[Qemu-devel] [PATCH v2 17/28] linux-user: Support for restarting system calls for CRIS targets

[Peter Maydell <peter.maydell@linaro.org>]

From: Timothy E Baldwin <T.E.Baldwin99@members.leeds.ac.uk>

Update the CRIS 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: 1441497448-32489-34-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/cris/target_signal.h | 1 +
 linux-user/main.c               | 6 +++++-
 linux-user/signal.c             | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/linux-user/cris/target_signal.h b/linux-user/cris/target_signal.h
index 5611840..e0f1382 100644
--- a/linux-user/cris/target_signal.h
+++ b/linux-user/cris/target_signal.h
@@ -26,4 +26,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUCRISState *state)
     return state->regs[14];
 }
 
+
 #endif /* TARGET_SIGNAL_H */
diff --git a/linux-user/main.c b/linux-user/main.c
index 4710e97..2df4e27 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2913,7 +2913,11 @@ void cpu_loop(CPUCRISState *env)
                              env->pregs[7], 
                              env->pregs[11],
                              0, 0);
-            env->regs[10] = ret;
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->pc -= 2;
+            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                env->regs[10] = ret;
+            }
             break;
         case EXCP_DEBUG:
             {
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 51e11c1..71a8e2a 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -3785,7 +3785,7 @@ long do_sigreturn(CPUCRISState *env)
 
     restore_sigcontext(&frame->sc, env);
     unlock_user_struct(frame, frame_addr, 0);
-    return env->regs[10];
+    return -TARGET_QEMU_ESIGRETURN;
 badframe:
     force_sig(TARGET_SIGSEGV);
 }
-- 
1.9.1