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/cdx/cdx_msi.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 drivers/cdx/cdx_msi.c (limited to 'drivers/cdx/cdx_msi.c') diff --git a/drivers/cdx/cdx_msi.c b/drivers/cdx/cdx_msi.c new file mode 100644 index 000000000..c8d832b0b --- /dev/null +++ b/drivers/cdx/cdx_msi.c @@ -0,0 +1,193 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * AMD CDX bus driver MSI support + * + * Copyright (C) 2022-2023, Advanced Micro Devices, Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "cdx.h" + +static void cdx_msi_write_msg(struct irq_data *irq_data, struct msi_msg *msg) +{ + struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data); + struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev); + + /* We would not operate on msg here rather we wait for irq_bus_sync_unlock() + * to be called from preemptible task context. + */ + msi_desc->msg = *msg; + cdx_dev->msi_write_pending = true; +} + +static void cdx_msi_write_irq_lock(struct irq_data *irq_data) +{ + struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data); + struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev); + + mutex_lock(&cdx_dev->irqchip_lock); +} + +static void cdx_msi_write_irq_unlock(struct irq_data *irq_data) +{ + struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data); + struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev); + struct cdx_controller *cdx = cdx_dev->cdx; + struct cdx_device_config dev_config; + + if (!cdx_dev->msi_write_pending) { + mutex_unlock(&cdx_dev->irqchip_lock); + return; + } + + cdx_dev->msi_write_pending = false; + mutex_unlock(&cdx_dev->irqchip_lock); + + dev_config.msi.msi_index = msi_desc->msi_index; + dev_config.msi.data = msi_desc->msg.data; + dev_config.msi.addr = ((u64)(msi_desc->msg.address_hi) << 32) | msi_desc->msg.address_lo; + + /* + * dev_configure() is a controller callback which can interact with + * Firmware or other entities, and can sleep, so invoke this function + * outside of the mutex held region. + */ + dev_config.type = CDX_DEV_MSI_CONF; + if (cdx->ops->dev_configure) + cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, &dev_config); +} + +int cdx_enable_msi(struct cdx_device *cdx_dev) +{ + struct cdx_controller *cdx = cdx_dev->cdx; + struct cdx_device_config dev_config; + + dev_config.type = CDX_DEV_MSI_ENABLE; + dev_config.msi_enable = true; + if (cdx->ops->dev_configure) { + return cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, + &dev_config); + } + + return -EOPNOTSUPP; +} +EXPORT_SYMBOL_GPL(cdx_enable_msi); + +void cdx_disable_msi(struct cdx_device *cdx_dev) +{ + struct cdx_controller *cdx = cdx_dev->cdx; + struct cdx_device_config dev_config; + + dev_config.type = CDX_DEV_MSI_ENABLE; + dev_config.msi_enable = false; + if (cdx->ops->dev_configure) + cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, &dev_config); +} +EXPORT_SYMBOL_GPL(cdx_disable_msi); + +static struct irq_chip cdx_msi_irq_chip = { + .name = "CDX-MSI", + .irq_mask = irq_chip_mask_parent, + .irq_unmask = irq_chip_unmask_parent, + .irq_eoi = irq_chip_eoi_parent, + .irq_set_affinity = msi_domain_set_affinity, + .irq_write_msi_msg = cdx_msi_write_msg, + .irq_bus_lock = cdx_msi_write_irq_lock, + .irq_bus_sync_unlock = cdx_msi_write_irq_unlock +}; + +/* Convert an msi_desc to a unique identifier within the domain. */ +static irq_hw_number_t cdx_domain_calc_hwirq(struct cdx_device *dev, + struct msi_desc *desc) +{ + return ((irq_hw_number_t)dev->msi_dev_id << 10) | desc->msi_index; +} + +static void cdx_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc) +{ + arg->desc = desc; + arg->hwirq = cdx_domain_calc_hwirq(to_cdx_device(desc->dev), desc); +} + +static int cdx_msi_prepare(struct irq_domain *msi_domain, + struct device *dev, + int nvec, msi_alloc_info_t *info) +{ + struct of_phandle_args msi_spec = {}; + struct cdx_device *cdx_dev = to_cdx_device(dev); + struct device *parent = cdx_dev->cdx->dev; + struct msi_domain_info *msi_info; + int ret; + + /* Retrieve device ID from requestor ID using parent device */ + ret = of_map_msi_id(parent->of_node, cdx_dev->msi_dev_id, NULL, &msi_spec); + if (ret) { + dev_err(dev, "of_map_msi_id failed for MSI: %d\n", ret); + return ret; + } + of_node_put(msi_spec.np); + +#ifdef GENERIC_MSI_DOMAIN_OPS + /* Set the device Id to be passed to the GIC-ITS */ + info->scratchpad[0].ul = msi_spec.args[0]; +#endif + + msi_info = msi_get_domain_info(msi_domain->parent); + + return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info); +} + +static struct msi_domain_ops cdx_msi_ops = { + .msi_prepare = cdx_msi_prepare, + .set_desc = cdx_msi_set_desc +}; + +static struct msi_domain_info cdx_msi_domain_info = { + .ops = &cdx_msi_ops, + .chip = &cdx_msi_irq_chip, + .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | + MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS +}; + +struct irq_domain *cdx_msi_domain_init(struct device *dev) +{ + struct device_node *np = dev->of_node; + struct fwnode_handle *fwnode_handle; + struct irq_domain *cdx_msi_domain; + struct device_node *parent_node; + struct irq_domain *parent; + + fwnode_handle = of_fwnode_handle(np); + + parent_node = of_parse_phandle(np, "msi-map", 1); + if (!parent_node) { + dev_err(dev, "msi-map not present on cdx controller\n"); + return NULL; + } + + parent = irq_find_matching_fwnode(of_fwnode_handle(parent_node), DOMAIN_BUS_NEXUS); + of_node_put(parent_node); + if (!parent || !msi_get_domain_info(parent)) { + dev_err(dev, "unable to locate ITS domain\n"); + return NULL; + } + + cdx_msi_domain = msi_create_irq_domain(fwnode_handle, &cdx_msi_domain_info, parent); + if (!cdx_msi_domain) { + dev_err(dev, "unable to create CDX-MSI domain\n"); + return NULL; + } + + dev_dbg(dev, "CDX-MSI domain created\n"); + + return cdx_msi_domain; +} +EXPORT_SYMBOL_NS_GPL(cdx_msi_domain_init, "CDX_BUS_CONTROLLER"); 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