target/riscv/pmp.c: respect mseccfg.RLB for pmpaddrX changes

When the rule-lock bypass (RLB) bit is set in the mseccfg CSR, the PMP
configuration lock bits must not apply. While this behavior is
implemented for the pmpcfgX CSRs, this bit is not respected for
changes to the pmpaddrX CSRs. This patch ensures that pmpaddrX CSR
writes work even on locked regions when the global rule-lock bypass is
enabled.

Signed-off-by: Leon Schuermann <leons@opentitan.org>
Reviewed-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20230829215046.1430463-1-leon@is.currently.online>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
(cherry picked from commit 4e3adce1244e1ca30ec05874c3eca14911dc0825)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index a08cd9565847e69cf5694c6bc42b95248137f40b..bcb4baa0a22f6cc0f74e347a478201e460892eaf 100644 (file)
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -45,6 +45,10 @@ static inline uint8_t pmp_get_a_field(uint8_t cfg)
  */
 static inline int pmp_is_locked(CPURISCVState *env, uint32_t pmp_index)
 {
+    /* mseccfg.RLB is set */
+    if (MSECCFG_RLB_ISSET(env)) {
+        return 0;
+    }
 
     if (env->pmp_state.pmp[pmp_index].cfg_reg & PMP_LOCK) {
         return 1;