On Wed, Aug 3, 2022 at 10:56 PM Weiwei Li <liwei...@iscas.ac.cn> wrote:
>
> Normally, riscv_csrrw_check is called when executing Zicsr instructions.
> And we can only do access control for existed CSRs. So the priority of
> CSR related check, from highest to lowest, should be as follows:
> 1) check whether Zicsr is supported: raise RISCV_EXCP_ILLEGAL_INST if not
> 2) check whether csr is existed: raise RISCV_EXCP_ILLEGAL_INST if not
> 3) do access control: raise RISCV_EXCP_ILLEGAL_INST or RISCV_EXCP_VIRT_
> INSTRUCTION_FAULT if not allowed
>
> The predicates contain parts of function of both 2) and 3), So they need
> to be placed in the middle of riscv_csrrw_check
>
> Signed-off-by: Weiwei Li <liwei...@iscas.ac.cn>
> Signed-off-by: Junqiang Wang <wangjunqi...@iscas.ac.cn>
Thanks!
Applied to riscv-to-apply.next
Alistair
> ---
> target/riscv/csr.c | 44 +++++++++++++++++++++++++-------------------
> 1 file changed, 25 insertions(+), 19 deletions(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 0fb042b2fd..d81f466c80 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3270,6 +3270,30 @@ static inline RISCVException
> riscv_csrrw_check(CPURISCVState *env,
> /* check privileges and return RISCV_EXCP_ILLEGAL_INST if check fails */
> int read_only = get_field(csrno, 0xC00) == 3;
> int csr_min_priv = csr_ops[csrno].min_priv_ver;
> +
> + /* ensure the CSR extension is enabled. */
> + if (!cpu->cfg.ext_icsr) {
> + return RISCV_EXCP_ILLEGAL_INST;
> + }
> +
> + if (env->priv_ver < csr_min_priv) {
> + return RISCV_EXCP_ILLEGAL_INST;
> + }
> +
> + /* check predicate */
> + if (!csr_ops[csrno].predicate) {
> + return RISCV_EXCP_ILLEGAL_INST;
> + }
> +
> + if (write_mask && read_only) {
> + return RISCV_EXCP_ILLEGAL_INST;
> + }
> +
> + RISCVException ret = csr_ops[csrno].predicate(env, csrno);
> + if (ret != RISCV_EXCP_NONE) {
> + return ret;
> + }
> +
> #if !defined(CONFIG_USER_ONLY)
> int csr_priv, effective_priv = env->priv;
>
> @@ -3290,25 +3314,7 @@ static inline RISCVException
> riscv_csrrw_check(CPURISCVState *env,
> 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) {
> - return RISCV_EXCP_ILLEGAL_INST;
> - }
> -
> - /* check predicate */
> - if (!csr_ops[csrno].predicate) {
> - return RISCV_EXCP_ILLEGAL_INST;
> - }
> -
> - if (env->priv_ver < csr_min_priv) {
> - return RISCV_EXCP_ILLEGAL_INST;
> - }
> -
> - return csr_ops[csrno].predicate(env, csrno);
> + return RISCV_EXCP_NONE;
> }
>
> static RISCVException riscv_csrrw_do64(CPURISCVState *env, int csrno,
> --
> 2.17.1
>
>
