Restore initial sp on application exit

nx/source/runtime/env.c

@@ -4,6 +4,8 @@
 #include "services/sm.h"
 #include "services/fatal.h"
 
+void NORETURN __nx_exit(LoaderReturnFn retaddr, Result rc);
+
 static bool   g_isNso = false;
 static Handle g_mainThreadHandle = INVALID_HANDLE;
 static LoaderReturnFn g_loaderRetAddr = NULL;
@@ -88,7 +90,7 @@ void envSetup(void* ctx, Handle main_thread, LoaderReturnFn saved_lr)
             if (ent->Flags & EntryFlag_IsMandatory)
             {
                 // Encountered unknown but mandatory key, bail back to loader.
-                g_loaderRetAddr(MAKERESULT(346, 100 + ent->Key));
+                __nx_exit(g_loaderRetAddr, MAKERESULT(346, 100 + ent->Key));
             }
 
             break;

nx/source/runtime/init.c

@@ -7,7 +7,8 @@
 #include "services/applet.h"
 #include "runtime/devices/fs_dev.h"
 
-void __nx_exit(int rc);
+void* __stack_top;
+void NORETURN __nx_exit(LoaderReturnFn retaddr, Result rc);
 
 void virtmemSetup(void);
 void newlibSetup(void);
@@ -133,6 +134,5 @@ void __attribute__((weak)) NORETURN __libnx_exit(int rc)
     // Clean up services.
     __appExit();
 
-    envGetExitFuncPtr()(0);
-    while(1);
+    __nx_exit(envGetExitFuncPtr(), 0);
 }

nx/source/runtime/switch_crt0.s

@@ -33,6 +33,11 @@ bss_loop:
     subs x1, x1, #8
     bne  bss_loop
 
+    // store stack pointer
+    mov  x1, sp
+    adrp x0, __stack_top
+    str  x1, [x0, #:lo12:__stack_top]
+
     // process .dynamic section
     mov  x0, x28
     adrp x1, _DYNAMIC
@@ -53,3 +58,17 @@ bss_loop:
     adrp x30, __libnx_exit
     add  x30, x30, #:lo12:__libnx_exit
     b    main
+
+.global __nx_exit
+.type   __nx_exit, %function
+__nx_exit:
+    mov  x8, x0
+
+    // restore stack pointer
+    adrp x0, __stack_top
+    ldr  x0, [x0, #:lo12:__stack_top]
+    mov  sp, x0
+
+    // jump back to loader
+    mov  x0, #0
+    br   x8