From 7942593107fca74b66183414516e7444d78b2785 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
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The tcg code generator is not thread safe. Lock its generation between
different threads.

Signed-off-by: Alexander Graf <agraf@suse.de>
[AF: Rebased onto exec.c/translate-all.c split for 1.4]
[AF: Rebased for v2.1.0-rc0]
[AF: Rebased onto tcg_gen_code_common() drop for v2.5.0-rc0]
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 linux-user/mmap.c |  3 +++
 tcg/tcg.c         | 31 ++++++++++++++++++++++++++++++-
 tcg/tcg.h         |  6 ++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 671889b00f..b85905c0c1 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -23,6 +23,7 @@
 
 #include "qemu.h"
 #include "qemu-common.h"
+#include "tcg.h"
 #include "translate-all.h"
 
 //#define DEBUG_MMAP
@@ -34,6 +35,7 @@ void mmap_lock(void)
 {
     if (mmap_lock_count++ == 0) {
         pthread_mutex_lock(&mmap_mutex);
+        tcg_lock();
     }
 }
 
@@ -41,6 +43,7 @@ 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 796addd1fc..8c511bf2cb 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -34,6 +34,8 @@
 #include "qemu/cutils.h"
 #include "qemu/host-utils.h"
 #include "qemu/timer.h"
+#include "config-host.h"
+#include "qemu/thread.h"
 
 /* Note: the long term plan is to reduce the dependencies on the QEMU
    CPU definitions. Currently they are used for qemu_ld/st
@@ -114,6 +116,29 @@ static bool tcg_out_tb_finalize(TCGContext *s);
 static TCGRegSet tcg_target_available_regs[2];
 static TCGRegSet tcg_target_call_clobber_regs;
 
+#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
+}
+
 #if TCG_TARGET_INSN_UNIT_SIZE == 1
 static __attribute__((unused)) inline void tcg_out8(TCGContext *s, uint8_t v)
 {
@@ -326,7 +351,8 @@ void tcg_context_init(TCGContext *s)
 
     memset(s, 0, sizeof(*s));
     s->nb_globals = 0;
-    
+    qemu_mutex_init(&s->lock);
+
     /* Count total number of arguments and allocate the corresponding
        space */
     total_args = 0;
@@ -2353,6 +2379,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
         qemu_log("\n");
     }
 #endif
+    tcg_lock();
 
 #ifdef CONFIG_PROFILER
     s->opt_time -= profile_getclock();
@@ -2457,6 +2484,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
            the buffer completely.  Thus we can test for overflow after
            generating code without having to check during generation.  */
         if (unlikely((void *)s->code_ptr > s->code_gen_highwater)) {
+            tcg_unlock();
             return -1;
         }
     }
@@ -2470,6 +2498,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
 
     /* flush instruction cache */
     flush_icache_range((uintptr_t)s->code_buf, (uintptr_t)s->code_ptr);
+    tcg_unlock();
 
     return tcg_current_code_size(s);
 }
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 40c8fbe2ae..6b826af200 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -27,6 +27,7 @@
 
 #include "qemu-common.h"
 #include "qemu/bitops.h"
+#include "qemu/thread.h"
 #include "tcg-target.h"
 
 #define CPU_TEMP_BUF_NLONGS 128
@@ -591,6 +592,8 @@ struct TCGContext {
 
     uint16_t gen_insn_end_off[TCG_MAX_INSNS];
     target_ulong gen_insn_data[TCG_MAX_INSNS][TARGET_INSN_START_WORDS];
+
+    QemuMutex lock;
 };
 
 extern TCGContext tcg_ctx;
@@ -798,6 +801,9 @@ void tcg_gen_callN(TCGContext *s, void *func,
 void tcg_op_remove(TCGContext *s, TCGOp *op);
 void tcg_optimize(TCGContext *s);
 
+extern void tcg_lock(void);
+extern void tcg_unlock(void);
+
 /* only used for debugging purposes */
 void tcg_dump_ops(TCGContext *s);
 
