linux-user: Support for restarting system calls for OpenRISC targets

Update the OpenRISC main loop code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

(We don't implement sigreturn on this target so there is no
code there to update.)

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-31-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

diff --git a/linux-user/main.c b/linux-user/main.c
index 9e6448af4833402fbcf227c80f5d160312f91f1c..6a0be7db1c8ab70c5742d23e2d25c1152425e6bf 100644 (file)
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2724,6 +2724,7 @@ void cpu_loop(CPUOpenRISCState *env)
 {
     CPUState *cs = CPU(openrisc_env_get_cpu(env));
     int trapnr, gdbsig;
+    abi_long ret;
 
     for (;;) {
         cpu_exec_start(cs);
@@ -2769,14 +2770,19 @@ void cpu_loop(CPUOpenRISCState *env)
             break;
         case EXCP_SYSCALL:
             env->pc += 4;   /* 0xc00; */
-            env->gpr[11] = do_syscall(env,
-                                      env->gpr[11], /* return value       */
-                                      env->gpr[3],  /* r3 - r7 are params */
-                                      env->gpr[4],
-                                      env->gpr[5],
-                                      env->gpr[6],
-                                      env->gpr[7],
-                                      env->gpr[8], 0, 0);
+            ret = do_syscall(env,
+                             env->gpr[11], /* return value       */
+                             env->gpr[3],  /* r3 - r7 are params */
+                             env->gpr[4],
+                             env->gpr[5],
+                             env->gpr[6],
+                             env->gpr[7],
+                             env->gpr[8], 0, 0);
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->pc -= 4;
+            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                env->gpr[11] = ret;
+            }
             break;
         case EXCP_FPE:
             qemu_log_mask(CPU_LOG_INT, "\nFloating point error\n");

diff --git a/linux-user/openrisc/target_signal.h b/linux-user/openrisc/target_signal.h
index 964aed69f1311d55835deb0ef4d1bdd3e02c6768..f600501f6f46fa636b280c05a0fd3ab24400b6c1 100644 (file)
--- a/linux-user/openrisc/target_signal.h
+++ b/linux-user/openrisc/target_signal.h
@@ -23,4 +23,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUOpenRISCState *state)
     return state->gpr[1];
 }
 
+
 #endif /* TARGET_SIGNAL_H */