The following commit has been merged into the perf/core branch of tip: Commit-ID: 2a606a18cd672a16343d146a126721b34cc6adbd Gitweb: https://git.kernel.org/tip/2a606a18cd672a16343d146a126721b34cc6adbd Author: Stephane Eranian <eranian@xxxxxxxxxx> AuthorDate: Tue, 22 Mar 2022 15:15:12 -07:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Tue, 05 Apr 2022 10:24:38 +02:00 ACPI: Add perf low power callback Add an optional callback needed by some PMU features, e.g., AMD BRS, to give a chance to the perf_events code to change its state before a CPU goes to low power and after it comes back. The callback is void when the PERF_NEEDS_LOPWR_CB flag is not set. This flag must be set in arch specific perf_event.h header whenever needed. When not set, there is no impact on the ACPI code. Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx> [peterz: build fix] Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220322221517.2510440-9-eranian@xxxxxxxxxx --- drivers/acpi/acpi_pad.c | 7 +++++++ drivers/acpi/processor_idle.c | 5 +++++ include/linux/perf_event.h | 6 ++++++ 3 files changed, 18 insertions(+) diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c index f45979a..ec0e22a 100644 --- a/drivers/acpi/acpi_pad.c +++ b/drivers/acpi/acpi_pad.c @@ -17,6 +17,7 @@ #include <linux/tick.h> #include <linux/slab.h> #include <linux/acpi.h> +#include <linux/perf_event.h> #include <asm/mwait.h> #include <xen/xen.h> @@ -164,6 +165,9 @@ static int power_saving_thread(void *data) tsc_marked_unstable = 1; } local_irq_disable(); + + perf_lopwr_cb(true); + tick_broadcast_enable(); tick_broadcast_enter(); stop_critical_timings(); @@ -172,6 +176,9 @@ static int power_saving_thread(void *data) start_critical_timings(); tick_broadcast_exit(); + + perf_lopwr_cb(false); + local_irq_enable(); if (time_before(expire_time, jiffies)) { diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 32b20ef..05dc0e1 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -21,6 +21,7 @@ #include <linux/cpuidle.h> #include <linux/cpu.h> #include <linux/minmax.h> +#include <linux/perf_event.h> #include <acpi/processor.h> /* @@ -549,6 +550,8 @@ static void wait_for_freeze(void) */ static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx) { + perf_lopwr_cb(true); + if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -559,6 +562,8 @@ static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx) inb(cx->address); wait_for_freeze(); } + + perf_lopwr_cb(false); } /** diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index a411080..da75956 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1676,4 +1676,10 @@ typedef int (perf_snapshot_branch_stack_t)(struct perf_branch_entry *entries, unsigned int cnt); DECLARE_STATIC_CALL(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t); +#ifndef PERF_NEEDS_LOPWR_CB +static inline void perf_lopwr_cb(bool mode) +{ +} +#endif + #endif /* _LINUX_PERF_EVENT_H */
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