bare-metal-bringuplisted

# Bare-Metal Bring-Up ## Overview Bringing up code on new silicon or a new architecture is a sequence of "does the most basic thing work yet" checkpoints. Each layer has a small number of mistakes that produce total silence or a single cryptic fault, and they are almost always init ordering, trap setup, address translation, or ABI mismatches. **Core principle:** Get one character out the door first, then build up one checkpoint at a time. Until you have output, you are debugging blind, so the first job is always a working console, not the feature you wanted. ## When to Use - First boot on a new arch/board, or a port to a new target - "Boots but hangs," silent boot, or a fault before main - Traps/interrupts not firing, or firing into garbage - Syscalls returning wrong values or corrupting registers across the boundary - A driver works under one emulator/accelerator but not another (TCG vs KVM) ## The Checkpoint Ladder Climb in order. Don't debug a higher rung until the one below it is solid. 1. **Earliest output.** Poke the UART directly (no driver, no allocator). One known byte. If you can't get a byte, nothing else is debuggable. 2. **Stack and BSS.** A valid, correctly-placed stack and a zeroed BSS before any C/Zig/Rust runs. On some boots the stack must live inside a specific LOAD segment or the loader drops your initrd on top of it. 3. **Trap/exception vectors.** Install the vector table, prove it by taking a deliberate trap and returning. Get this working before