target/arm: Make RETA[AB] UNDEF when pauth is not implemented

According to the Arm A-profile A64 Instruction Set Architecture,
RETA[AB] should be decoded as UNDEF if the pauth feature is not
implemented.

We got this right in the initial implementation, but accidentally
dropped the feature-check when we converted these insns to
decodetree.

Cc: qemu-stable@nongnu.org
Fixes: 0ebbe9021254f ("target/arm: Convert BRA[AB]Z, BLR[AB]Z, RETA[AB] to decodetree")
Signed-off-by: Solomon Tan <root@wjsota.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250616171549.59190-1-root@wjsota.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index ac80f572a2d8743a92d28ff1e03151af5107f67c..d0719b5665f7c31a81a8a7c720ca12d9e1b0a58a 100644 (file)
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -1816,6 +1816,10 @@ static bool trans_RETA(DisasContext *s, arg_reta *a)
 {
     TCGv_i64 dst;
 
+    if (!dc_isar_feature(aa64_pauth, s)) {
+        return false;
+    }
+
     dst = auth_branch_target(s, cpu_reg(s, 30), cpu_X[31], !a->m);
     gen_a64_set_pc(s, dst);
     s->base.is_jmp = DISAS_JUMP;