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, 149 insertions, 0 deletions

diff --git a/arch/mips/ath79/common.c b/arch/mips/ath79/common.c
new file mode 100644
index 000000000..137abbc65
--- /dev/null
+++ b/arch/mips/ath79/common.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Atheros AR71XX/AR724X/AR913X common routines
+ *
+ *  Copyright (C) 2010-2011 Jaiganesh Narayanan <jnarayanan@atheros.com>
+ *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  Parts of this file are based on Atheros' 2.6.15/2.6.31 BSP
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include "common.h"
+
+static DEFINE_SPINLOCK(ath79_device_reset_lock);
+
+u32 ath79_cpu_freq;
+EXPORT_SYMBOL_GPL(ath79_cpu_freq);
+
+u32 ath79_ahb_freq;
+EXPORT_SYMBOL_GPL(ath79_ahb_freq);
+
+u32 ath79_ddr_freq;
+EXPORT_SYMBOL_GPL(ath79_ddr_freq);
+
+enum ath79_soc_type ath79_soc;
+unsigned int ath79_soc_rev;
+
+void __iomem *ath79_pll_base;
+void __iomem *ath79_reset_base;
+EXPORT_SYMBOL_GPL(ath79_reset_base);
+static void __iomem *ath79_ddr_base;
+static void __iomem *ath79_ddr_wb_flush_base;
+static void __iomem *ath79_ddr_pci_win_base;
+
+void ath79_ddr_ctrl_init(void)
+{
+	ath79_ddr_base = ioremap(AR71XX_DDR_CTRL_BASE,
+					 AR71XX_DDR_CTRL_SIZE);
+	if (soc_is_ar913x() || soc_is_ar724x() || soc_is_ar933x()) {
+		ath79_ddr_wb_flush_base = ath79_ddr_base + 0x7c;
+		ath79_ddr_pci_win_base = 0;
+	} else {
+		ath79_ddr_wb_flush_base = ath79_ddr_base + 0x9c;
+		ath79_ddr_pci_win_base = ath79_ddr_base + 0x7c;
+	}
+}
+EXPORT_SYMBOL_GPL(ath79_ddr_ctrl_init);
+
+void ath79_ddr_wb_flush(u32 reg)
+{
+	void __iomem *flush_reg = ath79_ddr_wb_flush_base + (reg * 4);
+
+	/* Flush the DDR write buffer. */
+	__raw_writel(0x1, flush_reg);
+	while (__raw_readl(flush_reg) & 0x1)
+		;
+
+	/* It must be run twice. */
+	__raw_writel(0x1, flush_reg);
+	while (__raw_readl(flush_reg) & 0x1)
+		;
+}
+EXPORT_SYMBOL_GPL(ath79_ddr_wb_flush);
+
+void ath79_ddr_set_pci_windows(void)
+{
+	BUG_ON(!ath79_ddr_pci_win_base);
+
+	__raw_writel(AR71XX_PCI_WIN0_OFFS, ath79_ddr_pci_win_base + 0x0);
+	__raw_writel(AR71XX_PCI_WIN1_OFFS, ath79_ddr_pci_win_base + 0x4);
+	__raw_writel(AR71XX_PCI_WIN2_OFFS, ath79_ddr_pci_win_base + 0x8);
+	__raw_writel(AR71XX_PCI_WIN3_OFFS, ath79_ddr_pci_win_base + 0xc);
+	__raw_writel(AR71XX_PCI_WIN4_OFFS, ath79_ddr_pci_win_base + 0x10);
+	__raw_writel(AR71XX_PCI_WIN5_OFFS, ath79_ddr_pci_win_base + 0x14);
+	__raw_writel(AR71XX_PCI_WIN6_OFFS, ath79_ddr_pci_win_base + 0x18);
+	__raw_writel(AR71XX_PCI_WIN7_OFFS, ath79_ddr_pci_win_base + 0x1c);
+}
+EXPORT_SYMBOL_GPL(ath79_ddr_set_pci_windows);
+
+void ath79_device_reset_set(u32 mask)
+{
+	unsigned long flags;
+	u32 reg;
+	u32 t;
+
+	if (soc_is_ar71xx())
+		reg = AR71XX_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar724x())
+		reg = AR724X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar913x())
+		reg = AR913X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar933x())
+		reg = AR933X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar934x())
+		reg = AR934X_RESET_REG_RESET_MODULE;
+	else if (soc_is_qca953x())
+		reg = QCA953X_RESET_REG_RESET_MODULE;
+	else if (soc_is_qca955x())
+		reg = QCA955X_RESET_REG_RESET_MODULE;
+	else if (soc_is_qca956x() || soc_is_tp9343())
+		reg = QCA956X_RESET_REG_RESET_MODULE;
+	else
+		BUG();
+
+	spin_lock_irqsave(&ath79_device_reset_lock, flags);
+	t = ath79_reset_rr(reg);
+	ath79_reset_wr(reg, t | mask);
+	spin_unlock_irqrestore(&ath79_device_reset_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ath79_device_reset_set);
+
+void ath79_device_reset_clear(u32 mask)
+{
+	unsigned long flags;
+	u32 reg;
+	u32 t;
+
+	if (soc_is_ar71xx())
+		reg = AR71XX_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar724x())
+		reg = AR724X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar913x())
+		reg = AR913X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar933x())
+		reg = AR933X_RESET_REG_RESET_MODULE;
+	else if (soc_is_ar934x())
+		reg = AR934X_RESET_REG_RESET_MODULE;
+	else if (soc_is_qca953x())
+		reg = QCA953X_RESET_REG_RESET_MODULE;
+	else if (soc_is_qca955x())
+		reg = QCA955X_RESET_REG_RESET_MODULE;
+	else if (soc_is_qca956x() || soc_is_tp9343())
+		reg = QCA956X_RESET_REG_RESET_MODULE;
+	else
+		BUG();
+
+	spin_lock_irqsave(&ath79_device_reset_lock, flags);
+	t = ath79_reset_rr(reg);
+	ath79_reset_wr(reg, t & ~mask);
+	spin_unlock_irqrestore(&ath79_device_reset_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ath79_device_reset_clear);