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qemu-e2k/target/riscv/pmu.c
Atish Patra abd9a20665 hw/riscv: virt: Add PMU DT node to the device tree 
Qemu virt machine can support few cache events and cycle/instret counters.
It also supports counter overflow for these events.

Add a DT node so that OpenSBI/Linux kernel is aware of the virt machine
capabilities. There are some dummy nodes added for testing as well.

Acked-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: <20220824221701.41932-5-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2022-09-07 09:19:15 +02:00

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/*
* RISC-V PMU file.
*
* Copyright (c) 2021 Western Digital Corporation or its affiliates.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2 or later, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "pmu.h"
#include "sysemu/cpu-timers.h"
#include "sysemu/device_tree.h"
#define RISCV_TIMEBASE_FREQ 1000000000 /* 1Ghz */
#define MAKE_32BIT_MASK(shift, length) \
(((uint32_t)(~0UL) >> (32 - (length))) << (shift))
/*
* To keep it simple, any event can be mapped to any programmable counters in
* QEMU. The generic cycle & instruction count events can also be monitored
* using programmable counters. In that case, mcycle & minstret must continue
* to provide the correct value as well. Heterogeneous PMU per hart is not
* supported yet. Thus, number of counters are same across all harts.
*/
void riscv_pmu_generate_fdt_node(void *fdt, int num_ctrs, char *pmu_name)
{
uint32_t fdt_event_ctr_map[20] = {};
uint32_t cmask;
/* All the programmable counters can map to any event */
cmask = MAKE_32BIT_MASK(3, num_ctrs);
/*
* The event encoding is specified in the SBI specification
* Event idx is a 20bits wide number encoded as follows:
* event_idx[19:16] = type
* event_idx[15:0] = code
* The code field in cache events are encoded as follows:
* event_idx.code[15:3] = cache_id
* event_idx.code[2:1] = op_id
* event_idx.code[0:0] = result_id
*/
/* SBI_PMU_HW_CPU_CYCLES: 0x01 : type(0x00) */
fdt_event_ctr_map[0] = cpu_to_be32(0x00000001);
fdt_event_ctr_map[1] = cpu_to_be32(0x00000001);
fdt_event_ctr_map[2] = cpu_to_be32(cmask | 1 << 0);
/* SBI_PMU_HW_INSTRUCTIONS: 0x02 : type(0x00) */
fdt_event_ctr_map[3] = cpu_to_be32(0x00000002);
fdt_event_ctr_map[4] = cpu_to_be32(0x00000002);
fdt_event_ctr_map[5] = cpu_to_be32(cmask | 1 << 2);
/* SBI_PMU_HW_CACHE_DTLB : 0x03 READ : 0x00 MISS : 0x00 type(0x01) */
fdt_event_ctr_map[6] = cpu_to_be32(0x00010019);
fdt_event_ctr_map[7] = cpu_to_be32(0x00010019);
fdt_event_ctr_map[8] = cpu_to_be32(cmask);
/* SBI_PMU_HW_CACHE_DTLB : 0x03 WRITE : 0x01 MISS : 0x00 type(0x01) */
fdt_event_ctr_map[9] = cpu_to_be32(0x0001001B);
fdt_event_ctr_map[10] = cpu_to_be32(0x0001001B);
fdt_event_ctr_map[11] = cpu_to_be32(cmask);
/* SBI_PMU_HW_CACHE_ITLB : 0x04 READ : 0x00 MISS : 0x00 type(0x01) */
fdt_event_ctr_map[12] = cpu_to_be32(0x00010021);
fdt_event_ctr_map[13] = cpu_to_be32(0x00010021);
fdt_event_ctr_map[14] = cpu_to_be32(cmask);
/* This a OpenSBI specific DT property documented in OpenSBI docs */
qemu_fdt_setprop(fdt, pmu_name, "riscv,event-to-mhpmcounters",
fdt_event_ctr_map, sizeof(fdt_event_ctr_map));
}
static bool riscv_pmu_counter_valid(RISCVCPU *cpu, uint32_t ctr_idx)
{
if (ctr_idx < 3 || ctr_idx >= RV_MAX_MHPMCOUNTERS ||
!(cpu->pmu_avail_ctrs & BIT(ctr_idx))) {
return false;
} else {
return true;
}
}
static bool riscv_pmu_counter_enabled(RISCVCPU *cpu, uint32_t ctr_idx)
{
CPURISCVState *env = &cpu->env;
if (riscv_pmu_counter_valid(cpu, ctr_idx) &&
!get_field(env->mcountinhibit, BIT(ctr_idx))) {
return true;
} else {
return false;
}
}
static int riscv_pmu_incr_ctr_rv32(RISCVCPU *cpu, uint32_t ctr_idx)
{
CPURISCVState *env = &cpu->env;
target_ulong max_val = UINT32_MAX;
PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
bool virt_on = riscv_cpu_virt_enabled(env);
/* Privilege mode filtering */
if ((env->priv == PRV_M &&
(env->mhpmeventh_val[ctr_idx] & MHPMEVENTH_BIT_MINH)) ||
(env->priv == PRV_S && virt_on &&
(env->mhpmeventh_val[ctr_idx] & MHPMEVENTH_BIT_VSINH)) ||
(env->priv == PRV_U && virt_on &&
(env->mhpmeventh_val[ctr_idx] & MHPMEVENTH_BIT_VUINH)) ||
(env->priv == PRV_S && !virt_on &&
(env->mhpmeventh_val[ctr_idx] & MHPMEVENTH_BIT_SINH)) ||
(env->priv == PRV_U && !virt_on &&
(env->mhpmeventh_val[ctr_idx] & MHPMEVENTH_BIT_UINH))) {
return 0;
}
/* Handle the overflow scenario */
if (counter->mhpmcounter_val == max_val) {
if (counter->mhpmcounterh_val == max_val) {
counter->mhpmcounter_val = 0;
counter->mhpmcounterh_val = 0;
/* Generate interrupt only if OF bit is clear */
if (!(env->mhpmeventh_val[ctr_idx] & MHPMEVENTH_BIT_OF)) {
env->mhpmeventh_val[ctr_idx] |= MHPMEVENTH_BIT_OF;
riscv_cpu_update_mip(cpu, MIP_LCOFIP, BOOL_TO_MASK(1));
}
} else {
counter->mhpmcounterh_val++;
}
} else {
counter->mhpmcounter_val++;
}
return 0;
}
static int riscv_pmu_incr_ctr_rv64(RISCVCPU *cpu, uint32_t ctr_idx)
{
CPURISCVState *env = &cpu->env;
PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
uint64_t max_val = UINT64_MAX;
bool virt_on = riscv_cpu_virt_enabled(env);
/* Privilege mode filtering */
if ((env->priv == PRV_M &&
(env->mhpmevent_val[ctr_idx] & MHPMEVENT_BIT_MINH)) ||
(env->priv == PRV_S && virt_on &&
(env->mhpmevent_val[ctr_idx] & MHPMEVENT_BIT_VSINH)) ||
(env->priv == PRV_U && virt_on &&
(env->mhpmevent_val[ctr_idx] & MHPMEVENT_BIT_VUINH)) ||
(env->priv == PRV_S && !virt_on &&
(env->mhpmevent_val[ctr_idx] & MHPMEVENT_BIT_SINH)) ||
(env->priv == PRV_U && !virt_on &&
(env->mhpmevent_val[ctr_idx] & MHPMEVENT_BIT_UINH))) {
return 0;
}
/* Handle the overflow scenario */
if (counter->mhpmcounter_val == max_val) {
counter->mhpmcounter_val = 0;
/* Generate interrupt only if OF bit is clear */
if (!(env->mhpmevent_val[ctr_idx] & MHPMEVENT_BIT_OF)) {
env->mhpmevent_val[ctr_idx] |= MHPMEVENT_BIT_OF;
riscv_cpu_update_mip(cpu, MIP_LCOFIP, BOOL_TO_MASK(1));
}
} else {
counter->mhpmcounter_val++;
}
return 0;
}
int riscv_pmu_incr_ctr(RISCVCPU *cpu, enum riscv_pmu_event_idx event_idx)
{
uint32_t ctr_idx;
int ret;
CPURISCVState *env = &cpu->env;
gpointer value;
if (!cpu->cfg.pmu_num) {
return 0;
}
value = g_hash_table_lookup(cpu->pmu_event_ctr_map,
GUINT_TO_POINTER(event_idx));
if (!value) {
return -1;
}
ctr_idx = GPOINTER_TO_UINT(value);
if (!riscv_pmu_counter_enabled(cpu, ctr_idx) ||
get_field(env->mcountinhibit, BIT(ctr_idx))) {
return -1;
}
if (riscv_cpu_mxl(env) == MXL_RV32) {
ret = riscv_pmu_incr_ctr_rv32(cpu, ctr_idx);
} else {
ret = riscv_pmu_incr_ctr_rv64(cpu, ctr_idx);
}
return ret;
}
bool riscv_pmu_ctr_monitor_instructions(CPURISCVState *env,
uint32_t target_ctr)
{
RISCVCPU *cpu;
uint32_t event_idx;
uint32_t ctr_idx;
/* Fixed instret counter */
if (target_ctr == 2) {
return true;
}
cpu = RISCV_CPU(env_cpu(env));
if (!cpu->pmu_event_ctr_map) {
return false;
}
event_idx = RISCV_PMU_EVENT_HW_INSTRUCTIONS;
ctr_idx = GPOINTER_TO_UINT(g_hash_table_lookup(cpu->pmu_event_ctr_map,
GUINT_TO_POINTER(event_idx)));
if (!ctr_idx) {
return false;
}
return target_ctr == ctr_idx ? true : false;
}
bool riscv_pmu_ctr_monitor_cycles(CPURISCVState *env, uint32_t target_ctr)
{
RISCVCPU *cpu;
uint32_t event_idx;
uint32_t ctr_idx;
/* Fixed mcycle counter */
if (target_ctr == 0) {
return true;
}
cpu = RISCV_CPU(env_cpu(env));
if (!cpu->pmu_event_ctr_map) {
return false;
}
event_idx = RISCV_PMU_EVENT_HW_CPU_CYCLES;
ctr_idx = GPOINTER_TO_UINT(g_hash_table_lookup(cpu->pmu_event_ctr_map,
GUINT_TO_POINTER(event_idx)));
/* Counter zero is not used for event_ctr_map */
if (!ctr_idx) {
return false;
}
return (target_ctr == ctr_idx) ? true : false;
}
static gboolean pmu_remove_event_map(gpointer key, gpointer value,
gpointer udata)
{
return (GPOINTER_TO_UINT(value) == GPOINTER_TO_UINT(udata)) ? true : false;
}
static int64_t pmu_icount_ticks_to_ns(int64_t value)
{
int64_t ret = 0;
if (icount_enabled()) {
ret = icount_to_ns(value);
} else {
ret = (NANOSECONDS_PER_SECOND / RISCV_TIMEBASE_FREQ) * value;
}
return ret;
}
int riscv_pmu_update_event_map(CPURISCVState *env, uint64_t value,
uint32_t ctr_idx)
{
uint32_t event_idx;
RISCVCPU *cpu = RISCV_CPU(env_cpu(env));
if (!riscv_pmu_counter_valid(cpu, ctr_idx) || !cpu->pmu_event_ctr_map) {
return -1;
}
/*
* Expected mhpmevent value is zero for reset case. Remove the current
* mapping.
*/
if (!value) {
g_hash_table_foreach_remove(cpu->pmu_event_ctr_map,
pmu_remove_event_map,
GUINT_TO_POINTER(ctr_idx));
return 0;
}
event_idx = value & MHPMEVENT_IDX_MASK;
if (g_hash_table_lookup(cpu->pmu_event_ctr_map,
GUINT_TO_POINTER(event_idx))) {
return 0;
}
switch (event_idx) {
case RISCV_PMU_EVENT_HW_CPU_CYCLES:
case RISCV_PMU_EVENT_HW_INSTRUCTIONS:
case RISCV_PMU_EVENT_CACHE_DTLB_READ_MISS:
case RISCV_PMU_EVENT_CACHE_DTLB_WRITE_MISS:
case RISCV_PMU_EVENT_CACHE_ITLB_PREFETCH_MISS:
break;
default:
/* We don't support any raw events right now */
return -1;
}
g_hash_table_insert(cpu->pmu_event_ctr_map, GUINT_TO_POINTER(event_idx),
GUINT_TO_POINTER(ctr_idx));
return 0;
}
static void pmu_timer_trigger_irq(RISCVCPU *cpu,
enum riscv_pmu_event_idx evt_idx)
{
uint32_t ctr_idx;
CPURISCVState *env = &cpu->env;
PMUCTRState *counter;
target_ulong *mhpmevent_val;
uint64_t of_bit_mask;
int64_t irq_trigger_at;
if (evt_idx != RISCV_PMU_EVENT_HW_CPU_CYCLES &&
evt_idx != RISCV_PMU_EVENT_HW_INSTRUCTIONS) {
return;
}
ctr_idx = GPOINTER_TO_UINT(g_hash_table_lookup(cpu->pmu_event_ctr_map,
GUINT_TO_POINTER(evt_idx)));
if (!riscv_pmu_counter_enabled(cpu, ctr_idx)) {
return;
}
if (riscv_cpu_mxl(env) == MXL_RV32) {
mhpmevent_val = &env->mhpmeventh_val[ctr_idx];
of_bit_mask = MHPMEVENTH_BIT_OF;
} else {
mhpmevent_val = &env->mhpmevent_val[ctr_idx];
of_bit_mask = MHPMEVENT_BIT_OF;
}
counter = &env->pmu_ctrs[ctr_idx];
if (counter->irq_overflow_left > 0) {
irq_trigger_at = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
counter->irq_overflow_left;
timer_mod_anticipate_ns(cpu->pmu_timer, irq_trigger_at);
counter->irq_overflow_left = 0;
return;
}
if (cpu->pmu_avail_ctrs & BIT(ctr_idx)) {
/* Generate interrupt only if OF bit is clear */
if (!(*mhpmevent_val & of_bit_mask)) {
*mhpmevent_val |= of_bit_mask;
riscv_cpu_update_mip(cpu, MIP_LCOFIP, BOOL_TO_MASK(1));
}
}
}
/* Timer callback for instret and cycle counter overflow */
void riscv_pmu_timer_cb(void *priv)
{
RISCVCPU *cpu = priv;
/* Timer event was triggered only for these events */
pmu_timer_trigger_irq(cpu, RISCV_PMU_EVENT_HW_CPU_CYCLES);
pmu_timer_trigger_irq(cpu, RISCV_PMU_EVENT_HW_INSTRUCTIONS);
}
int riscv_pmu_setup_timer(CPURISCVState *env, uint64_t value, uint32_t ctr_idx)
{
uint64_t overflow_delta, overflow_at;
int64_t overflow_ns, overflow_left = 0;
RISCVCPU *cpu = RISCV_CPU(env_cpu(env));
PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
if (!riscv_pmu_counter_valid(cpu, ctr_idx) || !cpu->cfg.ext_sscofpmf) {
return -1;
}
if (value) {
overflow_delta = UINT64_MAX - value + 1;
} else {
overflow_delta = UINT64_MAX;
}
/*
* QEMU supports only int64_t timers while RISC-V counters are uint64_t.
* Compute the leftover and save it so that it can be reprogrammed again
* when timer expires.
*/
if (overflow_delta > INT64_MAX) {
overflow_left = overflow_delta - INT64_MAX;
}
if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
overflow_ns = pmu_icount_ticks_to_ns((int64_t)overflow_delta);
overflow_left = pmu_icount_ticks_to_ns(overflow_left) ;
} else {
return -1;
}
overflow_at = (uint64_t)qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + overflow_ns;
if (overflow_at > INT64_MAX) {
overflow_left += overflow_at - INT64_MAX;
counter->irq_overflow_left = overflow_left;
overflow_at = INT64_MAX;
}
timer_mod_anticipate_ns(cpu->pmu_timer, overflow_at);
return 0;
}
int riscv_pmu_init(RISCVCPU *cpu, int num_counters)
{
if (num_counters > (RV_MAX_MHPMCOUNTERS - 3)) {
return -1;
}
cpu->pmu_event_ctr_map = g_hash_table_new(g_direct_hash, g_direct_equal);
if (!cpu->pmu_event_ctr_map) {
/* PMU support can not be enabled */
qemu_log_mask(LOG_UNIMP, "PMU events can't be supported\n");
cpu->cfg.pmu_num = 0;
return -1;
}
/* Create a bitmask of available programmable counters */
cpu->pmu_avail_ctrs = MAKE_32BIT_MASK(3, num_counters);
return 0;
}
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