diff --git a/src/dynarmic/CMakeLists.txt b/src/dynarmic/CMakeLists.txt
index 2e8273ec..126b9dba 100644
--- a/src/dynarmic/CMakeLists.txt
+++ b/src/dynarmic/CMakeLists.txt
@@ -58,6 +58,7 @@ add_library(dynarmic
     common/memory_pool.h
     common/safe_ops.h
     common/scope_exit.h
+    common/spin_lock.h
     common/string_util.h
     common/u128.cpp
     common/u128.h
@@ -281,6 +282,7 @@ if (ARCHITECTURE STREQUAL "x86_64")
         backend/x64/emit_x64_crc32.cpp
         backend/x64/emit_x64_data_processing.cpp
         backend/x64/emit_x64_floating_point.cpp
+        backend/x64/emit_x64_memory.h
         backend/x64/emit_x64_packed.cpp
         backend/x64/emit_x64_saturation.cpp
         backend/x64/emit_x64_sm4.cpp
@@ -289,6 +291,7 @@ if (ARCHITECTURE STREQUAL "x86_64")
         backend/x64/emit_x64_vector_saturation.cpp
         backend/x64/exception_handler.h
         backend/x64/exclusive_monitor.cpp
+        backend/x64/exclusive_monitor_friend.h
         backend/x64/host_feature.h
         backend/x64/hostloc.cpp
         backend/x64/hostloc.h
@@ -299,6 +302,8 @@ if (ARCHITECTURE STREQUAL "x86_64")
         backend/x64/reg_alloc.cpp
         backend/x64/reg_alloc.h
         backend/x64/stack_layout.h
+        common/spin_lock_x64.cpp
+        common/spin_lock_x64.h
     )
 
     if ("A32" IN_LIST DYNARMIC_FRONTENDS)
diff --git a/src/dynarmic/backend/x64/a32_emit_x64.h b/src/dynarmic/backend/x64/a32_emit_x64.h
index 6684835f..43f90f6a 100644
--- a/src/dynarmic/backend/x64/a32_emit_x64.h
+++ b/src/dynarmic/backend/x64/a32_emit_x64.h
@@ -73,6 +73,7 @@ protected:
 
     std::map<std::tuple<size_t, int, int>, void (*)()> read_fallbacks;
     std::map<std::tuple<size_t, int, int>, void (*)()> write_fallbacks;
+    std::map<std::tuple<size_t, int, int>, void (*)()> exclusive_write_fallbacks;
     void GenFastmemFallbacks();
 
     const void* terminal_handler_pop_rsb_hint;
@@ -98,6 +99,7 @@ protected:
         u64 resume_rip;
         u64 callback;
         DoNotFastmemMarker marker;
+        bool compile;
     };
     tsl::robin_map<u64, FastmemPatchInfo> fastmem_patch_info;
     std::set<DoNotFastmemMarker> do_not_fastmem;
@@ -113,6 +115,10 @@ protected:
     void ExclusiveReadMemory(A32EmitContext& ctx, IR::Inst* inst);
     template<std::size_t bitsize, auto callback>
     void ExclusiveWriteMemory(A32EmitContext& ctx, IR::Inst* inst);
+    template<std::size_t bitsize, auto callback>
+    void ExclusiveReadMemoryInline(A32EmitContext& ctx, IR::Inst* inst);
+    template<std::size_t bitsize, auto callback>
+    void ExclusiveWriteMemoryInline(A32EmitContext& ctx, IR::Inst* inst);
 
     // Terminal instruction emitters
     void EmitSetUpperLocationDescriptor(IR::LocationDescriptor new_location, IR::LocationDescriptor old_location);
diff --git a/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp b/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp
index 804a114a..33f1ddfc 100644
--- a/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp
+++ b/src/dynarmic/backend/x64/a32_emit_x64_memory.cpp
@@ -16,6 +16,8 @@
 #include "dynarmic/backend/x64/a32_emit_x64.h"
 #include "dynarmic/backend/x64/abi.h"
 #include "dynarmic/backend/x64/devirtualize.h"
+#include "dynarmic/backend/x64/emit_x64_memory.h"
+#include "dynarmic/backend/x64/exclusive_monitor_friend.h"
 #include "dynarmic/backend/x64/perf_map.h"
 #include "dynarmic/common/x64_disassemble.h"
 #include "dynarmic/interface/exclusive_monitor.h"
@@ -38,6 +40,12 @@ void A32EmitX64::GenFastmemFallbacks() {
         {32, Devirtualize<&A32::UserCallbacks::MemoryWrite32>(conf.callbacks)},
         {64, Devirtualize<&A32::UserCallbacks::MemoryWrite64>(conf.callbacks)},
     }};
+    const std::array<std::pair<size_t, ArgCallback>, 4> exclusive_write_callbacks{{
+        {8, Devirtualize<&A32::UserCallbacks::MemoryWriteExclusive8>(conf.callbacks)},
+        {16, Devirtualize<&A32::UserCallbacks::MemoryWriteExclusive16>(conf.callbacks)},
+        {32, Devirtualize<&A32::UserCallbacks::MemoryWriteExclusive32>(conf.callbacks)},
+        {64, Devirtualize<&A32::UserCallbacks::MemoryWriteExclusive64>(conf.callbacks)},
+    }};
 
     for (int vaddr_idx : idxes) {
         for (int value_idx : idxes) {
@@ -82,6 +90,32 @@ void A32EmitX64::GenFastmemFallbacks() {
                 code.ret();
                 PerfMapRegister(write_fallbacks[std::make_tuple(bitsize, vaddr_idx, value_idx)], code.getCurr(), fmt::format("a32_write_fallback_{}", bitsize));
             }
+
+            for (const auto& [bitsize, callback] : exclusive_write_callbacks) {
+                code.align();
+                exclusive_write_fallbacks[std::make_tuple(bitsize, vaddr_idx, value_idx)] = code.getCurr<void (*)()>();
+                ABI_PushCallerSaveRegistersAndAdjustStackExcept(code, HostLoc::RAX);
+                if (vaddr_idx == code.ABI_PARAM3.getIdx() && value_idx == code.ABI_PARAM2.getIdx()) {
+                    code.xchg(code.ABI_PARAM2, code.ABI_PARAM3);
+                } else if (vaddr_idx == code.ABI_PARAM3.getIdx()) {
+                    code.mov(code.ABI_PARAM2, Xbyak::Reg64{vaddr_idx});
+                    if (value_idx != code.ABI_PARAM3.getIdx()) {
+                        code.mov(code.ABI_PARAM3, Xbyak::Reg64{value_idx});
+                    }
+                } else {
+                    if (value_idx != code.ABI_PARAM3.getIdx()) {
+                        code.mov(code.ABI_PARAM3, Xbyak::Reg64{value_idx});
+                    }
+                    if (vaddr_idx != code.ABI_PARAM2.getIdx()) {
+                        code.mov(code.ABI_PARAM2, Xbyak::Reg64{vaddr_idx});
+                    }
+                }
+                code.mov(code.ABI_PARAM4, rax);
+                callback.EmitCall(code);
+                ABI_PopCallerSaveRegistersAndAdjustStackExcept(code, HostLoc::RAX);
+                code.ret();
+                PerfMapRegister(exclusive_write_fallbacks[std::make_tuple(bitsize, vaddr_idx, value_idx)], code.getCurr(), fmt::format("a32_exclusive_write_fallback_{}", bitsize));
+            }
         }
     }
 }
@@ -109,15 +143,16 @@ FakeCall A32EmitX64::FastmemCallback(u64 rip_) {
         ASSERT_FALSE("iter != fastmem_patch_info.end()");
     }
 
-    if (conf.recompile_on_fastmem_failure) {
+    if (iter->second.compile) {
         const auto marker = iter->second.marker;
         do_not_fastmem.emplace(marker);
         InvalidateBasicBlocks({std::get<0>(marker)});
     }
-    FakeCall ret;
-    ret.call_rip = iter->second.callback;
-    ret.ret_rip = iter->second.resume_rip;
-    return ret;
+
+    return FakeCall{
+        .call_rip = iter->second.callback,
+        .ret_rip = iter->second.resume_rip,
+    };
 }
 
 namespace {
@@ -265,6 +300,7 @@ void A32EmitX64::EmitMemoryRead(A32EmitContext& ctx, IR::Inst* inst) {
                 Common::BitCast<u64>(code.getCurr()),
                 Common::BitCast<u64>(wrapped_fn),
                 *fastmem_marker,
+                conf.recompile_on_fastmem_failure,
             });
 
         ctx.reg_alloc.DefineValue(inst, value);
@@ -318,6 +354,7 @@ void A32EmitX64::EmitMemoryWrite(A32EmitContext& ctx, IR::Inst* inst) {
                 Common::BitCast<u64>(code.getCurr()),
                 Common::BitCast<u64>(wrapped_fn),
                 *fastmem_marker,
+                conf.recompile_on_fastmem_failure,
             });
 
         return;
@@ -418,40 +455,221 @@ void A32EmitX64::ExclusiveWriteMemory(A32EmitContext& ctx, IR::Inst* inst) {
     code.L(end);
 }
 
+template<std::size_t bitsize, auto callback>
+void A32EmitX64::ExclusiveReadMemoryInline(A32EmitContext& ctx, IR::Inst* inst) {
+    ASSERT(conf.global_monitor && conf.fastmem_pointer);
+    if (!exception_handler.SupportsFastmem()) {
+        ExclusiveReadMemory<bitsize, callback>(ctx, inst);
+        return;
+    }
+
+    auto args = ctx.reg_alloc.GetArgumentInfo(inst);
+
+    const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
+    const Xbyak::Reg64 value = ctx.reg_alloc.ScratchGpr();
+    const Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
+    const Xbyak::Reg64 tmp2 = ctx.reg_alloc.ScratchGpr();
+
+    const auto wrapped_fn = read_fallbacks[std::make_tuple(bitsize, vaddr.getIdx(), value.getIdx())];
+
+    EmitExclusiveLock(code, conf, tmp, tmp2.cvt32());
+
+    code.mov(code.byte[r15 + offsetof(A32JitState, exclusive_state)], u8(1));
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorAddressPointer(conf.global_monitor, conf.processor_id)));
+    code.mov(qword[tmp], vaddr);
+
+    const auto fastmem_marker = ShouldFastmem(ctx, inst);
+    if (fastmem_marker) {
+        Xbyak::Label end;
+
+        const auto src_ptr = r13 + vaddr;
+
+        const auto location = code.getCurr();
+        EmitReadMemoryMov<bitsize>(code, value, src_ptr);
+
+        fastmem_patch_info.emplace(
+            Common::BitCast<u64>(location),
+            FastmemPatchInfo{
+                Common::BitCast<u64>(code.getCurr()),
+                Common::BitCast<u64>(wrapped_fn),
+                *fastmem_marker,
+                conf.recompile_on_exclusive_fastmem_failure,
+            });
+
+        code.L(end);
+    } else {
+        code.call(wrapped_fn);
+    }
+
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorValuePointer(conf.global_monitor, conf.processor_id)));
+    EmitWriteMemoryMov<bitsize>(code, tmp, value);
+
+    EmitExclusiveUnlock(code, conf, tmp, tmp2.cvt32());
+
+    ctx.reg_alloc.DefineValue(inst, value);
+}
+
+template<std::size_t bitsize, auto callback>
+void A32EmitX64::ExclusiveWriteMemoryInline(A32EmitContext& ctx, IR::Inst* inst) {
+    ASSERT(conf.global_monitor && conf.fastmem_pointer);
+    if (!exception_handler.SupportsFastmem()) {
+        ExclusiveWriteMemory<bitsize, callback>(ctx, inst);
+        return;
+    }
+
+    auto args = ctx.reg_alloc.GetArgumentInfo(inst);
+
+    ctx.reg_alloc.ScratchGpr(HostLoc::RAX);
+    const Xbyak::Reg64 value = ctx.reg_alloc.UseGpr(args[1]);
+    const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
+    const Xbyak::Reg32 status = ctx.reg_alloc.ScratchGpr().cvt32();
+    const Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
+
+    const auto fallback_fn = exclusive_write_fallbacks[std::make_tuple(bitsize, vaddr.getIdx(), value.getIdx())];
+
+    EmitExclusiveLock(code, conf, tmp, eax);
+
+    Xbyak::Label end;
+
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorAddressPointer(conf.global_monitor, conf.processor_id)));
+    code.mov(status, u32(1));
+    code.cmp(code.byte[r15 + offsetof(A32JitState, exclusive_state)], u8(0));
+    code.je(end, code.T_NEAR);
+    code.cmp(qword[tmp], vaddr);
+    code.jne(end, code.T_NEAR);
+
+    EmitExclusiveTestAndClear(code, conf, vaddr, tmp, rax);
+
+    code.mov(code.byte[r15 + offsetof(A32JitState, exclusive_state)], u8(0));
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorValuePointer(conf.global_monitor, conf.processor_id)));
+
+    EmitReadMemoryMov<bitsize>(code, rax, tmp);
+
+    const auto fastmem_marker = ShouldFastmem(ctx, inst);
+    if (fastmem_marker) {
+        const auto dest_ptr = r13 + vaddr;
+
+        const auto location = code.getCurr();
+
+        switch (bitsize) {
+        case 8:
+            code.lock();
+            code.cmpxchg(code.byte[dest_ptr], value.cvt8());
+            break;
+        case 16:
+            code.lock();
+            code.cmpxchg(word[dest_ptr], value.cvt16());
+            break;
+        case 32:
+            code.lock();
+            code.cmpxchg(dword[dest_ptr], value.cvt32());
+            break;
+        case 64:
+            code.lock();
+            code.cmpxchg(qword[dest_ptr], value.cvt64());
+            break;
+        default:
+            UNREACHABLE();
+        }
+
+        code.setnz(status.cvt8());
+
+        code.SwitchToFarCode();
+
+        fastmem_patch_info.emplace(
+            Common::BitCast<u64>(location),
+            FastmemPatchInfo{
+                Common::BitCast<u64>(code.getCurr()),
+                Common::BitCast<u64>(fallback_fn),
+                *fastmem_marker,
+                conf.recompile_on_exclusive_fastmem_failure,
+            });
+
+        code.cmp(al, 0);
+        code.setz(status.cvt8());
+        code.movzx(status.cvt32(), status.cvt8());
+        code.jmp(end, code.T_NEAR);
+        code.SwitchToNearCode();
+    } else {
+        code.call(fallback_fn);
+        code.cmp(al, 0);
+        code.setz(status.cvt8());
+        code.movzx(status.cvt32(), status.cvt8());
+    }
+
+    code.L(end);
+
+    EmitExclusiveUnlock(code, conf, tmp, eax);
+
+    ctx.reg_alloc.DefineValue(inst, status);
+}
+
 void A32EmitX64::EmitA32ClearExclusive(A32EmitContext&, IR::Inst*) {
     code.mov(code.byte[r15 + offsetof(A32JitState, exclusive_state)], u8(0));
 }
 
 void A32EmitX64::EmitA32ExclusiveReadMemory8(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveReadMemory<8, &A32::UserCallbacks::MemoryRead8>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveReadMemoryInline<8, &A32::UserCallbacks::MemoryRead8>(ctx, inst);
+    } else {
+        ExclusiveReadMemory<8, &A32::UserCallbacks::MemoryRead8>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveReadMemory16(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveReadMemory<16, &A32::UserCallbacks::MemoryRead16>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveReadMemoryInline<16, &A32::UserCallbacks::MemoryRead16>(ctx, inst);
+    } else {
+        ExclusiveReadMemory<16, &A32::UserCallbacks::MemoryRead16>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveReadMemory32(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveReadMemory<32, &A32::UserCallbacks::MemoryRead32>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveReadMemoryInline<32, &A32::UserCallbacks::MemoryRead32>(ctx, inst);
+    } else {
+        ExclusiveReadMemory<32, &A32::UserCallbacks::MemoryRead32>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveReadMemory64(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveReadMemory<64, &A32::UserCallbacks::MemoryRead64>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveReadMemoryInline<64, &A32::UserCallbacks::MemoryRead64>(ctx, inst);
+    } else {
+        ExclusiveReadMemory<64, &A32::UserCallbacks::MemoryRead64>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveWriteMemory8(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveWriteMemory<8, &A32::UserCallbacks::MemoryWriteExclusive8>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveWriteMemoryInline<8, &A32::UserCallbacks::MemoryWriteExclusive8>(ctx, inst);
+    } else {
+        ExclusiveWriteMemory<8, &A32::UserCallbacks::MemoryWriteExclusive8>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveWriteMemory16(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveWriteMemory<16, &A32::UserCallbacks::MemoryWriteExclusive16>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveWriteMemoryInline<16, &A32::UserCallbacks::MemoryWriteExclusive16>(ctx, inst);
+    } else {
+        ExclusiveWriteMemory<16, &A32::UserCallbacks::MemoryWriteExclusive16>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveWriteMemory32(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveWriteMemory<32, &A32::UserCallbacks::MemoryWriteExclusive32>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveWriteMemoryInline<32, &A32::UserCallbacks::MemoryWriteExclusive32>(ctx, inst);
+    } else {
+        ExclusiveWriteMemory<32, &A32::UserCallbacks::MemoryWriteExclusive32>(ctx, inst);
+    }
 }
 
 void A32EmitX64::EmitA32ExclusiveWriteMemory64(A32EmitContext& ctx, IR::Inst* inst) {
-    ExclusiveWriteMemory<64, &A32::UserCallbacks::MemoryWriteExclusive64>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        ExclusiveWriteMemoryInline<64, &A32::UserCallbacks::MemoryWriteExclusive64>(ctx, inst);
+    } else {
+        ExclusiveWriteMemory<64, &A32::UserCallbacks::MemoryWriteExclusive64>(ctx, inst);
+    }
 }
 
 }  // namespace Dynarmic::Backend::X64
diff --git a/src/dynarmic/backend/x64/a64_emit_x64.h b/src/dynarmic/backend/x64/a64_emit_x64.h
index 32ab24e8..cbfa28bd 100644
--- a/src/dynarmic/backend/x64/a64_emit_x64.h
+++ b/src/dynarmic/backend/x64/a64_emit_x64.h
@@ -7,6 +7,7 @@
 
 #include <array>
 #include <map>
+#include <optional>
 #include <tuple>
 
 #include "dynarmic/backend/x64/a64_jitstate.h"
@@ -67,10 +68,12 @@ protected:
 
     void (*memory_read_128)();
     void (*memory_write_128)();
+    void (*memory_exclusive_write_128)();
     void GenMemory128Accessors();
 
     std::map<std::tuple<size_t, int, int>, void (*)()> read_fallbacks;
     std::map<std::tuple<size_t, int, int>, void (*)()> write_fallbacks;
+    std::map<std::tuple<size_t, int, int>, void (*)()> exclusive_write_fallbacks;
     void GenFastmemFallbacks();
 
     const void* terminal_handler_pop_rsb_hint;
@@ -97,6 +100,7 @@ protected:
         u64 resume_rip;
         u64 callback;
         DoNotFastmemMarker marker;
+        bool recompile;
     };
     tsl::robin_map<u64, FastmemPatchInfo> fastmem_patch_info;
     std::set<DoNotFastmemMarker> do_not_fastmem;
@@ -112,6 +116,10 @@ protected:
     void EmitExclusiveReadMemory(A64EmitContext& ctx, IR::Inst* inst);
     template<std::size_t bitsize, auto callback>
     void EmitExclusiveWriteMemory(A64EmitContext& ctx, IR::Inst* inst);
+    template<std::size_t bitsize, auto callback>
+    void EmitExclusiveReadMemoryInline(A64EmitContext& ctx, IR::Inst* inst);
+    template<std::size_t bitsize, auto callback>
+    void EmitExclusiveWriteMemoryInline(A64EmitContext& ctx, IR::Inst* inst);
 
     // Terminal instruction emitters
     void EmitTerminalImpl(IR::Term::Interpret terminal, IR::LocationDescriptor initial_location, bool is_single_step) override;
diff --git a/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp b/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp
index 29aeaf01..0b2b6977 100644
--- a/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp
+++ b/src/dynarmic/backend/x64/a64_emit_x64_memory.cpp
@@ -16,7 +16,10 @@
 #include "dynarmic/backend/x64/a64_emit_x64.h"
 #include "dynarmic/backend/x64/abi.h"
 #include "dynarmic/backend/x64/devirtualize.h"
+#include "dynarmic/backend/x64/emit_x64_memory.h"
+#include "dynarmic/backend/x64/exclusive_monitor_friend.h"
 #include "dynarmic/backend/x64/perf_map.h"
+#include "dynarmic/common/spin_lock_x64.h"
 #include "dynarmic/common/x64_disassemble.h"
 #include "dynarmic/interface/exclusive_monitor.h"
 
@@ -73,7 +76,38 @@ void A64EmitX64::GenMemory128Accessors() {
     code.add(rsp, 8);
 #endif
     code.ret();
-    PerfMapRegister(memory_read_128, code.getCurr(), "a64_memory_write_128");
+    PerfMapRegister(memory_write_128, code.getCurr(), "a64_memory_write_128");
+
+    code.align();
+    memory_exclusive_write_128 = code.getCurr<void (*)()>();
+#ifdef _WIN32
+    code.sub(rsp, 8 + 32 + ABI_SHADOW_SPACE);
+    code.lea(code.ABI_PARAM3, ptr[rsp + ABI_SHADOW_SPACE]);
+    code.lea(code.ABI_PARAM4, ptr[rsp + ABI_SHADOW_SPACE + 16]);
+    code.movaps(xword[code.ABI_PARAM3], xmm1);
+    code.movaps(xword[code.ABI_PARAM4], xmm2);
+    Devirtualize<&A64::UserCallbacks::MemoryWriteExclusive128>(conf.callbacks).EmitCall(code);
+    code.add(rsp, 8 + 16 + ABI_SHADOW_SPACE);
+#else
+    code.sub(rsp, 8);
+    if (code.HasHostFeature(HostFeature::SSE41)) {
+        code.movq(code.ABI_PARAM3, xmm1);
+        code.pextrq(code.ABI_PARAM4, xmm1, 1);
+        code.movq(code.ABI_PARAM5, xmm2);
+        code.pextrq(code.ABI_PARAM6, xmm2, 1);
+    } else {
+        code.movq(code.ABI_PARAM3, xmm1);
+        code.punpckhqdq(xmm1, xmm1);
+        code.movq(code.ABI_PARAM4, xmm1);
+        code.movq(code.ABI_PARAM5, xmm2);
+        code.punpckhqdq(xmm2, xmm2);
+        code.movq(code.ABI_PARAM6, xmm2);
+    }
+    Devirtualize<&A64::UserCallbacks::MemoryWriteExclusive128>(conf.callbacks).EmitCall(code);
+    code.add(rsp, 8);
+#endif
+    code.ret();
+    PerfMapRegister(memory_exclusive_write_128, code.getCurr(), "a64_memory_exclusive_write_128");
 }
 
 void A64EmitX64::GenFastmemFallbacks() {
@@ -90,6 +124,12 @@ void A64EmitX64::GenFastmemFallbacks() {
         {32, Devirtualize<&A64::UserCallbacks::MemoryWrite32>(conf.callbacks)},
         {64, Devirtualize<&A64::UserCallbacks::MemoryWrite64>(conf.callbacks)},
     }};
+    const std::array<std::pair<size_t, ArgCallback>, 4> exclusive_write_callbacks{{
+        {8, Devirtualize<&A64::UserCallbacks::MemoryWriteExclusive8>(conf.callbacks)},
+        {16, Devirtualize<&A64::UserCallbacks::MemoryWriteExclusive16>(conf.callbacks)},
+        {32, Devirtualize<&A64::UserCallbacks::MemoryWriteExclusive32>(conf.callbacks)},
+        {64, Devirtualize<&A64::UserCallbacks::MemoryWriteExclusive64>(conf.callbacks)},
+    }};
 
     for (int vaddr_idx : idxes) {
         if (vaddr_idx == 4 || vaddr_idx == 15) {
@@ -125,6 +165,28 @@ void A64EmitX64::GenFastmemFallbacks() {
             code.ret();
             PerfMapRegister(write_fallbacks[std::make_tuple(128, vaddr_idx, value_idx)], code.getCurr(), "a64_write_fallback_128");
 
+            code.align();
+            exclusive_write_fallbacks[std::make_tuple(128, vaddr_idx, value_idx)] = code.getCurr<void (*)()>();
+            ABI_PushCallerSaveRegistersAndAdjustStack(code);
+            if (value_idx != 1) {
+                code.movaps(xmm1, Xbyak::Xmm{value_idx});
+            }
+            if (code.HasHostFeature(HostFeature::SSE41)) {
+                code.movq(xmm2, rax);
+                code.pinsrq(xmm2, rdx, 1);
+            } else {
+                code.movq(xmm2, rax);
+                code.movq(xmm0, rdx);
+                code.punpcklqdq(xmm2, xmm0);
+            }
+            if (vaddr_idx != code.ABI_PARAM2.getIdx()) {
+                code.mov(code.ABI_PARAM2, Xbyak::Reg64{vaddr_idx});
+            }
+            code.call(memory_exclusive_write_128);
+            ABI_PopCallerSaveRegistersAndAdjustStack(code);
+            code.ret();
+            PerfMapRegister(exclusive_write_fallbacks[std::make_tuple(128, vaddr_idx, value_idx)], code.getCurr(), "a64_write_fallback_128");
+
             if (value_idx == 4 || value_idx == 15) {
                 continue;
             }
@@ -170,6 +232,32 @@ void A64EmitX64::GenFastmemFallbacks() {
                 code.ret();
                 PerfMapRegister(write_fallbacks[std::make_tuple(bitsize, vaddr_idx, value_idx)], code.getCurr(), fmt::format("a64_write_fallback_{}", bitsize));
             }
+
+            for (const auto& [bitsize, callback] : exclusive_write_callbacks) {
+                code.align();
+                exclusive_write_fallbacks[std::make_tuple(bitsize, vaddr_idx, value_idx)] = code.getCurr<void (*)()>();
+                ABI_PushCallerSaveRegistersAndAdjustStackExcept(code, HostLoc::RAX);
+                if (vaddr_idx == code.ABI_PARAM3.getIdx() && value_idx == code.ABI_PARAM2.getIdx()) {
+                    code.xchg(code.ABI_PARAM2, code.ABI_PARAM3);
+                } else if (vaddr_idx == code.ABI_PARAM3.getIdx()) {
+                    code.mov(code.ABI_PARAM2, Xbyak::Reg64{vaddr_idx});
+                    if (value_idx != code.ABI_PARAM3.getIdx()) {
+                        code.mov(code.ABI_PARAM3, Xbyak::Reg64{value_idx});
+                    }
+                } else {
+                    if (value_idx != code.ABI_PARAM3.getIdx()) {
+                        code.mov(code.ABI_PARAM3, Xbyak::Reg64{value_idx});
+                    }
+                    if (vaddr_idx != code.ABI_PARAM2.getIdx()) {
+                        code.mov(code.ABI_PARAM2, Xbyak::Reg64{vaddr_idx});
+                    }
+                }
+                code.mov(code.ABI_PARAM4, rax);
+                callback.EmitCall(code);
+                ABI_PopCallerSaveRegistersAndAdjustStackExcept(code, HostLoc::RAX);
+                code.ret();
+                PerfMapRegister(exclusive_write_fallbacks[std::make_tuple(bitsize, vaddr_idx, value_idx)], code.getCurr(), fmt::format("a64_exclusive_write_fallback_{}", bitsize));
+            }
         }
     }
 }
@@ -197,15 +285,16 @@ FakeCall A64EmitX64::FastmemCallback(u64 rip_) {
         ASSERT_FALSE("iter != fastmem_patch_info.end()");
     }
 
-    if (conf.recompile_on_fastmem_failure) {
+    if (iter->second.recompile) {
         const auto marker = iter->second.marker;
         do_not_fastmem.emplace(marker);
         InvalidateBasicBlocks({std::get<0>(marker)});
     }
-    FakeCall ret;
-    ret.call_rip = iter->second.callback;
-    ret.ret_rip = iter->second.resume_rip;
-    return ret;
+
+    return FakeCall{
+        .call_rip = iter->second.callback,
+        .ret_rip = iter->second.resume_rip,
+    };
 }
 
 namespace {
@@ -309,24 +398,26 @@ Xbyak::RegExp EmitVAddrLookup(BlockOfCode& code, A64EmitContext& ctx, size_t bit
     return page + tmp;
 }
 
-Xbyak::RegExp EmitFastmemVAddr(BlockOfCode& code, A64EmitContext& ctx, Xbyak::Label& abort, Xbyak::Reg64 vaddr, bool& require_abort_handling) {
+Xbyak::RegExp EmitFastmemVAddr(BlockOfCode& code, A64EmitContext& ctx, Xbyak::Label& abort, Xbyak::Reg64 vaddr, bool& require_abort_handling, std::optional<Xbyak::Reg64> tmp = std::nullopt) {
     const size_t unused_top_bits = 64 - ctx.conf.fastmem_address_space_bits;
 
     if (unused_top_bits == 0) {
         return r13 + vaddr;
     } else if (ctx.conf.silently_mirror_fastmem) {
-        Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
-        if (unused_top_bits < 32) {
-            code.mov(tmp, vaddr);
-            code.shl(tmp, int(unused_top_bits));
-            code.shr(tmp, int(unused_top_bits));
-        } else if (unused_top_bits == 32) {
-            code.mov(tmp.cvt32(), vaddr.cvt32());
-        } else {
-            code.mov(tmp.cvt32(), vaddr.cvt32());
-            code.and_(tmp, u32((1 << ctx.conf.fastmem_address_space_bits) - 1));
+        if (!tmp) {
+            tmp = ctx.reg_alloc.ScratchGpr();
         }
-        return r13 + tmp;
+        if (unused_top_bits < 32) {
+            code.mov(*tmp, vaddr);
+            code.shl(*tmp, int(unused_top_bits));
+            code.shr(*tmp, int(unused_top_bits));
+        } else if (unused_top_bits == 32) {
+            code.mov(tmp->cvt32(), vaddr.cvt32());
+        } else {
+            code.mov(tmp->cvt32(), vaddr.cvt32());
+            code.and_(*tmp, u32((1 << ctx.conf.fastmem_address_space_bits) - 1));
+        }
+        return r13 + *tmp;
     } else {
         if (ctx.conf.fastmem_address_space_bits < 32) {
             code.test(vaddr, u32(-(1 << ctx.conf.fastmem_address_space_bits)));
@@ -334,9 +425,11 @@ Xbyak::RegExp EmitFastmemVAddr(BlockOfCode& code, A64EmitContext& ctx, Xbyak::La
             require_abort_handling = true;
         } else {
             // TODO: Consider having TEST as above but coalesce 64-bit constant in register allocator
-            Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
-            code.mov(tmp, vaddr);
-            code.shr(tmp, int(ctx.conf.fastmem_address_space_bits));
+            if (!tmp) {
+                tmp = ctx.reg_alloc.ScratchGpr();
+            }
+            code.mov(*tmp, vaddr);
+            code.shr(*tmp, int(ctx.conf.fastmem_address_space_bits));
             code.jnz(abort, code.T_NEAR);
             require_abort_handling = true;
         }
@@ -432,6 +525,7 @@ void A64EmitX64::EmitMemoryRead(A64EmitContext& ctx, IR::Inst* inst) {
                 Common::BitCast<u64>(code.getCurr()),
                 Common::BitCast<u64>(wrapped_fn),
                 *fastmem_marker,
+                conf.recompile_on_fastmem_failure,
             });
     } else {
         // Use page table
@@ -498,6 +592,7 @@ void A64EmitX64::EmitMemoryWrite(A64EmitContext& ctx, IR::Inst* inst) {
                 Common::BitCast<u64>(code.getCurr()),
                 Common::BitCast<u64>(wrapped_fn),
                 *fastmem_marker,
+                conf.recompile_on_fastmem_failure,
             });
     } else {
         // Use page table
@@ -650,48 +745,284 @@ void A64EmitX64::EmitExclusiveWriteMemory(A64EmitContext& ctx, IR::Inst* inst) {
     code.L(end);
 }
 
+template<std::size_t bitsize, auto callback>
+void A64EmitX64::EmitExclusiveReadMemoryInline(A64EmitContext& ctx, IR::Inst* inst) {
+    ASSERT(conf.global_monitor && conf.fastmem_pointer);
+    if (!exception_handler.SupportsFastmem()) {
+        EmitExclusiveReadMemory<bitsize, callback>(ctx, inst);
+        return;
+    }
+
+    auto args = ctx.reg_alloc.GetArgumentInfo(inst);
+
+    const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
+    const int value_idx = bitsize == 128 ? ctx.reg_alloc.ScratchXmm().getIdx() : ctx.reg_alloc.ScratchGpr().getIdx();
+    const Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
+    const Xbyak::Reg64 tmp2 = ctx.reg_alloc.ScratchGpr();
+
+    const auto wrapped_fn = read_fallbacks[std::make_tuple(bitsize, vaddr.getIdx(), value_idx)];
+
+    EmitExclusiveLock(code, conf, tmp, tmp2.cvt32());
+
+    code.mov(code.byte[r15 + offsetof(A64JitState, exclusive_state)], u8(1));
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorAddressPointer(conf.global_monitor, conf.processor_id)));
+    code.mov(qword[tmp], vaddr);
+
+    const auto fastmem_marker = ShouldFastmem(ctx, inst);
+    if (fastmem_marker) {
+        Xbyak::Label abort, end;
+        bool require_abort_handling = false;
+
+        const auto src_ptr = EmitFastmemVAddr(code, ctx, abort, vaddr, require_abort_handling);
+
+        const auto location = code.getCurr();
+        EmitReadMemoryMov<bitsize>(code, value_idx, src_ptr);
+
+        fastmem_patch_info.emplace(
+            Common::BitCast<u64>(location),
+            FastmemPatchInfo{
+                Common::BitCast<u64>(code.getCurr()),
+                Common::BitCast<u64>(wrapped_fn),
+                *fastmem_marker,
+                conf.recompile_on_exclusive_fastmem_failure,
+            });
+
+        code.L(end);
+
+        if (require_abort_handling) {
+            code.SwitchToFarCode();
+            code.L(abort);
+            code.call(wrapped_fn);
+            code.jmp(end, code.T_NEAR);
+            code.SwitchToNearCode();
+        }
+    } else {
+        code.call(wrapped_fn);
+    }
+
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorValuePointer(conf.global_monitor, conf.processor_id)));
+    EmitWriteMemoryMov<bitsize>(code, tmp, value_idx);
+
+    EmitExclusiveUnlock(code, conf, tmp, tmp2.cvt32());
+
+    if constexpr (bitsize == 128) {
+        ctx.reg_alloc.DefineValue(inst, Xbyak::Xmm{value_idx});
+    } else {
+        ctx.reg_alloc.DefineValue(inst, Xbyak::Reg64{value_idx});
+    }
+}
+
+template<std::size_t bitsize, auto callback>
+void A64EmitX64::EmitExclusiveWriteMemoryInline(A64EmitContext& ctx, IR::Inst* inst) {
+    ASSERT(conf.global_monitor && conf.fastmem_pointer);
+    if (!exception_handler.SupportsFastmem()) {
+        EmitExclusiveWriteMemory<bitsize, callback>(ctx, inst);
+        return;
+    }
+
+    auto args = ctx.reg_alloc.GetArgumentInfo(inst);
+
+    const auto value = [&] {
+        if constexpr (bitsize == 128) {
+            ctx.reg_alloc.ScratchGpr(HostLoc::RAX);
+            ctx.reg_alloc.ScratchGpr(HostLoc::RBX);
+            ctx.reg_alloc.ScratchGpr(HostLoc::RCX);
+            ctx.reg_alloc.ScratchGpr(HostLoc::RDX);
+            return ctx.reg_alloc.UseXmm(args[1]);
+        } else {
+            ctx.reg_alloc.ScratchGpr(HostLoc::RAX);
+            return ctx.reg_alloc.UseGpr(args[1]);
+        }
+    }();
+    const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
+    const Xbyak::Reg32 status = ctx.reg_alloc.ScratchGpr().cvt32();
+    const Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
+
+    const auto fallback_fn = exclusive_write_fallbacks[std::make_tuple(bitsize, vaddr.getIdx(), value.getIdx())];
+
+    EmitExclusiveLock(code, conf, tmp, eax);
+
+    Xbyak::Label end;
+
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorAddressPointer(conf.global_monitor, conf.processor_id)));
+    code.mov(status, u32(1));
+    code.cmp(code.byte[r15 + offsetof(A64JitState, exclusive_state)], u8(0));
+    code.je(end, code.T_NEAR);
+    code.cmp(qword[tmp], vaddr);
+    code.jne(end, code.T_NEAR);
+
+    EmitExclusiveTestAndClear(code, conf, vaddr, tmp, rax);
+
+    code.mov(code.byte[r15 + offsetof(A64JitState, exclusive_state)], u8(0));
+    code.mov(tmp, Common::BitCast<u64>(GetExclusiveMonitorValuePointer(conf.global_monitor, conf.processor_id)));
+
+    if constexpr (bitsize == 128) {
+        code.mov(rax, qword[tmp + 0]);
+        code.mov(rdx, qword[tmp + 8]);
+        if (code.HasHostFeature(HostFeature::SSE41)) {
+            code.movq(rbx, value);
+            code.pextrq(rcx, value, 1);
+        } else {
+            code.movaps(xmm0, value);
+            code.movq(rbx, xmm0);
+            code.punpckhqdq(xmm0, xmm0);
+            code.movq(rcx, xmm0);
+        }
+    } else {
+        EmitReadMemoryMov<bitsize>(code, rax.getIdx(), tmp);
+    }
+
+    const auto fastmem_marker = ShouldFastmem(ctx, inst);
+    if (fastmem_marker) {
+        Xbyak::Label abort;
+        bool require_abort_handling = false;
+
+        const auto dest_ptr = EmitFastmemVAddr(code, ctx, abort, vaddr, require_abort_handling, tmp);
+
+        const auto location = code.getCurr();
+
+        if constexpr (bitsize == 128) {
+            code.lock();
+            code.cmpxchg16b(ptr[dest_ptr]);
+        } else {
+            switch (bitsize) {
+            case 8:
+                code.lock();
+                code.cmpxchg(code.byte[dest_ptr], value.cvt8());
+                break;
+            case 16:
+                code.lock();
+                code.cmpxchg(word[dest_ptr], value.cvt16());
+                break;
+            case 32:
+                code.lock();
+                code.cmpxchg(dword[dest_ptr], value.cvt32());
+                break;
+            case 64:
+                code.lock();
+                code.cmpxchg(qword[dest_ptr], value.cvt64());
+                break;
+            default:
+                UNREACHABLE();
+            }
+        }
+
+        code.setnz(status.cvt8());
+
+        code.SwitchToFarCode();
+        code.L(abort);
+        code.call(fallback_fn);
+
+        fastmem_patch_info.emplace(
+            Common::BitCast<u64>(location),
+            FastmemPatchInfo{
+                Common::BitCast<u64>(code.getCurr()),
+                Common::BitCast<u64>(fallback_fn),
+                *fastmem_marker,
+                conf.recompile_on_exclusive_fastmem_failure,
+            });
+
+        code.cmp(al, 0);
+        code.setz(status.cvt8());
+        code.movzx(status.cvt32(), status.cvt8());
+        code.jmp(end, code.T_NEAR);
+        code.SwitchToNearCode();
+    } else {
+        code.call(fallback_fn);
+        code.cmp(al, 0);
+        code.setz(status.cvt8());
+        code.movzx(status.cvt32(), status.cvt8());
+    }
+
+    code.L(end);
+
+    EmitExclusiveUnlock(code, conf, tmp, eax);
+
+    ctx.reg_alloc.DefineValue(inst, status);
+}
+
 void A64EmitX64::EmitA64ClearExclusive(A64EmitContext&, IR::Inst*) {
     code.mov(code.byte[r15 + offsetof(A64JitState, exclusive_state)], u8(0));
 }
 
 void A64EmitX64::EmitA64ExclusiveReadMemory8(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveReadMemory<8, &A64::UserCallbacks::MemoryRead8>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveReadMemoryInline<8, &A64::UserCallbacks::MemoryRead8>(ctx, inst);
+    } else {
+        EmitExclusiveReadMemory<8, &A64::UserCallbacks::MemoryRead8>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveReadMemory16(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveReadMemory<16, &A64::UserCallbacks::MemoryRead16>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveReadMemoryInline<16, &A64::UserCallbacks::MemoryRead16>(ctx, inst);
+    } else {
+        EmitExclusiveReadMemory<16, &A64::UserCallbacks::MemoryRead16>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveReadMemory32(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveReadMemory<32, &A64::UserCallbacks::MemoryRead32>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveReadMemoryInline<32, &A64::UserCallbacks::MemoryRead32>(ctx, inst);
+    } else {
+        EmitExclusiveReadMemory<32, &A64::UserCallbacks::MemoryRead32>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveReadMemory64(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveReadMemory<64, &A64::UserCallbacks::MemoryRead64>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveReadMemoryInline<64, &A64::UserCallbacks::MemoryRead64>(ctx, inst);
+    } else {
+        EmitExclusiveReadMemory<64, &A64::UserCallbacks::MemoryRead64>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveReadMemory128(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveReadMemory<128, &A64::UserCallbacks::MemoryRead128>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveReadMemoryInline<128, &A64::UserCallbacks::MemoryRead128>(ctx, inst);
+    } else {
+        EmitExclusiveReadMemory<128, &A64::UserCallbacks::MemoryRead128>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveWriteMemory8(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveWriteMemory<8, &A64::UserCallbacks::MemoryWriteExclusive8>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveWriteMemoryInline<8, &A64::UserCallbacks::MemoryWriteExclusive8>(ctx, inst);
+    } else {
+        EmitExclusiveWriteMemory<8, &A64::UserCallbacks::MemoryWriteExclusive8>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveWriteMemory16(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveWriteMemory<16, &A64::UserCallbacks::MemoryWriteExclusive16>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveWriteMemoryInline<16, &A64::UserCallbacks::MemoryWriteExclusive16>(ctx, inst);
+    } else {
+        EmitExclusiveWriteMemory<16, &A64::UserCallbacks::MemoryWriteExclusive16>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveWriteMemory32(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveWriteMemory<32, &A64::UserCallbacks::MemoryWriteExclusive32>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveWriteMemoryInline<32, &A64::UserCallbacks::MemoryWriteExclusive32>(ctx, inst);
+    } else {
+        EmitExclusiveWriteMemory<32, &A64::UserCallbacks::MemoryWriteExclusive32>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveWriteMemory64(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveWriteMemory<64, &A64::UserCallbacks::MemoryWriteExclusive64>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveWriteMemoryInline<64, &A64::UserCallbacks::MemoryWriteExclusive64>(ctx, inst);
+    } else {
+        EmitExclusiveWriteMemory<64, &A64::UserCallbacks::MemoryWriteExclusive64>(ctx, inst);
+    }
 }
 
 void A64EmitX64::EmitA64ExclusiveWriteMemory128(A64EmitContext& ctx, IR::Inst* inst) {
-    EmitExclusiveWriteMemory<128, &A64::UserCallbacks::MemoryWriteExclusive128>(ctx, inst);
+    if (conf.fastmem_exclusive_access) {
+        EmitExclusiveWriteMemoryInline<128, &A64::UserCallbacks::MemoryWriteExclusive128>(ctx, inst);
+    } else {
+        EmitExclusiveWriteMemory<128, &A64::UserCallbacks::MemoryWriteExclusive128>(ctx, inst);
+    }
 }
 
 }  // namespace Dynarmic::Backend::X64
diff --git a/src/dynarmic/backend/x64/emit_x64_memory.h b/src/dynarmic/backend/x64/emit_x64_memory.h
new file mode 100644
index 00000000..e5cf6a48
--- /dev/null
+++ b/src/dynarmic/backend/x64/emit_x64_memory.h
@@ -0,0 +1,62 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#include <xbyak/xbyak.h>
+
+#include "dynarmic/backend/x64/a64_emit_x64.h"
+#include "dynarmic/backend/x64/exclusive_monitor_friend.h"
+#include "dynarmic/common/spin_lock_x64.h"
+#include "dynarmic/interface/exclusive_monitor.h"
+
+namespace Dynarmic::Backend::X64 {
+
+namespace {
+
+using namespace Xbyak::util;
+
+template<typename UserConfig>
+void EmitExclusiveLock(BlockOfCode& code, const UserConfig& conf, Xbyak::Reg64 pointer, Xbyak::Reg32 tmp) {
+    if (conf.HasOptimization(OptimizationFlag::Unsafe_IgnoreGlobalMonitor)) {
+        return;
+    }
+
+    code.mov(pointer, Common::BitCast<u64>(GetExclusiveMonitorLockPointer(conf.global_monitor)));
+    EmitSpinLockLock(code, pointer, tmp);
+}
+
+template<typename UserConfig>
+void EmitExclusiveUnlock(BlockOfCode& code, const UserConfig& conf, Xbyak::Reg64 pointer, Xbyak::Reg32 tmp) {
+    if (conf.HasOptimization(OptimizationFlag::Unsafe_IgnoreGlobalMonitor)) {
+        return;
+    }
+
+    code.mov(pointer, Common::BitCast<u64>(GetExclusiveMonitorLockPointer(conf.global_monitor)));
+    EmitSpinLockUnlock(code, pointer, tmp);
+}
+
+template<typename UserConfig>
+void EmitExclusiveTestAndClear(BlockOfCode& code, const UserConfig& conf, Xbyak::Reg64 vaddr, Xbyak::Reg64 pointer, Xbyak::Reg64 tmp) {
+    if (conf.HasOptimization(OptimizationFlag::Unsafe_IgnoreGlobalMonitor)) {
+        return;
+    }
+
+    code.mov(tmp, 0xDEAD'DEAD'DEAD'DEAD);
+    const size_t processor_count = GetExclusiveMonitorProcessorCount(conf.global_monitor);
+    for (size_t processor_index = 0; processor_index < processor_count; processor_index++) {
+        if (processor_index == conf.processor_id) {
+            continue;
+        }
+        Xbyak::Label ok;
+        code.mov(pointer, Common::BitCast<u64>(GetExclusiveMonitorAddressPointer(conf.global_monitor, processor_index)));
+        code.cmp(qword[pointer], vaddr);
+        code.jne(ok);
+        code.mov(qword[pointer], tmp);
+        code.L(ok);
+    }
+}
+
+}  // namespace
+
+}  // namespace Dynarmic::Backend::X64
diff --git a/src/dynarmic/backend/x64/exclusive_monitor.cpp b/src/dynarmic/backend/x64/exclusive_monitor.cpp
index 0f66270f..6a323b9f 100644
--- a/src/dynarmic/backend/x64/exclusive_monitor.cpp
+++ b/src/dynarmic/backend/x64/exclusive_monitor.cpp
@@ -21,11 +21,11 @@ size_t ExclusiveMonitor::GetProcessorCount() const {
 }
 
 void ExclusiveMonitor::Lock() {
-    while (is_locked.test_and_set(std::memory_order_acquire)) {}
+    lock.Lock();
 }
 
 void ExclusiveMonitor::Unlock() {
-    is_locked.clear(std::memory_order_release);
+    lock.Unlock();
 }
 
 bool ExclusiveMonitor::CheckAndClear(size_t processor_id, VAddr address) {
diff --git a/src/dynarmic/backend/x64/exclusive_monitor_friend.h b/src/dynarmic/backend/x64/exclusive_monitor_friend.h
new file mode 100644
index 00000000..7f7fa242
--- /dev/null
+++ b/src/dynarmic/backend/x64/exclusive_monitor_friend.h
@@ -0,0 +1,28 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#pragma once
+
+#include "dynarmic/interface/exclusive_monitor.h"
+
+namespace Dynarmic {
+
+inline volatile int* GetExclusiveMonitorLockPointer(ExclusiveMonitor* monitor) {
+    return &monitor->lock.storage;
+}
+
+inline size_t GetExclusiveMonitorProcessorCount(ExclusiveMonitor* monitor) {
+    return monitor->exclusive_addresses.size();
+}
+
+inline VAddr* GetExclusiveMonitorAddressPointer(ExclusiveMonitor* monitor, size_t index) {
+    return monitor->exclusive_addresses.data() + index;
+}
+
+inline Vector* GetExclusiveMonitorValuePointer(ExclusiveMonitor* monitor, size_t index) {
+    return monitor->exclusive_values.data() + index;
+}
+
+}  // namespace Dynarmic
diff --git a/src/dynarmic/common/spin_lock.h b/src/dynarmic/common/spin_lock.h
new file mode 100644
index 00000000..a6ea9b68
--- /dev/null
+++ b/src/dynarmic/common/spin_lock.h
@@ -0,0 +1,17 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#pragma once
+
+namespace Dynarmic {
+
+struct SpinLock {
+    void Lock();
+    void Unlock();
+
+    volatile int storage;
+};
+
+}  // namespace Dynarmic
diff --git a/src/dynarmic/common/spin_lock_x64.cpp b/src/dynarmic/common/spin_lock_x64.cpp
new file mode 100644
index 00000000..0f849931
--- /dev/null
+++ b/src/dynarmic/common/spin_lock_x64.cpp
@@ -0,0 +1,70 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#include <xbyak/xbyak.h>
+
+#include "dynarmic/backend/x64/abi.h"
+#include "dynarmic/backend/x64/hostloc.h"
+#include "dynarmic/common/spin_lock.h"
+
+namespace Dynarmic {
+
+void EmitSpinLockLock(Xbyak::CodeGenerator& code, Xbyak::Reg64 ptr, Xbyak::Reg32 tmp) {
+    Xbyak::Label start, loop;
+
+    code.jmp(start);
+    code.L(loop);
+    code.pause();
+    code.L(start);
+    code.mov(tmp, 1);
+    code.lock();
+    code.xchg(code.dword[ptr], tmp);
+    code.test(tmp, tmp);
+    code.jnz(loop);
+}
+
+void EmitSpinLockUnlock(Xbyak::CodeGenerator& code, Xbyak::Reg64 ptr, Xbyak::Reg32 tmp) {
+    code.xor_(tmp, tmp);
+    code.xchg(code.dword[ptr], tmp);
+    code.mfence();
+}
+
+namespace {
+
+struct SpinLockImpl {
+    SpinLockImpl();
+
+    Xbyak::CodeGenerator code;
+    void (*lock)(volatile int*);
+    void (*unlock)(volatile int*);
+};
+
+SpinLockImpl impl;
+
+SpinLockImpl::SpinLockImpl() {
+    const Xbyak::Reg64 ABI_PARAM1 = Backend::X64::HostLocToReg64(Backend::X64::ABI_PARAM1);
+
+    code.align();
+    lock = code.getCurr<void (*)(volatile int*)>();
+    EmitSpinLockLock(code, ABI_PARAM1, code.eax);
+    code.ret();
+
+    code.align();
+    unlock = code.getCurr<void (*)(volatile int*)>();
+    EmitSpinLockUnlock(code, ABI_PARAM1, code.eax);
+    code.ret();
+}
+
+}  // namespace
+
+void SpinLock::Lock() {
+    impl.lock(&storage);
+}
+
+void SpinLock::Unlock() {
+    impl.unlock(&storage);
+}
+
+}  // namespace Dynarmic
diff --git a/src/dynarmic/common/spin_lock_x64.h b/src/dynarmic/common/spin_lock_x64.h
new file mode 100644
index 00000000..df6a3d74
--- /dev/null
+++ b/src/dynarmic/common/spin_lock_x64.h
@@ -0,0 +1,15 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#pragma once
+
+#include <xbyak/xbyak.h>
+
+namespace Dynarmic {
+
+void EmitSpinLockLock(Xbyak::CodeGenerator& code, Xbyak::Reg64 ptr, Xbyak::Reg32 tmp);
+void EmitSpinLockUnlock(Xbyak::CodeGenerator& code, Xbyak::Reg64 ptr, Xbyak::Reg32 tmp);
+
+}  // namespace Dynarmic
diff --git a/src/dynarmic/interface/A32/config.h b/src/dynarmic/interface/A32/config.h
index dbf64c6b..75c1ec59 100644
--- a/src/dynarmic/interface/A32/config.h
+++ b/src/dynarmic/interface/A32/config.h
@@ -177,6 +177,15 @@ struct UserConfig {
     /// accesses will hit the memory callbacks.
     bool recompile_on_fastmem_failure = true;
 
+    /// Determines if we should use the above fastmem_pointer for exclusive reads and
+    /// writes. On x64, dynarmic currently relies on x64 cmpxchg semantics which may not
+    /// provide fully accurate emulation.
+    bool fastmem_exclusive_access = false;
+    /// Determines if exclusive access instructions that pagefault should cause
+    /// recompilation of that block with fastmem disabled. Recompiled code will use memory
+    /// callbacks.
+    bool recompile_on_exclusive_fastmem_failure = true;
+
     // Coprocessors
     std::array<std::shared_ptr<Coprocessor>, 16> coprocessors{};
 
diff --git a/src/dynarmic/interface/A64/config.h b/src/dynarmic/interface/A64/config.h
index 1d4a758c..7926fb5a 100644
--- a/src/dynarmic/interface/A64/config.h
+++ b/src/dynarmic/interface/A64/config.h
@@ -254,6 +254,15 @@ struct UserConfig {
     /// This is only used if fastmem_pointer is not nullptr.
     bool silently_mirror_fastmem = true;
 
+    /// Determines if we should use the above fastmem_pointer for exclusive reads and
+    /// writes. On x64, dynarmic currently relies on x64 cmpxchg semantics which may not
+    /// provide fully accurate emulation.
+    bool fastmem_exclusive_access = false;
+    /// Determines if exclusive access instructions that pagefault should cause
+    /// recompilation of that block with fastmem disabled. Recompiled code will use memory
+    /// callbacks.
+    bool recompile_on_exclusive_fastmem_failure = true;
+
     /// This option relates to translation. Generally when we run into an unpredictable
     /// instruction the ExceptionRaised callback is called. If this is true, we define
     /// definite behaviour for some unpredictable instructions.
diff --git a/src/dynarmic/interface/exclusive_monitor.h b/src/dynarmic/interface/exclusive_monitor.h
index 70b0c7f8..48136758 100644
--- a/src/dynarmic/interface/exclusive_monitor.h
+++ b/src/dynarmic/interface/exclusive_monitor.h
@@ -12,6 +12,8 @@
 #include <cstring>
 #include <vector>
 
+#include <dynarmic/common/spin_lock.h>
+
 namespace Dynarmic {
 
 using VAddr = std::uint64_t;
@@ -71,9 +73,14 @@ private:
     void Lock();
     void Unlock();
 
+    friend volatile int* GetExclusiveMonitorLockPointer(ExclusiveMonitor*);
+    friend size_t GetExclusiveMonitorProcessorCount(ExclusiveMonitor*);
+    friend VAddr* GetExclusiveMonitorAddressPointer(ExclusiveMonitor*, size_t index);
+    friend Vector* GetExclusiveMonitorValuePointer(ExclusiveMonitor*, size_t index);
+
     static constexpr VAddr RESERVATION_GRANULE_MASK = 0xFFFF'FFFF'FFFF'FFFFull;
     static constexpr VAddr INVALID_EXCLUSIVE_ADDRESS = 0xDEAD'DEAD'DEAD'DEADull;
-    std::atomic_flag is_locked;
+    SpinLock lock;
     std::vector<VAddr> exclusive_addresses;
     std::vector<Vector> exclusive_values;
 };
diff --git a/src/dynarmic/interface/optimization_flags.h b/src/dynarmic/interface/optimization_flags.h
index df7eee3e..2f65f0bf 100644
--- a/src/dynarmic/interface/optimization_flags.h
+++ b/src/dynarmic/interface/optimization_flags.h
@@ -45,6 +45,10 @@ enum class OptimizationFlag : std::uint32_t {
     /// This is an UNSAFE optimization that causes ASIMD floating-point instructions to be run with incorrect
     /// rounding modes. This may result in inaccurate results with all floating-point ASIMD instructions.
     Unsafe_IgnoreStandardFPCRValue = 0x00080000,
+    /// This is an UNSAFE optimization that causes the global monitor to be ignored. This may
+    /// result in unexpected behaviour in multithreaded scenarios, including but not limited
+    /// to data races and deadlocks.
+    Unsafe_IgnoreGlobalMonitor = 0x00100000,
 };
 
 constexpr OptimizationFlag no_optimizations = static_cast<OptimizationFlag>(0);