native_rpi5_entry.S: Pi 5 native (non-UEFI) boot entry stub (FABRIC-3.md §IV.3 item 1)

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rpi5_native_start masks x0 down to the documented 32-bit DTB-pointer range
(the firmware's own entry protocol leaves the upper 32 bits unspecified),
stores it into g_rpi5_dtb_ptr for the still-open DTB->BootInfo constructor
(item 2) to read, then switches sp to a dedicated 2 MiB BSS stack -- this
path has no EDK2 boot stack to inherit, unlike every other entry path in
this codebase.

Intentionally halts (wfe/b loop) afterward rather than tail-calling into
item 2's constructor, which doesn't exist yet -- no stub function pretending
to be more than it is.

Not yet linked at the real 0x80000 load address; that needs its own linker
script/build target, not scoped into this item. Compiles and links into the
existing ARCH=aarch64 QEMU/UEFI acceptance build as dead code (ELF kernel
build's KERNEL_ASM wildcards every *.S in arch/aarch64/; nothing there
branches to it), same as rpi5_dtb.c/rpi5_mailbox.c before it.

Verified 3-arch boot to ok>/zuse)ok>.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019YcT3H2PQeyujrzjqS3Var

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This commit is contained in:

Robert Allan James

2026-09-04 14:12:42 -04:00

co-authored by Claude Sonnet 5

parent a32b0ebcbe

commit 281de9547c

11 changed files with 27695 additions and 5 deletions

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experiments/bare_metal/runs/doe-aarch64-20260904-140833.csv

experiments/bare_metal/runs/doe-amd64-20260904-140713.csv

experiments/bare_metal/runs/doe-riscv64-20260904-141114.csv