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, 365 insertions, 0 deletions

diff --git a/drivers/pci/controller/pci-thunder-ecam.c b/drivers/pci/controller/pci-thunder-ecam.c
new file mode 100644
index 000000000..b5b4a958e
--- /dev/null
+++ b/drivers/pci/controller/pci-thunder-ecam.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015, 2016 Cavium, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/of_pci.h>
+#include <linux/of.h>
+#include <linux/pci-ecam.h>
+#include <linux/platform_device.h>
+
+#include "pci-host-common.h"
+
+#if defined(CONFIG_PCI_HOST_THUNDER_ECAM) || (defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS))
+
+static void set_val(u32 v, int where, int size, u32 *val)
+{
+	int shift = (where & 3) * 8;
+
+	pr_debug("set_val %04x: %08x\n", (unsigned int)(where & ~3), v);
+	v >>= shift;
+	if (size == 1)
+		v &= 0xff;
+	else if (size == 2)
+		v &= 0xffff;
+	*val = v;
+}
+
+static int handle_ea_bar(u32 e0, int bar, struct pci_bus *bus,
+			 unsigned int devfn, int where, int size, u32 *val)
+{
+	void __iomem *addr;
+	u32 v;
+
+	/* Entries are 16-byte aligned; bits[2,3] select word in entry */
+	int where_a = where & 0xc;
+
+	if (where_a == 0) {
+		set_val(e0, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	if (where_a == 0x4) {
+		addr = bus->ops->map_bus(bus, devfn, bar); /* BAR 0 */
+		if (!addr)
+			return PCIBIOS_DEVICE_NOT_FOUND;
+
+		v = readl(addr);
+		v &= ~0xf;
+		v |= 2; /* EA entry-1. Base-L */
+		set_val(v, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	if (where_a == 0x8) {
+		u32 barl_orig;
+		u32 barl_rb;
+
+		addr = bus->ops->map_bus(bus, devfn, bar); /* BAR 0 */
+		if (!addr)
+			return PCIBIOS_DEVICE_NOT_FOUND;
+
+		barl_orig = readl(addr + 0);
+		writel(0xffffffff, addr + 0);
+		barl_rb = readl(addr + 0);
+		writel(barl_orig, addr + 0);
+		/* zeros in unsettable bits */
+		v = ~barl_rb & ~3;
+		v |= 0xc; /* EA entry-2. Offset-L */
+		set_val(v, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	if (where_a == 0xc) {
+		addr = bus->ops->map_bus(bus, devfn, bar + 4); /* BAR 1 */
+		if (!addr)
+			return PCIBIOS_DEVICE_NOT_FOUND;
+
+		v = readl(addr); /* EA entry-3. Base-H */
+		set_val(v, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	return PCIBIOS_DEVICE_NOT_FOUND;
+}
+
+static int thunder_ecam_p2_config_read(struct pci_bus *bus, unsigned int devfn,
+				       int where, int size, u32 *val)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+	int where_a = where & ~3;
+	void __iomem *addr;
+	u32 node_bits;
+	u32 v;
+
+	/* EA Base[63:32] may be missing some bits ... */
+	switch (where_a) {
+	case 0xa8:
+	case 0xbc:
+	case 0xd0:
+	case 0xe4:
+		break;
+	default:
+		return pci_generic_config_read(bus, devfn, where, size, val);
+	}
+
+	addr = bus->ops->map_bus(bus, devfn, where_a);
+	if (!addr)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	v = readl(addr);
+
+	/*
+	 * Bit 44 of the 64-bit Base must match the same bit in
+	 * the config space access window.  Since we are working with
+	 * the high-order 32 bits, shift everything down by 32 bits.
+	 */
+	node_bits = upper_32_bits(cfg->res.start) & (1 << 12);
+
+	v |= node_bits;
+	set_val(v, where, size, val);
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int thunder_ecam_config_read(struct pci_bus *bus, unsigned int devfn,
+				    int where, int size, u32 *val)
+{
+	u32 v;
+	u32 vendor_device;
+	u32 class_rev;
+	void __iomem *addr;
+	int cfg_type;
+	int where_a = where & ~3;
+
+	addr = bus->ops->map_bus(bus, devfn, 0xc);
+	if (!addr)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	v = readl(addr);
+
+	/* Check for non type-00 header */
+	cfg_type = (v >> 16) & 0x7f;
+
+	addr = bus->ops->map_bus(bus, devfn, 8);
+	if (!addr)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	class_rev = readl(addr);
+	if (class_rev == 0xffffffff)
+		goto no_emulation;
+
+	if ((class_rev & 0xff) >= 8) {
+		/* Pass-2 handling */
+		if (cfg_type)
+			goto no_emulation;
+		return thunder_ecam_p2_config_read(bus, devfn, where,
+						   size, val);
+	}
+
+	/*
+	 * All BARs have fixed addresses specified by the EA
+	 * capability; they must return zero on read.
+	 */
+	if (cfg_type == 0 &&
+	    ((where >= 0x10 && where < 0x2c) ||
+	     (where >= 0x1a4 && where < 0x1bc))) {
+		/* BAR or SR-IOV BAR */
+		*val = 0;
+		return PCIBIOS_SUCCESSFUL;
+	}
+
+	addr = bus->ops->map_bus(bus, devfn, 0);
+	if (!addr)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	vendor_device = readl(addr);
+	if (vendor_device == 0xffffffff)
+		goto no_emulation;
+
+	pr_debug("%04x:%04x - Fix pass#: %08x, where: %03x, devfn: %03x\n",
+		 vendor_device & 0xffff, vendor_device >> 16, class_rev,
+		 (unsigned int)where, devfn);
+
+	/* Check for non type-00 header */
+	if (cfg_type == 0) {
+		bool has_msix;
+		bool is_nic = (vendor_device == 0xa01e177d);
+		bool is_tns = (vendor_device == 0xa01f177d);
+
+		addr = bus->ops->map_bus(bus, devfn, 0x70);
+		if (!addr)
+			return PCIBIOS_DEVICE_NOT_FOUND;
+
+		/* E_CAP */
+		v = readl(addr);
+		has_msix = (v & 0xff00) != 0;
+
+		if (!has_msix && where_a == 0x70) {
+			v |= 0xbc00; /* next capability is EA at 0xbc */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xb0) {
+			addr = bus->ops->map_bus(bus, devfn, where_a);
+			if (!addr)
+				return PCIBIOS_DEVICE_NOT_FOUND;
+
+			v = readl(addr);
+			if (v & 0xff00)
+				pr_err("Bad MSI-X cap header: %08x\n", v);
+			v |= 0xbc00; /* next capability is EA at 0xbc */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xbc) {
+			if (is_nic)
+				v = 0x40014; /* EA last in chain, 4 entries */
+			else if (is_tns)
+				v = 0x30014; /* EA last in chain, 3 entries */
+			else if (has_msix)
+				v = 0x20014; /* EA last in chain, 2 entries */
+			else
+				v = 0x10014; /* EA last in chain, 1 entry */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a >= 0xc0 && where_a < 0xd0)
+			/* EA entry-0. PP=0, BAR0 Size:3 */
+			return handle_ea_bar(0x80ff0003,
+					     0x10, bus, devfn, where,
+					     size, val);
+		if (where_a >= 0xd0 && where_a < 0xe0 && has_msix)
+			 /* EA entry-1. PP=0, BAR4 Size:3 */
+			return handle_ea_bar(0x80ff0043,
+					     0x20, bus, devfn, where,
+					     size, val);
+		if (where_a >= 0xe0 && where_a < 0xf0 && is_tns)
+			/* EA entry-2. PP=0, BAR2, Size:3 */
+			return handle_ea_bar(0x80ff0023,
+					     0x18, bus, devfn, where,
+					     size, val);
+		if (where_a >= 0xe0 && where_a < 0xf0 && is_nic)
+			/* EA entry-2. PP=4, VF_BAR0 (9), Size:3 */
+			return handle_ea_bar(0x80ff0493,
+					     0x1a4, bus, devfn, where,
+					     size, val);
+		if (where_a >= 0xf0 && where_a < 0x100 && is_nic)
+			/* EA entry-3. PP=4, VF_BAR4 (d), Size:3 */
+			return handle_ea_bar(0x80ff04d3,
+					     0x1b4, bus, devfn, where,
+					     size, val);
+	} else if (cfg_type == 1) {
+		bool is_rsl_bridge = devfn == 0x08;
+		bool is_rad_bridge = devfn == 0xa0;
+		bool is_zip_bridge = devfn == 0xa8;
+		bool is_dfa_bridge = devfn == 0xb0;
+		bool is_nic_bridge = devfn == 0x10;
+
+		if (where_a == 0x70) {
+			addr = bus->ops->map_bus(bus, devfn, where_a);
+			if (!addr)
+				return PCIBIOS_DEVICE_NOT_FOUND;
+
+			v = readl(addr);
+			if (v & 0xff00)
+				pr_err("Bad PCIe cap header: %08x\n", v);
+			v |= 0xbc00; /* next capability is EA at 0xbc */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xbc) {
+			if (is_nic_bridge)
+				v = 0x10014; /* EA last in chain, 1 entry */
+			else
+				v = 0x00014; /* EA last in chain, no entries */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xc0) {
+			if (is_rsl_bridge || is_nic_bridge)
+				v = 0x0101; /* subordinate:secondary = 1:1 */
+			else if (is_rad_bridge)
+				v = 0x0202; /* subordinate:secondary = 2:2 */
+			else if (is_zip_bridge)
+				v = 0x0303; /* subordinate:secondary = 3:3 */
+			else if (is_dfa_bridge)
+				v = 0x0404; /* subordinate:secondary = 4:4 */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xc4 && is_nic_bridge) {
+			/* Enabled, not-Write, SP=ff, PP=05, BEI=6, ES=4 */
+			v = 0x80ff0564;
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xc8 && is_nic_bridge) {
+			v = 0x00000002; /* Base-L 64-bit */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xcc && is_nic_bridge) {
+			v = 0xfffffffe; /* MaxOffset-L 64-bit */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xd0 && is_nic_bridge) {
+			v = 0x00008430; /* NIC Base-H */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xd4 && is_nic_bridge) {
+			v = 0x0000000f; /* MaxOffset-H */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+	}
+no_emulation:
+	return pci_generic_config_read(bus, devfn, where, size, val);
+}
+
+static int thunder_ecam_config_write(struct pci_bus *bus, unsigned int devfn,
+				     int where, int size, u32 val)
+{
+	/*
+	 * All BARs have fixed addresses; ignore BAR writes so they
+	 * don't get corrupted.
+	 */
+	if ((where >= 0x10 && where < 0x2c) ||
+	    (where >= 0x1a4 && where < 0x1bc))
+		/* BAR or SR-IOV BAR */
+		return PCIBIOS_SUCCESSFUL;
+
+	return pci_generic_config_write(bus, devfn, where, size, val);
+}
+
+const struct pci_ecam_ops pci_thunder_ecam_ops = {
+	.pci_ops	= {
+		.map_bus        = pci_ecam_map_bus,
+		.read           = thunder_ecam_config_read,
+		.write          = thunder_ecam_config_write,
+	}
+};
+
+#ifdef CONFIG_PCI_HOST_THUNDER_ECAM
+
+static const struct of_device_id thunder_ecam_of_match[] = {
+	{
+		.compatible = "cavium,pci-host-thunder-ecam",
+		.data = &pci_thunder_ecam_ops,
+	},
+	{ },
+};
+
+static struct platform_driver thunder_ecam_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = thunder_ecam_of_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe = pci_host_common_probe,
+};
+builtin_platform_driver(thunder_ecam_driver);
+
+#endif
+#endif