target-s390x: basic PER event handling

This patch add basic support to generate PER exceptions. It adds two
fields to the cpu structure to record for the PER address and PER
code & ATMID values. When an exception is triggered and a PER event is
pending, the two PER values are copied to the lowcore area.

At the end of an instruction, an helper is checking for a possible
pending PER event and triggers an exception in that case. For that to
work with branches, we need to disable TB chaining when PER is
activated. Fortunately it's already in the TB flags.

Finally in case of a SERVICE CALL exception, we need to trigger the PER
exception immediately after.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 17 insertions, 1 deletions

diff --git a/target-s390x/translate.c b/target-s390x/translate.c
index df3389d4c7..2013a816dd 100644
--- a/target-s390x/translate.c
+++ b/target-s390x/translate.c
@@ -568,7 +568,8 @@ static int use_goto_tb(DisasContext *s, uint64_t dest)
     return (((dest & TARGET_PAGE_MASK) == (s->tb->pc & TARGET_PAGE_MASK)
              || (dest & TARGET_PAGE_MASK) == ((s->pc - 1) & TARGET_PAGE_MASK))
             && !s->singlestep_enabled
-            && !(s->tb->cflags & CF_LAST_IO));
+            && !(s->tb->cflags & CF_LAST_IO)
+            && !(s->tb->flags & FLAG_MASK_PER));
 }
 
 static void account_noninline_branch(DisasContext *s, int cc_op)
@@ -5234,6 +5235,21 @@ static ExitStatus translate_one(CPUS390XState *env, DisasContext *s)
         tcg_temp_free_i64(o.addr1);
     }
 
+#ifndef CONFIG_USER_ONLY
+    if (s->tb->flags & FLAG_MASK_PER) {
+        /* An exception might be triggered, save PSW if not already done.  */
+        if (ret == NO_EXIT || ret == EXIT_PC_STALE) {
+            tcg_gen_movi_i64(psw_addr, s->next_pc);
+        }
+
+        /* Save off cc.  */
+        update_cc_op(s);
+
+        /* Call the helper to check for a possible PER exception.  */
+        gen_helper_per_check_exception(cpu_env);
+    }
+#endif
+
     /* Advance to the next instruction.  */
     s->pc = s->next_pc;
     return ret;