Unaligned traps are optional, but required with an mmu.
Turn them on always, because the fallback behaviour undefined.

Enable alignment checks in the config file.
Unwind the guest pc properly from do_unaligned_access.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 configs/targets/nios2-softmmu.mak | 1 +
 target/nios2/helper.c             | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/configs/targets/nios2-softmmu.mak b/configs/targets/nios2-softmmu.mak
index 9a372f0717..1e93b54cd1 100644
--- a/configs/targets/nios2-softmmu.mak
+++ b/configs/targets/nios2-softmmu.mak
@@ -1 +1,2 @@
 TARGET_ARCH=nios2
+TARGET_ALIGNED_ONLY=y
diff --git a/target/nios2/helper.c b/target/nios2/helper.c
index c5a2dd65b1..2e9fea4a01 100644
--- a/target/nios2/helper.c
+++ b/target/nios2/helper.c
@@ -241,8 +241,8 @@ void nios2_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
     CPUNios2State *env = &cpu->env;
 
     env->ctrl[CR_BADADDR] = addr;
-    env->ctrl[CR_EXCEPTION] = FIELD_DP32(0, CR_EXCEPTION, CAUSE, EXCP_UNALIGN);
-    helper_raise_exception(env, EXCP_UNALIGN);
+    cs->exception_index = EXCP_UNALIGN;
+    cpu_loop_exit_restore(cs, retaddr);
 }
 
 bool nios2_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
-- 
2.34.1