ACPI: Add perf low power callback

mainline inclusion
from mainline-v5.19
commit 2a606a18
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5S3WV
CVE: NA

-------------------------------------------------

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: NStephane Eranian <eranian@google.com>
[peterz: build fix]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220322221517.2510440-9-eranian@google.comSigned-off-by: NXie Haocheng <haocheng.xie@amd.com>

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>
 
@@ -163,6 +164,9 @@ 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();
@@ -171,6 +175,9 @@ 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)) {

drivers/acpi/processor_idle.c

@@ -20,6 +20,7 @@
 #include <linux/tick.h>
 #include <linux/cpuidle.h>
 #include <linux/cpu.h>
+#include <linux/perf_event.h>
 #include <acpi/processor.h>
 
 /*
@@ -551,6 +552,8 @@ 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);
@@ -561,6 +564,8 @@ static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 		inb(cx->address);
 		wait_for_freeze();
 	}
+
+	perf_lopwr_cb(false);
 }
 
 /**

include/linux/perf_event.h

@@ -1624,4 +1624,11 @@ extern void __weak arch_perf_update_userpage(struct perf_event *event,
 					     struct perf_event_mmap_page *userpg,
 					     u64 now);
 
+
+#ifndef PERF_NEEDS_LOPWR_CB
+static inline void perf_lopwr_cb(bool mode)
+{
+}
+#endif
+
 #endif /* _LINUX_PERF_EVENT_H */