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>

3 files changed, 325 insertions, 0 deletions

diff --git a/drivers/pmdomain/marvell/Kconfig b/drivers/pmdomain/marvell/Kconfig
new file mode 100644
index 000000000..6c4084c82
--- /dev/null
+++ b/drivers/pmdomain/marvell/Kconfig
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menu "Marvell PM Domains"
+	depends on ARCH_MMP || COMPILE_TEST
+
+config PXA1908_PM_DOMAINS
+	tristate "Marvell PXA1908 power domains"
+	depends on OF
+	depends on PM
+	default y if ARCH_MMP && ARM64
+	select AUXILIARY_BUS
+	select MFD_SYSCON
+	select PM_GENERIC_DOMAINS
+	select PM_GENERIC_DOMAINS_OF
+	help
+	  Say Y here to enable support for Marvell PXA1908's power domanis.
+
+endmenu
diff --git a/drivers/pmdomain/marvell/Makefile b/drivers/pmdomain/marvell/Makefile
new file mode 100644
index 000000000..22c25013f
--- /dev/null
+++ b/drivers/pmdomain/marvell/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_PXA1908_PM_DOMAINS) += pxa1908-power-controller.o
diff --git a/drivers/pmdomain/marvell/pxa1908-power-controller.c b/drivers/pmdomain/marvell/pxa1908-power-controller.c
new file mode 100644
index 000000000..4a957ab0e
--- /dev/null
+++ b/drivers/pmdomain/marvell/pxa1908-power-controller.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 Duje Mihanović <duje@dujemihanovic.xyz>
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/container_of.h>
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/power/marvell,pxa1908-power.h>
+
+/* VPU, GPU, ISP */
+#define APMU_PWR_CTRL_REG	0xd8
+#define APMU_PWR_BLK_TMR_REG	0xdc
+#define APMU_PWR_STATUS_REG	0xf0
+
+/* DSI */
+#define APMU_DEBUG		0x88
+#define DSI_PHY_DVM_MASK	BIT(31)
+
+#define APMU_AUDIO_CLK		0x80
+#define AUDIO_ULCX_ENABLE	0x0d
+
+#define POWER_ON_LATENCY_US	300
+#define POWER_OFF_LATENCY_US	20
+#define POWER_POLL_TIMEOUT_US	(25 * USEC_PER_MSEC)
+#define POWER_POLL_SLEEP_US	6
+
+#define NR_DOMAINS	6
+
+#define to_pxa1908_pd(_genpd) container_of(_genpd, struct pxa1908_pd, genpd)
+
+struct pxa1908_pd_ctrl {
+	struct generic_pm_domain *domains[NR_DOMAINS];
+	struct genpd_onecell_data onecell_data;
+	struct regmap *base;
+	struct device *dev;
+};
+
+struct pxa1908_pd_data {
+	u32 reg_clk_res_ctrl;
+	u32 pwr_state;
+	u32 hw_mode;
+	bool keep_on;
+	int id;
+};
+
+struct pxa1908_pd {
+	const struct pxa1908_pd_data data;
+	struct pxa1908_pd_ctrl *ctrl;
+	struct generic_pm_domain genpd;
+	bool initialized;
+};
+
+static inline bool pxa1908_pd_is_on(struct pxa1908_pd *pd)
+{
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+
+	switch (pd->data.id) {
+	case PXA1908_POWER_DOMAIN_AUDIO:
+		return regmap_test_bits(ctrl->base, APMU_AUDIO_CLK, AUDIO_ULCX_ENABLE);
+	case PXA1908_POWER_DOMAIN_DSI:
+		return regmap_test_bits(ctrl->base, APMU_DEBUG, DSI_PHY_DVM_MASK);
+	default:
+		return regmap_test_bits(ctrl->base, APMU_PWR_STATUS_REG, pd->data.pwr_state);
+	}
+}
+
+static int pxa1908_pd_power_on(struct generic_pm_domain *genpd)
+{
+	struct pxa1908_pd *pd = to_pxa1908_pd(genpd);
+	const struct pxa1908_pd_data *data = &pd->data;
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+	unsigned int status;
+	int ret = 0;
+
+	regmap_set_bits(ctrl->base, data->reg_clk_res_ctrl, data->hw_mode);
+	if (data->id != PXA1908_POWER_DOMAIN_ISP)
+		regmap_write(ctrl->base, APMU_PWR_BLK_TMR_REG, 0x20001fff);
+	regmap_set_bits(ctrl->base, APMU_PWR_CTRL_REG, data->pwr_state);
+
+	ret = regmap_read_poll_timeout(ctrl->base, APMU_PWR_STATUS_REG, status,
+				       status & data->pwr_state, POWER_POLL_SLEEP_US,
+				       POWER_ON_LATENCY_US + POWER_POLL_TIMEOUT_US);
+	if (ret == -ETIMEDOUT)
+		dev_err(ctrl->dev, "timed out powering on domain '%s'\n", pd->genpd.name);
+
+	return ret;
+}
+
+static int pxa1908_pd_power_off(struct generic_pm_domain *genpd)
+{
+	struct pxa1908_pd *pd = to_pxa1908_pd(genpd);
+	const struct pxa1908_pd_data *data = &pd->data;
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+	unsigned int status;
+	int ret;
+
+	regmap_clear_bits(ctrl->base, APMU_PWR_CTRL_REG, data->pwr_state);
+
+	ret = regmap_read_poll_timeout(ctrl->base, APMU_PWR_STATUS_REG, status,
+				       !(status & data->pwr_state), POWER_POLL_SLEEP_US,
+				       POWER_OFF_LATENCY_US + POWER_POLL_TIMEOUT_US);
+	if (ret == -ETIMEDOUT) {
+		dev_err(ctrl->dev, "timed out powering off domain '%s'\n", pd->genpd.name);
+		return ret;
+	}
+
+	return regmap_clear_bits(ctrl->base, data->reg_clk_res_ctrl, data->hw_mode);
+}
+
+static inline int pxa1908_dsi_power_on(struct generic_pm_domain *genpd)
+{
+	struct pxa1908_pd *pd = to_pxa1908_pd(genpd);
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+
+	return regmap_set_bits(ctrl->base, APMU_DEBUG, DSI_PHY_DVM_MASK);
+}
+
+static inline int pxa1908_dsi_power_off(struct generic_pm_domain *genpd)
+{
+	struct pxa1908_pd *pd = to_pxa1908_pd(genpd);
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+
+	return regmap_clear_bits(ctrl->base, APMU_DEBUG, DSI_PHY_DVM_MASK);
+}
+
+static inline int pxa1908_audio_power_on(struct generic_pm_domain *genpd)
+{
+	struct pxa1908_pd *pd = to_pxa1908_pd(genpd);
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+
+	return regmap_set_bits(ctrl->base, APMU_AUDIO_CLK, AUDIO_ULCX_ENABLE);
+}
+
+static inline int pxa1908_audio_power_off(struct generic_pm_domain *genpd)
+{
+	struct pxa1908_pd *pd = to_pxa1908_pd(genpd);
+	struct pxa1908_pd_ctrl *ctrl = pd->ctrl;
+
+	return regmap_clear_bits(ctrl->base, APMU_AUDIO_CLK, AUDIO_ULCX_ENABLE);
+}
+
+#define DOMAIN(_id, _name, ctrl, mode, state) \
+	[_id] = { \
+		.data = { \
+			.reg_clk_res_ctrl = ctrl, \
+			.hw_mode = BIT(mode), \
+			.pwr_state = BIT(state), \
+			.id = _id, \
+		}, \
+		.genpd = { \
+			.name = _name, \
+			.power_on = pxa1908_pd_power_on, \
+			.power_off = pxa1908_pd_power_off, \
+		}, \
+	}
+
+static struct pxa1908_pd domains[NR_DOMAINS] = {
+	DOMAIN(PXA1908_POWER_DOMAIN_VPU, "vpu", 0xa4, 19, 2),
+	DOMAIN(PXA1908_POWER_DOMAIN_GPU, "gpu", 0xcc, 11, 0),
+	DOMAIN(PXA1908_POWER_DOMAIN_GPU2D, "gpu2d", 0xf4, 11, 6),
+	DOMAIN(PXA1908_POWER_DOMAIN_ISP, "isp", 0x38, 15, 4),
+	[PXA1908_POWER_DOMAIN_DSI] = {
+		.genpd = {
+			.name = "dsi",
+			.power_on = pxa1908_dsi_power_on,
+			.power_off = pxa1908_dsi_power_off,
+			/*
+			 * TODO: There is no DSI driver written yet and until then we probably
+			 * don't want to power off the DSI PHY ever.
+			 */
+			.flags = GENPD_FLAG_ALWAYS_ON,
+		},
+		.data = {
+			/* See above. */
+			.keep_on = true,
+		},
+	},
+	[PXA1908_POWER_DOMAIN_AUDIO] = {
+		.genpd = {
+			.name = "audio",
+			.power_on = pxa1908_audio_power_on,
+			.power_off = pxa1908_audio_power_off,
+		},
+	},
+};
+
+static void pxa1908_pd_remove(struct auxiliary_device *auxdev)
+{
+	struct pxa1908_pd *pd;
+	int ret;
+
+	for (int i = NR_DOMAINS - 1; i >= 0; i--) {
+		pd = &domains[i];
+
+		if (!pd->initialized)
+			continue;
+
+		if (pxa1908_pd_is_on(pd) && !pd->data.keep_on)
+			pxa1908_pd_power_off(&pd->genpd);
+
+		ret = pm_genpd_remove(&pd->genpd);
+		if (ret)
+			dev_err(&auxdev->dev, "failed to remove domain '%s': %d\n",
+				pd->genpd.name, ret);
+	}
+}
+
+static int
+pxa1908_pd_init(struct pxa1908_pd_ctrl *ctrl, int id, struct device *dev)
+{
+	struct pxa1908_pd *pd = &domains[id];
+	int ret;
+
+	ctrl->domains[id] = &pd->genpd;
+
+	pd->ctrl = ctrl;
+
+	/* Make sure the state of the hardware is synced with the domain table above. */
+	if (pd->data.keep_on) {
+		ret = pd->genpd.power_on(&pd->genpd);
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to power on domain '%s'\n",
+					     pd->genpd.name);
+	} else {
+		if (pxa1908_pd_is_on(pd)) {
+			dev_warn(dev,
+				 "domain '%s' is on despite being default off; powering off\n",
+				 pd->genpd.name);
+
+			ret = pd->genpd.power_off(&pd->genpd);
+			if (ret)
+				return dev_err_probe(dev, ret,
+						     "failed to power off domain '%s'\n",
+						     pd->genpd.name);
+		}
+	}
+
+	ret = pm_genpd_init(&pd->genpd, NULL, !pd->data.keep_on);
+	if (ret)
+		return dev_err_probe(dev, ret, "domain '%s' failed to initialize\n",
+				     pd->genpd.name);
+
+	pd->initialized = true;
+
+	return 0;
+}
+
+static int
+pxa1908_pd_probe(struct auxiliary_device *auxdev, const struct auxiliary_device_id *aux_id)
+{
+	struct pxa1908_pd_ctrl *ctrl;
+	struct device *dev = &auxdev->dev;
+	int ret;
+
+	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
+	if (!ctrl)
+		return -ENOMEM;
+
+	auxiliary_set_drvdata(auxdev, ctrl);
+
+	ctrl->base = syscon_node_to_regmap(dev->parent->of_node);
+	if (IS_ERR(ctrl->base))
+		return dev_err_probe(dev, PTR_ERR(ctrl->base), "no regmap available\n");
+
+	ctrl->dev = dev;
+	ctrl->onecell_data.domains = ctrl->domains;
+	ctrl->onecell_data.num_domains = NR_DOMAINS;
+
+	for (int i = 0; i < NR_DOMAINS; i++) {
+		ret = pxa1908_pd_init(ctrl, i, dev);
+		if (ret)
+			goto err;
+	}
+
+	return of_genpd_add_provider_onecell(dev->parent->of_node, &ctrl->onecell_data);
+
+err:
+	pxa1908_pd_remove(auxdev);
+	return ret;
+}
+
+static const struct auxiliary_device_id pxa1908_pd_id[] = {
+	{ .name = "clk_pxa1908_apmu.power" },
+	{ }
+};
+MODULE_DEVICE_TABLE(auxiliary, pxa1908_pd_id);
+
+static struct auxiliary_driver pxa1908_pd_driver = {
+	.probe = pxa1908_pd_probe,
+	.remove = pxa1908_pd_remove,
+	.id_table = pxa1908_pd_id,
+};
+module_auxiliary_driver(pxa1908_pd_driver);
+
+MODULE_AUTHOR("Duje Mihanović <duje@dujemihanovic.xyz>");
+MODULE_DESCRIPTION("Marvell PXA1908 power domain driver");
+MODULE_LICENSE("GPL");