Re: [Qemu-devel] [Bug 1815024] [NEW] SIGILL on instruction "stck" under qemu-s390x in user mode

[Thomas Huth <thuth@redhat.com>]

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On 2019-02-07 12:05, Giovanni Mascellani wrote:
> Hi, thanks for answering!
> 
> Il 07/02/19 11:49, Cornelia Huck ha scritto:
>> Did that work before commit 7de3b1cdc67 ("s390x/tcg: properly implement
>> the TOD")?
> 
> It does not seem so
The problem is rather that the STCK instruction is fenced with
"#ifndef CONFIG_USER_ONLY" ... quick-n-dirty hack to allow it:

diff --git a/target/s390x/helper.h b/target/s390x/helper.h
index 018e9dd..8baa784 100644
--- a/target/s390x/helper.h
+++ b/target/s390x/helper.h
@@ -122,12 +122,13 @@ DEF_HELPER_4(cu42, i32, env, i32, i32, i32)
 DEF_HELPER_5(msa, i32, env, i32, i32, i32, i32)
 DEF_HELPER_FLAGS_1(stpt, TCG_CALL_NO_RWG, i64, env)
 
+DEF_HELPER_FLAGS_1(stck, TCG_CALL_NO_RWG_SE, i64, env)
+
 #ifndef CONFIG_USER_ONLY
 DEF_HELPER_3(servc, i32, env, i64, i64)
 DEF_HELPER_4(diag, void, env, i32, i32, i32)
 DEF_HELPER_3(load_psw, noreturn, env, i64, i64)
 DEF_HELPER_FLAGS_2(spx, TCG_CALL_NO_RWG, void, env, i64)
-DEF_HELPER_FLAGS_1(stck, TCG_CALL_NO_RWG_SE, i64, env)
 DEF_HELPER_FLAGS_2(sck, TCG_CALL_NO_RWG, i32, env, i64)
 DEF_HELPER_FLAGS_2(sckc, TCG_CALL_NO_RWG, void, env, i64)
 DEF_HELPER_FLAGS_2(sckpf, TCG_CALL_NO_RWG, void, env, i64)
diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
index dab805f..41e2911 100644
--- a/target/s390x/insn-data.def
+++ b/target/s390x/insn-data.def
@@ -962,6 +962,10 @@
     D(0xb93e, KIMD,    RRE,   MSA,  0, 0, 0, 0, msa, 0, S390_FEAT_TYPE_KIMD)
     D(0xb93f, KLMD,    RRE,   MSA,  0, 0, 0, 0, msa, 0, S390_FEAT_TYPE_KLMD)
 
+/* STORE CLOCK */
+    C(0xb205, STCK,    S,     Z,   la2, 0, new, m1_64, stck, 0)
+    C(0xb27c, STCKF,   S,     SCF, la2, 0, new, m1_64, stck, 0)
+
 #ifndef CONFIG_USER_ONLY
 /* COMPARE AND SWAP AND PURGE */
     E(0xb250, CSP,     RRE,   Z,   r1_32u, ra2, r1_P, 0, csp, 0, MO_TEUL, IF_PRIV)
@@ -1020,9 +1024,6 @@
     F(0x8000, SSM,     S,     Z,   0, m2_8u, 0, 0, ssm, 0, IF_PRIV)
 /* SIGNAL PROCESSOR */
     F(0xae00, SIGP,    RS_a,  Z,   0, a2, 0, 0, sigp, 0, IF_PRIV)
-/* STORE CLOCK */
-    C(0xb205, STCK,    S,     Z,   la2, 0, new, m1_64, stck, 0)
-    C(0xb27c, STCKF,   S,     SCF, la2, 0, new, m1_64, stck, 0)
 /* STORE CLOCK EXTENDED */
     C(0xb278, STCKE,   S,     Z,   0, a2, 0, 0, stcke, 0)
 /* STORE CLOCK COMPARATOR */
diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
index 52262f6..b9eea7f 100644
--- a/target/s390x/misc_helper.c
+++ b/target/s390x/misc_helper.c
@@ -396,6 +396,16 @@ uint32_t HELPER(sigp)(CPUS390XState *env, uint64_t order_code, uint32_t r1,
 
     return cc;
 }
+
+#else
+
+uint64_t HELPER(stck)(CPUS390XState *env)
+{
+    uint64_t ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+
+    return (ns << 9) / 125 + (((ns & 0xff80000000000000ull) / 125) << 9);
+}
+
 #endif
 
 #ifndef CONFIG_USER_ONLY
diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 639084a..177e281 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -4034,6 +4034,14 @@ static DisasJumpType op_ectg(DisasContext *s, DisasOps *o)
     return DISAS_NEXT;
 }
 
+static DisasJumpType op_stck(DisasContext *s, DisasOps *o)
+{
+    gen_helper_stck(o->out, cpu_env);
+    /* ??? We don't implement clock states.  */
+    gen_op_movi_cc(s, 0);
+    return DISAS_NEXT;
+}
+
 #ifndef CONFIG_USER_ONLY
 static DisasJumpType op_spka(DisasContext *s, DisasOps *o)
 {
@@ -4061,14 +4069,6 @@ static DisasJumpType op_stap(DisasContext *s, DisasOps *o)
     return DISAS_NEXT;
 }
 
-static DisasJumpType op_stck(DisasContext *s, DisasOps *o)
-{
-    gen_helper_stck(o->out, cpu_env);
-    /* ??? We don't implement clock states.  */
-    gen_op_movi_cc(s, 0);
-    return DISAS_NEXT;
-}
-
 static DisasJumpType op_stcke(DisasContext *s, DisasOps *o)
 {
     TCGv_i64 c1 = tcg_temp_new_i64();


... then your test program works fine without crashing.

 Thomas


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