From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- drivers/soc/fujitsu/Kconfig | 16 +++++ drivers/soc/fujitsu/Makefile | 3 + drivers/soc/fujitsu/a64fx-diag.c | 151 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 170 insertions(+) create mode 100644 drivers/soc/fujitsu/Kconfig create mode 100644 drivers/soc/fujitsu/Makefile create mode 100644 drivers/soc/fujitsu/a64fx-diag.c (limited to 'drivers/soc/fujitsu') diff --git a/drivers/soc/fujitsu/Kconfig b/drivers/soc/fujitsu/Kconfig new file mode 100644 index 000000000..987731e80 --- /dev/null +++ b/drivers/soc/fujitsu/Kconfig @@ -0,0 +1,16 @@ +# SPDX-License-Identifier: GPL-2.0-only +menu "fujitsu SoC drivers" + +config A64FX_DIAG + bool "A64FX diag driver" + depends on ARM64 + depends on ACPI + help + Say Y here if you want to enable diag interrupt on Fujitsu A64FX. + This driver enables BMC's diagnostic requests and enables + A64FX-specific interrupts. This allows administrators to obtain + kernel dumps via diagnostic requests using ipmitool, etc. + + If unsure, say N. + +endmenu diff --git a/drivers/soc/fujitsu/Makefile b/drivers/soc/fujitsu/Makefile new file mode 100644 index 000000000..945bc1c14 --- /dev/null +++ b/drivers/soc/fujitsu/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_A64FX_DIAG) += a64fx-diag.o diff --git a/drivers/soc/fujitsu/a64fx-diag.c b/drivers/soc/fujitsu/a64fx-diag.c new file mode 100644 index 000000000..76cb0b6a2 --- /dev/null +++ b/drivers/soc/fujitsu/a64fx-diag.c @@ -0,0 +1,151 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * A64FX diag driver. + * Copyright (c) 2022 Fujitsu Ltd. + */ + +#include +#include +#include +#include +#include + +#define A64FX_DIAG_IRQ 1 +#define BMC_DIAG_INTERRUPT_ENABLE 0x40 +#define BMC_DIAG_INTERRUPT_STATUS 0x44 +#define BMC_DIAG_INTERRUPT_MASK BIT(31) + +struct a64fx_diag_priv { + void __iomem *mmsc_reg_base; + int irq; + bool has_nmi; +}; + +static irqreturn_t a64fx_diag_handler_nmi(int irq, void *dev_id) +{ + nmi_panic(NULL, "a64fx_diag: interrupt received\n"); + + return IRQ_HANDLED; +} + +static irqreturn_t a64fx_diag_handler_irq(int irq, void *dev_id) +{ + panic("a64fx_diag: interrupt received\n"); + + return IRQ_HANDLED; +} + +static void a64fx_diag_interrupt_clear(struct a64fx_diag_priv *priv) +{ + void __iomem *diag_status_reg_addr; + u32 mmsc; + + diag_status_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_STATUS; + mmsc = readl(diag_status_reg_addr); + if (mmsc & BMC_DIAG_INTERRUPT_MASK) + writel(BMC_DIAG_INTERRUPT_MASK, diag_status_reg_addr); +} + +static void a64fx_diag_interrupt_enable(struct a64fx_diag_priv *priv) +{ + void __iomem *diag_enable_reg_addr; + u32 mmsc; + + diag_enable_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_ENABLE; + mmsc = readl(diag_enable_reg_addr); + if (!(mmsc & BMC_DIAG_INTERRUPT_MASK)) { + mmsc |= BMC_DIAG_INTERRUPT_MASK; + writel(mmsc, diag_enable_reg_addr); + } +} + +static void a64fx_diag_interrupt_disable(struct a64fx_diag_priv *priv) +{ + void __iomem *diag_enable_reg_addr; + u32 mmsc; + + diag_enable_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_ENABLE; + mmsc = readl(diag_enable_reg_addr); + if (mmsc & BMC_DIAG_INTERRUPT_MASK) { + mmsc &= ~BMC_DIAG_INTERRUPT_MASK; + writel(mmsc, diag_enable_reg_addr); + } +} + +static int a64fx_diag_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct a64fx_diag_priv *priv; + unsigned long irq_flags; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (priv == NULL) + return -ENOMEM; + + priv->mmsc_reg_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->mmsc_reg_base)) + return PTR_ERR(priv->mmsc_reg_base); + + priv->irq = platform_get_irq(pdev, A64FX_DIAG_IRQ); + if (priv->irq < 0) + return priv->irq; + + platform_set_drvdata(pdev, priv); + + irq_flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_AUTOEN | + IRQF_NO_THREAD; + ret = request_nmi(priv->irq, &a64fx_diag_handler_nmi, irq_flags, + "a64fx_diag_nmi", NULL); + if (ret) { + ret = request_irq(priv->irq, &a64fx_diag_handler_irq, + irq_flags, "a64fx_diag_irq", NULL); + if (ret) { + dev_err(dev, "cannot register IRQ %d\n", ret); + return ret; + } + enable_irq(priv->irq); + } else { + enable_nmi(priv->irq); + priv->has_nmi = true; + } + + a64fx_diag_interrupt_clear(priv); + a64fx_diag_interrupt_enable(priv); + + return 0; +} + +static void a64fx_diag_remove(struct platform_device *pdev) +{ + struct a64fx_diag_priv *priv = platform_get_drvdata(pdev); + + a64fx_diag_interrupt_disable(priv); + a64fx_diag_interrupt_clear(priv); + + if (priv->has_nmi) + free_nmi(priv->irq, NULL); + else + free_irq(priv->irq, NULL); +} + +static const struct acpi_device_id a64fx_diag_acpi_match[] = { + { "FUJI2007", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, a64fx_diag_acpi_match); + + +static struct platform_driver a64fx_diag_driver = { + .driver = { + .name = "a64fx_diag_driver", + .acpi_match_table = ACPI_PTR(a64fx_diag_acpi_match), + }, + .probe = a64fx_diag_probe, + .remove = a64fx_diag_remove, +}; + +module_platform_driver(a64fx_diag_driver); + +MODULE_AUTHOR("Hitomi Hasegawa "); +MODULE_DESCRIPTION("A64FX diag driver"); -- cgit v1.3.1