isolate POSIX builds from the host UCRT, wire lwext4 and ntfs-3g as ext4.sys and ntfs.sys, split the FAT driver into directory/file/async/driver/mount units, add posixsrv and dwm plus input/console/desktop syscall clients and a pile of new smoke targets, rename serial.sys to cereal.sys, name HDA/USB/lwIP/AHCI workers, harden ATA probing/reset/removal around actual hardware deadlines, absent-channel detection, diagnostics and explicit worker lifetime, redo ACPI S5 shutdown around GAS/MMIO and HW-reduced firmware, scan SSDTs for _S5 and deal with Intel SMI sleep trapping, make serial and SMP timeouts use real monotonic deadlines, add thread names and fix terminal thread teardown, scheduler and APC prepare/commit races, make advisory file locks queryable and preserve split ranges and add mutable file append state, add shared-memory pipes with kernel-assisted wait/wake, introduce capability-scoped input and display managers, split surface map rights into read/write, add explicit unmap and replace present with commit/generation/damage tracking while keeping physical presentation under the display manager, decouple native exception classes from Win32 exception numbers and translate them in kernel32, add opaque process startup data, bump the resource protocol to v3 with namespace directories, symlinks and enumeration and service control to v2 with generic READY handle exports, add the new POSIX errno/status surface and rebuild fds around posixsrv-owned shared open descriptions, descriptor-local flags, exact inheritance snapshots, dup/fcntl/record locks and shared-ring pipes, add waitpid, POSIX credentials/groups/sessions/passwd/group lookups and move sockets onto stable open descriptions, port the shells and apps to the new console/input services and surface commit API, teach init to load services.ini and start/supervise RSSRV, DWM and generic services under restricted capabilities while publishing their endpoints through RSSRV, split RSSRV into namespace, volume, display, session, input, console and resource components and make /SystemRoot a real symlink to the independently published system volume, shift the syscall table again, expand lock/resource/surface/POSIX/service/thread smoke coverage, make docs scream ASK QUESTIONS and DISCUSS at LLMs, replace MIT No Attribution with WTFPL+.

code/kernel/hal/hal_serial.c

@@ -6,13 +6,16 @@
 #include <kernel/hal/hal_api.h>
 #include <kernel/hal/hal_output.h>
 #include <kernel/hal/hal_processor.h>
+#include <kernel/hal/hal_timer.h>
 
 #define HAL_COM1_BASE             0x03F8u
 #define HAL_COM1_DATA_PORT        (HAL_COM1_BASE + 0u)
 #define HAL_COM1_STATUS_PORT      (HAL_COM1_BASE + 5u)
 #define HAL_COM1_SCRATCH_PORT     (HAL_COM1_BASE + 7u)
 #define HAL_COM1_TX_READY         0x20u
-#define HAL_SERIAL_TX_SPIN_LIMIT  1000000u
+#define HAL_SERIAL_TX_TIMEOUT_US  2000u
+#define HAL_SERIAL_TIMER_SPIN_CAP 65536u
+#define HAL_SERIAL_EARLY_SPINS     4096u
 
 static volatile long gSerialWriteLock;
 static volatile long gSerialPresent;
@@ -30,9 +33,25 @@ static bool HalSerialProbeCom1(void) {
     return first == 0x5Au && second == 0xA5u;
 }
 
-// Waits for COM1 transmit readiness without allowing broken or removed hardware to stall the machine forever.
+// Waits for COM1 transmit readiness with a real microsecond deadline once the HAL timer is live.
 static bool HalSerialWaitForTransmit(void) {
-    for (uint32_t spin = 0; spin < HAL_SERIAL_TX_SPIN_LIMIT; spin++) {
+    uint64_t start = HalTimerQueryTicks();
+    if (start != 0) {
+        uint64_t deadline = start > UINT64_MAX - HAL_SERIAL_TX_TIMEOUT_US
+            ? UINT64_MAX
+            : start + HAL_SERIAL_TX_TIMEOUT_US;
+        for (uint32_t spin = 0; spin < HAL_SERIAL_TIMER_SPIN_CAP; ++spin) {
+            if ((__inbyte(HAL_COM1_STATUS_PORT) & HAL_COM1_TX_READY) != 0)
+                return true;
+            if (HalTimerQueryTicks() >= deadline)
+                return false;
+            _mm_pause();
+        }
+        return false;
+    }
+
+    // Serial is registered before timer calibration, so keep the early path small and finite.
+    for (uint32_t spin = 0; spin < HAL_SERIAL_EARLY_SPINS; ++spin) {
         if ((__inbyte(HAL_COM1_STATUS_PORT) & HAL_COM1_TX_READY) != 0)
             return true;
         _mm_pause();