target/arm: Add SME enablement checks

These functions will be used to verify that the cpu
is in the correct state for a given instruction.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220708151540.18136-16-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 55 insertions, 0 deletions

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 7fab7f64f8..b16d81bf19 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -1216,6 +1216,40 @@ static bool sme_access_check(DisasContext *s)
     return true;
 }
 
+/* This function corresponds to CheckSMEEnabled. */
+bool sme_enabled_check(DisasContext *s)
+{
+    /*
+     * Note that unlike sve_excp_el, we have not constrained sme_excp_el
+     * to be zero when fp_excp_el has priority.  This is because we need
+     * sme_excp_el by itself for cpregs access checks.
+     */
+    if (!s->fp_excp_el || s->sme_excp_el < s->fp_excp_el) {
+        s->fp_access_checked = true;
+        return sme_access_check(s);
+    }
+    return fp_access_check_only(s);
+}
+
+/* Common subroutine for CheckSMEAnd*Enabled. */
+bool sme_enabled_check_with_svcr(DisasContext *s, unsigned req)
+{
+    if (!sme_enabled_check(s)) {
+        return false;
+    }
+    if (FIELD_EX64(req, SVCR, SM) && !s->pstate_sm) {
+        gen_exception_insn(s, s->pc_curr, EXCP_UDEF,
+                           syn_smetrap(SME_ET_NotStreaming, false));
+        return false;
+    }
+    if (FIELD_EX64(req, SVCR, ZA) && !s->pstate_za) {
+        gen_exception_insn(s, s->pc_curr, EXCP_UDEF,
+                           syn_smetrap(SME_ET_InactiveZA, false));
+        return false;
+    }
+    return true;
+}
+
 /*
  * This utility function is for doing register extension with an
  * optional shift. You will likely want to pass a temporary for the
diff --git a/target/arm/translate-a64.h b/target/arm/translate-a64.h
index 789b6e8e78..02fb95e019 100644
--- a/target/arm/translate-a64.h
+++ b/target/arm/translate-a64.h
@@ -29,6 +29,27 @@ void write_fp_dreg(DisasContext *s, int reg, TCGv_i64 v);
 bool logic_imm_decode_wmask(uint64_t *result, unsigned int immn,
                             unsigned int imms, unsigned int immr);
 bool sve_access_check(DisasContext *s);
+bool sme_enabled_check(DisasContext *s);
+bool sme_enabled_check_with_svcr(DisasContext *s, unsigned);
+
+/* This function corresponds to CheckStreamingSVEEnabled. */
+static inline bool sme_sm_enabled_check(DisasContext *s)
+{
+    return sme_enabled_check_with_svcr(s, R_SVCR_SM_MASK);
+}
+
+/* This function corresponds to CheckSMEAndZAEnabled. */
+static inline bool sme_za_enabled_check(DisasContext *s)
+{
+    return sme_enabled_check_with_svcr(s, R_SVCR_ZA_MASK);
+}
+
+/* Note that this function corresponds to CheckStreamingSVEAndZAEnabled. */
+static inline bool sme_smza_enabled_check(DisasContext *s)
+{
+    return sme_enabled_check_with_svcr(s, R_SVCR_SM_MASK | R_SVCR_ZA_MASK);
+}
+
 TCGv_i64 clean_data_tbi(DisasContext *s, TCGv_i64 addr);
 TCGv_i64 gen_mte_check1(DisasContext *s, TCGv_i64 addr, bool is_write,
                         bool tag_checked, int log2_size);