From 9f91ba1f7357c61dd2c7c3b437ea203d467fd400 Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Fri, 17 Nov 2023 23:44:53 +0200
Subject: arm: Implement native code execution backend

---
 src/core/arm/nce/patch.h | 107 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 src/core/arm/nce/patch.h

(limited to 'src/core/arm/nce/patch.h')

diff --git a/src/core/arm/nce/patch.h b/src/core/arm/nce/patch.h
new file mode 100644
index 000000000..b727d4e48
--- /dev/null
+++ b/src/core/arm/nce/patch.h
@@ -0,0 +1,107 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <span>
+#include <unordered_map>
+#include <vector>
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wshorten-64-to-32"
+#include <oaknut/code_block.hpp>
+#include <oaknut/oaknut.hpp>
+#pragma clang diagnostic pop
+
+#include "common/common_types.h"
+#include "core/hle/kernel/code_set.h"
+#include "core/hle/kernel/k_typed_address.h"
+#include "core/hle/kernel/physical_memory.h"
+
+#include <signal.h>
+
+namespace Core {
+struct GuestContext;
+}
+
+namespace Core::NCE {
+
+enum class PatchMode : u32 {
+    None,
+    PreText,  ///< Patch section is inserted before .text
+    PostData, ///< Patch section is inserted after .data
+};
+
+using ModuleTextAddress = u64;
+using PatchTextAddress = u64;
+using EntryTrampolines = std::unordered_map<ModuleTextAddress, PatchTextAddress>;
+
+class Patcher {
+public:
+    explicit Patcher();
+    ~Patcher();
+
+    void PatchText(const Kernel::PhysicalMemory& program_image,
+                   const Kernel::CodeSet::Segment& code);
+    void RelocateAndCopy(Common::ProcessAddress load_base, const Kernel::CodeSet::Segment& code,
+                         Kernel::PhysicalMemory& program_image, EntryTrampolines* out_trampolines);
+    size_t SectionSize() const noexcept;
+
+    [[nodiscard]] PatchMode Mode() const noexcept {
+        return mode;
+    }
+
+private:
+    using ModuleDestLabel = uintptr_t;
+
+    struct Trampoline {
+        ptrdiff_t patch_offset;
+        uintptr_t module_offset;
+    };
+
+    void WriteLoadContext();
+    void WriteSaveContext();
+    void LockContext();
+    void UnlockContext();
+    void WriteSvcTrampoline(ModuleDestLabel module_dest, u32 svc_id);
+    void WriteMrsHandler(ModuleDestLabel module_dest, oaknut::XReg dest_reg,
+                         oaknut::SystemReg src_reg);
+    void WriteMsrHandler(ModuleDestLabel module_dest, oaknut::XReg src_reg);
+    void WriteCntpctHandler(ModuleDestLabel module_dest, oaknut::XReg dest_reg);
+
+private:
+    void BranchToPatch(uintptr_t module_dest) {
+        m_branch_to_patch_relocations.push_back({c.offset(), module_dest});
+    }
+
+    void BranchToModule(uintptr_t module_dest) {
+        m_branch_to_module_relocations.push_back({c.offset(), module_dest});
+        c.dw(0);
+    }
+
+    void WriteModulePc(uintptr_t module_dest) {
+        m_write_module_pc_relocations.push_back({c.offset(), module_dest});
+        c.dx(0);
+    }
+
+private:
+    // List of patch instructions we have generated.
+    std::vector<u32> m_patch_instructions{};
+
+    // Relocation type for relative branch from module to patch.
+    struct Relocation {
+        ptrdiff_t patch_offset;  ///< Offset in bytes from the start of the patch section.
+        uintptr_t module_offset; ///< Offset in bytes from the start of the text section.
+    };
+
+    oaknut::VectorCodeGenerator c;
+    std::vector<Trampoline> m_trampolines;
+    std::vector<Relocation> m_branch_to_patch_relocations{};
+    std::vector<Relocation> m_branch_to_module_relocations{};
+    std::vector<Relocation> m_write_module_pc_relocations{};
+    oaknut::Label m_save_context{};
+    oaknut::Label m_load_context{};
+    PatchMode mode{PatchMode::None};
+};
+
+} // namespace Core::NCE
-- 
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