[PATCH 1/4] target/riscv: Add functions for common matching conditions of trigger

[Alvin Chang]

According to RISC-V Debug specification, there are several common
matching conditions before firing a trigger, including the enabled
privilege levels of the trigger.

This commit adds trigger_common_match() to prepare the common matching
conditions for the type 2/3/6 triggers. For now, we just implement
trigger_priv_match() to check if the enabled privilege levels of the
trigger match CPU's current privilege level.

Signed-off-by: Alvin Chang <alvinga@andestech.com>
---
 target/riscv/debug.c | 70 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/target/riscv/debug.c b/target/riscv/debug.c
index e30d99cc2f..7932233073 100644
--- a/target/riscv/debug.c
+++ b/target/riscv/debug.c
@@ -241,6 +241,76 @@ static void do_trigger_action(CPURISCVState *env, 
target_ulong trigger_index)
     }
 }
 
+/*
+ * Check the privilege level of specific trigger matches CPU's current 
privilege
+ * level.
+ */
+static bool trigger_priv_match(CPURISCVState *env, trigger_type_t type,
+                               int trigger_index)
+{
+    target_ulong ctrl = env->tdata1[trigger_index];
+
+    switch (type) {
+    case TRIGGER_TYPE_AD_MATCH:
+        /* type 2 trigger cannot be fired in VU/VS mode */
+        if (env->virt_enabled) {
+            return false;
+        }
+        /* check U/S/M bit against current privilege level */
+        if ((ctrl >> 3) & BIT(env->priv)) {
+            return true;
+        }
+        break;
+    case TRIGGER_TYPE_AD_MATCH6:
+        if (env->virt_enabled) {
+            /* check VU/VS bit against current privilege level */
+            if ((ctrl >> 23) & BIT(env->priv)) {
+                return true;
+            }
+        } else {
+            /* check U/S/M bit against current privilege level */
+            if ((ctrl >> 3) & BIT(env->priv)) {
+                return true;
+            }
+        }
+        break;
+    case TRIGGER_TYPE_INST_CNT:
+        if (env->virt_enabled) {
+            /* check VU/VS bit against current privilege level */
+            if ((ctrl >> 25) & BIT(env->priv)) {
+                return true;
+            }
+        } else {
+            /* check U/S/M bit against current privilege level */
+            if ((ctrl >> 6) & BIT(env->priv)) {
+                return true;
+            }
+        }
+        break;
+    case TRIGGER_TYPE_INT:
+    case TRIGGER_TYPE_EXCP:
+    case TRIGGER_TYPE_EXT_SRC:
+        qemu_log_mask(LOG_UNIMP, "trigger type: %d is not supported\n", type);
+        break;
+    case TRIGGER_TYPE_NO_EXIST:
+    case TRIGGER_TYPE_UNAVAIL:
+        qemu_log_mask(LOG_GUEST_ERROR, "trigger type: %d does not exit\n",
+                      type);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    return false;
+}
+
+/* Common matching conditions for all types of the triggers. */
+static bool trigger_common_match(CPURISCVState *env, trigger_type_t type,
+                                 int trigger_index)
+{
+    return trigger_priv_match(env, type, trigger_index);
+}
+
 /* type 2 trigger */
 
 static uint32_t type2_breakpoint_size(CPURISCVState *env, target_ulong ctrl)
-- 
2.34.1