stimecmp allows the supervisor mode to update stimecmp CSR directly
to program the next timer interrupt. This CSR is part of the Sstc
extension which was ratified recently.
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
target/riscv/cpu.c | 9 ++++
target/riscv/cpu.h | 5 ++
target/riscv/cpu_bits.h | 4 ++
target/riscv/csr.c | 77 ++++++++++++++++++++++++++++++
target/riscv/machine.c | 1 +
target/riscv/meson.build | 3 +-
target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
target/riscv/time_helper.h | 30 ++++++++++++
8 files changed, 226 insertions(+), 1 deletion(-)
create mode 100644 target/riscv/time_helper.c
create mode 100644 target/riscv/time_helper.h
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index d4635c7df46b..2498b93105fd 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -23,6 +23,7 @@
#include "qemu/log.h"
#include "cpu.h"
#include "internals.h"
+#include "time_helper.h"
#include "exec/exec-all.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
@@ -99,6 +100,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0, ext_zhinxmin),
+ ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0, ext_svinval),
ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0, ext_svnapot),
ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
@@ -675,6 +677,12 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
set_resetvec(env, cpu->cfg.resetvec);
+#ifndef CONFIG_USER_ONLY
+ if (cpu->cfg.ext_sstc) {
+ riscv_timer_init(cpu);
+ }
+#endif /* CONFIG_USER_ONLY */
+
/* Validate that MISA_MXL is set properly. */
switch (env->misa_mxl_max) {
#ifdef TARGET_RISCV64
@@ -995,6 +1003,7 @@ static Property riscv_cpu_extensions[] = {
DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
+ DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 0fae1569945c..4cda2905661e 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -309,6 +309,9 @@ struct CPUArchState {
uint64_t mfromhost;
uint64_t mtohost;
+ /* Sstc CSRs */
+ uint64_t stimecmp;
+
/* physical memory protection */
pmp_table_t pmp_state;
target_ulong mseccfg;
@@ -362,6 +365,7 @@ struct CPUArchState {
float_status fp_status;
/* Fields from here on are preserved across CPU reset. */
+ QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
hwaddr kernel_addr;
hwaddr fdt_addr;
@@ -425,6 +429,7 @@ struct RISCVCPUConfig {
bool ext_ifencei;
bool ext_icsr;
bool ext_zihintpause;
+ bool ext_sstc;
bool ext_svinval;
bool ext_svnapot;
bool ext_svpbmt;
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 6be5a9e9f046..ac17cf1515c0 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -206,6 +206,10 @@
#define CSR_STVAL 0x143
#define CSR_SIP 0x144
+/* Sstc supervisor CSRs */
+#define CSR_STIMECMP 0x14D
+#define CSR_STIMECMPH 0x15D
+
/* Supervisor Protection and Translation */
#define CSR_SPTBR 0x180
#define CSR_SATP 0x180
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 0fb042b2fd0f..e18b000700e4 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -22,6 +22,7 @@
#include "qemu/timer.h"
#include "cpu.h"
#include "pmu.h"
+#include "time_helper.h"
#include "qemu/main-loop.h"
#include "exec/exec-all.h"
#include "sysemu/cpu-timers.h"
@@ -803,6 +804,72 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno,
return RISCV_EXCP_NONE;
}
+static RISCVException sstc(CPURISCVState *env, int csrno)
+{
+ CPUState *cs = env_cpu(env);
+ RISCVCPU *cpu = RISCV_CPU(cs);
+
+ if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
+ return RISCV_EXCP_ILLEGAL_INST;
+ }
+
+ if (env->priv == PRV_M) {
+ return RISCV_EXCP_NONE;
+ }
+
+ /*
+ * No need of separate function for rv32 as menvcfg stores both menvcfg
+ * menvcfgh for RV32.
+ */
+ if (!(get_field(env->mcounteren, COUNTEREN_TM) &&
+ get_field(env->menvcfg, MENVCFG_STCE))) {
+ return RISCV_EXCP_ILLEGAL_INST;
+ }
+
+ return smode(env, csrno);
+}
+
+static RISCVException read_stimecmp(CPURISCVState *env, int csrno,
+ target_ulong *val)
+{
+ *val = env->stimecmp;
+ return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_stimecmph(CPURISCVState *env, int csrno,
+ target_ulong *val)
+{
+ *val = env->stimecmp >> 32;
+ return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_stimecmp(CPURISCVState *env, int csrno,
+ target_ulong val)
+{
+ RISCVCPU *cpu = env_archcpu(env);
+
+ if (riscv_cpu_mxl(env) == MXL_RV32) {
+ env->stimecmp = deposit64(env->stimecmp, 0, 32, (uint64_t)val);
+ } else {
+ env->stimecmp = val;
+ }
+
+ riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
+
+ return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_stimecmph(CPURISCVState *env, int csrno,
+ target_ulong val)
+{
+ RISCVCPU *cpu = env_archcpu(env);
+
+ env->stimecmp = deposit64(env->stimecmp, 32, 32, (uint64_t)val);
+ riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
+
+ return RISCV_EXCP_NONE;
+}
+
/* Machine constants */
#define M_MODE_INTERRUPTS ((uint64_t)(MIP_MSIP | MIP_MTIP | MIP_MEIP))
@@ -1719,6 +1786,12 @@ static RISCVException rmw_mip64(CPURISCVState *env, int csrno,
new_val |= env->external_seip * MIP_SEIP;
}
+ if (cpu->cfg.ext_sstc && (env->priv == PRV_M) &&
+ get_field(env->menvcfg, MENVCFG_STCE)) {
+ /* sstc extension forbids STIP & VSTIP to be writeable in mip */
+ mask = mask & ~(MIP_STIP | MIP_VSTIP);
+ }
+
if (mask) {
old_mip = riscv_cpu_update_mip(cpu, mask, (new_val & mask));
} else {
@@ -3584,6 +3657,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
[CSR_SCAUSE] = { "scause", smode, read_scause, write_scause },
[CSR_STVAL] = { "stval", smode, read_stval, write_stval },
[CSR_SIP] = { "sip", smode, NULL, NULL, rmw_sip },
+ [CSR_STIMECMP] = { "stimecmp", sstc, read_stimecmp, write_stimecmp,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_STIMECMPH] = { "stimecmph", sstc, read_stimecmph, write_stimecmph,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
/* Supervisor Protection and Translation */
[CSR_SATP] = { "satp", smode, read_satp, write_satp },
diff --git a/target/riscv/machine.c b/target/riscv/machine.c
index b508b042cb73..622fface484e 100644
--- a/target/riscv/machine.c
+++ b/target/riscv/machine.c
@@ -359,6 +359,7 @@ const VMStateDescription vmstate_riscv_cpu = {
VMSTATE_UINTTL(env.mscratch, RISCVCPU),
VMSTATE_UINT64(env.mfromhost, RISCVCPU),
VMSTATE_UINT64(env.mtohost, RISCVCPU),
+ VMSTATE_UINT64(env.stimecmp, RISCVCPU),
VMSTATE_END_OF_LIST()
},
diff --git a/target/riscv/meson.build b/target/riscv/meson.build
index 2c1975e72c4e..24893c614ee4 100644
--- a/target/riscv/meson.build
+++ b/target/riscv/meson.build
@@ -31,7 +31,8 @@ riscv_softmmu_ss.add(files(
'debug.c',
'monitor.c',
'machine.c',
- 'pmu.c'
+ 'pmu.c',
+ 'time_helper.c'
))
target_arch += {'riscv': riscv_ss}
diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
new file mode 100644
index 000000000000..f3fb5eac7b7b
--- /dev/null
+++ b/target/riscv/time_helper.c
@@ -0,0 +1,98 @@
+/*
+ * RISC-V timer helper implementation.
+ *
+ * Copyright (c) 2022 Rivos Inc.
+ *
+ * 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_bits.h"
+#include "time_helper.h"
+#include "hw/intc/riscv_aclint.h"
+
+static void riscv_stimer_cb(void *opaque)
+{
+ RISCVCPU *cpu = opaque;
+ riscv_cpu_update_mip(cpu, MIP_STIP, BOOL_TO_MASK(1));
+}
+
+/*
+ * Called when timecmp is written to update the QEMU timer or immediately
+ * trigger timer interrupt if mtimecmp <= current timer value.
+ */
+void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
+ uint64_t timecmp, uint64_t delta,
+ uint32_t timer_irq)
+{
+ uint64_t diff, ns_diff, next;
+ CPURISCVState *env = &cpu->env;
+ RISCVAclintMTimerState *mtimer = env->rdtime_fn_arg;
+ uint32_t timebase_freq = mtimer->timebase_freq;
+ uint64_t rtc_r = env->rdtime_fn(env->rdtime_fn_arg) + delta;
+
+ if (timecmp <= rtc_r) {
+ /*
+ * If we're setting an stimecmp value in the "past",
+ * immediately raise the timer interrupt
+ */
+ riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(1));
+ return;
+ }
+
+ /* Clear the [V]STIP bit in mip */
+ riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(0));
+
+ /* otherwise, set up the future timer interrupt */
+ diff = timecmp - rtc_r;
+ /* back to ns (note args switched in muldiv64) */
+ ns_diff = muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
+
+ /*
+ * check if ns_diff overflowed and check if the addition would potentially
+ * overflow
+ */
+ if ((NANOSECONDS_PER_SECOND > timebase_freq && ns_diff < diff) ||
+ ns_diff > INT64_MAX) {
+ next = INT64_MAX;
+ } else {
+ /*
+ * as it is very unlikely qemu_clock_get_ns will return a value
+ * greater than INT64_MAX, no additional check is needed for an
+ * unsigned integer overflow.
+ */
+ next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns_diff;
+ /*
+ * if ns_diff is INT64_MAX next may still be outside the range
+ * of a signed integer.
+ */
+ next = MIN(next, INT64_MAX);
+ }
+
+ timer_mod(timer, next);
+}
+
+void riscv_timer_init(RISCVCPU *cpu)
+{
+ CPURISCVState *env;
+
+ if (!cpu) {
+ return;
+ }
+
+ env = &cpu->env;
+ env->stimer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &riscv_stimer_cb, cpu);
+ env->stimecmp = 0;
+
+}
diff --git a/target/riscv/time_helper.h b/target/riscv/time_helper.h
new file mode 100644
index 000000000000..7b3cdcc35020
--- /dev/null
+++ b/target/riscv/time_helper.h
@@ -0,0 +1,30 @@
+/*
+ * RISC-V timer header file.
+ *
+ * Copyright (c) 2022 Rivos Inc.
+ *
+ * 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/>.
+ */
+
+#ifndef RISCV_TIME_HELPER_H
+#define RISCV_TIME_HELPER_H
+
+#include "cpu.h"
+#include "qemu/timer.h"
+
+void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
+ uint64_t timecmp, uint64_t delta,
+ uint32_t timer_irq);
+void riscv_timer_init(RISCVCPU *cpu);
+
+#endif
--
2.25.1On Thu, Aug 4, 2022 at 11:47 AM Atish Patra <atishp@rivosinc.com> wrote:
>
> stimecmp allows the supervisor mode to update stimecmp CSR directly
> to program the next timer interrupt. This CSR is part of the Sstc
> extension which was ratified recently.
>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Alistair
> ---
> target/riscv/cpu.c | 9 ++++
> target/riscv/cpu.h | 5 ++
> target/riscv/cpu_bits.h | 4 ++
> target/riscv/csr.c | 77 ++++++++++++++++++++++++++++++
> target/riscv/machine.c | 1 +
> target/riscv/meson.build | 3 +-
> target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
> target/riscv/time_helper.h | 30 ++++++++++++
> 8 files changed, 226 insertions(+), 1 deletion(-)
> create mode 100644 target/riscv/time_helper.c
> create mode 100644 target/riscv/time_helper.h
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index d4635c7df46b..2498b93105fd 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -23,6 +23,7 @@
> #include "qemu/log.h"
> #include "cpu.h"
> #include "internals.h"
> +#include "time_helper.h"
> #include "exec/exec-all.h"
> #include "qapi/error.h"
> #include "qemu/error-report.h"
> @@ -99,6 +100,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
> ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
> ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
> ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0, ext_zhinxmin),
> + ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
> ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0, ext_svinval),
> ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0, ext_svnapot),
> ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
> @@ -675,6 +677,12 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
>
> set_resetvec(env, cpu->cfg.resetvec);
>
> +#ifndef CONFIG_USER_ONLY
> + if (cpu->cfg.ext_sstc) {
> + riscv_timer_init(cpu);
> + }
> +#endif /* CONFIG_USER_ONLY */
> +
> /* Validate that MISA_MXL is set properly. */
> switch (env->misa_mxl_max) {
> #ifdef TARGET_RISCV64
> @@ -995,6 +1003,7 @@ static Property riscv_cpu_extensions[] = {
> DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
> DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
> DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
> + DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
>
> DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
> DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0fae1569945c..4cda2905661e 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -309,6 +309,9 @@ struct CPUArchState {
> uint64_t mfromhost;
> uint64_t mtohost;
>
> + /* Sstc CSRs */
> + uint64_t stimecmp;
> +
> /* physical memory protection */
> pmp_table_t pmp_state;
> target_ulong mseccfg;
> @@ -362,6 +365,7 @@ struct CPUArchState {
> float_status fp_status;
>
> /* Fields from here on are preserved across CPU reset. */
> + QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
>
> hwaddr kernel_addr;
> hwaddr fdt_addr;
> @@ -425,6 +429,7 @@ struct RISCVCPUConfig {
> bool ext_ifencei;
> bool ext_icsr;
> bool ext_zihintpause;
> + bool ext_sstc;
> bool ext_svinval;
> bool ext_svnapot;
> bool ext_svpbmt;
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 6be5a9e9f046..ac17cf1515c0 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -206,6 +206,10 @@
> #define CSR_STVAL 0x143
> #define CSR_SIP 0x144
>
> +/* Sstc supervisor CSRs */
> +#define CSR_STIMECMP 0x14D
> +#define CSR_STIMECMPH 0x15D
> +
> /* Supervisor Protection and Translation */
> #define CSR_SPTBR 0x180
> #define CSR_SATP 0x180
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 0fb042b2fd0f..e18b000700e4 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -22,6 +22,7 @@
> #include "qemu/timer.h"
> #include "cpu.h"
> #include "pmu.h"
> +#include "time_helper.h"
> #include "qemu/main-loop.h"
> #include "exec/exec-all.h"
> #include "sysemu/cpu-timers.h"
> @@ -803,6 +804,72 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno,
> return RISCV_EXCP_NONE;
> }
>
> +static RISCVException sstc(CPURISCVState *env, int csrno)
> +{
> + CPUState *cs = env_cpu(env);
> + RISCVCPU *cpu = RISCV_CPU(cs);
> +
> + if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
> + return RISCV_EXCP_ILLEGAL_INST;
> + }
> +
> + if (env->priv == PRV_M) {
> + return RISCV_EXCP_NONE;
> + }
> +
> + /*
> + * No need of separate function for rv32 as menvcfg stores both menvcfg
> + * menvcfgh for RV32.
> + */
> + if (!(get_field(env->mcounteren, COUNTEREN_TM) &&
> + get_field(env->menvcfg, MENVCFG_STCE))) {
> + return RISCV_EXCP_ILLEGAL_INST;
> + }
> +
> + return smode(env, csrno);
> +}
> +
> +static RISCVException read_stimecmp(CPURISCVState *env, int csrno,
> + target_ulong *val)
> +{
> + *val = env->stimecmp;
> + return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_stimecmph(CPURISCVState *env, int csrno,
> + target_ulong *val)
> +{
> + *val = env->stimecmp >> 32;
> + return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_stimecmp(CPURISCVState *env, int csrno,
> + target_ulong val)
> +{
> + RISCVCPU *cpu = env_archcpu(env);
> +
> + if (riscv_cpu_mxl(env) == MXL_RV32) {
> + env->stimecmp = deposit64(env->stimecmp, 0, 32, (uint64_t)val);
> + } else {
> + env->stimecmp = val;
> + }
> +
> + riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
> +
> + return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_stimecmph(CPURISCVState *env, int csrno,
> + target_ulong val)
> +{
> + RISCVCPU *cpu = env_archcpu(env);
> +
> + env->stimecmp = deposit64(env->stimecmp, 32, 32, (uint64_t)val);
> + riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
> +
> + return RISCV_EXCP_NONE;
> +}
> +
> /* Machine constants */
>
> #define M_MODE_INTERRUPTS ((uint64_t)(MIP_MSIP | MIP_MTIP | MIP_MEIP))
> @@ -1719,6 +1786,12 @@ static RISCVException rmw_mip64(CPURISCVState *env, int csrno,
> new_val |= env->external_seip * MIP_SEIP;
> }
>
> + if (cpu->cfg.ext_sstc && (env->priv == PRV_M) &&
> + get_field(env->menvcfg, MENVCFG_STCE)) {
> + /* sstc extension forbids STIP & VSTIP to be writeable in mip */
> + mask = mask & ~(MIP_STIP | MIP_VSTIP);
> + }
> +
> if (mask) {
> old_mip = riscv_cpu_update_mip(cpu, mask, (new_val & mask));
> } else {
> @@ -3584,6 +3657,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
> [CSR_SCAUSE] = { "scause", smode, read_scause, write_scause },
> [CSR_STVAL] = { "stval", smode, read_stval, write_stval },
> [CSR_SIP] = { "sip", smode, NULL, NULL, rmw_sip },
> + [CSR_STIMECMP] = { "stimecmp", sstc, read_stimecmp, write_stimecmp,
> + .min_priv_ver = PRIV_VERSION_1_12_0 },
> + [CSR_STIMECMPH] = { "stimecmph", sstc, read_stimecmph, write_stimecmph,
> + .min_priv_ver = PRIV_VERSION_1_12_0 },
>
> /* Supervisor Protection and Translation */
> [CSR_SATP] = { "satp", smode, read_satp, write_satp },
> diff --git a/target/riscv/machine.c b/target/riscv/machine.c
> index b508b042cb73..622fface484e 100644
> --- a/target/riscv/machine.c
> +++ b/target/riscv/machine.c
> @@ -359,6 +359,7 @@ const VMStateDescription vmstate_riscv_cpu = {
> VMSTATE_UINTTL(env.mscratch, RISCVCPU),
> VMSTATE_UINT64(env.mfromhost, RISCVCPU),
> VMSTATE_UINT64(env.mtohost, RISCVCPU),
> + VMSTATE_UINT64(env.stimecmp, RISCVCPU),
>
> VMSTATE_END_OF_LIST()
> },
> diff --git a/target/riscv/meson.build b/target/riscv/meson.build
> index 2c1975e72c4e..24893c614ee4 100644
> --- a/target/riscv/meson.build
> +++ b/target/riscv/meson.build
> @@ -31,7 +31,8 @@ riscv_softmmu_ss.add(files(
> 'debug.c',
> 'monitor.c',
> 'machine.c',
> - 'pmu.c'
> + 'pmu.c',
> + 'time_helper.c'
> ))
>
> target_arch += {'riscv': riscv_ss}
> diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
> new file mode 100644
> index 000000000000..f3fb5eac7b7b
> --- /dev/null
> +++ b/target/riscv/time_helper.c
> @@ -0,0 +1,98 @@
> +/*
> + * RISC-V timer helper implementation.
> + *
> + * Copyright (c) 2022 Rivos Inc.
> + *
> + * 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_bits.h"
> +#include "time_helper.h"
> +#include "hw/intc/riscv_aclint.h"
> +
> +static void riscv_stimer_cb(void *opaque)
> +{
> + RISCVCPU *cpu = opaque;
> + riscv_cpu_update_mip(cpu, MIP_STIP, BOOL_TO_MASK(1));
> +}
> +
> +/*
> + * Called when timecmp is written to update the QEMU timer or immediately
> + * trigger timer interrupt if mtimecmp <= current timer value.
> + */
> +void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
> + uint64_t timecmp, uint64_t delta,
> + uint32_t timer_irq)
> +{
> + uint64_t diff, ns_diff, next;
> + CPURISCVState *env = &cpu->env;
> + RISCVAclintMTimerState *mtimer = env->rdtime_fn_arg;
> + uint32_t timebase_freq = mtimer->timebase_freq;
> + uint64_t rtc_r = env->rdtime_fn(env->rdtime_fn_arg) + delta;
> +
> + if (timecmp <= rtc_r) {
> + /*
> + * If we're setting an stimecmp value in the "past",
> + * immediately raise the timer interrupt
> + */
> + riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(1));
> + return;
> + }
> +
> + /* Clear the [V]STIP bit in mip */
> + riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(0));
> +
> + /* otherwise, set up the future timer interrupt */
> + diff = timecmp - rtc_r;
> + /* back to ns (note args switched in muldiv64) */
> + ns_diff = muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
> +
> + /*
> + * check if ns_diff overflowed and check if the addition would potentially
> + * overflow
> + */
> + if ((NANOSECONDS_PER_SECOND > timebase_freq && ns_diff < diff) ||
> + ns_diff > INT64_MAX) {
> + next = INT64_MAX;
> + } else {
> + /*
> + * as it is very unlikely qemu_clock_get_ns will return a value
> + * greater than INT64_MAX, no additional check is needed for an
> + * unsigned integer overflow.
> + */
> + next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns_diff;
> + /*
> + * if ns_diff is INT64_MAX next may still be outside the range
> + * of a signed integer.
> + */
> + next = MIN(next, INT64_MAX);
> + }
> +
> + timer_mod(timer, next);
> +}
> +
> +void riscv_timer_init(RISCVCPU *cpu)
> +{
> + CPURISCVState *env;
> +
> + if (!cpu) {
> + return;
> + }
> +
> + env = &cpu->env;
> + env->stimer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &riscv_stimer_cb, cpu);
> + env->stimecmp = 0;
> +
> +}
> diff --git a/target/riscv/time_helper.h b/target/riscv/time_helper.h
> new file mode 100644
> index 000000000000..7b3cdcc35020
> --- /dev/null
> +++ b/target/riscv/time_helper.h
> @@ -0,0 +1,30 @@
> +/*
> + * RISC-V timer header file.
> + *
> + * Copyright (c) 2022 Rivos Inc.
> + *
> + * 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/>.
> + */
> +
> +#ifndef RISCV_TIME_HELPER_H
> +#define RISCV_TIME_HELPER_H
> +
> +#include "cpu.h"
> +#include "qemu/timer.h"
> +
> +void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
> + uint64_t timecmp, uint64_t delta,
> + uint32_t timer_irq);
> +void riscv_timer_init(RISCVCPU *cpu);
> +
> +#endif
> --
> 2.25.1
>
>
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