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, 182 insertions, 0 deletions

diff --git a/drivers/phy/phy-econet-pcie.c b/drivers/phy/phy-econet-pcie.c
new file mode 100644
index 000000000..96be69d1f
--- /dev/null
+++ b/drivers/phy/phy-econet-pcie.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Author: Caleb James DeLisle <cjd@cjdns.fr>
+ *	   Ahmed Naseef <naseefkm@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+
+/* Rx detection timing for EN751221: 16*8 clock cycles  */
+#define EN751221_RXDET_VAL		16
+
+/* Rx detection timing when in power mode 3 */
+#define EN75_RXDET_P3_REG		0xa28
+#define EN75_RXDET_P3_MASK		GENMASK(17, 9)
+
+/* Rx detection timing when in power mode 2 */
+#define EN75_RXDET_P2_REG		0xa2c
+#define EN75_RXDET_P2_MASK		GENMASK(8, 0)
+
+/* Rx impedance */
+#define EN75_RX_IMPEDANCE_REG		0xb2c
+#define EN75_RX_IMPEDANCE_MASK		GENMASK(13, 12)
+enum en75_rx_impedance {
+	EN75_RX_IMPEDANCE_100_OHM	= 0,
+	EN75_RX_IMPEDANCE_95_OHM	= 1,
+	EN75_RX_IMPEDANCE_90_OHM	= 2,
+};
+
+/* PLL Invert clock */
+#define EN75_PLL_PH_INV_REG		0x4a0
+#define EN75_PLL_PH_INV_MASK		BIT(5)
+
+struct en75_phy_op {
+	u32 reg;
+	u32 mask;
+	u32 val;
+};
+
+struct en7528_pcie_phy {
+	struct regmap *regmap;
+	const struct en75_phy_op *data;
+};
+
+/* Port 0 PHY: set LCDDS_CLK_PH_INV for PLL operation */
+static const struct en75_phy_op en7528_phy_gen1[] = {
+	{
+		.reg = EN75_PLL_PH_INV_REG,
+		.mask = EN75_PLL_PH_INV_MASK,
+		.val = 1,
+	},
+	{ /* sentinel */ }
+};
+
+/* EN7528 Port 1 PHY: Rx impedance tuning, target R -5 Ohm */
+static const struct en75_phy_op en7528_phy_gen2[] = {
+	{
+		.reg = EN75_RX_IMPEDANCE_REG,
+		.mask = EN75_RX_IMPEDANCE_MASK,
+		.val = EN75_RX_IMPEDANCE_95_OHM,
+	},
+	{ /* sentinel */ }
+};
+
+/* EN751221 Port 1 PHY, set RX detect to 16*8 clock cycles */
+static const struct en75_phy_op en751221_phy_gen2[] = {
+	{
+		.reg = EN75_RXDET_P3_REG,
+		.mask = EN75_RXDET_P3_MASK,
+		.val = EN751221_RXDET_VAL,
+	},
+	{
+		.reg = EN75_RXDET_P2_REG,
+		.mask = EN75_RXDET_P2_MASK,
+		.val = EN751221_RXDET_VAL,
+	},
+	{ /* sentinel */ }
+};
+
+static int en75_pcie_phy_init(struct phy *phy)
+{
+	struct en7528_pcie_phy *ephy = phy_get_drvdata(phy);
+	const struct en75_phy_op *data = ephy->data;
+	int i, ret;
+	u32 val;
+
+	for (i = 0; data[i].mask || data[i].val; i++) {
+		if (i)
+			usleep_range(1000, 2000);
+
+		val = field_prep(data[i].mask, data[i].val);
+
+		ret = regmap_update_bits(ephy->regmap, data[i].reg,
+					 data[i].mask, val);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct phy_ops en75_pcie_phy_ops = {
+	.init	= en75_pcie_phy_init,
+	.owner	= THIS_MODULE,
+};
+
+static int en75_pcie_phy_probe(struct platform_device *pdev)
+{
+	struct regmap_config regmap_config = {
+		.reg_bits = 32,
+		.val_bits = 32,
+		.reg_stride = 4,
+	};
+	struct device *dev = &pdev->dev;
+	const struct en75_phy_op *data;
+	struct phy_provider *provider;
+	struct en7528_pcie_phy *ephy;
+	void __iomem *base;
+	struct phy *phy;
+	int i;
+
+	data = of_device_get_match_data(dev);
+	if (!data)
+		return -EINVAL;
+
+	ephy = devm_kzalloc(dev, sizeof(*ephy), GFP_KERNEL);
+	if (!ephy)
+		return -ENOMEM;
+
+	ephy->data = data;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	/* Set max_register to highest used register */
+	for (i = 0; data[i].mask || data[i].val; i++)
+		if (data[i].reg > regmap_config.max_register)
+			regmap_config.max_register = data[i].reg;
+
+	ephy->regmap = devm_regmap_init_mmio(dev, base, &regmap_config);
+	if (IS_ERR(ephy->regmap))
+		return PTR_ERR(ephy->regmap);
+
+	phy = devm_phy_create(dev, dev->of_node, &en75_pcie_phy_ops);
+	if (IS_ERR(phy))
+		return PTR_ERR(phy);
+
+	phy_set_drvdata(phy, ephy);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(provider);
+}
+
+static const struct of_device_id en75_pcie_phy_ids[] = {
+	{ .compatible = "econet,en7528-pcie-gen1", .data = en7528_phy_gen1 },
+	{ .compatible = "econet,en7528-pcie-gen2", .data = en7528_phy_gen2 },
+	{ .compatible = "econet,en751221-pcie-gen1", .data = en7528_phy_gen1 },
+	{ .compatible = "econet,en751221-pcie-gen2", .data = en751221_phy_gen2 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, en75_pcie_phy_ids);
+
+static struct platform_driver en75_pcie_phy_driver = {
+	.probe = en75_pcie_phy_probe,
+	.driver = {
+		.name = "econet-pcie-phy",
+		.of_match_table = en75_pcie_phy_ids,
+	},
+};
+module_platform_driver(en75_pcie_phy_driver);
+
+MODULE_AUTHOR("Caleb James DeLisle <cjd@cjdns.fr>");
+MODULE_DESCRIPTION("EcoNet PCIe PHY driver");
+MODULE_LICENSE("GPL");