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>
[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]
[AF: Rebased for v2.7.0-rc2]
Signed-off-by: Andreas Färber <afaerber@suse.de>

3 files changed, 38 insertions, 0 deletions

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 68a655e63..d202e453f 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -22,6 +22,7 @@
 
 #include "qemu.h"
 #include "qemu-common.h"
+#include "tcg.h"
 #include "translate-all.h"
 
 //#define DEBUG_MMAP
@@ -33,6 +34,7 @@ void mmap_lock(void)
 {
     if (mmap_lock_count++ == 0) {
         pthread_mutex_lock(&mmap_mutex);
+        tcg_lock();
     }
 }
 
@@ -40,6 +42,7 @@ 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 42417bdc9..ef6ae1011 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -33,6 +33,8 @@
 #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
@@ -120,6 +122,29 @@ 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)
 {
@@ -332,6 +357,7 @@ 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 */
@@ -2551,6 +2577,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
         qemu_log("\n");
     }
 #endif
+    tcg_lock();
 
 #ifdef CONFIG_PROFILER
     s->opt_time -= profile_getclock();
@@ -2673,6 +2700,7 @@ 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;
         }
     }
@@ -2686,6 +2714,7 @@ 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 1bcabcad9..5c2522e50 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -29,6 +29,7 @@
 #include "cpu.h"
 #include "exec/tb-context.h"
 #include "qemu/bitops.h"
+#include "qemu/thread.h"
 #include "tcg-target.h"
 
 /* XXX: make safe guess about sizes */
@@ -697,6 +698,8 @@ 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;
@@ -904,6 +907,9 @@ TCGOp *tcg_op_insert_after(TCGContext *s, TCGOp *op, TCGOpcode opc, int narg);
 
 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);