Commit | Line | Data |
---|---|---|
b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
9f36eaed | 2 | * |
f3bc08c5 MD |
3 | * ring_buffer_backend.c |
4 | * | |
886d51a3 | 5 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 MD |
6 | */ |
7 | ||
f3bc08c5 MD |
8 | #include <linux/stddef.h> |
9 | #include <linux/module.h> | |
10 | #include <linux/string.h> | |
11 | #include <linux/bitops.h> | |
12 | #include <linux/delay.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/slab.h> | |
f3bc08c5 | 15 | #include <linux/mm.h> |
df388b78 | 16 | #include <linux/vmalloc.h> |
f3bc08c5 | 17 | |
ffcc8734 | 18 | #include <wrapper/cpu.h> |
7502f47a | 19 | #include <wrapper/mm.h> |
263b6c88 | 20 | #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_mappings() */ |
24591303 MD |
21 | #include <ringbuffer/config.h> |
22 | #include <ringbuffer/backend.h> | |
23 | #include <ringbuffer/frontend.h> | |
f3bc08c5 MD |
24 | |
25 | /** | |
26 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
27 | * @config: ring buffer instance configuration | |
28 | * @buf: the buffer struct | |
29 | * @size: total size of the buffer | |
30 | * @num_subbuf: number of subbuffers | |
31 | * @extra_reader_sb: need extra subbuffer for reader | |
32 | */ | |
33 | static | |
e20c0fec MD |
34 | int lib_ring_buffer_backend_allocate(const struct lttng_kernel_ring_buffer_config *config, |
35 | struct lttng_kernel_ring_buffer_backend *bufb, | |
f3bc08c5 MD |
36 | size_t size, size_t num_subbuf, |
37 | int extra_reader_sb) | |
38 | { | |
39 | struct channel_backend *chanb = &bufb->chan->backend; | |
40 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; | |
41 | unsigned long subbuf_size, mmap_offset = 0; | |
42 | unsigned long num_subbuf_alloc; | |
43 | struct page **pages; | |
f3bc08c5 MD |
44 | unsigned long i; |
45 | ||
46 | num_pages = size >> PAGE_SHIFT; | |
1f0ab1eb FD |
47 | |
48 | /* | |
7502f47a FD |
49 | * Verify that there is enough free pages available on the system for |
50 | * the current allocation request. | |
51 | * wrapper_check_enough_free_pages uses si_mem_available() if available | |
52 | * and returns if there should be enough free pages based on the | |
53 | * current estimate. | |
1f0ab1eb | 54 | */ |
7502f47a | 55 | if (!wrapper_check_enough_free_pages(num_pages)) |
1f0ab1eb FD |
56 | goto not_enough_pages; |
57 | ||
58 | /* | |
59 | * Set the current user thread as the first target of the OOM killer. | |
60 | * If the estimate received by si_mem_available() was off, and we do | |
61 | * end up running out of memory because of this buffer allocation, we | |
62 | * want to kill the offending app first. | |
63 | */ | |
686eb005 | 64 | set_current_oom_origin(); |
1f0ab1eb | 65 | |
f3bc08c5 MD |
66 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); |
67 | subbuf_size = chanb->subbuf_size; | |
68 | num_subbuf_alloc = num_subbuf; | |
69 | ||
70 | if (extra_reader_sb) { | |
71 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
72 | num_subbuf_alloc++; | |
73 | } | |
74 | ||
df388b78 | 75 | pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages, |
f3bc08c5 | 76 | 1 << INTERNODE_CACHE_SHIFT), |
df388b78 | 77 | cpu_to_node(max(bufb->cpu, 0))); |
f3bc08c5 MD |
78 | if (unlikely(!pages)) |
79 | goto pages_error; | |
80 | ||
48f5e0b5 | 81 | bufb->array = lttng_kvmalloc_node(ALIGN(sizeof(*bufb->array) |
f3bc08c5 MD |
82 | * num_subbuf_alloc, |
83 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
84 | GFP_KERNEL | __GFP_NOWARN, |
85 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
86 | if (unlikely(!bufb->array)) |
87 | goto array_error; | |
88 | ||
89 | for (i = 0; i < num_pages; i++) { | |
90 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
df388b78 | 91 | GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0); |
f3bc08c5 MD |
92 | if (unlikely(!pages[i])) |
93 | goto depopulate; | |
f3bc08c5 MD |
94 | } |
95 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
96 | ||
97 | /* Allocate backend pages array elements */ | |
98 | for (i = 0; i < num_subbuf_alloc; i++) { | |
99 | bufb->array[i] = | |
48f5e0b5 | 100 | lttng_kvzalloc_node(ALIGN( |
e20c0fec MD |
101 | sizeof(struct lttng_kernel_ring_buffer_backend_pages) + |
102 | sizeof(struct lttng_kernel_ring_buffer_backend_page) | |
f3bc08c5 MD |
103 | * num_pages_per_subbuf, |
104 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
105 | GFP_KERNEL | __GFP_NOWARN, |
106 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
107 | if (!bufb->array[i]) |
108 | goto free_array; | |
109 | } | |
110 | ||
111 | /* Allocate write-side subbuffer table */ | |
48f5e0b5 | 112 | bufb->buf_wsb = lttng_kvzalloc_node(ALIGN( |
e20c0fec | 113 | sizeof(struct lttng_kernel_ring_buffer_backend_subbuffer) |
f3bc08c5 MD |
114 | * num_subbuf, |
115 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
116 | GFP_KERNEL | __GFP_NOWARN, |
117 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
118 | if (unlikely(!bufb->buf_wsb)) |
119 | goto free_array; | |
120 | ||
121 | for (i = 0; i < num_subbuf; i++) | |
122 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
123 | ||
124 | /* Assign read-side subbuffer table */ | |
125 | if (extra_reader_sb) | |
126 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
127 | num_subbuf_alloc - 1); | |
128 | else | |
129 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
130 | ||
5b3cf4f9 | 131 | /* Allocate subbuffer packet counter table */ |
48f5e0b5 | 132 | bufb->buf_cnt = lttng_kvzalloc_node(ALIGN( |
e20c0fec | 133 | sizeof(struct lttng_kernel_ring_buffer_backend_counts) |
5b3cf4f9 JD |
134 | * num_subbuf, |
135 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
136 | GFP_KERNEL | __GFP_NOWARN, |
137 | cpu_to_node(max(bufb->cpu, 0))); | |
5b3cf4f9 JD |
138 | if (unlikely(!bufb->buf_cnt)) |
139 | goto free_wsb; | |
140 | ||
f3bc08c5 MD |
141 | /* Assign pages to page index */ |
142 | for (i = 0; i < num_subbuf_alloc; i++) { | |
143 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
144 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
0112cb7b MD |
145 | bufb->array[i]->p[j].virt = page_address(pages[page_idx]); |
146 | bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]); | |
f3bc08c5 MD |
147 | page_idx++; |
148 | } | |
149 | if (config->output == RING_BUFFER_MMAP) { | |
150 | bufb->array[i]->mmap_offset = mmap_offset; | |
151 | mmap_offset += subbuf_size; | |
152 | } | |
153 | } | |
154 | ||
155 | /* | |
156 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
157 | * will not fault. | |
158 | */ | |
263b6c88 | 159 | wrapper_vmalloc_sync_mappings(); |
686eb005 | 160 | clear_current_oom_origin(); |
df388b78 | 161 | vfree(pages); |
f3bc08c5 MD |
162 | return 0; |
163 | ||
5b3cf4f9 | 164 | free_wsb: |
48f5e0b5 | 165 | lttng_kvfree(bufb->buf_wsb); |
f3bc08c5 MD |
166 | free_array: |
167 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
48f5e0b5 | 168 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 MD |
169 | depopulate: |
170 | /* Free all allocated pages */ | |
171 | for (i = 0; (i < num_pages && pages[i]); i++) | |
172 | __free_page(pages[i]); | |
48f5e0b5 | 173 | lttng_kvfree(bufb->array); |
f3bc08c5 | 174 | array_error: |
df388b78 | 175 | vfree(pages); |
f3bc08c5 | 176 | pages_error: |
686eb005 | 177 | clear_current_oom_origin(); |
1f0ab1eb | 178 | not_enough_pages: |
f3bc08c5 MD |
179 | return -ENOMEM; |
180 | } | |
181 | ||
e20c0fec | 182 | int lib_ring_buffer_backend_create(struct lttng_kernel_ring_buffer_backend *bufb, |
f3bc08c5 MD |
183 | struct channel_backend *chanb, int cpu) |
184 | { | |
e20c0fec | 185 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 186 | |
860c213b | 187 | bufb->chan = container_of(chanb, struct lttng_kernel_ring_buffer_channel, backend); |
f3bc08c5 MD |
188 | bufb->cpu = cpu; |
189 | ||
190 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
191 | chanb->num_subbuf, | |
192 | chanb->extra_reader_sb); | |
193 | } | |
194 | ||
e20c0fec | 195 | void lib_ring_buffer_backend_free(struct lttng_kernel_ring_buffer_backend *bufb) |
f3bc08c5 MD |
196 | { |
197 | struct channel_backend *chanb = &bufb->chan->backend; | |
198 | unsigned long i, j, num_subbuf_alloc; | |
199 | ||
200 | num_subbuf_alloc = chanb->num_subbuf; | |
201 | if (chanb->extra_reader_sb) | |
202 | num_subbuf_alloc++; | |
203 | ||
48f5e0b5 MJ |
204 | lttng_kvfree(bufb->buf_wsb); |
205 | lttng_kvfree(bufb->buf_cnt); | |
f3bc08c5 MD |
206 | for (i = 0; i < num_subbuf_alloc; i++) { |
207 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
0112cb7b | 208 | __free_page(pfn_to_page(bufb->array[i]->p[j].pfn)); |
48f5e0b5 | 209 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 | 210 | } |
48f5e0b5 | 211 | lttng_kvfree(bufb->array); |
f3bc08c5 MD |
212 | bufb->allocated = 0; |
213 | } | |
214 | ||
e20c0fec | 215 | void lib_ring_buffer_backend_reset(struct lttng_kernel_ring_buffer_backend *bufb) |
f3bc08c5 MD |
216 | { |
217 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 218 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
219 | unsigned long num_subbuf_alloc; |
220 | unsigned int i; | |
221 | ||
222 | num_subbuf_alloc = chanb->num_subbuf; | |
223 | if (chanb->extra_reader_sb) | |
224 | num_subbuf_alloc++; | |
225 | ||
226 | for (i = 0; i < chanb->num_subbuf; i++) | |
227 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
228 | if (chanb->extra_reader_sb) | |
229 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
230 | num_subbuf_alloc - 1); | |
231 | else | |
232 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
233 | ||
234 | for (i = 0; i < num_subbuf_alloc; i++) { | |
235 | /* Don't reset mmap_offset */ | |
236 | v_set(config, &bufb->array[i]->records_commit, 0); | |
237 | v_set(config, &bufb->array[i]->records_unread, 0); | |
238 | bufb->array[i]->data_size = 0; | |
239 | /* Don't reset backend page and virt addresses */ | |
240 | } | |
241 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
242 | v_set(config, &bufb->records_read, 0); | |
243 | } | |
244 | ||
245 | /* | |
246 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
247 | * each buffer when calling channel_backend_reset. | |
248 | */ | |
249 | void channel_backend_reset(struct channel_backend *chanb) | |
250 | { | |
860c213b | 251 | struct lttng_kernel_ring_buffer_channel *chan = container_of(chanb, struct lttng_kernel_ring_buffer_channel, backend); |
e20c0fec | 252 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
253 | |
254 | /* | |
255 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
256 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
257 | * priv, notifiers, config, cpumask and name. | |
258 | */ | |
259 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
260 | } | |
261 | ||
5f4c791e | 262 | #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) |
1e367326 MD |
263 | |
264 | /* | |
265 | * No need to implement a "dead" callback to do a buffer switch here, | |
266 | * because it will happen when tracing is stopped, or will be done by | |
267 | * switch timer CPU DEAD callback. | |
268 | * We don't free buffers when CPU go away, because it would make trace | |
269 | * data vanish, which is unwanted. | |
270 | */ | |
271 | int lttng_cpuhp_rb_backend_prepare(unsigned int cpu, | |
272 | struct lttng_cpuhp_node *node) | |
273 | { | |
274 | struct channel_backend *chanb = container_of(node, | |
275 | struct channel_backend, cpuhp_prepare); | |
e20c0fec MD |
276 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
277 | struct lttng_kernel_ring_buffer *buf; | |
1e367326 MD |
278 | int ret; |
279 | ||
280 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
281 | ||
282 | buf = per_cpu_ptr(chanb->buf, cpu); | |
283 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
284 | if (ret) { | |
285 | printk(KERN_ERR | |
5a15f70c | 286 | "LTTng: ring_buffer_cpu_hp_callback: cpu %d " |
1e367326 MD |
287 | "buffer creation failed\n", cpu); |
288 | return ret; | |
289 | } | |
290 | return 0; | |
291 | } | |
292 | EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare); | |
293 | ||
5f4c791e | 294 | #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
1e367326 | 295 | |
f3bc08c5 | 296 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 | 297 | |
f3bc08c5 MD |
298 | /** |
299 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
300 | * @nb: notifier block | |
301 | * @action: hotplug action to take | |
302 | * @hcpu: CPU number | |
303 | * | |
304 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
305 | */ | |
306 | static | |
e8f071d5 | 307 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
308 | unsigned long action, |
309 | void *hcpu) | |
310 | { | |
311 | unsigned int cpu = (unsigned long)hcpu; | |
312 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
313 | cpu_hp_notifier); | |
e20c0fec MD |
314 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
315 | struct lttng_kernel_ring_buffer *buf; | |
f3bc08c5 MD |
316 | int ret; |
317 | ||
318 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
319 | ||
320 | switch (action) { | |
321 | case CPU_UP_PREPARE: | |
322 | case CPU_UP_PREPARE_FROZEN: | |
323 | buf = per_cpu_ptr(chanb->buf, cpu); | |
324 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
325 | if (ret) { | |
326 | printk(KERN_ERR | |
5a15f70c | 327 | "LTTng: ring_buffer_cpu_hp_callback: cpu %d " |
f3bc08c5 MD |
328 | "buffer creation failed\n", cpu); |
329 | return NOTIFY_BAD; | |
330 | } | |
331 | break; | |
332 | case CPU_DEAD: | |
333 | case CPU_DEAD_FROZEN: | |
334 | /* No need to do a buffer switch here, because it will happen | |
335 | * when tracing is stopped, or will be done by switch timer CPU | |
336 | * DEAD callback. */ | |
337 | break; | |
338 | } | |
339 | return NOTIFY_OK; | |
340 | } | |
1e367326 | 341 | |
f3bc08c5 MD |
342 | #endif |
343 | ||
5f4c791e | 344 | #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
1e367326 | 345 | |
f3bc08c5 MD |
346 | /** |
347 | * channel_backend_init - initialize a channel backend | |
348 | * @chanb: channel backend | |
349 | * @name: channel name | |
350 | * @config: client ring buffer configuration | |
351 | * @priv: client private data | |
352 | * @parent: dentry of parent directory, %NULL for root directory | |
353 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
354 | * @num_subbuf: number of sub-buffers (power of 2) | |
355 | * | |
356 | * Returns channel pointer if successful, %NULL otherwise. | |
357 | * | |
358 | * Creates per-cpu channel buffers using the sizes and attributes | |
359 | * specified. The created channel buffer files will be named | |
360 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
361 | * | |
362 | * Called with CPU hotplug disabled. | |
363 | */ | |
364 | int channel_backend_init(struct channel_backend *chanb, | |
365 | const char *name, | |
e20c0fec | 366 | const struct lttng_kernel_ring_buffer_config *config, |
f3bc08c5 MD |
367 | void *priv, size_t subbuf_size, size_t num_subbuf) |
368 | { | |
860c213b | 369 | struct lttng_kernel_ring_buffer_channel *chan = container_of(chanb, struct lttng_kernel_ring_buffer_channel, backend); |
f3bc08c5 MD |
370 | unsigned int i; |
371 | int ret; | |
372 | ||
373 | if (!name) | |
374 | return -EPERM; | |
375 | ||
f3bc08c5 | 376 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
377 | if (subbuf_size < PAGE_SIZE) |
378 | return -EINVAL; | |
f3bc08c5 MD |
379 | |
380 | /* | |
bbda3a00 MD |
381 | * Make sure the number of subbuffers and subbuffer size are |
382 | * power of 2 and nonzero. | |
f3bc08c5 | 383 | */ |
bbda3a00 | 384 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 385 | return -EINVAL; |
bbda3a00 | 386 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 387 | return -EINVAL; |
5140d2b3 MD |
388 | /* |
389 | * Overwrite mode buffers require at least 2 subbuffers per | |
390 | * buffer. | |
391 | */ | |
392 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
393 | return -EINVAL; | |
f3bc08c5 MD |
394 | |
395 | ret = subbuffer_id_check_index(config, num_subbuf); | |
396 | if (ret) | |
397 | return ret; | |
398 | ||
399 | chanb->priv = priv; | |
400 | chanb->buf_size = num_subbuf * subbuf_size; | |
401 | chanb->subbuf_size = subbuf_size; | |
402 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
403 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
404 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
405 | chanb->extra_reader_sb = | |
406 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
407 | chanb->num_subbuf = num_subbuf; | |
a3d0aa68 KS |
408 | #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,8,0)) |
409 | strscpy(chanb->name, name, NAME_MAX); | |
410 | #else | |
f3bc08c5 | 411 | strlcpy(chanb->name, name, NAME_MAX); |
a3d0aa68 | 412 | #endif |
5a8fd222 | 413 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
414 | |
415 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
416 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
417 | return -ENOMEM; | |
418 | } | |
419 | ||
420 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
421 | /* Allocating the buffer per-cpu structures */ | |
e20c0fec | 422 | chanb->buf = alloc_percpu(struct lttng_kernel_ring_buffer); |
f3bc08c5 MD |
423 | if (!chanb->buf) |
424 | goto free_cpumask; | |
425 | ||
5f4c791e | 426 | #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) |
1e367326 MD |
427 | chanb->cpuhp_prepare.component = LTTNG_RING_BUFFER_BACKEND; |
428 | ret = cpuhp_state_add_instance(lttng_rb_hp_prepare, | |
429 | &chanb->cpuhp_prepare.node); | |
430 | if (ret) | |
431 | goto free_bufs; | |
5f4c791e | 432 | #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
1e367326 MD |
433 | |
434 | { | |
435 | /* | |
436 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
437 | * in early initcall, it will not be notified of secondary cpus. | |
438 | * In that off case, we need to allocate for all possible cpus. | |
439 | */ | |
f3bc08c5 | 440 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 MD |
441 | /* |
442 | * buf->backend.allocated test takes care of concurrent CPU | |
443 | * hotplug. | |
444 | * Priority higher than frontend, so we create the ring buffer | |
445 | * before we start the timer. | |
446 | */ | |
447 | chanb->cpu_hp_notifier.notifier_call = | |
448 | lib_ring_buffer_cpu_hp_callback; | |
449 | chanb->cpu_hp_notifier.priority = 5; | |
450 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
451 | ||
ffcc8734 | 452 | lttng_cpus_read_lock(); |
1e367326 MD |
453 | for_each_online_cpu(i) { |
454 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
455 | chanb, i); | |
456 | if (ret) | |
457 | goto free_bufs; /* cpu hotplug locked */ | |
458 | } | |
ffcc8734 | 459 | lttng_cpus_read_unlock(); |
f3bc08c5 | 460 | #else |
1e367326 MD |
461 | for_each_possible_cpu(i) { |
462 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
463 | chanb, i); | |
464 | if (ret) | |
465 | goto free_bufs; | |
466 | } | |
f3bc08c5 | 467 | #endif |
1e367326 | 468 | } |
5f4c791e | 469 | #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
f3bc08c5 | 470 | } else { |
e20c0fec | 471 | chanb->buf = kzalloc(sizeof(struct lttng_kernel_ring_buffer), GFP_KERNEL); |
f3bc08c5 MD |
472 | if (!chanb->buf) |
473 | goto free_cpumask; | |
474 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
475 | if (ret) | |
476 | goto free_bufs; | |
477 | } | |
478 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
479 | ||
480 | return 0; | |
481 | ||
482 | free_bufs: | |
483 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
5f4c791e | 484 | #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) |
5f14d8ae MD |
485 | /* |
486 | * Teardown of lttng_rb_hp_prepare instance | |
487 | * on "add" error is handled within cpu hotplug, | |
488 | * no teardown to do from the caller. | |
489 | */ | |
5f4c791e | 490 | #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
1e367326 | 491 | #ifdef CONFIG_HOTPLUG_CPU |
ffcc8734 | 492 | lttng_cpus_read_unlock(); |
1e367326 MD |
493 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
494 | #endif | |
5f4c791e | 495 | #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
f3bc08c5 | 496 | for_each_possible_cpu(i) { |
e20c0fec | 497 | struct lttng_kernel_ring_buffer *buf = |
1e367326 | 498 | per_cpu_ptr(chanb->buf, i); |
f3bc08c5 MD |
499 | |
500 | if (!buf->backend.allocated) | |
501 | continue; | |
502 | lib_ring_buffer_free(buf); | |
503 | } | |
f3bc08c5 MD |
504 | free_percpu(chanb->buf); |
505 | } else | |
506 | kfree(chanb->buf); | |
507 | free_cpumask: | |
508 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
509 | free_cpumask_var(chanb->cpumask); | |
510 | return -ENOMEM; | |
511 | } | |
512 | ||
513 | /** | |
514 | * channel_backend_unregister_notifiers - unregister notifiers | |
515 | * @chan: the channel | |
516 | * | |
517 | * Holds CPU hotplug. | |
518 | */ | |
519 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
520 | { | |
e20c0fec | 521 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 522 | |
1e367326 | 523 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
5f4c791e | 524 | #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) |
1e367326 MD |
525 | int ret; |
526 | ||
527 | ret = cpuhp_state_remove_instance(lttng_rb_hp_prepare, | |
528 | &chanb->cpuhp_prepare.node); | |
529 | WARN_ON(ret); | |
5f4c791e | 530 | #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
f3bc08c5 | 531 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
5f4c791e | 532 | #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */ |
1e367326 | 533 | } |
f3bc08c5 MD |
534 | } |
535 | ||
536 | /** | |
537 | * channel_backend_free - destroy the channel | |
538 | * @chan: the channel | |
539 | * | |
540 | * Destroy all channel buffers and frees the channel. | |
541 | */ | |
542 | void channel_backend_free(struct channel_backend *chanb) | |
543 | { | |
e20c0fec | 544 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
545 | unsigned int i; |
546 | ||
547 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
548 | for_each_possible_cpu(i) { | |
e20c0fec | 549 | struct lttng_kernel_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); |
f3bc08c5 MD |
550 | |
551 | if (!buf->backend.allocated) | |
552 | continue; | |
553 | lib_ring_buffer_free(buf); | |
554 | } | |
555 | free_cpumask_var(chanb->cpumask); | |
556 | free_percpu(chanb->buf); | |
557 | } else { | |
e20c0fec | 558 | struct lttng_kernel_ring_buffer *buf = chanb->buf; |
f3bc08c5 MD |
559 | |
560 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
561 | lib_ring_buffer_free(buf); | |
562 | kfree(buf); | |
563 | } | |
564 | } | |
565 | ||
566 | /** | |
567 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
568 | * @bufb : buffer backend | |
569 | * @offset : offset within the buffer | |
570 | * @src : source address | |
571 | * @len : length to write | |
f3bc08c5 | 572 | */ |
e20c0fec | 573 | void _lib_ring_buffer_write(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset, |
4774817f | 574 | const void *src, size_t len) |
f3bc08c5 MD |
575 | { |
576 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 577 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
4774817f | 578 | size_t sbidx, index, bytes_left_in_page; |
e20c0fec | 579 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 MD |
580 | unsigned long sb_bindex, id; |
581 | ||
582 | do { | |
f3bc08c5 MD |
583 | sbidx = offset >> chanb->subbuf_size_order; |
584 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
585 | ||
586 | /* | |
587 | * Underlying layer should never ask for writes across | |
588 | * subbuffers. | |
589 | */ | |
590 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
591 | ||
4774817f | 592 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
f3bc08c5 MD |
593 | id = bufb->buf_wsb[sbidx].id; |
594 | sb_bindex = subbuffer_id_get_index(config, id); | |
595 | rpages = bufb->array[sb_bindex]; | |
596 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
597 | && subbuffer_id_is_noref(config, id)); | |
598 | lib_ring_buffer_do_copy(config, | |
599 | rpages->p[index].virt | |
600 | + (offset & ~PAGE_MASK), | |
4774817f MD |
601 | src, bytes_left_in_page); |
602 | len -= bytes_left_in_page; | |
603 | src += bytes_left_in_page; | |
604 | offset += bytes_left_in_page; | |
605 | } while (unlikely(len)); | |
f3bc08c5 MD |
606 | } |
607 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
608 | ||
4ea00e4f JD |
609 | /** |
610 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
611 | * @bufb : buffer backend | |
612 | * @offset : offset within the buffer | |
613 | * @c : the byte to write | |
614 | * @len : length to write | |
4ea00e4f | 615 | */ |
e20c0fec | 616 | void _lib_ring_buffer_memset(struct lttng_kernel_ring_buffer_backend *bufb, |
4774817f | 617 | size_t offset, int c, size_t len) |
4ea00e4f JD |
618 | { |
619 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 620 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
4774817f | 621 | size_t sbidx, index, bytes_left_in_page; |
e20c0fec | 622 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
4ea00e4f JD |
623 | unsigned long sb_bindex, id; |
624 | ||
625 | do { | |
4ea00e4f JD |
626 | sbidx = offset >> chanb->subbuf_size_order; |
627 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
628 | ||
629 | /* | |
630 | * Underlying layer should never ask for writes across | |
631 | * subbuffers. | |
632 | */ | |
633 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
634 | ||
4774817f | 635 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
4ea00e4f JD |
636 | id = bufb->buf_wsb[sbidx].id; |
637 | sb_bindex = subbuffer_id_get_index(config, id); | |
638 | rpages = bufb->array[sb_bindex]; | |
639 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
640 | && subbuffer_id_is_noref(config, id)); | |
641 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
642 | + (offset & ~PAGE_MASK), | |
4774817f MD |
643 | c, bytes_left_in_page); |
644 | len -= bytes_left_in_page; | |
645 | offset += bytes_left_in_page; | |
646 | } while (unlikely(len)); | |
4ea00e4f JD |
647 | } |
648 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
649 | ||
16f78f3a MD |
650 | /** |
651 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
652 | * @bufb : buffer backend | |
653 | * @offset : offset within the buffer | |
654 | * @src : source address | |
655 | * @len : length to write | |
16f78f3a MD |
656 | * @pad : character to use for padding |
657 | */ | |
e20c0fec | 658 | void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, |
e5f1eb9a | 659 | size_t offset, const char *src, size_t len, int pad) |
16f78f3a MD |
660 | { |
661 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 662 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
e5f1eb9a | 663 | size_t sbidx, index, bytes_left_in_page; |
e20c0fec | 664 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
16f78f3a | 665 | unsigned long sb_bindex, id; |
e5f1eb9a | 666 | bool src_terminated = false; |
16f78f3a MD |
667 | |
668 | CHAN_WARN_ON(chanb, !len); | |
16f78f3a | 669 | do { |
16f78f3a MD |
670 | sbidx = offset >> chanb->subbuf_size_order; |
671 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
672 | ||
673 | /* | |
674 | * Underlying layer should never ask for writes across | |
675 | * subbuffers. | |
676 | */ | |
677 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
678 | ||
e5f1eb9a | 679 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
16f78f3a MD |
680 | id = bufb->buf_wsb[sbidx].id; |
681 | sb_bindex = subbuffer_id_get_index(config, id); | |
682 | rpages = bufb->array[sb_bindex]; | |
683 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
684 | && subbuffer_id_is_noref(config, id)); | |
685 | ||
686 | if (likely(!src_terminated)) { | |
687 | size_t count, to_copy; | |
688 | ||
e5f1eb9a MD |
689 | to_copy = bytes_left_in_page; |
690 | if (bytes_left_in_page == len) | |
16f78f3a MD |
691 | to_copy--; /* Final '\0' */ |
692 | count = lib_ring_buffer_do_strcpy(config, | |
693 | rpages->p[index].virt | |
694 | + (offset & ~PAGE_MASK), | |
695 | src, to_copy); | |
696 | offset += count; | |
697 | /* Padding */ | |
698 | if (unlikely(count < to_copy)) { | |
699 | size_t pad_len = to_copy - count; | |
700 | ||
701 | /* Next pages will have padding */ | |
e5f1eb9a | 702 | src_terminated = true; |
16f78f3a MD |
703 | lib_ring_buffer_do_memset(rpages->p[index].virt |
704 | + (offset & ~PAGE_MASK), | |
705 | pad, pad_len); | |
706 | offset += pad_len; | |
707 | } | |
708 | } else { | |
709 | size_t pad_len; | |
710 | ||
e5f1eb9a MD |
711 | pad_len = bytes_left_in_page; |
712 | if (bytes_left_in_page == len) | |
16f78f3a MD |
713 | pad_len--; /* Final '\0' */ |
714 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
715 | + (offset & ~PAGE_MASK), | |
716 | pad, pad_len); | |
717 | offset += pad_len; | |
718 | } | |
e5f1eb9a MD |
719 | len -= bytes_left_in_page; |
720 | if (!src_terminated) | |
721 | src += bytes_left_in_page; | |
722 | } while (unlikely(len)); | |
723 | ||
16f78f3a MD |
724 | /* Ending '\0' */ |
725 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
726 | '\0', 1); | |
727 | } | |
728 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f | 729 | |
0d1080f4 MD |
730 | /** |
731 | * _lib_ring_buffer_pstrcpy - write to a buffer backend P-string | |
732 | * @bufb : buffer backend | |
733 | * @src : source pointer to copy from | |
734 | * @len : length of data to copy | |
735 | * @pad : character to use for padding | |
736 | * | |
737 | * This function copies up to @len bytes of data from a source pointer | |
738 | * to a Pascal String into the buffer backend. If a terminating '\0' | |
739 | * character is found in @src before @len characters are copied, pad the | |
740 | * buffer with @pad characters (e.g. '\0'). | |
741 | * | |
742 | * The length of the pascal strings in the ring buffer is explicit: it | |
743 | * is either the array or sequence length. | |
744 | */ | |
745 | void _lib_ring_buffer_pstrcpy(struct lttng_kernel_ring_buffer_backend *bufb, | |
746 | size_t offset, const char *src, size_t len, int pad) | |
747 | { | |
748 | struct channel_backend *chanb = &bufb->chan->backend; | |
749 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; | |
750 | size_t sbidx, index, bytes_left_in_page; | |
751 | struct lttng_kernel_ring_buffer_backend_pages *rpages; | |
752 | unsigned long sb_bindex, id; | |
753 | bool src_terminated = false; | |
754 | ||
755 | CHAN_WARN_ON(chanb, !len); | |
756 | do { | |
757 | sbidx = offset >> chanb->subbuf_size_order; | |
758 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
759 | ||
760 | /* | |
761 | * Underlying layer should never ask for writes across | |
762 | * subbuffers. | |
763 | */ | |
764 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
765 | ||
766 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
767 | id = bufb->buf_wsb[sbidx].id; | |
768 | sb_bindex = subbuffer_id_get_index(config, id); | |
769 | rpages = bufb->array[sb_bindex]; | |
770 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
771 | && subbuffer_id_is_noref(config, id)); | |
772 | ||
773 | if (likely(!src_terminated)) { | |
774 | size_t count, to_copy; | |
775 | ||
776 | to_copy = bytes_left_in_page; | |
777 | count = lib_ring_buffer_do_strcpy(config, | |
778 | rpages->p[index].virt | |
779 | + (offset & ~PAGE_MASK), | |
780 | src, to_copy); | |
781 | offset += count; | |
782 | /* Padding */ | |
783 | if (unlikely(count < to_copy)) { | |
784 | size_t pad_len = to_copy - count; | |
785 | ||
786 | /* Next pages will have padding */ | |
787 | src_terminated = true; | |
788 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
789 | + (offset & ~PAGE_MASK), | |
790 | pad, pad_len); | |
791 | offset += pad_len; | |
792 | } | |
793 | } else { | |
794 | size_t pad_len; | |
795 | ||
796 | pad_len = bytes_left_in_page; | |
797 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
798 | + (offset & ~PAGE_MASK), | |
799 | pad, pad_len); | |
800 | offset += pad_len; | |
801 | } | |
802 | len -= bytes_left_in_page; | |
803 | if (!src_terminated) | |
804 | src += bytes_left_in_page; | |
805 | } while (unlikely(len)); | |
806 | } | |
807 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_pstrcpy); | |
808 | ||
4ea00e4f | 809 | /** |
7b8ea3a5 | 810 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
811 | * @bufb : buffer backend |
812 | * @offset : offset within the buffer | |
813 | * @src : source address | |
814 | * @len : length to write | |
4ea00e4f JD |
815 | * |
816 | * This function deals with userspace pointers, it should never be called | |
817 | * directly without having the src pointer checked with access_ok() | |
818 | * previously. | |
819 | */ | |
e20c0fec | 820 | void _lib_ring_buffer_copy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, |
4774817f | 821 | size_t offset, const void __user *src, size_t len) |
4ea00e4f JD |
822 | { |
823 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 824 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
4774817f | 825 | size_t sbidx, index, bytes_left_in_page; |
e20c0fec | 826 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
4ea00e4f JD |
827 | unsigned long sb_bindex, id; |
828 | int ret; | |
829 | ||
830 | do { | |
4ea00e4f JD |
831 | sbidx = offset >> chanb->subbuf_size_order; |
832 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
833 | ||
834 | /* | |
835 | * Underlying layer should never ask for writes across | |
836 | * subbuffers. | |
837 | */ | |
838 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
839 | ||
4774817f | 840 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
4ea00e4f JD |
841 | id = bufb->buf_wsb[sbidx].id; |
842 | sb_bindex = subbuffer_id_get_index(config, id); | |
843 | rpages = bufb->array[sb_bindex]; | |
844 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
845 | && subbuffer_id_is_noref(config, id)); | |
7b8ea3a5 | 846 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f | 847 | + (offset & ~PAGE_MASK), |
4774817f | 848 | src, bytes_left_in_page) != 0; |
4ea00e4f | 849 | if (ret > 0) { |
d87a9f03 | 850 | /* Copy failed. */ |
4774817f | 851 | _lib_ring_buffer_memset(bufb, offset, 0, len); |
4ea00e4f JD |
852 | break; /* stop copy */ |
853 | } | |
4774817f MD |
854 | len -= bytes_left_in_page; |
855 | src += bytes_left_in_page; | |
856 | offset += bytes_left_in_page; | |
857 | } while (unlikely(len)); | |
4ea00e4f | 858 | } |
7b8ea3a5 | 859 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 860 | |
16f78f3a MD |
861 | /** |
862 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
863 | * @bufb : buffer backend | |
864 | * @offset : offset within the buffer | |
865 | * @src : source address | |
866 | * @len : length to write | |
16f78f3a MD |
867 | * @pad : character to use for padding |
868 | * | |
869 | * This function deals with userspace pointers, it should never be called | |
870 | * directly without having the src pointer checked with access_ok() | |
871 | * previously. | |
872 | */ | |
e20c0fec | 873 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, |
e5f1eb9a | 874 | size_t offset, const char __user *src, size_t len, int pad) |
16f78f3a MD |
875 | { |
876 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 877 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
e5f1eb9a | 878 | size_t sbidx, index, bytes_left_in_page; |
e20c0fec | 879 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
16f78f3a | 880 | unsigned long sb_bindex, id; |
e5f1eb9a | 881 | bool src_terminated = false; |
16f78f3a | 882 | |
16f78f3a | 883 | do { |
16f78f3a MD |
884 | sbidx = offset >> chanb->subbuf_size_order; |
885 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
886 | ||
887 | /* | |
888 | * Underlying layer should never ask for writes across | |
889 | * subbuffers. | |
890 | */ | |
891 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
892 | ||
e5f1eb9a | 893 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
16f78f3a MD |
894 | id = bufb->buf_wsb[sbidx].id; |
895 | sb_bindex = subbuffer_id_get_index(config, id); | |
896 | rpages = bufb->array[sb_bindex]; | |
897 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
898 | && subbuffer_id_is_noref(config, id)); | |
899 | ||
900 | if (likely(!src_terminated)) { | |
901 | size_t count, to_copy; | |
902 | ||
e5f1eb9a MD |
903 | to_copy = bytes_left_in_page; |
904 | if (bytes_left_in_page == len) | |
16f78f3a MD |
905 | to_copy--; /* Final '\0' */ |
906 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
907 | rpages->p[index].virt | |
908 | + (offset & ~PAGE_MASK), | |
909 | src, to_copy); | |
910 | offset += count; | |
911 | /* Padding */ | |
912 | if (unlikely(count < to_copy)) { | |
913 | size_t pad_len = to_copy - count; | |
914 | ||
915 | /* Next pages will have padding */ | |
e5f1eb9a | 916 | src_terminated = true; |
16f78f3a MD |
917 | lib_ring_buffer_do_memset(rpages->p[index].virt |
918 | + (offset & ~PAGE_MASK), | |
919 | pad, pad_len); | |
920 | offset += pad_len; | |
921 | } | |
922 | } else { | |
923 | size_t pad_len; | |
924 | ||
e5f1eb9a MD |
925 | pad_len = bytes_left_in_page; |
926 | if (bytes_left_in_page == len) | |
16f78f3a MD |
927 | pad_len--; /* Final '\0' */ |
928 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
929 | + (offset & ~PAGE_MASK), | |
930 | pad, pad_len); | |
931 | offset += pad_len; | |
932 | } | |
e5f1eb9a MD |
933 | len -= bytes_left_in_page; |
934 | if (!src_terminated) | |
935 | src += bytes_left_in_page; | |
936 | } while (unlikely(len)); | |
937 | ||
16f78f3a MD |
938 | /* Ending '\0' */ |
939 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
940 | '\0', 1); | |
941 | } | |
942 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
943 | ||
0d1080f4 MD |
944 | /** |
945 | * _lib_ring_buffer_pstrcpy_from_user_inatomic - write userspace string to a buffer backend P-string | |
946 | * @bufb : buffer backend | |
947 | * @src : source pointer to copy from | |
948 | * @len : length of data to copy | |
949 | * @pad : character to use for padding | |
950 | * | |
951 | * This function copies up to @len bytes of data from a source pointer | |
952 | * to a Pascal String into the buffer backend. If a terminating '\0' | |
953 | * character is found in @src before @len characters are copied, pad the | |
954 | * buffer with @pad characters (e.g. '\0'). | |
955 | * | |
956 | * The length of the pascal strings in the ring buffer is explicit: it | |
957 | * is either the array or sequence length. | |
958 | * | |
959 | * This function deals with userspace pointers, it should never be called | |
960 | * directly without having the src pointer checked with access_ok() | |
961 | * previously. | |
962 | */ | |
963 | void _lib_ring_buffer_pstrcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, | |
964 | size_t offset, const char __user *src, size_t len, int pad) | |
965 | { | |
966 | struct channel_backend *chanb = &bufb->chan->backend; | |
967 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; | |
968 | size_t sbidx, index, bytes_left_in_page; | |
969 | struct lttng_kernel_ring_buffer_backend_pages *rpages; | |
970 | unsigned long sb_bindex, id; | |
971 | bool src_terminated = false; | |
972 | ||
973 | CHAN_WARN_ON(chanb, !len); | |
974 | do { | |
975 | sbidx = offset >> chanb->subbuf_size_order; | |
976 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
977 | ||
978 | /* | |
979 | * Underlying layer should never ask for writes across | |
980 | * subbuffers. | |
981 | */ | |
982 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
983 | ||
984 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
985 | id = bufb->buf_wsb[sbidx].id; | |
986 | sb_bindex = subbuffer_id_get_index(config, id); | |
987 | rpages = bufb->array[sb_bindex]; | |
988 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
989 | && subbuffer_id_is_noref(config, id)); | |
990 | ||
991 | if (likely(!src_terminated)) { | |
992 | size_t count, to_copy; | |
993 | ||
994 | to_copy = bytes_left_in_page; | |
995 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
996 | rpages->p[index].virt | |
997 | + (offset & ~PAGE_MASK), | |
998 | src, to_copy); | |
999 | offset += count; | |
1000 | /* Padding */ | |
1001 | if (unlikely(count < to_copy)) { | |
1002 | size_t pad_len = to_copy - count; | |
1003 | ||
1004 | /* Next pages will have padding */ | |
1005 | src_terminated = true; | |
1006 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
1007 | + (offset & ~PAGE_MASK), | |
1008 | pad, pad_len); | |
1009 | offset += pad_len; | |
1010 | } | |
1011 | } else { | |
1012 | size_t pad_len; | |
1013 | ||
1014 | pad_len = bytes_left_in_page; | |
1015 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
1016 | + (offset & ~PAGE_MASK), | |
1017 | pad, pad_len); | |
1018 | offset += pad_len; | |
1019 | } | |
1020 | len -= bytes_left_in_page; | |
1021 | if (!src_terminated) | |
1022 | src += bytes_left_in_page; | |
1023 | } while (unlikely(len)); | |
1024 | } | |
1025 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_pstrcpy_from_user_inatomic); | |
1026 | ||
f3bc08c5 MD |
1027 | /** |
1028 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
1029 | * @bufb : buffer backend | |
1030 | * @offset : offset within the buffer | |
1031 | * @dest : destination address | |
1032 | * @len : length to copy to destination | |
1033 | * | |
1034 | * Should be protected by get_subbuf/put_subbuf. | |
1035 | * Returns the length copied. | |
1036 | */ | |
e20c0fec | 1037 | size_t lib_ring_buffer_read(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset, |
f3bc08c5 MD |
1038 | void *dest, size_t len) |
1039 | { | |
1040 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 1041 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
4774817f | 1042 | size_t index, bytes_left_in_page, orig_len; |
e20c0fec | 1043 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 MD |
1044 | unsigned long sb_bindex, id; |
1045 | ||
1046 | orig_len = len; | |
1047 | offset &= chanb->buf_size - 1; | |
1048 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1049 | if (unlikely(!len)) | |
1050 | return 0; | |
1051 | for (;;) { | |
4774817f | 1052 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
f3bc08c5 MD |
1053 | id = bufb->buf_rsb.id; |
1054 | sb_bindex = subbuffer_id_get_index(config, id); | |
1055 | rpages = bufb->array[sb_bindex]; | |
1056 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1057 | && subbuffer_id_is_noref(config, id)); | |
1058 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
4774817f MD |
1059 | bytes_left_in_page); |
1060 | len -= bytes_left_in_page; | |
f3bc08c5 MD |
1061 | if (likely(!len)) |
1062 | break; | |
4774817f MD |
1063 | dest += bytes_left_in_page; |
1064 | offset += bytes_left_in_page; | |
f3bc08c5 MD |
1065 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
1066 | /* | |
1067 | * Underlying layer should never ask for reads across | |
1068 | * subbuffers. | |
1069 | */ | |
1070 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
1071 | } | |
1072 | return orig_len; | |
1073 | } | |
1074 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
1075 | ||
1076 | /** | |
1077 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
1078 | * @bufb : buffer backend | |
1079 | * @offset : offset within the buffer | |
1080 | * @dest : destination userspace address | |
1081 | * @len : length to copy to destination | |
1082 | * | |
1083 | * Should be protected by get_subbuf/put_subbuf. | |
1084 | * access_ok() must have been performed on dest addresses prior to call this | |
1085 | * function. | |
1086 | * Returns -EFAULT on error, 0 if ok. | |
1087 | */ | |
e20c0fec | 1088 | int __lib_ring_buffer_copy_to_user(struct lttng_kernel_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1089 | size_t offset, void __user *dest, size_t len) |
1090 | { | |
1091 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 1092 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 1093 | size_t index; |
4774817f | 1094 | ssize_t bytes_left_in_page; |
e20c0fec | 1095 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 MD |
1096 | unsigned long sb_bindex, id; |
1097 | ||
f3bc08c5 MD |
1098 | offset &= chanb->buf_size - 1; |
1099 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1100 | if (unlikely(!len)) | |
1101 | return 0; | |
1102 | for (;;) { | |
4774817f | 1103 | bytes_left_in_page = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
f3bc08c5 MD |
1104 | id = bufb->buf_rsb.id; |
1105 | sb_bindex = subbuffer_id_get_index(config, id); | |
1106 | rpages = bufb->array[sb_bindex]; | |
1107 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1108 | && subbuffer_id_is_noref(config, id)); | |
1109 | if (__copy_to_user(dest, | |
1110 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
4774817f | 1111 | bytes_left_in_page)) |
f3bc08c5 | 1112 | return -EFAULT; |
4774817f | 1113 | len -= bytes_left_in_page; |
f3bc08c5 MD |
1114 | if (likely(!len)) |
1115 | break; | |
4774817f MD |
1116 | dest += bytes_left_in_page; |
1117 | offset += bytes_left_in_page; | |
f3bc08c5 MD |
1118 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
1119 | /* | |
1120 | * Underlying layer should never ask for reads across | |
1121 | * subbuffers. | |
1122 | */ | |
1123 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
1124 | } | |
1125 | return 0; | |
1126 | } | |
1127 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
1128 | ||
1129 | /** | |
1130 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
1131 | * @bufb : buffer backend | |
1132 | * @offset : offset within the buffer | |
1133 | * @dest : destination address | |
1134 | * @len : destination's length | |
1135 | * | |
61eb4c39 | 1136 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 1137 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 1138 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 | 1139 | */ |
e20c0fec | 1140 | int lib_ring_buffer_read_cstr(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset, |
f3bc08c5 MD |
1141 | void *dest, size_t len) |
1142 | { | |
1143 | struct channel_backend *chanb = &bufb->chan->backend; | |
e20c0fec | 1144 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 1145 | size_t index; |
4774817f | 1146 | ssize_t bytes_left_in_page, pagelen, strpagelen, orig_offset; |
f3bc08c5 | 1147 | char *str; |
e20c0fec | 1148 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 MD |
1149 | unsigned long sb_bindex, id; |
1150 | ||
1151 | offset &= chanb->buf_size - 1; | |
1152 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1153 | orig_offset = offset; | |
61eb4c39 MD |
1154 | if (unlikely(!len)) |
1155 | return -EINVAL; | |
f3bc08c5 MD |
1156 | for (;;) { |
1157 | id = bufb->buf_rsb.id; | |
1158 | sb_bindex = subbuffer_id_get_index(config, id); | |
1159 | rpages = bufb->array[sb_bindex]; | |
1160 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1161 | && subbuffer_id_is_noref(config, id)); | |
1162 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1163 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
1164 | strpagelen = strnlen(str, pagelen); | |
1165 | if (len) { | |
4774817f | 1166 | bytes_left_in_page = min_t(size_t, len, strpagelen); |
f3bc08c5 | 1167 | if (dest) { |
4774817f MD |
1168 | memcpy(dest, str, bytes_left_in_page); |
1169 | dest += bytes_left_in_page; | |
f3bc08c5 | 1170 | } |
4774817f | 1171 | len -= bytes_left_in_page; |
f3bc08c5 MD |
1172 | } |
1173 | offset += strpagelen; | |
1174 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1175 | if (strpagelen < pagelen) | |
1176 | break; | |
1177 | /* | |
1178 | * Underlying layer should never ask for reads across | |
1179 | * subbuffers. | |
1180 | */ | |
1181 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
1182 | } | |
1183 | if (dest && len) | |
1184 | ((char *)dest)[0] = 0; | |
1185 | return offset - orig_offset; | |
1186 | } | |
1187 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
1188 | ||
1189 | /** | |
0112cb7b | 1190 | * lib_ring_buffer_read_get_pfn - Get a page frame number to read from |
f3bc08c5 MD |
1191 | * @bufb : buffer backend |
1192 | * @offset : offset within the buffer | |
1193 | * @virt : pointer to page address (output) | |
1194 | * | |
1195 | * Should be protected by get_subbuf/put_subbuf. | |
0112cb7b | 1196 | * Returns the pointer to the page frame number unsigned long. |
f3bc08c5 | 1197 | */ |
e20c0fec | 1198 | unsigned long *lib_ring_buffer_read_get_pfn(struct lttng_kernel_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1199 | size_t offset, void ***virt) |
1200 | { | |
1201 | size_t index; | |
e20c0fec | 1202 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 | 1203 | struct channel_backend *chanb = &bufb->chan->backend; |
e20c0fec | 1204 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1205 | unsigned long sb_bindex, id; |
1206 | ||
1207 | offset &= chanb->buf_size - 1; | |
1208 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1209 | id = bufb->buf_rsb.id; | |
1210 | sb_bindex = subbuffer_id_get_index(config, id); | |
1211 | rpages = bufb->array[sb_bindex]; | |
1212 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1213 | && subbuffer_id_is_noref(config, id)); | |
1214 | *virt = &rpages->p[index].virt; | |
0112cb7b | 1215 | return &rpages->p[index].pfn; |
f3bc08c5 | 1216 | } |
0112cb7b | 1217 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn); |
f3bc08c5 MD |
1218 | |
1219 | /** | |
1220 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
1221 | * @bufb : buffer backend | |
1222 | * @offset : offset within the buffer. | |
1223 | * | |
1224 | * Return the address where a given offset is located (for read). | |
1225 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
1226 | * it's never on a page boundary, it's safe to read/write directly |
1227 | * from/to this address, as long as the read/write is never bigger than a | |
1228 | * page size. | |
f3bc08c5 | 1229 | */ |
e20c0fec | 1230 | void *lib_ring_buffer_read_offset_address(struct lttng_kernel_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1231 | size_t offset) |
1232 | { | |
1233 | size_t index; | |
e20c0fec | 1234 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 | 1235 | struct channel_backend *chanb = &bufb->chan->backend; |
e20c0fec | 1236 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1237 | unsigned long sb_bindex, id; |
1238 | ||
1239 | offset &= chanb->buf_size - 1; | |
1240 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1241 | id = bufb->buf_rsb.id; | |
1242 | sb_bindex = subbuffer_id_get_index(config, id); | |
1243 | rpages = bufb->array[sb_bindex]; | |
1244 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1245 | && subbuffer_id_is_noref(config, id)); | |
1246 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1247 | } | |
1248 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1249 | ||
1250 | /** | |
1251 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1252 | * @bufb : buffer backend | |
1253 | * @offset : offset within the buffer. | |
1254 | * | |
1255 | * Return the address where a given offset is located. | |
1256 | * Should be used to get the current subbuffer header pointer. Given we know | |
1257 | * it's always at the beginning of a page, it's safe to write directly to this | |
1258 | * address, as long as the write is never bigger than a page size. | |
1259 | */ | |
e20c0fec | 1260 | void *lib_ring_buffer_offset_address(struct lttng_kernel_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1261 | size_t offset) |
1262 | { | |
1263 | size_t sbidx, index; | |
e20c0fec | 1264 | struct lttng_kernel_ring_buffer_backend_pages *rpages; |
f3bc08c5 | 1265 | struct channel_backend *chanb = &bufb->chan->backend; |
e20c0fec | 1266 | const struct lttng_kernel_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1267 | unsigned long sb_bindex, id; |
1268 | ||
1269 | offset &= chanb->buf_size - 1; | |
1270 | sbidx = offset >> chanb->subbuf_size_order; | |
1271 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1272 | id = bufb->buf_wsb[sbidx].id; | |
1273 | sb_bindex = subbuffer_id_get_index(config, id); | |
1274 | rpages = bufb->array[sb_bindex]; | |
1275 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1276 | && subbuffer_id_is_noref(config, id)); | |
1277 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1278 | } | |
1279 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |