[PATCH v1 4/8] target/riscv: Add ePMP CSR access functions

[Alistair Francis]

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>
Message-Id: 
<SG2PR02MB26348FDC30678B3177B5CF3893450@SG2PR02MB2634.apcprd02.prod.outlook.com>
[ Changes by AF:
 - Rebase on master
 - Fix build errors
 - Fix some style issues
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu.h        |  1 +
 target/riscv/pmp.h        | 14 ++++++++++++++
 target/riscv/csr.c        | 22 ++++++++++++++++++++++
 target/riscv/pmp.c        | 34 ++++++++++++++++++++++++++++++++++
 target/riscv/trace-events |  3 +++
 5 files changed, 74 insertions(+)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 8dcb4a4bb2..d1198c0d0d 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -231,6 +231,7 @@ struct CPURISCVState {
 
     /* physical memory protection */
     pmp_table_t pmp_state;
+    target_ulong mseccfg;
 
     /* machine specific rdtime callback */
     uint64_t (*rdtime_fn)(uint32_t);
diff --git a/target/riscv/pmp.h b/target/riscv/pmp.h
index b82a30f0d5..a9a0b363a7 100644
--- a/target/riscv/pmp.h
+++ b/target/riscv/pmp.h
@@ -36,6 +36,12 @@ typedef enum {
     PMP_AMATCH_NAPOT /* Naturally aligned power-of-two region */
 } pmp_am_t;
 
+typedef enum {
+    MSECCFG_MML  = 1 << 0,
+    MSECCFG_MMWP = 1 << 1,
+    MSECCFG_RLB  = 1 << 2
+} mseccfg_field_t;
+
 typedef struct {
     target_ulong addr_reg;
     uint8_t  cfg_reg;
@@ -55,6 +61,10 @@ typedef struct {
 void pmpcfg_csr_write(CPURISCVState *env, uint32_t reg_index,
     target_ulong val);
 target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index);
+
+void mseccfg_csr_write(CPURISCVState *env, target_ulong val);
+target_ulong mseccfg_csr_read(CPURISCVState *env);
+
 void pmpaddr_csr_write(CPURISCVState *env, uint32_t addr_index,
     target_ulong val);
 target_ulong pmpaddr_csr_read(CPURISCVState *env, uint32_t addr_index);
@@ -68,4 +78,8 @@ void pmp_update_rule_nums(CPURISCVState *env);
 uint32_t pmp_get_num_rules(CPURISCVState *env);
 int pmp_priv_to_page_prot(pmp_priv_t pmp_priv);
 
+#define MSECCFG_MML_ISSET(env) get_field(env->mseccfg, MSECCFG_MML)
+#define MSECCFG_MMWP_ISSET(env) get_field(env->mseccfg, MSECCFG_MMWP)
+#define MSECCFG_RLB_ISSET(env) get_field(env->mseccfg, MSECCFG_RLB)
+
 #endif
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index d2585395bf..78b7fb8040 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -184,6 +184,15 @@ static int hmode32(CPURISCVState *env, int csrno)
 
 }
 
+static int epmp(CPURISCVState *env, int csrno)
+{
+    if (env->priv == PRV_M && riscv_feature(env, RISCV_FEATURE_EPMP)) {
+        return 0;
+    }
+
+    return -RISCV_EXCP_ILLEGAL_INST;
+}
+
 static int pmp(CPURISCVState *env, int csrno)
 {
     return -!riscv_feature(env, RISCV_FEATURE_PMP);
@@ -1239,6 +1248,18 @@ static int write_mtinst(CPURISCVState *env, int csrno, 
target_ulong val)
 }
 
 /* Physical Memory Protection */
+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;
+}
+
 static int read_pmpcfg(CPURISCVState *env, int csrno, target_ulong *val)
 {
     *val = pmpcfg_csr_read(env, csrno - CSR_PMPCFG0);
@@ -1473,6 +1494,7 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MTINST]      = { "mtinst",      hmode,   read_mtinst,      
write_mtinst      },
 
     /* Physical Memory Protection */
+    [CSR_MSECCFG]    = { "mseccfg",  epmp, read_mseccfg, write_mseccfg },
     [CSR_PMPCFG0]    = { "pmpcfg0",   pmp, read_pmpcfg,  write_pmpcfg  },
     [CSR_PMPCFG1]    = { "pmpcfg1",   pmp, read_pmpcfg,  write_pmpcfg  },
     [CSR_PMPCFG2]    = { "pmpcfg2",   pmp, read_pmpcfg,  write_pmpcfg  },
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 6141d0f8f9..1d071b044b 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -418,6 +418,40 @@ 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;
+
+    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.
diff --git a/target/riscv/trace-events b/target/riscv/trace-events
index b7e371ee97..49ec4d3b7d 100644
--- a/target/riscv/trace-events
+++ b/target/riscv/trace-events
@@ -6,3 +6,6 @@ pmpcfg_csr_read(uint64_t mhartid, uint32_t reg_index, uint64_t 
val) "hart %" PRI
 pmpcfg_csr_write(uint64_t mhartid, uint32_t reg_index, uint64_t val) "hart %" 
PRIu64 ": write reg%" PRIu32", val: 0x%" PRIx64
 pmpaddr_csr_read(uint64_t mhartid, uint32_t addr_index, uint64_t val) "hart %" 
PRIu64 ": read addr%" PRIu32", val: 0x%" PRIx64
 pmpaddr_csr_write(uint64_t mhartid, uint32_t addr_index, uint64_t val) "hart 
%" PRIu64 ": write addr%" PRIu32", val: 0x%" PRIx64
+
+mseccfg_csr_read(uint64_t mhartid, uint64_t val) "hart %" PRIu64 ": read 
mseccfg, val: 0x%" PRIx64
+mseccfg_csr_write(uint64_t mhartid, uint64_t val) "hart %" PRIu64 ": write 
mseccfg, val: 0x%" PRIx64
-- 
2.31.0