diff mbox

[RFC,6/8] cpu: atomically modify cpu->exit_request

Message ID 20160919155139.28371-7-alex.bennee@linaro.org
State Superseded
Headers show

Commit Message

Alex Bennée Sept. 19, 2016, 3:51 p.m. UTC 
ThreadSanitizer picks up potential races although we already use
barriers to ensure things are in the correct order when processing exit
requests. For now we just use the relaxed atomic_set/atomic_read semantics
to reassure tsan that we can't tear the value.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
 cpu-exec.c | 8 ++++----
 qom/cpu.c  | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

-- 
2.9.3
diff mbox

Patch

diff --git a/cpu-exec.c b/cpu-exec.c
index 9f4bd0b..113d8dc 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -192,7 +192,7 @@  static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb)
         /* We were asked to stop executing TBs (probably a pending
          * interrupt. We've now stopped, so clear the flag.
          */
-        cpu->tcg_exit_req = 0;
+        atomic_set(&cpu->tcg_exit_req, 0);
     }
     return ret;
 }
@@ -497,8 +497,8 @@  static inline void cpu_handle_interrupt(CPUState *cpu,
             *last_tb = NULL;
         }
     }
-    if (unlikely(cpu->exit_request || replay_has_interrupt())) {
-        cpu->exit_request = 0;
+    if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) {
+        atomic_set(&cpu->exit_request, 0);
         cpu->exception_index = EXCP_INTERRUPT;
         cpu_loop_exit(cpu);
     }
@@ -510,7 +510,7 @@  static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
 {
     uintptr_t ret;
 
-    if (unlikely(cpu->exit_request)) {
+    if (unlikely(atomic_read(&cpu->exit_request))) {
         return;
     }
 
diff --git a/qom/cpu.c b/qom/cpu.c
index 2553247..47b1597 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -119,10 +119,10 @@  void cpu_reset_interrupt(CPUState *cpu, int mask)
 
 void cpu_exit(CPUState *cpu)
 {
-    cpu->exit_request = 1;
+    atomic_set(&cpu->exit_request, 1);
     /* Ensure cpu_exec will see the exit request after TCG has exited.  */
     smp_wmb();
-    cpu->tcg_exit_req = 1;
+    atomic_set(&cpu->tcg_exit_req, 1);
 }
 
 int cpu_write_elf32_qemunote(WriteCoreDumpFunction f, CPUState *cpu,