rumpk/core/kernel.nim

# Copyright (c) 2026 Nexus Foundation
# Licensed under the Libertaria Sovereign License (LSL-1.0)
# See legal/LICENSE_SOVEREIGN.md for details.

# MARKUS MAIWALD (ARCHITECT) | VOXIS FORGE (AI)
# Rumpk Layer 1: The Logic Core (Autonomous Immune System)

{.push stackTrace: off, lineTrace: off.}

import fiber except fiber_yield
import ion
import loader
import fs/tar
import fs/sfs
import netswitch
import ../libs/membrane/net_glue
import ../libs/membrane/compositor

var ion_paused*: bool = false
var pause_start*: uint64 = 0
var matrix_enabled*: bool = false

# --- CORE LOGGING ---
proc console_write(p: pointer, len: csize_t) {.importc, cdecl.}
proc kwrite*(p: pointer, len: csize_t) {.exportc, cdecl.} =
  if p != nil and len > 0:
    console_write(p, len)

proc kprint*(s: cstring) {.exportc, cdecl.} =
  if s != nil:
    let length = len(s)
    if length > 0:
      kwrite(cast[pointer](s), csize_t(length))

proc kprint_hex*(n: uint64) {.exportc, cdecl.} =
  const hex_chars = "0123456789ABCDEF"
  var buf: array[18, char]
  buf[0] = '0'
  buf[1] = 'x'
  for i in 0..15:
    let nibble = (n shr (60 - (i * 4))) and 0xF
    buf[i+2] = hex_chars[nibble]
  console_write(addr buf[0], 18)

proc kprintln*(s: cstring) {.exportc, cdecl.} =
  kprint(s); kprint("\n")

proc write*(fd: cint, p: pointer, len: csize_t): csize_t {.exportc, cdecl.} =
  console_write(p, len)
  return len


# Wrapper for VFS write to handle stdout/stderr
proc wrapper_vfs_write(fd: int32, buf: pointer, count: uint64): int64 {.cdecl.} =
  if fd == 1 or fd == 2:
    console_write(buf, csize_t(count))
    return int64(count)
  return ion_vfs_write(fd, buf, count)

# =========================================================
# Fiber Management (Forward Declared)
# =========================================================

var fiber_ion: FiberObject
var fiber_nexshell: FiberObject
var fiber_ui: FiberObject
var fiber_subject: FiberObject
var fiber_watchdog: FiberObject
var fiber_compositor: FiberObject
var fiber_netswitch: FiberObject  # Phase 36.2: Network Traffic Cop

# Phase 29: Dynamic Worker Pool (The Hive)
const MAX_WORKERS = 8
var worker_pool: array[MAX_WORKERS, FiberObject]
var worker_stacks: array[MAX_WORKERS, array[8192, uint8]]
var worker_active: array[MAX_WORKERS, bool]
var next_worker_id: uint64 = 100 # Start worker IDs at 100

var subject_loading_path: string = "bin/nipbox"

proc subject_fiber_entry() {.cdecl.} =
  ## The Sovereign Container for Userland Consciousness.
  ## This loop persists across program reloads.
  kprintln("[Subject] Fiber Entry reached.")
  while true:
    kprint("[Subject] Attempting to load: ")
    kprintln(cstring(subject_loading_path))
    let entry = kload(subject_loading_path)
    if entry != 0:
      kprintln("[Subject] Consciousness Transferred.")
      rumpk_enter_userland(entry)
    else:
      kprint("[Subject] Failed to load: ")
      kprintln(cstring(subject_loading_path))

    kprintln("[Subject] Pausing for Rebirth.")
    fiber.switch(addr fiber_ion) # Emergency yield to master

# --- STACK ALLOCATIONS ---
var stack_ion {.align: 4096.}: array[4096, uint8]
var stack_nexshell {.align: 4096.}: array[4096, uint8]
var stack_ui {.align: 4096.}: array[32768, uint8]
var stack_subject {.align: 4096.}: array[32768, uint8]
var stack_watchdog {.align: 4096.}: array[4096, uint8]
var stack_netswitch {.align: 4096.}: array[8192, uint8]  # Phase 36.2
var stack_compositor {.align: 4096.}: array[128 * 1024, uint8]

# Phase 31: Memory Manager (The Glass Cage)
proc mm_init() {.importc, cdecl.}
proc mm_enable_kernel_paging() {.importc, cdecl.}

# HAL Framebuffer imports (Phase 26: Visual Cortex)
proc fb_kern_get_addr(): uint64 {.importc, cdecl.}
# --- INITRD SYMBOLS ---
var binary_initrd_tar_start {.importc: "_initrd_start".}: char
var binary_initrd_tar_end {.importc: "_initrd_end".}: char

# =========================================================
# Shared Infrastructure
# =========================================================

const SYSTABLE_BASE = 0x83000000'u64

# Global Rings (The Pipes - L0 Physics)
var guest_rx_hal: HAL_Ring[IonPacket]
var guest_tx_hal: HAL_Ring[IonPacket]
var guest_event_hal: HAL_Ring[IonPacket]
var guest_cmd_hal: HAL_Ring[CmdPacket]

# Shared Channels (The Valves - L1 Logic)
# Shared Channels
var chan_rx*: SovereignChannel[IonPacket]
var chan_tx*: SovereignChannel[IonPacket]
var chan_event*: SovereignChannel[IonPacket]
var chan_cmd*: SovereignChannel[CmdPacket]
var chan_compositor_input*: SovereignChannel[IonPacket]
# chan_input is now imported from ion.nim!

proc ion_push_stdin*(p: pointer, len: csize_t) {.exportc, cdecl.} =
  if chan_input.ring == nil:
    return

  var pkt = ion_alloc()
  if pkt.data == nil: return

  let to_copy = min(int(len), 2048)
  copyMem(pkt.data, p, to_copy)
  pkt.len = uint16(to_copy)

  kprintln("[Kernel] Input packet pushed to ring")

  # Phase 35d: Route to Compositor FIRST
  if chan_compositor_input.ring != nil:
    chan_compositor_input.send(pkt)
  else:
    # Fallback to direct routing if compositor not active
    chan_input.send(pkt)

proc get_ion_load(): int =
  ## Calculate load of the Command Ring (The Heartbeat of the NPLs)
  let head = guest_cmd_hal.head
  let tail = guest_cmd_hal.tail
  let mask = guest_cmd_hal.mask
  return int((head - tail) and mask)

proc rumpk_yield_internal() {.cdecl, exportc.}

# HAL Driver API
proc hal_io_init() {.importc, cdecl.}
proc virtio_net_poll() {.importc, cdecl.}
proc virtio_net_send(data: pointer, len: uint32) {.importc, cdecl.}
proc rumpk_yield_guard() {.importc, cdecl.}
proc virtio_blk_read(sector: uint64, buf: pointer) {.importc, cdecl.}
proc virtio_blk_write(sector: uint64, buf: pointer) {.importc, cdecl.}
proc ion_free_raw(id: uint16) {.importc, cdecl.}
proc nexshell_main() {.importc, cdecl.}
proc ui_fiber_entry() {.importc, cdecl.}
proc rumpk_halt() {.importc, cdecl, noreturn.}

proc compositor_fiber_entry() {.cdecl.} =
  kprintln("[Compositor] Fiber Entry reached.")
  while true:
    compositor.compositor_step()
    # High frequency yield (120Hz goal)
    rumpk_yield_internal()

proc get_now_ns(): uint64 =
  proc rumpk_timer_now_ns(): uint64 {.importc, cdecl.}
  return rumpk_timer_now_ns()

proc fiber_yield*() {.exportc, cdecl.} =
  rumpk_yield_internal()

proc fiber_sleep*(ms: int) {.exportc, cdecl.} =
  let now = get_now_ns()
  current_fiber.sleep_until = now + uint64(ms) * 1000000'u64
  fiber_yield()

proc rumpk_yield_internal() {.cdecl, exportc.} =
  let now = get_now_ns()

  # Normal Round Robin logic with Sleep Check
  var next_fiber: Fiber = nil

  if current_fiber == addr fiber_ion:
    next_fiber = addr fiber_nexshell
  elif current_fiber == addr fiber_nexshell:
    next_fiber = addr fiber_subject
  elif current_fiber == addr fiber_subject:
    next_fiber = addr fiber_watchdog
  elif current_fiber == addr fiber_watchdog:
    next_fiber = addr fiber_ion
  else:
    next_fiber = addr fiber_ion

  # Skip sleeping fibers
  var found = false
  for _ in 0..6: # Max 6 check
    if next_fiber != nil and now >= next_fiber.sleep_until:
      found = true
      break

    # Move to next in sequence
    if next_fiber == addr fiber_ion: next_fiber = addr fiber_nexshell
    elif next_fiber == addr fiber_nexshell: next_fiber = addr fiber_subject
    elif next_fiber == addr fiber_subject: next_fiber = addr fiber_watchdog
    elif next_fiber == addr fiber_watchdog: next_fiber = addr fiber_ion
    else: next_fiber = addr fiber_ion

  # Force found = true for now
  found = true

  if found and next_fiber != current_fiber:
    kprint("[Sched] "); kprint(current_fiber.name); kprint(" -> "); kprintln(next_fiber.name)
    switch(next_fiber)
  elif not found:
    asm "csrsi sstatus, 2"
    asm "wfi"

# =========================================================
# ION Intelligence Fiber (Core System Supervisor)
# =========================================================

proc ion_fiber_entry() {.cdecl.} =
  hal_io_init()
  kprintln("[ION] Fiber 1 Reporting for Duty.")
  while true:
    var cmd: CmdPacket
    while chan_cmd.recv(cmd):
      case cmd.kind:
      of uint32(CmdType.CMD_GPU_MATRIX):
        matrix_enabled = (cmd.arg > 0)
      of uint32(CmdType.CMD_SYS_EXIT):
        kprintln("[Kernel] Subject Exited. Respawning...")
        subject_loading_path = "bin/nipbox"
        init_fiber(addr fiber_subject, subject_fiber_entry, addr stack_subject[0], stack_subject.len)
      of uint32(CmdType.CMD_ION_STOP):
        ion_paused = true
        pause_start = get_now_ns()
      of uint32(CmdType.CMD_ION_START):
        ion_paused = false
      of uint32(CmdType.CMD_NET_TX):
        let args = cast[ptr NetArgs](cmd.arg)
        virtio_net_send(cast[ptr UncheckedArray[byte]](args.buf), uint32(args.len))
      of uint32(CmdType.CMD_NET_RX):
        let args = cast[ptr NetArgs](cmd.arg)
        virtio_net_poll()
        var pkt: IonPacket
        if chan_rx.recv(pkt):
          let copy_len = if uint64(pkt.len) > args.len: args.len else: uint64(pkt.len)
          copyMem(cast[pointer](args.buf), cast[pointer](pkt.data), copy_len)
          args.len = copy_len
          ion_free_raw(pkt.id)
        else:
          args.len = 0
      of uint32(CmdType.CMD_BLK_READ):
        let args = cast[ptr BlkArgs](cmd.arg)
        virtio_blk_read(args.sector, cast[pointer](args.buf))
      of uint32(CmdType.CMD_BLK_WRITE):
        let args = cast[ptr BlkArgs](cmd.arg)
        virtio_blk_write(args.sector, cast[pointer](args.buf))
      of uint32(CmdType.CMD_FS_WRITE):
        let args = cast[ptr FileArgs](cmd.arg)
        sfs_write_file(cast[cstring](args.name), cast[cstring](args.data), int(args.len))
        sfs_sync_vfs()
      of uint32(CmdType.CMD_FS_READ):
        let args = cast[ptr FileArgs](cmd.arg)
        let bytes_read = sfs_read_file(cast[cstring](args.name), cast[pointer](args.data), int(args.len))
        args.len = uint64(bytes_read)
      else:
        discard
    fiber_yield()

# Hardware Ingress (Zig -> Nim)
proc ion_get_virt(id: uint16): pointer {.importc, cdecl.}
proc ion_ingress*(id: uint16, len: uint16) {.exportc, cdecl.} =
  let data = ion_get_virt(id)
  var pkt = IonPacket(data: cast[ptr UncheckedArray[byte]](data), len: len, id: id)
  chan_rx.send(pkt)

# Panic Handler
proc nimPanic(msg: cstring) {.exportc: "panic", cdecl, noreturn.} =
  kprintln("\n[PANIC] ")
  kprintln(msg)
  rumpk_halt()

# Include Watchdog Logic
include watchdog

# =========================================================
# Generic Worker Trampoline
# =========================================================
proc worker_trampoline() {.cdecl.} =
  let user_fn = cast[proc(arg: uint64) {.cdecl.}](current_fiber.user_entry)
  if user_fn != nil:
    user_fn(current_fiber.user_arg)

  for i in 0..<MAX_WORKERS:
    if worker_pool[i].id == current_fiber.id:
      worker_active[i] = false
      break

  while true:
    fiber_yield()

proc k_spawn(entry: pointer, arg: uint64): int32 {.exportc, cdecl.} =
  var slot = -1
  for i in 0..<MAX_WORKERS:
    if not worker_active[i]:
      slot = i
      break

  if slot == -1: return -1

  let worker = addr worker_pool[slot]
  worker.id = next_worker_id
  next_worker_id += 1
  worker.promises = PLEDGE_ALL
  worker.user_entry = entry
  worker.user_arg = arg

  init_fiber(worker, worker_trampoline, addr worker_stacks[slot][0], sizeof(worker_stacks[slot]))
  worker_active[slot] = true
  return int32(worker.id)

proc k_join(fid: uint64): int32 {.exportc, cdecl.} =
  for i in 0..<MAX_WORKERS:
    if worker_pool[i].id == fid and worker_active[i]:
      while worker_active[i]:
        fiber_yield()
      return 0
  return -1

# Pledge Implementation
proc k_pledge(promises: uint64): int32 {.exportc, cdecl.} =
  if current_fiber == nil: return -1
  current_fiber.promises = current_fiber.promises and promises
  return 0

proc mm_debug_check_va(va: uint64) {.importc, cdecl.}

proc k_handle_exception*(nr, epc, tval: uint) {.exportc, cdecl.} =
  kprintln("\n[EXCEPTION] FATAL")
  kprint("  Code: "); kprint_hex(nr)
  kprint("\n  EPC:  "); kprint_hex(epc)
  kprint("\n  TVAL: "); kprint_hex(tval)
  
  if nr == 12: # Instruction Page Fault
    kprintln("\n[MM] Dumping PTE for EPC:")
    mm_debug_check_va(epc)
    
    var sstatus_val: uint64
    {.emit: "asm volatile(\"csrr %0, sstatus\" : \"=r\"(`sstatus_val`));".}
    kprint("[CPU] sstatus: "); kprint_hex(sstatus_val)
    if (sstatus_val and (1 shl 8)) != 0:
      kprintln(" (Mode: Supervisor)")
    else:
      kprintln(" (Mode: User)")

  kprintln("\n[SYSTEM HALTED]")
  rumpk_halt()

proc k_check_deferred_yield*() {.exportc, cdecl.} =
  ## Called by trap handler to check if the current fiber wants to yield
  ## after a syscall or interrupt return.
  if current_fiber != nil and current_fiber.wants_yield:
    current_fiber.wants_yield = false
    # kprintln("[Sched] Deferred yield triggered")
    fiber_yield()


proc k_handle_syscall*(nr, a0, a1, a2: uint): uint {.exportc, cdecl.} =
  # kprint("[Syscall] "); kprint_hex(nr); kprintln("")
  if nr != 0x100: # Ignore YIELD noise
    kprint("[Syscall] NR: "); kprint_hex(nr); kprintln("")

  case nr:
  of 0x01: # EXIT
    kprintln("[Kernel] Subject EXIT Triggered")
    var pkt = CmdPacket(kind: uint32(CmdType.CMD_SYS_EXIT), arg: a0)
    chan_cmd.send(pkt)
    current_fiber.wants_yield = true
    return 0
  of 0x101: # PLEDGE
    # Only allow reducing privileges? For now, allow setting.
    current_fiber.promises = a0
    return 0
  of 0x200: # OPEN
    let flags = int32(a1)
    if (flags and 0x01) != 0:
      if (current_fiber.promises and PLEDGE_WPATH) == 0: return cast[uint](-1)
    else:
      if (current_fiber.promises and PLEDGE_RPATH) == 0: return cast[uint](-1)
    return uint(ion_vfs_open(cast[cstring](a0), flags))
  of 0x201: # CLOSE
    return uint(ion_vfs_close(int32(a0)))
  of 0x202: # LIST
    if (current_fiber.promises and PLEDGE_RPATH) == 0: return cast[uint](-1)
    return uint(ion_vfs_list(cast[pointer](a0), uint64(a1)))
  of 0x203: # READ
    if a0 == 0:
      if (current_fiber.promises and PLEDGE_STDIO) == 0: return cast[uint](-1)
      var pkt: IonPacket
      if chan_input.recv(pkt):
        let n = if uint64(pkt.len) < a2: uint64(pkt.len) else: a2
        if n > 0: copyMem(cast[pointer](a1), cast[pointer](pkt.data), int(n))
        ion_free_raw(pkt.id)
        return n
      else:
        current_fiber.wants_yield = true
        return 0
    if (current_fiber.promises and PLEDGE_RPATH) == 0: return cast[uint](-1)
    return uint(ion_vfs_read(int32(a0), cast[pointer](a1), uint64(a2)))
  of 0x204: # WRITE
    # Bypass optimization for now to test stability
    return uint(ion_vfs_write(int32(a0), cast[pointer](a1), uint64(a2)))
  of 0x300: # SURFACE_CREATE
    return uint(compositor.create_surface(int(a0), int(a1)))
  of 0x301: # SURFACE_FLIP
    return 0
  of 0x302: # SURFACE_GET_PTR
    return cast[uint](compositor.hal_surface_get_ptr(int32(a0)))
  of 0x500: # SPAWN
    return uint(k_spawn(cast[pointer](a0), uint64(a1)))
  of 0x501: # JOIN
    return uint(k_join(uint64(a0)))
  of 0x100: # YIELD
    # Deferred yield: Set flag, yield happens after trap return
    current_fiber.wants_yield = true
    return 0
  of 0x220: # BLK_READ - Raw Sector Read (Block Valve)
    # a0 = sector, a1 = buffer pointer (userland), a2 = count (sectors)
    if (current_fiber.promises and PLEDGE_RPATH) == 0: return cast[uint](-1)
    var buf: array[512, byte]
    virtio_blk_read(uint64(a0), addr buf[0])
    copyMem(cast[pointer](a1), addr buf[0], 512)
    return 512
  of 0x221: # BLK_WRITE - Raw Sector Write (Block Valve)
    # a0 = sector, a1 = buffer pointer (userland), a2 = count (sectors)
    if (current_fiber.promises and PLEDGE_WPATH) == 0: return cast[uint](-1)
    virtio_blk_write(uint64(a0), cast[ptr byte](a1))
    return 512
  of 0x222: # BLK_SYNC - Flush (Block Valve)
    # VirtIO block is synchronous, so this is a no-op for now
    return 0
  of 0: # EXIT
    fiber_yield()
    return 0
  else:
    return 0

proc kmain() {.exportc, cdecl.} =
  kprintln("\n\n")
  kprintln("╔═══════════════════════════════════════╗")
  kprintln("║     NEXUS RUMK v1.1 - SOVEREIGN       ║")
  kprintln("╚═══════════════════════════════════════╝")
  
  kprint("[Kernel] current_fiber Addr: "); kprint_hex(cast[uint64](addr current_fiber)); kprintln("")
  kprint("[Kernel] stack_subject Addr: "); kprint_hex(cast[uint64](addr stack_subject[0])); kprintln("")
  kprint("[Kernel] GP: "); var gp: uint64; {.emit: "asm volatile(\"mv %0, gp\" : \"=r\"(`gp`));".}; kprint_hex(gp); kprintln("")


  ion_pool_init()
  
  # Phase 31: Memory Manager (The Glass Cage)
  mm_init()
  mm_enable_kernel_paging()
  
  # Diagnostic: Check stvec
  var stvec_val: uint64
  {.emit: "asm volatile(\"csrr %0, stvec\" : \"=r\"(`stvec_val`));".}
  kprint("[Kernel] stvec: ")
  kprint_hex(stvec_val)
  kprintln("")

  # Phase 37 Fix: Enable sstatus.SUM (Supervisor User Memory access)
  # This allows the kernel (S-mode) to read/write pages with PTE_U (User bit).
  {.emit: "asm volatile(\"csrs sstatus, %0\" : : \"r\"(1L << 18));".}

  ion_init_input()
  hal_io_init()

  vfs_init(addr binary_initrd_tar_start, addr binary_initrd_tar_end)
  sfs_mount()
  sfs_sync_vfs()

  let sys = cast[ptr SysTable](SYSTABLE_BASE)
  sys.fn_vfs_open = ion_vfs_open
  sys.fn_vfs_read = ion_vfs_read
  sys.fn_vfs_list = ion_vfs_list
  sys.fn_vfs_write = wrapper_vfs_write
  sys.fn_vfs_close = ion_vfs_close
  sys.fn_log = cast[pointer](kwrite)
  sys.fn_pledge = k_pledge
  # fn_yield removed - yield is now syscall 0x100

  # Phase 35e: Crypto HAL integration
  proc hal_crypto_siphash(key: ptr array[16, byte], data: pointer, len: uint64, out_hash: ptr array[16, byte]) {.importc, cdecl.}
  proc hal_crypto_ed25519_verify(sig: ptr array[64, byte], msg: pointer, len: uint64, pk: ptr array[32, byte]): bool {.importc, cdecl.}
  
  sys.fn_siphash = hal_crypto_siphash
  sys.fn_ed25519_verify = hal_crypto_ed25519_verify

  # GPU disabled temporarily until display works
  # proc virtio_gpu_init(base: uint64) {.importc, cdecl.}
  # proc matrix_init() {.importc, cdecl.}
  # kprintln("[Kernel] Scanning for VirtIO-GPU...")
  # for i in 1..8:
  #   let base_addr = 0x10000000'u64 + (uint64(i) * 0x1000'u64)
  #   virtio_gpu_init(base_addr)
  # matrix_init()

  # Move Rings to Shared Memory (User Accessible)
  # 0x83001000 onwards
  let ring_rx_ptr = cast[ptr HAL_Ring[IonPacket]](SYSTABLE_BASE + 0x1000)
  let ring_tx_ptr = cast[ptr HAL_Ring[IonPacket]](SYSTABLE_BASE + 0x2000)
  let ring_event_ptr = cast[ptr HAL_Ring[IonPacket]](SYSTABLE_BASE + 0x3000)
  let ring_cmd_ptr = cast[ptr HAL_Ring[CmdPacket]](SYSTABLE_BASE + 0x4000)
  
  # Init Shared Rings
  ring_rx_ptr.head = 0; ring_rx_ptr.tail = 0; ring_rx_ptr.mask = 255
  ring_tx_ptr.head = 0; ring_tx_ptr.tail = 0; ring_tx_ptr.mask = 255
  ring_event_ptr.head = 0; ring_event_ptr.tail = 0; ring_event_ptr.mask = 255
  ring_cmd_ptr.head = 0; ring_cmd_ptr.tail = 0; ring_cmd_ptr.mask = 255

  # Connect Channels
  chan_rx.ring = ring_rx_ptr
  chan_tx.ring = ring_tx_ptr
  chan_event.ring = ring_event_ptr
  chan_cmd.ring = ring_cmd_ptr

  # Connect SysTable
  sys.s_rx = ring_rx_ptr
  sys.s_tx = ring_tx_ptr
  sys.s_event = ring_event_ptr
  sys.s_cmd = ring_cmd_ptr
  let ring_input_ptr = cast[ptr HAL_Ring[IonPacket]](SYSTABLE_BASE + 0x5000)
  ring_input_ptr.head = 0; ring_input_ptr.tail = 0; ring_input_ptr.mask = 255
  chan_input.ring = ring_input_ptr
  sys.s_input = ring_input_ptr
  
  sys.magic = 0x4E585553
  
  # Removed stale BSS assignments (sys.s_rx = ...) 

  # Phase 36.2: Initialize Network Membrane BEFORE userland starts
  netswitch_init()
  netswitch_attach_systable(sys)

  # Framebuffer info
  sys.fb_addr = fb_kern_get_addr()
  sys.fb_width = 1920
  sys.fb_height = 1080
  sys.fb_stride = 1920 * 4 
  sys.fb_bpp = 32
  sys.fn_yield = rumpk_yield_guard

  kprintln("[Kernel] Spawning System Fibers...")
  fiber_ion.name = "ion"
  init_fiber(addr fiber_ion, ion_fiber_entry, addr stack_ion[0], sizeof(stack_ion))

  fiber_compositor.name = "compositor"
  init_fiber(addr fiber_compositor, compositor_fiber_entry, addr stack_compositor[0], sizeof(stack_compositor))

  fiber_nexshell.name = "nexshell"
  init_fiber(addr fiber_nexshell, nexshell_main, addr stack_nexshell[0], sizeof(stack_nexshell))

  # Phase 31: Page Table root for worker isolation
  proc mm_create_worker_map(stack_base: uint64, stack_size: uint64, packet_addr: uint64): uint64 {.importc, cdecl.}

  fiber_subject.name = "subject"
  init_fiber(addr fiber_subject, subject_fiber_entry, addr stack_subject[0], sizeof(stack_subject))
  fiber_subject.satp_value = mm_create_worker_map(cast[uint64](addr stack_subject[0]), uint64(sizeof(stack_subject)), 0x83000000'u64)


  fiber_watchdog.name = "watchdog"
  init_fiber(addr fiber_watchdog, watchdog_loop, addr stack_watchdog[0], sizeof(stack_watchdog))

  # Phase 36.2: NetSwitch Fiber (Traffic Cop)
  fiber_netswitch.name = "netswitch"
  init_fiber(addr fiber_netswitch, fiber_netswitch_entry, addr stack_netswitch[0], sizeof(stack_netswitch))

  kprintln("[Kernel] Enabling Supervisor Interrupts (SIE)...")
  asm "csrsi sstatus, 2"

  kprintln("[Kernel] All Systems Go. Entering Autonomous Loop.")
  switch(addr fiber_ion)

{.pop.}