From 2a8de5f7333de3fd50c6dddefad5123772ec550c Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Tue, 5 Jun 2018 13:05:41 +0100
Subject: [PATCH] a64_emit_x64: Clear exclusive state in EmitA64CallSupervisor

The kernel would have to execute an ERET instruction to return to
userland; this clears exclusive state.
---
 src/backend_x64/a64_emit_x64.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/backend_x64/a64_emit_x64.cpp b/src/backend_x64/a64_emit_x64.cpp
index 7079bad1..54c4163c 100644
--- a/src/backend_x64/a64_emit_x64.cpp
+++ b/src/backend_x64/a64_emit_x64.cpp
@@ -486,6 +486,8 @@ void A64EmitX64::EmitA64CallSupervisor(A64EmitContext& ctx, IR::Inst* inst) {
     DEVIRT(conf.callbacks, &A64::UserCallbacks::CallSVC).EmitCall(code, [&](RegList param) {
         code.mov(param[0], imm);
     });
+    // The kernel would have to execute ERET to get here, which would clear exclusive state.
+    code.mov(code.byte[r15 + offsetof(A64JitState, exclusive_state)], u8(0));
 }
 
 void A64EmitX64::EmitA64ExceptionRaised(A64EmitContext& ctx, IR::Inst* inst) {