iankronquist

Design of the Kernel of Truth Memory System

• Uses PAE paging.
• Higher half memory model.

Initialized in this order:

0. Bootstrap PAE paging.
1. Kernel heap.
2. Physical allocator.
3. Init process PAE paging.

iankronquist

00000000000000c0 <vmxoff>:
  c0:   e8 00 00 00 00          callq  c5 <vmxoff+0x5>
  c5:   55                      push   %rbp
  c6:   48 89 e5                mov    %rsp,%rbp
  c9:   48 83 ec 10             sub    $0x10,%rsp
  cd:   65 48 8b 04 25 28 00    mov    %gs:0x28,%rax
  d4:   00 00 
  d6:   48 89 45 f8             mov    %rax,-0x8(%rbp)
  da:   31 c0                   xor    %eax,%eax
  dc:   0f 01 c4                vmxoff 

iankronquist

We're going to focus on x86 because it's the easiest to understand. I'll then explain how x86_64 is more efficient.

So the stack is where local variables are stored. It is just a chunk of memory available for the program. The top of the stack is stored in a special register called the stack pointer, or esp on x86. It grows from higher addresses to lower addresses. To put a value on the stack you can

iankronquist

You made a device driver! Let's say you named it sbd.

Let's start by recalling that on Linux, everything is a file. There is a file on the filesystem representing every device. On many linux laptops you can see things like /dev/mouse, /dev/speakers, and /dev/cpu. Your driver acts like a hard drive as far as Linux is concerned.

Now, if you start up the vm, you'll see that the device isn't loaded by default:

$ ls /dev/sbd
No such file or directory

iankronquist

Description='eduroam'
Interface=YOUR_INTERFACE
Connection=wireless
ESSID=eduroam
Security=wpa-configsection
IP=dhcp
TimeoutWPA=10
WPAConfigSection=(
    'ssid="eduroam"'
    'proto=RSN WPA'

iankronquist

#include <stdio.h>
#include <unistd.h>
int main () {
    unsigned long long i;
	while (1) {
		printf("tick\n");
        for (i = 1; i != 0; i++){}
	}
}

iankronquist

Ian Kronquist

[iankronquist@teleport.com][1]
844 West Complex • Corvallis, Oregon 97331–1801
Github: [iankronquist][2] • IRC: muricula on Freenode

Enthusiastic and experienced student of computer science, enjoys solving the difficult problems which make the field fascinating. A quick learner eager to apply new concepts and technologies.

Education

iankronquist

Here is a quick intro for how to use strings for those not very familiar with puppet and the command line.

Setup

Do this once to get strings set up:

1. Installing strings

$ puppet module install puppetlabs-strings

iankronquist

def fib (a, b, max ):
	while (b < max):
		tmp = a
		a = b
		b = a + b
	return b

iankronquist

{
    "defined_types": [
        {
            "docstring": "Docstring",
            "file": "manifests/defined_type.pp",
            "line": 6,
            "name": "bar",
            "parameters": {
                "barname": null,
                "barval": null