1 files changed, 120 insertions, 0 deletions
diff --git a/src/uapi/timers.c b/src/uapi/timers.c
new file mode 100644
index 0000000..b119fcc
--- /dev/null
+++ b/src/uapi/timers.c
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: copyleft-next-0.3.1 */
+/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
+
+/**
+ * @file timers.c
+ * Timer syscall implementations.
+ */
+
+#include <kmi/timer.h>
+#include <kmi/uapi.h>
+
+#include <arch/timer.h>
+
+/**
+ * Convert arch-specific register values \p ticks and \p mult to \ref ticks_t.
+ *
+ * If we're on a 32bit system, one register can't contain a tick value,
+ * so we use two registers and combine them into one value and let the compiler
+ * handle the rest.
+ *
+ * @param ticks Register width tick value.
+ * @param mult Register width repeat value.
+ * @return Corresponding \ref ticks_t value.
+ */
+static ticks_t scaled_ticks(sys_arg_t ticks, sys_arg_t mult)
+{
+#if defined(_LP64)
+	UNUSED(mult);
+	return ticks;
+#else
+	return (ticks_t)ticks * (ticks_t)mult;
+#endif
+}
+
+/**
+ * Timebase syscall handler.
+ *
+ * @param t Current tcb.
+ * @return \ref OK and timebase in second argument if 64bit, otherwise high 32
+ * bits of timebase in second argument and low 32 bits in third argument.
+ */
+SYSCALL_DEFINE0(timebase)(struct tcb *t)
+{
+	ticks_t tm = secs_to_ticks(1);
+#if defined(_LP64)
+	return_args2(t, OK, tm);
+#else
+	return_args3(t, OK, tm >> 32, tm);
+#endif
+}
+
+/**
+ * Current ticks syscall handler.
+ *
+ * Note that most platforms allow user level read access to hardware timers, and
+ * should be preferred over this syscall on such platforms. Still, for
+ * completeness sake.
+ *
+ * @param t Current tcb.
+ * @return \ref OK and the current ticks when on 64bit systems, otherwise high
+ * 32 bits of ticks in second argument and low 32 bits in third.
+ */
+SYSCALL_DEFINE0(ticks)(struct tcb *t)
+{
+	ticks_t tm = current_ticks();
+#if defined(_LP64)
+	return_args2(t, OK, tm);
+#else
+	return_args3(t, OK, tm >> 32, tm);
+#endif
+}
+
+/**
+ * Relative timer request syscall handler.
+ *
+ * \note On 64bit systems, \p mult is ignored as \p ticks register is large
+ * enough to contain essentially any timepoint we want. A couple thousand years
+ * when the clock runs at 5GHz, if I'm not completely mistaken.
+ *
+ * @param t Current tcb.
+ * @param ticks Number of ticks from now.
+ * @param mult Multiply \c ticks by this value.
+ * @return \ref OK and \c cid of created timer.
+ */
+SYSCALL_DEFINE2(req_rel_timer)(struct tcb *t, sys_arg_t ticks, sys_arg_t mult)
+{
+	return_args2(t, OK, new_rel_timer(t->tid, scaled_ticks(ticks, mult)));
+}
+
+/**
+ * Absolute timer request syscall handler.
+ *
+ * @param t Current tcb.
+ * @param ticks Absolute timepoint relative to some start point defined at boot.
+ * @param mult Multiply \c ticks by this value.
+ * @return \ref OK and \c cid of created timer.
+ * \see req_rel_timer().
+ */
+SYSCALL_DEFINE2(req_abs_timer)(struct tcb *t, sys_arg_t ticks, sys_arg_t mult)
+{
+	return_args2(t, OK, new_abs_timer(t->tid, scaled_ticks(ticks, mult)));
+}
+
+/**
+ * Free timer request syscall handler.
+ *
+ * @param t Current tcb.
+ * @param cid \c cid of timer to free.
+ * @return \ref ERR_NF and \c 0if no timer could be found with \c cid, \ref OK
+ * and 0 otherwise.
+ */
+SYSCALL_DEFINE1(free_timer)(struct tcb *t, sys_arg_t cid)
+{
+	struct timer *timer = find_timer(cid);
+	if (!timer)
+		return_args1(t, ERR_NF);
+
+	remove_timer(timer);
+	return_args1(t, OK);
+}