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, 468 insertions, 0 deletions

diff --git a/drivers/parisc/eisa.c b/drivers/parisc/eisa.c
new file mode 100644
index 000000000..b5b5413bf
--- /dev/null
+++ b/drivers/parisc/eisa.c
@@ -0,0 +1,468 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eisa.c - provide support for EISA adapters in PA-RISC machines
+ *
+ * Copyright (c) 2001 Matthew Wilcox for Hewlett Packard
+ * Copyright (c) 2001 Daniel Engstrom <5116@telia.com>
+ *
+ * There are two distinct EISA adapters.  Mongoose is found in machines
+ * before the 712; then the Wax ASIC is used.  To complicate matters, the
+ * Wax ASIC also includes a PS/2 and RS-232 controller, but those are
+ * dealt with elsewhere; this file is concerned only with the EISA portions
+ * of Wax.
+ *
+ * HINT:
+ * -----
+ * To allow an ISA card to work properly in the EISA slot you need to
+ * set an edge trigger level. This may be done on the palo command line
+ * by adding the kernel parameter "eisa_irq_edge=n,n2,[...]]", with
+ * n and n2 as the irq levels you want to use.
+ *
+ * Example: "eisa_irq_edge=10,11" allows ISA cards to operate at
+ * irq levels 10 and 11.
+ */
+
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/eisa.h>
+
+#include <asm/byteorder.h>
+#include <asm/io.h>
+#include <asm/hardware.h>
+#include <asm/processor.h>
+#include <asm/parisc-device.h>
+#include <asm/delay.h>
+#include <asm/eisa_bus.h>
+#include <asm/eisa_eeprom.h>
+
+#include "iommu.h"
+
+#if 0
+#define EISA_DBG(msg, arg...) printk(KERN_DEBUG "eisa: " msg, ## arg)
+#else
+#define EISA_DBG(msg, arg...)
+#endif
+
+#define SNAKES_EEPROM_BASE_ADDR 0xF0810400
+#define MIRAGE_EEPROM_BASE_ADDR 0xF00C0400
+
+static DEFINE_SPINLOCK(eisa_irq_lock);
+
+void __iomem *eisa_eeprom_addr __read_mostly;
+
+/* We can only have one EISA adapter in the system because neither
+ * implementation can be flexed.
+ */
+static struct eisa_ba {
+	struct pci_hba_data	hba;
+	unsigned long eeprom_addr;
+	struct eisa_root_device root;
+} eisa_dev;
+
+/* Port ops */
+
+static inline unsigned long eisa_permute(unsigned short port)
+{
+	if (port & 0x300) {
+		return 0xfc000000 | ((port & 0xfc00) >> 6)
+			| ((port & 0x3f8) << 9) | (port & 7);
+	} else {
+		return 0xfc000000 | port;
+	}
+}
+
+unsigned char eisa_in8(unsigned short port)
+{
+	if (EISA_bus)
+		return gsc_readb(eisa_permute(port));
+	return 0xff;
+}
+
+unsigned short eisa_in16(unsigned short port)
+{
+	if (EISA_bus)
+		return le16_to_cpu(gsc_readw(eisa_permute(port)));
+	return 0xffff;
+}
+
+unsigned int eisa_in32(unsigned short port)
+{
+	if (EISA_bus)
+		return le32_to_cpu(gsc_readl(eisa_permute(port)));
+	return 0xffffffff;
+}
+
+void eisa_out8(unsigned char data, unsigned short port)
+{
+	if (EISA_bus)
+		gsc_writeb(data, eisa_permute(port));
+}
+
+void eisa_out16(unsigned short data, unsigned short port)
+{
+	if (EISA_bus)
+		gsc_writew(cpu_to_le16(data), eisa_permute(port));
+}
+
+void eisa_out32(unsigned int data, unsigned short port)
+{
+	if (EISA_bus)
+		gsc_writel(cpu_to_le32(data), eisa_permute(port));
+}
+
+#ifndef CONFIG_PCI
+/* We call these directly without PCI.  See asm/io.h. */
+EXPORT_SYMBOL(eisa_in8);
+EXPORT_SYMBOL(eisa_in16);
+EXPORT_SYMBOL(eisa_in32);
+EXPORT_SYMBOL(eisa_out8);
+EXPORT_SYMBOL(eisa_out16);
+EXPORT_SYMBOL(eisa_out32);
+#endif
+
+/* Interrupt handling */
+
+/* cached interrupt mask registers */
+static int master_mask;
+static int slave_mask;
+
+/* the trig level can be set with the
+ * eisa_irq_edge=n,n,n commandline parameter
+ * We should really read this from the EEPROM
+ * in the furure.
+ */
+/* irq 13,8,2,1,0 must be edge */
+static unsigned int eisa_irq_level __read_mostly; /* default to edge triggered */
+
+
+/* called by free irq */
+static void eisa_mask_irq(struct irq_data *d)
+{
+	unsigned int irq = d->irq;
+	unsigned long flags;
+
+	EISA_DBG("disable irq %d\n", irq);
+	/* just mask for now */
+	spin_lock_irqsave(&eisa_irq_lock, flags);
+        if (irq & 8) {
+		slave_mask |= (1 << (irq&7));
+		eisa_out8(slave_mask, 0xa1);
+	} else {
+		master_mask |= (1 << (irq&7));
+		eisa_out8(master_mask, 0x21);
+	}
+	spin_unlock_irqrestore(&eisa_irq_lock, flags);
+	EISA_DBG("pic0 mask %02x\n", eisa_in8(0x21));
+	EISA_DBG("pic1 mask %02x\n", eisa_in8(0xa1));
+}
+
+/* called by request irq */
+static void eisa_unmask_irq(struct irq_data *d)
+{
+	unsigned int irq = d->irq;
+	unsigned long flags;
+	EISA_DBG("enable irq %d\n", irq);
+
+	spin_lock_irqsave(&eisa_irq_lock, flags);
+        if (irq & 8) {
+		slave_mask &= ~(1 << (irq&7));
+		eisa_out8(slave_mask, 0xa1);
+	} else {
+		master_mask &= ~(1 << (irq&7));
+		eisa_out8(master_mask, 0x21);
+	}
+	spin_unlock_irqrestore(&eisa_irq_lock, flags);
+	EISA_DBG("pic0 mask %02x\n", eisa_in8(0x21));
+	EISA_DBG("pic1 mask %02x\n", eisa_in8(0xa1));
+}
+
+static struct irq_chip eisa_interrupt_type = {
+	.name		=	"EISA",
+	.irq_unmask	=	eisa_unmask_irq,
+	.irq_mask	=	eisa_mask_irq,
+};
+
+static irqreturn_t eisa_irq(int wax_irq, void *intr_dev)
+{
+	int irq = gsc_readb(0xfc01f000); /* EISA supports 16 irqs */
+	unsigned long flags;
+
+	spin_lock_irqsave(&eisa_irq_lock, flags);
+	/* read IRR command */
+	eisa_out8(0x0a, 0x20);
+	eisa_out8(0x0a, 0xa0);
+
+	EISA_DBG("irq IAR %02x 8259-1 irr %02x 8259-2 irr %02x\n",
+		   irq, eisa_in8(0x20), eisa_in8(0xa0));
+
+	/* read ISR command */
+	eisa_out8(0x0a, 0x20);
+	eisa_out8(0x0a, 0xa0);
+	EISA_DBG("irq 8259-1 isr %02x imr %02x 8259-2 isr %02x imr %02x\n",
+		 eisa_in8(0x20), eisa_in8(0x21), eisa_in8(0xa0), eisa_in8(0xa1));
+
+	irq &= 0xf;
+
+	/* mask irq and write eoi */
+	if (irq & 8) {
+		slave_mask |= (1 << (irq&7));
+		eisa_out8(slave_mask, 0xa1);
+		eisa_out8(0x60 | (irq&7),0xa0);/* 'Specific EOI' to slave */
+		eisa_out8(0x62, 0x20);	/* 'Specific EOI' to master-IRQ2 */
+
+	} else {
+		master_mask |= (1 << (irq&7));
+		eisa_out8(master_mask, 0x21);
+		eisa_out8(0x60|irq, 0x20);	/* 'Specific EOI' to master */
+	}
+	spin_unlock_irqrestore(&eisa_irq_lock, flags);
+
+	generic_handle_irq(irq);
+
+	spin_lock_irqsave(&eisa_irq_lock, flags);
+	/* unmask */
+        if (irq & 8) {
+		slave_mask &= ~(1 << (irq&7));
+		eisa_out8(slave_mask, 0xa1);
+	} else {
+		master_mask &= ~(1 << (irq&7));
+		eisa_out8(master_mask, 0x21);
+	}
+	spin_unlock_irqrestore(&eisa_irq_lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t dummy_irq2_handler(int _, void *dev)
+{
+	printk(KERN_ALERT "eisa: uhh, irq2?\n");
+	return IRQ_HANDLED;
+}
+
+static void init_eisa_pic(void)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&eisa_irq_lock, flags);
+
+	eisa_out8(0xff, 0x21); /* mask during init */
+	eisa_out8(0xff, 0xa1); /* mask during init */
+
+	/* master pic */
+	eisa_out8(0x11, 0x20); /* ICW1 */
+	eisa_out8(0x00, 0x21); /* ICW2 */
+	eisa_out8(0x04, 0x21); /* ICW3 */
+	eisa_out8(0x01, 0x21); /* ICW4 */
+	eisa_out8(0x40, 0x20); /* OCW2 */
+
+	/* slave pic */
+	eisa_out8(0x11, 0xa0); /* ICW1 */
+	eisa_out8(0x08, 0xa1); /* ICW2 */
+	eisa_out8(0x02, 0xa1); /* ICW3 */
+	eisa_out8(0x01, 0xa1); /* ICW4 */
+	eisa_out8(0x40, 0xa0); /* OCW2 */
+
+	udelay(100);
+
+	slave_mask = 0xff;
+	master_mask = 0xfb;
+	eisa_out8(slave_mask, 0xa1); /* OCW1 */
+	eisa_out8(master_mask, 0x21); /* OCW1 */
+
+	/* setup trig level */
+	EISA_DBG("EISA edge/level %04x\n", eisa_irq_level);
+
+	eisa_out8(eisa_irq_level&0xff, 0x4d0); /* Set all irq's to edge  */
+	eisa_out8((eisa_irq_level >> 8) & 0xff, 0x4d1);
+
+	EISA_DBG("pic0 mask %02x\n", eisa_in8(0x21));
+	EISA_DBG("pic1 mask %02x\n", eisa_in8(0xa1));
+	EISA_DBG("pic0 edge/level %02x\n", eisa_in8(0x4d0));
+	EISA_DBG("pic1 edge/level %02x\n", eisa_in8(0x4d1));
+
+	spin_unlock_irqrestore(&eisa_irq_lock, flags);
+}
+
+/* Device initialisation */
+
+#define is_mongoose(dev) (dev->id.sversion == 0x00076)
+
+static int __init eisa_probe(struct parisc_device *dev)
+{
+	int i, result;
+
+	char *name = is_mongoose(dev) ? "Mongoose" : "Wax";
+
+	printk(KERN_INFO "%s EISA Adapter found at 0x%08lx\n",
+		name, (unsigned long)dev->hpa.start);
+
+	eisa_dev.hba.dev = dev;
+	eisa_dev.hba.iommu = ccio_get_iommu(dev);
+
+	eisa_dev.hba.lmmio_space.name = "EISA";
+	eisa_dev.hba.lmmio_space.start = F_EXTEND(0xfc000000);
+	eisa_dev.hba.lmmio_space.end = F_EXTEND(0xffbfffff);
+	eisa_dev.hba.lmmio_space.flags = IORESOURCE_MEM;
+	result = ccio_request_resource(dev, &eisa_dev.hba.lmmio_space);
+	if (result < 0) {
+		printk(KERN_ERR "EISA: failed to claim EISA Bus address space!\n");
+		return result;
+	}
+	eisa_dev.hba.io_space.name = "EISA";
+	eisa_dev.hba.io_space.start = 0;
+	eisa_dev.hba.io_space.end = 0xffff;
+	eisa_dev.hba.lmmio_space.flags = IORESOURCE_IO;
+	result = request_resource(&ioport_resource, &eisa_dev.hba.io_space);
+	if (result < 0) {
+		printk(KERN_ERR "EISA: failed to claim EISA Bus port space!\n");
+		return result;
+	}
+	pcibios_register_hba(&eisa_dev.hba);
+
+	result = request_irq(dev->irq, eisa_irq, IRQF_SHARED, "EISA", &eisa_dev);
+	if (result) {
+		printk(KERN_ERR "EISA: request_irq failed!\n");
+		goto error_release;
+	}
+
+	/* Reserve IRQ2 */
+	if (request_irq(2, dummy_irq2_handler, 0, "cascade", NULL))
+		pr_err("Failed to request irq 2 (cascade)\n");
+	for (i = 0; i < 16; i++) {
+		irq_set_chip_and_handler(i, &eisa_interrupt_type,
+					 handle_simple_irq);
+	}
+
+	EISA_bus = 1;
+
+	if (dev->num_addrs) {
+		/* newer firmware hand out the eeprom address */
+		eisa_dev.eeprom_addr = dev->addr[0];
+	} else {
+		/* old firmware, need to figure out the box */
+		if (is_mongoose(dev)) {
+			eisa_dev.eeprom_addr = SNAKES_EEPROM_BASE_ADDR;
+		} else {
+			eisa_dev.eeprom_addr = MIRAGE_EEPROM_BASE_ADDR;
+		}
+	}
+	eisa_eeprom_addr = ioremap(eisa_dev.eeprom_addr, HPEE_MAX_LENGTH);
+	if (!eisa_eeprom_addr) {
+		result = -ENOMEM;
+		printk(KERN_ERR "EISA: ioremap failed!\n");
+		goto error_free_irq;
+	}
+	result = eisa_enumerator(eisa_dev.eeprom_addr, &eisa_dev.hba.io_space,
+			&eisa_dev.hba.lmmio_space);
+	init_eisa_pic();
+
+	if (result >= 0) {
+		/* FIXME : Don't enumerate the bus twice. */
+		eisa_dev.root.dev = &dev->dev;
+		dev_set_drvdata(&dev->dev, &eisa_dev.root);
+		eisa_dev.root.bus_base_addr = 0;
+		eisa_dev.root.res = &eisa_dev.hba.io_space;
+		eisa_dev.root.slots = result;
+		eisa_dev.root.dma_mask = 0xffffffff; /* wild guess */
+		if (eisa_root_register (&eisa_dev.root)) {
+			printk(KERN_ERR "EISA: Failed to register EISA root\n");
+			result = -ENOMEM;
+			goto error_iounmap;
+		}
+	}
+
+	return 0;
+
+error_iounmap:
+	iounmap(eisa_eeprom_addr);
+error_free_irq:
+	free_irq(dev->irq, &eisa_dev);
+error_release:
+	release_resource(&eisa_dev.hba.io_space);
+	return result;
+}
+
+static const struct parisc_device_id eisa_tbl[] __initconst = {
+	{ HPHW_BA, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x00076 }, /* Mongoose */
+	{ HPHW_BA, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x00090 }, /* Wax EISA */
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE(parisc, eisa_tbl);
+
+static struct parisc_driver eisa_driver __refdata = {
+	.name =		"eisa_ba",
+	.id_table =	eisa_tbl,
+	.probe =	eisa_probe,
+};
+
+static int __init parisc_eisa_init(void)
+{
+	return register_parisc_driver(&eisa_driver);
+}
+arch_initcall(parisc_eisa_init);
+
+
+static unsigned int eisa_irq_configured;
+void eisa_make_irq_level(int num)
+{
+	if (eisa_irq_configured& (1<<num)) {
+		printk(KERN_WARNING
+		       "IRQ %d polarity configured twice (last to level)\n",
+		       num);
+	}
+	eisa_irq_level |= (1<<num); /* set the corresponding bit */
+	eisa_irq_configured |= (1<<num); /* set the corresponding bit */
+}
+
+void eisa_make_irq_edge(int num)
+{
+	if (eisa_irq_configured& (1<<num)) {
+		printk(KERN_WARNING
+		       "IRQ %d polarity configured twice (last to edge)\n",
+		       num);
+	}
+	eisa_irq_level &= ~(1<<num); /* clear the corresponding bit */
+	eisa_irq_configured |= (1<<num); /* set the corresponding bit */
+}
+
+static int __init eisa_irq_setup(char *str)
+{
+	char *cur = str;
+	int val;
+
+	EISA_DBG("IRQ setup\n");
+	while (cur != NULL) {
+		char *pe;
+
+		val = (int) simple_strtoul(cur, &pe, 0);
+		if (val > 15 || val < 0) {
+			printk(KERN_ERR "eisa: EISA irq value are 0-15\n");
+			cur = strchr(cur, ',');
+			if (cur)
+				cur++;
+			else
+				break;
+			continue;
+		}
+		if (val == 2) {
+			val = 9;
+		}
+		eisa_make_irq_edge(val); /* clear the corresponding bit */
+		EISA_DBG("setting IRQ %d to edge-triggered mode\n", val);
+
+		if ((cur = strchr(cur, ','))) {
+			cur++;
+		} else {
+			break;
+		}
+	}
+	return 1;
+}
+
+__setup("eisa_irq_edge=", eisa_irq_setup);
+