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, 144 insertions, 0 deletions

diff --git a/sound/soc/codecs/wcd-common.c b/sound/soc/codecs/wcd-common.c
new file mode 100644
index 000000000..9016e9745
--- /dev/null
+++ b/sound/soc/codecs/wcd-common.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025, Qualcomm Technologies, Inc. and/or its subsidiaries.
+
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/component.h>
+#include <linux/pm_runtime.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_type.h>
+#include <linux/regmap.h>
+
+#include "wcd-common.h"
+
+#define WCD_MIN_MICBIAS_MV	1000
+#define WCD_DEF_MICBIAS_MV	1800
+#define WCD_MAX_MICBIAS_MV	2850
+
+#define SWRS_SCP_HOST_CLK_DIV2_CTL_BANK(m) (0xE0 + 0x10 * (m))
+
+int wcd_get_micb_vout_ctl_val(struct device *dev, u32 micb_mv)
+{
+	/* min micbias voltage is 1V and maximum is 2.85V */
+	if (micb_mv < WCD_MIN_MICBIAS_MV || micb_mv > WCD_MAX_MICBIAS_MV) {
+		dev_err(dev, "Unsupported micbias voltage (%u mV)\n", micb_mv);
+		return -EINVAL;
+	}
+
+	return (micb_mv - WCD_MIN_MICBIAS_MV) / 50;
+}
+EXPORT_SYMBOL_GPL(wcd_get_micb_vout_ctl_val);
+
+static int wcd_get_micbias_val(struct device *dev, int micb_num, u32 *micb_mv)
+{
+	char micbias[64];
+	int mv;
+
+	sprintf(micbias, "qcom,micbias%d-microvolt", micb_num);
+
+	if (of_property_read_u32(dev->of_node, micbias, &mv)) {
+		dev_err(dev, "%s value not found, using default\n", micbias);
+		mv = WCD_DEF_MICBIAS_MV;
+	} else {
+		/* convert it to milli volts */
+		mv = mv/1000;
+	}
+	if (micb_mv)
+		*micb_mv = mv;
+
+	mv = wcd_get_micb_vout_ctl_val(dev, mv);
+	if (mv < 0) {
+		dev_err(dev, "Unsupported %s voltage (%d mV), falling back to default (%d mV)\n",
+				micbias, mv, WCD_DEF_MICBIAS_MV);
+		return wcd_get_micb_vout_ctl_val(dev, WCD_DEF_MICBIAS_MV);
+	}
+
+	return mv;
+}
+
+int wcd_dt_parse_micbias_info(struct wcd_common *common)
+{
+	int ret, i;
+
+	for (i = 0; i < common->max_bias; i++) {
+		ret = wcd_get_micbias_val(common->dev, i + 1, &common->micb_mv[i]);
+		if (ret < 0)
+			return ret;
+		common->micb_vout[i] = ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wcd_dt_parse_micbias_info);
+
+static int wcd_sdw_component_bind(struct device *dev, struct device *master, void *data)
+{
+	pm_runtime_set_autosuspend_delay(dev, 3000);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static void wcd_sdw_component_unbind(struct device *dev, struct device *master, void *data)
+{
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_dont_use_autosuspend(dev);
+}
+
+const struct component_ops wcd_sdw_component_ops = {
+	.bind = wcd_sdw_component_bind,
+	.unbind = wcd_sdw_component_unbind,
+};
+EXPORT_SYMBOL_GPL(wcd_sdw_component_ops);
+
+int wcd_update_status(struct sdw_slave *slave, enum sdw_slave_status status)
+{
+	struct regmap *regmap = dev_get_regmap(&slave->dev, NULL);
+
+	if (regmap && status == SDW_SLAVE_ATTACHED) {
+		/* Write out any cached changes that happened between probe and attach */
+		regcache_cache_only(regmap, false);
+		return regcache_sync(regmap);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wcd_update_status);
+
+int wcd_bus_config(struct sdw_slave *slave, struct sdw_bus_params *params)
+{
+	sdw_write(slave, SWRS_SCP_HOST_CLK_DIV2_CTL_BANK(params->next_bank), 0x01);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wcd_bus_config);
+
+int wcd_interrupt_callback(struct sdw_slave *slave, struct irq_domain *slave_irq,
+		unsigned int wcd_intr_status0, unsigned int wcd_intr_status1,
+		unsigned int wcd_intr_status2)
+{
+	struct regmap *regmap = dev_get_regmap(&slave->dev, NULL);
+	u32 sts1, sts2, sts3;
+
+	do {
+		handle_nested_irq(irq_find_mapping(slave_irq, 0));
+		regmap_read(regmap, wcd_intr_status0, &sts1);
+		regmap_read(regmap, wcd_intr_status1, &sts2);
+		regmap_read(regmap, wcd_intr_status2, &sts3);
+
+	} while (sts1 || sts2 || sts3);
+
+	return IRQ_HANDLED;
+}
+EXPORT_SYMBOL_GPL(wcd_interrupt_callback);
+
+MODULE_DESCRIPTION("Common Qualcomm WCD Codec helpers driver");
+MODULE_LICENSE("GPL");