From 208ed712f42cfd277405a22663197dc1c5e84cfe Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Mon, 6 Jun 2022 12:56:01 -0400
Subject: core/debugger: memory breakpoint support

---
 src/core/arm/dynarmic/arm_dynarmic_32.cpp | 69 ++++++++++++++++++++++++++-----
 1 file changed, 58 insertions(+), 11 deletions(-)

(limited to 'src/core/arm/dynarmic/arm_dynarmic_32.cpp')

diff --git a/src/core/arm/dynarmic/arm_dynarmic_32.cpp b/src/core/arm/dynarmic/arm_dynarmic_32.cpp
index 7c82d0b96..8c90c8be0 100644
--- a/src/core/arm/dynarmic/arm_dynarmic_32.cpp
+++ b/src/core/arm/dynarmic/arm_dynarmic_32.cpp
@@ -29,45 +29,62 @@ using namespace Common::Literals;
 class DynarmicCallbacks32 : public Dynarmic::A32::UserCallbacks {
 public:
     explicit DynarmicCallbacks32(ARM_Dynarmic_32& parent_)
-        : parent{parent_}, memory(parent.system.Memory()) {}
+        : parent{parent_},
+          memory(parent.system.Memory()), debugger_enabled{parent.system.DebuggerEnabled()} {}
 
     u8 MemoryRead8(u32 vaddr) override {
+        CheckMemoryAccess(vaddr, 1, Kernel::DebugWatchpointType::Read);
         return memory.Read8(vaddr);
     }
     u16 MemoryRead16(u32 vaddr) override {
+        CheckMemoryAccess(vaddr, 2, Kernel::DebugWatchpointType::Read);
         return memory.Read16(vaddr);
     }
     u32 MemoryRead32(u32 vaddr) override {
+        CheckMemoryAccess(vaddr, 4, Kernel::DebugWatchpointType::Read);
         return memory.Read32(vaddr);
     }
     u64 MemoryRead64(u32 vaddr) override {
+        CheckMemoryAccess(vaddr, 8, Kernel::DebugWatchpointType::Read);
         return memory.Read64(vaddr);
     }
 
     void MemoryWrite8(u32 vaddr, u8 value) override {
-        memory.Write8(vaddr, value);
+        if (CheckMemoryAccess(vaddr, 1, Kernel::DebugWatchpointType::Write)) {
+            memory.Write8(vaddr, value);
+        }
     }
     void MemoryWrite16(u32 vaddr, u16 value) override {
-        memory.Write16(vaddr, value);
+        if (CheckMemoryAccess(vaddr, 2, Kernel::DebugWatchpointType::Write)) {
+            memory.Write16(vaddr, value);
+        }
     }
     void MemoryWrite32(u32 vaddr, u32 value) override {
-        memory.Write32(vaddr, value);
+        if (CheckMemoryAccess(vaddr, 4, Kernel::DebugWatchpointType::Write)) {
+            memory.Write32(vaddr, value);
+        }
     }
     void MemoryWrite64(u32 vaddr, u64 value) override {
-        memory.Write64(vaddr, value);
+        if (CheckMemoryAccess(vaddr, 8, Kernel::DebugWatchpointType::Write)) {
+            memory.Write64(vaddr, value);
+        }
     }
 
     bool MemoryWriteExclusive8(u32 vaddr, u8 value, u8 expected) override {
-        return memory.WriteExclusive8(vaddr, value, expected);
+        return CheckMemoryAccess(vaddr, 1, Kernel::DebugWatchpointType::Write) &&
+               memory.WriteExclusive8(vaddr, value, expected);
     }
     bool MemoryWriteExclusive16(u32 vaddr, u16 value, u16 expected) override {
-        return memory.WriteExclusive16(vaddr, value, expected);
+        return CheckMemoryAccess(vaddr, 2, Kernel::DebugWatchpointType::Write) &&
+               memory.WriteExclusive16(vaddr, value, expected);
     }
     bool MemoryWriteExclusive32(u32 vaddr, u32 value, u32 expected) override {
-        return memory.WriteExclusive32(vaddr, value, expected);
+        return CheckMemoryAccess(vaddr, 4, Kernel::DebugWatchpointType::Write) &&
+               memory.WriteExclusive32(vaddr, value, expected);
     }
     bool MemoryWriteExclusive64(u32 vaddr, u64 value, u64 expected) override {
-        return memory.WriteExclusive64(vaddr, value, expected);
+        return CheckMemoryAccess(vaddr, 8, Kernel::DebugWatchpointType::Write) &&
+               memory.WriteExclusive64(vaddr, value, expected);
     }
 
     void InterpreterFallback(u32 pc, std::size_t num_instructions) override {
@@ -77,8 +94,8 @@ public:
     }
 
     void ExceptionRaised(u32 pc, Dynarmic::A32::Exception exception) override {
-        if (parent.system.DebuggerEnabled()) {
-            parent.jit.load()->Regs()[15] = pc;
+        if (debugger_enabled) {
+            parent.SaveContext(parent.breakpoint_context);
             parent.jit.load()->HaltExecution(ARM_Interface::breakpoint);
             return;
         }
@@ -117,9 +134,26 @@ public:
         return std::max<s64>(parent.system.CoreTiming().GetDowncount(), 0);
     }
 
+    bool CheckMemoryAccess(VAddr addr, u64 size, Kernel::DebugWatchpointType type) {
+        if (!debugger_enabled) {
+            return true;
+        }
+
+        const auto match{parent.MatchingWatchpoint(addr, size, type)};
+        if (match) {
+            parent.SaveContext(parent.breakpoint_context);
+            parent.jit.load()->HaltExecution(ARM_Interface::watchpoint);
+            parent.halted_watchpoint = match;
+            return false;
+        }
+
+        return true;
+    }
+
     ARM_Dynarmic_32& parent;
     Core::Memory::Memory& memory;
     std::size_t num_interpreted_instructions{};
+    bool debugger_enabled{};
     static constexpr u64 minimum_run_cycles = 1000U;
 };
 
@@ -154,6 +188,11 @@ std::shared_ptr<Dynarmic::A32::Jit> ARM_Dynarmic_32::MakeJit(Common::PageTable*
     config.code_cache_size = 512_MiB;
     config.far_code_offset = 400_MiB;
 
+    // Allow memory fault handling to work
+    if (system.DebuggerEnabled()) {
+        config.check_halt_on_memory_access = true;
+    }
+
     // null_jit
     if (!page_table) {
         // Don't waste too much memory on null_jit
@@ -248,6 +287,14 @@ u32 ARM_Dynarmic_32::GetSvcNumber() const {
     return svc_swi;
 }
 
+const Kernel::DebugWatchpoint* ARM_Dynarmic_32::HaltedWatchpoint() const {
+    return halted_watchpoint;
+}
+
+void ARM_Dynarmic_32::RewindBreakpointInstruction() {
+    LoadContext(breakpoint_context);
+}
+
 ARM_Dynarmic_32::ARM_Dynarmic_32(System& system_, CPUInterrupts& interrupt_handlers_,
                                  bool uses_wall_clock_, ExclusiveMonitor& exclusive_monitor_,
                                  std::size_t core_index_)
-- 
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