kernel/linux.git/drivers/acpi/nfit, branch v6.2.2

ACPI: NFIT: fix a potential deadlock during NFIT teardown

2023-01-25T20:55:33+00:00

Lockdep reports that acpi_nfit_shutdown() may deadlock against an opportune acpi_nfit_scrub(). acpi_nfit_scrub () is run from inside a 'work' and therefore has already acquired workqueue-internal locks. It also acquiires acpi_desc->init_mutex. acpi_nfit_shutdown() first acquires init_mutex, and was subsequently attempting to cancel any pending workqueue items. This reversed locking order causes a potential deadlock: ====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc3 #116 Tainted: G O N ------------------------------------------------------ libndctl/1958 is trying to acquire lock: ffff888129b461c0 ((work_completion)(&(&acpi_desc->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x43/0x450 but task is already holding lock: ffff888129b460e8 (&acpi_desc->init_mutex){+.+.}-{3:3}, at: acpi_nfit_shutdown+0x87/0xd0 [nfit] which lock already depends on the new lock. ... Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&acpi_desc->init_mutex); lock((work_completion)(&(&acpi_desc->dwork)->work)); lock(&acpi_desc->init_mutex); lock((work_completion)(&(&acpi_desc->dwork)->work)); *** DEADLOCK *** Since the workqueue manipulation is protected by its own internal locking, the cancellation of pending work doesn't need to be done under acpi_desc->init_mutex. Move cancel_delayed_work_sync() outside the init_mutex to fix the deadlock. Any work that starts after acpi_nfit_shutdown() drops the lock will see ARS_CANCEL, and the cancel_delayed_work_sync() will safely flush it out. Reported-by: Dan Williams Signed-off-by: Vishal Verma Link: https://lore.kernel.org/r/20230112-acpi_nfit_lockdep-v1-1-660be4dd10be@intel.com Signed-off-by: Dan Williams

Merge tag 'cxl-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

2022-12-12T21:55:31+00:00

Pull cxl updates from Dan Williams: "Compute Express Link (CXL) updates for 6.2. While it may seem backwards, the CXL update this time around includes some focus on CXL 1.x enabling where the work to date had been with CXL 2.0 (VH topologies) in mind. First generation CXL can mostly be supported via BIOS, similar to DDR, however it became clear there are use cases for OS native CXL error handling and some CXL 3.0 endpoint features can be deployed on CXL 1.x hosts (Restricted CXL Host (RCH) topologies). So, this update brings RCH topologies into the Linux CXL device model. In support of the ongoing CXL 2.0+ enabling two new core kernel facilities are added. One is the ability for the kernel to flag collisions between userspace access to PCI configuration registers and kernel accesses. This is brought on by the PCIe Data-Object-Exchange (DOE) facility, a hardware mailbox over config-cycles. The other is a cpu_cache_invalidate_memregion() API that maps to wbinvd_on_all_cpus() on x86. To prevent abuse it is disabled in guest VMs and architectures that do not support it yet. The CXL paths that need it, dynamic memory region creation and security commands (erase / unlock), are disabled when it is not present. As for the CXL 2.0+ this cycle the subsystem gains support Persistent Memory Security commands, error handling in response to PCIe AER notifications, and support for the "XOR" host bridge interleave algorithm. Summary: - Add the cpu_cache_invalidate_memregion() API for cache flushing in response to physical memory reconfiguration, or memory-side data invalidation from operations like secure erase or memory-device unlock. - Add a facility for the kernel to warn about collisions between kernel and userspace access to PCI configuration registers - Add support for Restricted CXL Host (RCH) topologies (formerly CXL 1.1) - Add handling and reporting of CXL errors reported via the PCIe AER mechanism - Add support for CXL Persistent Memory Security commands - Add support for the "XOR" algorithm for CXL host bridge interleave - Rework / simplify CXL to NVDIMM interactions - Miscellaneous cleanups and fixes" * tag 'cxl-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (71 commits) cxl/region: Fix memdev reuse check cxl/pci: Remove endian confusion cxl/pci: Add some type-safety to the AER trace points cxl/security: Drop security command ioctl uapi cxl/mbox: Add variable output size validation for internal commands cxl/mbox: Enable cxl_mbox_send_cmd() users to validate output size cxl/security: Fix Get Security State output payload endian handling cxl: update names for interleave ways conversion macros cxl: update names for interleave granularity conversion macros cxl/acpi: Warn about an invalid CHBCR in an existing CHBS entry tools/testing/cxl: Require cache invalidation bypass cxl/acpi: Fail decoder add if CXIMS for HBIG is missing cxl/region: Fix spelling mistake "memergion" -> "memregion" cxl/regs: Fix sparse warning cxl/acpi: Set ACPI's CXL _OSC to indicate RCD mode support tools/testing/cxl: Add an RCH topology cxl/port: Add RCD endpoint port enumeration cxl/mem: Move devm_cxl_add_endpoint() from cxl_core to cxl_mem tools/testing/cxl: Add XOR Math support to cxl_test cxl/acpi: Support CXL XOR Interleave Math (CXIMS) ...

nvdimm/region: Move cache management to the region driver

2022-12-03T07:52:32+00:00

Now that cpu_cache_invalidate_memregion() is generically available, use it to centralize CPU cache management in the nvdimm region driver. This trades off removing redundant per-dimm CPU cache flushing with an opportunistic flush on every region disable event to cover the case of sensitive dirty data in the cache being written back to media after a secure erase / overwrite event. Reviewed-by: Davidlohr Bueso Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/166993221550.1995348.16843505129579060258.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

ACPI: make remove callback of ACPI driver void

2022-11-23T18:11:22+00:00

For bus-based driver, device removal is implemented as: 1 device_remove()-> 2 bus->remove()-> 3 driver->remove() Driver core needs no inform from callee(bus driver) about the result of remove callback. In that case, commit fc7a6209d571 ("bus: Make remove callback return void") forces bus_type::remove be void-returned. Now we have the situation that both 1 & 2 of calling chain are void-returned, so it does not make much sense for 3(driver->remove) to return non-void to its caller. So the basic idea behind this change is making remove() callback of any bus-based driver to be void-returned. This change, for itself, is for device drivers based on acpi-bus. Acked-by: Uwe Kleine-König Acked-by: Lee Jones Acked-by: Dmitry Torokhov Reviewed-by: Hans de Goede Signed-off-by: Dawei Li Reviewed-by: Maximilian Luz # for drivers/platform/surface/* Signed-off-by: Rafael J. Wysocki

memregion: Add cpu_cache_invalidate_memregion() interface

2022-11-14T18:07:22+00:00

With CXL security features, and CXL dynamic provisioning, global CPU cache flushing nvdimm requirements are no longer specific to that subsystem, even beyond the scope of security_ops. CXL will need such semantics for features not necessarily limited to persistent memory. The functionality this is enabling is to be able to instantaneously secure erase potentially terabytes of memory at once and the kernel needs to be sure that none of the data from before the erase is still present in the cache. It is also used when unlocking a memory device where speculative reads and firmware accesses could have cached poison from before the device was unlocked. Lastly this facility is used when mapping new devices, or new capacity into an established physical address range. I.e. when the driver switches DeviceA mapping AddressX to DeviceB mapping AddressX then any cached data from DeviceA:AddressX needs to be invalidated. This capability is typically only used once per-boot (for unlock), or once per bare metal provisioning event (secure erase), like when handing off the system to another tenant or decommissioning a device. It may also be used for dynamic CXL region provisioning. Users must first call cpu_cache_has_invalidate_memregion() to know whether this functionality is available on the architecture. On x86 this respects the constraints of when wbinvd() is tolerable. It is already the case that wbinvd() is problematic to allow in VMs due its global performance impact and KVM, for example, has been known to just trap and ignore the call. With confidential computing guest execution of wbinvd() may even trigger an exception. Given guests should not be messing with the bare metal address map via CXL configuration changes cpu_cache_has_invalidate_memregion() returns false in VMs. While this global cache invalidation facility, is exported to modules, since NVDIMM and CXL support can be built as a module, it is not for general use. The intent is that this facility is not available outside of specific "device-memory" use cases. To make that expectation as clear as possible the API is scoped to a new "DEVMEM" module namespace that only the NVDIMM and CXL subsystems are expected to import. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: Andy Lutomirski Cc: Peter Zijlstra Tested-by: Dave Jiang Signed-off-by: Davidlohr Bueso Acked-by: Dave Hansen Co-developed-by: Dan Williams Signed-off-by: Dan Williams

Merge tag 'cxl-for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

2022-05-28T04:24:19+00:00

Pull cxl updates from Dan Williams: "Compute Express Link (CXL) updates for this cycle. The highlight is new driver-core infrastructure and CXL subsystem changes for allowing lockdep to validate device_lock() usage. Thanks to PeterZ for setting me straight on the current capabilities of the lockdep API, and Greg acked it as well. On the CXL ACPI side this update adds support for CXL _OSC so that platform firmware knows that it is safe to still grant Linux native control of PCIe hotplug and error handling in the presence of CXL devices. A circular dependency problem was discovered between suspend and CXL memory for cases where the suspend image might be stored in CXL memory where that image also contains the PCI register state to restore to re-enable the device. Disable suspend for now until an architecture is defined to clarify that conflict. Lastly a collection of reworks, fixes, and cleanups to the CXL subsystem where support for snooping mailbox commands and properly handling the "mem_enable" flow are the highlights. Summary: - Add driver-core infrastructure for lockdep validation of device_lock(), and fixup a deadlock report that was previously hidden behind the 'lockdep no validate' policy. - Add CXL _OSC support for claiming native control of CXL hotplug and error handling. - Disable suspend in the presence of CXL memory unless and until a protocol is identified for restoring PCI device context from memory hosted on CXL PCI devices. - Add support for snooping CXL mailbox commands to protect against inopportune changes, like set-partition with the 'immediate' flag set. - Rework how the driver detects legacy CXL 1.1 configurations (CXL DVSEC / 'mem_enable') before enabling new CXL 2.0 decode configurations (CXL HDM Capability). - Miscellaneous cleanups and fixes from -next exposure" * tag 'cxl-for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (47 commits) cxl/port: Enable HDM Capability after validating DVSEC Ranges cxl/port: Reuse 'struct cxl_hdm' context for hdm init cxl/port: Move endpoint HDM Decoder Capability init to port driver cxl/pci: Drop @info argument to cxl_hdm_decode_init() cxl/mem: Merge cxl_dvsec_ranges() and cxl_hdm_decode_init() cxl/mem: Skip range enumeration if mem_enable clear cxl/mem: Consolidate CXL DVSEC Range enumeration in the core cxl/pci: Move cxl_await_media_ready() to the core cxl/mem: Validate port connectivity before dvsec ranges cxl/mem: Fix cxl_mem_probe() error exit cxl/pci: Drop wait_for_valid() from cxl_await_media_ready() cxl/pci: Consolidate wait_for_media() and wait_for_media_ready() cxl/mem: Drop mem_enabled check from wait_for_media() nvdimm: Fix firmware activation deadlock scenarios device-core: Kill the lockdep_mutex nvdimm: Drop nd_device_lock() ACPI: NFIT: Drop nfit_device_lock() nvdimm: Replace lockdep_mutex with local lock classes cxl: Drop cxl_device_lock() cxl/acpi: Add root device lockdep validation ...

acpi/nfit: rely on mce->misc to determine poison granularity

2022-05-16T18:46:44+00:00

nfit_handle_mec() hardcode poison granularity at L1_CACHE_BYTES. Instead, let the driver rely on mce->misc register to determine the poison granularity. Suggested-by: Dan Williams Reviewed-by: Dan Williams Signed-off-by: Jane Chu Link: https://lore.kernel.org/r/20220422224508.440670-2-jane.chu@oracle.com Signed-off-by: Dan Williams

ACPI: NFIT: Drop nfit_device_lock()

2022-04-28T21:01:55+00:00

The nfit_device_lock() helper was added to provide lockdep coverage for the NFIT driver's usage of device_lock() on the nvdimm_bus object. Now that nvdimm_bus objects have their own lock class this wrapper can be dropped. Cc: Vishal Verma Cc: Dave Jiang Cc: Ira Weiny Reviewed-by: Ira Weiny Link: https://lore.kernel.org/r/165055521409.3745911.8085645201146909612.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams

nvdimm/region: Delete nd_blk_region infrastructure

2022-03-11T23:53:13+00:00

Now that the nd_namespace_blk infrastructure is removed, delete all the region machinery to coordinate provisioning aliased capacity between PMEM and BLK. Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/164688418803.2879318.1302315202397235855.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams

ACPI: NFIT: Remove block aperture support

2022-03-11T23:53:13+00:00

Delete the code to parse interleave-descriptor-tables and coordinate I/O through a BLK aperture. Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/164688418240.2879318.400185926874596938.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams