s390x/tcg: make STFL store into the lowcore

Using virtual memory access is wrong and will soon include low-address
protection checks, which is to be bypassed for STFL.

STFL is a privileged instruction and using LowCore requires
!CONFIG_USER_ONLY, so add the ifdef and move the declaration to the
right place.

This was originally part of a bigger STFL(E) refactoring.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20170927170027.8539-4-david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

target/s390x/helper.h

@@ -104,7 +104,6 @@ DEF_HELPER_FLAGS_5(calc_cc, TCG_CALL_NO_RWG_SE, i32, env, i32, i64, i64, i64)
 DEF_HELPER_FLAGS_2(sfpc, TCG_CALL_NO_RWG, void, env, i64)
 DEF_HELPER_FLAGS_2(sfas, TCG_CALL_NO_WG, void, env, i64)
 DEF_HELPER_FLAGS_1(popcnt, TCG_CALL_NO_RWG_SE, i64, i64)
-DEF_HELPER_FLAGS_1(stfl, TCG_CALL_NO_RWG, void, env)
 DEF_HELPER_2(stfle, i32, env, i64)
 DEF_HELPER_FLAGS_2(lpq, TCG_CALL_NO_WG, i64, env, i64)
 DEF_HELPER_FLAGS_4(stpq, TCG_CALL_NO_WG, void, env, i64, i64, i64)
@@ -153,6 +152,7 @@ DEF_HELPER_FLAGS_3(sturg, TCG_CALL_NO_WG, void, env, i64, i64)
 DEF_HELPER_1(per_check_exception, void, env)
 DEF_HELPER_FLAGS_3(per_branch, TCG_CALL_NO_RWG, void, env, i64, i64)
 DEF_HELPER_FLAGS_2(per_ifetch, TCG_CALL_NO_RWG, void, env, i64)
+DEF_HELPER_FLAGS_1(stfl, TCG_CALL_NO_RWG, void, env)
 
 DEF_HELPER_2(xsch, void, env, i64)
 DEF_HELPER_2(csch, void, env, i64)

target/s390x/misc_helper.c

@@ -541,13 +541,18 @@ static unsigned do_stfle(CPUS390XState *env, uint64_t words[MAX_STFL_WORDS])
     return max_bit / 64;
 }
 
+#ifndef CONFIG_USER_ONLY
 void HELPER(stfl)(CPUS390XState *env)
 {
     uint64_t words[MAX_STFL_WORDS];
+    LowCore *lowcore;
 
+    lowcore = cpu_map_lowcore(env);
     do_stfle(env, words);
-    cpu_stl_data(env, 200, words[0] >> 32);
+    lowcore->stfl_fac_list = cpu_to_be32(words[0] >> 32);
+    cpu_unmap_lowcore(lowcore);
 }
+#endif
 
 uint32_t HELPER(stfle)(CPUS390XState *env, uint64_t addr)
 {