43 lines
1.8 KiB
Markdown
43 lines
1.8 KiB
Markdown
# Payloads
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coreboot doesn't try to mandate how the boot process should look, it merely
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does hardware init and then passes on control to another piece of software
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that we carry along in firmware storage, the _payload_.
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There is various software in that space that is either explicitly written as
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payload or can be made to work as one.
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## SeaBIOS
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[SeaBIOS](https://www.seabios.org) is an open source implementation of
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the PCBIOS API that exists since the original IBM PC and was extended
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since. While originally written for emulators such as QEMU, it can be made
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to work as a coreboot payload and all the necessary code is in SeaBIOS'
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mainline code.
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## Tianocore
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[Tianocore](https://www.tianocore.org) is the open source reference
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implementation of the UEFI Specifications that modern firmware for PCs is
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based on. There were various projects in the past to make it suitable as a
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coreboot payload, but these days this function is available directly in the
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CorebootPayloadPkg part of its source tree.
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## GRUB2
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GRUB2 was originally written as a bootloader and that's its most popular
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purpose, but it can also be compiled as a coreboot payload.
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## Linux
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There are several projects using Linux as a payload (which was the
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configuration that gave coreboot its original name, LinuxBIOS). That kernel is
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often rather small and serves to load a current kernel from somewhere, e.g.
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disk or network, and run that through the kexec mechanism.
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Two aspects emphasized by proponents of Linux-as-a-payload are the
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availability of well-tested, battle-hardened drivers (as compared to
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firmware project drivers that often reinvent the wheel) and the ability to
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define boot policy with familiar tools, no matter if those are shell scripts
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or compiled userland programs written in C, Go or other programming languages.
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