target/riscv: Add ePMP CSR access functions

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>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 270762cb2507fba6a9eeb99a774cf49f7da9cc32.1618812899.git.alistair.francis@wdc.com
[ Changes by AF:
 - Rebase on master
 - Fix build errors
 - Fix some style issues
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index a3b253bb15..e35988eec2 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -420,6 +420,40 @@ target_ulong pmpaddr_csr_read(CPURISCVState *env, uint32_t addr_index)
 }
 
 /*
+ * Handle a write to a mseccfg CSR
+ */
+void mseccfg_csr_write(CPURISCVState *env, target_ulong val)
+{
+    int i;
+
+    trace_mseccfg_csr_write(env->mhartid, val);
+
+    /* RLB cannot be enabled if it's already 0 and if any regions are locked */
+    if (!MSECCFG_RLB_ISSET(env)) {
+        for (i = 0; i < MAX_RISCV_PMPS; i++) {
+            if (pmp_is_locked(env, i)) {
+                val &= ~MSECCFG_RLB;
+                break;
+            }
+        }
+    }
+
+    /* Sticky bits */
+    val |= (env->mseccfg & (MSECCFG_MMWP | MSECCFG_MML));
+
+    env->mseccfg = 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;
+}
+
+/*
  * Calculate the TLB size if the start address or the end address of
  * PMP entry is presented in thie TLB page.
  */