                   _    _                 _
                  | |  | |               | |
                  | |__| | __ _ _ __   __| | _____   _____ _ __
                  |  __  |/ _` | '_ \ / _` |/ _ \ \ / / _ \ '__|
                  | |  | | (_| | | | | (_| | (_) \ V /  __/ |
                  |_|  |_|\__,_|_| |_|\__,_|\___/ \_/ \___|_|

                     A simple and extensible boot protocol

Design Goals

One contiguous area of memory makes it easy to hand it around.
Easy to parse using on contiguous array of records.
Centered around the memory map
No callbacks, no state.

Overview

Handover Request

struct HandoverRequest
{
    uint32_t tag;
    uint32_t flags;
    uint64_t more;
};

Handover Payload

struct HandoverPayload
{
    uint32_t magic, agent, size, count;
    HandoverRecord records[];
};


struct HandoverRecord
{
    uint32_t tag;
    uint32_t flags;
    uint64_t start;
    uint64_t size;
    uint64_t more;
};

Machine State

Except what stated bellow the machine state is undefined.

x86_64

rdi: will contain the 0xc001b001 magic number
rsi: will contain the address of the handover payload in the kernel space

Paging is enabled and the following ranges are mapped

Some LOADER regions are mapped to the same physical memory address for the initial spinup
The first 4gio at 0xffffffff80000000 refered as I/O space
KERNEL, STACK and SELF regions are mapped at 0xffff800000000000 and are refered as kernel space.