From 9fa1d42aa86b3a247fc8d94ee438f2a680f37cd3 Mon Sep 17 00:00:00 2001
From: TuxSH <1922548+TuxSH@users.noreply.github.com>
Date: Sun, 9 Jul 2023 22:00:51 +0200
Subject: [PATCH] Loader: make it simpler to load ext. modules by clearing N3DS
 bit

And also move the location of IPS/BPS patches for (non-KIP) sysmodules
to /luma/sysmodules/<titleId>.<ips/bps> and only require "Load ext
firm/modules" option for it.
---
 sysmodules/loader/source/bps_patcher.cpp | 22 ++++++++++++---
 sysmodules/loader/source/loader.c        |  7 +++--
 sysmodules/loader/source/patcher.c       | 36 +++++++++++++++++-------
 3 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/sysmodules/loader/source/bps_patcher.cpp b/sysmodules/loader/source/bps_patcher.cpp
index 0c8ca0a..7092c3c 100644
--- a/sysmodules/loader/source/bps_patcher.cpp
+++ b/sysmodules/loader/source/bps_patcher.cpp
@@ -247,11 +247,25 @@ private:
 
 static inline bool ApplyCodeBpsPatch(u64 prog_id, u8 *code, u32 size)
 {
-    char bps_path[] = "/luma/titles/0000000000000000/code.bps";
-    progIdToStr(bps_path + 28, prog_id);
+    bool isSysmodule = (prog_id >> 32) == 0x00040130;
     util::File patch_file;
-    if(!patch_file.Open(bps_path, FS_OPEN_READ))
-        return true;
+
+    if (isSysmodule)
+    {
+        char bps_path[] = "/luma/sysmodules/0000000000000000.bps";
+        prog_id &= ~0xF0000000ull; // clear N3DS bit
+        progIdToStr(bps_path + 32, prog_id);
+        if(!patch_file.Open(bps_path, FS_OPEN_READ))
+            return true;
+    }
+    else
+    {
+        char bps_path[] = "/luma/titles/0000000000000000/code.bps";
+        progIdToStr(bps_path + 28, prog_id);
+        if(!patch_file.Open(bps_path, FS_OPEN_READ))
+            return true;
+    }
+
     const u32 patch_size = u32(patch_file.GetSize().value_or(0));
 
     // Temporarily use APPLICATION memory to store the source and patch data.
diff --git a/sysmodules/loader/source/loader.c b/sysmodules/loader/source/loader.c
index ab94287..721db7b 100644
--- a/sysmodules/loader/source/loader.c
+++ b/sysmodules/loader/source/loader.c
@@ -394,15 +394,16 @@ static Result RegisterProgram(u64 *programHandle, FS_ProgramInfo *title, FS_Prog
         bool loadedCxiFromStorage = false;
         if (IsSysmoduleId(titleId) && CONFIG(LOADEXTFIRMSANDMODULES))
         {
+            u64 tid2 = titleId & ~0xF0000000ull;
             // Forbid having two such file handles being open at the same time
             // Also reload the file even if already cached.
             InvalidateCachedCxiFile();
 
-            res = openSysmoduleCxi(&g_cached_sysmoduleCxiFile, titleId);
+            res = openSysmoduleCxi(&g_cached_sysmoduleCxiFile, tid2);
             if (R_SUCCEEDED(res))
             {
-                // A .cxi with the correct name in /luma/sysmodule exists, proceed
-                *programHandle = SYSMODULE_CXI_COOKIE_MASK | (u32)titleId;
+                // A .cxi with the correct name in /luma/sysmodule exists, proceed (ignoring N3DS TID bits)
+                *programHandle = SYSMODULE_CXI_COOKIE_MASK | (u32)tid2;
                 g_cached_sysmoduleCxiCookie = *programHandle;
                 loadedCxiFromStorage = true;
             }
diff --git a/sysmodules/loader/source/patcher.c b/sysmodules/loader/source/patcher.c
index a7d0301..e427abd 100644
--- a/sysmodules/loader/source/patcher.c
+++ b/sysmodules/loader/source/patcher.c
@@ -265,12 +265,22 @@ static inline bool applyCodeIpsPatch(u64 progId, u8 *code, u32 size)
     /* Here we look for "/luma/titles/[u64 titleID in hex, uppercase]/code.ips"
        If it exists it should be an IPS format patch */
 
-    char path[] = "/luma/titles/0000000000000000/code.ips";
-    progIdToStr(path + 28, progId);
-
+    bool isSysmodule = (progId >> 32) == 0x00040130;
     IFile file;
 
-    if(!openLumaFile(&file, path)) return true;
+    if (isSysmodule)
+    {
+        char path[] = "/luma/sysmodules/0000000000000000.ips";
+        progId &= ~0xF0000000ull; // clear N3DS bit
+        progIdToStr(path + 32, progId);
+        if(!openLumaFile(&file, path)) return true;
+    }
+    else
+    {
+        char path[] = "/luma/titles/0000000000000000/code.ips";
+        progIdToStr(path + 28, progId);
+        if(!openLumaFile(&file, path)) return true;
+    }
 
     bool ret = false;
     u8 buffer[5];
@@ -321,6 +331,7 @@ exit:
 
 Result openSysmoduleCxi(IFile *outFile, u64 progId)
 {
+    progId &= ~0xF0000000ull; // clear N3DS bit
     char path[] = "/luma/sysmodules/0000000000000000.cxi";
     progIdToStr(path + sizeof("/luma/sysmodules/0000000000000000") - 2, progId);
 
@@ -619,6 +630,10 @@ void patchCode(u64 progId, u16 progVer, u8 *code, u32 size, u32 textSize, u32 ro
                       progId == 0x000400300000A102LL || //CHN Home Menu
                       progId == 0x000400300000B102LL;   //TWN Home Menu
 
+    bool isApp = ((progId >> 32) & ~0x12) == 0x00040000;
+    bool isApplet = (progId >> 32) == 0x00040030;
+    bool isSysmodule = (progId >> 32) == 0x00040130;
+
     if(isHomeMenu)
     {
         bool applyRegionFreePatch = true;
@@ -909,14 +924,15 @@ void patchCode(u64 progId, u16 progVer, u8 *code, u32 size, u32 textSize, u32 ro
             )) goto error;
     }
 
+    if (isSysmodule && CONFIG(LOADEXTFIRMSANDMODULES))
+    {
+        if(!patcherApplyCodeBpsPatch(progId, code, size)) goto error;
+        if(!applyCodeIpsPatch(progId, code, size)) goto error;
+    }
+
     if(CONFIG(PATCHGAMES))
     {
-        bool isApp = ((progId >> 32) & ~0x12) == 0x00040000;
-        bool isApplet = (progId >> 32) == 0x00040030;
-        bool isSysmodule = (progId >> 32) == 0x00040130;
-
-        bool shouldPatchIps = !isSysmodule || (isSysmodule && CONFIG(LOADEXTFIRMSANDMODULES));
-        if (shouldPatchIps)
+        if (!isSysmodule)
         {
             if(!patcherApplyCodeBpsPatch(progId, code, size)) goto error;
             if(!applyCodeIpsPatch(progId, code, size)) goto error;