target/sh4: Use cmpxchg for movco when parallel_cpus

As for other targets, cmpxchg isn't quite right for ll/sc,
suffering from an ABA race, but is sufficient to implement
portable atomic operations.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20170907185057.23421-2-richard.henderson@linaro.org>
[aurel32: fix whitespace]
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 15 insertions, 4 deletions

diff --git a/linux-user/main.c b/linux-user/main.c
index 2fd2a143ed..71696ed33d 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2679,6 +2679,8 @@ void cpu_loop(CPUSH4State *env)
     target_siginfo_t info;
 
     while (1) {
+        bool arch_interrupt = true;
+
         cpu_exec_start(cs);
         trapnr = cpu_exec(cs);
         cpu_exec_end(cs);
@@ -2710,13 +2712,14 @@ void cpu_loop(CPUSH4State *env)
                 int sig;
 
                 sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
+                if (sig) {
                     info.si_signo = sig;
                     info.si_errno = 0;
                     info.si_code = TARGET_TRAP_BRKPT;
                     queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
+                } else {
+                    arch_interrupt = false;
+                }
             }
             break;
 	case 0xa0:
@@ -2727,9 +2730,9 @@ void cpu_loop(CPUSH4State *env)
             info._sifields._sigfault._addr = env->tea;
             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
 	    break;
-
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);
+            arch_interrupt = false;
             break;
         default:
             printf ("Unhandled trap: 0x%x\n", trapnr);
@@ -2737,6 +2740,14 @@ void cpu_loop(CPUSH4State *env)
             exit(EXIT_FAILURE);
         }
         process_pending_signals (env);
+
+        /* Most of the traps imply an exception or interrupt, which
+           implies an REI instruction has been executed.  Which means
+           that LDST (aka LOK_ADDR) should be cleared.  But there are
+           a few exceptions for traps internal to QEMU.  */
+        if (arch_interrupt) {
+            env->lock_addr = -1;
+        }
     }
 }
 #endif