user/sven/linux.git/kernel/resource.c, branch v6.7.9

kernel/resource: Increment by align value in get_free_mem_region()

2023-12-05T01:19:03Z

Currently get_free_mem_region() searches for available capacity in increments equal to the region size being requested. This can cause the search to take giant steps through the resource leaving needless gaps and missing available space. Specifically 'cxl create-region' fails with ERANGE even though capacity of the given size and CXL's expected 256M x InterleaveWays alignment can be satisfied. Replace the total-request-size increment with a next alignment increment so that the next possible address is always examined for availability. Fixes: 14b80582c43e ("resource: Introduce alloc_free_mem_region()") Reported-by: Dmytro Adamenko Reported-by: Dan Williams Signed-off-by: Alison Schofield Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/20231113221324.1118092-1-alison.schofield@intel.com Cc: Jason Gunthorpe Reviewed-by: Christoph Hellwig Signed-off-by: Dan Williams

resource: Unify next_resource() and next_resource_skip_children()

2023-10-05T11:58:07Z

We have the next_resource() is used once and no user for the next_resource_skip_children() outside of the for_each_resource(). Unify them by adding skip_children parameter to the next_resource(). Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20230912165312.402422-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

resource: Reuse for_each_resource() macro

2023-10-05T11:58:07Z

We have a few places where for_each_resource() is open coded. Replace that by the macro. This makes code easier to read and understand. With this, compile r_next() only for CONFIG_PROC_FS=y. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20230912165312.402422-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

dax/kmem: Fix leak of memory-hotplug resources

2023-02-17T22:58:01Z

While experimenting with CXL region removal the following corruption of /proc/iomem appeared. Before: f010000000-f04fffffff : CXL Window 0 f010000000-f02fffffff : region4 f010000000-f02fffffff : dax4.0 f010000000-f02fffffff : System RAM (kmem) After (modprobe -r cxl_test): f010000000-f02fffffff : **redacted binary garbage** f010000000-f02fffffff : System RAM (kmem) ...and testing further the same is visible with persistent memory assigned to kmem: Before: 480000000-243fffffff : Persistent Memory 480000000-57e1fffff : namespace3.0 580000000-243fffffff : dax3.0 580000000-243fffffff : System RAM (kmem) After (ndctl disable-region all): 480000000-243fffffff : Persistent Memory 580000000-243fffffff : ***redacted binary garbage*** 580000000-243fffffff : System RAM (kmem) The corrupted data is from a use-after-free of the "dax4.0" and "dax3.0" resources, and it also shows that the "System RAM (kmem)" resource is not being removed. The bug does not appear after "modprobe -r kmem", it requires the parent of "dax4.0" and "dax3.0" to be removed which re-parents the leaked "System RAM (kmem)" instances. Those in turn reference the freed resource as a parent. First up for the fix is release_mem_region_adjustable() needs to reliably delete the resource inserted by add_memory_driver_managed(). That is thwarted by a check for IORESOURCE_SYSRAM that predates the dax/kmem driver, from commit: 65c78784135f ("kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable") That appears to be working around the behavior of HMM's "MEMORY_DEVICE_PUBLIC" facility that has since been deleted. With that check removed the "System RAM (kmem)" resource gets removed, but corruption still occurs occasionally because the "dax" resource is not reliably removed. The dax range information is freed before the device is unregistered, so the driver can not reliably recall (another use after free) what it is meant to release. Lastly if that use after free got lucky, the driver was covering up the leak of "System RAM (kmem)" due to its use of release_resource() which detaches, but does not free, child resources. The switch to remove_resource() forces remove_memory() to be responsible for the deletion of the resource added by add_memory_driver_managed(). Fixes: c2f3011ee697 ("device-dax: add an allocation interface for device-dax instances") Cc: Cc: Oscar Salvador Cc: David Hildenbrand Cc: Pavel Tatashin Reviewed-by: Vishal Verma Reviewed-by: Pasha Tatashin Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/167653656244.3147810.5705900882794040229.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-12-16T11:54:54Z

Pull driver core updates from Greg KH: "Here is the set of driver core and kernfs changes for 6.2-rc1. The "big" change in here is the addition of a new macro, container_of_const() that will preserve the "const-ness" of a pointer passed into it. The "problem" of the current container_of() macro is that if you pass in a "const *", out of it can comes a non-const pointer unless you specifically ask for it. For many usages, we want to preserve the "const" attribute by using the same call. For a specific example, this series changes the kobj_to_dev() macro to use it, allowing it to be used no matter what the const value is. This prevents every subsystem from having to declare 2 different individual macros (i.e. kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce the const value at build time, which having 2 macros would not do either. The driver for all of this have been discussions with the Rust kernel developers as to how to properly mark driver core, and kobject, objects as being "non-mutable". The changes to the kobject and driver core in this pull request are the result of that, as there are lots of paths where kobjects and device pointers are not modified at all, so marking them as "const" allows the compiler to enforce this. So, a nice side affect of the Rust development effort has been already to clean up the driver core code to be more obvious about object rules. All of this has been bike-shedded in quite a lot of detail on lkml with different names and implementations resulting in the tiny version we have in here, much better than my original proposal. Lots of subsystem maintainers have acked the changes as well. Other than this change, included in here are smaller stuff like: - kernfs fixes and updates to handle lock contention better - vmlinux.lds.h fixes and updates - sysfs and debugfs documentation updates - device property updates All of these have been in the linux-next tree for quite a while with no problems" * tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits) device property: Fix documentation for fwnode_get_next_parent() firmware_loader: fix up to_fw_sysfs() to preserve const usb.h: take advantage of container_of_const() device.h: move kobj_to_dev() to use container_of_const() container_of: add container_of_const() that preserves const-ness of the pointer driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion. driver core: fix up missed scsi/cxlflash class.devnode() conversion. driver core: fix up some missing class.devnode() conversions. driver core: make struct class.devnode() take a const * driver core: make struct class.dev_uevent() take a const * cacheinfo: Remove of_node_put() for fw_token device property: Add a blank line in Kconfig of tests device property: Rename goto label to be more precise device property: Move PROPERTY_ENTRY_BOOL() a bit down device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*() kernfs: fix all kernel-doc warnings and multiple typos driver core: pass a const * into of_device_uevent() kobject: kset_uevent_ops: make name() callback take a const * kobject: kset_uevent_ops: make filter() callback take a const * kobject: make kobject_namespace take a const * ...

PCI: Allow drivers to request exclusive config regions

2022-11-14T18:07:22Z

PCI config space access from user space has traditionally been unrestricted with writes being an understood risk for device operation. Unfortunately, device breakage or odd behavior from config writes lacks indicators that can leave driver writers confused when evaluating failures. This is especially true with the new PCIe Data Object Exchange (DOE) mailbox protocol where backdoor shenanigans from user space through things such as vendor defined protocols may affect device operation without complete breakage. A prior proposal restricted read and writes completely.[1] Greg and Bjorn pointed out that proposal is flawed for a couple of reasons. First, lspci should always be allowed and should not interfere with any device operation. Second, setpci is a valuable tool that is sometimes necessary and it should not be completely restricted.[2] Finally methods exist for full lock of device access if required. Even though access should not be restricted it would be nice for driver writers to be able to flag critical parts of the config space such that interference from user space can be detected. Introduce pci_request_config_region_exclusive() to mark exclusive config regions. Such regions trigger a warning and kernel taint if accessed via user space. Create pci_warn_once() to restrict the user from spamming the log. [1] https://lore.kernel.org/all/161663543465.1867664.5674061943008380442.stgit@dwillia2-desk3.amr.corp.intel.com/ [2] https://lore.kernel.org/all/YF8NGeGv9vYcMfTV@kroah.com/ Cc: Bjorn Helgaas Cc: Greg Kroah-Hartman Reviewed-by: Jonathan Cameron Suggested-by: Dan Williams Signed-off-by: Ira Weiny Acked-by: Greg Kroah-Hartman Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20220926215711.2893286-2-ira.weiny@intel.com Signed-off-by: Dan Williams

resource: Replace printk(KERN_WARNING) by pr_warn(), printk() by pr_info()

2022-11-10T17:58:24Z

Replace printk(KERN_WARNING) by pr_warn() and printk() by pr_info(). While at it, use %pa for the resource_size_t variables. With that, for the sake of consistency, introduce a temporary variable for the end address in iomem_map_sanity_check() like it's done in another function in the same module. Signed-off-by: Andy Shevchenko Reviewed-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20221109155618.42276-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

resource: Introduce alloc_free_mem_region()

2022-07-22T00:19:25Z

The core of devm_request_free_mem_region() is a helper that searches for free space in iomem_resource and performs __request_region_locked() on the result of that search. The policy choices of the implementation conform to what CONFIG_DEVICE_PRIVATE users want which is memory that is immediately marked busy, and a preference to search for the first-fit free range in descending order from the top of the physical address space. CXL has a need for a similar allocator, but with the following tweaks: 1/ Search for free space in ascending order 2/ Search for free space relative to a given CXL window 3/ 'insert' rather than 'request' the new resource given downstream drivers from the CXL Region driver (like the pmem or dax drivers) are responsible for request_mem_region() when they activate the memory range. Rework __request_free_mem_region() into get_free_mem_region() which takes a set of GFR_* (Get Free Region) flags to control the allocation policy (ascending vs descending), and "busy" policy (insert_resource() vs request_region()). As part of the consolidation of the legacy GFR_REQUEST_REGION case with the new default of just inserting a new resource into the free space some minor cleanups like not checking for NULL before calling devres_free() (which does its own check) is included. Suggested-by: Jason Gunthorpe Link: https://lore.kernel.org/linux-cxl/20220420143406.GY2120790@nvidia.com/ Cc: Matthew Wilcox Cc: Christoph Hellwig Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/165784333333.1758207.13703329337805274043.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

cxl/acpi: Track CXL resources in iomem_resource

2022-07-21T15:40:01Z

Recall that CXL capable address ranges, on ACPI platforms, are published in the CEDT.CFMWS (CXL Early Discovery Table: CXL Fixed Memory Window Structures). These windows represent both the actively mapped capacity and the potential address space that can be dynamically assigned to a new CXL decode configuration (region / interleave-set). CXL endpoints like DDR DIMMs can be mapped at any physical address including 0 and legacy ranges. There is an expectation and requirement that the /proc/iomem interface and the iomem_resource tree in the kernel reflect the full set of platform address ranges. I.e. that every address range that platform firmware and bus drivers enumerate be reflected as an iomem_resource entry. The hard requirement to do this for CXL arises from the fact that facilities like CONFIG_DEVICE_PRIVATE expect to be able to treat empty iomem_resource ranges as free for software to use as proxy address space. Without CXL publishing its potential address ranges in iomem_resource, the CONFIG_DEVICE_PRIVATE mechanism may inadvertently steal capacity reserved for runtime provisioning of new CXL regions. So, iomem_resource needs to know about both active and potential CXL resource ranges. The active CXL resources might already be reflected in iomem_resource as "System RAM". insert_resource_expand_to_fit() handles re-parenting "System RAM" underneath a CXL window. The "_expand_to_fit()" behavior handles cases where a CXL window is not a strict superset of an existing entry in the iomem_resource tree. The "_expand_to_fit()" behavior is acceptable from the perspective of resource allocation. The expansion happens because a conflicting resource range is already populated, which means the resource boundary expansion does not result in any additional free CXL address space being made available. CXL address space allocation is always bounded by the orginal unexpanded address range. However, the potential for expansion does mean that something like walk_iomem_res_desc(IORES_DESC_CXL...) can only return fuzzy answers on corner case platforms that cause the resource tree to expand a CXL window resource over a range that is not decoded by CXL. This would be an odd platform configuration, but if it becomes a problem in practice the CXL subsytem could just publish an API that returns definitive answers. Cc: Andrew Morton Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Tony Luck Cc: Christoph Hellwig Reviewed-by: Jonathan Cameron Acked-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/165784325943.1758207.5310344844375305118.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

kernel/resource: fix kfree() of bootmem memory again

2022-03-24T02:00:35Z

Since commit ebff7d8f270d ("mem hotunplug: fix kfree() of bootmem memory"), we could get a resource allocated during boot via alloc_resource(). And it's required to release the resource using free_resource(). Howerver, many people use kfree directly which will result in kernel BUG. In order to fix this without fixing every call site, just leak a couple of bytes in such corner case. Link: https://lkml.kernel.org/r/20220217083619.19305-1-linmiaohe@huawei.com Fixes: ebff7d8f270d ("mem hotunplug: fix kfree() of bootmem memory") Signed-off-by: Miaohe Lin Suggested-by: David Hildenbrand Cc: Dan Williams Cc: Alistair Popple Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds