum you should probably be able to clone the git repository to a local directory.

Foreward

This document was originally written several years ago. At the time I was working as an execution core verification engineer at Arm. The following points are coloured heavily by working in and around the execution cores of various processors. Apply a pinch of salt; points contain varying degrees of opinion.

It is still my opinion that RISC-V could be much better designed; though I will also say that if I was building a 32 or 64-bit CPU today I'd likely implement the architecture to benefit from the existing tooling.

Mostly based upon the RISC-V ISA spec v2.0. Some updates have been made for v2.2

Original Foreword: Some Opinion

The RISC-V ISA has pursued minimalism to a fault. There is a large emphasis on minimizing instruction count, normalizing encoding, etc. This pursuit of minimalism has resulted in false orthogonalities (such as reusing the same instruction for branches, calls and returns) and a requirement for superfluous instructions which impacts code density both in terms of size and

	## gen() function for proc.stdout ( run_commands, vdl_run )
	## async read from proc.stdout
	if True:
	def gen(proc):
	remains = b'' # remaining from prev read
	while proc.poll() is None:
	rlist, _, _ = select([proc.stdout],[],[],500)
	if proc.stdout not in rlist:
	continue
	data = os.read(proc.stdout.fileno(), 16384)

	#!/bin/sh -e

	OS=${OS:-`uname`}

	if [ "$OS" = 'Darwin' ]; then
	get_touch_time() {
	date -r ${unixtime} +'%Y%m%d%H%M.%S'
	}
	else
	# default Linux

	# Generate a new key
	openssl genrsa -out server.key 2048

	# Generate a new CSR
	openssl req -sha256 -new -key server.key -out server.csr

	# Check certificate against CA
	openssl verify -verbose -CApath ./CA/ -CAfile ./CA/cacert.pem cert.pem

	# Self Signed

	# coding: utf-8
	# download font from:
	# https://noto-website-2.storage.googleapis.com/pkgs/NotoSansCJKkr-hinted.zip
	from __future__ import print_function
	import sys
	import os
	import matplotlib as mpl
	import matplotlib.font_manager as fm

	try:

	## monitor GPU usage in jupyter notebook -- [email protected]
	## migrated to: https://gist.github.com/rhee-elten/1a1070e3a812ca863c3b937b5180b2f8