linux-user: Support for restarting system calls for S390 targets

Update the S390 main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-33-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; remove stray double semicolon; 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 58dc91ced5853bc41e95c3642d5043522aa8b549..c16d7edc3a2844d9b1fab87f4bca63792999f1d5 100644 (file)
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3385,6 +3385,7 @@ void cpu_loop(CPUS390XState *env)
     int trapnr, n, sig;
     target_siginfo_t info;
     target_ulong addr;
+    abi_long ret;
 
     while (1) {
         cpu_exec_start(cs);
@@ -3402,9 +3403,14 @@ void cpu_loop(CPUS390XState *env)
                 n = env->regs[1];
             }
             env->psw.addr += env->int_svc_ilen;
-            env->regs[2] = do_syscall(env, n, env->regs[2], env->regs[3],
-                                      env->regs[4], env->regs[5],
-                                      env->regs[6], env->regs[7], 0, 0);
+            ret = do_syscall(env, n, env->regs[2], env->regs[3],
+                             env->regs[4], env->regs[5],
+                             env->regs[6], env->regs[7], 0, 0);
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->psw.addr -= env->int_svc_ilen;
+            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                env->regs[2] = ret;
+            }
             break;
 
         case EXCP_DEBUG:

diff --git a/linux-user/s390x/target_signal.h b/linux-user/s390x/target_signal.h
index b4816b040fd6233aa9b6c7b18e8932943d56b65e..a6fb2873a34ef5630963fa96b6496e3a69484ae8 100644 (file)
--- a/linux-user/s390x/target_signal.h
+++ b/linux-user/s390x/target_signal.h
@@ -23,4 +23,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUS390XState *state)
    return state->regs[15];
 }
 
+
 #endif /* TARGET_SIGNAL_H */

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 3eea6b7981fe108f5f535bed9519a6aaa39ac7ae..51e11c14fbfe807b5070f8b8edca76aea6ef916a 100644 (file)
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -4280,7 +4280,7 @@ long do_sigreturn(CPUS390XState *env)
     }
 
     unlock_user_struct(frame, frame_addr, 0);
-    return env->regs[2];
+    return -TARGET_QEMU_ESIGRETURN;
 
 badframe:
     force_sig(TARGET_SIGSEGV);
@@ -4310,7 +4310,7 @@ long do_rt_sigreturn(CPUS390XState *env)
         goto badframe;
     }
     unlock_user_struct(frame, frame_addr, 0);
-    return env->regs[2];
+    return -TARGET_QEMU_ESIGRETURN;
 
 badframe:
     unlock_user_struct(frame, frame_addr, 0);