kern: implement user thread start, el0 code now runs

libraries/libmesosphere/include/mesosphere/arch/arm64/kern_k_page_table_entry.hpp

@@ -145,7 +145,7 @@ namespace ams::kern::arch::arm64 {
             constexpr ALWAYS_INLINE decltype(auto) SetAccessFlag(AccessFlag f)        { this->SetBitsDirect(10, 1, f); return *this; }
             constexpr ALWAYS_INLINE decltype(auto) SetShareable(Shareable s)          { this->SetBitsDirect(8, 2, s); return *this; }
             constexpr ALWAYS_INLINE decltype(auto) SetReadOnly(bool en)               { this->SetBit(7, en); return *this; }
-            constexpr ALWAYS_INLINE decltype(auto) SetUserAccessible(bool en)         { this->SetBit(7, en); return *this; }
+            constexpr ALWAYS_INLINE decltype(auto) SetUserAccessible(bool en)         { this->SetBit(6, en); return *this; }
             constexpr ALWAYS_INLINE decltype(auto) SetPageAttribute(PageAttribute a)  { this->SetBitsDirect(2, 3, a); return *this; }
 
             constexpr ALWAYS_INLINE u64 GetEntryTemplate() const {

libraries/libmesosphere/include/mesosphere/kern_k_capabilities.hpp

@@ -222,7 +222,6 @@ namespace ams::kern {
             }
 
             bool SetSvcAllowed(u32 id) {
-                constexpr size_t BitsPerWord = BITSIZEOF(this->svc_access_flags[0]);
                 if (id < BITSIZEOF(this->svc_access_flags)) {
                     SetSvcAllowedImpl(this->svc_access_flags, id);
                     return true;

libraries/libmesosphere/source/arch/arm64/kern_k_thread_context.cpp

@@ -22,7 +22,20 @@ namespace ams::kern::arch::arm64 {
     void SupervisorModeThreadStarter();
 
     void OnThreadStart() {
-        MESOSPHERE_TODO_IMPLEMENT();
+        MESOSPHERE_ASSERT(!KInterruptManager::AreInterruptsEnabled());
+        /* Send KDebug event for this thread's creation. */
+        {
+            KScopedInterruptEnable ei;
+            /* TODO */
+        }
+
+        /* Handle any pending dpc. */
+        while (GetCurrentThread().HasDpc()) {
+            KDpcManager::HandleDpc();
+        }
+
+        /* Clear our status as in an exception handler */
+        GetCurrentThread().ClearInExceptionHandler();
     }
 
     namespace {

mesosphere/kernel/source/arch/arm64/kern_k_thread_context_asm.s

@@ -39,7 +39,7 @@ _ZN3ams4kern4arch5arm6421UserModeThreadStarterEv:
     msr sp_el0,    x19
     msr elr_el1,   x20
     msr spsr_el1,  x21
-    msr tpidr_el1, x22
+    msr tpidr_el0, x22
 
     ldp x0,  x1,  [sp, #(8 *  0)]
     ldp x2,  x3,  [sp, #(8 *  2)]