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, 152 insertions, 0 deletions

diff --git a/drivers/xen/acpi.c b/drivers/xen/acpi.c
new file mode 100644
index 000000000..eab28cfe9
--- /dev/null
+++ b/drivers/xen/acpi.c
@@ -0,0 +1,152 @@
+/******************************************************************************
+ * acpi.c
+ * acpi file for domain 0 kernel
+ *
+ * Copyright (c) 2011 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ * Copyright (c) 2011 Yu Ke ke.yu@intel.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/pci.h>
+#include <xen/acpi.h>
+#include <xen/interface/platform.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+static int xen_acpi_notify_hypervisor_state(u8 sleep_state,
+					    u32 val_a, u32 val_b,
+					    bool extended)
+{
+	unsigned int bits = extended ? 8 : 16;
+
+	struct xen_platform_op op = {
+		.cmd = XENPF_enter_acpi_sleep,
+		.interface_version = XENPF_INTERFACE_VERSION,
+		.u.enter_acpi_sleep = {
+			.val_a = (u16)val_a,
+			.val_b = (u16)val_b,
+			.sleep_state = sleep_state,
+			.flags = extended ? XENPF_ACPI_SLEEP_EXTENDED : 0,
+		},
+	};
+
+	if (WARN((val_a & (~0 << bits)) || (val_b & (~0 << bits)),
+		 "Using more than %u bits of sleep control values %#x/%#x!"
+		 "Email xen-devel@lists.xen.org - Thank you.\n", \
+		 bits, val_a, val_b))
+		return -1;
+
+	HYPERVISOR_platform_op(&op);
+	return 1;
+}
+
+int xen_acpi_notify_hypervisor_sleep(u8 sleep_state,
+				     u32 pm1a_cnt, u32 pm1b_cnt)
+{
+	return xen_acpi_notify_hypervisor_state(sleep_state, pm1a_cnt,
+						pm1b_cnt, false);
+}
+
+int xen_acpi_notify_hypervisor_extended_sleep(u8 sleep_state,
+				     u32 val_a, u32 val_b)
+{
+	return xen_acpi_notify_hypervisor_state(sleep_state, val_a,
+						val_b, true);
+}
+
+struct acpi_prt_entry {
+	struct acpi_pci_id      id;
+	u8                      pin;
+	acpi_handle             link;
+	u32                     index;
+};
+
+int xen_acpi_get_gsi_info(struct pci_dev *dev,
+						  int *gsi_out,
+						  int *trigger_out,
+						  int *polarity_out)
+{
+	u32 gsi;
+	u8 pin;
+	struct acpi_prt_entry *entry;
+	int trigger = ACPI_LEVEL_SENSITIVE;
+	int ret, polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ?
+				      ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
+
+	if (!dev || !gsi_out || !trigger_out || !polarity_out)
+		return -EINVAL;
+
+	pin = dev->pin;
+	if (!pin)
+		return -EINVAL;
+
+	entry = acpi_pci_irq_lookup(dev, pin);
+	if (entry) {
+		ret = 0;
+		if (entry->link)
+			ret = acpi_pci_link_allocate_irq(entry->link,
+							 entry->index,
+							 &trigger, &polarity,
+							 NULL, &gsi);
+		else
+			gsi = entry->index;
+	} else
+		ret = -ENODEV;
+
+	if (ret < 0)
+		return -EINVAL;
+
+	*gsi_out = gsi;
+	*trigger_out = trigger;
+	*polarity_out = polarity;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xen_acpi_get_gsi_info);
+
+static get_gsi_from_sbdf_t get_gsi_from_sbdf;
+static DEFINE_RWLOCK(get_gsi_from_sbdf_lock);
+
+void xen_acpi_register_get_gsi_func(get_gsi_from_sbdf_t func)
+{
+	write_lock(&get_gsi_from_sbdf_lock);
+	get_gsi_from_sbdf = func;
+	write_unlock(&get_gsi_from_sbdf_lock);
+}
+EXPORT_SYMBOL_GPL(xen_acpi_register_get_gsi_func);
+
+int xen_acpi_get_gsi_from_sbdf(u32 sbdf)
+{
+	int ret = -EOPNOTSUPP;
+
+	read_lock(&get_gsi_from_sbdf_lock);
+	if (get_gsi_from_sbdf)
+		ret = get_gsi_from_sbdf(sbdf);
+	read_unlock(&get_gsi_from_sbdf_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xen_acpi_get_gsi_from_sbdf);