ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 209 insertions, 0 deletions

diff --git a/drivers/regulator/isl9305.c b/drivers/regulator/isl9305.c
new file mode 100644
index 000000000..ec6bd6bb9
--- /dev/null
+++ b/drivers/regulator/isl9305.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * isl9305 - Intersil ISL9305 DCDC regulator
+ *
+ * Copyright 2014 Linaro Ltd
+ *
+ * Author: Mark Brown <broonie@kernel.org>
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/platform_data/isl9305.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/slab.h>
+
+/*
+ * Registers
+ */
+#define ISL9305_DCD1OUT          0x0
+#define ISL9305_DCD2OUT          0x1
+#define ISL9305_LDO1OUT          0x2
+#define ISL9305_LDO2OUT          0x3
+#define ISL9305_DCD_PARAMETER    0x4
+#define ISL9305_SYSTEM_PARAMETER 0x5
+#define ISL9305_DCD_SRCTL        0x6
+
+#define ISL9305_MAX_REG ISL9305_DCD_SRCTL
+
+/*
+ * DCD_PARAMETER
+ */
+#define ISL9305_DCD_PHASE   0x40
+#define ISL9305_DCD2_ULTRA  0x20
+#define ISL9305_DCD1_ULTRA  0x10
+#define ISL9305_DCD2_BLD    0x08
+#define ISL9305_DCD1_BLD    0x04
+#define ISL9305_DCD2_MODE   0x02
+#define ISL9305_DCD1_MODE   0x01
+
+/*
+ * SYSTEM_PARAMETER
+ */
+#define ISL9305_I2C_EN      0x40
+#define ISL9305_DCDPOR_MASK 0x30
+#define ISL9305_LDO2_EN     0x08
+#define ISL9305_LDO1_EN     0x04
+#define ISL9305_DCD2_EN     0x02
+#define ISL9305_DCD1_EN     0x01
+
+/*
+ * DCD_SRCTL
+ */
+#define ISL9305_DCD2SR_MASK 0xc0
+#define ISL9305_DCD1SR_MASK 0x07
+
+static const struct regulator_ops isl9305_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.list_voltage = regulator_list_voltage_linear,
+	.get_voltage_sel = regulator_get_voltage_sel_regmap,
+	.set_voltage_sel = regulator_set_voltage_sel_regmap,
+};
+
+static const struct regulator_desc isl9305_regulators[] = {
+	[ISL9305_DCD1] = {
+		.name =		"DCD1",
+		.of_match =	of_match_ptr("dcd1"),
+		.regulators_node = of_match_ptr("regulators"),
+		.n_voltages =	0x70,
+		.min_uV =	825000,
+		.uV_step =	25000,
+		.vsel_reg =	ISL9305_DCD1OUT,
+		.vsel_mask =	0x7f,
+		.enable_reg =	ISL9305_SYSTEM_PARAMETER,
+		.enable_mask =	ISL9305_DCD1_EN,
+		.supply_name =	"VINDCD1",
+		.ops =		&isl9305_ops,
+		.owner =	THIS_MODULE,
+	},
+	[ISL9305_DCD2] = {
+		.name =		"DCD2",
+		.of_match =	of_match_ptr("dcd2"),
+		.regulators_node = of_match_ptr("regulators"),
+		.n_voltages =	0x70,
+		.min_uV =	825000,
+		.uV_step =	25000,
+		.vsel_reg =	ISL9305_DCD2OUT,
+		.vsel_mask =	0x7f,
+		.enable_reg =	ISL9305_SYSTEM_PARAMETER,
+		.enable_mask =	ISL9305_DCD2_EN,
+		.supply_name =	"VINDCD2",
+		.ops =		&isl9305_ops,
+		.owner =	THIS_MODULE,
+	},
+	[ISL9305_LDO1] = {
+		.name =		"LDO1",
+		.of_match =	of_match_ptr("ldo1"),
+		.regulators_node = of_match_ptr("regulators"),
+		.n_voltages =	0x37,
+		.min_uV =	900000,
+		.uV_step =	50000,
+		.vsel_reg =	ISL9305_LDO1OUT,
+		.vsel_mask =	0x3f,
+		.enable_reg =	ISL9305_SYSTEM_PARAMETER,
+		.enable_mask =	ISL9305_LDO1_EN,
+		.supply_name =	"VINLDO1",
+		.ops =		&isl9305_ops,
+		.owner =	THIS_MODULE,
+	},
+	[ISL9305_LDO2] = {
+		.name =		"LDO2",
+		.of_match =	of_match_ptr("ldo2"),
+		.regulators_node = of_match_ptr("regulators"),
+		.n_voltages =	0x37,
+		.min_uV =	900000,
+		.uV_step =	50000,
+		.vsel_reg =	ISL9305_LDO2OUT,
+		.vsel_mask =	0x3f,
+		.enable_reg =	ISL9305_SYSTEM_PARAMETER,
+		.enable_mask =	ISL9305_LDO2_EN,
+		.supply_name =	"VINLDO2",
+		.ops =		&isl9305_ops,
+		.owner =	THIS_MODULE,
+	},
+};
+
+static const struct regmap_config isl9305_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = ISL9305_MAX_REG,
+	.cache_type = REGCACHE_MAPLE,
+};
+
+static int isl9305_i2c_probe(struct i2c_client *i2c)
+{
+	struct regulator_config config = { };
+	struct isl9305_pdata *pdata = i2c->dev.platform_data;
+	struct regulator_dev *rdev;
+	struct regmap *regmap;
+	int i, ret;
+
+	regmap = devm_regmap_init_i2c(i2c, &isl9305_regmap);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		dev_err(&i2c->dev, "Failed to create regmap: %d\n", ret);
+		return ret;
+	}
+
+	config.dev = &i2c->dev;
+
+	for (i = 0; i < ARRAY_SIZE(isl9305_regulators); i++) {
+		if (pdata)
+			config.init_data = pdata->init_data[i];
+		else
+			config.init_data = NULL;
+
+		rdev = devm_regulator_register(&i2c->dev,
+					       &isl9305_regulators[i],
+					       &config);
+		if (IS_ERR(rdev)) {
+			ret = PTR_ERR(rdev);
+			dev_err(&i2c->dev, "Failed to register %s: %d\n",
+				isl9305_regulators[i].name, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id isl9305_dt_ids[] = {
+	{ .compatible = "isl,isl9305" }, /* for backward compat., don't use */
+	{ .compatible = "isil,isl9305" },
+	{ .compatible = "isl,isl9305h" }, /* for backward compat., don't use */
+	{ .compatible = "isil,isl9305h" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, isl9305_dt_ids);
+#endif
+
+static const struct i2c_device_id isl9305_i2c_id[] = {
+	{ .name = "isl9305" },
+	{ .name = "isl9305h" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, isl9305_i2c_id);
+
+static struct i2c_driver isl9305_regulator_driver = {
+	.driver = {
+		.name = "isl9305",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.of_match_table	= of_match_ptr(isl9305_dt_ids),
+	},
+	.probe = isl9305_i2c_probe,
+	.id_table = isl9305_i2c_id,
+};
+
+module_i2c_driver(isl9305_regulator_driver);
+
+MODULE_AUTHOR("Mark Brown");
+MODULE_DESCRIPTION("Intersil ISL9305 DCDC regulator");
+MODULE_LICENSE("GPL");