target/arm: Add decodetree entry for DSB nXS variant

The DSB nXS variant is always both a reads and writes request type.
Ignore the domain field like we do in plain DSB and perform a full
system barrier operation.

The DSB nXS variant is part of FEAT_XS made mandatory from Armv8.7.

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241211144440.2700268-5-peter.maydell@linaro.org
[PMM: added missing "UNDEF unless feature present" check]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/tcg/a64.decode b/target/arm/tcg/a64.decode
index 7aa10f514716632aba1fafe85d2c53b16ce5acb9..8c798cde2b43d72ccb80a0aac392cabe9bc87af2 100644 (file)
--- a/target/arm/tcg/a64.decode
+++ b/target/arm/tcg/a64.decode
@@ -260,6 +260,9 @@ WFIT            1101 0101 0000 0011 0001 0000 001 rd:5
 
 CLREX           1101 0101 0000 0011 0011 ---- 010 11111
 DSB_DMB         1101 0101 0000 0011 0011 domain:2 types:2 10- 11111
+# For the DSB nXS variant, types always equals MBReqTypes_All and we ignore the
+# domain bits.
+DSB_nXS         1101 0101 0000 0011 0011 -- 10 001 11111
 ISB             1101 0101 0000 0011 0011 ---- 110 11111
 SB              1101 0101 0000 0011 0011 0000 111 11111
 

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index ecbc46ba55f89ff81b20b4de049012486ddf79c9..7c65fc3a3b13f5252373b7f6cbbb57ff2ed6d9d6 100644 (file)
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -1986,6 +1986,15 @@ static bool trans_DSB_DMB(DisasContext *s, arg_DSB_DMB *a)
     return true;
 }
 
+static bool trans_DSB_nXS(DisasContext *s, arg_DSB_nXS *a)
+{
+    if (!dc_isar_feature(aa64_xs, s)) {
+        return false;
+    }
+    tcg_gen_mb(TCG_BAR_SC | TCG_MO_ALL);
+    return true;
+}
+
 static bool trans_ISB(DisasContext *s, arg_ISB *a)
 {
     /*