From fcc7ce49d9c2378fe5e83a77822adad5c1289d1b Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Sat, 6 Nov 2021 20:05:32 -0700
Subject: [PATCH] sm/tipc: ensure technical-correctness of sins (no page cost)

---
 .../tipc/tipc_deferral_manager.hpp            | 28 ++++++++++++-------
 stratosphere/sm/source/sm_user_service.hpp    |  2 +-
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/libraries/libstratosphere/include/stratosphere/tipc/tipc_deferral_manager.hpp b/libraries/libstratosphere/include/stratosphere/tipc/tipc_deferral_manager.hpp
index dc70f8a72..573497068 100644
--- a/libraries/libstratosphere/include/stratosphere/tipc/tipc_deferral_manager.hpp
+++ b/libraries/libstratosphere/include/stratosphere/tipc/tipc_deferral_manager.hpp
@@ -96,14 +96,14 @@ namespace ams::tipc {
     };
     static_assert(std::is_standard_layout<DeferrableBaseImpl>::value);
 
-    template<typename Interface>
-    class DeferrableBase : public DeferrableBaseImpl {
+    template<size_t _MessageBufferRequiredSize>
+    class DeferrableBaseImplWithBuffer : public DeferrableBaseImpl {
         private:
-            static constexpr size_t MessageBufferRequiredSize = Interface::MaximumRequestSize;
+            static constexpr size_t MessageBufferRequiredSize = _MessageBufferRequiredSize;
         private:
             u8 m_message_buffer[MessageBufferRequiredSize];
         public:
-            DeferrableBase();
+            DeferrableBaseImplWithBuffer();
         private:
             static consteval size_t GetMessageBufferOffset();
     };
@@ -112,17 +112,25 @@ namespace ams::tipc {
         return AMS_OFFSETOF(DeferrableBaseImpl, m_message_buffer_base);
     }
 
-    template<typename Interface>
-    consteval size_t DeferrableBase<Interface>::GetMessageBufferOffset() {
-        return AMS_OFFSETOF(DeferrableBase<Interface>, m_message_buffer);
+    template<size_t _MessageBufferRequiredSize>
+    consteval size_t DeferrableBaseImplWithBuffer<_MessageBufferRequiredSize>::GetMessageBufferOffset() {
+        return AMS_OFFSETOF(DeferrableBaseImplWithBuffer<_MessageBufferRequiredSize>, m_message_buffer);
     }
 
-    template<typename Interface>
-    ALWAYS_INLINE DeferrableBase<Interface>::DeferrableBase() : DeferrableBaseImpl(MessageBufferRequiredSize) {
+    template<size_t _MessageBufferRequiredSize>
+    ALWAYS_INLINE DeferrableBaseImplWithBuffer<_MessageBufferRequiredSize>::DeferrableBaseImplWithBuffer() : DeferrableBaseImpl(MessageBufferRequiredSize) {
         static_assert(GetMessageBufferOffsetBase() == GetMessageBufferOffset());
-        static_assert(sizeof(DeferrableBase<Interface>) >= sizeof(DeferrableBaseImpl) + MessageBufferRequiredSize);
+        static_assert(sizeof(DeferrableBaseImplWithBuffer<_MessageBufferRequiredSize>) >= sizeof(DeferrableBaseImpl) + MessageBufferRequiredSize);
     }
 
+    template<typename Interface, size_t MaximumDefaultRequestSize = 0>
+    class DeferrableBase : public DeferrableBaseImplWithBuffer<std::max(Interface::MaximumRequestSize, MaximumDefaultRequestSize)> {
+        private:
+            using BaseImpl = DeferrableBaseImplWithBuffer<std::max(Interface::MaximumRequestSize, MaximumDefaultRequestSize)>;
+        public:
+            using BaseImpl::BaseImpl;
+    };
+
     template<class T>
     concept IsDeferrable = std::derived_from<T, impl::DeferrableBaseTag>;
 
diff --git a/stratosphere/sm/source/sm_user_service.hpp b/stratosphere/sm/source/sm_user_service.hpp
index 5d615b5b5..df457c71b 100644
--- a/stratosphere/sm/source/sm_user_service.hpp
+++ b/stratosphere/sm/source/sm_user_service.hpp
@@ -20,7 +20,7 @@
 namespace ams::sm {
 
     /* Service definition. */
-    class UserService : public tipc::DeferrableBase<sm::impl::IUserInterface> {
+    class UserService : public tipc::DeferrableBase<sm::impl::IUserInterface, /* Maximum deferrable CMIF message size: */ 0x20 + util::AlignUp(sizeof(sm::ServiceName), sizeof(u32))> {
         private:
             os::ProcessId m_process_id;
             bool m_initialized;