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* [PATCH v2 1/1] target/riscv: Add User CSRs read-only check
@ 2021-08-10  1:45 ` LIU Zhiwei
  0 siblings, 0 replies; 4+ messages in thread
From: LIU Zhiwei @ 2021-08-10  1:45 UTC (permalink / raw)
  To: qemu-devel, qemu-riscv; +Cc: palmer, bin.meng, Alistair.Francis, LIU Zhiwei

For U-mode CSRs, read-only check is also needed.

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---
 target/riscv/csr.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 9a4ed18ac5..5499cae94a 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 &&
@@ -1439,11 +1439,13 @@ RISCVException riscv_csrrw(CPURISCVState *env, int csrno,
         effective_priv++;
     }
 
-    if ((write_mask && read_only) ||
-        (!env->debugger && (effective_priv < get_field(csrno, 0x300)))) {
+    if (!env->debugger && (effective_priv < get_field(csrno, 0x300))) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
 #endif
+    if (write_mask && read_only) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
 
     /* ensure the CSR extension is enabled. */
     if (!cpu->cfg.ext_icsr) {
-- 
2.17.1



^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-08-13  1:44 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-10  1:45 [PATCH v2 1/1] target/riscv: Add User CSRs read-only check LIU Zhiwei
2021-08-10  1:45 ` LIU Zhiwei
2021-08-13  1:42 ` Alistair Francis
2021-08-13  1:42   ` Alistair Francis

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