From: Solomon Tan <root@wjsota.com>

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>
(cherry picked from commit 9a3bf0e0ab628de7051b41a88c4628aa9e4d311b)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 39014325df..f6e88eb5f7 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -1821,6 +1821,10 @@ 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;
-- 
2.47.2