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, 168 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/host.c b/drivers/usb/cdns3/host.c
new file mode 100644
index 000000000..f0df114c2
--- /dev/null
+++ b/drivers/usb/cdns3/host.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS and USBSSP DRD Driver - host side
+ *
+ * Copyright (C) 2018-2019 Cadence Design Systems.
+ * Copyright (C) 2017-2018 NXP
+ *
+ * Authors: Peter Chen <peter.chen@nxp.com>
+ *          Pawel Laszczak <pawell@cadence.com>
+ */
+
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include "core.h"
+#include "drd.h"
+#include "host-export.h"
+#include <linux/usb/hcd.h>
+#include "../host/xhci.h"
+#include "../host/xhci-plat.h"
+
+/*
+ * The XECP_PORT_CAP_REG and XECP_AUX_CTRL_REG1 exist only
+ * in Cadence USB3 dual-role controller, so it can't be used
+ * with Cadence CDNSP dual-role controller.
+ */
+#define XECP_PORT_CAP_REG	0x8000
+#define XECP_AUX_CTRL_REG1	0x8120
+
+#define CFG_RXDET_P3_EN		BIT(15)
+#define LPM_2_STB_SWITCH_EN	BIT(25)
+
+static void xhci_cdns3_plat_start(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	u32 value;
+
+	/* set usbcmd.EU3S */
+	value = readl(&xhci->op_regs->command);
+	value |= CMD_PM_INDEX;
+	writel(value, &xhci->op_regs->command);
+
+	if (hcd->regs) {
+		value = readl(hcd->regs + XECP_AUX_CTRL_REG1);
+		value |= CFG_RXDET_P3_EN;
+		writel(value, hcd->regs + XECP_AUX_CTRL_REG1);
+
+		value = readl(hcd->regs + XECP_PORT_CAP_REG);
+		value |= LPM_2_STB_SWITCH_EN;
+		writel(value, hcd->regs + XECP_PORT_CAP_REG);
+	}
+}
+
+static int xhci_cdns3_resume_quirk(struct usb_hcd *hcd)
+{
+	xhci_cdns3_plat_start(hcd);
+	return 0;
+}
+
+static const struct xhci_plat_priv xhci_plat_cdns3_xhci = {
+	.quirks = XHCI_SKIP_PHY_INIT | XHCI_AVOID_BEI,
+	.plat_start = xhci_cdns3_plat_start,
+	.resume_quirk = xhci_cdns3_resume_quirk,
+};
+
+static const struct xhci_plat_priv xhci_plat_cdnsp_xhci = {
+	.quirks = XHCI_CDNS_SCTX_QUIRK,
+};
+
+static int __cdns_host_init(struct cdns *cdns)
+{
+	struct platform_device *xhci;
+	int ret;
+	struct usb_hcd *hcd;
+
+	cdns_drd_host_on(cdns);
+
+	xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO);
+	if (!xhci) {
+		dev_err(cdns->dev, "couldn't allocate xHCI device\n");
+		return -ENOMEM;
+	}
+
+	xhci->dev.parent = cdns->dev;
+	cdns->host_dev = xhci;
+
+	ret = platform_device_add_resources(xhci, cdns->xhci_res,
+					    CDNS_XHCI_RESOURCES_NUM);
+	if (ret) {
+		dev_err(cdns->dev, "couldn't add resources to xHCI device\n");
+		goto err1;
+	}
+
+	if (cdns->version < CDNSP_CONTROLLER_V2)
+		cdns->xhci_plat_data = kmemdup(&xhci_plat_cdns3_xhci,
+				sizeof(struct xhci_plat_priv), GFP_KERNEL);
+	else
+		cdns->xhci_plat_data = kmemdup(&xhci_plat_cdnsp_xhci,
+				sizeof(struct xhci_plat_priv), GFP_KERNEL);
+
+	if (!cdns->xhci_plat_data) {
+		ret = -ENOMEM;
+		goto err1;
+	}
+
+	if (cdns->pdata && (cdns->pdata->quirks & CDNS3_DEFAULT_PM_RUNTIME_ALLOW))
+		cdns->xhci_plat_data->quirks |= XHCI_DEFAULT_PM_RUNTIME_ALLOW;
+
+	ret = platform_device_add_data(xhci, cdns->xhci_plat_data,
+			sizeof(struct xhci_plat_priv));
+	if (ret)
+		goto free_memory;
+
+	ret = platform_device_add(xhci);
+	if (ret) {
+		dev_err(cdns->dev, "failed to register xHCI device\n");
+		goto free_memory;
+	}
+
+	/* Glue needs to access xHCI region register for Power management */
+	hcd = platform_get_drvdata(xhci);
+	if (hcd)
+		cdns->xhci_regs = hcd->regs;
+
+	return 0;
+
+free_memory:
+	kfree(cdns->xhci_plat_data);
+err1:
+	platform_device_put(xhci);
+	return ret;
+}
+
+static void cdns_host_exit(struct cdns *cdns)
+{
+	kfree(cdns->xhci_plat_data);
+	platform_device_unregister(cdns->host_dev);
+	cdns->host_dev = NULL;
+	cdns_drd_host_off(cdns);
+}
+
+static int cdns_host_resume(struct cdns *cdns, bool power_lost)
+{
+	struct usb_hcd *hcd = platform_get_drvdata(cdns->host_dev);
+	struct xhci_plat_priv *priv = hcd_to_xhci_priv(hcd);
+
+	priv->power_lost = power_lost;
+
+	return 0;
+}
+
+int cdns_host_init(struct cdns *cdns)
+{
+	struct cdns_role_driver *rdrv;
+
+	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
+	if (!rdrv)
+		return -ENOMEM;
+
+	rdrv->start	= __cdns_host_init;
+	rdrv->stop	= cdns_host_exit;
+	rdrv->resume	= cdns_host_resume;
+	rdrv->state	= CDNS_ROLE_STATE_INACTIVE;
+	rdrv->name	= "host";
+
+	cdns->roles[USB_ROLE_HOST] = rdrv;
+
+	return 0;
+}