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>

4 files changed, 300 insertions, 0 deletions

diff --git a/arch/m68k/apollo/Makefile b/arch/m68k/apollo/Makefile
new file mode 100644
index 000000000..676c74b26
--- /dev/null
+++ b/arch/m68k/apollo/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for Linux arch/m68k/apollo source directory
+#
+
+obj-y		:= config.o dn_ints.o
diff --git a/arch/m68k/apollo/apollo.h b/arch/m68k/apollo/apollo.h
new file mode 100644
index 000000000..1fe9d856d
--- /dev/null
+++ b/arch/m68k/apollo/apollo.h
@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* dn_ints.c */
+void dn_init_IRQ(void);
diff --git a/arch/m68k/apollo/config.c b/arch/m68k/apollo/config.c
new file mode 100644
index 000000000..e324c5f67
--- /dev/null
+++ b/arch/m68k/apollo/config.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/rtc.h>
+#include <linux/interrupt.h>
+
+#include <asm/setup.h>
+#include <asm/bootinfo.h>
+#include <asm/bootinfo-apollo.h>
+#include <asm/byteorder.h>
+#include <asm/apollohw.h>
+#include <asm/irq.h>
+#include <asm/machdep.h>
+#include <asm/config.h>
+
+#include "apollo.h"
+
+u_long sio01_physaddr;
+u_long sio23_physaddr;
+u_long rtc_physaddr;
+u_long pica_physaddr;
+u_long picb_physaddr;
+u_long cpuctrl_physaddr;
+u_long timer_physaddr;
+u_long apollo_model;
+
+extern void dn_sched_init(void);
+extern int dn_dummy_hwclk(int, struct rtc_time *);
+static void dn_dummy_reset(void);
+#ifdef CONFIG_HEARTBEAT
+static void dn_heartbeat(int on);
+#endif
+static irqreturn_t dn_timer_int(int irq,void *);
+static void dn_get_model(char *model);
+static const char *apollo_models[] = {
+	[APOLLO_DN3000-APOLLO_DN3000] = "DN3000 (Otter)",
+	[APOLLO_DN3010-APOLLO_DN3000] = "DN3010 (Otter)",
+	[APOLLO_DN3500-APOLLO_DN3000] = "DN3500 (Cougar II)",
+	[APOLLO_DN4000-APOLLO_DN3000] = "DN4000 (Mink)",
+	[APOLLO_DN4500-APOLLO_DN3000] = "DN4500 (Roadrunner)"
+};
+
+int __init apollo_parse_bootinfo(const struct bi_record *record)
+{
+	int unknown = 0;
+	const void *data = record->data;
+
+	switch (be16_to_cpu(record->tag)) {
+	case BI_APOLLO_MODEL:
+		apollo_model = be32_to_cpup(data);
+		break;
+
+	default:
+		 unknown=1;
+	}
+
+	return unknown;
+}
+
+static void __init dn_setup_model(void)
+{
+	pr_info("Apollo hardware found: [%s]\n",
+		apollo_models[apollo_model - APOLLO_DN3000]);
+
+	switch(apollo_model) {
+		case APOLLO_UNKNOWN:
+			panic("Unknown apollo model");
+			break;
+		case APOLLO_DN3000:
+		case APOLLO_DN3010:
+			sio01_physaddr=SAU8_SIO01_PHYSADDR;
+			rtc_physaddr=SAU8_RTC_PHYSADDR;
+			pica_physaddr=SAU8_PICA;
+			picb_physaddr=SAU8_PICB;
+			cpuctrl_physaddr=SAU8_CPUCTRL;
+			timer_physaddr=SAU8_TIMER;
+			break;
+		case APOLLO_DN4000:
+			sio01_physaddr=SAU7_SIO01_PHYSADDR;
+			sio23_physaddr=SAU7_SIO23_PHYSADDR;
+			rtc_physaddr=SAU7_RTC_PHYSADDR;
+			pica_physaddr=SAU7_PICA;
+			picb_physaddr=SAU7_PICB;
+			cpuctrl_physaddr=SAU7_CPUCTRL;
+			timer_physaddr=SAU7_TIMER;
+			break;
+		case APOLLO_DN4500:
+			panic("Apollo model not yet supported");
+			break;
+		case APOLLO_DN3500:
+			sio01_physaddr=SAU7_SIO01_PHYSADDR;
+			sio23_physaddr=SAU7_SIO23_PHYSADDR;
+			rtc_physaddr=SAU7_RTC_PHYSADDR;
+			pica_physaddr=SAU7_PICA;
+			picb_physaddr=SAU7_PICB;
+			cpuctrl_physaddr=SAU7_CPUCTRL;
+			timer_physaddr=SAU7_TIMER;
+			break;
+		default:
+			panic("Undefined apollo model");
+			break;
+	}
+
+
+}
+
+static void dn_serial_print(const char *str)
+{
+    while (*str) {
+        if (*str == '\n') {
+            sio01.rhrb_thrb = (unsigned char)'\r';
+            while (!(sio01.srb_csrb & 0x4))
+                ;
+        }
+        sio01.rhrb_thrb = (unsigned char)*str++;
+        while (!(sio01.srb_csrb & 0x4))
+            ;
+    }
+}
+
+void __init config_apollo(void)
+{
+	int i;
+
+	dn_setup_model();
+
+	mach_sched_init=dn_sched_init; /* */
+	mach_init_IRQ=dn_init_IRQ;
+	mach_hwclk           = dn_dummy_hwclk; /* */
+	mach_reset	     = dn_dummy_reset;  /* */
+#ifdef CONFIG_HEARTBEAT
+	mach_heartbeat = dn_heartbeat;
+#endif
+	mach_get_model       = dn_get_model;
+
+	cpuctrl=0xaa00;
+
+	/* clear DMA translation table */
+	for(i=0;i<0x400;i++)
+		addr_xlat_map[i]=0;
+
+}
+
+irqreturn_t dn_timer_int(int irq, void *dev_id)
+{
+	unsigned char *at = (unsigned char *)apollo_timer;
+
+	legacy_timer_tick(1);
+	timer_heartbeat();
+
+	READ_ONCE(*(at + 3));
+	READ_ONCE(*(at + 5));
+
+	return IRQ_HANDLED;
+}
+
+void dn_sched_init(void)
+{
+	/* program timer 1 */
+	*(volatile unsigned char *)(apollo_timer + 3) = 0x01;
+	*(volatile unsigned char *)(apollo_timer + 1) = 0x40;
+	*(volatile unsigned char *)(apollo_timer + 5) = 0x09;
+	*(volatile unsigned char *)(apollo_timer + 7) = 0xc4;
+
+	/* enable IRQ of PIC B */
+	*(volatile unsigned char *)(pica+1)&=(~8);
+
+#if 0
+	pr_info("*(0x10803) %02x\n",
+		*(volatile unsigned char *)(apollo_timer + 0x3));
+	pr_info("*(0x10803) %02x\n",
+		*(volatile unsigned char *)(apollo_timer + 0x3));
+#endif
+
+	if (request_irq(IRQ_APOLLO, dn_timer_int, 0, "time", NULL))
+		pr_err("Couldn't register timer interrupt\n");
+}
+
+int dn_dummy_hwclk(int op, struct rtc_time *t) {
+
+
+  if(!op) { /* read */
+    t->tm_sec=rtc->second;
+    t->tm_min=rtc->minute;
+    t->tm_hour=rtc->hours;
+    t->tm_mday=rtc->day_of_month;
+    t->tm_wday=rtc->day_of_week;
+    t->tm_mon = rtc->month - 1;
+    t->tm_year=rtc->year;
+    if (t->tm_year < 70)
+	t->tm_year += 100;
+  } else {
+    rtc->second=t->tm_sec;
+    rtc->minute=t->tm_min;
+    rtc->hours=t->tm_hour;
+    rtc->day_of_month=t->tm_mday;
+    if(t->tm_wday!=-1)
+      rtc->day_of_week=t->tm_wday;
+    rtc->month = t->tm_mon + 1;
+    rtc->year = t->tm_year % 100;
+  }
+
+  return 0;
+
+}
+
+static void dn_dummy_reset(void)
+{
+  dn_serial_print("The end !\n");
+
+  for(;;);
+
+}
+
+static void dn_get_model(char *model)
+{
+    strcpy(model, "Apollo ");
+    if (apollo_model >= APOLLO_DN3000 && apollo_model <= APOLLO_DN4500)
+        strcat(model, apollo_models[apollo_model - APOLLO_DN3000]);
+}
+
+#ifdef CONFIG_HEARTBEAT
+static int dn_cpuctrl=0xff00;
+
+static void dn_heartbeat(int on) {
+
+	if(on) {
+		dn_cpuctrl&=~0x100;
+		cpuctrl=dn_cpuctrl;
+	}
+	else {
+		dn_cpuctrl&=~0x100;
+		dn_cpuctrl|=0x100;
+		cpuctrl=dn_cpuctrl;
+	}
+}
+#endif
+
diff --git a/arch/m68k/apollo/dn_ints.c b/arch/m68k/apollo/dn_ints.c
new file mode 100644
index 000000000..ba96a92f8
--- /dev/null
+++ b/arch/m68k/apollo/dn_ints.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include <asm/traps.h>
+#include <asm/apollohw.h>
+
+#include "apollo.h"
+
+static unsigned int apollo_irq_startup(struct irq_data *data)
+{
+	unsigned int irq = data->irq;
+
+	if (irq < 8)
+		*(volatile unsigned char *)(pica+1) &= ~(1 << irq);
+	else
+		*(volatile unsigned char *)(picb+1) &= ~(1 << (irq - 8));
+	return 0;
+}
+
+static void apollo_irq_shutdown(struct irq_data *data)
+{
+	unsigned int irq = data->irq;
+
+	if (irq < 8)
+		*(volatile unsigned char *)(pica+1) |= (1 << irq);
+	else
+		*(volatile unsigned char *)(picb+1) |= (1 << (irq - 8));
+}
+
+static void apollo_irq_eoi(struct irq_data *data)
+{
+	*(volatile unsigned char *)(pica) = 0x20;
+	*(volatile unsigned char *)(picb) = 0x20;
+}
+
+static struct irq_chip apollo_irq_chip = {
+	.name           = "apollo",
+	.irq_startup    = apollo_irq_startup,
+	.irq_shutdown   = apollo_irq_shutdown,
+	.irq_eoi	= apollo_irq_eoi,
+};
+
+
+void __init dn_init_IRQ(void)
+{
+	m68k_setup_user_interrupt(VEC_USER + 96, 16);
+	m68k_setup_irq_controller(&apollo_irq_chip, handle_fasteoi_irq,
+				  IRQ_APOLLO, 16);
+}