SchOS/boot/uefi
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Nexoniarz a1c965da1e include: one folder per subsystem, and includes that name it
Sixty-five headers sat side by side in include/, so `#include "irq.h"`
said nothing about where irq.h was or what it belonged to, and errno.h,
stat.h and fcntl.h at the top shadowed the system's for any host tool
built with -I./include. They are in folders now -- arch/ core/ fs/
dev/ gfx/ net/ uapi/ (and ldls/ for the Linux driver layer) -- and
every include names the folder, as Linux's do: "core/proc.h".

Done mechanically and checked the hard way: the kernel built from this
tree disassembles identically to the one built from the tree before
it. The full image boots, and userland is the same set of programs.
Paths in docs and comments follow; docs/guides/layout.md has a table
of what is where, and tools/fix-includes.py rewrites old-style
includes from the folders in the tree, for code written before this.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
2026-10-23 15:05:12 +02:00
..
efi.h hwreport: describe a machine onto a USB stick, from a Linux-style /sys 2026-10-23 12:54:11 +02:00
main.c include: one folder per subsystem, and includes that name it 2026-10-23 15:05:12 +02:00
README.md licence: SchOS is GPL-2.0-or-later, no longer Apache-2.0 2026-10-22 08:48:45 +02:00
startup.nsh boot/uefi: a working UEFI loader, with one known limitation 2026-08-09 17:13:09 +02:00

UEFI loader

The loader. This directory once existed only so the BIOS path could be moved into boot/bios/ without pretending the split was hypothetical; it is now the only path there is.

See ../README.md for the hand-off contract a loader has to satisfy. The short version: the kernel wants long mode with paging on, its ELF segments placed, a 24-byte-entry E820-shaped memory map, and framebuffer geometry — and it does not care which firmware produced them.

What this will need, in rough order:

  1. A PE/COFF target. clang can emit one directly (--target=x86_64-unknown-windows -fuse-ld=lld-link), so no new toolchain: the same LLVM install already builds every other target here.
  2. The handful of UEFI structures actually used — the system table, boot services, LOADED_IMAGE, SIMPLE_FILE_SYSTEM, GRAPHICS_OUTPUT. Written from the specification rather than by importing gnu-efi or EDK II, which is both a licence question and a large dependency for something this small.
  3. GetMemoryMap translated into the same 24-byte entries e820.c already parses. Not a second format for the kernel to learn.
  4. ExitBootServices before touching the memory it described.
  5. Graphics Output Protocol for the framebuffer, filling the same VBE_INFO_ADDR structure the kernel reads.

The image goes at EFI/BOOT/BOOTX64.EFI on a FAT ESP, which also means the ISO carries a single El Torito EFI entry.