1c221c0b0SDave Hansen // SPDX-License-Identifier: GPL-2.0 2c221c0b0SDave Hansen /* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */ 3c221c0b0SDave Hansen #include <linux/memremap.h> 4c221c0b0SDave Hansen #include <linux/pagemap.h> 5c221c0b0SDave Hansen #include <linux/memory.h> 6c221c0b0SDave Hansen #include <linux/module.h> 7c221c0b0SDave Hansen #include <linux/device.h> 8c221c0b0SDave Hansen #include <linux/pfn_t.h> 9c221c0b0SDave Hansen #include <linux/slab.h> 10c221c0b0SDave Hansen #include <linux/dax.h> 11c221c0b0SDave Hansen #include <linux/fs.h> 12c221c0b0SDave Hansen #include <linux/mm.h> 13c221c0b0SDave Hansen #include <linux/mman.h> 14c221c0b0SDave Hansen #include "dax-private.h" 15c221c0b0SDave Hansen #include "bus.h" 16c221c0b0SDave Hansen 17c221c0b0SDave Hansen int dev_dax_kmem_probe(struct device *dev) 18c221c0b0SDave Hansen { 19c221c0b0SDave Hansen struct dev_dax *dev_dax = to_dev_dax(dev); 20c221c0b0SDave Hansen struct resource *res = &dev_dax->region->res; 21c221c0b0SDave Hansen resource_size_t kmem_start; 22c221c0b0SDave Hansen resource_size_t kmem_size; 23c221c0b0SDave Hansen resource_size_t kmem_end; 24c221c0b0SDave Hansen struct resource *new_res; 2560858c00SDavid Hildenbrand const char *new_res_name; 26c221c0b0SDave Hansen int numa_node; 27c221c0b0SDave Hansen int rc; 28c221c0b0SDave Hansen 29c221c0b0SDave Hansen /* 30c221c0b0SDave Hansen * Ensure good NUMA information for the persistent memory. 31c221c0b0SDave Hansen * Without this check, there is a risk that slow memory 32c221c0b0SDave Hansen * could be mixed in a node with faster memory, causing 33c221c0b0SDave Hansen * unavoidable performance issues. 34c221c0b0SDave Hansen */ 35c221c0b0SDave Hansen numa_node = dev_dax->target_node; 36c221c0b0SDave Hansen if (numa_node < 0) { 37c221c0b0SDave Hansen dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n", 38c221c0b0SDave Hansen res, numa_node); 39c221c0b0SDave Hansen return -EINVAL; 40c221c0b0SDave Hansen } 41c221c0b0SDave Hansen 42c221c0b0SDave Hansen /* Hotplug starting at the beginning of the next block: */ 43c221c0b0SDave Hansen kmem_start = ALIGN(res->start, memory_block_size_bytes()); 44c221c0b0SDave Hansen 45c221c0b0SDave Hansen kmem_size = resource_size(res); 46c221c0b0SDave Hansen /* Adjust the size down to compensate for moving up kmem_start: */ 47c221c0b0SDave Hansen kmem_size -= kmem_start - res->start; 48c221c0b0SDave Hansen /* Align the size down to cover only complete blocks: */ 49c221c0b0SDave Hansen kmem_size &= ~(memory_block_size_bytes() - 1); 50c221c0b0SDave Hansen kmem_end = kmem_start + kmem_size; 51c221c0b0SDave Hansen 5260858c00SDavid Hildenbrand new_res_name = kstrdup(dev_name(dev), GFP_KERNEL); 5360858c00SDavid Hildenbrand if (!new_res_name) 5460858c00SDavid Hildenbrand return -ENOMEM; 5560858c00SDavid Hildenbrand 5660858c00SDavid Hildenbrand /* Region is permanently reserved if hotremove fails. */ 5760858c00SDavid Hildenbrand new_res = request_mem_region(kmem_start, kmem_size, new_res_name); 58c221c0b0SDave Hansen if (!new_res) { 59c221c0b0SDave Hansen dev_warn(dev, "could not reserve region [%pa-%pa]\n", 60c221c0b0SDave Hansen &kmem_start, &kmem_end); 6160858c00SDavid Hildenbrand kfree(new_res_name); 62c221c0b0SDave Hansen return -EBUSY; 63c221c0b0SDave Hansen } 64c221c0b0SDave Hansen 65c221c0b0SDave Hansen /* 66c221c0b0SDave Hansen * Set flags appropriate for System RAM. Leave ..._BUSY clear 67c221c0b0SDave Hansen * so that add_memory() can add a child resource. Do not 68c221c0b0SDave Hansen * inherit flags from the parent since it may set new flags 69c221c0b0SDave Hansen * unknown to us that will break add_memory() below. 70c221c0b0SDave Hansen */ 71c221c0b0SDave Hansen new_res->flags = IORESOURCE_SYSTEM_RAM; 72c221c0b0SDave Hansen 73c221c0b0SDave Hansen rc = add_memory(numa_node, new_res->start, resource_size(new_res)); 7431e4ca92SPavel Tatashin if (rc) { 7531e4ca92SPavel Tatashin release_resource(new_res); 7631e4ca92SPavel Tatashin kfree(new_res); 7760858c00SDavid Hildenbrand kfree(new_res_name); 78c221c0b0SDave Hansen return rc; 7931e4ca92SPavel Tatashin } 809f960da7SPavel Tatashin dev_dax->dax_kmem_res = new_res; 81c221c0b0SDave Hansen 82c221c0b0SDave Hansen return 0; 83c221c0b0SDave Hansen } 84c221c0b0SDave Hansen 859f960da7SPavel Tatashin #ifdef CONFIG_MEMORY_HOTREMOVE 869f960da7SPavel Tatashin static int dev_dax_kmem_remove(struct device *dev) 879f960da7SPavel Tatashin { 889f960da7SPavel Tatashin struct dev_dax *dev_dax = to_dev_dax(dev); 899f960da7SPavel Tatashin struct resource *res = dev_dax->dax_kmem_res; 909f960da7SPavel Tatashin resource_size_t kmem_start = res->start; 919f960da7SPavel Tatashin resource_size_t kmem_size = resource_size(res); 9260858c00SDavid Hildenbrand const char *res_name = res->name; 939f960da7SPavel Tatashin int rc; 949f960da7SPavel Tatashin 959f960da7SPavel Tatashin /* 969f960da7SPavel Tatashin * We have one shot for removing memory, if some memory blocks were not 979f960da7SPavel Tatashin * offline prior to calling this function remove_memory() will fail, and 989f960da7SPavel Tatashin * there is no way to hotremove this memory until reboot because device 999f960da7SPavel Tatashin * unbind will succeed even if we return failure. 1009f960da7SPavel Tatashin */ 1019f960da7SPavel Tatashin rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size); 1029f960da7SPavel Tatashin if (rc) { 1039f960da7SPavel Tatashin dev_err(dev, 1049f960da7SPavel Tatashin "DAX region %pR cannot be hotremoved until the next reboot\n", 1059f960da7SPavel Tatashin res); 1069f960da7SPavel Tatashin return rc; 1079f960da7SPavel Tatashin } 1089f960da7SPavel Tatashin 1099f960da7SPavel Tatashin /* Release and free dax resources */ 1109f960da7SPavel Tatashin release_resource(res); 1119f960da7SPavel Tatashin kfree(res); 11260858c00SDavid Hildenbrand kfree(res_name); 1139f960da7SPavel Tatashin dev_dax->dax_kmem_res = NULL; 1149f960da7SPavel Tatashin 1159f960da7SPavel Tatashin return 0; 1169f960da7SPavel Tatashin } 1179f960da7SPavel Tatashin #else 118c221c0b0SDave Hansen static int dev_dax_kmem_remove(struct device *dev) 119c221c0b0SDave Hansen { 120c221c0b0SDave Hansen /* 1219f960da7SPavel Tatashin * Without hotremove purposely leak the request_mem_region() for the 1229f960da7SPavel Tatashin * device-dax range and return '0' to ->remove() attempts. The removal 1239f960da7SPavel Tatashin * of the device from the driver always succeeds, but the region is 1249f960da7SPavel Tatashin * permanently pinned as reserved by the unreleased 125c221c0b0SDave Hansen * request_mem_region(). 126c221c0b0SDave Hansen */ 127c221c0b0SDave Hansen return 0; 128c221c0b0SDave Hansen } 1299f960da7SPavel Tatashin #endif /* CONFIG_MEMORY_HOTREMOVE */ 130c221c0b0SDave Hansen 131c221c0b0SDave Hansen static struct dax_device_driver device_dax_kmem_driver = { 132c221c0b0SDave Hansen .drv = { 133c221c0b0SDave Hansen .probe = dev_dax_kmem_probe, 134c221c0b0SDave Hansen .remove = dev_dax_kmem_remove, 135c221c0b0SDave Hansen }, 136c221c0b0SDave Hansen }; 137c221c0b0SDave Hansen 138c221c0b0SDave Hansen static int __init dax_kmem_init(void) 139c221c0b0SDave Hansen { 140c221c0b0SDave Hansen return dax_driver_register(&device_dax_kmem_driver); 141c221c0b0SDave Hansen } 142c221c0b0SDave Hansen 143c221c0b0SDave Hansen static void __exit dax_kmem_exit(void) 144c221c0b0SDave Hansen { 145c221c0b0SDave Hansen dax_driver_unregister(&device_dax_kmem_driver); 146c221c0b0SDave Hansen } 147c221c0b0SDave Hansen 148c221c0b0SDave Hansen MODULE_AUTHOR("Intel Corporation"); 149c221c0b0SDave Hansen MODULE_LICENSE("GPL v2"); 150c221c0b0SDave Hansen module_init(dax_kmem_init); 151c221c0b0SDave Hansen module_exit(dax_kmem_exit); 152c221c0b0SDave Hansen MODULE_ALIAS_DAX_DEVICE(0); 153