NRO loading bringup

crt0/switch_crt0.s

@@ -8,13 +8,16 @@ _start:
 
 .org _start+0x80
 startup:
+    // save lr
+    mov  x27, x30
+
     // get aslr base
     bl   +4
-    sub  x28, x30, #0x84
+    sub  x28, x30, #0x88
 
-    // save context ptr and main thread handle
+    // context ptr and main thread handle
-    mov  x26, x0
+    mov  x25, x0
-    mov  x27, x1
+    mov  x26, x1
 
     // clear .bss
     adrp x0, __bss_start__
@@ -37,8 +40,9 @@ bss_loop:
     bl   __nx_dynamic
 
     // initialize system
-    mov  x0, x26
+    mov  x0, x25
-    mov  x1, x27
+    mov  x1, x26
+    mov  x2, x27
     bl   __libnx_init
 
     // call entrypoint

nx/include/switch/runtime/env.h

@@ -1,6 +1,33 @@
 // Copyright 2018 plutoo
 
-void envParse(void* ctx, Handle main_thread);
+typedef struct {
+    u32 Key;
+    u32 Flags;
+    u64 Value[2];
+} ConfigEntry;
+
+enum {
+    EntryFlag_IsMandatory = BIT(0),
+};
+
+enum {
+    EntryType_EndOfList=0,
+    EntryType_MainThreadHandle=1,
+    EntryType_NextLoadPath=2,
+    EntryType_OverrideHeap=3,
+    EntryType_OverrideService=4,
+    EntryType_Argv=5,
+    EntryType_SyscallAvailableHint=6,
+    EntryType_AppletType=7,
+    EntryType_AppletWorkaround=8,
+    EntryType_StdioSockets=9,
+    EntryType_ProcessHandle=10,
+    EntryType_LastLoadResult=11
+};
+
+typedef void NORETURN (*LoaderReturnFn)(int result_code);
+
+void envParse(void* ctx, Handle main_thread, LoaderReturnFn saved_lr);
 
 Handle envGetMainThreadHandle(void);
 bool envIsNso(void);
@@ -15,4 +42,4 @@ void* envGetArgv(void);
 
 bool envIsSyscallHinted(u8 svc);
 
-typedef void __attribute__((noreturn)) (*LoaderReturnFn)(int result_code);
+LoaderReturnFn envGetExitFuncPtr(void);

nx/source/kernel/thread.c

@@ -47,7 +47,6 @@ Result threadCreate(
         rc = MAKERESULT(MODULE_LIBNX, LIBNX_OUTOFMEM);
     }
     else {
-        // todo: svcMapMemory returns 0xDC01
         void* stack_mirror = virtmemReserveMap(stack_sz);
         rc = svcMapMemory(stack_mirror, stack, stack_sz);
 

nx/source/runtime/env.c

@@ -8,42 +8,35 @@ static void*  g_overrideHeapAddr = NULL;
 static u64    g_overrideHeapSize = 0;
 static u64    g_overrideArgc = 0;
 static void*  g_overrideArgv = NULL;
-static u64    g_syscallHints[0x80/8];
+static u64    g_syscallHints[2];
+static Handle g_processHandle = INVALID_HANDLE;
 
-typedef struct {
+extern __attribute__((weak)) u32 __nx_applet_type;
-    u32 Key;
-    u32 Flags;
-    u64 Value[2];
-} ConfigEntry;
 
-enum {
+void envParse(void* ctx, Handle main_thread, LoaderReturnFn saved_lr)
-    IsMandatory = BIT(0),
-};
-
-enum {
-    EntryType_EndOfList=0,
-    EntryType_MainThreadHandle=1,
-    EntryType_LoaderReturnAddr=2,
-    EntryType_OverrideHeap=3,
-    EntryType_OverrideService=4,
-    EntryType_Argv=5,
-    EntryType_SyscallAvailableHint=6,
-    EntryType_AppletType=7
-};
-
-void envParse(void* ctx, Handle main_thread)
 {
+    // If we're running under NSO, we should just call svcExitProcess.
+    // Otherwise we should return to loader via LR.
+    if (saved_lr == NULL) {
+        g_loaderRetAddr = (LoaderReturnFn) &svcExitProcess;
+    }
+    else {
+        g_loaderRetAddr = saved_lr;
+    }
+
+    // Detect NSO environment.
     if (main_thread != INVALID_HANDLE)
     {
         g_mainThreadHandle = main_thread;
         g_isNso = true;
 
         // For NSO we assume kernelhax thus access to all syscalls.
-        memset((void*) &g_syscallHints, 0xFF, sizeof(g_syscallHints));
+        g_syscallHints[0] = g_syscallHints[1] = -1ull;
 
         return;
     }
 
+    // Parse NRO config entries.
     ConfigEntry* ent = ctx;
 
     while (ent->Key != EntryType_EndOfList)
@@ -54,8 +47,8 @@ void envParse(void* ctx, Handle main_thread)
             g_mainThreadHandle = ent->Value[0];
             break;
 
-        case EntryType_LoaderReturnAddr:
+        case EntryType_NextLoadPath:
-            g_loaderRetAddr = (void*) ent->Value[0];
+            // TODO
             break;
 
         case EntryType_OverrideHeap:
@@ -72,26 +65,21 @@ void envParse(void* ctx, Handle main_thread)
             g_overrideArgv = (void*) ent->Value[1];
             break;
 
-        case EntryType_SyscallAvailableHint: {
+        case EntryType_SyscallAvailableHint:
-            int i, j;
+            g_syscallHints[0] = ent->Value[0];
-
+            g_syscallHints[1] = ent->Value[1];
-            for (i=0; i<2; i++) for (j=0; j<8; j++)
-            {
-                u8 svc = ent->Value[i] >> (8*j);
-
-                if (svc < 0x80)
-                    g_syscallHints[svc/64] |= 1llu << (svc%64);
-            }
-
             break;
-        }
 
         case EntryType_AppletType:
-            // TODO
+            __nx_applet_type = ent->Value[0];
+            break;
+
+        case EntryType_ProcessHandle:
+            g_processHandle = ent->Value[0];
             break;
 
         default:
-            if (ent->Flags & IsMandatory)
+            if (ent->Flags & EntryFlag_IsMandatory)
             {
                 // Encountered unknown but mandatory key, bail back to loader.
                 g_loaderRetAddr(MAKERESULT(346, 100 + ent->Key));
@@ -142,5 +130,13 @@ void* envGetArgv(void) {
 }
 
 bool envIsSyscallHinted(u8 svc) {
-    return !!(g_syscallHints[svc/64] & (1llu << (svc%64)));
+    return !!(g_syscallHints[svc/64] & (1ull << (svc%64)));
+}
+
+Handle envGetOwnProcessHandle(void) {
+    return g_processHandle;
+}
+
+LoaderReturnFn envGetExitFuncPtr(void) {
+    return g_loaderRetAddr;
 }

nx/source/runtime/init.c

@@ -97,12 +97,12 @@ void __attribute__((weak)) __appExit(void)
     smExit();
 }
 
-void __attribute__((weak)) __libnx_init(void* ctx, Handle main_thread)
+void __attribute__((weak)) __libnx_init(void* ctx, Handle main_thread, void* saved_lr)
 {
     // Called by crt0.
 
     // Libnx initialization goes here.
-    envParse(ctx, main_thread);
+    envParse(ctx, main_thread, saved_lr);
     newlibSetup();
     virtmemSetup();
     __libnx_initheap();
@@ -127,6 +127,6 @@ void __attribute__((weak)) NORETURN __libnx_exit(int rc)
     // Clean up services.
     __appExit();
 
-    svcExitProcess();
+    envGetExitFuncPtr()(0);
     while(1);
 }