From 82fa1b30dbd7fa64d08237720da3999618c34d6c Mon Sep 17 00:00:00 2001
From: jca <jca@openbsd.org>
Date: Sat, 24 Jul 2021 22:41:09 +0000
Subject: [PATCH] riscv64 userland timecounter support

ok kettenis@
---
 lib/libc/arch/riscv64/gen/usertc.c | 27 +++++++++++++++++++++++++--
 sys/arch/riscv64/include/timetc.h  |  3 ++-
 sys/arch/riscv64/riscv64/clock.c   |  3 ++-
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/lib/libc/arch/riscv64/gen/usertc.c b/lib/libc/arch/riscv64/gen/usertc.c
index 2274976a08f..f0f36b6fa38 100644
--- a/lib/libc/arch/riscv64/gen/usertc.c
+++ b/lib/libc/arch/riscv64/gen/usertc.c
@@ -1,6 +1,7 @@
-/*	$OpenBSD: usertc.c,v 1.1 2021/04/29 18:33:36 drahn Exp $	*/
+/*	$OpenBSD: usertc.c,v 1.2 2021/07/24 22:41:09 jca Exp $	*/
 /*
  * Copyright (c) 2020 Paul Irofti <paul@irofti.net>
+ * Copyright (c) 2021 Jeremie Courreges-Anglas <jca@wxcvbn.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -18,4 +19,26 @@
 #include <sys/types.h>
 #include <sys/timetc.h>
 
-int (*const _tc_get_timecount)(struct timekeep *, u_int *) = NULL;
+static inline u_int
+rdtime(void)
+{
+	uint64_t ret;
+
+	__asm volatile("rdtime %0" : "=r"(ret));
+
+	return ret;
+}
+
+static int
+tc_get_timecount(struct timekeep *tk, u_int *tc)
+{
+	switch (tk->tk_user) {
+	case TC_TB:
+		*tc = rdtime();
+		return 0;
+	}
+
+	return -1;
+}
+
+int (*const _tc_get_timecount)(struct timekeep *, u_int *) = tc_get_timecount;
diff --git a/sys/arch/riscv64/include/timetc.h b/sys/arch/riscv64/include/timetc.h
index 5b5bd942162..284749253cf 100644
--- a/sys/arch/riscv64/include/timetc.h
+++ b/sys/arch/riscv64/include/timetc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: timetc.h,v 1.2 2021/05/12 01:20:52 jsg Exp $	*/
+/*	$OpenBSD: timetc.h,v 1.3 2021/07/24 22:41:09 jca Exp $	*/
 
 /*
  * Copyright (c) 2020 Paul Irofti <paul@irofti.net>
@@ -19,5 +19,6 @@
 #ifndef _MACHINE_TIMETC_H_
 #define _MACHINE_TIMETC_H_
 
+#define TC_TB	1
 
 #endif	/* _MACHINE_TIMETC_H_ */
diff --git a/sys/arch/riscv64/riscv64/clock.c b/sys/arch/riscv64/riscv64/clock.c
index 02984bb4ed8..15b2eaf8c5d 100644
--- a/sys/arch/riscv64/riscv64/clock.c
+++ b/sys/arch/riscv64/riscv64/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.2 2021/06/21 15:19:39 kettenis Exp $	*/
+/*	$OpenBSD: clock.c,v 1.3 2021/07/24 22:41:09 jca Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -47,6 +47,7 @@ static struct timecounter tb_timecounter = {
 	.tc_name = "tb",
 	.tc_quality = 0,
 	.tc_priv = NULL,
+	.tc_user = TC_TB,
 };
 
 void	cpu_startclock(void);
-- 
2.20.1