From: Bin Meng <bin.meng@windriver.com>

Add a config option to enable support for native M-mode debug.
This is disabled by default and can be enabled with 'debug=true'.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220421003324.1134983-3-bmeng.cn@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu.h | 4 +++-
 target/riscv/cpu.c | 5 +++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 39a9ff17d3..62e53e3653 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -79,7 +79,8 @@ enum {
     RISCV_FEATURE_PMP,
     RISCV_FEATURE_EPMP,
     RISCV_FEATURE_MISA,
-    RISCV_FEATURE_AIA
+    RISCV_FEATURE_AIA,
+    RISCV_FEATURE_DEBUG
 };
 
 /* Privileged specification version */
@@ -405,6 +406,7 @@ struct RISCVCPUConfig {
     bool pmp;
     bool epmp;
     bool aia;
+    bool debug;
     uint64_t resetvec;
 };
 
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 8919928f4f..477961b619 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -548,6 +548,10 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         riscv_set_feature(env, RISCV_FEATURE_AIA);
     }
 
+    if (cpu->cfg.debug) {
+        riscv_set_feature(env, RISCV_FEATURE_DEBUG);
+    }
+
     set_resetvec(env, cpu->cfg.resetvec);
 
     /* Validate that MISA_MXL is set properly. */
@@ -795,6 +799,7 @@ static Property riscv_cpu_properties[] = {
     DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
     DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
     DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
+    DEFINE_PROP_BOOL("debug", RISCVCPU, cfg.debug, false),
 
     DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
     DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
-- 
2.35.1