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, 129 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/ulpi.c b/drivers/usb/dwc3/ulpi.c
new file mode 100644
index 000000000..a256b7f5d
--- /dev/null
+++ b/drivers/usb/dwc3/ulpi.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
+ *
+ * Copyright (C) 2015 Intel Corporation
+ *
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/time64.h>
+#include <linux/ulpi/regs.h>
+#include <linux/ulpi/driver.h>
+
+#include "core.h"
+#include "io.h"
+
+#define USB_VENDOR_MICROCHIP 0x0424
+
+#define DWC3_ULPI_ADDR(a) \
+		((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
+		DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
+		DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))
+
+#define DWC3_ULPI_BASE_DELAY	DIV_ROUND_UP(NSEC_PER_SEC, 60000000L)
+
+static int dwc3_ulpi_busyloop(struct dwc3 *dwc, u8 addr, bool read)
+{
+	unsigned long ns = 5L * DWC3_ULPI_BASE_DELAY;
+	unsigned int count = 10000;
+	u32 reg;
+
+	if (addr >= ULPI_EXT_VENDOR_SPECIFIC)
+		ns += DWC3_ULPI_BASE_DELAY;
+
+	if (read)
+		ns += DWC3_ULPI_BASE_DELAY;
+
+	reg = dwc3_readl(dwc, DWC3_GUSB2PHYCFG(0));
+	if (reg & DWC3_GUSB2PHYCFG_SUSPHY)
+		usleep_range(1000, 1200);
+
+	while (count--) {
+		ndelay(ns);
+		reg = dwc3_readl(dwc, DWC3_GUSB2PHYACC(0));
+		if (reg & DWC3_GUSB2PHYACC_DONE)
+			return 0;
+		cpu_relax();
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int dwc3_ulpi_read(struct device *dev, u8 addr)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	u32 reg;
+	int ret;
+
+	reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
+	dwc3_writel(dwc, DWC3_GUSB2PHYACC(0), reg);
+
+	ret = dwc3_ulpi_busyloop(dwc, addr, true);
+	if (ret)
+		return ret;
+
+	reg = dwc3_readl(dwc, DWC3_GUSB2PHYACC(0));
+
+	return DWC3_GUSB2PHYACC_DATA(reg);
+}
+
+static int dwc3_ulpi_write(struct device *dev, u8 addr, u8 val)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	u32 reg;
+
+	reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
+	reg |= DWC3_GUSB2PHYACC_WRITE | val;
+	dwc3_writel(dwc, DWC3_GUSB2PHYACC(0), reg);
+
+	return dwc3_ulpi_busyloop(dwc, addr, false);
+}
+
+static const struct ulpi_ops dwc3_ulpi_ops = {
+	.read = dwc3_ulpi_read,
+	.write = dwc3_ulpi_write,
+};
+
+static void dwc3_ulpi_detect_config(struct dwc3 *dwc)
+{
+	struct ulpi *ulpi = dwc->ulpi;
+
+	switch (ulpi->id.vendor) {
+	case USB_VENDOR_MICROCHIP:
+		switch (ulpi->id.product) {
+		case 0x0009:
+			/* Microchip USB3340 ULPI PHY */
+			dwc->enable_usb2_transceiver_delay = true;
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+int dwc3_ulpi_init(struct dwc3 *dwc)
+{
+	/* Register the interface */
+	dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
+	if (IS_ERR(dwc->ulpi)) {
+		dev_err(dwc->dev, "failed to register ULPI interface");
+		return PTR_ERR(dwc->ulpi);
+	}
+
+	dwc3_ulpi_detect_config(dwc);
+
+	return 0;
+}
+
+void dwc3_ulpi_exit(struct dwc3 *dwc)
+{
+	if (dwc->ulpi) {
+		ulpi_unregister_interface(dwc->ulpi);
+		dwc->ulpi = NULL;
+	}
+}