[PATCH v4 2/4] target/riscv/pmp.c: Fix the index offset on RV64

[Zong Li <zong.li@sifive.com>]

On RV64, the reg_index is 2 (pmpcfg2 CSR) after the seventh pmp
entry, it is not 1 (pmpcfg1 CSR) like RV32. In the original
implementation, the second parameter of pmp_write_cfg is
"reg_index * sizeof(target_ulong)", and we get the the result
which is started from 16 if reg_index is 2, but we expect that
it should be started from 8. Separate the implementation for
RV32 and RV64 respectively.

Signed-off-by: Zong Li <zong.li@sifive.com>
---
 target/riscv/pmp.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 2a2b9f5363..e0161d6aab 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -310,6 +310,10 @@ void pmpcfg_csr_write(CPURISCVState *env, uint32_t reg_index,
     int i;
     uint8_t cfg_val;
 
+#if defined(TARGET_RISCV64)
+    reg_index >>= 1;
+#endif
+
     trace_pmpcfg_csr_write(env->mhartid, reg_index, val);
 
     if ((reg_index & 1) && (sizeof(target_ulong) == 8)) {
@@ -335,6 +339,10 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index)
     target_ulong cfg_val = 0;
     target_ulong val = 0;
 
+#if defined(TARGET_RISCV64)
+    reg_index >>= 1;
+#endif
+
     for (i = 0; i < sizeof(target_ulong); i++) {
         val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i);
         cfg_val |= (val << (i * 8));
-- 
2.27.0