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2023-12-08 01573e231f18eb2d99162747186f59511f56b64d 
 kernel/kernel/time/clocksource.c
....@@ -1,26 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0+
12 /*
2
- * linux/kernel/time/clocksource.c
3
- *
43  * This file contains the functions which manage clocksource drivers.
54  *
65  * Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2 of the License, or
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- * (at your option) any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program; if not, write to the Free Software
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- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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- *
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- * TODO WishList:
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- *   o Allow clocksource drivers to be unregistered
246  */
257 
268 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
....@@ -123,12 +105,12 @@
123105 static int watchdog_running;
124106 static atomic_t watchdog_reset_pending;
125107 
126
-static void inline clocksource_watchdog_lock(unsigned long *flags)
108
+static inline void clocksource_watchdog_lock(unsigned long *flags)
127109 {
128110 	spin_lock_irqsave(&watchdog_lock, *flags);
129111 }
130112 
131
-static void inline clocksource_watchdog_unlock(unsigned long *flags)
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+static inline void clocksource_watchdog_unlock(unsigned long *flags)
132114 {
133115 	spin_unlock_irqrestore(&watchdog_lock, *flags);
134116 }
....@@ -240,6 +222,60 @@
240222 	pr_warn("timekeeping watchdog on CPU%d: %s read-back delay of %lldns, attempt %d, marking unstable\n",
241223 		smp_processor_id(), watchdog->name, wd_delay, nretries);
242224 	return false;
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+}
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+
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+static u64 csnow_mid;
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+static cpumask_t cpus_ahead;
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+static cpumask_t cpus_behind;
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+
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+static void clocksource_verify_one_cpu(void *csin)
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+{
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+	struct clocksource *cs = (struct clocksource *)csin;
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+
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+	csnow_mid = cs->read(cs);
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+}
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+
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+static void clocksource_verify_percpu(struct clocksource *cs)
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+{
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+	int64_t cs_nsec, cs_nsec_max = 0, cs_nsec_min = LLONG_MAX;
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+	u64 csnow_begin, csnow_end;
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+	int cpu, testcpu;
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+	s64 delta;
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+
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+	cpumask_clear(&cpus_ahead);
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+	cpumask_clear(&cpus_behind);
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+	preempt_disable();
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+	testcpu = smp_processor_id();
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+	pr_warn("Checking clocksource %s synchronization from CPU %d.\n", cs->name, testcpu);
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+	for_each_online_cpu(cpu) {
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+		if (cpu == testcpu)
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+			continue;
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+		csnow_begin = cs->read(cs);
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+		smp_call_function_single(cpu, clocksource_verify_one_cpu, cs, 1);
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+		csnow_end = cs->read(cs);
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+		delta = (s64)((csnow_mid - csnow_begin) & cs->mask);
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+		if (delta < 0)
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+			cpumask_set_cpu(cpu, &cpus_behind);
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+		delta = (csnow_end - csnow_mid) & cs->mask;
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+		if (delta < 0)
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+			cpumask_set_cpu(cpu, &cpus_ahead);
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+		delta = clocksource_delta(csnow_end, csnow_begin, cs->mask);
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+		cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift);
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+		if (cs_nsec > cs_nsec_max)
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+			cs_nsec_max = cs_nsec;
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+		if (cs_nsec < cs_nsec_min)
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+			cs_nsec_min = cs_nsec;
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+	}
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+	preempt_enable();
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+	if (!cpumask_empty(&cpus_ahead))
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+		pr_warn("        CPUs %*pbl ahead of CPU %d for clocksource %s.\n",
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+			cpumask_pr_args(&cpus_ahead), testcpu, cs->name);
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+	if (!cpumask_empty(&cpus_behind))
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+		pr_warn("        CPUs %*pbl behind CPU %d for clocksource %s.\n",
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+			cpumask_pr_args(&cpus_behind), testcpu, cs->name);
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+	if (!cpumask_empty(&cpus_ahead) || !cpumask_empty(&cpus_behind))
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+		pr_warn("        CPU %d check durations %lldns - %lldns for clocksource %s.\n",
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+			testcpu, cs_nsec_min, cs_nsec_max, cs->name);
243279 }
244280 
245281 static void clocksource_watchdog(struct timer_list *unused)
....@@ -465,6 +501,12 @@
465501 	struct clocksource *cs, *tmp;
466502 	unsigned long flags;
467503 	int select = 0;
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+
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+	/* Do any required per-CPU skew verification. */
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+	if (curr_clocksource &&
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+	    curr_clocksource->flags & CLOCK_SOURCE_UNSTABLE &&
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+	    curr_clocksource->flags & CLOCK_SOURCE_VERIFY_PERCPU)
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+		clocksource_verify_percpu(curr_clocksource);
468510 
469511 	spin_lock_irqsave(&watchdog_lock, flags);
470512 	list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
....@@ -883,11 +925,7 @@
883925 	mutex_unlock(&clocksource_mutex);
884926 	return 0;
885927 }
886
-#ifdef CONFIG_ROCKCHIP_THUNDER_BOOT
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-pure_initcall(clocksource_done_booting);
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-#else
889928 fs_initcall(clocksource_done_booting);
890
-#endif
891929 
892930 /*
893931  * Enqueue the clocksource sorted by rating
....@@ -989,6 +1027,15 @@
9891027 {
9901028 	unsigned long flags;
9911029 
1030
+	clocksource_arch_init(cs);
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+
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+	if (cs->vdso_clock_mode < 0 ||
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+	    cs->vdso_clock_mode >= VDSO_CLOCKMODE_MAX) {
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+		pr_warn("clocksource %s registered with invalid VDSO mode %d. Disabling VDSO support.\n",
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+			cs->name, cs->vdso_clock_mode);
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+		cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
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+	}
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+
9921039 	/* Initialize mult/shift and max_idle_ns */
9931040 	__clocksource_update_freq_scale(cs, scale, freq);
9941041