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/hle/kernel/k_process.cpp   | 46 +++++++++++++++++++++++++++++++++++++
 src/core/hle/kernel/k_process.h     | 30 ++++++++++++++++++++++++
 src/core/hle/kernel/k_scheduler.cpp |  1 +
 3 files changed, 77 insertions(+)

(limited to 'src/core/hle/kernel')

diff --git a/src/core/hle/kernel/k_process.cpp b/src/core/hle/kernel/k_process.cpp
index cd863e715..6a73f6783 100644
--- a/src/core/hle/kernel/k_process.cpp
+++ b/src/core/hle/kernel/k_process.cpp
@@ -584,6 +584,52 @@ ResultCode KProcess::DeleteThreadLocalRegion(VAddr addr) {
     return ResultSuccess;
 }
 
+bool KProcess::InsertWatchpoint(Core::System& system, VAddr addr, u64 size,
+                                DebugWatchpointType type) {
+    const auto watch{std::find_if(watchpoints.begin(), watchpoints.end(), [&](const auto& wp) {
+        return wp.type == DebugWatchpointType::None;
+    })};
+
+    if (watch == watchpoints.end()) {
+        return false;
+    }
+
+    watch->start_address = addr;
+    watch->end_address = addr + size;
+    watch->type = type;
+
+    for (VAddr page = Common::AlignDown(addr, PageSize); page < addr + size; page += PageSize) {
+        debug_page_refcounts[page]++;
+        system.Memory().MarkRegionDebug(page, PageSize, true);
+    }
+
+    return true;
+}
+
+bool KProcess::RemoveWatchpoint(Core::System& system, VAddr addr, u64 size,
+                                DebugWatchpointType type) {
+    const auto watch{std::find_if(watchpoints.begin(), watchpoints.end(), [&](const auto& wp) {
+        return wp.start_address == addr && wp.end_address == addr + size && wp.type == type;
+    })};
+
+    if (watch == watchpoints.end()) {
+        return false;
+    }
+
+    watch->start_address = 0;
+    watch->end_address = 0;
+    watch->type = DebugWatchpointType::None;
+
+    for (VAddr page = Common::AlignDown(addr, PageSize); page < addr + size; page += PageSize) {
+        debug_page_refcounts[page]--;
+        if (!debug_page_refcounts[page]) {
+            system.Memory().MarkRegionDebug(page, PageSize, false);
+        }
+    }
+
+    return true;
+}
+
 void KProcess::LoadModule(CodeSet code_set, VAddr base_addr) {
     const auto ReprotectSegment = [&](const CodeSet::Segment& segment,
                                       Svc::MemoryPermission permission) {
diff --git a/src/core/hle/kernel/k_process.h b/src/core/hle/kernel/k_process.h
index e562a79b8..c2086e5ba 100644
--- a/src/core/hle/kernel/k_process.h
+++ b/src/core/hle/kernel/k_process.h
@@ -7,6 +7,7 @@
 #include <array>
 #include <cstddef>
 #include <list>
+#include <map>
 #include <string>
 #include "common/common_types.h"
 #include "core/hle/kernel/k_address_arbiter.h"
@@ -68,6 +69,20 @@ enum class ProcessActivity : u32 {
     Paused,
 };
 
+enum class DebugWatchpointType : u8 {
+    None = 0,
+    Read = 1 << 0,
+    Write = 1 << 1,
+    ReadOrWrite = Read | Write,
+};
+DECLARE_ENUM_FLAG_OPERATORS(DebugWatchpointType);
+
+struct DebugWatchpoint {
+    VAddr start_address;
+    VAddr end_address;
+    DebugWatchpointType type;
+};
+
 class KProcess final : public KAutoObjectWithSlabHeapAndContainer<KProcess, KWorkerTask> {
     KERNEL_AUTOOBJECT_TRAITS(KProcess, KSynchronizationObject);
 
@@ -374,6 +389,19 @@ public:
     // Frees a used TLS slot identified by the given address
     ResultCode DeleteThreadLocalRegion(VAddr addr);
 
+    ///////////////////////////////////////////////////////////////////////////////////////////////
+    // Debug watchpoint management
+
+    // Attempts to insert a watchpoint into a free slot. Returns false if none are available.
+    bool InsertWatchpoint(Core::System& system, VAddr addr, u64 size, DebugWatchpointType type);
+
+    // Attempts to remove the watchpoint specified by the given parameters.
+    bool RemoveWatchpoint(Core::System& system, VAddr addr, u64 size, DebugWatchpointType type);
+
+    const std::array<DebugWatchpoint, Core::Hardware::NUM_WATCHPOINTS>& GetWatchpoints() const {
+        return watchpoints;
+    }
+
 private:
     void PinThread(s32 core_id, KThread* thread) {
         ASSERT(0 <= core_id && core_id < static_cast<s32>(Core::Hardware::NUM_CPU_CORES));
@@ -478,6 +506,8 @@ private:
     std::array<KThread*, Core::Hardware::NUM_CPU_CORES> running_threads{};
     std::array<u64, Core::Hardware::NUM_CPU_CORES> running_thread_idle_counts{};
     std::array<KThread*, Core::Hardware::NUM_CPU_CORES> pinned_threads{};
+    std::array<DebugWatchpoint, Core::Hardware::NUM_WATCHPOINTS> watchpoints{};
+    std::map<VAddr, u64> debug_page_refcounts;
 
     KThread* exception_thread{};
 
diff --git a/src/core/hle/kernel/k_scheduler.cpp b/src/core/hle/kernel/k_scheduler.cpp
index 2d4e8637b..edd0e4eae 100644
--- a/src/core/hle/kernel/k_scheduler.cpp
+++ b/src/core/hle/kernel/k_scheduler.cpp
@@ -710,6 +710,7 @@ void KScheduler::Reload(KThread* thread) {
     Core::ARM_Interface& cpu_core = system.ArmInterface(core_id);
     cpu_core.LoadContext(thread->GetContext32());
     cpu_core.LoadContext(thread->GetContext64());
+    cpu_core.LoadWatchpointArray(thread->GetOwnerProcess()->GetWatchpoints());
     cpu_core.SetTlsAddress(thread->GetTLSAddress());
     cpu_core.SetTPIDR_EL0(thread->GetTPIDR_EL0());
     cpu_core.ClearExclusiveState();
-- 
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