From: Philippe Gerum <rpm@xenomai.org>
To: xenomai@xenomai.org
Subject: [PATCH 03/13] cobalt/clock: pipeline: abstract access to host (real)time
Date: Sun, 31 Jan 2021 15:45:30 +0100 [thread overview]
Message-ID: <20210131144540.243363-3-rpm@xenomai.org> (raw)
In-Reply-To: <20210131144540.243363-1-rpm@xenomai.org>
From: Philippe Gerum <rpm@xenomai.org>
Dovetail enables applications to get timestamps from the
CLOCK_MONOTONIC and CLOCK_REALTIME clocks via the regular vDSO by
calling clock_gettime(), including from the out-of-band stage
(i.e. primary mode).
Legacy support involving IPIPE_HOSTRT can move to the I-pipe specific
section.
No functional change is introduced.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>
---
include/cobalt/kernel/ipipe/pipeline/clock.h | 4 ++
include/cobalt/uapi/kernel/vdso.h | 5 ++
kernel/cobalt/ipipe/Makefile | 2 +-
kernel/cobalt/ipipe/clock.c | 62 ++++++++++++++++++++
kernel/cobalt/posix/clock.c | 57 +-----------------
5 files changed, 73 insertions(+), 57 deletions(-)
create mode 100644 kernel/cobalt/ipipe/clock.c
diff --git a/include/cobalt/kernel/ipipe/pipeline/clock.h b/include/cobalt/kernel/ipipe/pipeline/clock.h
index c607d9585..eeeae6602 100644
--- a/include/cobalt/kernel/ipipe/pipeline/clock.h
+++ b/include/cobalt/kernel/ipipe/pipeline/clock.h
@@ -7,6 +7,8 @@
#include <linux/ipipe_tickdev.h>
+struct timespec;
+
static inline u64 pipeline_read_cycle_counter(void)
{
u64 t;
@@ -29,4 +31,6 @@ static inline const char *pipeline_clock_name(void)
return ipipe_clock_name();
}
+int pipeline_get_host_time(struct timespec *tp);
+
#endif /* !_COBALT_KERNEL_IPIPE_CLOCK_H */
diff --git a/include/cobalt/uapi/kernel/vdso.h b/include/cobalt/uapi/kernel/vdso.h
index 396594bb0..5b9b1b66b 100644
--- a/include/cobalt/uapi/kernel/vdso.h
+++ b/include/cobalt/uapi/kernel/vdso.h
@@ -20,6 +20,11 @@
#include <cobalt/uapi/kernel/urw.h>
+/*
+ * I-pipe only. Dovetail enables the common vDSO for getting
+ * CLOCK_REALTIME timestamps from the out-of-band stage
+ * (XNVDSO_FEAT_HOST_REALTIME is cleared in this case).
+ */
struct xnvdso_hostrt_data {
__u64 wall_sec;
__u64 wtom_sec;
diff --git a/kernel/cobalt/ipipe/Makefile b/kernel/cobalt/ipipe/Makefile
index eae6a4a7c..f2b877d45 100644
--- a/kernel/cobalt/ipipe/Makefile
+++ b/kernel/cobalt/ipipe/Makefile
@@ -2,4 +2,4 @@ ccflags-y += -I$(srctree)/kernel
obj-y += pipeline.o
-pipeline-y := init.o intr.o kevents.o tick.o syscall.o sched.o
+pipeline-y := init.o intr.o kevents.o tick.o syscall.o sched.o clock.o
diff --git a/kernel/cobalt/ipipe/clock.c b/kernel/cobalt/ipipe/clock.c
new file mode 100644
index 000000000..d0135dc7a
--- /dev/null
+++ b/kernel/cobalt/ipipe/clock.c
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Written by Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>.
+ */
+
+#include <cobalt/kernel/clock.h>
+#include <cobalt/kernel/vdso.h>
+
+int pipeline_get_host_time(struct timespec *tp)
+{
+#ifdef CONFIG_IPIPE_HAVE_HOSTRT
+ struct xnvdso_hostrt_data *hostrt_data;
+ u64 now, base, mask, cycle_delta;
+ __u32 mult, shift;
+ unsigned long rem;
+ urwstate_t tmp;
+ __u64 nsec;
+
+ hostrt_data = get_hostrt_data();
+ BUG_ON(!hostrt_data);
+
+ if (unlikely(!hostrt_data->live))
+ return -1;
+
+ /*
+ * Note: Disabling HW interrupts around writes to hostrt_data
+ * ensures that a reader (on the Xenomai side) cannot
+ * interrupt a writer (on the Linux kernel side) on the same
+ * CPU. The urw block is required when a reader is
+ * interleaved by a writer on a different CPU. This follows
+ * the approach from userland, where taking the spinlock is
+ * not possible.
+ */
+ unsynced_read_block(&tmp, &hostrt_data->lock) {
+ now = xnclock_read_raw(&nkclock);
+ base = hostrt_data->cycle_last;
+ mask = hostrt_data->mask;
+ mult = hostrt_data->mult;
+ shift = hostrt_data->shift;
+ tp->tv_sec = hostrt_data->wall_sec;
+ nsec = hostrt_data->wall_nsec;
+ }
+
+ /*
+ * At this point, we have a consistent copy of the fundamental
+ * data structure - calculate the interval between the current
+ * and base time stamp cycles, and convert the difference
+ * to nanoseconds.
+ */
+ cycle_delta = (now - base) & mask;
+ nsec += (cycle_delta * mult) >> shift;
+
+ /* Convert to the desired sec, usec representation */
+ tp->tv_sec += xnclock_divrem_billion(nsec, &rem);
+ tp->tv_nsec = rem;
+
+ return 0;
+#else
+ return -EINVAL;
+#endif
+}
diff --git a/kernel/cobalt/posix/clock.c b/kernel/cobalt/posix/clock.c
index 40271f3ed..e957dd956 100644
--- a/kernel/cobalt/posix/clock.c
+++ b/kernel/cobalt/posix/clock.c
@@ -18,7 +18,6 @@
#include <linux/clocksource.h>
#include <linux/bitmap.h>
-#include <cobalt/kernel/vdso.h>
#include <cobalt/kernel/clock.h>
#include "internal.h"
#include "thread.h"
@@ -29,60 +28,6 @@ static struct xnclock *external_clocks[COBALT_MAX_EXTCLOCKS];
DECLARE_BITMAP(cobalt_clock_extids, COBALT_MAX_EXTCLOCKS);
-static int do_clock_host_realtime(struct timespec *tp)
-{
-#ifdef CONFIG_IPIPE_HAVE_HOSTRT
- struct xnvdso_hostrt_data *hostrt_data;
- u64 now, base, mask, cycle_delta;
- __u32 mult, shift;
- unsigned long rem;
- urwstate_t tmp;
- __u64 nsec;
-
- hostrt_data = get_hostrt_data();
- BUG_ON(!hostrt_data);
-
- if (unlikely(!hostrt_data->live))
- return -1;
-
- /*
- * Note: Disabling HW interrupts around writes to hostrt_data
- * ensures that a reader (on the Xenomai side) cannot
- * interrupt a writer (on the Linux kernel side) on the same
- * CPU. The urw block is required when a reader is
- * interleaved by a writer on a different CPU. This follows
- * the approach from userland, where taking the spinlock is
- * not possible.
- */
- unsynced_read_block(&tmp, &hostrt_data->lock) {
- now = xnclock_read_raw(&nkclock);
- base = hostrt_data->cycle_last;
- mask = hostrt_data->mask;
- mult = hostrt_data->mult;
- shift = hostrt_data->shift;
- tp->tv_sec = hostrt_data->wall_sec;
- nsec = hostrt_data->wall_nsec;
- }
-
- /*
- * At this point, we have a consistent copy of the fundamental
- * data structure - calculate the interval between the current
- * and base time stamp cycles, and convert the difference
- * to nanoseconds.
- */
- cycle_delta = (now - base) & mask;
- nsec += (cycle_delta * mult) >> shift;
-
- /* Convert to the desired sec, usec representation */
- tp->tv_sec += xnclock_divrem_billion(nsec, &rem);
- tp->tv_nsec = rem;
-
- return 0;
-#else
- return -EINVAL;
-#endif
-}
-
#define do_ext_clock(__clock_id, __handler, __ret, __args...) \
({ \
struct xnclock *__clock; \
@@ -161,7 +106,7 @@ int __cobalt_clock_gettime(clockid_t clock_id, struct timespec *ts)
ns2ts(ts, xnclock_read_monotonic(&nkclock));
break;
case CLOCK_HOST_REALTIME:
- if (do_clock_host_realtime(ts) != 0)
+ if (pipeline_get_host_time(ts) != 0)
return -EINVAL;
break;
default:
--
2.26.2
next prev parent reply other threads:[~2021-01-31 14:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-31 14:45 [PATCH 01/13] cobalt/kernel: pipeline: abstract context switching support Philippe Gerum
2021-01-31 14:45 ` [PATCH 02/13] cobalt/thread: pipeline: abstract synchronous single-stepping code Philippe Gerum
2021-01-31 14:45 ` Philippe Gerum [this message]
2021-01-31 14:45 ` [PATCH 04/13] cobalt/arch: pipeline: move architecture code to pipeline-specific section Philippe Gerum
2021-02-03 10:18 ` Jan Kiszka
2021-01-31 14:45 ` [PATCH 05/13] cobalt/clock: pipeline: move TSC-related code to the I-pipe section Philippe Gerum
2021-01-31 14:45 ` [PATCH 06/13] cobalt/clock: drop timer calibration Philippe Gerum
2021-02-01 18:14 ` Jan Kiszka
2021-02-02 16:26 ` Philippe Gerum
2021-01-31 14:45 ` [PATCH 07/13] cobalt/arm: ipipe: remove obsolete calibration handler Philippe Gerum
2021-01-31 14:45 ` [PATCH 08/13] cobalt/arm64: " Philippe Gerum
2021-01-31 14:45 ` [PATCH 09/13] cobalt/x86: " Philippe Gerum
2021-01-31 14:45 ` [PATCH 10/13] cobalt/powerpc: " Philippe Gerum
2021-01-31 14:45 ` [PATCH 11/13] cobalt/machine: ipipe: drop timer frequency setting Philippe Gerum
2021-01-31 14:45 ` [PATCH 12/13] cobalt/init: ipipe: remove clock frequency override Philippe Gerum
2021-01-31 14:45 ` [PATCH 13/13] cobalt/assert: pipeline: add TODO() marker Philippe Gerum
2021-02-01 18:20 ` Jan Kiszka
2021-02-02 16:17 ` Philippe Gerum
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