From 470f8674dfb19bc085c33dff970608e9bf492474 Mon Sep 17 00:00:00 2001
From: kd-11 <karokidii@gmail.com>
Date: Sat, 24 Aug 2024 02:09:22 +0300
Subject: [PATCH] aarch64 - Support for apple exceptions

---
 Utilities/Thread.cpp                             |  4 ++--
 rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.cpp |  7 +++++++
 rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.h   | 15 +++++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/Utilities/Thread.cpp b/Utilities/Thread.cpp
index f4591ee19b..bfceafaee1 100644
--- a/Utilities/Thread.cpp
+++ b/Utilities/Thread.cpp
@@ -1932,9 +1932,8 @@ static void signal_handler(int /*sig*/, siginfo_t* info, void* uct) noexcept
 	const bool is_writing = err & 0x2;
 #elif defined(ARCH_ARM64)
 	const bool is_executing = uptr(info->si_addr) == uptr(RIP(context));
-	const u32 insn = is_executing ? 0 : *reinterpret_cast<u32*>(RIP(context));
 
-#ifdef __linux__
+#if defined(__linux__) || defined(__APPLE__)
 	// Current CPU state decoder is reverse-engineered from the linux kernel and may not work on other platforms.
 	const auto decoded_reason = aarch64::decode_fault_reason(context);
 	const bool is_writing = (decoded_reason == aarch64::fault_reason::data_write);
@@ -1947,6 +1946,7 @@ static void signal_handler(int /*sig*/, siginfo_t* info, void* uct) noexcept
 	}
 
 #else
+	const u32 insn = is_executing ? 0 : *reinterpret_cast<u32*>(RIP(context));
 	const bool is_writing = 
 		(insn & 0xbfff0000) == 0x0c000000 ||  // STR <Wt>, [<Xn>, #<imm>] (store word with immediate offset)
 		(insn & 0xbfe00000) == 0x0c800000 ||  // STP <Wt1>, <Wt2>, [<Xn>, #<imm>] (store pair of registers with immediate offset)
diff --git a/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.cpp b/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.cpp
index 6d3004e82d..7beea61ccb 100644
--- a/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.cpp
+++ b/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.cpp
@@ -53,6 +53,13 @@ namespace aarch64
         auto esr_ctx = find_EL1_esr_context(uctx);
         return esr_ctx ? esr_ctx->esr : 0;
     }
+#elif defined(__APPLE__)
+    u64 _read_ESR_EL1(const ucontext_t* uctx)
+    {
+        // Easy to read from mcontext
+        const auto darwin_ctx = reinterpret_cast<aarch64_darwin_mcontext64*>(uctx->uc_mcontext);
+        return darwin_ctx->es.ESR;
+    }
 #else
     u64 _read_ESR_EL1(const ucontext_t*)
     {
diff --git a/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.h b/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.h
index 5cf5b9288f..eba782af6c 100644
--- a/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.h
+++ b/rpcs3/Emu/CPU/Backends/AArch64/AArch64Signal.h
@@ -8,6 +8,7 @@ namespace aarch64
     // Some renamed kernel definitions, we don't need to include kernel headers directly
 #pragma pack(push, 1)
 
+#if defined(__linux__)
     struct aarch64_cpu_ctx_block
     {
         u32 magic;
@@ -19,6 +20,20 @@ namespace aarch64
         aarch64_cpu_ctx_block head;
         u64 esr;      // Exception syndrome register
     };
+#elif defined(__APPLE__)
+    struct aarch64_exception_state
+    {
+        u64 FAR;      // Fault address reg
+        u32 ESR;      // Exception syndrome reg (ESR_EL1)
+        u32 exception_id;
+    };
+
+    struct aarch64_darwin_mcontext64
+    {
+        aarch64_exception_state es;
+        // Other states we don't care about follow this field
+    };
+#endif
 
 #pragma pack(pop)