Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.

1 files changed, 207 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-goldfish.c b/drivers/rtc/rtc-goldfish.c
new file mode 100644
index 000000000..53ec7173c
--- /dev/null
+++ b/drivers/rtc/rtc-goldfish.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0
+/* drivers/rtc/rtc-goldfish.c
+ *
+ * Copyright (C) 2007 Google, Inc.
+ * Copyright (C) 2017 Imagination Technologies Ltd.
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/goldfish.h>
+#include <clocksource/timer-goldfish.h>
+
+struct goldfish_rtc {
+	void __iomem *base;
+	int irq;
+	struct rtc_device *rtc;
+};
+
+static int goldfish_rtc_read_alarm(struct device *dev,
+				   struct rtc_wkalrm *alrm)
+{
+	u64 rtc_alarm;
+	u64 rtc_alarm_low;
+	u64 rtc_alarm_high;
+	void __iomem *base;
+	struct goldfish_rtc *rtcdrv;
+
+	rtcdrv = dev_get_drvdata(dev);
+	base = rtcdrv->base;
+
+	rtc_alarm_low = gf_ioread32(base + TIMER_ALARM_LOW);
+	rtc_alarm_high = gf_ioread32(base + TIMER_ALARM_HIGH);
+	rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
+
+	do_div(rtc_alarm, NSEC_PER_SEC);
+	memset(alrm, 0, sizeof(struct rtc_wkalrm));
+
+	rtc_time64_to_tm(rtc_alarm, &alrm->time);
+
+	if (gf_ioread32(base + TIMER_ALARM_STATUS))
+		alrm->enabled = 1;
+	else
+		alrm->enabled = 0;
+
+	return 0;
+}
+
+static int goldfish_rtc_set_alarm(struct device *dev,
+				  struct rtc_wkalrm *alrm)
+{
+	struct goldfish_rtc *rtcdrv;
+	u64 rtc_alarm64;
+	u64 rtc_status_reg;
+	void __iomem *base;
+
+	rtcdrv = dev_get_drvdata(dev);
+	base = rtcdrv->base;
+
+	if (alrm->enabled) {
+		rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
+		gf_iowrite32((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
+		gf_iowrite32(rtc_alarm64, base + TIMER_ALARM_LOW);
+		gf_iowrite32(1, base + TIMER_IRQ_ENABLED);
+	} else {
+		/*
+		 * if this function was called with enabled=0
+		 * then it could mean that the application is
+		 * trying to cancel an ongoing alarm
+		 */
+		rtc_status_reg = gf_ioread32(base + TIMER_ALARM_STATUS);
+		if (rtc_status_reg)
+			gf_iowrite32(1, base + TIMER_CLEAR_ALARM);
+	}
+
+	return 0;
+}
+
+static int goldfish_rtc_alarm_irq_enable(struct device *dev,
+					 unsigned int enabled)
+{
+	void __iomem *base;
+	struct goldfish_rtc *rtcdrv;
+
+	rtcdrv = dev_get_drvdata(dev);
+	base = rtcdrv->base;
+
+	if (enabled)
+		gf_iowrite32(1, base + TIMER_IRQ_ENABLED);
+	else
+		gf_iowrite32(0, base + TIMER_IRQ_ENABLED);
+
+	return 0;
+}
+
+static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
+{
+	struct goldfish_rtc *rtcdrv = dev_id;
+	void __iomem *base = rtcdrv->base;
+
+	gf_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);
+
+	rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
+
+	return IRQ_HANDLED;
+}
+
+static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct goldfish_rtc *rtcdrv;
+	void __iomem *base;
+	u64 time_high;
+	u64 time_low;
+	u64 time;
+
+	rtcdrv = dev_get_drvdata(dev);
+	base = rtcdrv->base;
+
+	time_low = gf_ioread32(base + TIMER_TIME_LOW);
+	time_high = gf_ioread32(base + TIMER_TIME_HIGH);
+	time = (time_high << 32) | time_low;
+
+	do_div(time, NSEC_PER_SEC);
+
+	rtc_time64_to_tm(time, tm);
+
+	return 0;
+}
+
+static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct goldfish_rtc *rtcdrv;
+	void __iomem *base;
+	u64 now64;
+
+	rtcdrv = dev_get_drvdata(dev);
+	base = rtcdrv->base;
+
+	now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
+	gf_iowrite32((now64 >> 32), base + TIMER_TIME_HIGH);
+	gf_iowrite32(now64, base + TIMER_TIME_LOW);
+
+	return 0;
+}
+
+static const struct rtc_class_ops goldfish_rtc_ops = {
+	.read_time	= goldfish_rtc_read_time,
+	.set_time	= goldfish_rtc_set_time,
+	.read_alarm	= goldfish_rtc_read_alarm,
+	.set_alarm	= goldfish_rtc_set_alarm,
+	.alarm_irq_enable = goldfish_rtc_alarm_irq_enable
+};
+
+static int goldfish_rtc_probe(struct platform_device *pdev)
+{
+	struct goldfish_rtc *rtcdrv;
+	int err;
+
+	rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
+	if (!rtcdrv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rtcdrv);
+	rtcdrv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rtcdrv->base))
+		return PTR_ERR(rtcdrv->base);
+
+	rtcdrv->irq = platform_get_irq(pdev, 0);
+	if (rtcdrv->irq < 0)
+		return -ENODEV;
+
+	rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtcdrv->rtc))
+		return PTR_ERR(rtcdrv->rtc);
+
+	rtcdrv->rtc->ops = &goldfish_rtc_ops;
+	rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
+
+	err = devm_request_irq(&pdev->dev, rtcdrv->irq,
+			       goldfish_rtc_interrupt,
+			       0, pdev->name, rtcdrv);
+	if (err)
+		return err;
+
+	return devm_rtc_register_device(rtcdrv->rtc);
+}
+
+static const struct of_device_id goldfish_rtc_of_match[] = {
+	{ .compatible = "google,goldfish-rtc", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
+
+static struct platform_driver goldfish_rtc = {
+	.probe = goldfish_rtc_probe,
+	.driver = {
+		.name = "goldfish_rtc",
+		.of_match_table = goldfish_rtc_of_match,
+	}
+};
+
+module_platform_driver(goldfish_rtc);
+
+MODULE_DESCRIPTION("Android Goldfish Real Time Clock driver");
+MODULE_LICENSE("GPL v2");