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, 229 insertions, 0 deletions

diff --git a/drivers/phy/axiado/Kconfig b/drivers/phy/axiado/Kconfig
new file mode 100644
index 000000000..d159e0345
--- /dev/null
+++ b/drivers/phy/axiado/Kconfig
@@ -0,0 +1,11 @@
+#
+# PHY drivers for Axiado platforms
+#
+
+config PHY_AX3000_EMMC
+	tristate "Axiado eMMC PHY driver"
+	depends on OF && (ARCH_AXIADO || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enables this to support for the AX3000 EMMC PHY driver.
+	  If unsure, say N.
diff --git a/drivers/phy/axiado/Makefile b/drivers/phy/axiado/Makefile
new file mode 100644
index 000000000..1e2b1ba01
--- /dev/null
+++ b/drivers/phy/axiado/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_PHY_AX3000_EMMC)		+= phy-axiado-emmc.o
diff --git a/drivers/phy/axiado/phy-axiado-emmc.c b/drivers/phy/axiado/phy-axiado-emmc.c
new file mode 100644
index 000000000..e0e217477
--- /dev/null
+++ b/drivers/phy/axiado/phy-axiado-emmc.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Axiado eMMC PHY driver
+ *
+ * Copyright (C) 2017 Arasan Chip Systems Inc.
+ * Copyright (C) 2022-2026 Axiado Corporation (or its affiliates).
+ *
+ * Based on Arasan Driver (sdhci-pci-arasan.c)
+ * sdhci-pci-arasan.c - Driver for Arasan PCI Controller with integrated phy.
+ */
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+
+/* Arasan eMMC 5.1 - PHY configuration registers */
+#define CAP_REG_IN_S1_MSB		0x04
+#define PHY_CTRL_1			0x38
+#define PHY_CTRL_2			0x3c
+#define PHY_CTRL_3			0x40
+#define STATUS				0x50
+
+#define DLL_ENBL	BIT(26)
+#define RTRIM_EN	BIT(21)
+#define PDB_ENBL	BIT(23)
+#define RETB_ENBL	BIT(1)
+
+#define REN_STRB	BIT(27)
+#define REN_CMD_EN	GENMASK(20, 12)
+
+/* Pull-UP Enable on CMD Line */
+#define PU_CMD_EN	GENMASK(11, 3)
+
+/* Selection value for the optimum delay from 1-32 output tap lines */
+#define OTAP_DLY	0x02
+/* DLL charge pump current trim default [1000] */
+#define DLL_TRM_ICP	0x08
+/* Select the frequency range of DLL Operation */
+#define FRQ_SEL	0x01
+
+#define OTAP_SEL_MASK		GENMASK(10, 7)
+#define DLL_TRM_MASK		GENMASK(25, 22)
+#define DLL_FRQSEL_MASK		GENMASK(27, 25)
+
+#define OTAP_SEL(x)		(FIELD_PREP(OTAP_SEL_MASK, x) | OTAPDLY_EN)
+#define DLL_TRM(x)		(FIELD_PREP(DLL_TRM_MASK, x) | DLL_ENBL)
+#define DLL_FRQSEL(x)	FIELD_PREP(DLL_FRQSEL_MASK, x)
+
+#define OTAPDLY_EN	BIT(11)
+
+#define SEL_DLY_RXCLK	BIT(18)
+#define SEL_DLY_TXCLK	BIT(19)
+
+#define CALDONE_MASK	0x40
+#define DLL_RDY_MASK	0x1
+#define MAX_CLK_BUF0	BIT(20)
+#define MAX_CLK_BUF1	BIT(21)
+#define MAX_CLK_BUF2	BIT(22)
+
+#define CLK_MULTIPLIER	0xc008e
+#define POLL_TIMEOUT_MS	3000
+#define POLL_DELAY_US	100
+
+struct axiado_emmc_phy {
+	void __iomem *reg_base;
+	struct device *dev;
+};
+
+static int axiado_emmc_phy_init(struct phy *phy)
+{
+	struct axiado_emmc_phy *ax_phy = phy_get_drvdata(phy);
+	struct device *dev = ax_phy->dev;
+	u32 val;
+	int ret;
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_1);
+	writel(val | RETB_ENBL | RTRIM_EN, ax_phy->reg_base + PHY_CTRL_1);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_3);
+	writel(val | PDB_ENBL, ax_phy->reg_base + PHY_CTRL_3);
+
+	ret = readl_poll_timeout(ax_phy->reg_base + STATUS, val,
+				 val & CALDONE_MASK, POLL_DELAY_US,
+				 POLL_TIMEOUT_MS * 1000);
+	if (ret) {
+		dev_err(dev, "PHY calibration timeout\n");
+		return ret;
+	}
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_1);
+	writel(val | REN_CMD_EN | PU_CMD_EN, ax_phy->reg_base + PHY_CTRL_1);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_2);
+	writel(val | REN_STRB, ax_phy->reg_base + PHY_CTRL_2);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_3);
+	writel(val | MAX_CLK_BUF0 | MAX_CLK_BUF1 | MAX_CLK_BUF2,
+	       ax_phy->reg_base + PHY_CTRL_3);
+
+	writel(CLK_MULTIPLIER, ax_phy->reg_base + CAP_REG_IN_S1_MSB);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_3);
+	writel(val | SEL_DLY_RXCLK | SEL_DLY_TXCLK,
+	       ax_phy->reg_base + PHY_CTRL_3);
+
+	return 0;
+}
+
+static int axiado_emmc_phy_power_on(struct phy *phy)
+{
+	struct axiado_emmc_phy *ax_phy = phy_get_drvdata(phy);
+	struct device *dev = ax_phy->dev;
+	u32 val;
+	int ret;
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_1);
+	writel(val | RETB_ENBL, ax_phy->reg_base + PHY_CTRL_1);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_3);
+	writel(val | PDB_ENBL, ax_phy->reg_base + PHY_CTRL_3);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_2);
+	writel(val | OTAP_SEL(OTAP_DLY), ax_phy->reg_base + PHY_CTRL_2);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_1);
+	writel(val | DLL_TRM(DLL_TRM_ICP), ax_phy->reg_base + PHY_CTRL_1);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_3);
+	writel(val | DLL_FRQSEL(FRQ_SEL), ax_phy->reg_base + PHY_CTRL_3);
+
+	ret = read_poll_timeout(readl, val, val & DLL_RDY_MASK, POLL_DELAY_US,
+				POLL_TIMEOUT_MS * 1000, false,
+				ax_phy->reg_base + STATUS);
+	if (ret) {
+		dev_err(dev, "DLL ready timeout\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int axiado_emmc_phy_power_off(struct phy *phy)
+{
+	struct axiado_emmc_phy *ax_phy = phy_get_drvdata(phy);
+	u32 val;
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_1);
+	val &= ~(DLL_TRM_MASK | DLL_ENBL);
+	writel(val, ax_phy->reg_base + PHY_CTRL_1);
+
+	val = readl(ax_phy->reg_base + PHY_CTRL_3);
+	val &= ~(DLL_FRQSEL_MASK | PDB_ENBL);
+	writel(val, ax_phy->reg_base + PHY_CTRL_3);
+
+	return 0;
+}
+
+static const struct phy_ops axiado_emmc_phy_ops = {
+	.init = axiado_emmc_phy_init,
+	.power_on = axiado_emmc_phy_power_on,
+	.power_off = axiado_emmc_phy_power_off,
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id axiado_emmc_phy_of_match[] = {
+	{ .compatible = "axiado,ax3000-emmc-phy" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, axiado_emmc_phy_of_match);
+
+static int axiado_emmc_phy_probe(struct platform_device *pdev)
+{
+	struct axiado_emmc_phy *ax_phy;
+	struct phy_provider *phy_provider;
+	struct device *dev = &pdev->dev;
+	struct phy *generic_phy;
+
+	if (!dev->of_node)
+		return -ENODEV;
+
+	ax_phy = devm_kzalloc(dev, sizeof(*ax_phy), GFP_KERNEL);
+	if (!ax_phy)
+		return -ENOMEM;
+
+	ax_phy->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ax_phy->reg_base))
+		return PTR_ERR(ax_phy->reg_base);
+
+	ax_phy->dev = dev;
+
+	generic_phy = devm_phy_create(dev, dev->of_node, &axiado_emmc_phy_ops);
+	if (IS_ERR(generic_phy))
+		return dev_err_probe(dev, PTR_ERR(generic_phy),
+				     "failed to create PHY\n");
+
+	phy_set_drvdata(generic_phy, ax_phy);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct platform_driver axiado_emmc_phy_driver = {
+	.probe = axiado_emmc_phy_probe,
+	.driver = {
+		.name = "axiado-emmc-phy",
+		.of_match_table = axiado_emmc_phy_of_match,
+	},
+};
+module_platform_driver(axiado_emmc_phy_driver);
+
+MODULE_DESCRIPTION("AX3000 eMMC PHY Driver");
+MODULE_AUTHOR("Axiado Corporation");
+MODULE_LICENSE("GPL");