implement proper IRQL, DPCs, kernel and user APCs, alertable waits, async file I/O with cancellation, trap frames, selftests, a real driver/device model, native async FAT32, VFAT dotfile fixes, syscall ABI cleanup, async_apc and async_cancel tests, POSIX multi-volume paths, and pimp the readme.

code/kernel/ke_dpc.h

@@ -0,0 +1,44 @@
+#pragma once
+// ke_dpc.h - deferred procedure calls
+//
+// DPCs are the kernel's bottom-half mechanism.  Hardware ISRs can queue a DPC
+// after acknowledging/capturing device state; the DPC then runs later at
+// DISPATCH_LEVEL from the common interrupt-exit path.  DPC routines must not
+// wait, block, or call PASSIVE_LEVEL-only code.
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <ke_list.h>
+#include <ke_spinlock.h>
+
+typedef struct KDPC KDPC;
+
+typedef void (*KDEFERRED_ROUTINE)(KDPC* dpc,
+                                  void* context,
+                                  void* systemArgument1,
+                                  void* systemArgument2);
+
+struct KDPC {
+    LIST_ENTRY        Link;
+    KDEFERRED_ROUTINE Routine;
+    void*             Context;
+    void*             SystemArgument1;
+    void*             SystemArgument2;
+    volatile long     Inserted;
+};
+
+// Called during kernel bring-up before interrupts are enabled.
+void KeInitializeDpcSystem(void);
+
+__declspec(dllexport) void KeInitializeDpc(KDPC* dpc,
+                                           KDEFERRED_ROUTINE routine,
+                                           void* context);
+
+// Queue a DPC if it is not already queued.  Returns false if the DPC was
+// already pending or the arguments are invalid.
+__declspec(dllexport) bool KeInsertQueueDpc(KDPC* dpc,
+                                            void* systemArgument1,
+                                            void* systemArgument2);
+
+// Internal: drain queued DPCs at DISPATCH_LEVEL.  Called from interrupt exit.
+void KiDrainDpcQueue(void);