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, 330 insertions, 0 deletions

diff --git a/drivers/regulator/mpq7920.c b/drivers/regulator/mpq7920.c
new file mode 100644
index 000000000..0cbc17deb
--- /dev/null
+++ b/drivers/regulator/mpq7920.c
@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// mpq7920.c  - regulator driver for mps mpq7920
+//
+// Copyright 2019 Monolithic Power Systems, Inc
+//
+// Author: Saravanan Sekar <sravanhome@gmail.com>
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include "mpq7920.h"
+
+#define MPQ7920_BUCK_VOLT_RANGE \
+	((MPQ7920_VOLT_MAX - MPQ7920_BUCK_VOLT_MIN)/MPQ7920_VOLT_STEP + 1)
+#define MPQ7920_LDO_VOLT_RANGE \
+	((MPQ7920_VOLT_MAX - MPQ7920_LDO_VOLT_MIN)/MPQ7920_VOLT_STEP + 1)
+
+#define MPQ7920BUCK(_name, _id, _ilim)					\
+	[MPQ7920_BUCK ## _id] = {					\
+		.id = MPQ7920_BUCK ## _id,				\
+		.name = _name,						\
+		.of_match = _name,					\
+		.regulators_node = "regulators",			\
+		.of_parse_cb = mpq7920_parse_cb,			\
+		.ops = &mpq7920_buck_ops,				\
+		.min_uV = MPQ7920_BUCK_VOLT_MIN,			\
+		.uV_step = MPQ7920_VOLT_STEP,				\
+		.n_voltages = MPQ7920_BUCK_VOLT_RANGE,			\
+		.curr_table = _ilim,					\
+		.n_current_limits = ARRAY_SIZE(_ilim),			\
+		.csel_reg = MPQ7920_BUCK ##_id## _REG_C,		\
+		.csel_mask = MPQ7920_MASK_BUCK_ILIM,			\
+		.enable_reg = MPQ7920_REG_REGULATOR_EN,			\
+		.enable_mask = BIT(MPQ7920_REGULATOR_EN_OFFSET -	\
+					 MPQ7920_BUCK ## _id),		\
+		.vsel_reg = MPQ7920_BUCK ##_id## _REG_A,		\
+		.vsel_mask = MPQ7920_MASK_VREF,				\
+		.active_discharge_on	= MPQ7920_DISCHARGE_ON,		\
+		.active_discharge_reg	= MPQ7920_BUCK ##_id## _REG_B,	\
+		.active_discharge_mask	= MPQ7920_MASK_DISCHARGE,	\
+		.soft_start_reg		= MPQ7920_BUCK ##_id## _REG_C,	\
+		.soft_start_mask	= MPQ7920_MASK_SOFTSTART,	\
+		.owner			= THIS_MODULE,			\
+	}
+
+#define MPQ7920LDO(_name, _id, _ops, _ilim, _ilim_sz, _creg, _cmask)	\
+	[MPQ7920_LDO ## _id] = {					\
+		.id = MPQ7920_LDO ## _id,				\
+		.name = _name,						\
+		.of_match = _name,					\
+		.regulators_node = "regulators",			\
+		.ops = _ops,						\
+		.min_uV = MPQ7920_LDO_VOLT_MIN,				\
+		.uV_step = MPQ7920_VOLT_STEP,				\
+		.n_voltages = MPQ7920_LDO_VOLT_RANGE,			\
+		.vsel_reg = MPQ7920_LDO ##_id## _REG_A,			\
+		.vsel_mask = MPQ7920_MASK_VREF,				\
+		.curr_table = _ilim,					\
+		.n_current_limits = _ilim_sz,				\
+		.csel_reg = _creg,					\
+		.csel_mask = _cmask,					\
+		.enable_reg = (_id == 1) ? 0 : MPQ7920_REG_REGULATOR_EN,\
+		.enable_mask = BIT(MPQ7920_REGULATOR_EN_OFFSET -	\
+					MPQ7920_LDO ##_id + 1),		\
+		.active_discharge_on	= MPQ7920_DISCHARGE_ON,		\
+		.active_discharge_mask	= MPQ7920_MASK_DISCHARGE,	\
+		.active_discharge_reg	= MPQ7920_LDO ##_id## _REG_B,	\
+		.type			= REGULATOR_VOLTAGE,		\
+		.owner			= THIS_MODULE,			\
+	}
+
+enum mpq7920_regulators {
+	MPQ7920_BUCK1,
+	MPQ7920_BUCK2,
+	MPQ7920_BUCK3,
+	MPQ7920_BUCK4,
+	MPQ7920_LDO1, /* LDORTC */
+	MPQ7920_LDO2,
+	MPQ7920_LDO3,
+	MPQ7920_LDO4,
+	MPQ7920_LDO5,
+	MPQ7920_MAX_REGULATORS,
+};
+
+struct mpq7920_regulator_info {
+	struct regmap *regmap;
+	struct regulator_desc *rdesc;
+};
+
+static const struct regmap_config mpq7920_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x25,
+};
+
+/* Current limits array (in uA)
+ * ILIM1 & ILIM3
+ */
+static const unsigned int mpq7920_I_limits1[] = {
+	4600000, 6600000, 7600000, 9300000
+};
+
+/* ILIM2 & ILIM4 */
+static const unsigned int mpq7920_I_limits2[] = {
+	2700000, 3900000, 5100000, 6100000
+};
+
+/* LDO4 & LDO5 */
+static const unsigned int mpq7920_I_limits3[] = {
+	300000, 700000
+};
+
+static int mpq7920_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay);
+static int mpq7920_parse_cb(struct device_node *np,
+				const struct regulator_desc *rdesc,
+				struct regulator_config *config);
+
+/* RTCLDO not controllable, always ON */
+static const struct regulator_ops mpq7920_ldortc_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+};
+
+static const struct regulator_ops mpq7920_ldo_wo_current_ops = {
+	.enable			= regulator_enable_regmap,
+	.disable		= regulator_disable_regmap,
+	.is_enabled		= regulator_is_enabled_regmap,
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.set_active_discharge	= regulator_set_active_discharge_regmap,
+};
+
+static const struct regulator_ops mpq7920_ldo_ops = {
+	.enable			= regulator_enable_regmap,
+	.disable		= regulator_disable_regmap,
+	.is_enabled		= regulator_is_enabled_regmap,
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.set_active_discharge	= regulator_set_active_discharge_regmap,
+	.get_current_limit	= regulator_get_current_limit_regmap,
+	.set_current_limit	= regulator_set_current_limit_regmap,
+};
+
+static const struct regulator_ops mpq7920_buck_ops = {
+	.enable			= regulator_enable_regmap,
+	.disable		= regulator_disable_regmap,
+	.is_enabled		= regulator_is_enabled_regmap,
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.set_active_discharge	= regulator_set_active_discharge_regmap,
+	.set_soft_start		= regulator_set_soft_start_regmap,
+	.set_ramp_delay		= mpq7920_set_ramp_delay,
+};
+
+static struct regulator_desc mpq7920_regulators_desc[MPQ7920_MAX_REGULATORS] = {
+	MPQ7920BUCK("buck1", 1, mpq7920_I_limits1),
+	MPQ7920BUCK("buck2", 2, mpq7920_I_limits2),
+	MPQ7920BUCK("buck3", 3, mpq7920_I_limits1),
+	MPQ7920BUCK("buck4", 4, mpq7920_I_limits2),
+	MPQ7920LDO("ldortc", 1, &mpq7920_ldortc_ops, NULL, 0, 0, 0),
+	MPQ7920LDO("ldo2", 2, &mpq7920_ldo_wo_current_ops, NULL, 0, 0, 0),
+	MPQ7920LDO("ldo3", 3, &mpq7920_ldo_wo_current_ops, NULL, 0, 0, 0),
+	MPQ7920LDO("ldo4", 4, &mpq7920_ldo_ops, mpq7920_I_limits3,
+			ARRAY_SIZE(mpq7920_I_limits3), MPQ7920_LDO4_REG_B,
+			MPQ7920_MASK_LDO_ILIM),
+	MPQ7920LDO("ldo5", 5, &mpq7920_ldo_ops, mpq7920_I_limits3,
+			ARRAY_SIZE(mpq7920_I_limits3), MPQ7920_LDO5_REG_B,
+			MPQ7920_MASK_LDO_ILIM),
+};
+
+/*
+ * DVS ramp rate BUCK1 to BUCK4
+ * 00-01: Reserved
+ * 10: 8mV/us
+ * 11: 4mV/us
+ */
+static int mpq7920_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
+{
+	unsigned int ramp_val;
+
+	if (ramp_delay > 8000 || ramp_delay < 0)
+		return -EINVAL;
+
+	if (ramp_delay <= 4000)
+		ramp_val = 3;
+	else
+		ramp_val = 2;
+
+	return regmap_update_bits(rdev->regmap, MPQ7920_REG_CTL0,
+				  MPQ7920_MASK_DVS_SLEWRATE, ramp_val << 6);
+}
+
+static int mpq7920_parse_cb(struct device_node *np,
+				const struct regulator_desc *desc,
+				struct regulator_config *config)
+{
+	uint8_t val;
+	int ret;
+	struct mpq7920_regulator_info *info = config->driver_data;
+	struct regulator_desc *rdesc = &info->rdesc[desc->id];
+
+	if (of_property_read_bool(np, "mps,buck-ovp-disable")) {
+		regmap_update_bits(config->regmap,
+				MPQ7920_BUCK1_REG_B + (rdesc->id * 4),
+				MPQ7920_MASK_OVP, MPQ7920_OVP_DISABLE);
+	}
+
+	ret = of_property_read_u8(np, "mps,buck-phase-delay", &val);
+	if (!ret) {
+		regmap_update_bits(config->regmap,
+				MPQ7920_BUCK1_REG_C + (rdesc->id * 4),
+				MPQ7920_MASK_BUCK_PHASE_DEALY,
+				(val & 3) << 4);
+	}
+
+	ret = of_property_read_u8(np, "mps,buck-softstart", &val);
+	if (!ret)
+		rdesc->soft_start_val_on = (val & 3) << 2;
+
+	return 0;
+}
+
+static void mpq7920_parse_dt(struct device *dev,
+		 struct mpq7920_regulator_info *info)
+{
+	int ret;
+	struct device_node *np = dev->of_node;
+	uint8_t freq;
+
+	np = of_get_child_by_name(np, "regulators");
+	if (!np) {
+		dev_err(dev, "missing 'regulators' subnode in DT\n");
+		return;
+	}
+
+	ret = of_property_read_u8(np, "mps,switch-freq", &freq);
+	if (!ret) {
+		regmap_update_bits(info->regmap, MPQ7920_REG_CTL0,
+					MPQ7920_MASK_SWITCH_FREQ,
+					(freq & 3) << 4);
+	}
+
+	of_node_put(np);
+}
+
+static int mpq7920_i2c_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct mpq7920_regulator_info *info;
+	struct regulator_config config = { NULL, };
+	struct regulator_dev *rdev;
+	struct regmap *regmap;
+	int i;
+
+	info = devm_kzalloc(dev, sizeof(struct mpq7920_regulator_info),
+				GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->rdesc = mpq7920_regulators_desc;
+	regmap = devm_regmap_init_i2c(client, &mpq7920_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(dev, "Failed to allocate regmap!\n");
+		return PTR_ERR(regmap);
+	}
+
+	i2c_set_clientdata(client, info);
+	info->regmap = regmap;
+	if (client->dev.of_node)
+		mpq7920_parse_dt(&client->dev, info);
+
+	config.dev = dev;
+	config.regmap = regmap;
+	config.driver_data = info;
+
+	for (i = 0; i < MPQ7920_MAX_REGULATORS; i++) {
+		rdev = devm_regulator_register(dev,
+					       &mpq7920_regulators_desc[i],
+					       &config);
+		if (IS_ERR(rdev)) {
+			dev_err(dev, "Failed to register regulator!\n");
+			return PTR_ERR(rdev);
+		}
+	}
+
+	return 0;
+}
+
+static const struct of_device_id mpq7920_of_match[] = {
+	{ .compatible = "mps,mpq7920"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, mpq7920_of_match);
+
+static const struct i2c_device_id mpq7920_id[] = {
+	{ .name = "mpq7920" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mpq7920_id);
+
+static struct i2c_driver mpq7920_regulator_driver = {
+	.driver = {
+		.name = "mpq7920",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.of_match_table = mpq7920_of_match,
+	},
+	.probe = mpq7920_i2c_probe,
+	.id_table = mpq7920_id,
+};
+module_i2c_driver(mpq7920_regulator_driver);
+
+MODULE_AUTHOR("Saravanan Sekar <sravanhome@gmail.com>");
+MODULE_DESCRIPTION("MPQ7920 PMIC regulator driver");
+MODULE_LICENSE("GPL");