From 7b0143c4d7b4db4d0abe3965a4005aea661adaf2 Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Thu, 5 Jul 2012 17:31:39 +0200
Subject: [PATCH] linux-user: lock tcg

The tcg code generator is not thread safe. Lock its generation between
different threads.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 linux-user/mmap.c |    3 +++
 tcg/tcg.c         |   36 ++++++++++++++++++++++++++++++++++--
 tcg/tcg.h         |    6 ++++++
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 46523de..59718b5 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -30,6 +30,7 @@
 
 #include "qemu.h"
 #include "qemu-common.h"
+#include "tcg.h"
 
 //#define DEBUG_MMAP
 
@@ -41,6 +42,7 @@ void mmap_lock(void)
 {
     if (mmap_lock_count++ == 0) {
         pthread_mutex_lock(&mmap_mutex);
+        tcg_lock();
     }
 }
 
@@ -48,6 +50,7 @@ void mmap_unlock(void)
 {
     if (--mmap_lock_count == 0) {
         pthread_mutex_unlock(&mmap_mutex);
+        tcg_unlock();
     }
 }
 
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 8386b70..b067fc1 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -40,6 +40,8 @@
 #include "cache-utils.h"
 #include "host-utils.h"
 #include "qemu-timer.h"
+#include "config-host.h"
+#include "qemu-thread.h"
 
 /* Note: the long term plan is to reduce the dependancies on the QEMU
    CPU definitions. Currently they are used for qemu_ld/st
@@ -105,6 +107,29 @@ static TCGRegSet tcg_target_call_clobber_regs;
 uint16_t *gen_opc_ptr;
 TCGArg *gen_opparam_ptr;
 
+#ifdef CONFIG_USER_ONLY
+static __thread int tcg_lock_count;
+#endif
+void tcg_lock(void)
+{
+#ifdef CONFIG_USER_ONLY
+    TCGContext *s = &tcg_ctx;
+    if (tcg_lock_count++ == 0) {
+        qemu_mutex_lock(&s->lock);
+    }
+#endif
+}
+
+void tcg_unlock(void)
+{
+#ifdef CONFIG_USER_ONLY
+    TCGContext *s = &tcg_ctx;
+    if (--tcg_lock_count == 0) {
+        qemu_mutex_unlock(&s->lock);
+    }
+#endif
+}
+
 static inline void tcg_out8(TCGContext *s, uint8_t v)
 {
     *s->code_ptr++ = v;
@@ -245,7 +270,8 @@ void tcg_context_init(TCGContext *s)
     memset(s, 0, sizeof(*s));
     s->temps = s->static_temps;
     s->nb_globals = 0;
-    
+    qemu_mutex_init(&s->lock);
+
     /* Count total number of arguments and allocate the corresponding
        space */
     total_args = 0;
@@ -2188,11 +2214,13 @@ int tcg_gen_code(TCGContext *s, uint8_t *gen_code_buf)
     }
 #endif
 
+    tcg_lock();
     tcg_gen_code_common(s, gen_code_buf, -1);
 
     /* flush instruction cache */
     flush_icache_range((tcg_target_ulong)gen_code_buf,
                        (tcg_target_ulong)s->code_ptr);
+    tcg_unlock();
 
     return s->code_ptr -  gen_code_buf;
 }
@@ -2203,7 +2231,11 @@ int tcg_gen_code(TCGContext *s, uint8_t *gen_code_buf)
    Return -1 if not found. */
 int tcg_gen_code_search_pc(TCGContext *s, uint8_t *gen_code_buf, long offset)
 {
-    return tcg_gen_code_common(s, gen_code_buf, offset);
+    int r;
+    tcg_lock();
+    r = tcg_gen_code_common(s, gen_code_buf, offset);
+    tcg_unlock();
+    return r;
 }
 
 #ifdef CONFIG_PROFILER
diff --git a/tcg/tcg.h b/tcg/tcg.h
index d710694..9902ee6 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -46,6 +46,8 @@ typedef uint64_t tcg_target_ulong;
 #error unsupported
 #endif
 
+#include "config-host.h"
+#include "qemu-thread.h"
 #include "tcg-target.h"
 #include "tcg-runtime.h"
 
@@ -389,6 +391,7 @@ struct TCGContext {
 #ifdef CONFIG_DEBUG_TCG
     int temps_in_use;
 #endif
+    QemuMutex lock;
 };
 
 extern TCGContext tcg_ctx;
@@ -568,6 +571,9 @@ void tcg_gen_shifti_i64(TCGv_i64 ret, TCGv_i64 arg1,
 TCGArg *tcg_optimize(TCGContext *s, uint16_t *tcg_opc_ptr, TCGArg *args,
                      TCGOpDef *tcg_op_def);
 
+extern void tcg_lock(void);
+extern void tcg_unlock(void);
+
 /* only used for debugging purposes */
 void tcg_register_helper(void *func, const char *name);
 const char *tcg_helper_get_name(TCGContext *s, void *func);