fix: updated patch.cpp & dev container (#72)

zsrtp · Sep 27, 2022 · 5bdbc88 · 5bdbc88
1 parent 7cb19e3
commit 5bdbc88
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Showing 3 changed files with 72 additions and 21 deletions.
diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
@@ -33,10 +33,10 @@ WORKDIR /etc
 RUN sudo ln -sf /proc/self/mounts mtab
 RUN sudo dkp-pacman -S --noconfirm gamecube-dev wii-dev
 
-# Install the patchers
-WORKDIR /workspaces/romhack/wii
-RUN curl -L https://github.com/zsrtp/romhack-compiler/releases/download/v0.1.1-r2/romhack-v0.1.1-r2-linux-x64-musl.zip | bsdtar -xvf -
-RUN chmod +x romhack
-WORKDIR /workspaces/romhack/gc
-RUN curl -L https://github.com/zsrtp/romhack-compiler/releases/download/v0.1.1-r2/romhack-v0.1.1-r2-linux-x64-musl-gc.zip | bsdtar -xvf -
-RUN chmod +x romhack
+# # Install the patchers
+# WORKDIR /workspaces/romhack/wii
+# RUN curl -L https://github.com/zsrtp/romhack-compiler/releases/download/v0.1.1-r2/romhack-v0.1.1-r2-linux-x64-musl.zip | bsdtar -xvf -
+# RUN chmod +x romhack
+# WORKDIR /workspaces/romhack/gc
+# RUN curl -L https://github.com/zsrtp/romhack-compiler/releases/download/v0.1.1-r2/romhack-v0.1.1-r2-linux-x64-musl-gc.zip | bsdtar -xvf -
+# RUN chmod +x romhack
diff --git a/common/rels/include/patch.h b/common/rels/include/patch.h
@@ -9,6 +9,7 @@ void writeBranch(void* ptr, void* destination);
 void writeBranchLR(void* ptr, void* destination);
 void writeBranchBL(void* ptr, void* destination);
 void writeBranchMain(void* ptr, void* destination, uint32_t branch);
+void writeAbsoluteBranch(void* ptr, void* destination);
 
 /**
  * @brief Hooks a function to execute the provided one instead.
@@ -20,14 +21,22 @@ void writeBranchMain(void* ptr, void* destination, uint32_t branch);
  * @return	A pointer to the allocated trampoline.
  */
 template <typename Func, typename Dest>
-Func hookFunction(Func function, Dest destination) {
+Func hookFunction(Func function, Dest destination, bool absoluteBranch) {
     uint32_t* instructions = reinterpret_cast<uint32_t*>(function);
+    uint32_t instructionCount;
+    uint32_t* trampoline;
 
+    if (absoluteBranch) {
+        instructionCount = 5;
+        trampoline = new (sizeof(uint32_t)) uint32_t[instructionCount];
+    } else {
+        instructionCount = 2;
 #ifdef PLATFORM_WII
-    uint32_t* trampoline = new (0x4, HEAP_ZELDA) uint32_t[2];
+        trampoline = new (sizeof(uint32_t), HEAP_ZELDA) uint32_t[instructionCount];
 #else
-    uint32_t* trampoline = new (0x4) uint32_t[2];
+        trampoline = new (sizeof(uint32_t)) uint32_t[instructionCount];
 #endif
+    }
 
     // Original instruction
     trampoline[0] = instructions[0];
@@ -40,36 +49,65 @@ Func hookFunction(Func function, Dest destination) {
     // Write actual hook
     writeBranch(&instructions[0], reinterpret_cast<void*>(static_cast<Func>(destination)));
 
+    // Branch to original function past hook
+    if (absoluteBranch) {
+        writeAbsoluteBranch(&trampoline[1], &instructions[1]);
+    } else {
+        writeBranch(&trampoline[1], &instructions[1]);
+    }
+
     return reinterpret_cast<Func>(trampoline);
 }
 
+template <typename Func, typename Dest>
+Func hookFunction(Func function, Dest destination) {
+    return hookFunction(function, destination, false);
+}
+
+template <typename Func, typename Dest>
+Func hookFunctionAbsolute(Func function, Dest destination) {
+    return hookFunction(function, destination, true);
+}
+
 template <typename Func>
 Func unhookFunction(Func trampoline) {
     if (!trampoline) {
         return nullptr;
     }
 
     uint32_t* instructions = reinterpret_cast<uint32_t*>(trampoline);
+    uint32_t instructionCount;
+    uint32_t* address;
+
+    uint32_t firstInstruction = instructions[1];
+    if ((firstInstruction >> 16) == 0x3D80) {  // lis r12
+        // Absolute branch
+        instructionCount = 5;
+        uint32_t instructionAddress = (firstInstruction & 0xFFFF) << 16;  // Upper 16 bits
+        instructionAddress |= (instructions[2] & 0xFFFF);                 // Lower 16 bits
+        address = reinterpret_cast<uint32_t*>(instructionAddress - 0x4);
+    } else {
+        // Standard branchinstructionCount = 2;
+        int32_t branchLength = firstInstruction & 0x03FFFFFC;
 
-    // Restore the original instruction
-    int32_t branchLength = instructions[1] & 0x03FFFFFC;
+        // Check if this is a negative branch
+        if (branchLength > 0x01FFFFFC) {
+            const int32_t Width = 26;
+            const int32_t Mask = (1 << (Width - 1));
+            branchLength = (branchLength ^ Mask) - Mask - 0x4;
+        }
 
-    // Check if this is a negative branch
-    if (branchLength > 0x01FFFFFC) {
-        const int32_t Width = 26;
-        const int32_t Mask = (1 << (Width - 1));
-        branchLength = (branchLength ^ Mask) - Mask - 0x4;
+        uint32_t instructionAddress = reinterpret_cast<uint32_t>(&instructions[1]);
+        address = reinterpret_cast<uint32_t*>(instructionAddress + branchLength);
     }
 
-    uint32_t instructionAddress = reinterpret_cast<uint32_t>(&instructions[1]);
-    uint32_t* address = reinterpret_cast<uint32_t*>(instructionAddress + branchLength);
     *address = instructions[0];
 
     // Clear the cache for both the address and where the instructions were stored
     DCFlushRange(address, sizeof(uint32_t));
     ICInvalidateRange(address, sizeof(uint32_t));
-    DCFlushRange(instructions, sizeof(uint32_t));
-    ICInvalidateRange(instructions, sizeof(uint32_t));
+    DCFlushRange(instructions, sizeof(uint32_t) * instructionCount);
+    ICInvalidateRange(instructions, sizeof(uint32_t) * instructionCount);
 
     // Free the memory used by the trampoline
     delete[] instructions;

diff --git a/common/rels/src/patch.cpp b/common/rels/src/patch.cpp
@@ -29,3 +29,16 @@ void writeBranchMain(void* ptr, void* destination, uint32_t branch) {
     DCFlushRange(ptr, sizeof(uint32_t));
     ICInvalidateRange(ptr, sizeof(uint32_t));
 }
+
+void writeAbsoluteBranch(void* ptr, void* destination) {
+    uint32_t dstRaw = reinterpret_cast<uint32_t>(destination);
+    uint32_t* code = reinterpret_cast<uint32_t*>(ptr);
+
+    code[0] = 0x3D800000 | (dstRaw >> 16);     // lis r12,dstRaw@h
+    code[1] = 0x618C0000 | (dstRaw & 0xFFFF);  // ori r12,r12,dstRaw@l
+    code[2] = 0x7D8903A6;                      // mtctr r12
+    code[3] = 0x4E800420;                      // bctr
+
+    DCFlushRange(ptr, sizeof(uint32_t) * 4);
+    ICInvalidateRange(ptr, sizeof(uint32_t) * 4);
+}