[PATCH v3 04/51] target/arm: Add ARM_CP_SME

[Richard Henderson <richard.henderson@linaro.org>]

This will be used for controlling access to SME cpregs.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpregs.h        |  5 +++++
 target/arm/translate-a64.c | 18 ++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/target/arm/cpregs.h b/target/arm/cpregs.h
index d9b678c2f1..d30758ee71 100644
--- a/target/arm/cpregs.h
+++ b/target/arm/cpregs.h
@@ -113,6 +113,11 @@ enum {
     ARM_CP_EL3_NO_EL2_UNDEF      = 1 << 16,
     ARM_CP_EL3_NO_EL2_KEEP       = 1 << 17,
     ARM_CP_EL3_NO_EL2_C_NZ       = 1 << 18,
+    /*
+     * Flag: Access check for this sysreg is constrained by the
+     * ARM pseudocode function CheckSMEAccess().
+     */
+    ARM_CP_SME                   = 1 << 19,
 };
 
 /*
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 9a285dd177..8f609f46b6 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -1187,6 +1187,22 @@ bool sve_access_check(DisasContext *s)
     return fp_access_check(s);
 }
 
+/*
+ * Check that SME access is enabled, raise an exception if not.
+ * Note that this function corresponds to CheckSMEAccess and is
+ * only used directly for cpregs.
+ */
+static bool sme_access_check(DisasContext *s)
+{
+    if (s->sme_excp_el) {
+        gen_exception_insn_el(s, s->pc_curr, EXCP_UDEF,
+                              syn_smetrap(SME_ET_AccessTrap, false),
+                              s->sme_excp_el);
+        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
@@ -1958,6 +1974,8 @@ static void handle_sys(DisasContext *s, uint32_t insn, bool isread,
         return;
     } else if ((ri->type & ARM_CP_SVE) && !sve_access_check(s)) {
         return;
+    } else if ((ri->type & ARM_CP_SME) && !sme_access_check(s)) {
+        return;
     }
 
     if ((tb_cflags(s->base.tb) & CF_USE_ICOUNT) && (ri->type & ARM_CP_IO)) {
-- 
2.34.1