[PATCH 3/4] Add ePMP CSR accesses

[Hongzheng-Li <ethan.lee.qnl@gmail.com>]

From: Hou Weiying <weiying_hou@outlook.com>

Signed-off-by: Hongzheng-Li <Ethan.Lee.QNL@gmail.com>
Signed-off-by: Hou Weiying <weiying_hou@outlook.com>
Signed-off-by: Myriad-Dreamin <camiyoru@gmail.com>
---
 target/riscv/csr.c | 18 ++++++++++++++++++
 target/riscv/pmp.c | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 11d184cd16..e2395e3a51 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -112,6 +112,11 @@ static int hmode(CPURISCVState *env, int csrno)
     return -1;
 }
 
+static int epmp(CPURISCVState *env, int csrno)
+{
+    return -!(env->priv == PRV_M && riscv_feature(env, RISCV_FEATURE_EPMP));
+}
+
 static int pmp(CPURISCVState *env, int csrno)
 {
     return -!riscv_feature(env, RISCV_FEATURE_PMP);
@@ -1160,6 +1165,18 @@ static int write_pmpaddr(CPURISCVState *env, int csrno, target_ulong val)
     return 0;
 }
 
+static int read_mseccfg(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = mseccfg_csr_read(env);
+    return 0;
+}
+
+static int write_mseccfg(CPURISCVState *env, int csrno, target_ulong val)
+{
+    mseccfg_csr_write(env, val);
+    return 0;
+}
+
 #endif
 
 /*
@@ -1368,6 +1385,7 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MTINST] =              { hmode,   read_mtinst,      write_mtinst     },
 
     /* Physical Memory Protection */
+    [CSR_MSECCFG] =             { epmp,    read_mseccfg,     write_mseccfg    },
     [CSR_PMPCFG0  ... CSR_PMPADDR9] =  { pmp,   read_pmpcfg,  write_pmpcfg   },
     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
 
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 8df389cecd..0eabaf690c 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -490,3 +490,43 @@ target_ulong pmpaddr_csr_read(CPURISCVState *env, uint32_t addr_index)
 
     return val;
 }
+
+
+/*
+ * Handle a write to a mseccfg CSR
+ */
+void mseccfg_csr_write(CPURISCVState *env, target_ulong val)
+{
+    int i;
+
+    if (!MSECCFG_RLB_ISSET(env)) {
+        for (i = 0; i < MAX_RISCV_PMPS; i++) {
+            if (pmp_is_locked(env, i)) {
+                /*
+                 * Now that mseccfg.rlb is zero
+                 * the value of mseccfg.rlb should be locked.
+                 */
+                val &= ~MSECCFG_RLB;
+                break;
+            }
+        }
+    }
+
+    /*
+     * sticky bit
+     */
+    val |= (env->mseccfg & (MSECCFG_MMWP | MSECCFG_MML));
+
+    env->mseccfg = val;
+    trace_mseccfg_csr_write(env->mhartid, val);
+}
+
+
+/*
+ * Handle a read from a mseccfg CSR
+ */
+target_ulong mseccfg_csr_read(CPURISCVState *env)
+{
+    trace_mseccfg_csr_read(env->mhartid, env->mseccfg);
+    return env->mseccfg;
+}
-- 
2.20.1