tcg: Toggle page execution for Apple Silicon

Pages can't be both write and executable at the same time on Apple
Silicon. macOS provides public API to switch write protection [1] for
JIT applications, like TCG.

1. https://developer.apple.com/documentation/apple_silicon/porting_just-in-time_compilers_to_apple_silicon

Tested-by: Alexander Graf <agraf@csgraf.de>
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Message-Id: <20210113032806.18220-1-r.bolshakov@yadro.com>
[rth: Inline the qemu_thread_jit_* functions;
 drop the MAP_JIT change for a follow-on patch.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/tcg/tcg.c b/tcg/tcg.c
index 8f8badb61c..67b08f708d 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -1112,6 +1112,7 @@ void tcg_prologue_init(TCGContext *s)
     s->pool_labels = NULL;
 #endif
 
+    qemu_thread_jit_write();
     /* Generate the prologue.  */
     tcg_target_qemu_prologue(s);