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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */
3#include <linux/memremap.h>
4#include <linux/pagemap.h>
5#include <linux/memory.h>
6#include <linux/module.h>
7#include <linux/device.h>
8#include <linux/pfn_t.h>
9#include <linux/slab.h>
10#include <linux/dax.h>
11#include <linux/fs.h>
12#include <linux/mm.h>
13#include <linux/mman.h>
14#include <linux/memory-tiers.h>
15#include "dax-private.h"
16#include "bus.h"
17
18/*
19 * Default abstract distance assigned to the NUMA node onlined
20 * by DAX/kmem if the low level platform driver didn't initialize
21 * one for this NUMA node.
22 */
23#define MEMTIER_DEFAULT_DAX_ADISTANCE (MEMTIER_ADISTANCE_DRAM * 5)
24
25/* Memory resource name used for add_memory_driver_managed(). */
26static const char *kmem_name;
27/* Set if any memory will remain added when the driver will be unloaded. */
28static bool any_hotremove_failed;
29
30static int dax_kmem_range(struct dev_dax *dev_dax, int i, struct range *r)
31{
32 struct dev_dax_range *dax_range = &dev_dax->ranges[i];
33 struct range *range = &dax_range->range;
34
35 /* memory-block align the hotplug range */
36 r->start = ALIGN(range->start, memory_block_size_bytes());
37 r->end = ALIGN_DOWN(range->end + 1, memory_block_size_bytes()) - 1;
38 if (r->start >= r->end) {
39 r->start = range->start;
40 r->end = range->end;
41 return -ENOSPC;
42 }
43 return 0;
44}
45
46struct dax_kmem_data {
47 const char *res_name;
48 int mgid;
49 struct resource *res[];
50};
51
52static struct memory_dev_type *dax_slowmem_type;
53static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
54{
55 struct device *dev = &dev_dax->dev;
56 unsigned long total_len = 0;
57 struct dax_kmem_data *data;
58 int i, rc, mapped = 0;
59 int numa_node;
60
61 /*
62 * Ensure good NUMA information for the persistent memory.
63 * Without this check, there is a risk that slow memory
64 * could be mixed in a node with faster memory, causing
65 * unavoidable performance issues.
66 */
67 numa_node = dev_dax->target_node;
68 if (numa_node < 0) {
69 dev_warn(dev, "rejecting DAX region with invalid node: %d\n",
70 numa_node);
71 return -EINVAL;
72 }
73
74 for (i = 0; i < dev_dax->nr_range; i++) {
75 struct range range;
76
77 rc = dax_kmem_range(dev_dax, i, &range);
78 if (rc) {
79 dev_info(dev, "mapping%d: %#llx-%#llx too small after alignment\n",
80 i, range.start, range.end);
81 continue;
82 }
83 total_len += range_len(&range);
84 }
85
86 if (!total_len) {
87 dev_warn(dev, "rejecting DAX region without any memory after alignment\n");
88 return -EINVAL;
89 }
90
91 init_node_memory_type(numa_node, dax_slowmem_type);
92
93 rc = -ENOMEM;
94 data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL);
95 if (!data)
96 goto err_dax_kmem_data;
97
98 data->res_name = kstrdup(dev_name(dev), GFP_KERNEL);
99 if (!data->res_name)
100 goto err_res_name;
101
102 rc = memory_group_register_static(numa_node, total_len);
103 if (rc < 0)
104 goto err_reg_mgid;
105 data->mgid = rc;
106
107 for (i = 0; i < dev_dax->nr_range; i++) {
108 struct resource *res;
109 struct range range;
110
111 rc = dax_kmem_range(dev_dax, i, &range);
112 if (rc)
113 continue;
114
115 /* Region is permanently reserved if hotremove fails. */
116 res = request_mem_region(range.start, range_len(&range), data->res_name);
117 if (!res) {
118 dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n",
119 i, range.start, range.end);
120 /*
121 * Once some memory has been onlined we can't
122 * assume that it can be un-onlined safely.
123 */
124 if (mapped)
125 continue;
126 rc = -EBUSY;
127 goto err_request_mem;
128 }
129 data->res[i] = res;
130
131 /*
132 * Set flags appropriate for System RAM. Leave ..._BUSY clear
133 * so that add_memory() can add a child resource. Do not
134 * inherit flags from the parent since it may set new flags
135 * unknown to us that will break add_memory() below.
136 */
137 res->flags = IORESOURCE_SYSTEM_RAM;
138
139 /*
140 * Ensure that future kexec'd kernels will not treat
141 * this as RAM automatically.
142 */
143 rc = add_memory_driver_managed(data->mgid, range.start,
144 range_len(&range), kmem_name, MHP_NID_IS_MGID);
145
146 if (rc) {
147 dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",
148 i, range.start, range.end);
149 release_resource(res);
150 kfree(res);
151 data->res[i] = NULL;
152 if (mapped)
153 continue;
154 goto err_request_mem;
155 }
156 mapped++;
157 }
158
159 dev_set_drvdata(dev, data);
160
161 return 0;
162
163err_request_mem:
164 memory_group_unregister(data->mgid);
165err_reg_mgid:
166 kfree(data->res_name);
167err_res_name:
168 kfree(data);
169err_dax_kmem_data:
170 clear_node_memory_type(numa_node, dax_slowmem_type);
171 return rc;
172}
173
174#ifdef CONFIG_MEMORY_HOTREMOVE
175static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
176{
177 int i, success = 0;
178 int node = dev_dax->target_node;
179 struct device *dev = &dev_dax->dev;
180 struct dax_kmem_data *data = dev_get_drvdata(dev);
181
182 /*
183 * We have one shot for removing memory, if some memory blocks were not
184 * offline prior to calling this function remove_memory() will fail, and
185 * there is no way to hotremove this memory until reboot because device
186 * unbind will succeed even if we return failure.
187 */
188 for (i = 0; i < dev_dax->nr_range; i++) {
189 struct range range;
190 int rc;
191
192 rc = dax_kmem_range(dev_dax, i, &range);
193 if (rc)
194 continue;
195
196 rc = remove_memory(range.start, range_len(&range));
197 if (rc == 0) {
198 release_resource(data->res[i]);
199 kfree(data->res[i]);
200 data->res[i] = NULL;
201 success++;
202 continue;
203 }
204 any_hotremove_failed = true;
205 dev_err(dev,
206 "mapping%d: %#llx-%#llx cannot be hotremoved until the next reboot\n",
207 i, range.start, range.end);
208 }
209
210 if (success >= dev_dax->nr_range) {
211 memory_group_unregister(data->mgid);
212 kfree(data->res_name);
213 kfree(data);
214 dev_set_drvdata(dev, NULL);
215 /*
216 * Clear the memtype association on successful unplug.
217 * If not, we have memory blocks left which can be
218 * offlined/onlined later. We need to keep memory_dev_type
219 * for that. This implies this reference will be around
220 * till next reboot.
221 */
222 clear_node_memory_type(node, dax_slowmem_type);
223 }
224}
225#else
226static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
227{
228 /*
229 * Without hotremove purposely leak the request_mem_region() for the
230 * device-dax range and return '0' to ->remove() attempts. The removal
231 * of the device from the driver always succeeds, but the region is
232 * permanently pinned as reserved by the unreleased
233 * request_mem_region().
234 */
235 any_hotremove_failed = true;
236}
237#endif /* CONFIG_MEMORY_HOTREMOVE */
238
239static struct dax_device_driver device_dax_kmem_driver = {
240 .probe = dev_dax_kmem_probe,
241 .remove = dev_dax_kmem_remove,
242};
243
244static int __init dax_kmem_init(void)
245{
246 int rc;
247
248 /* Resource name is permanently allocated if any hotremove fails. */
249 kmem_name = kstrdup_const("System RAM (kmem)", GFP_KERNEL);
250 if (!kmem_name)
251 return -ENOMEM;
252
253 dax_slowmem_type = alloc_memory_type(MEMTIER_DEFAULT_DAX_ADISTANCE);
254 if (IS_ERR(dax_slowmem_type)) {
255 rc = PTR_ERR(dax_slowmem_type);
256 goto err_dax_slowmem_type;
257 }
258
259 rc = dax_driver_register(&device_dax_kmem_driver);
260 if (rc)
261 goto error_dax_driver;
262
263 return rc;
264
265error_dax_driver:
266 destroy_memory_type(dax_slowmem_type);
267err_dax_slowmem_type:
268 kfree_const(kmem_name);
269 return rc;
270}
271
272static void __exit dax_kmem_exit(void)
273{
274 dax_driver_unregister(&device_dax_kmem_driver);
275 if (!any_hotremove_failed)
276 kfree_const(kmem_name);
277 destroy_memory_type(dax_slowmem_type);
278}
279
280MODULE_AUTHOR("Intel Corporation");
281MODULE_LICENSE("GPL v2");
282module_init(dax_kmem_init);
283module_exit(dax_kmem_exit);
284MODULE_ALIAS_DAX_DEVICE(0);
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */
3#include <linux/memremap.h>
4#include <linux/pagemap.h>
5#include <linux/memory.h>
6#include <linux/module.h>
7#include <linux/device.h>
8#include <linux/pfn_t.h>
9#include <linux/slab.h>
10#include <linux/dax.h>
11#include <linux/fs.h>
12#include <linux/mm.h>
13#include <linux/mman.h>
14#include "dax-private.h"
15#include "bus.h"
16
17/* Memory resource name used for add_memory_driver_managed(). */
18static const char *kmem_name;
19/* Set if any memory will remain added when the driver will be unloaded. */
20static bool any_hotremove_failed;
21
22int dev_dax_kmem_probe(struct device *dev)
23{
24 struct dev_dax *dev_dax = to_dev_dax(dev);
25 struct resource *res = &dev_dax->region->res;
26 resource_size_t kmem_start;
27 resource_size_t kmem_size;
28 resource_size_t kmem_end;
29 struct resource *new_res;
30 const char *new_res_name;
31 int numa_node;
32 int rc;
33
34 /*
35 * Ensure good NUMA information for the persistent memory.
36 * Without this check, there is a risk that slow memory
37 * could be mixed in a node with faster memory, causing
38 * unavoidable performance issues.
39 */
40 numa_node = dev_dax->target_node;
41 if (numa_node < 0) {
42 dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",
43 res, numa_node);
44 return -EINVAL;
45 }
46
47 /* Hotplug starting at the beginning of the next block: */
48 kmem_start = ALIGN(res->start, memory_block_size_bytes());
49
50 kmem_size = resource_size(res);
51 /* Adjust the size down to compensate for moving up kmem_start: */
52 kmem_size -= kmem_start - res->start;
53 /* Align the size down to cover only complete blocks: */
54 kmem_size &= ~(memory_block_size_bytes() - 1);
55 kmem_end = kmem_start + kmem_size;
56
57 new_res_name = kstrdup(dev_name(dev), GFP_KERNEL);
58 if (!new_res_name)
59 return -ENOMEM;
60
61 /* Region is permanently reserved if hotremove fails. */
62 new_res = request_mem_region(kmem_start, kmem_size, new_res_name);
63 if (!new_res) {
64 dev_warn(dev, "could not reserve region [%pa-%pa]\n",
65 &kmem_start, &kmem_end);
66 kfree(new_res_name);
67 return -EBUSY;
68 }
69
70 /*
71 * Set flags appropriate for System RAM. Leave ..._BUSY clear
72 * so that add_memory() can add a child resource. Do not
73 * inherit flags from the parent since it may set new flags
74 * unknown to us that will break add_memory() below.
75 */
76 new_res->flags = IORESOURCE_SYSTEM_RAM;
77
78 /*
79 * Ensure that future kexec'd kernels will not treat this as RAM
80 * automatically.
81 */
82 rc = add_memory_driver_managed(numa_node, new_res->start,
83 resource_size(new_res), kmem_name);
84 if (rc) {
85 release_resource(new_res);
86 kfree(new_res);
87 kfree(new_res_name);
88 return rc;
89 }
90 dev_dax->dax_kmem_res = new_res;
91
92 return 0;
93}
94
95#ifdef CONFIG_MEMORY_HOTREMOVE
96static int dev_dax_kmem_remove(struct device *dev)
97{
98 struct dev_dax *dev_dax = to_dev_dax(dev);
99 struct resource *res = dev_dax->dax_kmem_res;
100 resource_size_t kmem_start = res->start;
101 resource_size_t kmem_size = resource_size(res);
102 const char *res_name = res->name;
103 int rc;
104
105 /*
106 * We have one shot for removing memory, if some memory blocks were not
107 * offline prior to calling this function remove_memory() will fail, and
108 * there is no way to hotremove this memory until reboot because device
109 * unbind will succeed even if we return failure.
110 */
111 rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
112 if (rc) {
113 any_hotremove_failed = true;
114 dev_err(dev,
115 "DAX region %pR cannot be hotremoved until the next reboot\n",
116 res);
117 return rc;
118 }
119
120 /* Release and free dax resources */
121 release_resource(res);
122 kfree(res);
123 kfree(res_name);
124 dev_dax->dax_kmem_res = NULL;
125
126 return 0;
127}
128#else
129static int dev_dax_kmem_remove(struct device *dev)
130{
131 /*
132 * Without hotremove purposely leak the request_mem_region() for the
133 * device-dax range and return '0' to ->remove() attempts. The removal
134 * of the device from the driver always succeeds, but the region is
135 * permanently pinned as reserved by the unreleased
136 * request_mem_region().
137 */
138 any_hotremove_failed = true;
139 return 0;
140}
141#endif /* CONFIG_MEMORY_HOTREMOVE */
142
143static struct dax_device_driver device_dax_kmem_driver = {
144 .drv = {
145 .probe = dev_dax_kmem_probe,
146 .remove = dev_dax_kmem_remove,
147 },
148};
149
150static int __init dax_kmem_init(void)
151{
152 int rc;
153
154 /* Resource name is permanently allocated if any hotremove fails. */
155 kmem_name = kstrdup_const("System RAM (kmem)", GFP_KERNEL);
156 if (!kmem_name)
157 return -ENOMEM;
158
159 rc = dax_driver_register(&device_dax_kmem_driver);
160 if (rc)
161 kfree_const(kmem_name);
162 return rc;
163}
164
165static void __exit dax_kmem_exit(void)
166{
167 dax_driver_unregister(&device_dax_kmem_driver);
168 if (!any_hotremove_failed)
169 kfree_const(kmem_name);
170}
171
172MODULE_AUTHOR("Intel Corporation");
173MODULE_LICENSE("GPL v2");
174module_init(dax_kmem_init);
175module_exit(dax_kmem_exit);
176MODULE_ALIAS_DAX_DEVICE(0);