target/arm: Add cpu properties for SME

Mirror the properties for SVE.  The main difference is
that any arbitrary set of powers of 2 may be supported,
and not the stricter constraints that apply to SVE.

Include a property to control FEAT_SME_FA64, as failing
to restrict the runtime to the proper subset of insns
could be a major point for bugs.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20220620175235.60881-18-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 11 insertions, 3 deletions

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 660fd8b8b9..bb44ad45aa 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1123,11 +1123,13 @@ static void arm_cpu_initfn(Object *obj)
 #ifdef CONFIG_USER_ONLY
 # ifdef TARGET_AARCH64
     /*
-     * The linux kernel defaults to 512-bit vectors, when sve is supported.
-     * See documentation for /proc/sys/abi/sve_default_vector_length, and
-     * our corresponding sve-default-vector-length cpu property.
+     * The linux kernel defaults to 512-bit for SVE, and 256-bit for SME.
+     * These values were chosen to fit within the default signal frame.
+     * See documentation for /proc/sys/abi/{sve,sme}_default_vector_length,
+     * and our corresponding cpu property.
      */
     cpu->sve_default_vq = 4;
+    cpu->sme_default_vq = 2;
 # endif
 #else
     /* Our inbound IRQ and FIQ lines */
@@ -1430,6 +1432,12 @@ void arm_cpu_finalize_features(ARMCPU *cpu, Error **errp)
             return;
         }
 
+        arm_cpu_sme_finalize(cpu, &local_err);
+        if (local_err != NULL) {
+            error_propagate(errp, local_err);
+            return;
+        }
+
         arm_cpu_pauth_finalize(cpu, &local_err);
         if (local_err != NULL) {
             error_propagate(errp, local_err);