Make cpu_single_env thread-local

Make cpu_single_env thread-local. This fixes a regression
in handling of multi-threaded programs in linux-user mode
(bug 823902).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[Peter Maydell: rename tls_cpu_single_env to cpu_single_env]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

cpu-all.h

diff --git a/cpu-all.h b/cpu-all.h
index 42a5fa0..5f47ab8 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -20,6 +20,7 @@
 #define CPU_ALL_H
 
 #include "qemu-common.h"
+#include "qemu-tls.h"
 #include "cpu-common.h"
 
 /* some important defines:
@@ -334,7 +335,8 @@
 void QEMU_NORETURN cpu_abort(CPUState *env, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 extern CPUState *first_cpu;
-extern CPUState *cpu_single_env;
+DECLARE_TLS(CPUState *,cpu_single_env);
+#define cpu_single_env get_tls(cpu_single_env)
 
 /* Flags for use in ENV->INTERRUPT_PENDING.
 

exec.c

diff --git a/exec.c b/exec.c
index 54ecbe7..6b92198 100644
--- a/exec.c
+++ b/exec.c
@@ -120,7 +120,7 @@
 CPUState *first_cpu;
 /* current CPU in the current thread. It is only valid inside
    cpu_exec() */
-CPUState *cpu_single_env;
+DEFINE_TLS(CPUState *,cpu_single_env);
 /* 0 = Do not count executed instructions.
    1 = Precise instruction counting.
    2 = Adaptive rate instruction counting.  */