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, 299 insertions, 0 deletions

diff --git a/drivers/ata/pata_it8213.c b/drivers/ata/pata_it8213.c
new file mode 100644
index 000000000..a6f2cfc16
--- /dev/null
+++ b/drivers/ata/pata_it8213.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *    pata_it8213.c - iTE Tech. Inc.  IT8213 PATA driver
+ *
+ *    The IT8213 is a very Intel ICH like device for timing purposes, having
+ *    a similar register layout and the same split clock arrangement. Cable
+ *    detection is different, and it does not have slave channels or all the
+ *    clutter of later ICH/SATA setups.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <scsi/scsi_host.h>
+#include <linux/libata.h>
+#include <linux/ata.h>
+
+#define DRV_NAME	"pata_it8213"
+#define DRV_VERSION	"0.0.3"
+
+/**
+ *	it8213_pre_reset	-	probe begin
+ *	@link: link
+ *	@deadline: deadline jiffies for the operation
+ *
+ *	Filter out ports by the enable bits before doing the normal reset
+ *	and probe.
+ */
+
+static int it8213_pre_reset(struct ata_link *link, unsigned long deadline)
+{
+	static const struct pci_bits it8213_enable_bits[] = {
+		{ 0x41U, 1U, 0x80UL, 0x80UL },	/* port 0 */
+	};
+	struct ata_port *ap = link->ap;
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	if (!pci_test_config_bits(pdev, &it8213_enable_bits[ap->port_no]))
+		return -ENOENT;
+
+	return ata_sff_prereset(link, deadline);
+}
+
+/**
+ *	it8213_cable_detect	-	check for 40/80 pin
+ *	@ap: Port
+ *
+ *	Perform cable detection for the 8213 ATA interface. This is
+ *	different to the PIIX arrangement
+ */
+
+static int it8213_cable_detect(struct ata_port *ap)
+{
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u8 tmp;
+	pci_read_config_byte(pdev, 0x42, &tmp);
+	if (tmp & 2)	/* The initial docs are incorrect */
+		return ATA_CBL_PATA40;
+	return ATA_CBL_PATA80;
+}
+
+/**
+ *	it8213_set_piomode - Initialize host controller PATA PIO timings
+ *	@ap: Port whose timings we are configuring
+ *	@adev: Device whose timings we are configuring
+ *
+ *	Set PIO mode for device, in host controller PCI config space.
+ *
+ *	LOCKING:
+ *	None (inherited from caller).
+ */
+
+static void it8213_set_piomode (struct ata_port *ap, struct ata_device *adev)
+{
+	unsigned int pio	= adev->pio_mode - XFER_PIO_0;
+	struct pci_dev *dev	= to_pci_dev(ap->host->dev);
+	unsigned int master_port = ap->port_no ? 0x42 : 0x40;
+	u16 master_data;
+	int control = 0;
+
+	/*
+	 *	See Intel Document 298600-004 for the timing programming rules
+	 *	for PIIX/ICH. The 8213 is a clone so very similar
+	 */
+
+	static const	 /* ISP  RTC */
+	u8 timings[][2]	= { { 0, 0 },
+			    { 0, 0 },
+			    { 1, 0 },
+			    { 2, 1 },
+			    { 2, 3 }, };
+
+	if (pio > 1)
+		control |= 1;	/* TIME */
+	if (ata_pio_need_iordy(adev))	/* PIO 3/4 require IORDY */
+		control |= 2;	/* IE */
+	/* Bit 2 is set for ATAPI on the IT8213 - reverse of ICH/PIIX */
+	if (adev->class != ATA_DEV_ATA)
+		control |= 4;	/* PPE */
+
+	pci_read_config_word(dev, master_port, &master_data);
+
+	/* Set PPE, IE, and TIME as appropriate */
+	if (adev->devno == 0) {
+		master_data &= 0xCCF0;
+		master_data |= control;
+		master_data |= (timings[pio][0] << 12) |
+			(timings[pio][1] << 8);
+	} else {
+		u8 slave_data;
+
+		master_data &= 0xFF0F;
+		master_data |= (control << 4);
+
+		/* Slave timing in separate register */
+		pci_read_config_byte(dev, 0x44, &slave_data);
+		slave_data &= 0xF0;
+		slave_data |= (timings[pio][0] << 2) | timings[pio][1];
+		pci_write_config_byte(dev, 0x44, slave_data);
+	}
+
+	master_data |= 0x4000;	/* Ensure SITRE is set */
+	pci_write_config_word(dev, master_port, master_data);
+}
+
+/**
+ *	it8213_set_dmamode - Initialize host controller PATA DMA timings
+ *	@ap: Port whose timings we are configuring
+ *	@adev: Device to program
+ *
+ *	Set UDMA/MWDMA mode for device, in host controller PCI config space.
+ *	This device is basically an ICH alike.
+ *
+ *	LOCKING:
+ *	None (inherited from caller).
+ */
+
+static void it8213_set_dmamode (struct ata_port *ap, struct ata_device *adev)
+{
+	struct pci_dev *dev	= to_pci_dev(ap->host->dev);
+	u16 master_data;
+	u8 speed		= adev->dma_mode;
+	int devid		= adev->devno;
+	u8 udma_enable;
+
+	static const	 /* ISP  RTC */
+	u8 timings[][2]	= { { 0, 0 },
+			    { 0, 0 },
+			    { 1, 0 },
+			    { 2, 1 },
+			    { 2, 3 }, };
+
+	pci_read_config_word(dev, 0x40, &master_data);
+	pci_read_config_byte(dev, 0x48, &udma_enable);
+
+	if (speed >= XFER_UDMA_0) {
+		unsigned int udma = adev->dma_mode - XFER_UDMA_0;
+		u16 udma_timing;
+		u16 ideconf;
+		int u_clock, u_speed;
+
+		/* Clocks follow the PIIX style */
+		u_speed = min(2 - (udma & 1), udma);
+		if (udma > 4)
+			u_clock = 0x1000;	/* 100Mhz */
+		else if (udma > 2)
+			u_clock = 1;		/* 66Mhz */
+		else
+			u_clock = 0;		/* 33Mhz */
+
+		udma_enable |= (1 << devid);
+
+		/* Load the UDMA cycle time */
+		pci_read_config_word(dev, 0x4A, &udma_timing);
+		udma_timing &= ~(3 << (4 * devid));
+		udma_timing |= u_speed << (4 * devid);
+		pci_write_config_word(dev, 0x4A, udma_timing);
+
+		/* Load the clock selection */
+		pci_read_config_word(dev, 0x54, &ideconf);
+		ideconf &= ~(0x1001 << devid);
+		ideconf |= u_clock << devid;
+		pci_write_config_word(dev, 0x54, ideconf);
+	} else {
+		/*
+		 * MWDMA is driven by the PIO timings. We must also enable
+		 * IORDY unconditionally along with TIME1. PPE has already
+		 * been set when the PIO timing was set.
+		 */
+		unsigned int mwdma	= adev->dma_mode - XFER_MW_DMA_0;
+		unsigned int control;
+		u8 slave_data;
+		static const unsigned int needed_pio[3] = {
+			XFER_PIO_0, XFER_PIO_3, XFER_PIO_4
+		};
+		int pio = needed_pio[mwdma] - XFER_PIO_0;
+
+		control = 3;	/* IORDY|TIME1 */
+
+		/* If the drive MWDMA is faster than it can do PIO then
+		   we must force PIO into PIO0 */
+
+		if (adev->pio_mode < needed_pio[mwdma])
+			/* Enable DMA timing only */
+			control |= 8;	/* PIO cycles in PIO0 */
+
+		if (devid) {	/* Slave */
+			master_data &= 0xFF4F;  /* Mask out IORDY|TIME1|DMAONLY */
+			master_data |= control << 4;
+			pci_read_config_byte(dev, 0x44, &slave_data);
+			slave_data &= 0xF0;
+			/* Load the matching timing */
+			slave_data |= ((timings[pio][0] << 2) | timings[pio][1]) << (ap->port_no ? 4 : 0);
+			pci_write_config_byte(dev, 0x44, slave_data);
+		} else { 	/* Master */
+			master_data &= 0xCCF4;	/* Mask out IORDY|TIME1|DMAONLY
+						   and master timing bits */
+			master_data |= control;
+			master_data |=
+				(timings[pio][0] << 12) |
+				(timings[pio][1] << 8);
+		}
+		udma_enable &= ~(1 << devid);
+		pci_write_config_word(dev, 0x40, master_data);
+	}
+	pci_write_config_byte(dev, 0x48, udma_enable);
+}
+
+static const struct scsi_host_template it8213_sht = {
+	ATA_BMDMA_SHT(DRV_NAME),
+};
+
+
+static struct ata_port_operations it8213_ops = {
+	.inherits		= &ata_bmdma_port_ops,
+	.cable_detect		= it8213_cable_detect,
+	.set_piomode		= it8213_set_piomode,
+	.set_dmamode		= it8213_set_dmamode,
+	.reset.prereset		= it8213_pre_reset,
+};
+
+
+/**
+ *	it8213_init_one - Register 8213 ATA PCI device with kernel services
+ *	@pdev: PCI device to register
+ *	@ent: Entry in it8213_pci_tbl matching with @pdev
+ *
+ *	Called from kernel PCI layer.
+ *
+ *	LOCKING:
+ *	Inherited from PCI layer (may sleep).
+ *
+ *	RETURNS:
+ *	Zero on success, or -ERRNO value.
+ */
+
+static int it8213_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	static const struct ata_port_info info = {
+		.flags		= ATA_FLAG_SLAVE_POSS,
+		.pio_mask	= ATA_PIO4,
+		.mwdma_mask	= ATA_MWDMA12_ONLY,
+		.udma_mask	= ATA_UDMA6,
+		.port_ops	= &it8213_ops,
+	};
+	/* Current IT8213 stuff is single port */
+	const struct ata_port_info *ppi[] = { &info, &ata_dummy_port_info };
+
+	ata_print_version_once(&pdev->dev, DRV_VERSION);
+
+	return ata_pci_bmdma_init_one(pdev, ppi, &it8213_sht, NULL, 0);
+}
+
+static const struct pci_device_id it8213_pci_tbl[] = {
+	{ PCI_VDEVICE(ITE, PCI_DEVICE_ID_ITE_8213), },
+
+	{ }	/* terminate list */
+};
+
+static struct pci_driver it8213_pci_driver = {
+	.name			= DRV_NAME,
+	.id_table		= it8213_pci_tbl,
+	.probe			= it8213_init_one,
+	.remove			= ata_pci_remove_one,
+#ifdef CONFIG_PM_SLEEP
+	.suspend		= ata_pci_device_suspend,
+	.resume			= ata_pci_device_resume,
+#endif
+};
+
+module_pci_driver(it8213_pci_driver);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("SCSI low-level driver for the ITE 8213");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, it8213_pci_tbl);
+MODULE_VERSION(DRV_VERSION);