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, 128 insertions, 0 deletions

diff --git a/arch/mips/ath25/devices.c b/arch/mips/ath25/devices.c
new file mode 100644
index 000000000..301a90282
--- /dev/null
+++ b/arch/mips/ath25/devices.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/serial_8250.h>
+#include <linux/platform_device.h>
+#include <asm/bootinfo.h>
+
+#include <ath25_platform.h>
+#include "devices.h"
+#include "ar5312.h"
+#include "ar2315.h"
+
+struct ar231x_board_config ath25_board;
+enum ath25_soc_type ath25_soc = ATH25_SOC_UNKNOWN;
+
+static struct resource ath25_wmac0_res[] = {
+	{
+		.name = "wmac0_membase",
+		.flags = IORESOURCE_MEM,
+	},
+	{
+		.name = "wmac0_irq",
+		.flags = IORESOURCE_IRQ,
+	}
+};
+
+static struct resource ath25_wmac1_res[] = {
+	{
+		.name = "wmac1_membase",
+		.flags = IORESOURCE_MEM,
+	},
+	{
+		.name = "wmac1_irq",
+		.flags = IORESOURCE_IRQ,
+	}
+};
+
+static struct platform_device ath25_wmac[] = {
+	{
+		.id = 0,
+		.name = "ar231x-wmac",
+		.resource = ath25_wmac0_res,
+		.num_resources = ARRAY_SIZE(ath25_wmac0_res),
+		.dev.platform_data = &ath25_board,
+	},
+	{
+		.id = 1,
+		.name = "ar231x-wmac",
+		.resource = ath25_wmac1_res,
+		.num_resources = ARRAY_SIZE(ath25_wmac1_res),
+		.dev.platform_data = &ath25_board,
+	},
+};
+
+static const char * const soc_type_strings[] = {
+	[ATH25_SOC_AR5312] = "Atheros AR5312",
+	[ATH25_SOC_AR2312] = "Atheros AR2312",
+	[ATH25_SOC_AR2313] = "Atheros AR2313",
+	[ATH25_SOC_AR2315] = "Atheros AR2315",
+	[ATH25_SOC_AR2316] = "Atheros AR2316",
+	[ATH25_SOC_AR2317] = "Atheros AR2317",
+	[ATH25_SOC_AR2318] = "Atheros AR2318",
+	[ATH25_SOC_UNKNOWN] = "Atheros (unknown)",
+};
+
+const char *get_system_type(void)
+{
+	if ((ath25_soc >= ARRAY_SIZE(soc_type_strings)) ||
+	    !soc_type_strings[ath25_soc])
+		return soc_type_strings[ATH25_SOC_UNKNOWN];
+	return soc_type_strings[ath25_soc];
+}
+
+void __init ath25_serial_setup(u32 mapbase, int irq, unsigned int uartclk)
+{
+#ifdef CONFIG_SERIAL_8250_CONSOLE
+	struct uart_port s;
+
+	memset(&s, 0, sizeof(s));
+
+	s.flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_IOREMAP;
+	s.iotype = UPIO_MEM32;
+	s.irq = irq;
+	s.regshift = 2;
+	s.mapbase = mapbase;
+	s.uartclk = uartclk;
+
+	early_serial_setup(&s);
+#endif /* CONFIG_SERIAL_8250_CONSOLE */
+}
+
+int __init ath25_add_wmac(int nr, u32 base, int irq)
+{
+	struct resource *res;
+
+	ath25_wmac[nr].dev.platform_data = &ath25_board;
+	res = &ath25_wmac[nr].resource[0];
+	res->start = base;
+	res->end = base + 0x10000 - 1;
+	res++;
+	res->start = irq;
+	res->end = irq;
+	return platform_device_register(&ath25_wmac[nr]);
+}
+
+static int __init ath25_register_devices(void)
+{
+	if (is_ar5312())
+		ar5312_init_devices();
+	else
+		ar2315_init_devices();
+
+	return 0;
+}
+
+device_initcall(ath25_register_devices);
+
+static int __init ath25_arch_init(void)
+{
+	if (is_ar5312())
+		ar5312_arch_init();
+	else
+		ar2315_arch_init();
+
+	return 0;
+}
+
+arch_initcall(ath25_arch_init);