209 lines
7.4 KiB
Diff
209 lines
7.4 KiB
Diff
commit 513c7457865dba262a43e03fbe9178f4b08ba319
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Author: Miroslav Lichvar <mlichvar@redhat.com>
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Date: Mon Oct 24 15:25:30 2022 +0200
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Drop support for old kernels returning zero frequency.
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Kernels before 3.10 had a bug in reading of the system clock frequency,
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which was worked around by commit da347d7a36f2 ("ptp4l: Set clock
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frequency on start").
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Drop this workaround and support for the old kernels to make
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clockadj_get_freq() useful.
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(Rebased to 3.1.1)
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Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
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diff --git a/clock.c b/clock.c
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index f3df220..9079428 100644
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--- a/clock.c
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+++ b/clock.c
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@@ -1147,11 +1147,6 @@ struct clock *clock_create(enum clock_type type, struct config *config,
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if (c->clkid != CLOCK_INVALID) {
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fadj = (int) clockadj_get_freq(c->clkid);
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- /* Due to a bug in older kernels, the reading may silently fail
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- and return 0. Set the frequency back to make sure fadj is
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- the actual frequency of the clock. */
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- clockadj_set_freq(c->clkid, fadj);
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-
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/* Disable write phase mode if not implemented by driver */
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if (c->write_phase_mode && !phc_has_writephase(c->clkid)) {
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pr_err("clock does not support write phase mode");
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@@ -1746,7 +1741,6 @@ int clock_switch_phc(struct clock *c, int phc_index)
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return -1;
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}
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fadj = (int) clockadj_get_freq(clkid);
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- clockadj_set_freq(clkid, fadj);
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servo = servo_create(c->config, c->servo_type, -fadj, max_adj, 0);
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if (!servo) {
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pr_err("Switching PHC, failed to create clock servo");
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diff --git a/phc2sys.c b/phc2sys.c
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index 5f6fbaa..af948eb 100644
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--- a/phc2sys.c
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+++ b/phc2sys.c
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@@ -147,9 +147,6 @@ static struct servo *servo_add(struct phc2sys_private *priv,
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clockadj_init(clock->clkid);
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ppb = clockadj_get_freq(clock->clkid);
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- /* The reading may silently fail and return 0, reset the frequency to
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- make sure ppb is the actual frequency of the clock. */
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- clockadj_set_freq(clock->clkid, ppb);
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if (clock->clkid == CLOCK_REALTIME) {
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sysclk_set_leap(0);
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max_ppb = sysclk_max_freq();
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diff --git a/ts2phc_slave.c b/ts2phc_slave.c
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index 749efe5..5541d91 100644
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--- a/ts2phc_slave.c
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+++ b/ts2phc_slave.c
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@@ -183,10 +183,6 @@ static struct ts2phc_slave *ts2phc_slave_create(struct config *cfg, const char *
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pr_debug("PHC slave %s has ptp index %d", device, junk);
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fadj = (int) clockadj_get_freq(slave->clk);
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- /* Due to a bug in older kernels, the reading may silently fail
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- and return 0. Set the frequency back to make sure fadj is
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- the actual frequency of the clock. */
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- clockadj_set_freq(slave->clk, fadj);
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max_adj = phc_max_adj(slave->clk);
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commit 80d6875b0072c7ea636a5631e590fa72d169c351
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Author: Miroslav Lichvar <mlichvar@redhat.com>
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Date: Mon Oct 24 15:25:31 2022 +0200
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Don't accept errors in clockadj_get_freq().
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Exit if an error is returned from the clock_adjtime() call in
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clockadj_get_freq(). No recoverable errors are expected.
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Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
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diff --git a/clockadj.c b/clockadj.c
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index 957dc57..4c920b9 100644
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--- a/clockadj.c
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+++ b/clockadj.c
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@@ -19,6 +19,7 @@
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#include <errno.h>
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#include <math.h>
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+#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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@@ -72,6 +73,7 @@ double clockadj_get_freq(clockid_t clkid)
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memset(&tx, 0, sizeof(tx));
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if (clock_adjtime(clkid, &tx) < 0) {
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pr_err("failed to read out the clock frequency adjustment: %m");
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+ exit(1);
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} else {
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f = tx.freq / 65.536;
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if (clkid == CLOCK_REALTIME && realtime_nominal_tick && tx.tick)
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commit 211cbfe810ef4082d1af8e9b50f65d4f6fd7246a
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Author: Miroslav Lichvar <mlichvar@redhat.com>
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Date: Mon Oct 24 15:25:32 2022 +0200
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Extend clockcheck to check for changes in frequency.
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Before setting the new frequency offset on a clock update, compare the
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current frequency returned by the kernel with the value saved from the
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previous update. Print a warning message if the difference is larger
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than 1 ppb, allowing for rounding errors in conversion to and from
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double. The kernel caches the value set by clock_adjtime() in shifted
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ppm, it doesn't request it from the driver, which can have a lower
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resulution.
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This should detect misconfigurations where multiple processes are trying
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to control the clock (e.g. another ptp4l/phc2sys instance or an NTP
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client), even when they don't step the clock.
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Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
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diff --git a/clock.c b/clock.c
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index 9079428..eea7983 100644
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--- a/clock.c
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+++ b/clock.c
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@@ -1760,6 +1760,9 @@ int clock_switch_phc(struct clock *c, int phc_index)
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static void clock_synchronize_locked(struct clock *c, double adj)
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{
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+ if (c->sanity_check) {
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+ clockcheck_freq(c->sanity_check, clockadj_get_freq(c->clkid));
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+ }
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clockadj_set_freq(c->clkid, -adj);
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if (c->clkid == CLOCK_REALTIME) {
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sysclk_set_sync();
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diff --git a/clockcheck.c b/clockcheck.c
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index f0141be..b5a69cc 100644
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--- a/clockcheck.c
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+++ b/clockcheck.c
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@@ -123,6 +123,16 @@ void clockcheck_set_freq(struct clockcheck *cc, int freq)
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cc->freq_known = 1;
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}
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+int clockcheck_freq(struct clockcheck *cc, int freq)
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+{
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+ /* Allow difference of 1 ppb due to conversion to/from double */
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+ if (cc->freq_known && abs(cc->current_freq - freq) > 1) {
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+ pr_warning("clockcheck: clock frequency changed unexpectedly!");
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+ return 1;
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+ }
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+ return 0;
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+}
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+
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void clockcheck_step(struct clockcheck *cc, int64_t step)
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{
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if (cc->last_ts)
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diff --git a/clockcheck.h b/clockcheck.h
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index 1ff86eb..4b09b98 100644
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--- a/clockcheck.h
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+++ b/clockcheck.h
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@@ -54,6 +54,14 @@ int clockcheck_sample(struct clockcheck *cc, uint64_t ts);
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*/
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void clockcheck_set_freq(struct clockcheck *cc, int freq);
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+/**
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+ * Check whether the frequency correction did not change unexpectedly.
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+ * @param cc Pointer to a clock check obtained via @ref clockcheck_create().
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+ * @param freq Current reading of the frequency correction in ppb.
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+ * @return Zero if the frequency did not change, non-zero otherwise.
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+ */
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+int clockcheck_freq(struct clockcheck *cc, int freq);
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+
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/**
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* Inform clock check that the clock was stepped.
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* @param cc Pointer to a clock check obtained via @ref clockcheck_create().
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diff --git a/phc2sys.c b/phc2sys.c
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index af948eb..4daa1bf 100644
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--- a/phc2sys.c
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+++ b/phc2sys.c
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@@ -566,6 +566,9 @@ static void update_clock(struct phc2sys_private *priv, struct clock *clock,
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/* Fall through. */
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case SERVO_LOCKED:
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case SERVO_LOCKED_STABLE:
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+ if (clock->sanity_check)
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+ clockcheck_freq(clock->sanity_check,
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+ clockadj_get_freq(clock->clkid));
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clockadj_set_freq(clock->clkid, -ppb);
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if (clock->clkid == CLOCK_REALTIME)
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sysclk_set_sync();
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diff --git a/ptp4l.8 b/ptp4l.8
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index 4917240..f760e2b 100644
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--- a/ptp4l.8
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+++ b/ptp4l.8
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@@ -605,8 +605,10 @@ This option used to be called
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The maximum allowed frequency offset between uncorrected clock and the system
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monotonic clock in parts per billion (ppb). This is used as a sanity check of
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the synchronized clock. When a larger offset is measured, a warning message
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-will be printed and the servo will be reset. When set to 0, the sanity check is
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-disabled. The default is 200000000 (20%).
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+will be printed and the servo will be reset. If the frequency correction set by
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+ptp4l changes unexpectedly between updates of the clock (e.g. due to another
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+process trying to control the clock), a warning message will be printed. When
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+set to 0, the sanity check is disabled. The default is 200000000 (20%).
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.TP
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.B initial_delay
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The initial path delay of the clock in nanoseconds used for synchronization of
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