1 files changed, 121 insertions, 0 deletions
diff --git a/kern/syscnt.h b/kern/syscnt.h
new file mode 100644
index 00000000..ff9cedbb
--- /dev/null
+++ b/kern/syscnt.h
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2014-2017 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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/>.
+ *
+ *
+ * System counters.
+ *
+ * This module provides 64-bits general-purpose counters that can be
+ * accessed and modified atomically from any context.
+ */
+
+#ifndef _KERN_SYSCNT_H
+#define _KERN_SYSCNT_H
+
+#include <stdint.h>
+
+#include <kern/macros.h>
+#include <kern/spinlock.h>
+#include <machine/atomic.h>
+
+/*
+ * Size of the buffer storing a system counter name.
+ */
+#define SYSCNT_NAME_SIZE 32
+
+#include <kern/syscnt_types.h>
+
+/*
+ * System counter.
+ */
+struct syscnt;
+
+/*
+ * Initialize the syscnt module.
+ *
+ * This module is initialized by architecture-specific code. It is normally
+ * safe to call this function very early at boot time.
+ */
+void syscnt_setup(void);
+
+/*
+ * Initialize and register the given counter.
+ *
+ * The counter is set to 0.
+ */
+void syscnt_register(struct syscnt *syscnt, const char *name);
+
+#ifdef __LP64__
+
+static inline void
+syscnt_add(struct syscnt *syscnt, int64_t delta)
+{
+    atomic_add_ulong(&syscnt->value, delta);
+}
+
+static inline uint64_t
+syscnt_read(const struct syscnt *syscnt)
+{
+    return read_once(syscnt->value);
+}
+
+#else /* __LP64__ */
+
+static inline void
+syscnt_add(struct syscnt *syscnt, int64_t delta)
+{
+    unsigned long flags;
+
+    spinlock_lock_intr_save(&syscnt->lock, &flags);
+    syscnt->value += delta;
+    spinlock_unlock_intr_restore(&syscnt->lock, flags);
+}
+
+static inline uint64_t
+syscnt_read(const struct syscnt *syscnt)
+{
+    unsigned long flags;
+    uint64_t value;
+
+    spinlock_lock_intr_save(&syscnt->lock, &flags);
+    value = syscnt->value;
+    spinlock_unlock_intr_restore(&syscnt->lock, flags);
+
+    return value;
+}
+
+#endif /* __LP64__ */
+
+static inline void
+syscnt_inc(struct syscnt *syscnt)
+{
+    syscnt_add(syscnt, 1);
+}
+
+static inline void
+syscnt_dec(struct syscnt *syscnt)
+{
+    syscnt_add(syscnt, -1);
+}
+
+/*
+ * Display system counters.
+ *
+ * A prefix can be used to filter the output, where only counters with the
+ * given prefix are displayed. If NULL, all counters are reported.
+ */
+void syscnt_info(const char *prefix);
+
+#endif /* _KERN_SYSCNT_H */