[PATCH] target/riscv: Add User CSRs read-only check

[LIU Zhiwei]

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
---
 target/riscv/csr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 9a4ed18ac5..ea62d9e653 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -1422,11 +1422,11 @@ RISCVException riscv_csrrw(CPURISCVState *env, int 
csrno,
     RISCVException ret;
     target_ulong old_value;
     RISCVCPU *cpu = env_archcpu(env);
+    int read_only = get_field(csrno, 0xC00) == 3;
 
     /* check privileges and return -1 if check fails */
 #if !defined(CONFIG_USER_ONLY)
     int effective_priv = env->priv;
-    int read_only = get_field(csrno, 0xC00) == 3;
 
     if (riscv_has_ext(env, RVH) &&
         env->priv == PRV_S &&
@@ -1443,6 +1443,10 @@ RISCVException riscv_csrrw(CPURISCVState *env, int csrno,
         (!env->debugger && (effective_priv < get_field(csrno, 0x300)))) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
+#else
+    if (write_mask && read_only) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
 #endif
 
     /* ensure the CSR extension is enabled. */
-- 
2.17.1