[ PATCH v3 05/10] target/riscv: Implement mcountinhibit CSR

[Atish Patra]

As per the privilege specification v1.11, mcountinhibit allows to start/stop
a pmu counter selectively.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
 target/riscv/cpu.h      |  2 ++
 target/riscv/cpu_bits.h |  4 ++++
 target/riscv/csr.c      | 25 +++++++++++++++++++++++++
 target/riscv/machine.c  |  5 +++--
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index d0a722e7cbe1..b421eefa623f 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -217,6 +217,8 @@ struct CPURISCVState {
     target_ulong scounteren;
     target_ulong mcounteren;
 
+    target_ulong mcountinhibit;
+
     target_ulong sscratch;
     target_ulong mscratch;
 
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 999187a9ee2d..72b1485e621f 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -275,6 +275,10 @@
 #define CSR_MHPMCOUNTER29   0xb1d
 #define CSR_MHPMCOUNTER30   0xb1e
 #define CSR_MHPMCOUNTER31   0xb1f
+
+/* Machine counter-inhibit register */
+#define CSR_MCOUNTINHIBIT   0x320
+
 #define CSR_MHPMEVENT3      0x323
 #define CSR_MHPMEVENT4      0x324
 #define CSR_MHPMEVENT5      0x325
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index a7249eaf917f..faf02e12ec34 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -766,6 +766,28 @@ static RISCVException write_mtvec(CPURISCVState *env, int 
csrno,
     return RISCV_EXCP_NONE;
 }
 
+static RISCVException read_mcountinhibit(CPURISCVState *env, int csrno,
+                                         target_ulong *val)
+{
+    if (env->priv_ver < PRIV_VERSION_1_11_0) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    *val = env->mcountinhibit;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_mcountinhibit(CPURISCVState *env, int csrno,
+                                          target_ulong val)
+{
+    if (env->priv_ver < PRIV_VERSION_1_11_0) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    env->mcountinhibit = val;
+    return RISCV_EXCP_NONE;
+}
+
 static RISCVException read_mcounteren(CPURISCVState *env, int csrno,
                                       target_ulong *val)
 {
@@ -1780,6 +1802,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MHPMCOUNTER30]  = { "mhpmcounter30",  mctr,   read_zero },
     [CSR_MHPMCOUNTER31]  = { "mhpmcounter31",  mctr,   read_zero },
 
+    [CSR_MCOUNTINHIBIT]  = { "mcountinhibit",   any,    read_mcountinhibit,
+                                                       write_mcountinhibit },
+
     [CSR_MHPMEVENT3]     = { "mhpmevent3",     any,    read_zero },
     [CSR_MHPMEVENT4]     = { "mhpmevent4",     any,    read_zero },
     [CSR_MHPMEVENT5]     = { "mhpmevent5",     any,    read_zero },
diff --git a/target/riscv/machine.c b/target/riscv/machine.c
index 16a08302daff..20dea0843604 100644
--- a/target/riscv/machine.c
+++ b/target/riscv/machine.c
@@ -140,8 +140,8 @@ static const VMStateDescription vmstate_hyper = {
 
 const VMStateDescription vmstate_riscv_cpu = {
     .name = "cpu",
-    .version_id = 2,
-    .minimum_version_id = 2,
+    .version_id = 3,
+    .minimum_version_id = 3,
     .fields = (VMStateField[]) {
         VMSTATE_UINTTL_ARRAY(env.gpr, RISCVCPU, 32),
         VMSTATE_UINT64_ARRAY(env.fpr, RISCVCPU, 32),
@@ -177,6 +177,7 @@ const VMStateDescription vmstate_riscv_cpu = {
         VMSTATE_UINTTL(env.mtval, RISCVCPU),
         VMSTATE_UINTTL(env.scounteren, RISCVCPU),
         VMSTATE_UINTTL(env.mcounteren, RISCVCPU),
+        VMSTATE_UINTTL(env.mcountinhibit, RISCVCPU),
         VMSTATE_UINTTL(env.sscratch, RISCVCPU),
         VMSTATE_UINTTL(env.mscratch, RISCVCPU),
         VMSTATE_UINT64(env.mfromhost, RISCVCPU),
-- 
2.31.1