367 lines
17 KiB
Markdown
367 lines
17 KiB
Markdown
---
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title: Software and hardware freedom status for each mainboard supported by Libreboot
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x-toc-enable: true
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...
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Introduction
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============
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This page documents how Libreboot's [binary blob reduction
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policy](news/policy.md), adopted in November 2022, is implemented in practise,
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especially that line which says: *"if free software can be used, it must be
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used."*
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Libreboot uses [coreboot](https://coreboot.org/) for hardware initialisation.
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While coreboot is nominally [*free* or *open source*
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software](https://writefreesoftware.org/), on *some* (not
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all) platforms, coreboot *requires* certain
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[vendor files](https://en.wikipedia.org/wiki/Binary_blob)
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for things like raminit. *All* boards currently supported by Libreboot can be
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initialised entirely with *free*, *libre* or *open source* code from *coreboot*
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itself, because Libreboot currently only focuses on such mainboards. Libreboot's
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goal is to eventually support *all* mainboards from coreboot.
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A more *pragmatic* [binary blob reduction policy](news/policy.md) was adopted
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by Libreboot during November 2022, as part of an ongoing campaign to support
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more hardware (from coreboot) within Libreboot, so as to provide *many more*
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people with coreboot which, regardless of freedom status, *does* provide increased
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[software freedom](https://writefreesoftware.org/) compared to fully proprietary
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boot firmware which is what most
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people would otherwise use; Libreboot's modern policy is thus pragmatic, further
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advancing the cause of *software freedom*.
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Libreboot's *previous* policy was to *ban all binary blobs*. This actively
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*harmed* the Free Software movement, by reducing the number of people who can
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realistically use coreboot because, to this day, nothing quite like Libreboot
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yet exists. Libreboot's main purpose is to make coreboot *as easy to use as
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possible* for normal, non-technical users who like the idea of coreboot but
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who are otherwise not competent to configure it from scratch. Such harm
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was *corrected*, in November 2022.
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Coreboot architecture
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---------------------
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For context about certain topics, please read:
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<https://doc.coreboot.org/getting_started/architecture.html>
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100% libre init in coreboot
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===========================
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The reason this distinction matters (referring specifically to coreboot's side
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of the initialisation) will become clearer, in the following sections:
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A universal exemption is made in Libreboot, permitting (read: requiring, per
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project policy) the inclusion of CPU microcode updates if available. You can
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read more about that and the reasons *why* by reading the following article:
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[CPU microcode updates
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are **OK**](news/policy.md#more-detailed-insight-about-microcode)
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[Releases after Libreboot 20230423 will provide separate ROMs with microcode
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excluded, alongside default ones with microcode included.](news/microcode.md)
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Intel platforms
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===============
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Descriptor vs descriptorless setup
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----------------------------------
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Libreboot supports several mainboards using Intel platforms. Of these, there
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are essentially two class of machine (for the purposes of this article):
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* Descriptorless configuration
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* Descriptor-based configuration
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What does *descriptor* mean? Well, traditionally, the main flash IC (containing
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the boot firmware, commonly referred to as *the BIOS*) on Intel machines,
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contained only *x86* executable code, responsible for initialising all of
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the hardware, such as the CPU, memory controller and peripherals. This is
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what we will refer to as the *descriptorless* setup; in such configurations,
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the Intel ME firmware is absent by default.
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In a *descriptor* configuration, the flash is divided into regions such as:
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* Intel flash descriptor: always the first 4KiB of the flash. Binary-encoded
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configuration data for the machine, and the regions (such as this, or
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others below) is defined in here. In some ways, you might think of this as
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analagous to the *Master Boot Record* on a hard drive.
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* Intel GbE NVM (gigabit ethernet non-volatile memory): binary-encoded
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configuration data, for the onboard Intel gigabit ethernet device, if one is
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present. It contains lots of settings like MAC address, what speed the NIC
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should run at, PCI IDs, *LED blinking speed* and more.
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If a non-Intel NIC is used, this region of the flash will not be present.
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* ME (Intel Management Engine): a *nasty* security liability in its default
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state, the ME provides many features such as remote management, with full
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networking, The ME is a dedicated coprocessor separate from the main CPU, and
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the initialisation firmware plus operating system for it is loaded from
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this dedicated region in the main boot flash. More info is available [in the
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FAQ](faq.md#intelme) - where ME firmware is otherwise present, Libreboot
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either [removes](docs/install/ich9utils.html) it or (with the `me_cleaner` program) [reconfigures](https://github.com/corna/me_cleaner/wiki/How-does-it-work%3F) it in such
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a way where it is disabled during machine initialisation.
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* Platform region: non-program data, usually just a bunch of strings put there
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by the hardware vendor.
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* BIOS region: this contains the main boot firmware, responsible for
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initialising the CPU, memory controller and peripherals, putting the
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machine into a state where it can run programs (most likely a bootloader,
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then an operating system). The coreboot code (provided by Libreboot) goes in
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here.
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*Basically*, you can think of such "regions" as analogous to *partitions* on
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a hard drive. What's important is that the flash IC is *divided* into such
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regions, where each region is intended for a specific purpose.
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The contents of the *descriptor* and *GbE* regions are described by Intel
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datasheets, but those datasheets often contain *reserved* sections where
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parts are left undocumented. Reverse engineering efforts over the years have
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documented some of these blank spots.
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Libreboot does *not* distribute Intel ME images
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-----------------------------------------------
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Libreboot does *not* distribute the Intel ME firmware in any way, whether in
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the Git repository or in releases. Where it is needed, Libreboot provides
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scripts that automatically fetch and install it, in a *neutered* (disabled)
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state by running the `me_cleaner` program. This is completely automated.
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Please read:
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<https://github.com/corna/me_cleaner/wiki/How-does-it-work%3F>
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The *BringUp* code of Intel ME is all that remains, in Libreboot configurations.
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ME BringUp (BUP) is analogous to coreboot, providing initialisation for the
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ME itself; by that same analogy, the way Libreboot configures it is similar to
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running *coreboot* without a payload. The ME is initialised, to a state where
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it can run code, but then it *doesn't actually run code*. It is thus *disabled*.
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In other words, a *neutered* Intel ME setup is completely benign, both from a
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software freedom and security perspective. It becomes a useless, unused
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processor, that most people in the real world will never want to use anyway.
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With this perspective, we see that Intel ME is now entirely inconsequential
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to the average user.
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*Released* Libreboot ROM images, provided pre-compiled, do *not* include the
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ME firmware at all; they are scrubbed, by automated release scripts when they're
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preparing a release. If you're building from source, the Libreboot build system
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will automatically download it (from the vendor), neuter it and then insert it;
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on release ROMs, the same scripts used by the build systems can (must) be run
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manually, accomplishing the same result after the fact. Please read:
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[docs/install/ivy_has_common.md](docs/install/ivy_has_common.md)
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The ME firmware is *required* on almost all Intel platforms, or the machine
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will turn *off* after 30 minutes (or it will not boot, if the ME also controls
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whether the CPU comes out of reset).
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More about Intel ME removal/disabling
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----------------------------------
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*Libreboot* provides a way to fully remove the ME firmware, while retaining
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full use of the machine, on GM45 platforms with ICH9M southbridge. These are
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laptops: ThinkPad X200/T400/T500/W500 and so on of that generation. See:
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[docs/install/ich9utils.md](docs/install/ich9utils.md)
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The `ich9utils` software is provided by Libreboot. The `ich9gen` utility was
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specifically written by Leah Rowe, in 2014 and improved incrementally since.
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On newer platforms as alluded to above, `me_cleaner` is used instead.
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Notes about specific types of vendor file
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===================================
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VGA option ROMs
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---------------
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*Native* video initialisation is supported and *enabled*, for all supported
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Intel platforms that have it. The source code is provided by coreboot, under
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free license.
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In some cases, a laptop may have a graphics chip that is unsupported by
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coreboot. In this situation, a vendor file called a *VGA Option ROM* must be
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used. Libreboot has *experimental* support for Nvidia GPU models of the Dell
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Latitude E6400, in an experimental branch where the build system automatically
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downloads the VGA ROM for it. This is currently *not* present in releases, or
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in the stable branch of `lbmk`.
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In other instances, a machine may have *two* graphics devices, where one has
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native (free/libre) initialisation provided by coreboot. In these situations,
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it is possible to insert a VGA ROM for the other one; Libreboot currently lacks
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documentation for this, but it has been tested. Example: Dual Intel/Nvidia
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graphics on some ivybridge or haswell thinkpads.
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For *add-on* GPUs, SeaBIOS (payload) can typically scan a VGA ROM present on
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the card and execute it. This has been tested on certain desktop mainboards
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that Libreboot supports, and works just fine; Libreboot does not need to handle
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these files at all.
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Libreboot's default is *always* freedom, when feasible in practise. Users who
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wish to have use of these additional GPUs, on such hardware, must take stock
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of the following paragraph in Libreboot policy:
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*"The principles above should apply to default configurations. However,
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libreboot is to be configurable, allowing the user to do whatever they like."* -
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configurable, it most certainly is! See: [docs/maintain/](docs/maintain/)
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Memory controller initialisation
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--------------------------------
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Libreboot has *fully libre* initialisation available for all Intel memory
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controllers on supported platforms. This *includes* Haswell (ThinkPad T440p
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and W541) as of Libreboot 20230319 or higher.
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ARM platforms (chromebooks)
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=============
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Mostly free software, except for the requirement on `daisy` and `peach` mainboards
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to include BL1 bootloader files from the vendor. These are:
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* HP Chromebook 11 G1 (daisy-spring) **(board removed from Libreboot, due to
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issues (will be re-added at a later date)**
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* Samsung Chromebook XE303 (daisy-snow) **(ditto)**
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* Samsung Chromebook 2 13” (peach-pi) **(ditto)**
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* Samsung Chromebook 2 11” (peach-pit) **(ditto)**
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* nyan-* chromebooks also temporarily removed, but are 100% free software in
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Libreboot
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List of vendor files, specifically for each board
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=================================================
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This article has thoroughly explained, in a detailed overview, the precise
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nature as to *what* vendor files are accomodated for in Libreboot. Again,
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fully libre init from coreboot is available *on all currently supported boards*.
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*From coreboot* is the critical aspect of this, but Libreboot's full scope is
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the main flash IC which (in some cases) contains software outside of coreboot.
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Here is a list, *for each* board, of those files:
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Intel/x86
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---------
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### Intel ME:
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Neutered ME required on these targets: `t420_8mb`, `t420s_8mb`, `t430_12mb`,
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`t440p_12mb`, `t440pmrc_12mb`, `t520_8mb`, `t530_12mb`, `w530_12mb`,
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`w541_12mb`, `w541mrc_12mb`, `x220_8mb`, `x230_12mb`, `x230_16mb`,
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`x230edp_12mb`, `x230t_12mb`, `x230t_16mb`, `hp8200sff`, `hp2560p_8mb`,
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`hp2570p_16mb`, `hp8300usdt_16mb`, `hp2170p_16mb`, `hp9470m_16mb`,
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`hp820g2_12mb` and `t1650_12mb`.
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As stated, Libreboot provides this in a state where the ME is no longer a
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threat to security. It initialises itself, but then does nothing, so it's
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disabled. This is done using `me_cleaner`. See:
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<https://github.com/corna/me_cleaner/wiki/How-does-it-work%3F>
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### KBC1126 EC firmware (HP laptops):
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This applies to the following targets: `hp2170p_16mb`, `hp2560p_8mb`,
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`hp2570p_16mb`, `hp8470pintel_16mb`, `hp9470m_16mb`.
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[EC firmware](faq.md#ec-embedded-controller-firmware)
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is inserted into main boot flash, rather than being on a separate
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IC. This is *better* because libre replacements would be more easy to install in
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the future, and reverse engineering is made much easier by it. Libreboot's
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build system handles such firmware in a script, automatically downloading
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it during the build process. Libreboot 20230423 onwards does scrub EC firmware
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and provide functionality in a special script, to insert them with `cbfstool`
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at the correct offset as defined by coreboot config for each board.
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### SMSC SCH5545 Environmental Control
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This is a tiny firmware required for fan control, on Dell Precision T1650.
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### CPU microcode:
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[*Microcode* updates](faq.md#microcode)
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for CPU provided on *all* x86 platforms, by default. Not
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technically required, but highly recommended. To remove, do:
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cbfstool filename.rom remove -n cpu_microcode_blob.bin
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On ASUS KFSN4-DRE, KCMA-D8 and KGPE-D16 boards, do this instead:
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cbfstool filename.rom remove -n microcode_amd.bin
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cbfstool filename.rom remove -n microcode_amd_fam15h.bin
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[Releases after Libreboot 20230423 will provide separate ROMs with microcode
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excluded, alongside default ones with microcode included.](news/microcode.md)
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Removal of microcode updates will affect system stability in a negative way,
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introducing non-standard broken behaviour and it may result in the machine
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being unable to boot properly. In other cases, doing so may break features such
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as S3 suspend/resume.
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CPU microcode files included by default, on all x86 boards. While not needed
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in most cases, their use is highly recommended. For reasons why, see:
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[news/policy.md#more-detailed-insight-about-microcode](news/policy.md#more-detailed-insight-about-microcode)
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### Intel Flash Descriptor (IFD):
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Intel Flash Descriptors are provided as blobs on some boards, but these are
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not *software* blobs. They are configurations provided in a binary format,
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fully readable by libre software. For example:
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* Libreboot's `ich9gen` program generates ICH9M flash descriptors from scratch.
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* Coreboot's `ifdtool` program has extensive features for manipulating Intel
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flash descriptors.
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* Corebot's `bincfg` program generates any sort of binary from a `.spec` file
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which can describe any binary format in a human readable format. It contains
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several flash descriptors for several platforms, but Libreboot does not use
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these.
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Intel GbE NVM config (configuration data, binary-encoded, for gigabit NIC):
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* Libreboot's `ich9gen` program *also* generates GbE NVM images specifically
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for Intel NICs used in GM45 thinkpads.
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* Libreboot's `nvmutil` program can manipulate GbE NVM images
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ARM/chromebooks
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---------------
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### BL1 bootloader (peach/daisy):
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BL1 bootloader needed on: `daisy_snow`, `daisy_spring` and `peach_pit`.
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These boards are *currently* not present. They were removed from Libreboot,
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because the build system does not yet auto-insert the BL1 files. The boards
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are otherwise believed to work, using Alper's port of U-Boot in Libreboot.
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Conclusion
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==========
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From the above, you can see that Libreboot really *does* implement a *binary
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blobs reduction policy*, with the emphasis on *reduction* being most critical.
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It can be asserted that Libreboot does in fact provide a reasonable level of
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*software freedom*, on all boards.
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Libreboot *could* add a lot more such files for many platforms, to enable various
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extra features, that it instead avoids adding, precisely because the *purpose*
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of the Libreboot project is to promote *libre* software and *minimise* the
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power that proprietary software developers have over users.
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I hope this article provided food for thought.
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An aside: hardware freedom
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--------------------------
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None of the currently supported Libreboot machines have libre *hardware*, in
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the sense that ICs do not come with publicly available *verilog* files and the
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like. You could not manufacture your own replacements of these machines.
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Some schematics and boardview files describing the circuit boards of each
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machine are available online, through various channels. You have to search for
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them yourself; one day, the Right To Repair movement will hopefully bring
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about universal access to such documents by the public.
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Further reading
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===============
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This article has described code what goes in the *main boot flash*, but any
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computer you buy will have *tons* of firmware elsewhere in the system. Some
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insights are available in the Libreboot FAQ. See:
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* [faq.md#what-level-of-software-freedom-does-libreboot-give-me](faq.md#what-level-of-software-freedom-does-libreboot-give-me)
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* [faq.md#what-other-firmware-exists-outside-of-libreboot](faq.md#what-other-firmware-exists-outside-of-libreboot)
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Of these, the most critical are HDD/SSD firmware and EC firmware. The problems
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described in those two links apply to many different computers, including
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Libreboot ones, and virtually every other computer in the world.
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