---
name: "glxsb"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/glxsb"
---

# glxsb(4)

Geode LX Security Block crypto accelerator

## NAME

**glxsb** – Geode LX Security Block crypto accelerator

## SYNOPSIS

To compile this driver into the kernel, place the following lines in your kernel configuration file:

**device crypto** **device glxsb**

Alternatively, to load the driver as a module at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
glxsb_load="YES"
```

## DESCRIPTION

The **glxsb** driver supports the security block of the Geode LX series processors. The Geode LX is a member of the AMD Geode family of integrated x86 system chips.

Driven by periodic checks for available data from the generator, **glxsb** supplies entropy to the [random(4)](/random/4.md) driver for common usage.

**glxsb** also supports acceleration of AES-128-CBC operations for [crypto(4)](/crypto/4.md). It also registers itself to accelerate other HMAC algorithms, although there is no hardware acceleration for those algorithms. This is only needed so **glxsb** can work with [ipsec(4)](/ipsec/4.md).

## CAVEAT

The [crypto(9)](/crypto/9.md) framework will fail to open the crypto session on the device if the AES key's length is != 128 bits. This prevents the use of the **glxsb** device driver with AES keys of length != 128 bits.

## SEE ALSO

[crypto(4)](/crypto/4.md), [intro(4)](/intro/4.md), [ipsec(4)](/ipsec/4.md), [pci(4)](/pci/4.md), [random(4)](/random/4.md), [crypto(7)](/crypto/7.md), [crypto(9)](/crypto/9.md)

## HISTORY

The **glxsb** device driver first appeared in OpenBSD 4.1. The **glxsb** device driver was imported into FreeBSD 7.1.

## AUTHORS

The **glxsb** device driver was written for OpenBSD by Tom Cosgrove. It was ported to FreeBSD by Patrick Lamaiziere ⟨*patfbsd@davenulle.org*⟩.