From: Zephyr Li <[email protected]>

The Sstc predicate currently checks both ext_sstc and rdtime_fn. This
causes the gdbstub CSR XML generation to skip Sstc CSRs when rdtime_fn
has not been initialized yet, even if the CPU supports Sstc.

As a result, GDB reports $stimecmp as void with a CPU that exposes the
sstc extension.

Only use ext_sstc for the early existence check, and keep the rdtime_fn
check for non-debugger accesses.

Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3496
Signed-off-by: Zephyr Li <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Reviewed-by: Chao Liu <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Alistair Francis <[email protected]>
---
 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 d004a4bfb4..2e81221b1d 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -590,7 +590,7 @@ static RISCVException sstc(CPURISCVState *env, int csrno)
 {
     bool hmode_check = false;
 
-    if (!riscv_cpu_cfg(env)->ext_sstc || !env->rdtime_fn) {
+    if (!riscv_cpu_cfg(env)->ext_sstc) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
 
@@ -607,6 +607,10 @@ static RISCVException sstc(CPURISCVState *env, int csrno)
         return RISCV_EXCP_NONE;
     }
 
+    if (!env->rdtime_fn) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
     if (env->priv == PRV_M) {
         return RISCV_EXCP_NONE;
     }
-- 
2.54.0


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