riscv: Implement non-stub __vdso_gettc and __vdso_gettimekeep

PR:	256905
Reviewed by:	arichardson, mhorne
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D30963

(cherry picked from commit 348c41d1815dc2e872a1deba1f4bf760caaa1094)

5 files changed, 75 insertions, 3 deletions

diff --git a/lib/libc/riscv/sys/Makefile.inc b/lib/libc/riscv/sys/Makefile.inc
index 0e94e6652645..b322cece382c 100644
--- a/lib/libc/riscv/sys/Makefile.inc
+++ b/lib/libc/riscv/sys/Makefile.inc
@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-SRCS+=	trivial-vdso_tc.c
+SRCS+=	__vdso_gettc.c
 
 MDASM=	cerror.S \
 	syscall.S \
diff --git a/lib/libc/riscv/sys/__vdso_gettc.c b/lib/libc/riscv/sys/__vdso_gettc.c
new file mode 100644
index 000000000000..20e69a791bb5
--- /dev/null
+++ b/lib/libc/riscv/sys/__vdso_gettc.c
@@ -0,0 +1,56 @@
+/*-
+ * Copyright (c) 2021 Jessica Clarke
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/elf.h>
+#include <sys/time.h>
+#include <sys/vdso.h>
+
+#include <machine/riscvreg.h>
+
+#include <errno.h>
+
+#include "libc_private.h"
+
+#pragma weak __vdso_gettc
+int
+__vdso_gettc(const struct vdso_timehands *th, u_int *tc)
+{
+	if (th->th_algo != VDSO_TH_ALGO_RISCV_RDTIME)
+		return (ENOSYS);
+
+	*tc = csr_read(time);
+	return (0);
+}
+
+#pragma weak __vdso_gettimekeep
+int
+__vdso_gettimekeep(struct vdso_timekeep **tk)
+{
+	return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
+}
diff --git a/sys/riscv/include/vdso.h b/sys/riscv/include/vdso.h
index 5a8f7f555b50..175c52eedcef 100644
--- a/sys/riscv/include/vdso.h
+++ b/sys/riscv/include/vdso.h
@@ -31,4 +31,6 @@
 #define	VDSO_TIMEHANDS_MD			\
 	uint32_t	th_res[8];
 
+#define	VDSO_TH_ALGO_RISCV_RDTIME	VDSO_TH_ALGO_1
+
 #endif /* !_MACHINE_VDSO_H_ */
diff --git a/sys/riscv/riscv/elf_machdep.c b/sys/riscv/riscv/elf_machdep.c
index cf479ec6d154..5e974aba3701 100644
--- a/sys/riscv/riscv/elf_machdep.c
+++ b/sys/riscv/riscv/elf_machdep.c
@@ -84,8 +84,8 @@ struct sysentvec elf64_freebsd_sysvec = {
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
 	.sv_maxssiz	= NULL,
-	.sv_flags	= SV_ABI_FREEBSD | SV_LP64 | SV_SHP | SV_ASLR |
-	    SV_RNG_SEED_VER,
+	.sv_flags	= SV_ABI_FREEBSD | SV_LP64 | SV_SHP | SV_TIMEKEEP |
+	    SV_ASLR | SV_RNG_SEED_VER,
 	.sv_set_syscall_retval = cpu_set_syscall_retval,
 	.sv_fetch_syscall_args = cpu_fetch_syscall_args,
 	.sv_syscallnames = syscallnames,
diff --git a/sys/riscv/riscv/timer.c b/sys/riscv/riscv/timer.c
index 845a2fbed2ff..c75350f4aac5 100644
--- a/sys/riscv/riscv/timer.c
+++ b/sys/riscv/riscv/timer.c
@@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/rman.h>
 #include <sys/timeet.h>
 #include <sys/timetc.h>
+#include <sys/vdso.h>
 #include <sys/watchdog.h>
 
 #include <sys/proc.h>
@@ -78,6 +79,9 @@ struct riscv_timer_softc {
 
 static struct riscv_timer_softc *riscv_timer_sc = NULL;
 
+static uint32_t riscv_timer_fill_vdso_timehands(struct vdso_timehands *vdso_th,
+    struct timecounter *tc);
+
 static timecounter_get_t riscv_timer_get_timecount;
 
 static struct timecounter riscv_timer_timecount = {
@@ -87,6 +91,7 @@ static struct timecounter riscv_timer_timecount = {
 	.tc_counter_mask   = ~0u,
 	.tc_frequency      = 0,
 	.tc_quality        = 1000,
+	.tc_fill_vdso_timehands = riscv_timer_fill_vdso_timehands,
 };
 
 static inline uint64_t
@@ -301,3 +306,12 @@ DELAY(int usec)
 	}
 	TSEXIT();
 }
+
+static uint32_t
+riscv_timer_fill_vdso_timehands(struct vdso_timehands *vdso_th,
+    struct timecounter *tc)
+{
+	vdso_th->th_algo = VDSO_TH_ALGO_RISCV_RDTIME;
+	bzero(vdso_th->th_res, sizeof(vdso_th->th_res));
+	return (1);
+}