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, 212 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-meson6.c b/drivers/clocksource/timer-meson6.c
new file mode 100644
index 000000000..99f5510a2
--- /dev/null
+++ b/drivers/clocksource/timer-meson6.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Amlogic Meson6 SoCs timer handling.
+ *
+ * Copyright (C) 2014 Carlo Caione <carlo@caione.org>
+ *
+ * Based on code from Amlogic, Inc
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqreturn.h>
+#include <linux/sched_clock.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#ifdef CONFIG_ARM
+#include <linux/delay.h>
+#endif
+
+#define MESON_ISA_TIMER_MUX					0x00
+#define MESON_ISA_TIMER_MUX_TIMERD_EN				BIT(19)
+#define MESON_ISA_TIMER_MUX_TIMERC_EN				BIT(18)
+#define MESON_ISA_TIMER_MUX_TIMERB_EN				BIT(17)
+#define MESON_ISA_TIMER_MUX_TIMERA_EN				BIT(16)
+#define MESON_ISA_TIMER_MUX_TIMERD_MODE				BIT(15)
+#define MESON_ISA_TIMER_MUX_TIMERC_MODE				BIT(14)
+#define MESON_ISA_TIMER_MUX_TIMERB_MODE				BIT(13)
+#define MESON_ISA_TIMER_MUX_TIMERA_MODE				BIT(12)
+#define MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_MASK		GENMASK(10, 8)
+#define MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_SYSTEM_CLOCK	0x0
+#define MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_1US		0x1
+#define MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_10US		0x2
+#define MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_100US		0x3
+#define MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_1MS		0x4
+#define MESON_ISA_TIMER_MUX_TIMERD_INPUT_CLOCK_MASK		GENMASK(7, 6)
+#define MESON_ISA_TIMER_MUX_TIMERC_INPUT_CLOCK_MASK		GENMASK(5, 4)
+#define MESON_ISA_TIMER_MUX_TIMERB_INPUT_CLOCK_MASK		GENMASK(3, 2)
+#define MESON_ISA_TIMER_MUX_TIMERA_INPUT_CLOCK_MASK		GENMASK(1, 0)
+#define MESON_ISA_TIMER_MUX_TIMERABCD_INPUT_CLOCK_1US		0x0
+#define MESON_ISA_TIMER_MUX_TIMERABCD_INPUT_CLOCK_10US		0x1
+#define MESON_ISA_TIMER_MUX_TIMERABCD_INPUT_CLOCK_100US		0x0
+#define MESON_ISA_TIMER_MUX_TIMERABCD_INPUT_CLOCK_1MS		0x3
+
+#define MESON_ISA_TIMERA					0x04
+#define MESON_ISA_TIMERB					0x08
+#define MESON_ISA_TIMERC					0x0c
+#define MESON_ISA_TIMERD					0x10
+#define MESON_ISA_TIMERE					0x14
+
+static void __iomem *timer_base;
+
+#ifdef CONFIG_ARM
+static unsigned long meson6_read_current_timer(void)
+{
+	return readl_relaxed(timer_base + MESON_ISA_TIMERE);
+}
+
+static struct delay_timer meson6_delay_timer = {
+	.read_current_timer = meson6_read_current_timer,
+	.freq = 1000 * 1000,
+};
+#endif
+
+static u64 notrace meson6_timer_sched_read(void)
+{
+	return (u64)readl(timer_base + MESON_ISA_TIMERE);
+}
+
+static void meson6_clkevt_time_stop(void)
+{
+	u32 val = readl(timer_base + MESON_ISA_TIMER_MUX);
+
+	writel(val & ~MESON_ISA_TIMER_MUX_TIMERA_EN,
+	       timer_base + MESON_ISA_TIMER_MUX);
+}
+
+static void meson6_clkevt_time_setup(unsigned long delay)
+{
+	writel(delay, timer_base + MESON_ISA_TIMERA);
+}
+
+static void meson6_clkevt_time_start(bool periodic)
+{
+	u32 val = readl(timer_base + MESON_ISA_TIMER_MUX);
+
+	if (periodic)
+		val |= MESON_ISA_TIMER_MUX_TIMERA_MODE;
+	else
+		val &= ~MESON_ISA_TIMER_MUX_TIMERA_MODE;
+
+	writel(val | MESON_ISA_TIMER_MUX_TIMERA_EN,
+	       timer_base + MESON_ISA_TIMER_MUX);
+}
+
+static int meson6_shutdown(struct clock_event_device *evt)
+{
+	meson6_clkevt_time_stop();
+	return 0;
+}
+
+static int meson6_set_oneshot(struct clock_event_device *evt)
+{
+	meson6_clkevt_time_stop();
+	meson6_clkevt_time_start(false);
+	return 0;
+}
+
+static int meson6_set_periodic(struct clock_event_device *evt)
+{
+	meson6_clkevt_time_stop();
+	meson6_clkevt_time_setup(USEC_PER_SEC / HZ - 1);
+	meson6_clkevt_time_start(true);
+	return 0;
+}
+
+static int meson6_clkevt_next_event(unsigned long evt,
+				    struct clock_event_device *unused)
+{
+	meson6_clkevt_time_stop();
+	meson6_clkevt_time_setup(evt);
+	meson6_clkevt_time_start(false);
+
+	return 0;
+}
+
+static struct clock_event_device meson6_clockevent = {
+	.name			= "meson6_tick",
+	.rating			= 400,
+	.features		= CLOCK_EVT_FEAT_PERIODIC |
+				  CLOCK_EVT_FEAT_ONESHOT,
+	.set_state_shutdown	= meson6_shutdown,
+	.set_state_periodic	= meson6_set_periodic,
+	.set_state_oneshot	= meson6_set_oneshot,
+	.tick_resume		= meson6_shutdown,
+	.set_next_event		= meson6_clkevt_next_event,
+};
+
+static irqreturn_t meson6_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static int __init meson6_timer_init(struct device_node *node)
+{
+	u32 val;
+	int ret, irq;
+
+	timer_base = of_io_request_and_map(node, 0, "meson6-timer");
+	if (IS_ERR(timer_base)) {
+		pr_err("Can't map registers\n");
+		return -ENXIO;
+	}
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (irq <= 0) {
+		pr_err("Can't parse IRQ\n");
+		return -EINVAL;
+	}
+
+	/* Set 1us for timer E */
+	val = readl(timer_base + MESON_ISA_TIMER_MUX);
+	val &= ~MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_MASK;
+	val |= FIELD_PREP(MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_MASK,
+			  MESON_ISA_TIMER_MUX_TIMERE_INPUT_CLOCK_1US);
+	writel(val, timer_base + MESON_ISA_TIMER_MUX);
+
+	sched_clock_register(meson6_timer_sched_read, 32, USEC_PER_SEC);
+	clocksource_mmio_init(timer_base + MESON_ISA_TIMERE, node->name,
+			      1000 * 1000, 300, 32, clocksource_mmio_readl_up);
+
+	/* Timer A base 1us */
+	val &= ~MESON_ISA_TIMER_MUX_TIMERA_INPUT_CLOCK_MASK;
+	val |= FIELD_PREP(MESON_ISA_TIMER_MUX_TIMERA_INPUT_CLOCK_MASK,
+			  MESON_ISA_TIMER_MUX_TIMERABCD_INPUT_CLOCK_1US);
+	writel(val, timer_base + MESON_ISA_TIMER_MUX);
+
+	/* Stop the timer A */
+	meson6_clkevt_time_stop();
+
+	ret = request_irq(irq, meson6_timer_interrupt,
+			  IRQF_TIMER | IRQF_IRQPOLL, "meson6_timer",
+			  &meson6_clockevent);
+	if (ret) {
+		pr_warn("failed to setup irq %d\n", irq);
+		return ret;
+	}
+
+	meson6_clockevent.cpumask = cpu_possible_mask;
+	meson6_clockevent.irq = irq;
+
+	clockevents_config_and_register(&meson6_clockevent, USEC_PER_SEC,
+					1, 0xfffe);
+
+#ifdef CONFIG_ARM
+	/* Also use MESON_ISA_TIMERE for delays */
+	register_current_timer_delay(&meson6_delay_timer);
+#endif
+
+	return 0;
+}
+TIMER_OF_DECLARE(meson6, "amlogic,meson6-timer",
+		       meson6_timer_init);