core: arm_unicorn: Fix interpret fallback by temporarily mapping instruction page.

src/core/arm/unicorn/arm_unicorn.cpp

@@ -11,6 +11,7 @@
 #include "core/core_timing.h"
 #include "core/hle/kernel/scheduler.h"
 #include "core/hle/kernel/svc.h"
+#include "core/memory.h"
 
 namespace Core {
 
@@ -171,7 +172,17 @@ MICROPROFILE_DEFINE(ARM_Jit_Unicorn, "ARM JIT", "Unicorn", MP_RGB(255, 64, 64));
 
 void ARM_Unicorn::ExecuteInstructions(std::size_t num_instructions) {
     MICROPROFILE_SCOPE(ARM_Jit_Unicorn);
+
+    // Temporarily map the code page for Unicorn
+    u64 map_addr{GetPC() & ~Memory::PAGE_MASK};
+    std::vector<u8> page_buffer(Memory::PAGE_SIZE);
+    system.Memory().ReadBlock(map_addr, page_buffer.data(), page_buffer.size());
+
+    CHECKED(uc_mem_map_ptr(uc, map_addr, page_buffer.size(),
+                           UC_PROT_READ | UC_PROT_WRITE | UC_PROT_EXEC, page_buffer.data()));
     CHECKED(uc_emu_start(uc, GetPC(), 1ULL << 63, 0, num_instructions));
+    CHECKED(uc_mem_unmap(uc, map_addr, page_buffer.size()));
+
     system.CoreTiming().AddTicks(num_instructions);
     if (GDBStub::IsServerEnabled()) {
         if (last_bkpt_hit && last_bkpt.type == GDBStub::BreakpointType::Execute) {