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* x86/kaslr: Expose and use the end of the physical memory address spaceThomas Gleixner2024-08-201-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | iounmap() on x86 occasionally fails to unmap because the provided valid ioremap address is not below high_memory. It turned out that this happens due to KASLR. KASLR uses the full address space between PAGE_OFFSET and vaddr_end to randomize the starting points of the direct map, vmalloc and vmemmap regions. It thereby limits the size of the direct map by using the installed memory size plus an extra configurable margin for hot-plug memory. This limitation is done to gain more randomization space because otherwise only the holes between the direct map, vmalloc, vmemmap and vaddr_end would be usable for randomizing. The limited direct map size is not exposed to the rest of the kernel, so the memory hot-plug and resource management related code paths still operate under the assumption that the available address space can be determined with MAX_PHYSMEM_BITS. request_free_mem_region() allocates from (1 << MAX_PHYSMEM_BITS) - 1 downwards. That means the first allocation happens past the end of the direct map and if unlucky this address is in the vmalloc space, which causes high_memory to become greater than VMALLOC_START and consequently causes iounmap() to fail for valid ioremap addresses. MAX_PHYSMEM_BITS cannot be changed for that because the randomization does not align with address bit boundaries and there are other places which actually require to know the maximum number of address bits. All remaining usage sites of MAX_PHYSMEM_BITS have been analyzed and found to be correct. Cure this by exposing the end of the direct map via PHYSMEM_END and use that for the memory hot-plug and resource management related places instead of relying on MAX_PHYSMEM_BITS. In the KASLR case PHYSMEM_END maps to a variable which is initialized by the KASLR initialization and otherwise it is based on MAX_PHYSMEM_BITS as before. To prevent future hickups add a check into add_pages() to catch callers trying to add memory above PHYSMEM_END. Fixes: 0483e1fa6e09 ("x86/mm: Implement ASLR for kernel memory regions") Reported-by: Max Ramanouski <max8rr8@gmail.com> Reported-by: Alistair Popple <apopple@nvidia.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-By: Max Ramanouski <max8rr8@gmail.com> Tested-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Kees Cook <kees@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/87ed6soy3z.ffs@tglx
* resource: Export find_resource_space()Ilpo Järvinen2024-05-281-22/+4
| | | | | | | | | | | | | | | | PCI bridge window logic needs to find out in advance to the actual allocation if there is an empty space big enough to fit the window. Export find_resource_space() for the purpose. Also move the struct resource_constraint into generic header to be able to use the new interface. Link: https://lore.kernel.org/r/20240507102523.57320-7-ilpo.jarvinen@linux.intel.com Tested-by: Lidong Wang <lidong.wang@intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* resource: Handle simple alignment inside __find_resource_space()Ilpo Järvinen2024-05-281-13/+7
| | | | | | | | | | | | | | | | | | | | | allocate_resource() accepts ->alignf() callback to perform custom alignment beyond constraint->align. If alignf is NULL, simple_align_resource() is used which only returns avail->start (no change). Using avail->start directly is natural and can be done with a conditional in __find_resource_space() instead which avoids unnecessarily using callback. It makes the code inside __find_resource_space() more obvious and removes the need for the caller to provide constraint->alignf unnecessarily. This is preparation for exporting find_resource_space(). Link: https://lore.kernel.org/r/20240507102523.57320-6-ilpo.jarvinen@linux.intel.com Tested-by: Lidong Wang <lidong.wang@intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* resource: Use typedef for alignf callbackIlpo Järvinen2024-05-281-6/+2
| | | | | | | | | | | | | To make it simpler to declare resource constraint alignf callbacks, add typedef for it and document it. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20240507102523.57320-5-ilpo.jarvinen@linux.intel.com Tested-by: Lidong Wang <lidong.wang@intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* resource: Document find_resource_space() and resource_constraintIlpo Järvinen2024-05-281-3/+26
| | | | | | | | | | | | Document find_resource_space() and the struct resource_constraint as they are going to be exposed outside of resource.c. Link: https://lore.kernel.org/r/20240507102523.57320-4-ilpo.jarvinen@linux.intel.com Tested-by: Lidong Wang <lidong.wang@intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* resource: Rename find_resource() to find_resource_space()Ilpo Järvinen2024-05-281-12/+11
| | | | | | | | | | | | | Rename find_resource() to find_resource_space() to better describe what the function does. This is a preparation for exposing it beyond resource.c, which is needed by PCI core. Also rename the __ variant to match the names. Link: https://lore.kernel.org/r/20240507102523.57320-3-ilpo.jarvinen@linux.intel.com Tested-by: Lidong Wang <lidong.wang@intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* Merge tag 'mm-nonmm-stable-2024-01-09-10-33' of ↵Linus Torvalds2024-01-091-0/+57
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: "Quite a lot of kexec work this time around. Many singleton patches in many places. The notable patch series are: - nilfs2 folio conversion from Matthew Wilcox in 'nilfs2: Folio conversions for file paths'. - Additional nilfs2 folio conversion from Ryusuke Konishi in 'nilfs2: Folio conversions for directory paths'. - IA64 remnant removal in Heiko Carstens's 'Remove unused code after IA-64 removal'. - Arnd Bergmann has enabled the -Wmissing-prototypes warning everywhere in 'Treewide: enable -Wmissing-prototypes'. This had some followup fixes: - Nathan Chancellor has cleaned up the hexagon build in the series 'hexagon: Fix up instances of -Wmissing-prototypes'. - Nathan also addressed some s390 warnings in 's390: A couple of fixes for -Wmissing-prototypes'. - Arnd Bergmann addresses the same warnings for MIPS in his series 'mips: address -Wmissing-prototypes warnings'. - Baoquan He has made kexec_file operate in a top-down-fitting manner similar to kexec_load in the series 'kexec_file: Load kernel at top of system RAM if required' - Baoquan He has also added the self-explanatory 'kexec_file: print out debugging message if required'. - Some checkstack maintenance work from Tiezhu Yang in the series 'Modify some code about checkstack'. - Douglas Anderson has disentangled the watchdog code's logging when multiple reports are occurring simultaneously. The series is 'watchdog: Better handling of concurrent lockups'. - Yuntao Wang has contributed some maintenance work on the crash code in 'crash: Some cleanups and fixes'" * tag 'mm-nonmm-stable-2024-01-09-10-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (157 commits) crash_core: fix and simplify the logic of crash_exclude_mem_range() x86/crash: use SZ_1M macro instead of hardcoded value x86/crash: remove the unused image parameter from prepare_elf_headers() kdump: remove redundant DEFAULT_CRASH_KERNEL_LOW_SIZE scripts/decode_stacktrace.sh: strip unexpected CR from lines watchdog: if panicking and we dumped everything, don't re-enable dumping watchdog/hardlockup: use printk_cpu_sync_get_irqsave() to serialize reporting watchdog/softlockup: use printk_cpu_sync_get_irqsave() to serialize reporting watchdog/hardlockup: adopt softlockup logic avoiding double-dumps kexec_core: fix the assignment to kimage->control_page x86/kexec: fix incorrect end address passed to kernel_ident_mapping_init() lib/trace_readwrite.c:: replace asm-generic/io with linux/io nilfs2: cpfile: fix some kernel-doc warnings stacktrace: fix kernel-doc typo scripts/checkstack.pl: fix no space expression between sp and offset x86/kexec: fix incorrect argument passed to kexec_dprintk() x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs nilfs2: add missing set_freezable() for freezable kthread kernel: relay: remove relay_file_splice_read dead code, doesn't work docs: submit-checklist: remove all of "make namespacecheck" ...
| * resource: add walk_system_ram_res_rev()Baoquan He2023-12-111-0/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function, being a variant of walk_system_ram_res() introduced in commit 8c86e70acead ("resource: provide new functions to walk through resources"), walks through a list of all the resources of System RAM in reversed order, i.e., from higher to lower. It will be used in kexec_file code to load kernel, initrd etc when preparing kexec reboot. Link: https://lkml.kernel.org/r/ZVTA6z/06cLnWKUz@MiWiFi-R3L-srv Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | kernel/resource: Increment by align value in get_free_mem_region()Alison Schofield2023-12-051-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | 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 <dmytro.adamenko@intel.com> Reported-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231113221324.1118092-1-alison.schofield@intel.com Cc: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* resource: Unify next_resource() and next_resource_skip_children()Andy Shevchenko2023-10-051-13/+6
| | | | | | | | | | | 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 <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230912165312.402422-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* resource: Reuse for_each_resource() macroAndy Shevchenko2023-10-051-15/+19
| | | | | | | | | | | | 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 <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230912165312.402422-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* dax/kmem: Fix leak of memory-hotplug resourcesDan Williams2023-02-171-14/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: <stable@vger.kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/167653656244.3147810.5705900882794040229.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* Merge tag 'driver-core-6.2-rc1' of ↵Linus Torvalds2022-12-161-10/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 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 * ...
| * resource: Replace printk(KERN_WARNING) by pr_warn(), printk() by pr_info()Andy Shevchenko2022-11-101-10/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <andriy.shevchenko@linux.intel.com> Reviewed-by: Rafael J. Wysocki <rafael@kernel.org> Link: https://lore.kernel.org/r/20221109155618.42276-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | PCI: Allow drivers to request exclusive config regionsIra Weiny2022-11-141-5/+8
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <bhelgaas@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Suggested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20220926215711.2893286-2-ira.weiny@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* resource: Introduce alloc_free_mem_region()Dan Williams2022-07-221-35/+143
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <jgg@nvidia.com> Link: https://lore.kernel.org/linux-cxl/20220420143406.GY2120790@nvidia.com/ Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784333333.1758207.13703329337805274043.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* cxl/acpi: Track CXL resources in iomem_resourceDan Williams2022-07-211-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <akpm@linux-foundation.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/165784325943.1758207.5310344844375305118.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* kernel/resource: fix kfree() of bootmem memory againMiaohe Lin2022-03-241-33/+8
| | | | | | | | | | | | | | | | | | 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 <linmiaohe@huawei.com> Suggested-by: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Alistair Popple <apopple@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: remove PDE_DATA() completelyMuchun Song2022-01-221-2/+2
| | | | | | | | | | | | | | | Remove PDE_DATA() completely and replace it with pde_data(). [akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c] [akpm@linux-foundation.org: now fix it properly] Link: https://lkml.kernel.org/r/20211124081956.87711-2-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alexey Gladkov <gladkov.alexey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: disallow access to exclusive system RAM regionsDavid Hildenbrand2021-11-091-10/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | virtio-mem dynamically exposes memory inside a device memory region as system RAM to Linux, coordinating with the hypervisor which parts are actually "plugged" and consequently usable/accessible. On the one hand, the virtio-mem driver adds/removes whole memory blocks, creating/removing busy IORESOURCE_SYSTEM_RAM resources, on the other hand, it logically (un)plugs memory inside added memory blocks, dynamically either exposing them to the buddy or hiding them from the buddy and marking them PG_offline. In contrast to physical devices, like a DIMM, the virtio-mem driver is required to actually make use of any of the device-provided memory, because it performs the handshake with the hypervisor. virtio-mem memory cannot simply be access via /dev/mem without a driver. There is no safe way to: a) Access plugged memory blocks via /dev/mem, as they might contain unplugged holes or might get silently unplugged by the virtio-mem driver and consequently turned inaccessible. b) Access unplugged memory blocks via /dev/mem because the virtio-mem driver is required to make them actually accessible first. The virtio-spec states that unplugged memory blocks MUST NOT be written, and only selected unplugged memory blocks MAY be read. We want to make sure, this is the case in sane environments -- where the virtio-mem driver was loaded. We want to make sure that in a sane environment, nobody "accidentially" accesses unplugged memory inside the device managed region. For example, a user might spot a memory region in /proc/iomem and try accessing it via /dev/mem via gdb or dumping it via something else. By the time the mmap() happens, the memory might already have been removed by the virtio-mem driver silently: the mmap() would succeeed and user space might accidentially access unplugged memory. So once the driver was loaded and detected the device along the device-managed region, we just want to disallow any access via /dev/mem to it. In an ideal world, we would mark the whole region as busy ("owned by a driver") and exclude it; however, that would be wrong, as we don't really have actual system RAM at these ranges added to Linux ("busy system RAM"). Instead, we want to mark such ranges as "not actual busy system RAM but still soft-reserved and prepared by a driver for future use." Let's teach iomem_is_exclusive() to reject access to any range with "IORESOURCE_SYSTEM_RAM | IORESOURCE_EXCLUSIVE", even if not busy and even if "iomem=relaxed" is set. Introduce EXCLUSIVE_SYSTEM_RAM to make it easier for applicable drivers to depend on this setting in their Kconfig. For now, there are no applicable ranges and we'll modify virtio-mem next to properly set IORESOURCE_EXCLUSIVE on the parent resource container it creates to contain all actual busy system RAM added via add_memory_driver_managed(). Link: https://lkml.kernel.org/r/20210920142856.17758-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Jason Wang <jasowang@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: clean up and optimize iomem_is_exclusive()David Hildenbrand2021-11-091-5/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "virtio-mem: disallow mapping virtio-mem memory via /dev/mem", v5. Let's add the basic infrastructure to exclude some physical memory regions marked as "IORESOURCE_SYSTEM_RAM" completely from /dev/mem access, even though they are not marked IORESOURCE_BUSY and even though "iomem=relaxed" is set. Resource IORESOURCE_EXCLUSIVE for that purpose instead of adding new flags to express something similar to "soft-busy" or "not busy yet, but already prepared by a driver and not to be mapped by user space". Use it for virtio-mem, to disallow mapping any virtio-mem memory via /dev/mem to user space after the virtio-mem driver was loaded. This patch (of 3): We end up traversing subtrees of ranges we are not interested in; let's optimize this case, skipping such subtrees, cleaning up the function a bit. For example, in the following configuration (/proc/iomem): 00000000-00000fff : Reserved 00001000-00057fff : System RAM 00058000-00058fff : Reserved 00059000-0009cfff : System RAM 0009d000-000fffff : Reserved 000a0000-000bffff : PCI Bus 0000:00 000c0000-000c3fff : PCI Bus 0000:00 000c4000-000c7fff : PCI Bus 0000:00 000c8000-000cbfff : PCI Bus 0000:00 000cc000-000cffff : PCI Bus 0000:00 000d0000-000d3fff : PCI Bus 0000:00 000d4000-000d7fff : PCI Bus 0000:00 000d8000-000dbfff : PCI Bus 0000:00 000dc000-000dffff : PCI Bus 0000:00 000e0000-000e3fff : PCI Bus 0000:00 000e4000-000e7fff : PCI Bus 0000:00 000e8000-000ebfff : PCI Bus 0000:00 000ec000-000effff : PCI Bus 0000:00 000f0000-000fffff : PCI Bus 0000:00 000f0000-000fffff : System ROM 00100000-3fffffff : System RAM 40000000-403fffff : Reserved 40000000-403fffff : pnp 00:00 40400000-80a79fff : System RAM ... We don't have to look at any children of "0009d000-000fffff : Reserved" if we can just skip these 15 items directly because the parent range is not of interest. Link: https://lkml.kernel.org/r/20210920142856.17758-1-david@redhat.com Link: https://lkml.kernel.org/r/20210920142856.17758-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: fix return code check in __request_free_mem_regionAlistair Popple2021-05-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Splitting an earlier version of a patch that allowed calling __request_region() while holding the resource lock into a series of patches required changing the return code for the newly introduced __request_region_locked(). Unfortunately this change was not carried through to a subsequent commit 56fd94919b8b ("kernel/resource: fix locking in request_free_mem_region") in the series. This resulted in a use-after-free due to freeing the struct resource without properly releasing it. Fix this by correcting the return code check so that the struct is not freed if the request to add it was successful. Link: https://lkml.kernel.org/r/20210512073528.22334-1-apopple@nvidia.com Fixes: 56fd94919b8b ("kernel/resource: fix locking in request_free_mem_region") Signed-off-by: Alistair Popple <apopple@nvidia.com> Reported-by: kernel test robot <oliver.sang@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Muchun Song <smuchun@gmail.com> Cc: Oliver Sang <oliver.sang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: fix locking in request_free_mem_regionAlistair Popple2021-05-071-7/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | request_free_mem_region() is used to find an empty range of physical addresses for hotplugging ZONE_DEVICE memory. It does this by iterating over the range of possible addresses using region_intersects() to see if the range is free before calling request_mem_region() to allocate the region. However the resource_lock is dropped between these two calls meaning by the time request_mem_region() is called in request_free_mem_region() another thread may have already reserved the requested region. This results in unexpected failures and a message in the kernel log from hitting this condition: /* * mm/hmm.c reserves physical addresses which then * become unavailable to other users. Conflicts are * not expected. Warn to aid debugging if encountered. */ if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) { pr_warn("Unaddressable device %s %pR conflicts with %pR", conflict->name, conflict, res); These unexpected failures can be corrected by holding resource_lock across the two calls. This also requires memory allocation to be performed prior to taking the lock. Link: https://lkml.kernel.org/r/20210419070109.4780-3-apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Muchun Song <smuchun@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: refactor __request_region to allow external lockingAlistair Popple2021-05-071-20/+32
| | | | | | | | | | | | | | | | | | Refactor the portion of __request_region() done whilst holding the resource_lock into a separate function to allow callers to hold the lock. Link: https://lkml.kernel.org/r/20210419070109.4780-2-apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Muchun Song <smuchun@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: allow region_intersects users to hold resource_lockAlistair Popple2021-05-071-21/+31
| | | | | | | | | | | | | | | | | | | | | | Introduce a version of region_intersects() that can be called with the resource_lock already held. This will be used in a future fix to __request_free_mem_region(). [akpm@linux-foundation.org: make __region_intersects static] Link: https://lkml.kernel.org/r/20210419070109.4780-1-apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Muchun Song <smuchun@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: remove first_lvl / siblings_only logicDavid Hildenbrand2021-05-071-33/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All functions that search for IORESOURCE_SYSTEM_RAM or IORESOURCE_MEM resources now properly consider the whole resource tree, not just the first level. Let's drop the unused first_lvl / siblings_only logic. Remove documentation that indicates that some functions behave differently, all consider the full resource tree now. Link: https://lkml.kernel.org/r/20210325115326.7826-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Oscar Salvador <osalvador@suse.de> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: make walk_mem_res() find all busy IORESOURCE_MEM resourcesDavid Hildenbrand2021-05-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It used to be true that we can have system RAM (IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY) only on the first level in the resource tree. However, this is no longer holds for driver-managed system RAM (i.e., added via dax/kmem and virtio-mem), which gets added on lower levels, for example, inside device containers. IORESOURCE_SYSTEM_RAM is defined as IORESOURCE_MEM | IORESOURCE_SYSRAM and just a special type of IORESOURCE_MEM. The function walk_mem_res() only considers the first level and is used in arch/x86/mm/ioremap.c:__ioremap_check_mem() only. We currently fail to identify System RAM added by dax/kmem and virtio-mem as "IORES_MAP_SYSTEM_RAM", for example, allowing for remapping of such "normal RAM" in __ioremap_caller(). Let's find all IORESOURCE_MEM | IORESOURCE_BUSY resources, making the function behave similar to walk_system_ram_res(). Link: https://lkml.kernel.org/r/20210325115326.7826-3-david@redhat.com Fixes: ebf71552bb0e ("virtio-mem: Add parent resource for all added "System RAM"") Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Oscar Salvador <osalvador@suse.de> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: make walk_system_ram_res() find all busy ↵David Hildenbrand2021-05-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | IORESOURCE_SYSTEM_RAM resources Patch series "kernel/resource: make walk_system_ram_res() and walk_mem_res() search the whole tree", v2. Playing with kdump+virtio-mem I noticed that kexec_file_load() does not consider System RAM added via dax/kmem and virtio-mem when preparing the elf header for kdump. Looking into the details, the logic used in walk_system_ram_res() and walk_mem_res() seems to be outdated. walk_system_ram_range() already does the right thing, let's change walk_system_ram_res() and walk_mem_res(), and clean up. Loading a kdump kernel via "kexec -p -s" ... will result in the kdump kernel to also dump dax/kmem and virtio-mem added System RAM now. Note: kexec-tools on x86-64 also have to be updated to consider this memory in the kexec_load() case when processing /proc/iomem. This patch (of 3): It used to be true that we can have system RAM (IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY) only on the first level in the resource tree. However, this is no longer holds for driver-managed system RAM (i.e., added via dax/kmem and virtio-mem), which gets added on lower levels, for example, inside device containers. We have two users of walk_system_ram_res(), which currently only consideres the first level: a) kernel/kexec_file.c:kexec_walk_resources() -- We properly skip IORESOURCE_SYSRAM_DRIVER_MANAGED resources via locate_mem_hole_callback(), so even after this change, we won't be placing kexec images onto dax/kmem and virtio-mem added memory. No change. b) arch/x86/kernel/crash.c:fill_up_crash_elf_data() -- we're currently not adding relevant ranges to the crash elf header, resulting in them not getting dumped via kdump. This change fixes loading a crashkernel via kexec_file_load() and including dax/kmem and virtio-mem added System RAM in the crashdump on x86-64. Note that e.g,, arm64 relies on memblock data and, therefore, always considers all added System RAM already. Let's find all IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY resources, making the function behave like walk_system_ram_range(). Link: https://lkml.kernel.org/r/20210325115326.7826-1-david@redhat.com Link: https://lkml.kernel.org/r/20210325115326.7826-2-david@redhat.com Fixes: ebf71552bb0e ("virtio-mem: Add parent resource for all added "System RAM"") Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Oscar Salvador <osalvador@suse.de> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* resource: Move devmem revoke code to resource frameworkDaniel Vetter2021-01-121-1/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want all iomem mmaps to consistently revoke ptes when the kernel takes over and CONFIG_IO_STRICT_DEVMEM is enabled. This includes the pci bar mmaps available through procfs and sysfs, which currently do not revoke mappings. To prepare for this, move the code from the /dev/kmem driver to kernel/resource.c. During review Jason spotted that barriers are used somewhat inconsistently. Fix that up while we shuffle this code, since it doesn't have an actual impact at runtime. Otherwise no semantic and behavioural changes intended, just code extraction and adjusting comments and names. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kees Cook <keescook@chromium.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Hildenbrand <david@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20201127164131.2244124-11-daniel.vetter@ffwll.ch
* kernel/resource.c: fix kernel-doc markupsMauro Carvalho Chehab2020-12-161-10/+14
| | | | | | | | | | | | | | | | | Kernel-doc markups should use this format: identifier - description While here, fix a kernel-doc tag that was using, instead, a normal comment block. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/c5e38e1070f8dbe2f9607a10b44afe2875bd966c.1605521731.git.mchehab+huawei@kernel.org Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: "Jonathan Corbet" <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* resource: Simplify region_intersects() by reducing conditionalsAndy Shevchenko2020-11-171-5/+5
| | | | | | | | | | | | | | | | | | Now we have for 'other' and 'type' variables other type return 0 0 REGION_DISJOINT 0 x REGION_INTERSECTS x 0 REGION_DISJOINT x x REGION_MIXED Obviously it's easier to check 'type' for 0 first instead of currently checked 'other'. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Tested-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* kernel/resource: make iomem_resource implicit in release_mem_region_adjustable()David Hildenbrand2020-10-161-3/+2
| | | | | | | | | | | | | | | | | | | | | "mem" in the name already indicates the root, similar to release_mem_region() and devm_request_mem_region(). Make it implicit. The only single caller always passes iomem_resource, other parents are not applicable. Suggested-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kees Cook <keescook@chromium.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Baoquan He <bhe@redhat.com> Link: https://lkml.kernel.org/r/20200916073041.10355-1-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM ↵David Hildenbrand2020-10-161-0/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | resources Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where possible. Let's provide a flag (MEMHP_MERGE_RESOURCE) to specify that a resource either created within add_memory*() or passed via add_memory_resource() shall be marked mergeable and merged with applicable siblings. To implement that, we need a kernel/resource interface to mark selected System RAM resources mergeable (IORESOURCE_SYSRAM_MERGEABLE) and trigger merging. Note: We really want to merge after the whole operation succeeded, not directly when adding a resource to the resource tree (it would break add_memory_resource() and require splitting resources again when the operation failed - e.g., due to -ENOMEM). Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kees Cook <keescook@chromium.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Wei Liu <wei.liu@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Roger Pau Monné <roger.pau@citrix.com> Cc: Julien Grall <julien@xen.org> Cc: Baoquan He <bhe@redhat.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Len Brown <lenb@kernel.org> Cc: Leonardo Bras <leobras.c@gmail.com> Cc: Libor Pechacek <lpechacek@suse.cz> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: "Oliver O'Halloran" <oohall@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pingfan Liu <kernelfans@gmail.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Link: https://lkml.kernel.org/r/20200911103459.10306-6-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/resource: make release_mem_region_adjustable() never failDavid Hildenbrand2020-10-161-21/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "selective merging of system ram resources", v4. Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where possible. Resources are effectively stored in a list-based tree. Having a lot of resources not only wastes memory, it also makes traversing that tree more expensive, and makes /proc/iomem explode in size (e.g., requiring kexec-tools to manually merge resources when creating a kdump header. The current kexec-tools resource count limit does not allow for more than ~100GB of memory with a memory block size of 128MB on x86-64). Let's allow to selectively merge system ram resources by specifying a new flag for add_memory*(). Patch #5 contains a /proc/iomem example. Only tested with virtio-mem. This patch (of 8): Let's make sure splitting a resource on memory hotunplug will never fail. This will become more relevant once we merge selected System RAM resources - then, we'll trigger that case more often on memory hotunplug. In general, this function is already unlikely to fail. When we remove memory, we free up quite a lot of metadata (memmap, page tables, memory block device, etc.). The only reason it could really fail would be when injecting allocation errors. All other error cases inside release_mem_region_adjustable() seem to be sanity checks if the function would be abused in different context - let's add WARN_ON_ONCE() in these cases so we can catch them. [natechancellor@gmail.com: fix use of ternary condition in release_mem_region_adjustable] Link: https://lkml.kernel.org/r/20200922060748.2452056-1-natechancellor@gmail.com Link: https://github.com/ClangBuiltLinux/linux/issues/1159 Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kees Cook <keescook@chromium.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Julien Grall <julien@xen.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Len Brown <lenb@kernel.org> Cc: Leonardo Bras <leobras.c@gmail.com> Cc: Libor Pechacek <lpechacek@suse.cz> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: "Oliver O'Halloran" <oohall@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pingfan Liu <kernelfans@gmail.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Roger Pau Monn <roger.pau@citrix.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Wei Liu <wei.liu@kernel.org> Link: https://lkml.kernel.org/r/20200911103459.10306-2-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* resource: report parent to walk_iomem_res_desc() callbackDan Williams2020-10-141-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In support of detecting whether a resource might have been been claimed, report the parent to the walk_iomem_res_desc() callback. For example, the ACPI HMAT parser publishes "hmem" platform devices per target range. However, if the HMAT is disabled / missing a fallback driver can attach devices to the raw memory ranges as a fallback if it sees unclaimed / orphan "Soft Reserved" resources in the resource tree. Otherwise, find_next_iomem_res() returns a resource with garbage data from the stack allocation in __walk_iomem_res_desc() for the res->parent field. There are currently no users that expect ->child and ->sibling to be valid, and the resource_lock would be needed to traverse them. Use a compound literal to implicitly zero initialize the fields that are not being returned in addition to setting ->parent. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brice Goglin <Brice.Goglin@inria.fr> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jia He <justin.he@arm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Hulk Robot <hulkci@huawei.com> Cc: Jason Yan <yanaijie@huawei.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: kernel test robot <lkp@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Link: https://lkml.kernel.org/r/159643097166.4062302.11875688887228572793.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* /dev/mem: Revoke mappings when a driver claims the regionDan Williams2020-05-271-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Close the hole of holding a mapping over kernel driver takeover event of a given address range. Commit 90a545e98126 ("restrict /dev/mem to idle io memory ranges") introduced CONFIG_IO_STRICT_DEVMEM with the goal of protecting the kernel against scenarios where a /dev/mem user tramples memory that a kernel driver owns. However, this protection only prevents *new* read(), write() and mmap() requests. Established mappings prior to the driver calling request_mem_region() are left alone. Especially with persistent memory, and the core kernel metadata that is stored there, there are plentiful scenarios for a /dev/mem user to violate the expectations of the driver and cause amplified damage. Teach request_mem_region() to find and shoot down active /dev/mem mappings that it believes it has successfully claimed for the exclusive use of the driver. Effectively a driver call to request_mem_region() becomes a hole-punch on the /dev/mem device. The typical usage of unmap_mapping_range() is part of truncate_pagecache() to punch a hole in a file, but in this case the implementation is only doing the "first half" of a hole punch. Namely it is just evacuating current established mappings of the "hole", and it relies on the fact that /dev/mem establishes mappings in terms of absolute physical address offsets. Once existing mmap users are invalidated they can attempt to re-establish the mapping, or attempt to continue issuing read(2) / write(2) to the invalidated extent, but they will then be subject to the CONFIG_IO_STRICT_DEVMEM checking that can block those subsequent accesses. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes: 90a545e98126 ("restrict /dev/mem to idle io memory ranges") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/159009507306.847224.8502634072429766747.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* mm/memory_hotplug.c: use PFN_UP / PFN_DOWN in walk_system_ram_range()David Hildenbrand2019-09-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm/memory_hotplug: online_pages() cleanups", v2. Some cleanups (+ one fix for a special case) in the context of online_pages(). This patch (of 5): This makes it clearer that we will never call func() with duplicate PFNs in case we have multiple sub-page memory resources. All unaligned parts of PFNs are completely discarded. Link: http://lkml.kernel.org/r/20190814154109.3448-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Arun KS <arunks@codeaurora.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* resource: add a not device managed request_free_mem_region variantChristoph Hellwig2019-08-201-14/+31
| | | | | | | | | | | | | | Factor out the guts of devm_request_free_mem_region so that we can implement both a device managed and a manually release version as tiny wrappers around it. Link: https://lore.kernel.org/r/20190818090557.17853-2-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Bharata B Rao <bharata@linux.ibm.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* resource: avoid unnecessary lookups in find_next_iomem_res()Nadav Amit2019-07-191-7/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | find_next_iomem_res() shows up to be a source for overhead in dax benchmarks. Improve performance by not considering children of the tree if the top level does not match. Since the range of the parents should include the range of the children such check is redundant. Running sysbench on dax (pmem emulation, with write_cache disabled): sysbench fileio --file-total-size=3G --file-test-mode=rndwr \ --file-io-mode=mmap --threads=4 --file-fsync-mode=fdatasync run Provides the following results: events (avg/stddev) ------------------- 5.2-rc3: 1247669.0000/16075.39 w/patch: 1286320.5000/16402.72 (+3%) Link: http://lkml.kernel.org/r/20190613045903.4922-3-namit@vmware.com Signed-off-by: Nadav Amit <namit@vmware.com> Cc: Borislav Petkov <bp@suse.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* resource: fix locking in find_next_iomem_res()Nadav Amit2019-07-191-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | Since resources can be removed, locking should ensure that the resource is not removed while accessing it. However, find_next_iomem_res() does not hold the lock while copying the data of the resource. Keep holding the lock while the data is copied. While at it, change the return value to a more informative value. It is disregarded by the callers. [akpm@linux-foundation.org: fix find_next_iomem_res() documentation] Link: http://lkml.kernel.org/r/20190613045903.4922-2-namit@vmware.com Fixes: ff3cc952d3f00 ("resource: Add remove_resource interface") Signed-off-by: Nadav Amit <namit@vmware.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: factor out a devm_request_free_mem_region helperChristoph Hellwig2019-07-021-0/+39
| | | | | | | | | | | | Keep the physical address allocation that hmm_add_device does with the rest of the resource code, and allow future reuse of it without the hmm wrapper. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* treewide: Add SPDX license identifier for missed filesThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* mm/resource: Use resource_overlaps() to simplify region_intersects()Wei Yang2019-04-191-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | The three checks in region_intersects() are basically an open-coded version of resource_overlaps() - so use the real thing. Also fix typos in comments while at it. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Like Xu <like.xu@linux.intel.com> Reviewed-by: Yuan Yao <yuan.yao@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: bhelgaas@google.com Cc: bp@suse.de Cc: dan.j.williams@intel.com Cc: jack@suse.cz Cc: rdunlap@infradead.org Cc: tiwai@suse.de Link: http://lkml.kernel.org/r/20190305083432.23675-1-richardw.yang@linux.intel.com [ Rewrote the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'devdax-for-5.1' of ↵Linus Torvalds2019-03-161-3/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull device-dax updates from Dan Williams: "New device-dax infrastructure to allow persistent memory and other "reserved" / performance differentiated memories, to be assigned to the core-mm as "System RAM". Some users want to use persistent memory as additional volatile memory. They are willing to cope with potential performance differences, for example between DRAM and 3D Xpoint, and want to use typical Linux memory management apis rather than a userspace memory allocator layered over an mmap() of a dax file. The administration model is to decide how much Persistent Memory (pmem) to use as System RAM, create a device-dax-mode namespace of that size, and then assign it to the core-mm. The rationale for device-dax is that it is a generic memory-mapping driver that can be layered over any "special purpose" memory, not just pmem. On subsequent boots udev rules can be used to restore the memory assignment. One implication of using pmem as RAM is that mlock() no longer keeps data off persistent media. For this reason it is recommended to enable NVDIMM Security (previously merged for 5.0) to encrypt pmem contents at rest. We considered making this recommendation an actively enforced requirement, but in the end decided to leave it as a distribution / administrator policy to allow for emulation and test environments that lack security capable NVDIMMs. Summary: - Replace the /sys/class/dax device model with /sys/bus/dax, and include a compat driver so distributions can opt-in to the new ABI. - Allow for an alternative driver for the device-dax address-range - Introduce the 'kmem' driver to hotplug / assign a device-dax address-range to the core-mm. - Arrange for the device-dax target-node to be onlined so that the newly added memory range can be uniquely referenced by numa apis" NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because we currently have special - and very annoying rules in the kernel about accessing PMEM only with the "MC safe" accessors, because machine checks inside the regular repeat string copy functions can be fatal in some (not described) circumstances. And apparently the PMEM modules can cause that a lot more than regular RAM. The argument is that this happens because PMEM doesn't necessarily get scrubbed at boot like RAM does, but that is planned to be added for the user space tooling. Quoting Dan from another email: "The exposure can be reduced in the volatile-RAM case by scanning for and clearing errors before it is onlined as RAM. The userspace tooling for that can be in place before v5.1-final. There's also runtime notifications of errors via acpi_nfit_uc_error_notify() from background scrubbers on the DIMM devices. With that mechanism the kernel could proactively clear newly discovered poison in the volatile case, but that would be additional development more suitable for v5.2. I understand the concern, and the need to highlight this issue by tapping the brakes on feature development, but I don't see PMEM as RAM making the situation worse when the exposure is also there via DAX in the PMEM case. Volatile-RAM is arguably a safer use case since it's possible to repair pages where the persistent case needs active application coordination" * tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: device-dax: "Hotplug" persistent memory for use like normal RAM mm/resource: Let walk_system_ram_range() search child resources mm/memory-hotplug: Allow memory resources to be children mm/resource: Move HMM pr_debug() deeper into resource code mm/resource: Return real error codes from walk failures device-dax: Add a 'modalias' attribute to DAX 'bus' devices device-dax: Add a 'target_node' attribute device-dax: Auto-bind device after successful new_id acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node device-dax: Add /sys/class/dax backwards compatibility device-dax: Add support for a dax override driver device-dax: Move resource pinning+mapping into the common driver device-dax: Introduce bus + driver model device-dax: Start defining a dax bus model device-dax: Remove multi-resource infrastructure device-dax: Kill dax_region base device-dax: Kill dax_region ida
| * mm/resource: Let walk_system_ram_range() search child resourcesDave Hansen2019-02-281-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the process of onlining memory, we use walk_system_ram_range() to find the actual RAM areas inside of the area being onlined. However, it currently only finds memory resources which are "top-level" iomem_resources. Children are not currently searched which causes it to skip System RAM in areas like this (in the format of /proc/iomem): a0000000-bfffffff : Persistent Memory (legacy) a0000000-afffffff : System RAM Changing the true->false here allows children to be searched as well. We need this because we add a new "System RAM" resource underneath the "persistent memory" resource when we use persistent memory in a volatile mode. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying <ying.huang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Jerome Glisse <jglisse@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * mm/resource: Move HMM pr_debug() deeper into resource codeDave Hansen2019-02-281-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | HMM consumes physical address space for its own use, even though nothing is mapped or accessible there. It uses a special resource description (IORES_DESC_DEVICE_PRIVATE_MEMORY) to uniquely identify these areas. When HMM consumes address space, it makes a best guess about what to consume. However, it is possible that a future memory or device hotplug can collide with the reserved area. In the case of these conflicts, there is an error message in register_memory_resource(). Later patches in this series move register_memory_resource() from using request_resource_conflict() to __request_region(). Unfortunately, __request_region() does not return the conflict like the previous function did, which makes it impossible to check for IORES_DESC_DEVICE_PRIVATE_MEMORY in a conflicting resource. Instead of warning in register_memory_resource(), move the check into the core resource code itself (__request_region()) where the conflicting resource _is_ available. This has the added bonus of producing a warning in case of HMM conflicts with devices *or* RAM address space, as opposed to the RAM- only warnings that were there previously. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jerome Glisse <jglisse@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying <ying.huang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Keith Busch <keith.busch@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * mm/resource: Return real error codes from walk failuresDave Hansen2019-02-281-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | walk_system_ram_range() can return an error code either becuase *it* failed, or because the 'func' that it calls returned an error. The memory hotplug does the following: ret = walk_system_ram_range(..., func); if (ret) return ret; and 'ret' makes it out to userspace, eventually. The problem s, walk_system_ram_range() failues that result from *it* failing (as opposed to 'func') return -1. That leads to a very odd -EPERM (-1) return code out to userspace. Make walk_system_ram_range() return -EINVAL for internal failures to keep userspace less confused. This return code is compatible with all the callers that I audited. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying <ying.huang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@lists.ozlabs.org Cc: Keith Busch <keith.busch@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | powerpc: Drop page_is_ram() and walk_system_ram_range()Christophe Leroy2019-02-041-4/+0
|/ | | | | | | | | | | | | | | | | | Since commit c40dd2f76644 ("powerpc: Add System RAM to /proc/iomem") it is possible to use the generic walk_system_ram_range() and the generic page_is_ram(). To enable the use of walk_system_ram_range() by the IBM EHEA ethernet driver, we still need an export of the generic function. As powerpc was the only user of CONFIG_ARCH_HAS_WALK_MEMORY, the ifdef around the generic walk_system_ram_range() has become useless and can be dropped. Fixes: c40dd2f76644 ("powerpc: Add System RAM to /proc/iomem") Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Keep the EXPORT_SYMBOL_GPL in powerpc code] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustableOscar Salvador2018-12-281-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a preparation for the next patch. Currently, we only call release_mem_region_adjustable() in __remove_pages if the zone is not ZONE_DEVICE, because resources that belong to HMM/devm are being released by themselves with devm_release_mem_region. Since we do not want to touch any zone/page stuff during the removing of the memory (but during the offlining), we do not want to check for the zone here. So we need another way to tell release_mem_region_adjustable() to not realease the resource in case it belongs to HMM/devm. HMM/devm acquires/releases a resource through devm_request_mem_region/devm_release_mem_region. These resources have the flag IORESOURCE_MEM, while resources acquired by hot-add memory path (register_memory_resource()) contain IORESOURCE_SYSTEM_RAM. So, we can check for this flag in release_mem_region_adjustable, and if the resource does not contain such flag, we know that we are dealing with a HMM/devm resource, so we can back off. Link: http://lkml.kernel.org/r/20181127162005.15833-3-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* resource/docs: Complete kernel-doc style function documentationBorislav Petkov2018-11-071-9/+14
| | | | | | | | | | | | | | | Add the missing kernel-doc style function parameters documentation. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: linux-tip-commits@vger.kernel.org Cc: rdunlap@infradead.org Fixes: b69c2e20f6e4 ("resource: Clean it up a bit") Link: http://lkml.kernel.org/r/20181105093307.GA12445@zn.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>