From 75924457863e9dc90475b5cbd9bcabfff87cfc0d Mon Sep 17 00:00:00 2001
From: Remy Noel <mocramis@gmail.com>
Date: Wed, 18 Apr 2018 19:21:42 +0200
Subject: perfmon: Add overflow handling.

Only architectural version 1 handled so far.
---
 kern/perfmon.c | 36 +++++++++++++++++++++++++-----------
 kern/perfmon.h | 16 ++++++++++++++--
 2 files changed, 39 insertions(+), 13 deletions(-)

(limited to 'kern')

diff --git a/kern/perfmon.c b/kern/perfmon.c
index ed848e3..e91f3cd 100644
--- a/kern/perfmon.c
+++ b/kern/perfmon.c
@@ -44,6 +44,7 @@
 #include <kern/thread.h>
 #include <kern/xcall.h>
 #include <machine/cpu.h>
+#include <machine/trap.h>
 
 /*
  * Performance monitoring event.
@@ -424,6 +425,16 @@ perfmon_cpu_pmc_get_prev(unsigned int pmc_id)
     return cpu_pmc->prev_value;
 }
 
+void
+perfmon_cpu_pmc_set_prev(unsigned int pmc_id, uint64_t prev)
+{
+    struct perfmon_cpu_pmc *cpu_pmc;
+
+    cpu_pmc = perfmon_cpu_pmu_get_pmc_from_id(pmc_id);
+
+    cpu_pmc->prev_value = prev;
+}
+
 void
 perfmon_cpu_pmc_inc_of(unsigned int pmc_id)
 {
@@ -462,6 +473,12 @@ perfmon_cpu_pmu_unload(struct perfmon_cpu_pmu *cpu_pmu, unsigned int pmc_index)
     }
 }
 
+void
+perfmon_handle_of_intr(struct trap_frame *frame)
+{
+    pmu_driver.handle_of_intr(frame);
+}
+
 int
 perfmon_pmu_register(struct perfmon_pmu_ops *driver)
 {
@@ -527,6 +544,11 @@ perfmon_setup(void)
         return ENODEV;
     }
     pmu_driver.info();
+    if (pmu_driver.handle_of_intr) {
+        trap_register(TRAP_LAPIC_PMC_OF, lapic_pmc_of_intr);
+    } else {
+        log_warning("registered pmu does not handle overflow\n");
+    }
 
     return 0;
 }
@@ -540,7 +562,8 @@ INIT_OP_DEFINE(perfmon_setup,
                INIT_OP_DEP(pmu_intel_setup, false),
                INIT_OP_DEP(pmu_amd_setup, false),
                INIT_OP_DEP(spinlock_setup, true),
-               INIT_OP_DEP(thread_setup, true));
+               INIT_OP_DEP(thread_setup, true),
+               INIT_OP_DEP(trap_setup, true));
 
 static void
 perfmon_check_event_args(unsigned int type, unsigned int id, int flags)
@@ -618,14 +641,9 @@ perfmon_event_sync(struct perfmon_cpu_pmu *cpu_pmu,
                         - event->prev + count;
         event->overflow_id = cpu_pmc->overflow_id;
     } else {
-        event->count += (count - event->prev);
+        event->count += count - event->prev;
     }
     event->prev = count;
-
-    /* Update per cpu prev value. we should use a callback "on_sync" or so
-     * instead as it is only necessary for certain archtectural overflow
-     * management.*/
-    cpu_pmc->prev_value = count;
 }
 
 static inline int
@@ -896,10 +914,6 @@ perfmon_group_load(struct perfmon_group *group)
         perfmon_cpu_pmu_load(cpu_pmu, event->pmc_index);
         event->prev = pmu_driver.read(perfmon_pmu.pmcs[event->pmc_index].id);
         event->overflow_id = cpu_pmu->pmcs[event->pmc_index].overflow_id;
-        /* Update per cpu prev value. we should use a callback "on_sync" or so
-         * instead as it is only necessary for certain archtectural overflow
-         * management.*/
-        cpu_pmu->pmcs[event->pmc_index].prev_value = event->prev;
     }
 
     group->cpu = cpu_id();
diff --git a/kern/perfmon.h b/kern/perfmon.h
index 0e5cd19..60e40e0 100644
--- a/kern/perfmon.h
+++ b/kern/perfmon.h
@@ -65,6 +65,7 @@ struct perfmon_pmu_ops {
     void (*stop)(unsigned int pmc_id);
     uint64_t (*read)(unsigned int pmc_id);
     uint8_t (*get_pmc_width)(void);
+    void (*handle_of_intr)(struct trap_frame *frame);
 };
 
 /*
@@ -216,17 +217,28 @@ INIT_OP_DECLARE(perfmon_bootstrap);
  */
 INIT_OP_DECLARE(perfmon_setup);
 
+/*
+ * Handle overflow interrupt.
+ */
+void perfmon_handle_of_intr(struct trap_frame *frame);
+
+int perfmon_on_overflow(struct perfmon_pmu_ops *driver);
+
 /*
  * Register an architecture-specific driver.
  */
-int
-perfmon_pmu_register(struct perfmon_pmu_ops *driver);
+int perfmon_pmu_register(struct perfmon_pmu_ops *driver);
 
 /*
  * Get the last value of given pmc.
  */
 uint64_t perfmon_cpu_pmc_get_prev(unsigned int pmc_id);
 
+/*
+ * Set the last value of given pmc.
+ */
+void perfmon_cpu_pmc_set_prev(unsigned int pmc_id, uint64_t prev);
+
 /*
  * Increment overflow counter for given pmc.
  */
-- 
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