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, 75 insertions, 0 deletions

diff --git a/drivers/misc/ibmasm/lowlevel.c b/drivers/misc/ibmasm/lowlevel.c
new file mode 100644
index 000000000..5313230f3
--- /dev/null
+++ b/drivers/misc/ibmasm/lowlevel.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * IBM ASM Service Processor Device Driver
+ *
+ * Copyright (C) IBM Corporation, 2004
+ *
+ * Author: Max Asböck <amax@us.ibm.com>
+ */
+
+#include "ibmasm.h"
+#include "lowlevel.h"
+#include "i2o.h"
+#include "dot_command.h"
+#include "remote.h"
+
+static struct i2o_header header = I2O_HEADER_TEMPLATE;
+
+
+int ibmasm_send_i2o_message(struct service_processor *sp)
+{
+	u32 mfa;
+	size_t command_size;
+	struct i2o_message *message;
+	struct command *command = sp->current_command;
+
+	command_size = get_dot_command_size(command->buffer);
+	if (command_size > command->buffer_size)
+		return 1;
+	if (command_size > I2O_COMMAND_SIZE)
+		command_size = I2O_COMMAND_SIZE;
+
+	mfa = get_mfa_inbound(sp->base_address);
+	if (!mfa)
+		return 1;
+
+	header.message_size = outgoing_message_size((unsigned int)command_size);
+	message = get_i2o_message(sp->base_address, mfa);
+
+	memcpy_toio(&message->header, &header, sizeof(struct i2o_header));
+	memcpy_toio(&message->data, command->buffer, command_size);
+
+	set_mfa_inbound(sp->base_address, mfa);
+
+	return 0;
+}
+
+irqreturn_t ibmasm_interrupt_handler(int irq, void * dev_id)
+{
+	u32	mfa;
+	struct service_processor *sp = (struct service_processor *)dev_id;
+	void __iomem *base_address = sp->base_address;
+	char tsbuf[32];
+
+	if (!sp_interrupt_pending(base_address))
+		return IRQ_NONE;
+
+	dbg("respond to interrupt at %s\n", get_timestamp(tsbuf));
+
+	if (mouse_interrupt_pending(sp)) {
+		ibmasm_handle_mouse_interrupt(sp);
+		clear_mouse_interrupt(sp);
+	}
+
+	mfa = get_mfa_outbound(base_address);
+	if (valid_mfa(mfa)) {
+		struct i2o_message *msg = get_i2o_message(base_address, mfa);
+		ibmasm_receive_message(sp, &msg->data, incoming_data_size(msg));
+	} else
+		dbg("didn't get a valid MFA\n");
+
+	set_mfa_outbound(base_address, mfa);
+	dbg("finished interrupt at   %s\n", get_timestamp(tsbuf));
+
+	return IRQ_HANDLED;
+}