update cv

.github/workflows/build-jekyll.yml

@@ -1,33 +0,0 @@
-name: build and deploy jekyll
-
-on:
-  push:
-    branches:
-      - master
-
-jobs:
-  build_and_deploy:
-    runs-on: ubuntu-latest
-    steps:
-      - name: checkout
-        uses: actions/checkout@v3
-
-      - name: rubygems cache
-        uses: actions/cache@v3
-        with:
-          path: vendor/bundle
-          key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-gems-
-
-      - name: jekyll deploy
-        uses: "jeffreytse/jekyll-deploy-action@v0.4.0"
-        with:
-          provider: "github"
-          token: ${{ secrets.GITHUB_TOKEN }}
-          branch: "gh-pages"
-          jekyll_src: "./"
-          jekyll_cfg: "_config.yml"
-          cname: "jackbondpreston.me"
-          actor: "jackbondpreston"
-          pre_build_commands: "pacman -S --noconfirm libvips lcms2 openjpeg2 libpng libwebp libheif imagemagick openslide libjxl poppler-glib"

.github/workflows/main.yml

@@ -1,38 +0,0 @@
-# This is a basic workflow to help you get started with Actions
-
-name: cv-build
-
-# Controls when the workflow will run
-on:
-  # Triggers the workflow on push or pull request events but only for the "master" branch
-  push:
-    branches: [ "master" ]
-    paths: cv/**
-
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-# A workflow run is made up of one or more jobs that can run sequentially or in parallel
-jobs:
-  # This workflow contains a single job called "build"
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Set up Git repository
-        uses: actions/checkout@v2
-      - name: Compile LaTeX document
-        uses: xu-cheng/latex-action@v2
-        with:
-          working_directory: cv
-          root_file: main.tex
-      - name: Move built .pdf
-        run: |
-          mv cv/main.pdf ./cv.pdf
-      - name: Commit built .pdf
-        uses: EndBug/add-and-commit@v9
-        with:
-          add: 'cv.pdf'
-          author_name: 'Jack Bond-Preston'
-          author_email: 'jackbondpreston@outlook.com'
-          message: '[github action] update cv.pdf'
-          

.gitignore

@@ -1,2 +1,11 @@
-.jekyll-cache
-_site/
+public/
+static/processed_images/
+*.log
+cv/*.gz
+cv/*.xml
+*.aux
+*.bbl
+*.bcf
+*.blg
+*.out
+cv/*.pdf

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "syntaxes/console"]
+	path = syntaxes/console
+	url = https://github.com/haraldh/Sublime-console.git

CNAME

@@ -1 +0,0 @@
-jackbondpreston.me

Gemfile

@@ -1,7 +0,0 @@
-source "https://rubygems.org"
-
-gem 'jekyll', '~> 4.0'
-
-group :jekyll_plugins do
-    gem 'jekyll_picture_tag', '~> 2.0'
-  end

Gemfile.lock

@@ -1,84 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    addressable (2.8.1)
-      public_suffix (>= 2.0.2, < 6.0)
-    colorator (1.1.0)
-    concurrent-ruby (1.1.10)
-    em-websocket (0.5.3)
-      eventmachine (>= 0.12.9)
-      http_parser.rb (~> 0)
-    eventmachine (1.2.7)
-    ffi (1.15.5)
-    forwardable-extended (2.6.0)
-    http_parser.rb (0.8.0)
-    i18n (1.12.0)
-      concurrent-ruby (~> 1.0)
-    jekyll (4.3.1)
-      addressable (~> 2.4)
-      colorator (~> 1.0)
-      em-websocket (~> 0.5)
-      i18n (~> 1.0)
-      jekyll-sass-converter (>= 2.0, < 4.0)
-      jekyll-watch (~> 2.0)
-      kramdown (~> 2.3, >= 2.3.1)
-      kramdown-parser-gfm (~> 1.0)
-      liquid (~> 4.0)
-      mercenary (>= 0.3.6, < 0.5)
-      pathutil (~> 0.9)
-      rouge (>= 3.0, < 5.0)
-      safe_yaml (~> 1.0)
-      terminal-table (>= 1.8, < 4.0)
-      webrick (~> 1.7)
-    jekyll-sass-converter (2.2.0)
-      sassc (> 2.0.1, < 3.0)
-    jekyll-watch (2.2.1)
-      listen (~> 3.0)
-    jekyll_picture_tag (2.0.4)
-      addressable (~> 2.6)
-      jekyll (~> 4.0)
-      mime-types (~> 3.0)
-      objective_elements (~> 1.1)
-      rainbow (~> 3.0)
-      ruby-vips (~> 2.0.17)
-    kramdown (2.4.0)
-      rexml
-    kramdown-parser-gfm (1.1.0)
-      kramdown (~> 2.0)
-    liquid (4.0.3)
-    listen (3.7.1)
-      rb-fsevent (~> 0.10, >= 0.10.3)
-      rb-inotify (~> 0.9, >= 0.9.10)
-    mercenary (0.4.0)
-    mime-types (3.4.1)
-      mime-types-data (~> 3.2015)
-    mime-types-data (3.2022.0105)
-    objective_elements (1.1.2)
-    pathutil (0.16.2)
-      forwardable-extended (~> 2.6)
-    public_suffix (5.0.0)
-    rainbow (3.1.1)
-    rb-fsevent (0.11.2)
-    rb-inotify (0.10.1)
-      ffi (~> 1.0)
-    rexml (3.2.5)
-    rouge (4.0.0)
-    ruby-vips (2.0.17)
-      ffi (~> 1.9)
-    safe_yaml (1.0.5)
-    sassc (2.4.0)
-      ffi (~> 1.9)
-    terminal-table (3.0.2)
-      unicode-display_width (>= 1.1.1, < 3)
-    unicode-display_width (2.3.0)
-    webrick (1.7.0)
-
-PLATFORMS
-  x86_64-linux
-
-DEPENDENCIES
-  jekyll (~> 4.0)
-  jekyll_picture_tag (~> 2.0)
-
-BUNDLED WITH
-   2.3.26

README.md

@@ -1 +0,0 @@
-# website

_config.yml

@@ -1,10 +0,0 @@
-url: "https://jackbondpreston.me" # the base hostname & protocol for your site, e.g. http://example.com
-baseurl: "" # the subpath of your site, e.g. /blog
-title: "jack bond-preston" # the name of your site, e.g. ACME Corp.
-
-show_dir_listing: true
-
-safe: false
-
-picture:
-  source: "pictures/"

_layouts/default.html

@@ -1,26 +0,0 @@
-<!DOCTYPE html>
-
-<!--
-
-	　 ／l、
-	ﾞ（ﾟ､ ｡ ７
-	　l、ﾞ ~ヽ
-	　じしf_, )ノ
-
--->
-
-<html lang="{{ site.lang | default: " en-US" }}">
-
-<head>
-  <meta name="viewport" content="width=device-width, initial-scale=1">
-  <meta charset="utf-8">
-  <title>{{ page.title }} - {{ site.title }}</title>
-  <link rel="stylesheet" href="{{ '/assets/css/main.css' | relative_url }}">
-  <link rel="stylesheet" href="{{ '/assets/css/pygments.css' | relative_url }}">
-</head>
-
-<body>
-  {{ content }}
-</body>
-
-</html>

_layouts/post-sensor-watch.html

@@ -1,212 +0,0 @@
-<!DOCTYPE html>
-
-<!--
-
-	　 ／l、
-	ﾞ（ﾟ､ ｡ ７
-	　l、ﾞ ~ヽ
-	　じしf_, )ノ
-
--->
-
-<html lang="{{ site.lang | default: " en-US" }}">
-
-<head>
-    <meta name="viewport" content="width=device-width, initial-scale=1">
-    <meta charset="utf-8">
-    <title>{{ page.title }} - {{ site.title }}</title>
-    <link rel="stylesheet" href="{{ '/assets/css/main.css' | relative_url }}">
-    <style>
-        body {
-            padding: 0;
-            margin: 0;
-            min-height: 100vh;
-        }
-
-        .wrapper {
-            display: grid;
-            grid-template-columns: 30rem auto;
-            grid-template-rows: auto;
-            gap: 0;
-            min-height: 100vh;
-        }
-
-        .article {
-            padding: 5rem;
-            padding-bottom: 1rem;
-        }
-
-        .side {
-            background-image: url(/assets/images/sensor-watch/f91w-strap.svg);
-            background-repeat: repeat-y;
-        }
-
-        .side>svg {
-            width: 30rem;
-            position: fixed;
-        }
-
-        @media only screen and (max-width: 1500px) {
-            .wrapper {
-                grid-template-columns: 10rem auto;
-                grid-template-rows: auto;
-            }
-
-            .side>svg {
-                width: 10rem;
-            }
-
-            .article {
-                padding-left: 3rem;
-                padding-right: 1rem;
-                padding-top: 1rem;
-            }
-        }
-
-        @media only screen and (max-width: 800px) {
-            .side {
-                display: none;
-            }
-
-            .wrapper {
-                grid-template-columns: auto;
-                grid-template-rows: auto;
-            }
-
-            .article {
-                padding: 1rem;
-            }
-        }
-    </style>
-</head>
-
-<body>
-    <div class="wrapper">
-        <div class="side">
-            <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 300 500">
-                <defs>
-                    <style>
-                        .cls-1 {
-                            fill: #0c1113;
-                        }
-
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-                            fill: none;
-                            stroke: #f6b4c1;
-                            stroke-miterlimit: 10;
-                            stroke-width: 2px;
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-                    <line class="cls-2" x1="234" y1="389.42" x2="234" y2="500" />
-                    <polyline class="cls-2" points="150 389.42 236.56 389.42 244.33 362.67" />
-                </g>
-            </svg>
-        </div>
-        <div class="article">
-            <h1><a href="{{ page.url }}">{{ page.title }}</a></h1>
-
-            {{ content }}
-
-            <hr>
-
-            <p><a href="mailto:jackbondpreston@outlook.com">email me</a> to have a conversation</p>
-        </div>
-    </div>
-</body>

_layouts/post.html

@@ -1,13 +0,0 @@
----
-layout: default
----
-
-<div class="article">
-    <h1><a href="{{ page.url }}">{{ page.title }}</a></h1>
-
-    {{ content }}
-
-    <hr>
-
-    <p><a href="mailto:jackbondpreston@outlook.com">email me</a> to have a conversation</p>
-</div>

_plugins/header.rb

@@ -1,6 +0,0 @@
-# https://stackoverflow.com/a/53893197/
-class Jekyll::MarkdownHeader < Jekyll::Converters::Markdown
-    def convert(content)
-      super.gsub(/<h(2) id="(.*?)">(.*)<\/h(\d)>/, '<h\1 id="\2">\3<a href="#\2" class="header-link">[<img src="/assets/images/link.svg" />]</a></h\1>')
-    end
-  end

_sass/main.scss

@@ -1,122 +0,0 @@
-$background-color: rgb(12, 17, 20);
-$body-color: rgb(252, 252, 252);
-$heading-color: rgb(255, 182, 193);
-$link-color: rgb(252, 169, 184);
-$inl-code-color: rgb(165, 214, 255);
-
-@font-face {
-  font-family: 'Source Code Pro';
-  font-style: normal;
-  font-weight: 400;
-  src: local(''),
-       url('../fonts/source-code-pro-v22-latin-ext_latin-regular.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
-       url('../fonts/source-code-pro-v22-latin-ext_latin-regular.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
-}
-
-@font-face {
-  font-family: 'Source Code Pro';
-  font-style: normal;
-  font-weight: 700;
-  src: local(''),
-       url('../fonts/source-code-pro-v22-latin-ext_latin-700.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
-       url('../fonts/source-code-pro-v22-latin-ext_latin-700.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
-}
-
-@font-face {
-  font-family: 'Source Code Pro';
-  font-style: italic;
-  font-weight: 400;
-  src: local(''),
-       url('../fonts/source-code-pro-v22-latin-ext_latin-italic.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
-       url('../fonts/source-code-pro-v22-latin-ext_latin-italic.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
-}
-
-@font-face {
-  font-family: 'Source Code Pro';
-  font-style: italic;
-  font-weight: 700;
-  src: local(''),
-       url('../fonts/source-code-pro-v22-latin-ext_latin-700italic.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
-       url('../fonts/source-code-pro-v22-latin-ext_latin-700italic.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
-}
-
-body {
-  background-color: $background-color;
-  color: $body-color;
-  padding-left: 5vw;
-  padding-right: 5vw;
-  padding-top: 5vh;
-  font-family: 'Source Code Pro';
-  font-size: 1.5rem;
-
-  @media screen and (max-width: 600px) {
-    font-size: 1rem;
-  }
-}
-
-h1 {
-  color: $heading-color;
-  margin: 0;
-}
-
-h2 {
-  margin: 0;
-  margin-top: 3rem;
-  margin-bottom: 0.5rem;
-}
-
-a {
-  color: $link-color;
-  font-weight: bold;
-  text-decoration: none;
-}
-
-li {
-  line-height: 150%;
-}
-
-.article {
-  p, li {
-    a {
-      font-weight: normal;
-      text-decoration: underline;
-      word-wrap: break-word;
-    }
-
-    code {
-      color: #a5d6ff;
-    }
-  }
-
-  picture img, p img {
-    max-width: 100%;
-    display: block;
-  }
-
-  code, pre {
-    font-family: 'Source Code Pro';
-    margin: 0;
-    padding: 0;
-  }
-
-  .header-link {
-    display: inline-block;
-  }
-}
-
-table {
-  border-spacing: 0;
-}
-
-h2 .header-link {
-  display: none;
-
-  padding-left: 10px;
-  font-weight: normal;
-  font-size: 1.3rem;
-
-  img {
-    height: 1.25rem;
-    margin-bottom: -4px;
-  }
-}

assets/css/main.scss

@@ -1,4 +0,0 @@
----
----
-
-@import "main";

assets/css/pygments.css

@@ -1,447 +0,0 @@
-pre {
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-    margin-top: 0;
-    vertical-align: top;
-}
-
-figure.highlight {
-    margin: 0;
-    margin-left: 1.5rem;
-    display: block;
-    overflow-x: auto;
-}
-
-@media screen and (max-width: 600px) {
-    pre {
-        font-size: 0.8rem;
-    }
-}
-
-td.gutter {
-    padding-right: 10px;
-    border-right: 3px solid rgb(252, 169, 184);
-    border-radius: 3px;
-}
-
-td.code {
-    padding-left: 15px;
-}
-
-body .hll {
-    background-color: #6e7681
-}
-
-body .c {
-    color: #8b949e;
-    font-style: italic
-}
-
-/* Comment */
-body .err {
-    color: #f85149
-}
-
-/* Error */
-body .esc {
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-    color: #c9d1d9;
-    text-decoration: underline
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-
-/* Generic.Underline */
-body .kc {
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-/* Keyword.Constant */
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code/cheri/Makefile

@@ -1,5 +1,5 @@
-CFLAGS += -Wall -g -fno-stack-protector
-CC ?= clang
+CFLAGS += -Wall -g -fno-stack-protector -O0
+CC := clang
 PURECAP_CC ?= ~/cheri/output/sdk/utils/cheribsd-riscv64-purecap-clang
 
 SOURCES := $(wildcard *.c)

code/cheri/ptrs_as_numbers.c

@@ -2,20 +2,21 @@
 
 int main() {
     int magic = 9999;
-    (void)magic;
+    (void)magic; // suppress unused warning
+
     int arr[] = { 1234, 5678 };
 
     int *x = &(arr[0]); // x is a pointer to first element of arr
-    printf("*x=%d\n", *x);
+    printf("*(%lx)=%d\n", (size_t) x, *x);
 
     unsigned long x_addr = (size_t) x; // we're going to assume size_t = unsigned long here
     x_addr += 4; // sizeof(int) == 4
     x = (int *) x_addr;
-    printf("*x=%d\n", *x);
+    printf("*(%lx)=%d\n", (size_t) x, *x);
 
     x_addr += 4;
     x = (int *) x_addr;
-    printf("*x=%d\n", *x);
+    printf("*(%lx)=%d\n", (size_t) x, *x);
 
     return 0;
 }

code/cheri/ptrtypes.c

@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdint.h>
+
+int main() {
+    printf("type          size (hex)   size (dec)\n");
+    printf("=====================================\n");
+#ifdef __PTRADDR_TYPE__
+    printf("ptraddr_t     0x%.2lx         %.2lu\n", sizeof(ptraddr_t), sizeof(ptraddr_t));
+#endif
+    printf("uintptr_t     0x%.2lx         %.2lu\n", sizeof(uintptr_t), sizeof(uintptr_t));
+    printf("size_t        0x%.2lx         %.2lu\n", sizeof(size_t), sizeof(size_t));
+    printf("void*         0x%.2lx         %.2lu\n", sizeof(void*), sizeof(void*));
+    printf("=====================================\n");
+
+#ifdef __CHERI__
+    int x = 111;
+    int y[] = { 888, 999 };
+
+    int *a = &x;
+    int *b = &(y[0]);
+
+    // transplant address from capability a to capability b
+    printf("*b: %d\n", *b);
+    ptraddr_t a_addr = __builtin_cheri_address_get(a);
+    b = __builtin_cheri_address_set(a, a_addr);
+    printf("*b: %d\n", *b);
+
+    b = &(y[0]);
+    // uintptr_t is an unsigned integer type that preserves capabilities
+    uintptr_t b_uintptr = (uintptr_t) b;
+    b_uintptr += sizeof(int);
+    b = (int*) b_uintptr;
+    printf("*b: %d\n", *b);
+#endif
+
+    return 0;
+}

config.toml

@@ -0,0 +1,14 @@
+base_url = "https://jackbondpreston.me"
+compile_sass = true
+build_search_index = false
+
+generate_feeds = true
+
+[markdown]
+highlight_code = true
+extra_syntaxes_and_themes = ["syntaxes/console/Sublime-console/"]
+
+[slugify]
+anchors = "on"
+
+[extra]

content/_index.md

@@ -0,0 +1,27 @@
++++
+title = "home"
+sort_by = "date"
+template = "index.html"
+page_template = "article.html"
+insert_anchor_links = "right"
++++
+
+# jack bond-preston
+
+## contact
+you can contact me via [email](mailto:jackbondpreston@outlook.com) or on [linkedin](https://www.linkedin.com/in/jack-bond-preston-922706150/)
+
+my cv is available for viewing [here](cv.pdf)
+
+## open source
+
+some of my personal repositories are available [here](https://git.jackbondpreston.me)
+
+my merged [dpdk](https://www.dpdk.org/) work can be found on [the project's repository](https://git.dpdk.org/dpdk/log/?qt=author&q=jack.bond-preston%40foss.arm.com)
+
+my public [onload](https://www.xilinx.com/products/boards-and-kits/x2-series/onload.html) commits at amd can be found on [the github repo](https://github.com/Xilinx-CNS/onload)
+
+some of my work at arm on [morello](https://www.arm.com/architecture/cpu/morello) is available on the [morello musl gitlab](https://git.morello-project.org/morello/musl-libc/-/commits/morello/master?author=Jack%20Bond-Preston) 
+
+
+<h2>articles<a href="/atom.xml" class="atom-link">[atom feed]</a></h2>

content/cheri.md

@@ -1,50 +1,58 @@
----
-layout: post
-title: "CHERI"
----
++++
+title = "CHERI"
+date = 2022-11-19
++++
 
 ## preamble
 [CHERI](https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/) is an acronym for Capability Hardware Enhanced RISC Instructions. it is a security-focussed project aimed at improving memory protection at the hardware level. the project is complex and it has many potential applications.
 
-in this article I will go into some basics to give an understanding behind some changes that CHERI makes to how programs execute and are written. this will be focussed almost entirely in C, as this is where my experience lies - it is also where some of the effects of CHERI are most easily felt.this article is going to be a _very simplistic_ introduction to CHERI, and I'm going to attempt to explain the basics behind everything I cover. a basic understanding of C will be beneficial.
+in this article I will go into some basics to give an understanding behind some changes that CHERI makes to how programs execute and are written. this will be focussed almost entirely in C, as this is where my experience lies - it is also where some of the effects of CHERI are most easily felt.this article is going to be a _very simplistic_ introduction to CHERI, and I'm going to attempt to explain the basics behind everything I cover. a basic understanding of C will be necessary.
 
 ***note:*** [the Morello platform](https://www.arm.com/architecture/cpu/morello) is an evaluation board produced by [Arm](https://www.arm.com/) to provide a physical implementation of CHERI extending [the Arm AArch64 ISA](https://en.wikipedia.org/wiki/AArch64). I previously worked on this platform at Arm, [porting the musl C library to Morello](https://git.morello-project.org/morello/musl-libc/). implementations for CHERI that are worth looking into from a more open perspective <a href="https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-951.pdf"> are the MIPS (chapter 4) and RISC-V (chapter 5) ones</a>. Morello is the only implementation that exists in a true hard core format, afaik - but this is obviously hard to obtain so you'll just be playing around with emulators/models anyway.
 
 
 ## memory safety bugs
-to first understand how CHERI tries to fix some simple issues, let's first look at some simplified examples of issues that arise when we aren't using a CHERI-based architecture. 
+to understand how CHERI tries to fix some simple issues, we'll first look at some simplified examples of issues that arise when we aren't using a CHERI-based architecture. 
 
 
 ### a simple memory safety bug
 let's take a look at this C code:
 
-{% highlight c linenos %}
-{% include_relative code/membug.c %}
-{% endhighlight %}
+{{ code(path="cheri/membug.c", syntax="c", linenos=true) }}
 
-now let's try using our new program:
+and try running the compiled output of said program:
 
-{% highlight console %}
+```console
 $ ./membug
 enter your name: jack
 hello jack
 my_perfect_string: what a beautiful string
-{% endhighlight %}
+```
 
-works on my machine boss! code review +1, and merged... until our good friend <a href="https://en.wikipedia.org/wiki/Hubert_Blaine_Wolfeschlegelsteinhausenbergerdorff_Sr.">Hubert Blaine Wolfeschlegelsteinhausenbergerdorff Sr.</a> comes along. he emails me a strangeerror he's seen:
+works on my machine boss! code review +1, and merged... 
 
-{% highlight console %}
+...until our good friend [Hubert Blaine Wolfeschlegelsteinhausenbergerdorff Sr.](https://en.wikipedia.org/wiki/Hubert_Blaine_Wolfeschlegelsteinhausenbergerdorff_Sr.) comes along. he emails me a strange error he's running into:
+
+```console
 $ ./membug
 enter your name: Hubert Blaine Wolfeschlegelsteinhausenbergerdorff Sr.
 hello Hubert Blaine Wolfeschlegelsteinhausenbergerdorff Sr.
 my_perfect_string: hausenbergerdorff Sr.
-{% endhighlight %}
+```
 
-that's not supposed to happen! his name has spilled over into our `my_perfect_string[]` array! turns out our issue is that when we use `fgets()`, we've set the second parameter, `size`, to `1000` - but our `user_name[32]` array c1593an only fit 32 characters (and the last of these should be a null terminator, so 31 usable characters).
+***note:*** if you compile and run this on your machine, you may not get the same output. that's because we're invoking *undefined behaviour* here, so the compiler can kind of do whatever it wants. I'll always provide the output that demonstrates what I'm trying to show when giving examples like this. for what it's worth, I'm running `clang 10.0.0-4ubuntu1` with target `x86_64-pc-linux-gnu`. compilation options, the `Makefile`, and such are available [code subdirectory of this article's source](https://github.com/jackbondpreston/jackbondpreston.github.io/tree/master/_posts/cheri/code).
 
-`fgets` fills up `user_name`, but it hasn't finished with the name yet! it doesn't care (or know) that `user_name` is full, it's just going to keep going until it finishes our user input, or reads 999 characters from standard input. and thus it keeps mindlessly writing, overwriting the memory we've used to store our precious perfect string (which happens to be immediately after `user_name`). let's take a look at the stack in GDB to see why this happens:
+that's not supposed to happen! his name has spilled over into our `my_perfect_string[]` array! turns out our issue is that when we use `fgets(char *str, int count, FILE *stream)`, we've set the second parameter (`size`) to `1000` - but our `user_name[32]` array can only fit 32 characters (and the last of these should be a null terminator, so 31 usable characters).
 
-{% highlight plaintext %}
+`fgets()` fills up `user_name`, but it hasn't finished with the name yet! it doesn't care (or know) that `user_name` is full, it's just going to keep going until it finishes our user input, or reads 999 characters from standard input. thus it keeps mindlessly writing, overwriting the section memory we've used to store our precious perfect string (which happens to be immediately after `user_name`). 
+
+***note:*** `fgets()` has a cousin, `gets(char *s)`, which is particularly poor with regards to memory safety (due to lack of `size` parameter), [and has largely been moved away from in modern C](https://linux.die.net/man/3/fgets):
+> LSB deprecates `gets()`. POSIX.1-2008 marks `gets()` obsolescent. ISO C11 removes the specification of `gets()` from the C language, and since version 2.16, glibc header files don't expose the function declaration if the `_ISOC11_SOURCE` feature test macro is defined.
+
+let's take a look at the stack in GDB to see how this happens:
+
+
+```gdb
 (gdb) b memdebug.c:7 
 (gdb) run 
 Breakpoint 1, main () at membug.c:7
@@ -61,59 +69,61 @@ Breakpoint 1, main () at membug.c:7
 0x7fffffffdc10: 119 'w'     104 'h'     97  'a'     116 't'     32  ' '     97  'a'     32  ' '     98  'b'
 0x7fffffffdc18: 101 'e'     97  'a'     117 'u'     116 't'     105 'i'     102 'f'     117 'u'     108 'l'
 0x7fffffffdc20: 32  ' '     115 's'     116 't'     114 'r'     105 'i'     110 'n'     103 'g'     0   '\000'
-{% endhighlight %}
+```
 
 we can see our two character arrays are right next to each other on the stack (`user_name` contains some gibberish as it is not zero-initialised).
 
-***note:*** this code was compiled with `-fno-stack-protector` to reproduce this behaviour. compilers have certain techniques like this which can help protect against such attacks, but there are often ways around these by using less primitive attacks.
+***note:*** this code was compiled with `-fno-stack-protector` to reproduce this behaviour. compilers have certain techniques which can help protect against such attacks, but there are often ways around these by using less primitive attacks. we are just ignoring these in this article for simplicity.
 
-okay, it's a pretty easy fix, we just need to change the `fgets(char *s, int size, FILE *stream)` parameter `size` to `32`.
+okay, at least it's a pretty easy fix: we just need to change the `fgets()` parameter `size` to `32`.
 
-***note:*** you may initially think "why not 31? don't we need to save a character for the null byte at the end?". thankfully, `fgets` does this for us. excerpt from `man fgets`: 
+***note:*** you may initially think "why not `31`? don't we need to save a character for the null byte at the end?". thankfully, `fgets` does this for us. excerpt from `man fgets`: 
 
-> "fgets() reads in _at most one less than size_ characters from stream and stores them into the buffer pointed to by s [...] A terminating null byte ('\0') is stored after the last character in the buffer". 
+> `"fgets() reads in _at most one less than size_ characters from stream and stores them into the buffer pointed to by s [...] A terminating null byte ('\0') is stored after the last character in the buffer".`    
 
 this is a good question to be asking though, being careful is key when it comes to these kinds of things.
 
 
 ### why hardware?
-okay, so that's an easy fix. why are we talking about doing anything in hardware here? just write the code correctly! the issue is code gets very complex, and this is a very simplistic situation. some memory safety bugs can be incredibly complicated and go unnoticed for decades. the C language especially gives the programmer many, many opportunities to make mistakes - and it only takes one to be a problem. a lot of the software we are using these days is based on stacks upon stacks of software written in different languages, and there are going to be bugs in there. CHERI should give us some protection "for free" (it's not this simple, in actuality).
+okay, that wasn't too bad. why are we talking about doing anything in hardware here? just write the code correctly! 
 
-some languages (e.g. Rust) are going to offer you strong memory safety guarantees at compile-time, but that's not the topic of this article. the differences between doing this kind of protection in software or hardware (or both) is more complex than the scope of this article. in addition, CHERI's benefits are more wide in breadth than just protecting against this kind of issue.
+we've looked at a very simplistic situation, with no real stakes and nothing to exploit (and an unrealistically simple bug). if this bug was exploitable for malicious gain, it could already be too late by the time we found it.
+
+memory safety problems make up the vast majority of problematic security issues. the Chromium project [found 70% of its serious security bugs were memory safety related](https://www.chromium.org/Home/chromium-security/memory-safety/) and [Microsoft found the same prevalence](https://msrc-blog.microsoft.com/2019/07/16/a-proactive-approach-to-more-secure-code/). some memory safety bugs can be incredibly complicated and go unnoticed for decades. the C language especially gives the programmer many, many opportunities to make mistakes - and it only takes one to be a problem. a lot of the software we are using these days is based on layers upon layers of software written in different languages, and there are going to be bugs in there. CHERI aims to give us some protection at a hardware level.
+
+***Note:*** some languages (e.g. Rust) are going to offer you strong memory safety guarantees at compile-time, but I'm not going to include the discussions around this and how it compares to CHERI in this article. this article will focussed on how CHERI applies to C (and to some extent, C++ by extension).
 
 
 ## pointers recap
 let's quickly recap a basic idea of what a pointer is. we're going to ignore things like [virtual memory](https://en.wikipedia.org/wiki/Virtual_memory) for brevity. we can think of a pointer in a normal 64-bit architecture (e.g. AArch64) simply as a 64-bit unsigned value that holds the memory address of something we care about. this is a simplification (as are most things), but it can help us reason about the general idea:
 
-{% highlight c %}
+```c
 int val = 1593;
 int *x = &val; // x points to val
-{% endhighlight %}
+```
 
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1920 314"><defs><style>.prefix__prefix__d{fill:none;stroke-miterlimit:10}.prefix__prefix__f,.prefix__prefix__h,.prefix__prefix__i{font-size:24px}.prefix__prefix__f,.prefix__prefix__h,.prefix__prefix__k{fill:#fcfcfc}.prefix__prefix__f,.prefix__prefix__l{font-family:Source Code Pro}.prefix__prefix__d{stroke:gray;stroke-width:4px}.prefix__prefix__h,.prefix__prefix__m{font-family:Source Code Pro;font-weight:700}.prefix__prefix__i{fill:gray}</style></defs><g id="prefix__prefix__a"><path fill="#0c1114" d="M0 0h1920v314H0z"/><text class="prefix__prefix__h" transform="translate(577.46 133.41)"><tspan x="0" y="0">int *x</tspan></text><text class="prefix__prefix__f" transform="translate(490.97 177.1)"><tspan x="0" y="0">0x0000010000000004</tspan></text><path d="M481.16 206v18.5M760.5 206v18.5m-279 0h279" stroke="#fcfcfc" fill="none" stroke-miterlimit="10" stroke-linecap="square" stroke-width="3"/><text transform="translate(578.78 241.33)" font-size="20" font-family="Source Code Pro" fill="#fcfcfc"><tspan x="0" y="0">address</tspan></text><path stroke-width="4" stroke="#fcfcfc" fill="none" stroke-miterlimit="10" d="M752 171h204.56"/><path class="prefix__prefix__k" d="M948.64 182.62L992 171.01l-43.36-11.63v23.24z"/><text transform="translate(1272.76 177.16)" fill="#fcfcfc" font-size="24"><tspan class="prefix__prefix__m" x="0" y="0">mem[</tspan><tspan class="prefix__prefix__l" x="57.6" y="0">0x0000010000000004</tspan><tspan class="prefix__prefix__m" x="316.79" y="0">]</tspan></text><text class="prefix__prefix__i" transform="translate(1272.76 133.16)"><tspan class="prefix__prefix__m" x="0" y="0">mem[</tspan><tspan class="prefix__prefix__l" x="57.6" y="0">0x0000010000000000</tspan><tspan class="prefix__prefix__m" x="316.79" y="0">]</tspan></text><text class="prefix__prefix__i" transform="translate(1271.76 224.16)"><tspan class="prefix__prefix__m" x="0" y="0">mem[</tspan><tspan class="prefix__prefix__l" x="57.6" y="0">0x0000010000000008</tspan><tspan class="prefix__prefix__m" x="316.79" y="0">]</tspan></text></g><g id="prefix__prefix__b"><path class="prefix__prefix__d" d="M1260 58v48H985V58"/><path d="M1258 195v40H987v-40h271m4-4H983v48h279v-48zm-4-84v40H987v-40h271m4-4H983v48h279v-48z" fill="gray"/><path class="prefix__prefix__k" d="M756.16 150.93v40h-271v-40h271m4-4h-279v48h279v-48zM1258 151v40H987v-40h271m4-4H983v48h279v-48z"/><text class="prefix__prefix__f" transform="translate(1094 177.09)"><tspan x="0" y="0">1593</tspan></text><text class="prefix__prefix__h" transform="translate(1007.6 45.16)"><tspan x="0" y="0">memory (as ints)</tspan></text><path class="prefix__prefix__d" d="M1260 284v-48H985v48"/></g></svg>
 
 and on these normal architectures, this pointer generally is just a number. we can do weird things with it, treating it as a number...
 
-{% highlight c linenos %}
-{% include_relative code/ptrs_as_numbers.c %}
-{% endhighlight %}
+{{ code(path="cheri/ptrs_as_numbers.c", syntax="c", linenos=true) }}
 
 ...and this code will often still work:
 
-{% highlight console %}
+```console
 $ ./ptrs_as_numbers
-*x=1234
-*x=5678
-*x=9999
-{% endhighlight %}
+*(7fff98640c20)=1234
+*(7fff98640c24)=5678
+*(7fff98640c28)=9999
+```
 
-yikes! now, when you start messing with pointers like this, you're bound to run into a bunch of undefined behaviour. but C programmers write undefined behaviour all the time, and my computer executes this program fine without complaining at all. doesn't it feel a bit weird that we can take a pointer to `arr[0]` and modify it to load `secret`? they're not even part of the same array...
+yikes! now, when you start messing with pointers like this, you're bound to run into a bunch of undefined behaviour. but C programmers write undefined behaviour all the time (and not always by accident), and my computer executes this program fine without complaining at all. doesn't it feel a bit weird that we can take a pointer to `arr[0]` and modify it to load `magic`? they're not even part of the same array...
 
 
 ## introducting capabilities
-CHERI introduces capabilities, which can be thought of as an extension to pointers. they still store an address of something we care about, but they have extra information too! in a 64-bit system, a pointer would typically be a 64-bit value (as dicussed previously). the corresponding capability in a CHERI platform is 128 bits (or 129 bits if you look at it a certain way, more about that later...).
+CHERI introduces capabilities, which can be thought of as an extension to pointers. they still store an address of something we care about, but they have extra information too! in a 64-bit system, a pointer would typically be a 64-bit value (as dicussed previously). the corresponding capability in a CHERI platform is 128 bits (or 129 bits if you look at it a certain way, more about that later).
 
-as you might have guessed, this "extra information" takes up 64 bits of the capability. bits are assigned to three key pieces of metadata: *bounds*, *permissions*, and *object type*. there is also an additional 1-bit _tag_ which is stored out-of-band: it is not a 129-bit value - instead each 128-bit capability can be thought of as being associated with a 1-bit validity tag. the architecture manages this. the diagram below is provided as a rough overview of this. note that it is not to scale.
+as you might have guessed, this "extra information" takes up extra bits of the capability (how much is actually a little complicated - we will touch on that). bits are assigned to three key pieces of metadata: *bounds*, *permissions*, and *object type*. there is also an additional 1-bit _tag_ which is stored out-of-band: it is not a 129-bit value - instead each 128-bit capability can be thought of as being associated with a 1-bit validity tag. the architecture manages this association for us. the diagram below is provided as a rough overview of this. note that it is not to scale.
 
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1920 314"><defs><style>.prefix__c{fill:none;stroke:#fcfcfc;stroke-linecap:square;stroke-miterlimit:10;stroke-width:3px}.prefix__f,.prefix__g{fill:#fcfcfc}.prefix__f{font-family:Source Code Pro;font-size:20px}</style></defs><g id="prefix__a"><path fill="#0c1114" d="M0 0h1920v314H0z"/><text transform="translate(101.86 232.41)" font-family="Source Code Pro" font-weight="700" fill="#fcfcfc" font-size="24"><tspan x="0" y="0">int *x (capability)</tspan></text><text transform="translate(1205.97 232.1)" font-family="Source Code Pro" fill="#fcfcfc" font-size="24"><tspan x="0" y="0">0x0000010000000004</tspan></text><path class="prefix__c" d="M1016 261v18.5M1656 261v18.5M1016 279.5h640"/><text class="prefix__f" transform="translate(1293.78 296.33)"><tspan x="0" y="0">address</tspan></text><path class="prefix__c" d="M700 191.5V173M1020 191.5V173M700 173h320"/><text class="prefix__f" transform="translate(823.78 167.74)"><tspan x="0" y="0">bounds</tspan></text><path class="prefix__c" d="M554 260.34v18.5M704 260.34v18.5M554 278.84h150"/><text class="prefix__f" transform="translate(562.78 295.68)"><tspan x="0" y="0">object type</tspan></text><g><path class="prefix__c" d="M391.89 191.56v-18.5M541.89 191.56v-18.5M391.89 173.06h150"/></g><text class="prefix__f" transform="translate(400.67 167.8)"><tspan x="0" y="0">permissions</tspan></text><text class="prefix__f" transform="translate(304.67 31.07)"><tspan x="0" y="0">tag (out-of-band)</tspan></text><g><path class="prefix__c" d="M391.33 55.92v-18.5M421.33 55.92v-18.5M391.33 37.42h30"/></g></g><g id="prefix__b"><path class="prefix__g" d="M1651.66 205.93v40h-632v-40h632m4-4h-640v48h640v-48z"/><path class="prefix__g" d="M1016 206v40H704v-40h312m4-4H700v48h320v-48z"/><path class="prefix__g" d="M700 206v40H558v-40h142m4-4H554v48h150v-48z"/><path class="prefix__g" d="M554 206v40h-12v-40h12m4-4h-20v48h20v-48z"/><path class="prefix__g" d="M538 206v40H396v-40h142m4-4H392v48h150v-48zM418.5 70v40h-22V70h22m4-4h-30v48h30V66z"/></g></svg>
 
@@ -123,13 +133,13 @@ I am mostly going to focus on _bounds_ in this article, as it is not too difficu
 
 can you imagine how we can use bounds to prevent our previous memory safety bug from occurring? the key is that we can set the bounds on the capability pointing to `user_name` which we pass to `fgets`, such that the capability may only access the contents of the array. this means that when `fgets` tries to write past the end of the `user_name` array, the processor will throw a *capability fault*, and execution of our program will cease.
 
-the idea behind CHERI is that we don't have to set up these bounds ourselves. this is something the compiler can generate code for. the compiler knows that the `user_name` array has a length of `32`, and can set the bounds accordingly on capabilities created that point to it. let's try it...
+the idea behind CHERI is that we as the C programmer don't have to set up these bounds ourselves most of the time---this is something the compiler can generate code for. the compiler knows that the `user_name` array has a length of `32`, and can set the bounds accordingly on capabilities created that point to it. let's try it...
 
 
 ## playing with CHERI RISC-V
 unless you're lucky enough to have access to a physical Morello board, there is the issue of actually using a CHERI implementation. for this article I will be making use of the [QEMU](https://en.wikipedia.org/wiki/QEMU) emulator to emulate a [RISC-V](https://en.wikipedia.org/wiki/RISC-V) CHERI environment. running [CheriBSD](https://www.cheribsd.org/) on this emulator will allow us to have a nice [FreeBSD](https://www.freebsd.org/)-based capability-enabled environment to play around with. I'll use [cheribuild](https://github.com/CTSRD-CHERI/cheribuild) to easily get set up (the `cheribuild.py` step will take a very long time the first time):
 
-{% highlight console %}
+```console
 $ sudo apt install autoconf automake libtool pkg-config clang bison cmake \
 ninja-build samba flex texinfo time libglib2.0-dev libpixman-1-dev \
 libarchive-dev libarchive-tools libbz2-dev libattr1-dev libcap-ng-dev
@@ -140,21 +150,23 @@ CheriBSD/riscv (cheribsd-riscv64-purecap) (ttyu0)
 
 login: root
 root@cheribsd-riscv64-purecap:~ #
-{% endhighlight %}
+```
 
-now we have our shell inside our CheriBSD emulated platform, we can start to try things out. let's compile our `membug` program again, this time with the toolchain targetting CheriBSD RISC-V - this will have been built as part of the dependencies already. once it's built, we can `scp` it over to the CheriBSD filesystem, as we set up the SSH forwarding port to 
-`1111`.
+now we have our shell inside our CheriBSD emulated platform, we can start to try things out. let's compile our `membug` program again, this time with the toolchain targetting CheriBSD RISC-V - this will have been built as part of the dependencies already.
 
-{% highlight console %}
-# on a separate terminal on your host machine
+once our `membug-cheribsd` executable is built, we can `scp` it over to the CheriBSD filesystem. remember, we set up the SSH forwarding port to `1111`. 
+
+from a terminal on your host machine:
+
+```console
 $ ~/cheri/output/sdk/utils/cheribsd-riscv64-purecap-clang membug.c -Wall -g -fno-stack-protector -o membug-cheribsd
 $ scp -P 2222 ./membug-cheribsd root@localhost:~/
-{% endhighlight %}
+```
 
 and now we can see what happens when we explore our bug with CHERI:
 
-{% highlight console %}
-$./membug-cheribsd
+```console
+$ ./membug-cheribsd
 enter your name: jack
 hello jack
 my_perfect_string: what a beautiful string
@@ -162,12 +174,12 @@ my_perfect_string: what a beautiful string
 $ ./membug-cheribsd
 enter your name: Hubert Blaine Wolfeschlegelsteinhausenbergerdorff Sr.
 In-address space security exception (core dumped)
-{% endhighlight %}
+```
 
 it's working! we are getting a capability fault as we exceed the bounds of the 
 `user_name` capability bounds. we can use gdb to verify this is caused by the bounds fault:
 
-{% highlight plaintext linenos %}
+```gdb
 (gdb) run
 Starting program: /root/membug-cheribsd 
 enter your name: Hubert Blaine Wolfeschlegelsteinhausenbergerdorff Sr.
@@ -177,11 +189,12 @@ Capability bounds fault caused by register ca6.
 0x0000000040314ce8 in memcpy (dst0=0x3fffdfff44, src0=<optimized out>, length=54) at /home/jack/cheri/cheribsd/lib/libc/string/bcopy.c:143
 (gdb) p $ca6
 $1 = () 0x3fffdfff78 [rwRW,0x3fffdfff44-0x3fffdfff64]
-{% endhighlight %}
+```
 
 as we can see, the bounds for our `user_name` capability (which is stored in capability register `ca6`) are `0x3fffdfff44-0x3fffdfff64`, but the address is `0x3fffdfff78`. this is out of the bounds allowed by the capability, so the architecture throws a fault. if we look at the assembly generated by the compiler, we can see it set our capability bounds to a size of 32 to enforce this behaviour:
 
-{% highlight armasm linenos %}0000000000001ce8 <main>:
+```asm
+0000000000001ce8 <main>:
 ; int main() {
     cincoffset	csp,    csp,        -160
     csc	        cra,    144         (csp)
@@ -198,28 +211,67 @@ as we can see, the bounds for our `user_name` capability (which is stored in cap
     mv	        a1,     zero
     csd	        a1,     -104        (cs0)
     csw	        a1,     0           (ca2)
-{% endhighlight %}
+```
 
-### capability monotonicity
+### chains of capabilities
 at this point you may be thinking "okay, that's great, but if we can just set the bounds of a capability with an instruction then what's the point? surely I can just set global bounds on some random pointer and access whatever I want?"
 
-fundamental to the idea of capabilities is their _provenance_ and _monotonicity_. simply put, the first says we can only construct a capability using specific instructions, from an existing capability. we can't just create a capability from some random number. let's see what happens when we try to run our `ptrs_as_numbers` program on CheriBSD:
+fundamental to the idea of capabilities is their *provenance* and *monotonicity*.
 
-{% highlight plaintext %}
-(gdb) runStarting program: /root/ptrs_as_numbers-cheribsd 
+*provenance*, simply put, means we can only construct a capability from an existing capability, using specific instructions. we can't just create a capability from some random `size_t` and use it to load/store something. let's see what happens when we try to run our `ptrs_as_numbers` program on CheriBSD:
+
+```gdb
+(gdb) run
+Starting program: /root/ptrs_as_numbers-cheribsd 
 *x=1234
-Program received signal SIGPROT, CHERI protection violation.Capability tag fault caused by register ca1.0x0000000000101c66 in main () at ptrs_as_numbers.c:1414          printf("*x=%d\n", *x);
+Program received signal SIGPROT, CHERI protection violation.
+Capability tag fault caused by register ca1.
+0x0000000000101c66 in main () at ptrs_as_numbers.c:1414
+          printf("*x=%d\n", *x);
 (gdb) p $ca1
 $1 = () 0x3fffdfff74
-{% endhighlight %}
+```
 
-we can see we get a fault - the tag isn't set. any capability with a tag not set to 1 cannot be dereferenced - it is invalid. in fact, this capability has no capability metadata - when we copied it into our `unsigned long`, we just copied the 64-bit address.
+we get a fault, because the tag isn't set. any capability with a tag not set to 1 cannot be dereferenced -- it is invalid. in fact, this capability has no capability metadata -- when we copied it into our `unsigned long`, we just copied the 64-bit address.
 
-*monotonicity* is what stops us taking an existing capability, and creating a capability with more permissions and/or access than the original. it stipulates that when we create a capability from another capability (which we have to do - provenance), the permissions and bounds of the new capability must be equal to or less than the original. so our bounds can only get narrower as we create new capabilites from an existing capability. this means that capabilities trace back in a chain - they are all created from other capabilities, and narrowed as necessary. in this case, (simplified) when the kernel loads our program it will give us capabilities that are wide enough to do everything we need to do, and the compiler will try and make sure all the capabilities that we make and use from these are as tightly bound and unpermissive as possible.
+*monotonicity* is what stops us taking an existing capability and creating a capability with more permissions and/or access than the original. it stipulates that when we create a capability from another capability (which we have to do -- provenance), the permissions and bounds of the new capability must be less than or equal to the original. so our bounds can only get narrower as we create new capabilites from an existing capability. this means that capabilities trace back in a chain - they are all created from other capabilities, and narrowed as necessary. in this case, (simplified) when the kernel loads our program it will give us capabilities that are wide enough to do everything we need to do, and the compiler will try and make sure all the capabilities that we make and use from these are as tightly bound and unpermissive as possible.
 
 ### CHERI-fying code
-you'll notice we got a lot of these benefits "for free". we only had to recompile our code, and we got this extra security. of course, CHERI does require changes to programs. naturally, the compiler had to be changed a lot to implement this behaviour. it also especially requires changes to things like the C library and kernel in order to take advantage of the features fully. sufficiently large userspace programs do need changes too. one common issue is that a lot of existing C code assumes that `sizeof (*void) == sizeof(size_t)`. with CHERI, our pointers are now twice as big. however, `size_t` hasn't changed size, as the address space size hasn't changed - for example, if we index into an array with `size_t`, the index should still be the same size; the extra data in our `void *` capability is the metadata, not extra address data. any program that tries to convert from some `unsigned long` or `size_t` to a capability will fault - this violates provenance. so, sometimes code changes have to be made to ensure we are keeping the capability metadata around.
+you'll notice we got a lot of these benefits "for free". we only had to recompile our code, and we gained this extra security. of course, CHERI does require changes to program sources. naturally, the compiler was changed a lot to implement this behaviour. in particular, CHERI also requires changes to things like the C library and kernel in order to take advantage of the features fully. sufficiently large userspace programs will generally require source changes.
 
+one common issue is that a lot of existing C code assumes that `sizeof (*void) == sizeof(size_t)`. with CHERI, our pointers are now twice as big. however, `size_t` hasn't changed size, as the address space size hasn't changed - for example, if we index into an array with `size_t`, the index should still be the same size; the extra data in our `void *` capability is the metadata, not extra address data. any program that tries to convert from some `unsigned long` or `size_t` to a capability will fault - this violates provenance. so, sometimes code changes have to be made to ensure we are keeping the capability metadata around. in CHERI, we can use `ptraddr_t` to store addresses and `[u]intptr_t` to store capabilities.
+
+let's make a program to see some differences in types, and demonstrate how `uintptr_t` can preserve capabilities:
+
+{{ code(path="cheri/ptrtypes.c", syntax="c", linenos=true) }}
+
+running this on our non-CHERI host will give us:
+
+```console
+$ ./ptrtypes                                                        
+type          size (hex)   size (dec)
+=====================================
+uintptr_t     0x08         08
+size_t        0x08         08
+void*         0x08         08
+=====================================
+```
+
+running this on CHERI (64-bit):
+
+```console
+$ ./ptrtypes-cheribsd
+type          size (hex)   size (dec)
+=====================================
+ptraddr_t     0x08         08
+uintptr_t     0x10         16
+size_t        0x08         08
+void*         0x10         16
+=====================================
+*b: 888
+*b: 111
+*b: 999
+```
 
 ## epilogue
 I appreciate this has been a fragmented and surface level introduction to CHERI. hopefully it has provided some education in some basic aims of CHERI regardless. potential benefits and uses for CHERI go much deeper than anything I've touched on here, so please, read more about everything - and get your hands dirty trying out messing about with qemu and CheriBSD!

content/dpdk-summit-2024.md

@@ -0,0 +1,13 @@
++++
+title = "DPDK Summit 2024: OpenSSL Crypto PMD - Analysis and Optimisations"
+date = 2024-10-23
++++
+
+# Summary
+this year I had the opportunity to present my recent work on [DPDK](https://www.dpdk.org/). the work consists of performance analysis and optimisations to the OpenSSL crypto poll mode driver (PMD). I identified several major performance flaws with the implementation, and integration with OpenSSL, and upstreamed changes to address these. the talk goes through the details of the findings, performance impacts of the changes, and discussions around future work.
+
+# Recording
+<iframe width="560" height="315" src="https://www.youtube.com/embed/sPhktvMBYhs?si=UInBMrAUxs2R_raf" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+
+# Slides
+[pdf of the slides used for the talk](/pdf/dpdksummit2024.pdf)

content/sensor-watch.md

@@ -1,7 +1,9 @@
----
-layout: post-sensor-watch
-title: "sensor watch"
----
++++
+title = "sensor watch"
+date = 2022-11-14
+template = "article-sw.html"
++++
+
 
 ## preamble
 some time back I was browsing [Crowd Supply](https://www.crowdsupply.com/) when I came across [the Sensor Watch project](https://www.crowdsupply.com/oddly-specific-objects/sensor-watch) by [Joey Castillo](https://github.com/joeycastillo). I had wanted some kind of "hackable" watch for a while, and had looked at things like [Watchy](https://www.crowdsupply.com/sqfmi/watchy), but this project hit the sweet spot for me. I love my existing F91-W, and this project was a good combination of open source with community software support. one key feature that was important to me is battery life - the Sensor Watch battery life in an average usage scenario is so long that [Joey's is still going strong](https://twitter.com/josecastillo/status/1590066358351298560)!
@@ -22,7 +24,8 @@ this part was out of stock everywhere I initially looked (the usual contenders f
 
 ### PCB and stencil
 for the PCB I opted to go with [JLCPCB](https://jlcpcb.com/). I simply uploaded the relevant gerbers, and adjusted the necessary settings. notably, [the thickness should be 0.6mm](https://github.com/joeycastillo/Sensor-Watch/issues/14#issuecomment-922974276">) - this does narrow the choice of manufacturer (for example, OSH Park doesn't go this thin). I haven't yet ordered any sensor board PCBs, but [PCBWay](https://www.pcbway.com/) seems to be *the* option there. The PCB turned out great, although the silkscreen is a little hard to read at this size due to lack of sharpness: 
-{% picture jpt-webp sensor-watch/pcb.jpg --alt a closeup of a sensor watch PCB %}
+
+{{ image(path="images/sensor-watch/pcb.jpg", alt="a closeup of a green sensor watch PCB") }}
 
 
 ## assembly
@@ -43,7 +46,8 @@ the assembly process is as follows:
 [removing the buzzer connector from your old PCB and soldering it onto the back of the Sensor Watch PCB.](https://youtu.be/Zr0pKeC2VFU?t=185) this will feel blissfully easy after the button! you also have to place the battery clip, but no soldering needed here :).
 
 one area I found particularly difficult was the area with the oscillator crystal and the two 0402 capacitors, C7 and C8. things are a bit cramped here, so extra care was needed:
-{% picture jpt-webp sensor-watch/c7c8.jpg --alt a closeup of a sensor watch PCB, with an area circled. the area contains some small, and closely grouped pads %}
+
+{{ image(path="images/sensor-watch/c7c8.jpg", alt="a closeup of a green sensor watch PCB, with an area circled. the area contains some small, and closely grouped copper pads") }}
 
 
 ## software
@@ -95,8 +99,6 @@ some summary thoughts:
 - if you have a Sensor Watch (or are planning to!) please go ahead and [contribute to movement](https://github.com/joeycastillo/Sensor-Watch) if you have a cool idea. I'm sure some reviews would be helpful to spot any issues on existing PRs before a maintainer gets to them to save some time.
 - the one issue I've had with using my Sensor Watch for TOTP is clock accuracy. the clock drifts over time, so I have to set the time once or twice a week to keep it nice and accurate for the TOTP functionality to be nice to use. but a community member is working on this, and it's going to get a lot better. check out the Discord channel to see some seriously cool engineering going into this calibration effort.
 
-
-{% picture sensor-watch/watch1.jpg --alt a shot of a yellow and black assembled sensor watch, lying horizontally on a surface %}
-{% picture sensor-watch/watch2.jpg --alt a shot of a yellow and black assembled sensor watch, lying vertically on a surface %}
-{% picture sensor-watch/wrist.jpg --alt a shot of a yellow and black assembled sensor watch, on the author's wrist %}
-
+{{ image(path="images/sensor-watch/watch1.jpg", alt="a shot of a yellow and black assembled sensor watch, lying horizontally on a surface") }}
+{{ image(path="images/sensor-watch/watch2.jpg", alt="a shot of a yellow and black assembled sensor watch, lying vertically on a surface") }}
+{{ image(path="images/sensor-watch/wrist.jpg", alt="a shot of a yellow and black assembled sensor watch, on the author's wrist") }}

content/syscalls.md

@@ -0,0 +1,164 @@
++++
+title = "Linux syscall hooking"
+date = 2024-09-26
++++
+
+sometimes, you might want to hook Linux syscalls from a binary. it's probably not for a very elegant reason, but I'm not here to judge. in this article we discuss a few options for doing this. these will be focussed on x86 platforms running Linux, but many of these techniques should also be possible on other ISAs, with appropriate changes.
+
+## binary rewriting
+one way to approach the problem is simply to rewrite binaries at runtime. one can set executable text pages to be writeable, swap out some instructions, and then set them back to be read-only and executable. how can this look in practice?
+
+one has to consider the limitations of binary rewriting in this manner. we can only replace syscall instructions with instructions of the same length. thus, we have limited flexibility in how to implement a syscall hooking function. absolute calls to some custom handler address would require further code modification than is possible, in order to prepare a register with the jump address. we can do relative jumps, but we need to find some space within the maximum range to put our handler function.
+
+### zpoline
+zpoline{{ref(n=1)}} is one approach to get around these limitations, on x86 platforms. zpoline replaces all `syscall`/`sysenter` instructions with `call *%rax`. this takes advantage of two things:
+1. `rax` will always contain the target syscall number, thus holding a bounded low number. this allows us to rewrite the virtual memory in the range `[0x00, (SYSCALL_MAX + n)]` to have some custom handler code of length `n`.
+2. `call *%rax` is the same size as `syscall` (2 bytes){{ref(n=2)}}.
+this means we can `mmap(0)` at the start of runtime, and create fall-through nops, followed by a jump to a syscall hook function. the performance of this should be pretty good, not much different to adding an extra function call to each syscall, which is all we want to do anyway.
+
+okay, but is it ok to `mmap()` the zero virtual address? well, not really. for starters, you probably can't do it as a non-privileged user. Linux has a setting `mmap_min_addr`, which disallows any `mmap()`s below a given address{{ref(n=3)}}. secondly, this can cause certain null-pointer bugs to exhibit weird behaviour, instead of throwing segmentation faults.
+
+thus, this option does work, and may be suitable for certain usecases, but it does have large flaws (like all of the options).
+
+### custom trampolines
+an alternative that doesn't involve `mmap()`ing the zero page is used by AMD's Onload{{ref(n=4)}} - try to replace
+```
+b8 NN NN NN NN          mov    eax,0xN         ; N = syscall number
+0f 05                   syscall
+```
+with
+```
+b8 TT TT TT TT          mov    eax,0xTTTTTTTT  ; 0xTTTTTTTT = trampoline func address
+ff d0                   call   rax
+```
+where `0xTTTTTTTT` is the address of some trampoline function we have crafted. we can get an address to put this function at by using `mmap(..., MMAP_32BIT)`.
+
+another option here is to try to get some virtual memory within a certain distance from the syscall code, and use relative call instructions.
+
+note that this method is not as reliable. it relies on being able to find syscall-performing code which can be modified in this way, which is not guaranteed. thus, it could fail in some situations. it does circumvent the requirement for an ugly `mmap(0)`, however.
+
+## syscall user dispatch (SUD)
+SUD{{ref(n=5)}} is probably the most "correct" way to go about doing this. this kernel feature was initially created for Wine. SUD allows the userspace program to request the kernel traps all syscalls, raising a `SIGSYS` signal every time. a certain range of program memory can be excluded from this trapping, and a flag can be used to toggle trapping off or on at runtime (although the excluded range will never trap, regardless of this flag).
+
+this is is enabled via `prctl()`:
+```c
+int prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, unsigned long off, unsigned long size, int8_t *switch);
+int prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_OFF, 0L, 0L, 0L);
+```
+where `off` is the start of the non-trapping memory region, and `size` is it's length. `switch` is a pointer to the aforementioned toggleable flag.
+
+here is a very basic example of using SUD:
+```c
+#define _GNU_SOURCE
+
+#include <signal.h>
+#include <sys/prctl.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <stdio.h>
+
+bool selector = SYSCALL_DISPATCH_FILTER_ALLOW;
+
+static volatile void handle_sigsys(int sig, siginfo_t *info, void *ucontext) {
+	char buf[128];
+	int len;
+    int ret;
+
+	len = snprintf(buf, 1024, "Caught syscall with number 0x%x\n", info->si_syscall);
+    selector = SYSCALL_DISPATCH_FILTER_ALLOW;
+    write(1, buf, len);
+}
+
+int main(void) {
+    int err;
+
+    /* install SIGSYS signal handler */
+    struct sigaction act;
+    memset(&act, 0, sizeof(act));
+
+	sigset_t mask;
+	sigemptyset(&mask);
+
+	act.sa_sigaction = handle_sigsys;
+	act.sa_flags = SA_SIGINFO;
+	act.sa_mask = mask;
+
+    if (err = sigaction(SIGSYS, &act, NULL)) {
+		printf("sigaction failed: %d\n", err);
+		exit(-1);
+	}
+
+    /* enable SUD */
+    if (err = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 0, 0, &selector)) {
+		printf("prctl failed: %d\n", err);
+		exit(-1);
+	}
+
+    selector = SYSCALL_DISPATCH_FILTER_BLOCK;
+    syscall(SYS_write);
+
+    return 0;
+}
+```
+running this will produce the following:
+```
+Caught syscall with number 0x38
+```
+where syscall number `0x38` is `SYS_write` (on my system).
+
+{% note(header="note") %}
+we've had to disable syscall hooking within `handle_sigsys()`, before we perform the `write` syscall. this could also be achieved using the offset exclusion mechanism, with a caveat: SUD also needs to be disabled at signal handler return. this is because, depending on some factors, the signal handler will return to a signal trampoline, which exists somewhere else in memory (VDSO or libc). this trampoline will then perform the `sigreturn` syscall, which - if you had only excluded the handler function memory itself - would cause us to raise a `SIGSYS` inside a `SIGSYS` handler (oops).
+{% end %}
+
+SUD should have pretty good performance, although it is still switching from user space to kernel space (on syscall), and back again (on SIGSYS handling) - unlike the binary rewriting methods.
+
+## rewriting the kernel syscall table
+Linux kernel modules could also try to patch the kernel's syscall table.
+
+it used to be the case that if Linux is configured with `CONFIG_KALLSYMS_ALL=y`:
+```shell
+$ zgrep CONFIG_KALLSYMS_ALL /proc/config.gz
+CONFIG_KALLSYMS_ALL=y
+```
+then we can find the address of the syscall table in `kallsyms`:
+```shell
+$ sudo grep sys_call_table /proc/kallsyms
+ffffffff854017e0 D sys_call_table
+```
+and thus programmatically:
+```c
+void *sys_call_table = kallsyms_lookup_name("sys_call_table");
+```
+once the syscall table address has been obtained, the handlers for specific syscall(s) could then be overwritten, in order to hook them.
+however, this kind of symbol lookup was generally considered very naughty, and `kallsyms_lookup_name()` was unexported in Linux 5.7{{ref(n=6)}}. there should be some feasible alternatives to do the same thing, but they would be slower, uglier, and more painful.
+
+## modifying IA32_LSTAR MSR
+
+another method which has been used successfully{{ref(n=7)}} involves rewriting the x86 MSR `IA32_LSTAR`. this register holds the destination address which the CPU will load into `RIP` when taking a syscall{{ref(n=2)}}. one can write a kernel module which modifies this register to contain a custom syscall handler address. this syscall handler function can hook syscalls before dispatching as normal (or not).
+
+now that `kallsysms_lookup_name()` is no longer exported, this method also becomes problematic. as the example kernel module in {{ref(n=7,nosup=true)}} demonstrates, we still need to be able to grab some kernel symbol addresses in order to correctly implement the dispatcher.
+
+however, this does propose another idea for implementing the previous method: using `IA32_LSTAR` to ascertain the address of the Linux syscall handler, instead of kallsyms. indeed, Onload has also exploited this method as a workaround for the unexporting of `kallsyms_lookup_name()`{{ref(n=8)}}.
+
+
+## citations
+
+{{ defref(n=1, url="https://www.usenix.org/conference/atc23/presentation/yasukata") }}
+
+{{ defref(n=2, url="https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sdm.html") }} 
+
+{{ defref(n=3, url="https://elixir.bootlin.com/linux/v6.11/source/arch/s390/mm/mmap.c#L137") }} 
+
+{{ defref(n=4, url="https://github.com/Xilinx-CNS/onload/blob/d5984bf52fcfba0cd75df8a1f8828f3363f6e164/src/lib/transport/unix/fdtable.c#L311") }} 
+
+{{ defref(n=5, url="https://docs.kernel.org/admin-guide/syscall-user-dispatch.html") }} 
+
+{{ defref(n=6, url="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0bd476e6c67190b5eb7b6e105c8db8ff61103281") }} 
+
+{{ defref(n=7, url="https://vvdveen.com/data/lstar.txt") }} 
+
+{{ defref(n=8, url="https://github.com/Xilinx-CNS/onload/blob/083e5959ef76632ae3cd3d4356fb079ce0c570d1/src/driver/linux_resource/syscall_x86.c#L347") }} 

content/学中文学了一年了.md

@@ -0,0 +1,18 @@
++++
+title = "学中文学了一年了"
+date = 2024-09-23
++++
+
+大约一年前，我开始认真地学习中文。因此，我觉得我应该写一下我的经历。
+
+我刚开始学习时，我只用了一个方法：[Anki](https://apps.ankiweb.net/)卡片。我也认为在语言学习方法上，Anki是最有效的。但是为了提高听力和口语，它不太好。
+
+这就是为什么去年我也开始在Italki上上课。因为[Italki](https://www.italki.com/)有很多的中文老师，所以你可以选择一个最适合你的学习方式的。对我来说，这是最有效方法提高我的口语。
+
+因为在今年上半年的时候，我还感觉我的听力水平不好，所以我找了方法来提高。我发现了大部分人建议听博客，然后我找到一些有用的博客。我最喜欢的是这些：
+
+1. [听故事说中文](https://open.spotify.com/show/04re9FvL1xviHGWvXKoAhZ?si=d7bc25d6f481427b)
+2. [猫咪中文](https://open.spotify.com/show/7sHdRAysnMygox20EuYlwp?si=6ec8583891484aef)
+3. [茶歇中文](https://open.spotify.com/show/6mJNegfDGmNaG1mWJtZJed?si=15f5851993d74a48)
+
+未来将要发生什么？我还不知道，但是我希望我可以继续进步。明年三月我打算和我的对象一起去中国旅游。其实我十分期待这个旅行，因为我不但没去过中国，甚至连亚洲也没去过！既然中国菜非常好吃，我应该学习怎么流利地点菜。我也希望在中国我可以够有信心尝试和中国人聊聊天儿。

cv/main.tex

@@ -13,6 +13,7 @@
 % Example photograph taken from Wikimedia Commons
 % https://commons.wikimedia.org/wiki/File:Kiara_Krit_passport.jpg
 
+
 \usepackage{simplecv}
 
 \boldname{Bond-Preston}{Jack}{Mr.}
@@ -26,28 +27,19 @@
     Website: \website{jackbondpreston.me} \\ 
     Email: \email{jackbondpreston@outlook.com} \\
     LinkedIn: \linkedin{jack-bond-preston-922706150} \\
-    GitHub: \github{jackbondpreston}
 }
 
-% \headingphoto{Name Surname}{
-%     Website: \website{example.com} \\ 
-%     Email: \email{example@example.edu} \\
-%     LinkedIn: \linkedin{name-surname} \\
-%     GitHub: \github{example}
-% }{photo.jpg}
-
 % Page One
-\import{sections/}{education.tex}
 \import{sections/}{experience.tex}
-%\import{sections/}{publications.tex}
+\import{sections/}{skills.tex}
 
-%\pagebreak
+\pagebreak
 
 % Page Two
 %\import{sections/}{teaching.tex}
-% \sidebyside
-\import{sections/}{skills.tex}
-    % {\import{sections/}{languages.tex}}
+\import{sections/}{education.tex}
+\import{sections/}{publications.tex}
+\import{sections/}{languages.tex}
 %\import{sections/}{projects.tex}
 %\import{sections/}{awards.tex}
 %\import{sections/}{extracurricular.tex}

cv/sections/education.tex

@@ -6,9 +6,4 @@
 \entrybig
     {\textbf{University of Bristol}}{Bristol, UK}
         {BSc in Computer Science (1st Class Hons)}{2017\textendash 2020}
-        \vspace{-0.75em}
-\innerlist{
-    \entry{Awarded prize for best second-year group software development project.}
-}
-
 }

cv/sections/experience.tex

@@ -4,33 +4,47 @@
 \outerlist{
 
 \entrybig
-	{\textbf{AMD, Inc. (formerly Xilinx)}}{Cambridge, UK}
-		{Software Engineer in Adaptive and Embedded Computing Group}{2022\textendash Current}
+	{\textbf{Arm Ltd.}}{Cambridge, UK (Hybrid)}
+		{Software Engineer in Infrastructure Application Solutions group}{2023\textendash Current}
 \innerlist{
-	\entry{Developing AMDs Onload userspace network stack.}
+	\entry{Contributing to the open source DPDK (Data Plane Development Kit) project (using C), including making large performance improvements to the OpenSSL PMD (Poll-Mode Driver) - as well as changes to OpenSSL itself (using C and arm64 assembly).}
+	\entry{Research and implementations in the area of HPC/AI infrastructure/networking, especially RDMA and memory management on heterogeneous memory systems - comprising work on projects including PyTorch (using C++ and Python), Gloo (using C++).}
+	\entryextra{Coordinating collaboration between IAS and Secure Libraries teams, helping to ensure enablement of competitive IPSec performance on Arm platforms.}
+	\entryextra{Technical mentorship for graduate engineer.}
+	\entryextra{Code reviews across multiple projects including DPDK [C], PyTorch [C++, Python], OpenSSL [C, arm64 assembly], VPP [C], Snort3 [C++].}
+	\entryextra{Knowledge sharing documents and presentations, especially around OpenSSL performance work and heterogeneous memory management.}
 }
 
 \entrybig
-	{\textbf{Arm Ltd.}}{Cambridge, UK}
+	{\textbf{AMD (formerly Xilinx / Solarflare)}}{Cambridge, UK (Hybrid)}
+		{Software Engineer in Adaptive and Embedded Computing Group}{2022\textendash 2023}
+\innerlist{
+	\entry{Developing AMDs transparent, ultra-low-latency, kernel-bypass network stack - Onload - using C.}
+	\entryextra{Performance optimisation and benchmarking/profiling work.}
+	\entryextra{Improvements, debugging, and bugfixes for teaming/bonding support.}
+	\entryextra{Extending and modernising internal automated tests}
+}
+
+\entrybig
+	{\textbf{Arm Ltd.}}{Cambridge, UK (Hybrid)}
 		{Graduate Software Engineer in Open Source Software Group}{2021\textendash2022}
 \innerlist{
 	\entry{Porting low-level software to the Morello (CHERI) platform.}
-	\entryextra{Produced patches in C and AArch64 assembly as part of a project porting the open-source C standard library implementation musl to a new prototype platform.}
+	\entryextra{Produced patches as part of a project porting the open-source C standard library implementation musl to a new prototype platform (using C and arm64 assembly).}
 	\entryextra{Ported larger components of the C library, including the memory allocator and POSIX threads. Considered security and hardening against memory safety bugs at every stage of design and implementation.}
 	\entryextra{Created a minimal test distribution of Linux for use on an Arm Fixed Virtual Platform, with the ability to run userspace applications in pure-capability mode. This provided the framework for adding FVP-based testing to the CI pipeline (alongside existing emulator-based testing) for further proof of functionality.}
 	\entryextra{Liased with multiple teams to ensure coordination between libc, kernel ABI, compilers and debuggers.}
-	\entryextra{Provided code review including feedback and improvements for patches developed by others for the musl project.}
 }
-
-\entrybig
-	{\textbf{University of Bristol}}{Bristol, UK}
-	{Teaching Assistant in Department of Computer Science}{2019\textendash 2020}
-    \innerlist{
-    	\entry{Delivered and created content for several Computer Science courses, including content involving operating systems, concurrency, and a software engineering project.}
-    	\entryextra{Provided guidance and troubleshooting assistance to students in both in-person and online lab sessions, including for a course in which students develop a basic Armv7-A multitasking kernel.}
-    	\entryextra{Interviewed students in viva-style coursework assessments, and assisted with subsequent coursework marking.}
-    	\entryextra{Assisted with the creation and improvement of lab sheets (including skeleton and solution code).}
-    }
+%
+%\entrybig
+%	{\textbf{University of Bristol}}{Bristol, UK}
+%	{Teaching Assistant in Department of Computer Science}{2019\textendash 2020}
+%    \innerlist{
+%    	\entry{Delivered and created content for several Computer Science courses, including content involving operating systems, concurrency, and a software engineering project.}
+%    	\entryextra{Provided guidance and troubleshooting assistance to students in both in-person and online lab sessions, including for a course in which students develop a basic Armv7-A multitasking kernel.}
+%    	\entryextra{Interviewed students in viva-style coursework assessments, and assisted with subsequent coursework marking.}
+%    	\entryextra{Assisted with the creation and improvement of lab sheets (including skeleton and solution code).}
+%    }
     
     
 % \entrybig

cv/sections/languages.tex

@@ -2,6 +2,7 @@
 \section{Languages}
 
 \denseouterlist{
-\entry{\textbf{English:} Native speaker}
-\entry{\textbf{German:} CEFR A2/B1 (Elementary/Low Intermediate)}
+\entry{\textbf{English:} Native}
+\entry{\textbf{Mandarin Chinese:} HSK 3 (2024)}
+\entry{\textbf{German:} CEFR A2 (2020)}
 }

cv/sections/publications.tex

@@ -1,9 +1,13 @@
 
-\nocite{*}
-\printbibliography[title=Publications]
+\section{Presentations}
 
-% Can instead manually enter publications as shown:
-% \section{Publications}
-% \orderedouterlist{
-% \entry{S. Petridis, J. Shen, \textbf{D. Cetin} and M. Pantic, "Visual-Only Recognition of Normal, Whispered And Silent Speech", \textit{IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), April 2018}}
-% }
+\outerlist{
+	
+	\entrybig
+	{\textbf{DPDK Summit}}{Online Presentation}
+	{\href{https://www.youtube.com/watch?v=sPhktvMBYhs}{OpenSSL Crypto PMD - Analysis and Optimisations}}{October 2024}
+	\innerlist{
+		\entry{Submitted and delivered a talk on my work optimising DPDK's OpenSSL Poll Mode Driver (PMD), along with potential future work and points requiring community coordination.}
+		\entryextra{Fielded and answered numerous questions from community members.}
+	}
+}

cv/sections/skills.tex

@@ -2,10 +2,10 @@
 \section{Skills}
 
 \denseouterlist{
-\entry{\textbf{Low-Level Software \& Architecture:} C, C++ (inc. 11/17/20 standards), Armv7/8/9 (assembly \& architecture), RISC-V, CHERI, GNU Make, CMake.}
-\entry{\textbf{Software Engineering:} Git, Gerrit, Linux, Bash \& Zsh, Python, Java, Haskell, Agile, Jira.}
-\entry{\textbf{Web Development:} HTML5, Modern CSS, ECMAScript 2015+ \& Typescript, Vue.js, Spring Boot, SQL.}
-\entry{\textbf{Teaching:} Giving lectures \& seminars, interviewing, marking coursework, giving knowledge sharing presentations.}
-\entry{\textbf{Design:} 3D modelling, vector graphics, Photoshop.}
+\entry{\textbf{Programming Languages:} C, C++, Python, Assembly (x86-64 and AArch64)}
+\entry{\textbf{Debugging and Performance:} Perf, GDB \& LLDB, rr, Flamegraph, Wireshark}
+\entry{\textbf{Architecture:} Arm Architecture, Arm Standard Interconnects, PCIe, Heterogeneous Systems}
+\entry{\textbf{Build Systems:} GNU Make, CMake, Meson}
+\entry{\textbf{Software Engineering:} Python, Git, Gerrit, Linux, Shell Scripting, Agile, Jira}
 
 }

cv/simplecv.sty

@@ -10,10 +10,19 @@
 \usepackage{enumitem}                       % List customization
 \usepackage{lastpage}                       % Page numbering
 \usepackage{fancyhdr}                       % Footers
-\usepackage[russian,english]{babel}         % Language styles
+\usepackage[english]{babel}         % Language styles
 \usepackage{graphicx}                       % Importing graphics
 \usepackage[export]{adjustbox}              % Aligning margins
 
+\hypersetup{
+	colorlinks=true,
+	linkcolor=blue,
+	filecolor=magenta,      
+	urlcolor=blue,
+	pdftitle={Overleaf Example},
+	pdfpagemode=FullScreen,
+}
+
 % % Chinese
 % \usepackage{xeCJK}
 % \setCJKmainfont{BabelStone Han}

index.md

@@ -1,32 +0,0 @@
----
-layout: default
-title: jack bond-preston
----
-
-# jack bond-preston
-
-## contact
-you can contact me via [email](mailto:jackbondpreston@outlook.com) or on [linkedin](https://www.linkedin.com/in/jack-bond-preston-922706150/)
-
-my cv is available for viewing [here](cv.pdf).
-
-## open source
-
-i have personal accounts on [github](https://github.com/jackbondpreston) and [gitlab](https://gitlab.com/jackbondpreston)
-
-
-some of my work at arm on [morello](https://www.arm.com/architecture/cpu/morello) is available on the 
-d [morello musl gitlab](https://git.morello-project.org/morello/musl-libc/-/commits/morello/master?author=Jack%20Bond-Preston) 
-
-
-my [onload](https://www.xilinx.com/products/boards-and-kits/x2-series/onload.html) commits at amd can be found on [the github repo](https://github.com/Xilinx-CNS/onload/commits?author=jbondpre-amd) 
-
-
-## articles
-
-{% for post in site.posts %}
-<li>
-    [{{ post.date | date: "%d/%m/%Y" }}] <a href="{{ post.url }}">{{ post.title }}</a>
-</li>
-{% endfor %}
-

sass/style/_colours.scss

@@ -0,0 +1,5 @@
+$background-color: rgb(12, 17, 20);
+$body-color: rgb(252, 252, 252);
+$heading-color: rgb(255, 182, 193);
+$link-color: rgb(252, 169, 184);
+$inl-code-color: rgb(165, 214, 255);

sass/style/article.scss

@@ -0,0 +1,103 @@
+@import "_colours";
+
+.article {
+  p,
+  li {
+    a {
+      font-weight: normal;
+      text-decoration: underline;
+      word-wrap: break-word;
+    }
+
+    code {
+      color: #a5d6ff;
+    }
+  }
+
+  picture img,
+  p img {
+    max-width: 100%;
+    display: block;
+  }
+
+  code,
+  pre {
+    font-family: "Source Code Pro";
+  }
+
+  pre {
+    padding: 10px;
+    overflow: auto;
+
+    mark {
+      display: block;
+      background-color: rgba(254, 252, 232, 0.9);
+    }
+
+    table {
+      width: 100%;
+      border-collapse: collapse;
+
+      td {
+        padding: 0;
+      }
+
+      td:nth-of-type(2) {
+        padding-left: 15px;
+      }
+
+      td:nth-of-type(1) {
+        text-align: right;
+        user-select: none;
+        padding-right: 10px;
+        border-right: 3px solid #c0c5ce;
+      }
+    }
+  }
+
+  .header-link {
+    display: inline-block;
+  }
+
+  h1 {
+    display: flex;
+    justify-content: space-between;
+
+    @media screen and (max-width: 450px) {
+      display: block;
+
+      .home-link {
+        display: block;
+      }
+    }
+
+    .home-link {
+      font-size: 0.5em;
+      color: $body-color;
+    }
+  }
+
+  .note {
+    line-height: inherit;
+    margin: 1.25em 0;
+    padding: 6px 12px;
+    display: flex;
+    gap: 12px;
+    border-left: 1px solid $heading-color;
+
+    .icon svg {
+      height: 1.3em;
+      display: flex;
+      align-items: center;
+      color: $heading-color;
+    }
+
+    p {
+      margin-top: 0;
+    }
+
+    p:last-child {
+      margin-bottom: 0;
+    }
+  }
+}

sass/style/main.scss

@@ -0,0 +1,111 @@
+@import "_colours";
+
+@font-face {
+  font-family: 'Source Code Pro';
+  font-style: normal;
+  font-weight: 400;
+  src: local(''),
+       url('/fonts/source-code-pro-v22-latin-ext_latin-regular.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
+       url('/fonts/source-code-pro-v22-latin-ext_latin-regular.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
+}
+
+@font-face {
+  font-family: 'Source Code Pro';
+  font-style: normal;
+  font-weight: 700;
+  src: local(''),
+       url('/fonts/source-code-pro-v22-latin-ext_latin-700.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
+       url('/fonts/source-code-pro-v22-latin-ext_latin-700.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
+}
+
+@font-face {
+  font-family: 'Source Code Pro';
+  font-style: italic;
+  font-weight: 400;
+  src: local(''),
+       url('/fonts/source-code-pro-v22-latin-ext_latin-italic.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
+       url('/fonts/source-code-pro-v22-latin-ext_latin-italic.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
+}
+
+@font-face {
+  font-family: 'Source Code Pro';
+  font-style: italic;
+  font-weight: 700;
+  src: local(''),
+       url('/fonts/source-code-pro-v22-latin-ext_latin-700italic.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
+       url('/fonts/source-code-pro-v22-latin-ext_latin-700italic.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
+}
+
+@font-face {
+  font-family: 'Noto Sans CJK';
+  font-style: normal;
+  font-weight: 400;
+  src: local(''),
+       url('/fonts/NotoSansCJKsc-Regular.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
+       url('/fonts/NotoSansCJKsc-Regular.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
+}
+
+@font-face {
+  font-family: 'Noto Sans CJK';
+  font-style: normal;
+  font-weight: 700;
+  src: local(''),
+       url('/fonts/NotoSansCJKsc-Bold.woff2') format('woff2'), /* Chrome 26+, Opera 23+, Firefox 39+ */
+       url('/fonts/NotoSansCJKsc-Bold.woff') format('woff'); /* Chrome 6+, Firefox 3.6+, IE 9+, Safari 5.1+ */
+}
+
+body {
+  background-color: $background-color;
+  color: $body-color;
+  padding-left: 5vw;
+  padding-right: 5vw;
+  padding-top: 5vh;
+  font-family: 'Source Code Pro', 'Noto Sans CJK';
+  font-size: 1.5rem;
+
+  @media screen and (max-width: 600px) {
+    font-size: 1rem;
+  }
+}
+
+h1 {
+  color: $heading-color;
+  margin: 0;
+}
+
+h2 {
+  margin: 0;
+  margin-top: 3rem;
+  margin-bottom: 0.5rem;
+}
+
+a {
+  color: $link-color;
+  font-weight: bold;
+  text-decoration: none;
+}
+
+li {
+  line-height: 150%;
+}
+
+h2 {
+  a.header-link {
+    display: none;
+
+    img {
+      height: 1.25rem;
+      margin-bottom: -4px;
+    }
+  }
+
+  a.header-link, a.atom-link {
+    padding-left: 10px;
+    font-weight: normal;
+    font-size: 1.3rem;
+  }
+}
+
+img {
+  max-width: 100%;
+}

sass/style/sensor-watch.scss

@@ -0,0 +1,60 @@
+body {
+    padding: 0;
+    margin: 0;
+    min-height: 100vh;
+}
+
+.wrapper {
+    display: grid;
+    grid-template-columns: 30rem auto;
+    grid-template-rows: auto;
+    gap: 0;
+    min-height: 100vh;
+}
+
+.article {
+    padding: 5rem;
+    padding-bottom: 1rem;
+}
+
+.side {
+    background-image: url(/images/sensor-watch/f91w-strap.svg);
+    background-repeat: repeat-y;
+}
+
+.side>svg {
+    width: 30rem;
+    position: fixed;
+}
+
+@media only screen and (max-width: 1500px) {
+    .wrapper {
+        grid-template-columns: 10rem auto;
+        grid-template-rows: auto;
+    }
+
+    .side>svg {
+        width: 10rem;
+    }
+
+    .article {
+        padding-left: 3rem;
+        padding-right: 1rem;
+        padding-top: 1rem;
+    }
+}
+
+@media only screen and (max-width: 800px) {
+    .side {
+        display: none;
+    }
+
+    .wrapper {
+        grid-template-columns: auto;
+        grid-template-rows: auto;
+    }
+
+    .article {
+        padding: 1rem;
+    }
+}

static/images/info.svg

@@ -0,0 +1,2 @@
+
+<?xml version="1.0" ?><svg height="48" viewBox="0 0 48 48" width="48" xmlns="http://www.w3.org/2000/svg"><path d="M22 34h4v-12h-4v12zm2-30c-11.05 0-20 8.95-20 20s8.95 20 20 20 20-8.95 20-20-8.95-20-20-20zm0 36c-8.82 0-16-7.18-16-16s7.18-16 16-16 16 7.18 16 16-7.18 16-16 16zm-2-22h4v-4h-4v4z" fill="currentColor"/></svg>

templates/anchor-link.html

@@ -0,0 +1 @@
+{% if level == 2 %}<a href="#{{ id }}" aria-label="Anchor link for: {{ id }}" class="header-link">[<img src="/images/link.svg" />]</a>{% endif %}

templates/article-sw.html

@@ -0,0 +1,141 @@
+{% extends "base.html" %}
+
+{% block title %}
+{{ page.title }}
+{% endblock %}
+
+{% block extra_head %}
+<link rel="stylesheet" href="/style/article.css">
+<link rel="stylesheet" href="/style/sensor-watch.css">
+{% endblock %}
+
+{% block content %}
+<div class="wrapper">
+    <div class="side">
+        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 300 500">
+            <defs>
+                <style>
+                    .cls-1 {
+                        fill: #0c1113;
+                    }
+
+                    .cls-2 {
+                        fill: none;
+                        stroke: #f6b4c1;
+                        stroke-miterlimit: 10;
+                        stroke-width: 2px;
+                    }
+
+                    .cls-3 {
+                        fill: #f6b4c1;
+                    }
+                </style>
+            </defs>
+            <g id="Layer_5" data-name="Layer 5">
+                <rect class="cls-1" width="300" height="500" />
+            </g>
+            <g id="Layer_1" data-name="Layer 1">
+                <path class="cls-2"
+                    d="M150,335.07c-21-.18-53.88.56-76.78-1-1.15.37-6.4-1.85-7.11-3.33-11.43-13.68-14.6-19.62-14.67-31.33-1-13-1.27-26.4-2-49.34" />
+                <path class="cls-2"
+                    d="M150,329.83c-20.3-.19-49.15.57-71.32-1-1.12.37-7.19-1.87-7.89-3.38-11.06-13.86-13.12-19.87-13.19-31.74-.92-13.2-1-20.39-1.73-43.63" />
+                <path class="cls-2"
+                    d="M150,352.07S59.42,351,58.31,350.52s-20.67-32.89-21.11-34-2.89-66.45-2.89-66.45" />
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+                    d="M150,364.3s-93.23-1-94.34-1.42S28.31,318.3,27.86,317.19s-2.65-67.12-2.65-67.12" />
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+                    d="M150,306.44H125.88c-1.36,0-2,.2-2.44.84-.28.44-.28.44-.56,1.94a24.24,24.24,0,0,0,0,6.59,9.45,9.45,0,0,0,2.39,4.66c1.22,1,3.81,3.56,5.47,3.61s19.25,0,19.25,0" />
+                <polygon class="cls-3"
+                    points="63.43 307.26 118.99 307.26 118.99 309.26 63.91 309.26 63.43 307.26" />
+                <polyline class="cls-2" points="149.99 110.44 63.43 110.44 55.66 137.19" />
+                <polygon class="cls-3"
+                    points="62.63 195.75 149.99 195.75 149.99 193.75 63.11 193.75 62.63 195.75" />
+                <line class="cls-2" x1="65.99" y1="110.44" x2="65.99" />
+                <line class="cls-2" x1="65.99" y1="389.42" x2="65.99" y2="500" />
+                <polyline class="cls-2" points="149.99 389.42 63.43 389.42 55.66 362.67" />
+                <path class="cls-2"
+                    d="M150,306.44h24.11c1.36,0,2,.2,2.45.84.27.44.27.44.55,1.94a24.24,24.24,0,0,1,0,6.59,9.45,9.45,0,0,1-2.39,4.66c-1.22,1-3.8,3.56-5.47,3.61s-19.25,0-19.25,0" />
+                <polygon class="cls-3" points="236.56 307.26 181 307.26 181 309.26 236.08 309.26 236.56 307.26" />
+                <polyline class="cls-2" points="150 110.44 236.56 110.44 244.33 137.19" />
+                <polygon class="cls-3" points="237.36 195.75 150 195.75 150 193.75 236.89 193.75 237.36 195.75" />
+                <line class="cls-2" x1="234" y1="110.44" x2="234" />
+                <line class="cls-2" x1="234" y1="389.42" x2="234" y2="500" />
+                <polyline class="cls-2" points="150 389.42 236.56 389.42 244.33 362.67" />
+            </g>
+        </svg>
+    </div>
+    <div class="article">
+        <h1><a href="{{ page.permalink }}">{{ page.title }}</a></a><span class="home-link">[ <a href="/">homepage</a> ]</span></h1>
+
+        {{ page.content | safe }}
+
+        <hr>
+
+        <p><a href="mailto:jack@jackbondpreston.me">email me</a> to have a conversation</p>
+    </div>
+</div>
+{% endblock %}

templates/article.html

@@ -0,0 +1,21 @@
+{% extends "base.html" %}
+
+{% block title %}
+{{ page.title }}
+{% endblock %}
+
+{% block extra_head %}
+<link rel="stylesheet" href="/style/article.css">
+{% endblock %}
+
+{% block content %}
+<div class="article">
+    <h1><a href="{{ page.permalink }}">{{ page.title }}</a><span class="home-link">[ <a href="/">homepage</a> ]</span></h1>
+
+    {{ page.content | safe }}
+
+    <hr>
+
+    <p><a href="mailto:jack@jackbondpreston.me">email me</a> to have a conversation</p>
+</div>
+{% endblock content %}

templates/base.html

@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+
+<!--
+
+	　 ／l、
+	ﾞ（ﾟ､ ｡ ７
+	　l、ﾞ ~ヽ
+	　じしf_, )ノ
+
+-->
+
+<html lang="en-GB">
+
+<head>
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <meta charset="utf-8">
+  <title>{% block title %} {% endblock %}</title>
+  <link rel="stylesheet" href="/style/main.css">
+  {% block extra_head %} {% endblock %}
+</head>
+
+<body>
+  {% block content %} {% endblock %}
+</body>
+
+</html>

templates/index.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+
+{% block title %}{{ section.title }}{% endblock title %}
+
+{% block content %}
+{{ section.content | safe }}
+
+<ul>
+{% for page in section.pages %}
+<li><a href="{{ page.permalink | safe }}">[{{ page.date }}] {{ page.title }}</a></li>
+{% endfor %}
+</ul>
+{% endblock content %}

templates/shortcodes/code.md

@@ -0,0 +1,4 @@
+{% set code = load_data(path="code/" ~ path) -%}
+```{% if syntax %}{{ syntax }}{% endif %}{% if linenos %}, linenos{% endif %}
+{{ code }}
+```

templates/shortcodes/defref.html

@@ -0,0 +1 @@
+<p id="ref{{ n }}">[{{ n }}] <a href="{{ url }}">{{ url }}</a> <a href="javascript:history.back()" style="text-decoration: none;">(↑)</a></p>

templates/shortcodes/image.html

@@ -0,0 +1,5 @@
+{% set image = resize_image(path=path, width=1024, height=1024, op="fit", format="webp") %}
+{% set url = get_url(path=path) %}
+<a href="{{ url }}">
+<img src="{{ image.url }}"{% if alt %} alt="{{ alt }}"{% endif %} />
+</a>

templates/shortcodes/note.html

@@ -0,0 +1,12 @@
+<blockquote class="note">
+    {% set icon = load_data(path="static/images/info.svg") %}
+    <div class="icon">
+        {{ icon | safe }}
+    </div>
+    <div class="content">
+        {% if header %}
+        <p><strong>{{ header }}</strong></p>
+        {% endif %}
+        {{ body | markdown | safe }}
+    </div>
+</blockquote>

templates/shortcodes/ref.html

@@ -0,0 +1 @@
+{% if not nosup %}<sup>{% endif %}<a href="#ref{{ n }}" style="text-decoration: none;">[{{ n }}]</a>{% if not nosup %}</sup>{% endif %}