exo2: implement SmcComputeAes, SmcGetResult, SmcGetResultData

exosphere2/program/source/smc/secmon_smc_result.cpp

@@ -16,17 +16,91 @@
 #include <exosphere.hpp>
 #include "../secmon_error.hpp"
 #include "secmon_smc_result.hpp"
+#include "secmon_user_page_mapper.hpp"
 
 namespace ams::secmon::smc {
 
+    namespace {
+
+        constinit u64              g_async_key     = InvalidAsyncKey;
+        constinit GetResultHandler g_async_handler = nullptr;
+
+        u64 GenerateRandomU64() {
+            /* NOTE: This is one of the only places where Nintendo does not do data flushing. */
+            /*       to ensure coherency when doing random byte generation. */
+            /*       It is not clear why it is necessary elsewhere but not here. */
+            /* TODO: Figure out why. */
+            u64 v;
+            se::GenerateRandomBytes(std::addressof(v), sizeof(v));
+            return v;
+        }
+
+    }
+
+    u64 BeginAsyncOperation(GetResultHandler handler) {
+        /* Only allow one async operation at a time. */
+        if (g_async_key != InvalidAsyncKey) {
+            return InvalidAsyncKey;
+        }
+
+        /* Generate a random async key. */
+        g_async_key     = GenerateRandomU64();
+        g_async_handler = handler;
+
+        return g_async_key;
+    }
+
+    void CancelAsyncOperation(u64 async_key) {
+        if (async_key == g_async_key) {
+            g_async_key = InvalidAsyncKey;
+        }
+    }
+
+    void EndAsyncOperation() {
+        gic::SetPending(SecurityEngineUserInterruptId);
+    }
+
     SmcResult SmcGetResult(SmcArguments &args) {
-        /* TODO */
-        return SmcResult::NotImplemented;
+        /* Decode arguments. */
+        const u64 async_key = args.r[1];
+
+        /* Validate arguments. */
+        SMC_R_UNLESS(g_async_key != InvalidAsyncKey,      NoAsyncOperation);
+        SMC_R_UNLESS(g_async_key == async_key,       InvalidAsyncOperation);
+
+        /* Call the handler. */
+        args.r[1] = static_cast<u64>(g_async_handler(nullptr, 0));
+        g_async_key = InvalidAsyncKey;
+
+        return SmcResult::Success;
     }
 
     SmcResult SmcGetResultData(SmcArguments &args) {
-        /* TODO */
-        return SmcResult::NotImplemented;
+        /* Decode arguments. */
+        const u64 async_key            = args.r[1];
+        const uintptr_t user_phys_addr = args.r[2];
+        const size_t    user_size      = args.r[3];
+
+        /* Allocate a work buffer on the stack. */
+        alignas(8) u8 work_buffer[1_KB];
+
+        /* Validate arguments. */
+        SMC_R_UNLESS(g_async_key != InvalidAsyncKey,        NoAsyncOperation);
+        SMC_R_UNLESS(g_async_key == async_key,         InvalidAsyncOperation);
+        SMC_R_UNLESS(user_size <= sizeof(work_buffer),       InvalidArgument);
+
+        /* Call the handler. */
+        args.r[1] = static_cast<u64>(g_async_handler(work_buffer, user_size));
+        g_async_key = InvalidAsyncKey;
+
+        /* Map the user buffer. */
+        {
+            UserPageMapper mapper(user_phys_addr);
+            SMC_R_UNLESS(mapper.Map(),                                              InvalidArgument);
+            SMC_R_UNLESS(mapper.CopyToUser(user_phys_addr, work_buffer, user_size), InvalidArgument);
+        }
+
+        return SmcResult::Success;
     }
 
 }