universalisos/docs/T8-1.2g_WIRE_PERSONALITY_LOADER.md

T8-1.2g — Wire Personality Loader into Boot Path

Task: Wire the personality loader (T8-1.2c) into the actual boot path so it loads and boots the personality ELF instead of just pointing the vCPU at the entry point.

Current State:

• Personality loader exists (personality_loader.{h,cpp}) with ELF parsing, segment loading, and lifecycle management
• UOS_PERSONALITY_BOOT path in kernel_aarch64.cpp bypasses the loader and points vCPU directly at entry
• personality_boot() currently just sets state to RUNNING without creating a real task

Goal: Make the personality loader actually load the ELF and boot it as a proper UOS task.

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Path A: Direct Integration (Recommended)

Wire the personality loader into mp1_guest_setup() so it:

1. Creates a personality via personality_create()
2. Loads the ELF via personality_load_elf()
3. Configures it via personality_configure()
4. Boots it via personality_boot() (which creates the actual task)

Changes Required:

1. kernel_aarch64.cpp — mp1_guest_setup()

• Include personality_loader.h
• When UOS_PERSONALITY_BOOT is defined:
  • Call personality_manager_init()
  • Create personality: personality_create("gate_hmalloc", PERSONALITY_TYPE_MUSL)
  • Load ELF from QEMU_GUEST_BASE (where QEMU placed it)
  • Configure with default settings
  • Boot it (creates the vCPU/task)

2. personality_loader.cpp — personality_boot()

• Actually create a UOS task/vCPU instead of just setting state
• Call aarch64_vcpu_init() with the personality's entry point
• Call aarch64_vcpu_run() to start it

3. personality_loader.h

• Add function to get the vCPU for a personality (so the boot path can run it)

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Implementation Steps:

1. Add personality loader to boot path (kernel_aarch64.cpp)
2. Implement actual task creation in personality_boot()
3. Test build (compile for aarch64)
4. Test boot (QEMU with run-personality)

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Verification:

• Build succeeds for aarch64
• QEMU boots with personality
• Personality loader messages appear in UART output
• Gate test (hardened_malloc) runs successfully

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Files to Modify:

• kernel/src/arch/aarch64/kernel_aarch64.cpp — wire loader into boot path
• kernel/src/arch/aarch64/personality_loader.cpp — implement actual task creation
• kernel/src/arch/aarch64/personality_loader.h — add vCPU accessor

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Dependencies:

• T8-1.2c (personality loader) — DONE
• T8-1.2f (gate test ELF) — DONE
• aarch64 kernel build — needs to be fixed (task_context_t issue)

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Notes:

• The aarch64 kernel build is currently broken at HEAD (task_context_t typedef issue)
• This is a pre-existing issue from another session's refactor
• The personality loader files compile independently
• May need to fix the build issue first or work around it