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, 217 insertions, 0 deletions

diff --git a/drivers/cache/ax45mp_cache.c b/drivers/cache/ax45mp_cache.c
new file mode 100644
index 000000000..934c5087e
--- /dev/null
+++ b/drivers/cache/ax45mp_cache.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * non-coherent cache functions for Andes AX45MP
+ *
+ * Copyright (C) 2023 Renesas Electronics Corp.
+ */
+
+#include <linux/cacheflush.h>
+#include <linux/cacheinfo.h>
+#include <linux/dma-direction.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#include <asm/dma-noncoherent.h>
+
+/* L2 cache registers */
+#define AX45MP_L2C_REG_CTL_OFFSET		0x8
+
+#define AX45MP_L2C_REG_C0_CMD_OFFSET		0x40
+#define AX45MP_L2C_REG_C0_ACC_OFFSET		0x48
+#define AX45MP_L2C_REG_STATUS_OFFSET		0x80
+
+/* D-cache operation */
+#define AX45MP_CCTL_L1D_VA_INVAL		0 /* Invalidate an L1 cache entry */
+#define AX45MP_CCTL_L1D_VA_WB			1 /* Write-back an L1 cache entry */
+
+/* L2 CCTL status */
+#define AX45MP_CCTL_L2_STATUS_IDLE		0
+
+/* L2 CCTL status cores mask */
+#define AX45MP_CCTL_L2_STATUS_C0_MASK		0xf
+
+/* L2 cache operation */
+#define AX45MP_CCTL_L2_PA_INVAL			0x8 /* Invalidate an L2 cache entry */
+#define AX45MP_CCTL_L2_PA_WB			0x9 /* Write-back an L2 cache entry */
+
+#define AX45MP_L2C_REG_PER_CORE_OFFSET		0x10
+#define AX45MP_CCTL_L2_STATUS_PER_CORE_OFFSET	4
+
+#define AX45MP_L2C_REG_CN_CMD_OFFSET(n)	\
+	(AX45MP_L2C_REG_C0_CMD_OFFSET + ((n) * AX45MP_L2C_REG_PER_CORE_OFFSET))
+#define AX45MP_L2C_REG_CN_ACC_OFFSET(n)	\
+	(AX45MP_L2C_REG_C0_ACC_OFFSET + ((n) * AX45MP_L2C_REG_PER_CORE_OFFSET))
+#define AX45MP_CCTL_L2_STATUS_CN_MASK(n)	\
+	(AX45MP_CCTL_L2_STATUS_C0_MASK << ((n) * AX45MP_CCTL_L2_STATUS_PER_CORE_OFFSET))
+
+#define AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM	0x80b
+#define AX45MP_CCTL_REG_UCCTLCOMMAND_NUM	0x80c
+
+#define AX45MP_CACHE_LINE_SIZE			64
+
+struct ax45mp_priv {
+	void __iomem *l2c_base;
+	u32 ax45mp_cache_line_size;
+};
+
+static struct ax45mp_priv ax45mp_priv;
+
+/* L2 Cache operations */
+static inline uint32_t ax45mp_cpu_l2c_get_cctl_status(void)
+{
+	return readl(ax45mp_priv.l2c_base + AX45MP_L2C_REG_STATUS_OFFSET);
+}
+
+static void ax45mp_cpu_cache_operation(unsigned long start, unsigned long end,
+				       unsigned int l1_op, unsigned int l2_op)
+{
+	unsigned long line_size = ax45mp_priv.ax45mp_cache_line_size;
+	void __iomem *base = ax45mp_priv.l2c_base;
+	int mhartid = smp_processor_id();
+	unsigned long pa;
+
+	while (end > start) {
+		csr_write(AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM, start);
+		csr_write(AX45MP_CCTL_REG_UCCTLCOMMAND_NUM, l1_op);
+
+		pa = virt_to_phys((void *)start);
+		writel(pa, base + AX45MP_L2C_REG_CN_ACC_OFFSET(mhartid));
+		writel(l2_op, base + AX45MP_L2C_REG_CN_CMD_OFFSET(mhartid));
+		while ((ax45mp_cpu_l2c_get_cctl_status() &
+			AX45MP_CCTL_L2_STATUS_CN_MASK(mhartid)) !=
+			AX45MP_CCTL_L2_STATUS_IDLE)
+			;
+
+		start += line_size;
+	}
+}
+
+/* Write-back L1 and L2 cache entry */
+static inline void ax45mp_cpu_dcache_wb_range(unsigned long start, unsigned long end)
+{
+	ax45mp_cpu_cache_operation(start, end, AX45MP_CCTL_L1D_VA_WB,
+				   AX45MP_CCTL_L2_PA_WB);
+}
+
+/* Invalidate the L1 and L2 cache entry */
+static inline void ax45mp_cpu_dcache_inval_range(unsigned long start, unsigned long end)
+{
+	ax45mp_cpu_cache_operation(start, end, AX45MP_CCTL_L1D_VA_INVAL,
+				   AX45MP_CCTL_L2_PA_INVAL);
+}
+
+static void ax45mp_dma_cache_inv(phys_addr_t paddr, size_t size)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+	unsigned long end = start + size;
+	unsigned long line_size;
+	unsigned long flags;
+
+	if (unlikely(start == end))
+		return;
+
+	line_size = ax45mp_priv.ax45mp_cache_line_size;
+
+	start = start & (~(line_size - 1));
+	end = ((end + line_size - 1) & (~(line_size - 1)));
+
+	local_irq_save(flags);
+
+	ax45mp_cpu_dcache_inval_range(start, end);
+
+	local_irq_restore(flags);
+}
+
+static void ax45mp_dma_cache_wback(phys_addr_t paddr, size_t size)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+	unsigned long end = start + size;
+	unsigned long line_size;
+	unsigned long flags;
+
+	if (unlikely(start == end))
+		return;
+
+	line_size = ax45mp_priv.ax45mp_cache_line_size;
+	start = start & (~(line_size - 1));
+	end = ((end + line_size - 1) & (~(line_size - 1)));
+	local_irq_save(flags);
+	ax45mp_cpu_dcache_wb_range(start, end);
+	local_irq_restore(flags);
+}
+
+static void ax45mp_dma_cache_wback_inv(phys_addr_t paddr, size_t size)
+{
+	ax45mp_dma_cache_wback(paddr, size);
+	ax45mp_dma_cache_inv(paddr, size);
+}
+
+static int ax45mp_get_l2_line_size(struct device_node *np)
+{
+	int ret;
+
+	ret = of_property_read_u32(np, "cache-line-size", &ax45mp_priv.ax45mp_cache_line_size);
+	if (ret) {
+		pr_err("Failed to get cache-line-size, defaulting to 64 bytes\n");
+		return ret;
+	}
+
+	if (ax45mp_priv.ax45mp_cache_line_size != AX45MP_CACHE_LINE_SIZE) {
+		pr_err("Expected cache-line-size to be 64 bytes (found:%u)\n",
+		       ax45mp_priv.ax45mp_cache_line_size);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct riscv_nonstd_cache_ops ax45mp_cmo_ops __initdata = {
+	.wback = &ax45mp_dma_cache_wback,
+	.inv = &ax45mp_dma_cache_inv,
+	.wback_inv = &ax45mp_dma_cache_wback_inv,
+};
+
+static const struct of_device_id ax45mp_cache_ids[] = {
+	{ .compatible = "andestech,ax45mp-cache" },
+	{ /* sentinel */ }
+};
+
+static int __init ax45mp_cache_init(void)
+{
+	struct resource res;
+	int ret;
+
+	struct device_node *np __free(device_node) =
+		of_find_matching_node(NULL, ax45mp_cache_ids);
+	if (!of_device_is_available(np))
+		return -ENODEV;
+
+	ret = of_address_to_resource(np, 0, &res);
+	if (ret)
+		return ret;
+
+	/*
+	 * If IOCP is present on the Andes AX45MP core riscv_cbom_block_size
+	 * will be 0 for sure, so we can definitely rely on it. If
+	 * riscv_cbom_block_size = 0 we don't need to handle CMO using SW any
+	 * more so we just return success here and only if its being set we
+	 * continue further in the probe path.
+	 */
+	if (!riscv_cbom_block_size)
+		return 0;
+
+	ax45mp_priv.l2c_base = ioremap(res.start, resource_size(&res));
+	if (!ax45mp_priv.l2c_base)
+		return -ENOMEM;
+
+	ret = ax45mp_get_l2_line_size(np);
+	if (ret) {
+		iounmap(ax45mp_priv.l2c_base);
+		return ret;
+	}
+
+	riscv_noncoherent_register_cache_ops(&ax45mp_cmo_ops);
+
+	return 0;
+}
+early_initcall(ax45mp_cache_init);