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6
7#define pr_fmt(fmt) "memtrace: " fmt
8
9#include <linux/bitops.h>
10#include <linux/string.h>
11#include <linux/memblock.h>
12#include <linux/init.h>
13#include <linux/moduleparam.h>
14#include <linux/fs.h>
15#include <linux/debugfs.h>
16#include <linux/slab.h>
17#include <linux/memory.h>
18#include <linux/memory_hotplug.h>
19#include <linux/numa.h>
20#include <asm/machdep.h>
21#include <asm/debugfs.h>
22
23
24struct memtrace_entry {
25 void *mem;
26 u64 start;
27 u64 size;
28 u32 nid;
29 struct dentry *dir;
30 char name[16];
31};
32
33static u64 memtrace_size;
34
35static struct memtrace_entry *memtrace_array;
36static unsigned int memtrace_array_nr;
37
38
39static ssize_t memtrace_read(struct file *filp, char __user *ubuf,
40 size_t count, loff_t *ppos)
41{
42 struct memtrace_entry *ent = filp->private_data;
43
44 return simple_read_from_buffer(ubuf, count, ppos, ent->mem, ent->size);
45}
46
47static const struct file_operations memtrace_fops = {
48 .llseek = default_llseek,
49 .read = memtrace_read,
50 .open = simple_open,
51};
52
53static int check_memblock_online(struct memory_block *mem, void *arg)
54{
55 if (mem->state != MEM_ONLINE)
56 return -1;
57
58 return 0;
59}
60
61static int change_memblock_state(struct memory_block *mem, void *arg)
62{
63 unsigned long state = (unsigned long)arg;
64
65 mem->state = state;
66
67 return 0;
68}
69
70
71static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
72{
73 const unsigned long start = PFN_PHYS(start_pfn);
74 const unsigned long size = PFN_PHYS(nr_pages);
75
76 if (walk_memory_blocks(start, size, NULL, check_memblock_online))
77 return false;
78
79 walk_memory_blocks(start, size, (void *)MEM_GOING_OFFLINE,
80 change_memblock_state);
81
82 if (offline_pages(start_pfn, nr_pages)) {
83 walk_memory_blocks(start, size, (void *)MEM_ONLINE,
84 change_memblock_state);
85 return false;
86 }
87
88 walk_memory_blocks(start, size, (void *)MEM_OFFLINE,
89 change_memblock_state);
90
91
92 return true;
93}
94
95static u64 memtrace_alloc_node(u32 nid, u64 size)
96{
97 u64 start_pfn, end_pfn, nr_pages, pfn;
98 u64 base_pfn;
99 u64 bytes = memory_block_size_bytes();
100
101 if (!node_spanned_pages(nid))
102 return 0;
103
104 start_pfn = node_start_pfn(nid);
105 end_pfn = node_end_pfn(nid);
106 nr_pages = size >> PAGE_SHIFT;
107
108
109 end_pfn = round_down(end_pfn - nr_pages, nr_pages);
110
111 lock_device_hotplug();
112 for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) {
113 if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) {
114
115
116
117
118
119
120 end_pfn = base_pfn + nr_pages;
121 for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) {
122 __remove_memory(nid, pfn << PAGE_SHIFT, bytes);
123 }
124 unlock_device_hotplug();
125 return base_pfn << PAGE_SHIFT;
126 }
127 }
128 unlock_device_hotplug();
129
130 return 0;
131}
132
133static int memtrace_init_regions_runtime(u64 size)
134{
135 u32 nid;
136 u64 m;
137
138 memtrace_array = kcalloc(num_online_nodes(),
139 sizeof(struct memtrace_entry), GFP_KERNEL);
140 if (!memtrace_array) {
141 pr_err("Failed to allocate memtrace_array\n");
142 return -EINVAL;
143 }
144
145 for_each_online_node(nid) {
146 m = memtrace_alloc_node(nid, size);
147
148
149
150
151
152 if (!m) {
153 pr_err("Failed to allocate trace memory on node %d\n", nid);
154 continue;
155 }
156
157 pr_info("Allocated trace memory on node %d at 0x%016llx\n", nid, m);
158
159 memtrace_array[memtrace_array_nr].start = m;
160 memtrace_array[memtrace_array_nr].size = size;
161 memtrace_array[memtrace_array_nr].nid = nid;
162 memtrace_array_nr++;
163 }
164
165 return 0;
166}
167
168static struct dentry *memtrace_debugfs_dir;
169
170static int memtrace_init_debugfs(void)
171{
172 int ret = 0;
173 int i;
174
175 for (i = 0; i < memtrace_array_nr; i++) {
176 struct dentry *dir;
177 struct memtrace_entry *ent = &memtrace_array[i];
178
179 ent->mem = ioremap(ent->start, ent->size);
180
181 if (!ent->mem) {
182 pr_err("Failed to map trace memory at 0x%llx\n",
183 ent->start);
184 ret = -1;
185 continue;
186 }
187
188 snprintf(ent->name, 16, "%08x", ent->nid);
189 dir = debugfs_create_dir(ent->name, memtrace_debugfs_dir);
190
191 ent->dir = dir;
192 debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops);
193 debugfs_create_x64("start", 0400, dir, &ent->start);
194 debugfs_create_x64("size", 0400, dir, &ent->size);
195 }
196
197 return ret;
198}
199
200static int online_mem_block(struct memory_block *mem, void *arg)
201{
202 return device_online(&mem->dev);
203}
204
205
206
207
208
209static int memtrace_online(void)
210{
211 int i, ret = 0;
212 struct memtrace_entry *ent;
213
214 for (i = memtrace_array_nr - 1; i >= 0; i--) {
215 ent = &memtrace_array[i];
216
217
218 if (ent->nid == NUMA_NO_NODE)
219 continue;
220
221
222 if (ent->mem) {
223 iounmap(ent->mem);
224 ent->mem = 0;
225 }
226
227 if (add_memory(ent->nid, ent->start, ent->size)) {
228 pr_err("Failed to add trace memory to node %d\n",
229 ent->nid);
230 ret += 1;
231 continue;
232 }
233
234 lock_device_hotplug();
235 walk_memory_blocks(ent->start, ent->size, NULL,
236 online_mem_block);
237 unlock_device_hotplug();
238
239
240
241
242
243 debugfs_remove_recursive(ent->dir);
244 pr_info("Added trace memory back to node %d\n", ent->nid);
245 ent->size = ent->start = ent->nid = NUMA_NO_NODE;
246 }
247 if (ret)
248 return ret;
249
250
251 kfree(memtrace_array);
252 memtrace_array = NULL;
253 memtrace_size = 0;
254 memtrace_array_nr = 0;
255 return 0;
256}
257
258static int memtrace_enable_set(void *data, u64 val)
259{
260 u64 bytes;
261
262
263
264
265
266 bytes = memory_block_size_bytes();
267 if (val & (bytes - 1)) {
268 pr_err("Value must be aligned with 0x%llx\n", bytes);
269 return -EINVAL;
270 }
271
272
273 if (memtrace_size) {
274 if (memtrace_online())
275 return -EAGAIN;
276 }
277
278 if (!val)
279 return 0;
280
281
282 if (memtrace_init_regions_runtime(val))
283 return -EINVAL;
284
285 if (memtrace_init_debugfs())
286 return -EINVAL;
287
288 memtrace_size = val;
289
290 return 0;
291}
292
293static int memtrace_enable_get(void *data, u64 *val)
294{
295 *val = memtrace_size;
296 return 0;
297}
298
299DEFINE_SIMPLE_ATTRIBUTE(memtrace_init_fops, memtrace_enable_get,
300 memtrace_enable_set, "0x%016llx\n");
301
302static int memtrace_init(void)
303{
304 memtrace_debugfs_dir = debugfs_create_dir("memtrace",
305 powerpc_debugfs_root);
306
307 debugfs_create_file("enable", 0600, memtrace_debugfs_dir,
308 NULL, &memtrace_init_fops);
309
310 return 0;
311}
312machine_device_initcall(powernv, memtrace_init);
313