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

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>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 51e11c14fb..71a8e2ac66 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);
 }