[v2,16/28] linux-user: Support for restarting system calls for S390 targets

Commit Message

Peter Maydell May 12, 2016, 5:47 p.m. UTC

From: Timothy E Baldwin <[e-mail]>

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 <[e-mail]>
Message-id: [e-mail]
Reviewed-by: Peter Maydell <[e-mail]>
[PMM: tweak commit message; remove stray double semicolon; drop
 TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <[e-mail]>
---
 linux-user/main.c                | 12 +++++++++---
 linux-user/s390x/target_signal.h |  1 +
 linux-user/signal.c              |  4 ++--
 3 files changed, 12 insertions(+), 5 deletions(-)

Patch

diff --git a/linux-user/main.c b/linux-user/main.c
index c4ce071..4710e97 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3384,6 +3384,7 @@  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);
@@ -3401,9 +3402,14 @@  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 b4816b0..a6fb287 100644
--- 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 3eea6b7..51e11c1 100644
--- 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);