Stage 26

docs/README.md

@@ -22,6 +22,7 @@
 - `stage23.md`
 - `stage24.md`
 - `stage25.md`
+- `stage26.md`
 
 ## Notes
 - Stage docs use a fixed template: goal, implementation, acceptance criteria, build targets, QEMU command, and debugging notes.

docs/stage26.md

@@ -0,0 +1,37 @@
+# Stage 26 - Kernel Builtin ELF Loader + Root Hello ELF
+
+## Goal
+- Move `elfloader` from standalone user ELF into a kernel builtin command.
+- Keep `hello.elf` as root-level user ELF test payload.
+
+## Implementation
+- Removed standalone user app `elfloader_main.c`.
+- Added kernel shell builtin command: `elfloader [path]`.
+  - Default target path: `/hello.elf`.
+  - Builtin flow: `fs_read -> elf64 inspect -> exec load -> entry call -> return status`.
+- Updated CMake ramdisk placement rules:
+  - `hello.elf` -> `/hello.elf`
+- Simplified user Rust library back to shared helper export (`cleonos_rust_guarded_len`).
+
+## Acceptance Criteria
+- No `elfloader.elf` is generated or packed.
+- Ramdisk root contains `/hello.elf`.
+- In kernel shell:
+  - `elfloader` loads and executes `/hello.elf`, then returns status.
+  - `elfloader /path/to/app.elf` works for other absolute/relative paths.
+
+## Build Targets
+- `make userapps`
+- `make ramdisk`
+- `make iso`
+- `make run`
+
+## QEMU Command
+- `make run`
+
+## Debug Notes
+- If `elfloader` reports `file missing`, check ramdisk root packaging for `/hello.elf`.
+- If it reports `invalid elf64`, verify user app link script and ELF output format.
+- If it reports `exec failed`, inspect `EXEC` channel logs for load/entry/return status.
+- `hello.elf` is supported in current synchronous exec mode.
+- `/shell/shell.elf` is intentionally blocked in synchronous mode (interactive loop requires process/task context switching stage).