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, 298 insertions, 0 deletions

diff --git a/arch/arm/mach-hisi/hotplug.c b/arch/arm/mach-hisi/hotplug.c
new file mode 100644
index 000000000..f5655ad1c
--- /dev/null
+++ b/arch/arm/mach-hisi/hotplug.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013 Linaro Ltd.
+ * Copyright (c) 2013 HiSilicon Limited.
+ */
+
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+#include "core.h"
+
+/* Sysctrl registers in Hi3620 SoC */
+#define SCISOEN				0xc0
+#define SCISODIS			0xc4
+#define SCPERPWREN			0xd0
+#define SCPERPWRDIS			0xd4
+#define SCCPUCOREEN			0xf4
+#define SCCPUCOREDIS			0xf8
+#define SCPERCTRL0			0x200
+#define SCCPURSTEN			0x410
+#define SCCPURSTDIS			0x414
+
+/*
+ * bit definition in SCISOEN/SCPERPWREN/...
+ *
+ * CPU2_ISO_CTRL	(1 << 5)
+ * CPU3_ISO_CTRL	(1 << 6)
+ * ...
+ */
+#define CPU2_ISO_CTRL			(1 << 5)
+
+/*
+ * bit definition in SCPERCTRL0
+ *
+ * CPU0_WFI_MASK_CFG	(1 << 28)
+ * CPU1_WFI_MASK_CFG	(1 << 29)
+ * ...
+ */
+#define CPU0_WFI_MASK_CFG		(1 << 28)
+
+/*
+ * bit definition in SCCPURSTEN/...
+ *
+ * CPU0_SRST_REQ_EN	(1 << 0)
+ * CPU1_SRST_REQ_EN	(1 << 1)
+ * ...
+ */
+#define CPU0_HPM_SRST_REQ_EN		(1 << 22)
+#define CPU0_DBG_SRST_REQ_EN		(1 << 12)
+#define CPU0_NEON_SRST_REQ_EN		(1 << 4)
+#define CPU0_SRST_REQ_EN		(1 << 0)
+
+#define HIX5HD2_PERI_CRG20		0x50
+#define CRG20_CPU1_RESET		(1 << 17)
+
+#define HIX5HD2_PERI_PMC0		0x1000
+#define PMC0_CPU1_WAIT_MTCOMS_ACK	(1 << 8)
+#define PMC0_CPU1_PMC_ENABLE		(1 << 7)
+#define PMC0_CPU1_POWERDOWN		(1 << 3)
+
+#define HIP01_PERI9                    0x50
+#define PERI9_CPU1_RESET               (1 << 1)
+
+enum {
+	HI3620_CTRL,
+	ERROR_CTRL,
+};
+
+static void __iomem *ctrl_base;
+static int id;
+
+static void set_cpu_hi3620(int cpu, bool enable)
+{
+	u32 val = 0;
+
+	if (enable) {
+		/* MTCMOS set */
+		if ((cpu == 2) || (cpu == 3))
+			writel_relaxed(CPU2_ISO_CTRL << (cpu - 2),
+				       ctrl_base + SCPERPWREN);
+		udelay(100);
+
+		/* Enable core */
+		writel_relaxed(0x01 << cpu, ctrl_base + SCCPUCOREEN);
+
+		/* unreset */
+		val = CPU0_DBG_SRST_REQ_EN | CPU0_NEON_SRST_REQ_EN
+			| CPU0_SRST_REQ_EN;
+		writel_relaxed(val << cpu, ctrl_base + SCCPURSTDIS);
+		/* reset */
+		val |= CPU0_HPM_SRST_REQ_EN;
+		writel_relaxed(val << cpu, ctrl_base + SCCPURSTEN);
+
+		/* ISO disable */
+		if ((cpu == 2) || (cpu == 3))
+			writel_relaxed(CPU2_ISO_CTRL << (cpu - 2),
+				       ctrl_base + SCISODIS);
+		udelay(1);
+
+		/* WFI Mask */
+		val = readl_relaxed(ctrl_base + SCPERCTRL0);
+		val &= ~(CPU0_WFI_MASK_CFG << cpu);
+		writel_relaxed(val, ctrl_base + SCPERCTRL0);
+
+		/* Unreset */
+		val = CPU0_DBG_SRST_REQ_EN | CPU0_NEON_SRST_REQ_EN
+			| CPU0_SRST_REQ_EN | CPU0_HPM_SRST_REQ_EN;
+		writel_relaxed(val << cpu, ctrl_base + SCCPURSTDIS);
+	} else {
+		/* wfi mask */
+		val = readl_relaxed(ctrl_base + SCPERCTRL0);
+		val |= (CPU0_WFI_MASK_CFG << cpu);
+		writel_relaxed(val, ctrl_base + SCPERCTRL0);
+
+		/* disable core*/
+		writel_relaxed(0x01 << cpu, ctrl_base + SCCPUCOREDIS);
+
+		if ((cpu == 2) || (cpu == 3)) {
+			/* iso enable */
+			writel_relaxed(CPU2_ISO_CTRL << (cpu - 2),
+				       ctrl_base + SCISOEN);
+			udelay(1);
+		}
+
+		/* reset */
+		val = CPU0_DBG_SRST_REQ_EN | CPU0_NEON_SRST_REQ_EN
+			| CPU0_SRST_REQ_EN | CPU0_HPM_SRST_REQ_EN;
+		writel_relaxed(val << cpu, ctrl_base + SCCPURSTEN);
+
+		if ((cpu == 2) || (cpu == 3)) {
+			/* MTCMOS unset */
+			writel_relaxed(CPU2_ISO_CTRL << (cpu - 2),
+				       ctrl_base + SCPERPWRDIS);
+			udelay(100);
+		}
+	}
+}
+
+static int hi3xxx_hotplug_init(void)
+{
+	struct device_node *node;
+
+	node = of_find_compatible_node(NULL, NULL, "hisilicon,sysctrl");
+	if (!node) {
+		id = ERROR_CTRL;
+		return -ENOENT;
+	}
+
+	ctrl_base = of_iomap(node, 0);
+	of_node_put(node);
+	if (!ctrl_base) {
+		id = ERROR_CTRL;
+		return -ENOMEM;
+	}
+
+	id = HI3620_CTRL;
+	return 0;
+}
+
+void hi3xxx_set_cpu(int cpu, bool enable)
+{
+	if (!ctrl_base) {
+		if (hi3xxx_hotplug_init() < 0)
+			return;
+	}
+
+	if (id == HI3620_CTRL)
+		set_cpu_hi3620(cpu, enable);
+}
+
+static bool hix5hd2_hotplug_init(void)
+{
+	struct device_node *np;
+
+	np = of_find_compatible_node(NULL, NULL, "hisilicon,cpuctrl");
+	if (!np)
+		return false;
+
+	ctrl_base = of_iomap(np, 0);
+	of_node_put(np);
+	if (!ctrl_base)
+		return false;
+
+	return true;
+}
+
+void hix5hd2_set_cpu(int cpu, bool enable)
+{
+	u32 val = 0;
+
+	if (!ctrl_base)
+		if (!hix5hd2_hotplug_init())
+			BUG();
+
+	if (enable) {
+		/* power on cpu1 */
+		val = readl_relaxed(ctrl_base + HIX5HD2_PERI_PMC0);
+		val &= ~(PMC0_CPU1_WAIT_MTCOMS_ACK | PMC0_CPU1_POWERDOWN);
+		val |= PMC0_CPU1_PMC_ENABLE;
+		writel_relaxed(val, ctrl_base + HIX5HD2_PERI_PMC0);
+		/* unreset */
+		val = readl_relaxed(ctrl_base + HIX5HD2_PERI_CRG20);
+		val &= ~CRG20_CPU1_RESET;
+		writel_relaxed(val, ctrl_base + HIX5HD2_PERI_CRG20);
+	} else {
+		/* power down cpu1 */
+		val = readl_relaxed(ctrl_base + HIX5HD2_PERI_PMC0);
+		val |= PMC0_CPU1_PMC_ENABLE | PMC0_CPU1_POWERDOWN;
+		val &= ~PMC0_CPU1_WAIT_MTCOMS_ACK;
+		writel_relaxed(val, ctrl_base + HIX5HD2_PERI_PMC0);
+
+		/* reset */
+		val = readl_relaxed(ctrl_base + HIX5HD2_PERI_CRG20);
+		val |= CRG20_CPU1_RESET;
+		writel_relaxed(val, ctrl_base + HIX5HD2_PERI_CRG20);
+	}
+}
+
+void hip01_set_cpu(int cpu, bool enable)
+{
+	unsigned int temp;
+	struct device_node *np;
+
+	if (!ctrl_base) {
+		np = of_find_compatible_node(NULL, NULL, "hisilicon,hip01-sysctrl");
+		BUG_ON(!np);
+		ctrl_base = of_iomap(np, 0);
+		of_node_put(np);
+		BUG_ON(!ctrl_base);
+	}
+
+	if (enable) {
+		/* reset on CPU1  */
+		temp = readl_relaxed(ctrl_base + HIP01_PERI9);
+		temp |= PERI9_CPU1_RESET;
+		writel_relaxed(temp, ctrl_base + HIP01_PERI9);
+
+		udelay(50);
+
+		/* unreset on CPU1 */
+		temp = readl_relaxed(ctrl_base + HIP01_PERI9);
+		temp &= ~PERI9_CPU1_RESET;
+		writel_relaxed(temp, ctrl_base + HIP01_PERI9);
+	}
+}
+
+static inline void cpu_enter_lowpower(void)
+{
+	unsigned int v;
+
+	flush_cache_all();
+
+	/*
+	 * Turn off coherency and L1 D-cache
+	 */
+	asm volatile(
+	"	mrc	p15, 0, %0, c1, c0, 1\n"
+	"	bic	%0, %0, #0x40\n"
+	"	mcr	p15, 0, %0, c1, c0, 1\n"
+	"	mrc	p15, 0, %0, c1, c0, 0\n"
+	"	bic	%0, %0, #0x04\n"
+	"	mcr	p15, 0, %0, c1, c0, 0\n"
+	  : "=&r" (v)
+	  : "r" (0)
+	  : "cc");
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void hi3xxx_cpu_die(unsigned int cpu)
+{
+	cpu_enter_lowpower();
+	hi3xxx_set_cpu_jump(cpu, phys_to_virt(0));
+	cpu_do_idle();
+
+	/* We should have never returned from idle */
+	panic("cpu %d unexpectedly exit from shutdown\n", cpu);
+}
+
+int hi3xxx_cpu_kill(unsigned int cpu)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(50);
+
+	while (hi3xxx_get_cpu_jump(cpu))
+		if (time_after(jiffies, timeout))
+			return 0;
+	hi3xxx_set_cpu(cpu, false);
+	return 1;
+}
+
+void hix5hd2_cpu_die(unsigned int cpu)
+{
+	flush_cache_all();
+	hix5hd2_set_cpu(cpu, false);
+}
+#endif