https://github.com/blitz/bender

A multiboot chainloader that makes PCI serial cards available for legacy use
https://github.com/blitz/bender

multiboot serial x86

Last synced: 1 day ago
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A multiboot chainloader that makes PCI serial cards available for legacy use

• Host: GitHub
• URL: https://github.com/blitz/bender
• Owner: blitz
• License: gpl-2.0
• Created: 2019-12-11T15:37:51.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2023-07-14T22:16:37.000Z (over 1 year ago)
• Last Synced: 2023-07-14T23:24:41.618Z (over 1 year ago)
• Topics: multiboot, serial, x86
• Language: C
• Size: 479 KB
• Stars: 4
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Bender

![GitHub](https://img.shields.io/github/license/blitz/bender)

Bender is a

[Multiboot](https://www.gnu.org/software/grub/manual/multiboot/multiboot.html)

chainloader intended to be loaded from Grub or a similar

multiboot-capable boot loader. It tries to find PCI serial controllers

and updates the [BIOS Data

Area](https://wiki.osdev.org/BDA#BIOS_Data_Area_.28BDA.29) to make

them discoverable by legacy software.

Additionally, bender will move modules to a higher location in

physical memory to avoid clashes when ELFs are unpacked.

## Building with Nix (Recommended)

Get [Nix](https://nixos.org/nix/) and type:

```sh

% nix-build

```

You can find `bender` in `result/`.

If you have a [Flakes-enabled Nix](https://nixos.wiki/wiki/Flakes),

try out `nix build` to build bender and `nix flake check` to run its

tests.

## Building without Nix

Be sure to have [CMake](https://cmake.org/install/) and a C toolchain

installed. Afterwards, you can build the source code via:

```sh

% mkdir -p build

% cd build

% cmake ..

% make

```

You will find `bender` in `standalone/` in your build directory.

# Usage

Check the documentation of your Multiboot-capable boot loader to see

how Bender is booted. Bender will discover serial ports and then boot

the next boot module as Multiboot2 or Multiboot1 kernel depending on

what it supports.

## Parameters

Bender supports the following command-line parameters:

- `promisc`: Be more forgiving which PCI serial controller to

  accept. Specifically, this makes Bender claim any PCI device with

  "Simple Communication Controller" PCI class and not only those

  claiming to be a legacy serial controller. This is typically needed

  for some multiport PCI serial adapters.

- `accept_legacy`: Don't claim a PCI serial controller, if the BIOS

  already indicates that there is a legacy serial controller

  available.

- `phys_max=256M` (literally only that specific string): Prevent

  bender from relocating modules past 256M in the physical address

  space.