feat(ipc): implement synchronous Rendezvous IPC and multi-thread cooperative scheduler

lib/libipc_cpp/include/ipc.hpp

@@ -24,6 +24,13 @@ struct FastResponse {
     uint64_t out1;
 };
 
+struct IncomingRequest {
+    uint64_t sender_tid;
+    uint64_t opcode;
+    uint64_t arg0;
+    uint64_t arg1;
+};
+
 // RAII Capability Handle
 class Capability {
 private:
@@ -56,7 +63,7 @@ public:
     [[nodiscard]] constexpr bool is_valid() const noexcept { return handle_ != CAP_NULL; }
 };
 
-// RAII IPC Endpoint Wrapper
+// RAII IPC Client Endpoint Wrapper
 class Endpoint {
 private:
     Capability cap_;
@@ -82,6 +89,36 @@ public:
     [[nodiscard]] cap_t raw_handle() const noexcept { return cap_.get(); }
 };
 
+// RAII IPC Server Endpoint Wrapper
+class ServerEndpoint {
+private:
+    Capability cap_;
+
+public:
+    explicit ServerEndpoint(Capability&& cap) noexcept : cap_(static_cast<Capability&&>(cap)) {}
+    explicit ServerEndpoint(cap_t cap) noexcept : cap_(cap) {}
+
+    // Server main loop: Reply to previous sender and wait for next request
+    [[nodiscard]] Result<IncomingRequest> reply_and_recv(
+        uint64_t reply_to_tid = 0,
+        uint64_t reply_val0 = 0,
+        uint64_t reply_val1 = 0
+    ) const noexcept {
+        uint64_t sender_tid = 0;
+        uint64_t opcode = 0;
+        uint64_t arg0 = 0;
+        uint64_t arg1 = 0;
+        sysret_t ret = sys_ipc_reply_recv_raw(cap_.get(), reply_to_tid, reply_val0, reply_val1,
+                                              &sender_tid, &opcode, &arg0, &arg1);
+        return Result<IncomingRequest>{
+            .status = ret,
+            .value = { sender_tid, opcode, arg0, arg1 }
+        };
+    }
+
+    [[nodiscard]] cap_t raw_handle() const noexcept { return cap_.get(); }
+};
+
 // RAII Shared Memory Buffer
 class SharedBuffer {
 private: