wip: IPC and Runtime

Kernel/Source/OS/IPC.c

@@ -0,0 +1,46 @@
+#include <OS/IPC.h>
+#include <OS/Scheduler.h>
+#include <Arch/CPU.h>
+#include <Arch/Exceptions.h>
+
+UInt64 IPCSend(OSTask* sender, UInt64 handleID, UInt64 data) {
+    if (handleID == 0) return -1;
+    OSProcess* currentProcess = sender->process;
+    OSTask* targetTask = (OSTask*)SchedulerProcessGetHandle(currentProcess, handleID, kOSHandleTypeTask);
+    if (!targetTask) return -1;
+
+    if (targetTask->state == OSTaskStateBlockedReceive) {
+        ExceptionsContext* receiverContext = (ExceptionsContext*)targetTask->stackPointer;
+        receiverContext->x1 = data;
+        receiverContext->x0 = currentProcess->id;
+
+        targetTask->state = OSTaskStateRunning;
+        return 0;
+    }
+
+    if (targetTask->senderWaiting != nullptr) return -2;
+
+    targetTask->senderWaiting = sender;
+
+    SchedulerBlockCurrentTask(OSTaskStateBlockedSend);
+    return 0;
+}
+
+void IPCReceive(ExceptionsContext* receiverFrame) {
+    OSTask* receiver = SchedulerGetCurrentTask();
+
+    if (receiver->senderWaiting != nullptr) {
+        OSTask* sender = receiver->senderWaiting;
+
+        ExceptionsContext* senderContext = (ExceptionsContext*)sender->stackPointer;
+
+        receiverFrame->x1 = senderContext->x1;       // Data
+        receiverFrame->x0 = sender->process->id;     // Sender ID
+
+        receiver->senderWaiting = nullptr;
+        sender->state = OSTaskStateRunning;
+        return;
+    }
+
+    SchedulerBlockCurrentTask(OSTaskStateBlockedReceive);
+}

Kernel/Source/OS/Modules.c

@@ -7,7 +7,7 @@
 #include <Arch/CPU.h>
 #include "../Common/bootinfo.h"
 
-void ModuleLoad(BootModule* module) {
+OSTask* ModuleLoad(BootModule* module) {
     OSProcess* userProc = HeapAllocate(sizeof(OSProcess));
     MemorySet(userProc, 0, sizeof(OSProcess));
     userProc->id = SchedulerGetNextProcessID();
@@ -56,8 +56,8 @@ void ModuleLoad(BootModule* module) {
 
     if ((Address)userEntryPoint == 0x0) {
         OSLog("Skipping module %s: entry point is 0x0.\n", module->name);
-        return;
+        return nullptr;
     }
 
-    SchedulerSpawn(userEntryPoint, userProc, true, userStackVirt + kVMPageSize);
+    return SchedulerSpawn(userEntryPoint, userProc, true, userStackVirt + kVMPageSize);
 }

Kernel/Source/OS/Scheduler.c

@@ -69,6 +69,7 @@ OSTask* SchedulerSpawn(void(*entryPoint)(), OSProcess* owner, Boolean isUser, Ad
     task->waitingForProcessId = -1;
 
     task->next = gOSSchedulerCurrentTask->next;
+    task->senderWaiting = nullptr;
     gOSSchedulerCurrentTask->next = task;
 
     return task;
@@ -126,3 +127,30 @@ void SchedulerYield(UInt64 ticks) {
 UInt64 SchedulerGetNextProcessID() {
     return gOSSchedulerNextProcessID++;
 }
+
+void SchedulerBlockCurrentTask(UInt32 newState) {
+    gOSSchedulerCurrentTask->state = newState;
+    CPUException(kOSSchedulerExceptionNumber);
+}
+
+OSTask* SchedulerGetCurrentTask() {
+    return gOSSchedulerCurrentTask;
+}
+
+Int32 SchedulerProcessAllocateHandle(OSProcess* process, OSHandleType type, Pointer object) {
+    for (Int32 i = 1; i < kOSMaxHandlesPerProcess; i++) {
+        if (process->handles[i].type == kOSHandleTypeNone) {
+            process->handles[i].type = type;
+            process->handles[i].object = object;
+            return i;
+        }
+    }
+    return -1;
+}
+
+Pointer SchedulerProcessGetHandle(OSProcess* process, UInt32 handleId, OSHandleType expectedType) {
+    if (handleId == 0 || handleId >= kOSMaxHandlesPerProcess) return nullptr;
+    OSHandle* handle = &process->handles[handleId];
+    if (handle->type != expectedType) return nullptr;
+    return handle->object;
+}

Kernel/Source/OS/Syscall.c

@@ -0,0 +1,25 @@
+#include <OS/Syscall.h>
+#include <OS/IPC.h>
+#include <OS/Scheduler.h>
+#include <OS/Panic.h>
+#include <Arch/Exceptions.h>
+
+Address SyscallDispatch(ExceptionsContext* frame) {
+    UInt64 syscallNumber = frame->x8;
+    OSTask* current = SchedulerGetCurrentTask();
+
+    switch (syscallNumber) {
+        case kSyscallSend:
+            frame->x0 = IPCSend(current, frame->x0, frame->x1);
+            break;
+        case kSyscallReceive:
+            IPCReceive(frame);
+            break;
+        default:
+            frame->x0 = -1;
+            break;
+    }
+
+    if (current->state != OSTaskStateRunning) return SchedulerNext((Address)frame);
+    return (Address)frame;
+}