target/riscv: pmu: Make number of counters configurable

The RISC-V privilege specification provides flexibility to implement
any number of counters from 29 programmable counters. However, the QEMU
implements all the counters.

Make it configurable through pmu config parameter which now will indicate
how many programmable counters should be implemented by the cpu.

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-5-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

3 files changed, 63 insertions, 36 deletions

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 1b57b3c439..d12c6dc630 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -851,7 +851,6 @@ static void riscv_cpu_init(Object *obj)
 {
     RISCVCPU *cpu = RISCV_CPU(obj);
 
-    cpu->cfg.ext_pmu = true;
     cpu->cfg.ext_ifencei = true;
     cpu->cfg.ext_icsr = true;
     cpu->cfg.mmu = true;
@@ -879,7 +878,7 @@ static Property riscv_cpu_extensions[] = {
     DEFINE_PROP_BOOL("u", RISCVCPU, cfg.ext_u, true),
     DEFINE_PROP_BOOL("v", RISCVCPU, cfg.ext_v, false),
     DEFINE_PROP_BOOL("h", RISCVCPU, cfg.ext_h, true),
-    DEFINE_PROP_BOOL("pmu", RISCVCPU, cfg.ext_pmu, true),
+    DEFINE_PROP_UINT8("pmu-num", RISCVCPU, cfg.pmu_num, 16),
     DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true),
     DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true),
     DEFINE_PROP_BOOL("Zfh", RISCVCPU, cfg.ext_zfh, false),
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 252c30a55d..ffee54ea5c 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -397,7 +397,6 @@ struct RISCVCPUConfig {
     bool ext_zksed;
     bool ext_zksh;
     bool ext_zkt;
-    bool ext_pmu;
     bool ext_ifencei;
     bool ext_icsr;
     bool ext_svinval;
@@ -421,6 +420,7 @@ struct RISCVCPUConfig {
     /* Vendor-specific custom extensions */
     bool ext_XVentanaCondOps;
 
+    uint8_t pmu_num;
     char *priv_spec;
     char *user_spec;
     char *bext_spec;
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 0ca05c7788..b4a8e15f49 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -73,9 +73,17 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
     CPUState *cs = env_cpu(env);
     RISCVCPU *cpu = RISCV_CPU(cs);
     int ctr_index;
+    int base_csrno = CSR_HPMCOUNTER3;
+    bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
 
-    if (!cpu->cfg.ext_pmu) {
-        /* The PMU extension is not enabled */
+    if (rv32 && csrno >= CSR_CYCLEH) {
+        /* Offset for RV32 hpmcounternh counters */
+        base_csrno += 0x80;
+    }
+    ctr_index = csrno - base_csrno;
+
+    if (!cpu->cfg.pmu_num || ctr_index >= (cpu->cfg.pmu_num)) {
+        /* No counter is enabled in PMU or the counter is out of range */
         return RISCV_EXCP_ILLEGAL_INST;
     }
 
@@ -103,7 +111,7 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
             }
             break;
         }
-        if (riscv_cpu_mxl(env) == MXL_RV32) {
+        if (rv32) {
             switch (csrno) {
             case CSR_CYCLEH:
                 if (!get_field(env->mcounteren, COUNTEREN_CY)) {
@@ -158,7 +166,7 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
             }
             break;
         }
-        if (riscv_cpu_mxl(env) == MXL_RV32) {
+        if (rv32) {
             switch (csrno) {
             case CSR_CYCLEH:
                 if (!get_field(env->hcounteren, COUNTEREN_CY) &&
@@ -202,6 +210,26 @@ static RISCVException ctr32(CPURISCVState *env, int csrno)
 }
 
 #if !defined(CONFIG_USER_ONLY)
+static RISCVException mctr(CPURISCVState *env, int csrno)
+{
+    CPUState *cs = env_cpu(env);
+    RISCVCPU *cpu = RISCV_CPU(cs);
+    int ctr_index;
+    int base_csrno = CSR_MHPMCOUNTER3;
+
+    if ((riscv_cpu_mxl(env) == MXL_RV32) && csrno >= CSR_MCYCLEH) {
+        /* Offset for RV32 mhpmcounternh counters */
+        base_csrno += 0x80;
+    }
+    ctr_index = csrno - base_csrno;
+    if (!cpu->cfg.pmu_num || ctr_index >= cpu->cfg.pmu_num) {
+        /* The PMU is not enabled or counter is out of range*/
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    return RISCV_EXCP_NONE;
+}
+
 static RISCVException any(CPURISCVState *env, int csrno)
 {
     return RISCV_EXCP_NONE;
@@ -3687,35 +3715,35 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_HPMCOUNTER30]   = { "hpmcounter30",   ctr,    read_zero },
     [CSR_HPMCOUNTER31]   = { "hpmcounter31",   ctr,    read_zero },
 
-    [CSR_MHPMCOUNTER3]   = { "mhpmcounter3",   any,    read_zero },
-    [CSR_MHPMCOUNTER4]   = { "mhpmcounter4",   any,    read_zero },
-    [CSR_MHPMCOUNTER5]   = { "mhpmcounter5",   any,    read_zero },
-    [CSR_MHPMCOUNTER6]   = { "mhpmcounter6",   any,    read_zero },
-    [CSR_MHPMCOUNTER7]   = { "mhpmcounter7",   any,    read_zero },
-    [CSR_MHPMCOUNTER8]   = { "mhpmcounter8",   any,    read_zero },
-    [CSR_MHPMCOUNTER9]   = { "mhpmcounter9",   any,    read_zero },
-    [CSR_MHPMCOUNTER10]  = { "mhpmcounter10",  any,    read_zero },
-    [CSR_MHPMCOUNTER11]  = { "mhpmcounter11",  any,    read_zero },
-    [CSR_MHPMCOUNTER12]  = { "mhpmcounter12",  any,    read_zero },
-    [CSR_MHPMCOUNTER13]  = { "mhpmcounter13",  any,    read_zero },
-    [CSR_MHPMCOUNTER14]  = { "mhpmcounter14",  any,    read_zero },
-    [CSR_MHPMCOUNTER15]  = { "mhpmcounter15",  any,    read_zero },
-    [CSR_MHPMCOUNTER16]  = { "mhpmcounter16",  any,    read_zero },
-    [CSR_MHPMCOUNTER17]  = { "mhpmcounter17",  any,    read_zero },
-    [CSR_MHPMCOUNTER18]  = { "mhpmcounter18",  any,    read_zero },
-    [CSR_MHPMCOUNTER19]  = { "mhpmcounter19",  any,    read_zero },
-    [CSR_MHPMCOUNTER20]  = { "mhpmcounter20",  any,    read_zero },
-    [CSR_MHPMCOUNTER21]  = { "mhpmcounter21",  any,    read_zero },
-    [CSR_MHPMCOUNTER22]  = { "mhpmcounter22",  any,    read_zero },
-    [CSR_MHPMCOUNTER23]  = { "mhpmcounter23",  any,    read_zero },
-    [CSR_MHPMCOUNTER24]  = { "mhpmcounter24",  any,    read_zero },
-    [CSR_MHPMCOUNTER25]  = { "mhpmcounter25",  any,    read_zero },
-    [CSR_MHPMCOUNTER26]  = { "mhpmcounter26",  any,    read_zero },
-    [CSR_MHPMCOUNTER27]  = { "mhpmcounter27",  any,    read_zero },
-    [CSR_MHPMCOUNTER28]  = { "mhpmcounter28",  any,    read_zero },
-    [CSR_MHPMCOUNTER29]  = { "mhpmcounter29",  any,    read_zero },
-    [CSR_MHPMCOUNTER30]  = { "mhpmcounter30",  any,    read_zero },
-    [CSR_MHPMCOUNTER31]  = { "mhpmcounter31",  any,    read_zero },
+    [CSR_MHPMCOUNTER3]   = { "mhpmcounter3",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER4]   = { "mhpmcounter4",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER5]   = { "mhpmcounter5",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER6]   = { "mhpmcounter6",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER7]   = { "mhpmcounter7",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER8]   = { "mhpmcounter8",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER9]   = { "mhpmcounter9",   mctr,   read_zero },
+    [CSR_MHPMCOUNTER10]  = { "mhpmcounter10",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER11]  = { "mhpmcounter11",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER12]  = { "mhpmcounter12",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER13]  = { "mhpmcounter13",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER14]  = { "mhpmcounter14",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER15]  = { "mhpmcounter15",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER16]  = { "mhpmcounter16",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER17]  = { "mhpmcounter17",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER18]  = { "mhpmcounter18",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER19]  = { "mhpmcounter19",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER20]  = { "mhpmcounter20",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER21]  = { "mhpmcounter21",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER22]  = { "mhpmcounter22",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER23]  = { "mhpmcounter23",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER24]  = { "mhpmcounter24",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER25]  = { "mhpmcounter25",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER26]  = { "mhpmcounter26",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER27]  = { "mhpmcounter27",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER28]  = { "mhpmcounter28",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER29]  = { "mhpmcounter29",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER30]  = { "mhpmcounter30",  mctr,   read_zero },
+    [CSR_MHPMCOUNTER31]  = { "mhpmcounter31",  mctr,   read_zero },
 
     [CSR_MHPMEVENT3]     = { "mhpmevent3",     any,    read_zero },
     [CSR_MHPMEVENT4]     = { "mhpmevent4",     any,    read_zero },