From bdab18633a302c82b5e5d5dbc4e38b0baf9c0837 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sun, 20 Sep 2026 08:15:23 -0700
Subject: Merge tag 'locking-urgent-2026-09-20' of
 git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull futex fix from Ingo Molnar:

 - Also allocate a default private futex hash on vfork() as well, to
   avoid races with (private) futex waiters (Peter Zijlstra)

* tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Also allocate private hash on vfork()
---
 drivers/base/regmap/regmap-ram.c | 91 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 drivers/base/regmap/regmap-ram.c

(limited to 'drivers/base/regmap/regmap-ram.c')

diff --git a/drivers/base/regmap/regmap-ram.c b/drivers/base/regmap/regmap-ram.c
new file mode 100644
index 000000000..c7356b0d8
--- /dev/null
+++ b/drivers/base/regmap/regmap-ram.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Register map access API - Memory region
+//
+// This is intended for testing only
+//
+// Copyright (c) 2023, Arm Ltd
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/swab.h>
+
+#include "internal.h"
+
+static int regmap_ram_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct regmap_ram_data *data = context;
+
+	data->vals[reg] = val;
+	data->written[reg] = true;
+
+	return 0;
+}
+
+static int regmap_ram_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct regmap_ram_data *data = context;
+
+	*val = data->vals[reg];
+	data->read[reg] = true;
+
+	return 0;
+}
+
+static void regmap_ram_free_context(void *context)
+{
+	struct regmap_ram_data *data = context;
+
+	kfree(data->vals);
+	kfree(data->read);
+	kfree(data->written);
+	kfree(data);
+}
+
+static const struct regmap_bus regmap_ram = {
+	.fast_io = true,
+	.reg_write = regmap_ram_write,
+	.reg_read = regmap_ram_read,
+	.free_context = regmap_ram_free_context,
+};
+
+struct regmap *__regmap_init_ram(struct device *dev,
+				 const struct regmap_config *config,
+				 struct regmap_ram_data *data,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name)
+{
+	struct regmap *map;
+
+	if (!config->max_register) {
+		pr_crit("No max_register specified for RAM regmap\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	data->read = kzalloc_objs(bool, config->max_register + 1);
+	if (!data->read)
+		return ERR_PTR(-ENOMEM);
+
+	data->written = kzalloc_objs(bool, config->max_register + 1);
+	if (!data->written) {
+		kfree(data->read);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	map = __regmap_init(dev, &regmap_ram, data, config,
+			    lock_key, lock_name);
+	if (IS_ERR(map)) {
+		kfree(data->read);
+		kfree(data->written);
+	}
+
+	return map;
+}
+EXPORT_SYMBOL_GPL(__regmap_init_ram);
+
+MODULE_DESCRIPTION("Register map access API - Memory region");
+MODULE_LICENSE("GPL v2");
-- 
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