tcg: comment on which functions have to be called with tb_lock held

softmmu requires more functions to be thread-safe, because translation
blocks can be invalidated from e.g. notdirty callbacks.  Probably the
same holds for user-mode emulation, it's just that no one has ever
tried to produce a coherent locking there.

This patch will guide the introduction of more tb_lock and tb_unlock
calls for system emulation.

Note that after this patch some (most) of the mentioned functions are
still called outside tb_lock/tb_unlock.  The next one will rectify this.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20161027151030.20863-7-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/tcg/tcg.h b/tcg/tcg.h
index b34b5fbc2f..dc1281fb4e 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -726,6 +726,7 @@ static inline bool tcg_op_buf_full(void)
 
 /* pool based memory allocation */
 
+/* tb_lock must be held for tcg_malloc_internal. */
 void *tcg_malloc_internal(TCGContext *s, int size);
 void tcg_pool_reset(TCGContext *s);
 
@@ -733,6 +734,7 @@ void tb_lock(void);
 void tb_unlock(void);
 void tb_lock_reset(void);
 
+/* Called with tb_lock held.  */
 static inline void *tcg_malloc(int size)
 {
     TCGContext *s = &tcg_ctx;