target/riscv: Add sscofpmf extension support

The Sscofpmf ('Ss' for Privileged arch and Supervisor-level extensions,
and 'cofpmf' for Count OverFlow and Privilege Mode Filtering)
extension allows the perf to handle overflow interrupts and filtering
support. This patch provides a framework for programmable
counters to leverage the extension. As the extension doesn't have any
provision for the overflow bit for fixed counters, the fixed events
can also be monitoring using programmable counters. The underlying
counters for cycle and instruction counters are always running. Thus,
a separate timer device is programmed to handle the overflow.

Tested-by: Heiko Stuebner <heiko@sntech.de>
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: <20220824221701.41932-2-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index d895a0a..06751e1 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -136,6 +136,8 @@ typedef struct PMUCTRState {
     /* Snapshort value of a counter in RV32 */
     target_ulong mhpmcounterh_prev;
     bool started;
+    /* Value beyond UINT32_MAX/UINT64_MAX before overflow interrupt trigger */
+    target_ulong irq_overflow_left;
 } PMUCTRState;
 
 struct CPUArchState {
@@ -301,6 +303,9 @@ struct CPUArchState {
     /* PMU event selector configured values. First three are unused*/
     target_ulong mhpmevent_val[RV_MAX_MHPMEVENTS];
 
+    /* PMU event selector configured values for RV32*/
+    target_ulong mhpmeventh_val[RV_MAX_MHPMEVENTS];
+
     target_ulong sscratch;
     target_ulong mscratch;
 
@@ -447,6 +452,7 @@ struct RISCVCPUConfig {
     bool ext_zmmul;
     bool ext_smaia;
     bool ext_ssaia;
+    bool ext_sscofpmf;
     bool rvv_ta_all_1s;
     bool rvv_ma_all_1s;
 
@@ -493,6 +499,12 @@ struct ArchCPU {
 
     /* Configuration Settings */
     RISCVCPUConfig cfg;
+
+    QEMUTimer *pmu_timer;
+    /* A bitmask of Available programmable counters */
+    uint32_t pmu_avail_ctrs;
+    /* Mapping of events to counters */
+    GHashTable *pmu_event_ctr_map;
 };
 
 static inline int riscv_has_ext(CPURISCVState *env, target_ulong ext)
@@ -753,6 +765,19 @@ enum {
     CSR_TABLE_SIZE = 0x1000
 };
 
+/**
+ * The event id are encoded based on the encoding specified in the
+ * SBI specification v0.3
+ */
+
+enum riscv_pmu_event_idx {
+    RISCV_PMU_EVENT_HW_CPU_CYCLES = 0x01,
+    RISCV_PMU_EVENT_HW_INSTRUCTIONS = 0x02,
+    RISCV_PMU_EVENT_CACHE_DTLB_READ_MISS = 0x10019,
+    RISCV_PMU_EVENT_CACHE_DTLB_WRITE_MISS = 0x1001B,
+    RISCV_PMU_EVENT_CACHE_ITLB_PREFETCH_MISS = 0x10021,
+};
+
 /* CSR function table */
 extern riscv_csr_operations csr_ops[CSR_TABLE_SIZE];