From 047da861f94e1306cc1d76f3f76462e4f7ed2930 Mon Sep 17 00:00:00 2001
From: Frank Chang <frank.chang@sifive.com>
Date: Tue, 25 Jun 2024 19:46:25 +0800
Subject: [PATCH] target/riscv: Introduce extension implied rule helpers

Introduce helpers to enable the extensions based on the implied rules.
The implied extensions are enabled recursively, so we don't have to
expand all of them manually. This also eliminates the old-fashioned
ordering requirement. For example, Zvksg implies Zvks, Zvks implies
Zvksed, etc., removing the need to check the implied rules of Zvksg
before Zvks.

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Jerry Zhang Jian <jerry.zhangjian@sifive.com>
Tested-by: Max Chou <max.chou@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20240625114629.27793-3-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/tcg/tcg-cpu.c | 121 +++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index eb6f7b9d12..1a3aef5bff 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -31,11 +31,17 @@
 #include "hw/core/accel-cpu.h"
 #include "hw/core/tcg-cpu-ops.h"
 #include "tcg/tcg.h"
+#ifndef CONFIG_USER_ONLY
+#include "hw/boards.h"
+#endif
 
 /* Hash that stores user set extensions */
 static GHashTable *multi_ext_user_opts;
 static GHashTable *misa_ext_user_opts;
 
+static GHashTable *multi_ext_implied_rules;
+static GHashTable *misa_ext_implied_rules;
+
 static bool cpu_cfg_ext_is_user_set(uint32_t ext_offset)
 {
     return g_hash_table_contains(multi_ext_user_opts,
@@ -836,11 +842,117 @@ static void riscv_cpu_validate_profiles(RISCVCPU *cpu)
     }
 }
 
+static void riscv_cpu_init_implied_exts_rules(void)
+{
+    RISCVCPUImpliedExtsRule *rule;
+#ifndef CONFIG_USER_ONLY
+    MachineState *ms = MACHINE(qdev_get_machine());
+#endif
+    static bool initialized;
+    int i;
+
+    /* Implied rules only need to be initialized once. */
+    if (initialized) {
+        return;
+    }
+
+    for (i = 0; (rule = riscv_misa_ext_implied_rules[i]); i++) {
+#ifndef CONFIG_USER_ONLY
+        rule->enabled = bitmap_new(ms->smp.cpus);
+#endif
+        g_hash_table_insert(misa_ext_implied_rules,
+                            GUINT_TO_POINTER(rule->ext), (gpointer)rule);
+    }
+
+    for (i = 0; (rule = riscv_multi_ext_implied_rules[i]); i++) {
+#ifndef CONFIG_USER_ONLY
+        rule->enabled = bitmap_new(ms->smp.cpus);
+#endif
+        g_hash_table_insert(multi_ext_implied_rules,
+                            GUINT_TO_POINTER(rule->ext), (gpointer)rule);
+    }
+
+    initialized = true;
+}
+
+static void cpu_enable_implied_rule(RISCVCPU *cpu,
+                                    RISCVCPUImpliedExtsRule *rule)
+{
+    CPURISCVState *env = &cpu->env;
+    RISCVCPUImpliedExtsRule *ir;
+    bool enabled = false;
+    int i;
+
+#ifndef CONFIG_USER_ONLY
+    enabled = test_bit(cpu->env.mhartid, rule->enabled);
+#endif
+
+    if (!enabled) {
+        /* Enable the implied MISAs. */
+        if (rule->implied_misa_exts) {
+            riscv_cpu_set_misa_ext(env,
+                                   env->misa_ext | rule->implied_misa_exts);
+
+            for (i = 0; misa_bits[i] != 0; i++) {
+                if (rule->implied_misa_exts & misa_bits[i]) {
+                    ir = g_hash_table_lookup(misa_ext_implied_rules,
+                                             GUINT_TO_POINTER(misa_bits[i]));
+
+                    if (ir) {
+                        cpu_enable_implied_rule(cpu, ir);
+                    }
+                }
+            }
+        }
+
+        /* Enable the implied extensions. */
+        for (i = 0;
+             rule->implied_multi_exts[i] != RISCV_IMPLIED_EXTS_RULE_END; i++) {
+            cpu_cfg_ext_auto_update(cpu, rule->implied_multi_exts[i], true);
+
+            ir = g_hash_table_lookup(multi_ext_implied_rules,
+                                     GUINT_TO_POINTER(
+                                         rule->implied_multi_exts[i]));
+
+            if (ir) {
+                cpu_enable_implied_rule(cpu, ir);
+            }
+        }
+
+#ifndef CONFIG_USER_ONLY
+        bitmap_set(rule->enabled, cpu->env.mhartid, 1);
+#endif
+    }
+}
+
+static void riscv_cpu_enable_implied_rules(RISCVCPU *cpu)
+{
+    RISCVCPUImpliedExtsRule *rule;
+    int i;
+
+    /* Enable the implied MISAs. */
+    for (i = 0; (rule = riscv_misa_ext_implied_rules[i]); i++) {
+        if (riscv_has_ext(&cpu->env, rule->ext)) {
+            cpu_enable_implied_rule(cpu, rule);
+        }
+    }
+
+    /* Enable the implied extensions. */
+    for (i = 0; (rule = riscv_multi_ext_implied_rules[i]); i++) {
+        if (isa_ext_is_enabled(cpu, rule->ext)) {
+            cpu_enable_implied_rule(cpu, rule);
+        }
+    }
+}
+
 void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
 {
     CPURISCVState *env = &cpu->env;
     Error *local_err = NULL;
 
+    riscv_cpu_init_implied_exts_rules();
+    riscv_cpu_enable_implied_rules(cpu);
+
     riscv_cpu_validate_misa_priv(env, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
@@ -1346,6 +1458,15 @@ static void riscv_tcg_cpu_instance_init(CPUState *cs)
 
     misa_ext_user_opts = g_hash_table_new(NULL, g_direct_equal);
     multi_ext_user_opts = g_hash_table_new(NULL, g_direct_equal);
+
+    if (!misa_ext_implied_rules) {
+        misa_ext_implied_rules = g_hash_table_new(NULL, g_direct_equal);
+    }
+
+    if (!multi_ext_implied_rules) {
+        multi_ext_implied_rules = g_hash_table_new(NULL, g_direct_equal);
+    }
+
     riscv_cpu_add_user_properties(obj);
 
     if (riscv_cpu_has_max_extensions(obj)) {