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, 245 insertions, 0 deletions

diff --git a/drivers/phy/broadcom/phy-bcm-ns-usb3.c b/drivers/phy/broadcom/phy-bcm-ns-usb3.c
new file mode 100644
index 000000000..9240600ae
--- /dev/null
+++ b/drivers/phy/broadcom/phy-bcm-ns-usb3.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Broadcom Northstar USB 3.0 PHY Driver
+ *
+ * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
+ * Copyright (C) 2016 Broadcom
+ *
+ * All magic values used for initialization (and related comments) were obtained
+ * from Broadcom's SDK:
+ * Copyright (c) Broadcom Corp, 2012
+ */
+
+#include <linux/bcma/bcma.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/mdio.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/phy/phy.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+#define BCM_NS_USB3_PHY_BASE_ADDR_REG	0x1f
+#define BCM_NS_USB3_PHY_PLL30_BLOCK	0x8000
+#define BCM_NS_USB3_PHY_TX_PMD_BLOCK	0x8040
+#define BCM_NS_USB3_PHY_PIPE_BLOCK	0x8060
+
+/* Registers of PLL30 block */
+#define BCM_NS_USB3_PLL_CONTROL		0x01
+#define BCM_NS_USB3_PLLA_CONTROL0	0x0a
+#define BCM_NS_USB3_PLLA_CONTROL1	0x0b
+
+/* Registers of TX PMD block */
+#define BCM_NS_USB3_TX_PMD_CONTROL1	0x01
+
+/* Registers of PIPE block */
+#define BCM_NS_USB3_LFPS_CMP		0x02
+#define BCM_NS_USB3_LFPS_DEGLITCH	0x03
+
+enum bcm_ns_family {
+	BCM_NS_UNKNOWN,
+	BCM_NS_AX,
+	BCM_NS_BX,
+};
+
+struct bcm_ns_usb3 {
+	struct device *dev;
+	enum bcm_ns_family family;
+	void __iomem *dmp;
+	struct mdio_device *mdiodev;
+	struct phy *phy;
+};
+
+static const struct of_device_id bcm_ns_usb3_id_table[] = {
+	{
+		.compatible = "brcm,ns-ax-usb3-phy",
+		.data = (int *)BCM_NS_AX,
+	},
+	{
+		.compatible = "brcm,ns-bx-usb3-phy",
+		.data = (int *)BCM_NS_BX,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm_ns_usb3_id_table);
+
+static int bcm_ns_usb3_mdio_phy_write(struct bcm_ns_usb3 *usb3, u16 reg,
+				      u16 value);
+
+static int bcm_ns_usb3_phy_init_ns_bx(struct bcm_ns_usb3 *usb3)
+{
+	int err;
+
+	/* USB3 PLL Block */
+	err = bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PHY_BASE_ADDR_REG,
+					 BCM_NS_USB3_PHY_PLL30_BLOCK);
+	if (err < 0)
+		return err;
+
+	/* Assert Ana_Pllseq start */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PLL_CONTROL, 0x1000);
+
+	/* Assert CML Divider ratio to 26 */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PLLA_CONTROL0, 0x6400);
+
+	/* Asserting PLL Reset */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PLLA_CONTROL1, 0xc000);
+
+	/* Deaaserting PLL Reset */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PLLA_CONTROL1, 0x8000);
+
+	/* Deasserting USB3 system reset */
+	writel(0, usb3->dmp + BCMA_RESET_CTL);
+
+	/* PLL frequency monitor enable */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PLL_CONTROL, 0x9000);
+
+	/* PIPE Block */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PHY_BASE_ADDR_REG,
+				   BCM_NS_USB3_PHY_PIPE_BLOCK);
+
+	/* CMPMAX & CMPMINTH setting */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_LFPS_CMP, 0xf30d);
+
+	/* DEGLITCH MIN & MAX setting */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_LFPS_DEGLITCH, 0x6302);
+
+	/* TXPMD block */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PHY_BASE_ADDR_REG,
+				   BCM_NS_USB3_PHY_TX_PMD_BLOCK);
+
+	/* Enabling SSC */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_TX_PMD_CONTROL1, 0x1003);
+
+	return 0;
+}
+
+static int bcm_ns_usb3_phy_init_ns_ax(struct bcm_ns_usb3 *usb3)
+{
+	int err;
+
+	/* PLL30 block */
+	err = bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PHY_BASE_ADDR_REG,
+					 BCM_NS_USB3_PHY_PLL30_BLOCK);
+	if (err < 0)
+		return err;
+
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PLLA_CONTROL0, 0x6400);
+
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PHY_BASE_ADDR_REG, 0x80e0);
+
+	bcm_ns_usb3_mdio_phy_write(usb3, 0x02, 0x009c);
+
+	/* Enable SSC */
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_PHY_BASE_ADDR_REG,
+				   BCM_NS_USB3_PHY_TX_PMD_BLOCK);
+
+	bcm_ns_usb3_mdio_phy_write(usb3, 0x02, 0x21d3);
+
+	bcm_ns_usb3_mdio_phy_write(usb3, BCM_NS_USB3_TX_PMD_CONTROL1, 0x1003);
+
+	/* Deasserting USB3 system reset */
+	writel(0, usb3->dmp + BCMA_RESET_CTL);
+
+	return 0;
+}
+
+static int bcm_ns_usb3_phy_init(struct phy *phy)
+{
+	struct bcm_ns_usb3 *usb3 = phy_get_drvdata(phy);
+	int err;
+
+	/* Perform USB3 system soft reset */
+	writel(BCMA_RESET_CTL_RESET, usb3->dmp + BCMA_RESET_CTL);
+
+	switch (usb3->family) {
+	case BCM_NS_AX:
+		err = bcm_ns_usb3_phy_init_ns_ax(usb3);
+		break;
+	case BCM_NS_BX:
+		err = bcm_ns_usb3_phy_init_ns_bx(usb3);
+		break;
+	default:
+		WARN_ON(1);
+		err = -ENOTSUPP;
+	}
+
+	return err;
+}
+
+static const struct phy_ops ops = {
+	.init		= bcm_ns_usb3_phy_init,
+	.owner		= THIS_MODULE,
+};
+
+/**************************************************
+ * MDIO driver code
+ **************************************************/
+
+static int bcm_ns_usb3_mdio_phy_write(struct bcm_ns_usb3 *usb3, u16 reg,
+				      u16 value)
+{
+	struct mdio_device *mdiodev = usb3->mdiodev;
+
+	return mdiodev_write(mdiodev, reg, value);
+}
+
+static int bcm_ns_usb3_mdio_probe(struct mdio_device *mdiodev)
+{
+	struct device *dev = &mdiodev->dev;
+	struct phy_provider *phy_provider;
+	struct device_node *syscon_np;
+	struct bcm_ns_usb3 *usb3;
+	struct resource res;
+	int err;
+
+	usb3 = devm_kzalloc(dev, sizeof(*usb3), GFP_KERNEL);
+	if (!usb3)
+		return -ENOMEM;
+
+	usb3->dev = dev;
+	usb3->mdiodev = mdiodev;
+
+	usb3->family = (unsigned long)device_get_match_data(dev);
+
+	syscon_np = of_parse_phandle(dev->of_node, "usb3-dmp-syscon", 0);
+	err = of_address_to_resource(syscon_np, 0, &res);
+	of_node_put(syscon_np);
+	if (err)
+		return err;
+
+	usb3->dmp = devm_ioremap_resource(dev, &res);
+	if (IS_ERR(usb3->dmp))
+		return PTR_ERR(usb3->dmp);
+
+	usb3->phy = devm_phy_create(dev, NULL, &ops);
+	if (IS_ERR(usb3->phy)) {
+		dev_err(dev, "Failed to create PHY\n");
+		return PTR_ERR(usb3->phy);
+	}
+
+	phy_set_drvdata(usb3->phy, usb3);
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct mdio_driver bcm_ns_usb3_mdio_driver = {
+	.mdiodrv = {
+		.driver = {
+			.name = "bcm_ns_mdio_usb3",
+			.of_match_table = bcm_ns_usb3_id_table,
+		},
+	},
+	.probe = bcm_ns_usb3_mdio_probe,
+};
+
+mdio_module_driver(bcm_ns_usb3_mdio_driver);
+
+MODULE_DESCRIPTION("Broadcom Northstar USB 3.0 PHY Driver");
+MODULE_LICENSE("GPL v2");