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target/riscv: Support mcycle/minstret write operation 

mcycle/minstret are actually WARL registers and can be written with any
given value. With SBI PMU extension, it will be used to store a initial
value provided from supervisor OS. The Qemu also need prohibit the counter
increment if mcountinhibit is set.

Support mcycle/minstret through generic counter infrastructure.

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: <20220620231603.2547260-8-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Atish Patra 2022-06-20 16:15:57 -07:00 committed by Alistair Francis
parent 621f35bb2f
commit 3780e33732
6 changed files with 215 additions and 55 deletions
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23
target/riscv/cpu.h
View File

@ -117,7 +117,7 @@ typedef struct CPUArchState CPURISCVState;
#endif
#define RV_VLEN_MAX 1024
#define RV_MAX_MHPMEVENTS 29
#define RV_MAX_MHPMEVENTS 32
#define RV_MAX_MHPMCOUNTERS 32
FIELD(VTYPE, VLMUL, 0, 3)
@ -127,6 +127,18 @@ FIELD(VTYPE, VMA, 7, 1)
FIELD(VTYPE, VEDIV, 8, 2)
FIELD(VTYPE, RESERVED, 10, sizeof(target_ulong) * 8 - 11)
typedef struct PMUCTRState {
/* Current value of a counter */
target_ulong mhpmcounter_val;
/* Current value of a counter in RV32*/
target_ulong mhpmcounterh_val;
/* Snapshot values of counter */
target_ulong mhpmcounter_prev;
/* Snapshort value of a counter in RV32 */
target_ulong mhpmcounterh_prev;
bool started;
} PMUCTRState;
struct CPUArchState {
target_ulong gpr[32];
target_ulong gprh[32]; /* 64 top bits of the 128-bit registers */
@ -279,13 +291,10 @@ struct CPUArchState {
target_ulong mcountinhibit;
/* PMU counter configured values */
target_ulong mhpmcounter_val[RV_MAX_MHPMCOUNTERS];
/* PMU counter state */
PMUCTRState pmu_ctrs[RV_MAX_MHPMCOUNTERS];
/* for RV32 */
target_ulong mhpmcounterh_val[RV_MAX_MHPMCOUNTERS];
/* PMU event selector configured values */
/* PMU event selector configured values. First three are unused*/
target_ulong mhpmevent_val[RV_MAX_MHPMEVENTS];
target_ulong sscratch;

159
target/riscv/csr.c
View File

@ -21,6 +21,7 @@
#include "qemu/log.h"
#include "qemu/timer.h"
#include "cpu.h"
#include "pmu.h"
#include "qemu/main-loop.h"
#include "exec/exec-all.h"
#include "sysemu/cpu-timers.h"
@ -597,34 +598,28 @@ static int write_vcsr(CPURISCVState *env, int csrno, target_ulong val)
}
/* User Timers and Counters */
static RISCVException read_instret(CPURISCVState *env, int csrno,
target_ulong *val)
static target_ulong get_ticks(bool shift)
{
#if !defined(CONFIG_USER_ONLY)
if (icount_enabled()) {
*val = icount_get();
} else {
*val = cpu_get_host_ticks();
}
#else
*val = cpu_get_host_ticks();
#endif
return RISCV_EXCP_NONE;
}
int64_t val;
target_ulong result;
static RISCVException read_instreth(CPURISCVState *env, int csrno,
target_ulong *val)
{
#if !defined(CONFIG_USER_ONLY)
if (icount_enabled()) {
*val = icount_get() >> 32;
val = icount_get();
} else {
*val = cpu_get_host_ticks() >> 32;
val = cpu_get_host_ticks();
}
#else
*val = cpu_get_host_ticks() >> 32;
val = cpu_get_host_ticks();
#endif
return RISCV_EXCP_NONE;
if (shift) {
result = val >> 32;
} else {
result = val;
}
return result;
}
#if defined(CONFIG_USER_ONLY)
@ -642,11 +637,23 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno,
return RISCV_EXCP_NONE;
}
static int read_hpmcounter(CPURISCVState *env, int csrno, target_ulong *val)
{
*val = get_ticks(false);
return RISCV_EXCP_NONE;
}
static int read_hpmcounterh(CPURISCVState *env, int csrno, target_ulong *val)
{
*val = get_ticks(true);
return RISCV_EXCP_NONE;
}
#else /* CONFIG_USER_ONLY */
static int read_mhpmevent(CPURISCVState *env, int csrno, target_ulong *val)
{
int evt_index = csrno - CSR_MHPMEVENT3;
int evt_index = csrno - CSR_MCOUNTINHIBIT;
*val = env->mhpmevent_val[evt_index];
@ -655,7 +662,7 @@ static int read_mhpmevent(CPURISCVState *env, int csrno, target_ulong *val)
static int write_mhpmevent(CPURISCVState *env, int csrno, target_ulong val)
{
int evt_index = csrno - CSR_MHPMEVENT3;
int evt_index = csrno - CSR_MCOUNTINHIBIT;
env->mhpmevent_val[evt_index] = val;
@ -664,55 +671,105 @@ static int write_mhpmevent(CPURISCVState *env, int csrno, target_ulong val)
static int write_mhpmcounter(CPURISCVState *env, int csrno, target_ulong val)
{
int ctr_index = csrno - CSR_MHPMCOUNTER3 + 3;
int ctr_idx = csrno - CSR_MCYCLE;
PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
env->mhpmcounter_val[ctr_index] = val;
counter->mhpmcounter_val = val;
if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
counter->mhpmcounter_prev = get_ticks(false);
} else {
/* Other counters can keep incrementing from the given value */
counter->mhpmcounter_prev = val;
}
return RISCV_EXCP_NONE;
}
static int write_mhpmcounterh(CPURISCVState *env, int csrno, target_ulong val)
{
int ctr_index = csrno - CSR_MHPMCOUNTER3H + 3;
int ctr_idx = csrno - CSR_MCYCLEH;
PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
env->mhpmcounterh_val[ctr_index] = val;
counter->mhpmcounterh_val = val;
if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
counter->mhpmcounterh_prev = get_ticks(true);
} else {
counter->mhpmcounterh_prev = val;
}
return RISCV_EXCP_NONE;
}
static RISCVException riscv_pmu_read_ctr(CPURISCVState *env, target_ulong *val,
bool upper_half, uint32_t ctr_idx)
{
PMUCTRState counter = env->pmu_ctrs[ctr_idx];
target_ulong ctr_prev = upper_half ? counter.mhpmcounterh_prev :
counter.mhpmcounter_prev;
target_ulong ctr_val = upper_half ? counter.mhpmcounterh_val :
counter.mhpmcounter_val;
if (get_field(env->mcountinhibit, BIT(ctr_idx))) {
/**
* Counter should not increment if inhibit bit is set. We can't really
* stop the icount counting. Just return the counter value written by
* the supervisor to indicate that counter was not incremented.
*/
if (!counter.started) {
*val = ctr_val;
return RISCV_EXCP_NONE;
} else {
/* Mark that the counter has been stopped */
counter.started = false;
}
}
/**
* The kernel computes the perf delta by subtracting the current value from
* the value it initialized previously (ctr_val).
*/
if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
*val = get_ticks(upper_half) - ctr_prev + ctr_val;
} else {
*val = ctr_val;
}
return RISCV_EXCP_NONE;
}
static int read_hpmcounter(CPURISCVState *env, int csrno, target_ulong *val)
{
int ctr_index;
uint16_t ctr_index;
if (csrno >= CSR_MCYCLE && csrno <= CSR_MHPMCOUNTER31) {
ctr_index = csrno - CSR_MHPMCOUNTER3 + 3;
ctr_index = csrno - CSR_MCYCLE;
} else if (csrno >= CSR_CYCLE && csrno <= CSR_HPMCOUNTER31) {
ctr_index = csrno - CSR_HPMCOUNTER3 + 3;
ctr_index = csrno - CSR_CYCLE;
} else {
return RISCV_EXCP_ILLEGAL_INST;
}
*val = env->mhpmcounter_val[ctr_index];
return RISCV_EXCP_NONE;
return riscv_pmu_read_ctr(env, val, false, ctr_index);
}
static int read_hpmcounterh(CPURISCVState *env, int csrno, target_ulong *val)
{
int ctr_index;
uint16_t ctr_index;
if (csrno >= CSR_MCYCLEH && csrno <= CSR_MHPMCOUNTER31H) {
ctr_index = csrno - CSR_MHPMCOUNTER3H + 3;
ctr_index = csrno - CSR_MCYCLEH;
} else if (csrno >= CSR_CYCLEH && csrno <= CSR_HPMCOUNTER31H) {
ctr_index = csrno - CSR_HPMCOUNTER3H + 3;
ctr_index = csrno - CSR_CYCLEH;
} else {
return RISCV_EXCP_ILLEGAL_INST;
}
*val = env->mhpmcounterh_val[ctr_index];
return RISCV_EXCP_NONE;
return riscv_pmu_read_ctr(env, val, true, ctr_index);
}
static RISCVException read_time(CPURISCVState *env, int csrno,
target_ulong *val)
{
@ -1567,11 +1624,23 @@ static RISCVException read_mcountinhibit(CPURISCVState *env, int csrno,
static RISCVException write_mcountinhibit(CPURISCVState *env, int csrno,
target_ulong val)
{
int cidx;
PMUCTRState *counter;
if (env->priv_ver < PRIV_VERSION_1_11_0) {
return RISCV_EXCP_ILLEGAL_INST;
}
env->mcountinhibit = val;
/* Check if any other counter is also monitoring cycles/instructions */
for (cidx = 0; cidx < RV_MAX_MHPMCOUNTERS; cidx++) {
if (!get_field(env->mcountinhibit, BIT(cidx))) {
counter = &env->pmu_ctrs[cidx];
counter->started = true;
}
}
return RISCV_EXCP_NONE;
}
@ -3533,10 +3602,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
[CSR_VLENB] = { "vlenb", vs, read_vlenb,
.min_priv_ver = PRIV_VERSION_1_12_0 },
/* User Timers and Counters */
[CSR_CYCLE] = { "cycle", ctr, read_instret },
[CSR_INSTRET] = { "instret", ctr, read_instret },
[CSR_CYCLEH] = { "cycleh", ctr32, read_instreth },
[CSR_INSTRETH] = { "instreth", ctr32, read_instreth },
[CSR_CYCLE] = { "cycle", ctr, read_hpmcounter },
[CSR_INSTRET] = { "instret", ctr, read_hpmcounter },
[CSR_CYCLEH] = { "cycleh", ctr32, read_hpmcounterh },
[CSR_INSTRETH] = { "instreth", ctr32, read_hpmcounterh },
/*
* In privileged mode, the monitor will have to emulate TIME CSRs only if
@ -3550,10 +3619,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
#if !defined(CONFIG_USER_ONLY)
/* Machine Timers and Counters */
[CSR_MCYCLE] = { "mcycle", any, read_instret },
[CSR_MINSTRET] = { "minstret", any, read_instret },
[CSR_MCYCLEH] = { "mcycleh", any32, read_instreth },
[CSR_MINSTRETH] = { "minstreth", any32, read_instreth },
[CSR_MCYCLE] = { "mcycle", any, read_hpmcounter, write_mhpmcounter},
[CSR_MINSTRET] = { "minstret", any, read_hpmcounter, write_mhpmcounter},
[CSR_MCYCLEH] = { "mcycleh", any32, read_hpmcounterh, write_mhpmcounterh},
[CSR_MINSTRETH] = { "minstreth", any32, read_hpmcounterh, write_mhpmcounterh},
/* Machine Information Registers */
[CSR_MVENDORID] = { "mvendorid", any, read_mvendorid },

25
target/riscv/machine.c
View File

@ -279,7 +279,28 @@ static const VMStateDescription vmstate_envcfg = {
VMSTATE_UINT64(env.menvcfg, RISCVCPU),
VMSTATE_UINTTL(env.senvcfg, RISCVCPU),
VMSTATE_UINT64(env.henvcfg, RISCVCPU),
VMSTATE_END_OF_LIST()
}
};
static bool pmu_needed(void *opaque)
{
RISCVCPU *cpu = opaque;
return cpu->cfg.pmu_num;
}
static const VMStateDescription vmstate_pmu_ctr_state = {
.name = "cpu/pmu",
.version_id = 1,
.minimum_version_id = 1,
.needed = pmu_needed,
.fields = (VMStateField[]) {
VMSTATE_UINTTL(mhpmcounter_val, PMUCTRState),
VMSTATE_UINTTL(mhpmcounterh_val, PMUCTRState),
VMSTATE_UINTTL(mhpmcounter_prev, PMUCTRState),
VMSTATE_UINTTL(mhpmcounterh_prev, PMUCTRState),
VMSTATE_BOOL(started, PMUCTRState),
VMSTATE_END_OF_LIST()
}
};
@ -331,8 +352,8 @@ const VMStateDescription vmstate_riscv_cpu = {
VMSTATE_UINTTL(env.scounteren, RISCVCPU),
VMSTATE_UINTTL(env.mcounteren, RISCVCPU),
VMSTATE_UINTTL(env.mcountinhibit, RISCVCPU),
VMSTATE_UINTTL_ARRAY(env.mhpmcounter_val, RISCVCPU, RV_MAX_MHPMCOUNTERS),
VMSTATE_UINTTL_ARRAY(env.mhpmcounterh_val, RISCVCPU, RV_MAX_MHPMCOUNTERS),
VMSTATE_STRUCT_ARRAY(env.pmu_ctrs, RISCVCPU, RV_MAX_MHPMCOUNTERS, 0,
vmstate_pmu_ctr_state, PMUCTRState),
VMSTATE_UINTTL_ARRAY(env.mhpmevent_val, RISCVCPU, RV_MAX_MHPMEVENTS),
VMSTATE_UINTTL(env.sscratch, RISCVCPU),
VMSTATE_UINTTL(env.mscratch, RISCVCPU),

3
target/riscv/meson.build
View File

@ -30,7 +30,8 @@ riscv_softmmu_ss.add(files(
'pmp.c',
'debug.c',
'monitor.c',
'machine.c'
'machine.c',
'pmu.c'
))
target_arch += {'riscv': riscv_ss}

32
target/riscv/pmu.c Normal file
View File

@ -0,0 +1,32 @@
/*
* 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"
bool riscv_pmu_ctr_monitor_instructions(CPURISCVState *env,
uint32_t target_ctr)
{
return (target_ctr == 0) ? true : false;
}
bool riscv_pmu_ctr_monitor_cycles(CPURISCVState *env, uint32_t target_ctr)
{
return (target_ctr == 2) ? true : false;
}

28
target/riscv/pmu.h Normal file
View File

@ -0,0 +1,28 @@
/*
* RISC-V PMU header 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 "qemu/log.h"
#include "cpu.h"
#include "qemu/main-loop.h"
#include "exec/exec-all.h"
bool riscv_pmu_ctr_monitor_instructions(CPURISCVState *env,
uint32_t target_ctr);
bool riscv_pmu_ctr_monitor_cycles(CPURISCVState *env,
uint32_t target_ctr);