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, 206 insertions, 0 deletions

diff --git a/drivers/mfd/cs42l43-sdw.c b/drivers/mfd/cs42l43-sdw.c
new file mode 100644
index 000000000..0a6999453
--- /dev/null
+++ b/drivers/mfd/cs42l43-sdw.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CS42L43 SoundWire driver
+ *
+ * Copyright (C) 2022-2023 Cirrus Logic, Inc. and
+ *                         Cirrus Logic International Semiconductor Ltd.
+ */
+
+#include <linux/array_size.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/mfd/cs42l43.h>
+#include <linux/mfd/cs42l43-regs.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_registers.h>
+#include <linux/soundwire/sdw_type.h>
+
+#include "cs42l43.h"
+
+#define CS42L43_SDW_PORT(port, chans) { \
+	.num = port, \
+	.max_ch = chans, \
+	.type = SDW_DPN_FULL, \
+	.max_word = 24, \
+}
+
+static const struct regmap_config cs42l43_sdw_regmap = {
+	.reg_bits		= 32,
+	.reg_stride		= 4,
+	.val_bits		= 32,
+	.reg_format_endian	= REGMAP_ENDIAN_LITTLE,
+	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
+
+	.max_register		= CS42L43_MCU_RAM_MAX,
+	.readable_reg		= cs42l43_readable_register,
+	.volatile_reg		= cs42l43_volatile_register,
+	.precious_reg		= cs42l43_precious_register,
+
+	.cache_type		= REGCACHE_MAPLE,
+	.reg_defaults		= cs42l43_reg_default,
+	.num_reg_defaults	= ARRAY_SIZE(cs42l43_reg_default),
+};
+
+static const struct sdw_dpn_prop cs42l43_src_port_props[] = {
+	CS42L43_SDW_PORT(1, 4),
+	CS42L43_SDW_PORT(2, 2),
+	CS42L43_SDW_PORT(3, 2),
+	CS42L43_SDW_PORT(4, 2),
+};
+
+static const struct sdw_dpn_prop cs42l43_sink_port_props[] = {
+	CS42L43_SDW_PORT(5, 2),
+	CS42L43_SDW_PORT(6, 2),
+	CS42L43_SDW_PORT(7, 2),
+};
+
+static int cs42l43_read_prop(struct sdw_slave *sdw)
+{
+	struct sdw_slave_prop *prop = &sdw->prop;
+	struct device *dev = &sdw->dev;
+	int i;
+
+	prop->use_domain_irq = true;
+	prop->paging_support = true;
+	prop->wake_capable = true;
+	prop->quirks = SDW_SLAVE_QUIRKS_INVALID_INITIAL_PARITY;
+	prop->scp_int1_mask = SDW_SCP_INT1_BUS_CLASH | SDW_SCP_INT1_PARITY |
+			      SDW_SCP_INT1_IMPL_DEF;
+
+	for (i = 0; i < ARRAY_SIZE(cs42l43_src_port_props); i++)
+		prop->source_ports |= BIT(cs42l43_src_port_props[i].num);
+
+	prop->src_dpn_prop = devm_kmemdup(dev, cs42l43_src_port_props,
+					  sizeof(cs42l43_src_port_props), GFP_KERNEL);
+	if (!prop->src_dpn_prop)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(cs42l43_sink_port_props); i++)
+		prop->sink_ports |= BIT(cs42l43_sink_port_props[i].num);
+
+	prop->sink_dpn_prop = devm_kmemdup(dev, cs42l43_sink_port_props,
+					   sizeof(cs42l43_sink_port_props), GFP_KERNEL);
+	if (!prop->sink_dpn_prop)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int cs42l43_sdw_update_status(struct sdw_slave *sdw, enum sdw_slave_status status)
+{
+	struct cs42l43 *cs42l43 = dev_get_drvdata(&sdw->dev);
+
+	switch (status) {
+	case SDW_SLAVE_ATTACHED:
+		dev_dbg(cs42l43->dev, "Device attach\n");
+
+		sdw_write_no_pm(sdw, CS42L43_GEN_INT_MASK_1,
+				CS42L43_INT_STAT_GEN1_MASK);
+		break;
+	case SDW_SLAVE_UNATTACHED:
+		dev_dbg(cs42l43->dev, "Device detach\n");
+
+		complete(&cs42l43->device_detach);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int cs42l43_sdw_interrupt(struct sdw_slave *sdw,
+				 struct sdw_slave_intr_status *status)
+{
+	/*
+	 * The IRQ itself was handled through the regmap_irq handler, this is
+	 * just clearing up the additional Cirrus SoundWire registers that are
+	 * not covered by the SoundWire framework or the IRQ handler itself.
+	 * There is only a single bit in GEN_INT_STAT_1 and it doesn't clear if
+	 * IRQs are still pending so doing a read/write here after handling the
+	 * IRQ is fine.
+	 */
+	sdw_read_no_pm(sdw, CS42L43_GEN_INT_STAT_1);
+	sdw_write_no_pm(sdw, CS42L43_GEN_INT_STAT_1, CS42L43_INT_STAT_GEN1_MASK);
+
+	return 0;
+}
+
+static int cs42l43_sdw_bus_config(struct sdw_slave *sdw,
+				  struct sdw_bus_params *params)
+{
+	struct cs42l43 *cs42l43 = dev_get_drvdata(&sdw->dev);
+	int ret = 0;
+
+	mutex_lock(&cs42l43->pll_lock);
+
+	if (cs42l43->sdw_freq != params->curr_dr_freq / 2) {
+		if (cs42l43->sdw_pll_active) {
+			dev_err(cs42l43->dev,
+				"PLL active can't change SoundWire bus clock\n");
+			ret = -EBUSY;
+		} else {
+			cs42l43->sdw_freq = params->curr_dr_freq / 2;
+		}
+	}
+
+	mutex_unlock(&cs42l43->pll_lock);
+
+	return ret;
+}
+
+static const struct sdw_slave_ops cs42l43_sdw_ops = {
+	.read_prop		= cs42l43_read_prop,
+	.update_status		= cs42l43_sdw_update_status,
+	.interrupt_callback	= cs42l43_sdw_interrupt,
+	.bus_config		= cs42l43_sdw_bus_config,
+};
+
+static int cs42l43_sdw_probe(struct sdw_slave *sdw, const struct sdw_device_id *id)
+{
+	struct cs42l43 *cs42l43;
+	struct device *dev = &sdw->dev;
+
+	cs42l43 = devm_kzalloc(dev, sizeof(*cs42l43), GFP_KERNEL);
+	if (!cs42l43)
+		return -ENOMEM;
+
+	cs42l43->dev = dev;
+	cs42l43->sdw = sdw;
+	cs42l43->variant_id = (long)id->driver_data;
+
+	cs42l43->regmap = devm_regmap_init_sdw(sdw, &cs42l43_sdw_regmap);
+	if (IS_ERR(cs42l43->regmap))
+		return dev_err_probe(cs42l43->dev, PTR_ERR(cs42l43->regmap),
+				     "Failed to allocate regmap\n");
+
+	return cs42l43_dev_probe(cs42l43);
+}
+
+static const struct sdw_device_id cs42l43_sdw_id[] = {
+	SDW_SLAVE_ENTRY(0x01FA, 0x4243, (void *)CS42L43_DEVID_VAL),
+	SDW_SLAVE_ENTRY(0x01FA, 0x2A3B, (void *)CS42L43B_DEVID_VAL),
+	{ }
+};
+MODULE_DEVICE_TABLE(sdw, cs42l43_sdw_id);
+
+static struct sdw_driver cs42l43_sdw_driver = {
+	.driver = {
+		.name		= "cs42l43",
+		.pm		= pm_ptr(&cs42l43_pm_ops),
+	},
+
+	.probe		= cs42l43_sdw_probe,
+	.id_table	= cs42l43_sdw_id,
+	.ops		= &cs42l43_sdw_ops,
+};
+module_sdw_driver(cs42l43_sdw_driver);
+
+MODULE_IMPORT_NS("MFD_CS42L43");
+
+MODULE_DESCRIPTION("CS42L43 SoundWire Driver");
+MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
+MODULE_LICENSE("GPL");