From eacaf440195675bc528f4aac394da7a74a9d95eb Mon Sep 17 00:00:00 2001 From: Weiwei Li Date: Wed, 3 Aug 2022 20:36:52 +0800 Subject: [PATCH] target/riscv: Fix priority of csr related check in riscv_csrrw_check 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 Signed-off-by: Junqiang Wang Reviewed-by: Alistair Francis Message-Id: <20220803123652.3700-1-liweiwei@iscas.ac.cn> Signed-off-by: Alistair Francis --- 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, -- 2.11.0