From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/dca/Kconfig | 8 + drivers/dca/Makefile | 3 + drivers/dca/dca-core.c | 456 ++++++++++++++++++++++++++++++++++++++++++++++++ drivers/dca/dca-sysfs.c | 94 ++++++++++ 4 files changed, 561 insertions(+) create mode 100644 drivers/dca/Kconfig create mode 100644 drivers/dca/Makefile create mode 100644 drivers/dca/dca-core.c create mode 100644 drivers/dca/dca-sysfs.c (limited to 'drivers/dca') diff --git a/drivers/dca/Kconfig b/drivers/dca/Kconfig new file mode 100644 index 000000000..fd3348131 --- /dev/null +++ b/drivers/dca/Kconfig @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# DCA server configuration +# + +config DCA + tristate + diff --git a/drivers/dca/Makefile b/drivers/dca/Makefile new file mode 100644 index 000000000..f3f0f02c7 --- /dev/null +++ b/drivers/dca/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_DCA) += dca.o +dca-objs := dca-core.o dca-sysfs.o diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c new file mode 100644 index 000000000..583510850 --- /dev/null +++ b/drivers/dca/dca-core.c @@ -0,0 +1,456 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved. + */ + +/* + * This driver supports an interface for DCA clients and providers to meet. + */ + +#include +#include +#include +#include +#include +#include + +#define DCA_VERSION "1.12.1" + +MODULE_VERSION(DCA_VERSION); +MODULE_DESCRIPTION("Intel Direct Cache Access (DCA) service module"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Intel Corporation"); + +static DEFINE_RAW_SPINLOCK(dca_lock); + +static LIST_HEAD(dca_domains); + +static BLOCKING_NOTIFIER_HEAD(dca_provider_chain); + +static int dca_providers_blocked; + +static struct pci_bus *dca_pci_rc_from_dev(struct device *dev) +{ + struct pci_dev *pdev = to_pci_dev(dev); + struct pci_bus *bus = pdev->bus; + + while (bus->parent) + bus = bus->parent; + + return bus; +} + +static struct dca_domain *dca_allocate_domain(struct pci_bus *rc) +{ + struct dca_domain *domain; + + domain = kzalloc_obj(*domain, GFP_NOWAIT); + if (!domain) + return NULL; + + INIT_LIST_HEAD(&domain->dca_providers); + domain->pci_rc = rc; + + return domain; +} + +static void dca_free_domain(struct dca_domain *domain) +{ + list_del(&domain->node); + kfree(domain); +} + +static int dca_provider_ioat_ver_3_0(struct device *dev) +{ + struct pci_dev *pdev = to_pci_dev(dev); + + return ((pdev->vendor == PCI_VENDOR_ID_INTEL) && + ((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) || + (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7))); +} + +static void unregister_dca_providers(void) +{ + struct dca_provider *dca, *_dca; + struct list_head unregistered_providers; + struct dca_domain *domain; + unsigned long flags; + + blocking_notifier_call_chain(&dca_provider_chain, + DCA_PROVIDER_REMOVE, NULL); + + INIT_LIST_HEAD(&unregistered_providers); + + raw_spin_lock_irqsave(&dca_lock, flags); + + if (list_empty(&dca_domains)) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return; + } + + /* at this point only one domain in the list is expected */ + domain = list_first_entry(&dca_domains, struct dca_domain, node); + + list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node) + list_move(&dca->node, &unregistered_providers); + + dca_free_domain(domain); + + raw_spin_unlock_irqrestore(&dca_lock, flags); + + list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) { + dca_sysfs_remove_provider(dca); + list_del(&dca->node); + } +} + +static struct dca_domain *dca_find_domain(struct pci_bus *rc) +{ + struct dca_domain *domain; + + list_for_each_entry(domain, &dca_domains, node) + if (domain->pci_rc == rc) + return domain; + + return NULL; +} + +static struct dca_domain *dca_get_domain(struct device *dev) +{ + struct pci_bus *rc; + struct dca_domain *domain; + + rc = dca_pci_rc_from_dev(dev); + domain = dca_find_domain(rc); + + if (!domain) { + if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) + dca_providers_blocked = 1; + } + + return domain; +} + +static struct dca_provider *dca_find_provider_by_dev(struct device *dev) +{ + struct dca_provider *dca; + struct pci_bus *rc; + struct dca_domain *domain; + + if (dev) { + rc = dca_pci_rc_from_dev(dev); + domain = dca_find_domain(rc); + if (!domain) + return NULL; + } else { + if (!list_empty(&dca_domains)) + domain = list_first_entry(&dca_domains, + struct dca_domain, + node); + else + return NULL; + } + + list_for_each_entry(dca, &domain->dca_providers, node) + if ((!dev) || (dca->ops->dev_managed(dca, dev))) + return dca; + + return NULL; +} + +/** + * dca_add_requester - add a dca client to the list + * @dev - the device that wants dca service + */ +int dca_add_requester(struct device *dev) +{ + struct dca_provider *dca; + int err, slot = -ENODEV; + unsigned long flags; + struct pci_bus *pci_rc; + struct dca_domain *domain; + + if (!dev) + return -EFAULT; + + raw_spin_lock_irqsave(&dca_lock, flags); + + /* check if the requester has not been added already */ + dca = dca_find_provider_by_dev(dev); + if (dca) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return -EEXIST; + } + + pci_rc = dca_pci_rc_from_dev(dev); + domain = dca_find_domain(pci_rc); + if (!domain) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return -ENODEV; + } + + list_for_each_entry(dca, &domain->dca_providers, node) { + slot = dca->ops->add_requester(dca, dev); + if (slot >= 0) + break; + } + + raw_spin_unlock_irqrestore(&dca_lock, flags); + + if (slot < 0) + return slot; + + err = dca_sysfs_add_req(dca, dev, slot); + if (err) { + raw_spin_lock_irqsave(&dca_lock, flags); + if (dca == dca_find_provider_by_dev(dev)) + dca->ops->remove_requester(dca, dev); + raw_spin_unlock_irqrestore(&dca_lock, flags); + return err; + } + + return 0; +} +EXPORT_SYMBOL_GPL(dca_add_requester); + +/** + * dca_remove_requester - remove a dca client from the list + * @dev - the device that wants dca service + */ +int dca_remove_requester(struct device *dev) +{ + struct dca_provider *dca; + int slot; + unsigned long flags; + + if (!dev) + return -EFAULT; + + raw_spin_lock_irqsave(&dca_lock, flags); + dca = dca_find_provider_by_dev(dev); + if (!dca) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return -ENODEV; + } + slot = dca->ops->remove_requester(dca, dev); + raw_spin_unlock_irqrestore(&dca_lock, flags); + + if (slot < 0) + return slot; + + dca_sysfs_remove_req(dca, slot); + + return 0; +} +EXPORT_SYMBOL_GPL(dca_remove_requester); + +/** + * dca_common_get_tag - return the dca tag (serves both new and old api) + * @dev - the device that wants dca service + * @cpu - the cpuid as returned by get_cpu() + */ +static u8 dca_common_get_tag(struct device *dev, int cpu) +{ + struct dca_provider *dca; + u8 tag; + unsigned long flags; + + raw_spin_lock_irqsave(&dca_lock, flags); + + dca = dca_find_provider_by_dev(dev); + if (!dca) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return -ENODEV; + } + tag = dca->ops->get_tag(dca, dev, cpu); + + raw_spin_unlock_irqrestore(&dca_lock, flags); + return tag; +} + +/** + * dca3_get_tag - return the dca tag to the requester device + * for the given cpu (new api) + * @dev - the device that wants dca service + * @cpu - the cpuid as returned by get_cpu() + */ +u8 dca3_get_tag(struct device *dev, int cpu) +{ + if (!dev) + return -EFAULT; + + return dca_common_get_tag(dev, cpu); +} +EXPORT_SYMBOL_GPL(dca3_get_tag); + +/** + * dca_get_tag - return the dca tag for the given cpu (old api) + * @cpu - the cpuid as returned by get_cpu() + */ +u8 dca_get_tag(int cpu) +{ + return dca_common_get_tag(NULL, cpu); +} +EXPORT_SYMBOL_GPL(dca_get_tag); + +/** + * alloc_dca_provider - get data struct for describing a dca provider + * @ops - pointer to struct of dca operation function pointers + * @priv_size - size of extra mem to be added for provider's needs + */ +struct dca_provider *alloc_dca_provider(const struct dca_ops *ops, + int priv_size) +{ + struct dca_provider *dca; + int alloc_size; + + alloc_size = (sizeof(*dca) + priv_size); + dca = kzalloc(alloc_size, GFP_KERNEL); + if (!dca) + return NULL; + dca->ops = ops; + + return dca; +} +EXPORT_SYMBOL_GPL(alloc_dca_provider); + +/** + * free_dca_provider - release the dca provider data struct + * @ops - pointer to struct of dca operation function pointers + * @priv_size - size of extra mem to be added for provider's needs + */ +void free_dca_provider(struct dca_provider *dca) +{ + kfree(dca); +} +EXPORT_SYMBOL_GPL(free_dca_provider); + +/** + * register_dca_provider - register a dca provider + * @dca - struct created by alloc_dca_provider() + * @dev - device providing dca services + */ +int register_dca_provider(struct dca_provider *dca, struct device *dev) +{ + int err; + unsigned long flags; + struct dca_domain *domain, *newdomain = NULL; + + raw_spin_lock_irqsave(&dca_lock, flags); + if (dca_providers_blocked) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return -ENODEV; + } + raw_spin_unlock_irqrestore(&dca_lock, flags); + + err = dca_sysfs_add_provider(dca, dev); + if (err) + return err; + + raw_spin_lock_irqsave(&dca_lock, flags); + domain = dca_get_domain(dev); + if (!domain) { + struct pci_bus *rc; + + if (dca_providers_blocked) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + dca_sysfs_remove_provider(dca); + unregister_dca_providers(); + return -ENODEV; + } + + raw_spin_unlock_irqrestore(&dca_lock, flags); + rc = dca_pci_rc_from_dev(dev); + newdomain = dca_allocate_domain(rc); + if (!newdomain) + return -ENODEV; + raw_spin_lock_irqsave(&dca_lock, flags); + /* Recheck, we might have raced after dropping the lock */ + domain = dca_get_domain(dev); + if (!domain) { + domain = newdomain; + newdomain = NULL; + list_add(&domain->node, &dca_domains); + } + } + list_add(&dca->node, &domain->dca_providers); + raw_spin_unlock_irqrestore(&dca_lock, flags); + + blocking_notifier_call_chain(&dca_provider_chain, + DCA_PROVIDER_ADD, NULL); + kfree(newdomain); + return 0; +} +EXPORT_SYMBOL_GPL(register_dca_provider); + +/** + * unregister_dca_provider - remove a dca provider + * @dca - struct created by alloc_dca_provider() + */ +void unregister_dca_provider(struct dca_provider *dca, struct device *dev) +{ + unsigned long flags; + struct pci_bus *pci_rc; + struct dca_domain *domain; + + blocking_notifier_call_chain(&dca_provider_chain, + DCA_PROVIDER_REMOVE, NULL); + + raw_spin_lock_irqsave(&dca_lock, flags); + + if (list_empty(&dca_domains)) { + raw_spin_unlock_irqrestore(&dca_lock, flags); + return; + } + + list_del(&dca->node); + + pci_rc = dca_pci_rc_from_dev(dev); + domain = dca_find_domain(pci_rc); + if (list_empty(&domain->dca_providers)) + dca_free_domain(domain); + + raw_spin_unlock_irqrestore(&dca_lock, flags); + + dca_sysfs_remove_provider(dca); +} +EXPORT_SYMBOL_GPL(unregister_dca_provider); + +/** + * dca_register_notify - register a client's notifier callback + */ +void dca_register_notify(struct notifier_block *nb) +{ + blocking_notifier_chain_register(&dca_provider_chain, nb); +} +EXPORT_SYMBOL_GPL(dca_register_notify); + +/** + * dca_unregister_notify - remove a client's notifier callback + */ +void dca_unregister_notify(struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&dca_provider_chain, nb); +} +EXPORT_SYMBOL_GPL(dca_unregister_notify); + +static int __init dca_init(void) +{ + pr_info("dca service started, version %s\n", DCA_VERSION); + return dca_sysfs_init(); +} + +static void __exit dca_exit(void) +{ + dca_sysfs_exit(); +} + +arch_initcall(dca_init); +module_exit(dca_exit); + diff --git a/drivers/dca/dca-sysfs.c b/drivers/dca/dca-sysfs.c new file mode 100644 index 000000000..b915c2b46 --- /dev/null +++ b/drivers/dca/dca-sysfs.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static const struct class dca_class = { + .name = "dca", +}; +static struct idr dca_idr; +static spinlock_t dca_idr_lock; + +int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot) +{ + struct device *cd; + static int req_count; + + cd = device_create(&dca_class, dca->cd, MKDEV(0, slot + 1), NULL, + "requester%d", req_count++); + return PTR_ERR_OR_ZERO(cd); +} + +void dca_sysfs_remove_req(struct dca_provider *dca, int slot) +{ + device_destroy(&dca_class, MKDEV(0, slot + 1)); +} + +int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev) +{ + struct device *cd; + int ret; + + idr_preload(GFP_KERNEL); + spin_lock(&dca_idr_lock); + + ret = idr_alloc(&dca_idr, dca, 0, 0, GFP_NOWAIT); + if (ret >= 0) + dca->id = ret; + + spin_unlock(&dca_idr_lock); + idr_preload_end(); + if (ret < 0) + return ret; + + cd = device_create(&dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id); + if (IS_ERR(cd)) { + spin_lock(&dca_idr_lock); + idr_remove(&dca_idr, dca->id); + spin_unlock(&dca_idr_lock); + return PTR_ERR(cd); + } + dca->cd = cd; + return 0; +} + +void dca_sysfs_remove_provider(struct dca_provider *dca) +{ + device_unregister(dca->cd); + dca->cd = NULL; + spin_lock(&dca_idr_lock); + idr_remove(&dca_idr, dca->id); + spin_unlock(&dca_idr_lock); +} + +int __init dca_sysfs_init(void) +{ + int err; + + idr_init(&dca_idr); + spin_lock_init(&dca_idr_lock); + + err = class_register(&dca_class); + if (err) { + idr_destroy(&dca_idr); + return err; + } + return 0; +} + +void __exit dca_sysfs_exit(void) +{ + class_unregister(&dca_class); + idr_destroy(&dca_idr); +} + -- cgit v1.3.1