mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-27 12:57:53 +00:00
Code Issues Releases Wiki Activity

drivers/perf: riscv_pmu: Add riscv pmu pm notifier

Browse source 
Currently, when the CPU is doing suspend to ram, we don't
save pmu counter register and its content will be lost.

To ensure perf profiling is not affected by suspend to ram,
this patch is based on arm_pmu CPU_PM notifier and implements riscv
pmu pm notifier. In the pm notifier, we stop the counter and update
the counter value before suspend and start the counter after resume.

Signed-off-by: Eric Lin <eric.lin@sifive.com>
Link: https://lore.kernel.org/r/20220705091920.27432-1-eric.lin@sifive.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Eric Lin 2022-07-05 17:19:20 +08:00 committed by Will Deacon
parent e500405dd1
commit e9a023f2b7
3 changed files with 83 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/perf/riscv_pmu.c
View file

@ -121,7 +121,7 @@ u64 riscv_pmu_event_update(struct perf_event *event)
return delta;
}
static void riscv_pmu_stop(struct perf_event *event, int flags)
void riscv_pmu_stop(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
@ -175,7 +175,7 @@ int riscv_pmu_event_set_period(struct perf_event *event)
return overflow;
}
static void riscv_pmu_start(struct perf_event *event, int flags)
void riscv_pmu_start(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);

81
drivers/perf/riscv_pmu_sbi.c
View file

@ -17,6 +17,7 @@
#include <linux/irqdomain.h>
#include <linux/of_irq.h>
#include <linux/of.h>
#include <linux/cpu_pm.h>
#include <asm/sbi.h>
#include <asm/hwcap.h>
@ -693,6 +694,73 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pde
return 0;
}
#ifdef CONFIG_CPU_PM
static int riscv_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
void *v)
{
struct riscv_pmu *rvpmu = container_of(b, struct riscv_pmu, riscv_pm_nb);
struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
int enabled = bitmap_weight(cpuc->used_hw_ctrs, RISCV_MAX_COUNTERS);
struct perf_event *event;
int idx;
if (!enabled)
return NOTIFY_OK;
for (idx = 0; idx < RISCV_MAX_COUNTERS; idx++) {
event = cpuc->events[idx];
if (!event)
continue;
switch (cmd) {
case CPU_PM_ENTER:
/*
* Stop and update the counter
*/
riscv_pmu_stop(event, PERF_EF_UPDATE);
break;
case CPU_PM_EXIT:
case CPU_PM_ENTER_FAILED:
/*
* Restore and enable the counter.
*
* Requires RCU read locking to be functional,
* wrap the call within RCU_NONIDLE to make the
* RCU subsystem aware this cpu is not idle from
* an RCU perspective for the riscv_pmu_start() call
* duration.
*/
RCU_NONIDLE(riscv_pmu_start(event, PERF_EF_RELOAD));
break;
default:
break;
}
}
return NOTIFY_OK;
}
static int riscv_pm_pmu_register(struct riscv_pmu *pmu)
{
pmu->riscv_pm_nb.notifier_call = riscv_pm_pmu_notify;
return cpu_pm_register_notifier(&pmu->riscv_pm_nb);
}
static void riscv_pm_pmu_unregister(struct riscv_pmu *pmu)
{
cpu_pm_unregister_notifier(&pmu->riscv_pm_nb);
}
#else
static inline int riscv_pm_pmu_register(struct riscv_pmu *pmu) { return 0; }
static inline void riscv_pm_pmu_unregister(struct riscv_pmu *pmu) { }
#endif
static void riscv_pmu_destroy(struct riscv_pmu *pmu)
{
riscv_pm_pmu_unregister(pmu);
cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
}
static int pmu_sbi_device_probe(struct platform_device *pdev)
{
struct riscv_pmu *pmu = NULL;
@ -733,14 +801,19 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
if (ret)
return ret;
ret = riscv_pm_pmu_register(pmu);
if (ret)
goto out_unregister;
ret = perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
if (ret) {
cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
return ret;
}
if (ret)
goto out_unregister;
return 0;
out_unregister:
riscv_pmu_destroy(pmu);
out_free:
kfree(pmu);
return ret;

4
include/linux/perf/riscv_pmu.h
View file

@ -56,9 +56,13 @@ struct riscv_pmu {
struct cpu_hw_events __percpu *hw_events;
struct hlist_node node;
struct notifier_block riscv_pm_nb;
};
#define to_riscv_pmu(p) (container_of(p, struct riscv_pmu, pmu))
void riscv_pmu_start(struct perf_event *event, int flags);
void riscv_pmu_stop(struct perf_event *event, int flags);
unsigned long riscv_pmu_ctr_read_csr(unsigned long csr);
int riscv_pmu_event_set_period(struct perf_event *event);
uint64_t riscv_pmu_ctr_get_width_mask(struct perf_event *event);