Commit | Line | Data |
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fc59a3fc JK |
1 | /* |
2 | * Virtual Processor Dispatch Trace Log | |
3 | * | |
4 | * (C) Copyright IBM Corporation 2009 | |
5 | * | |
6 | * Author: Jeremy Kerr <jk@ozlabs.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2, or (at your option) | |
11 | * any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | */ | |
22 | ||
23 | #include <linux/init.h> | |
5a0e3ad6 | 24 | #include <linux/slab.h> |
fc59a3fc | 25 | #include <linux/debugfs.h> |
872e439a | 26 | #include <linux/spinlock.h> |
fc59a3fc | 27 | #include <asm/smp.h> |
fc59a3fc | 28 | #include <asm/uaccess.h> |
b71a0c29 | 29 | #include <asm/firmware.h> |
cf9efce0 | 30 | #include <asm/lppaca.h> |
ae3a197e | 31 | #include <asm/debug.h> |
212bebb4 | 32 | #include <asm/plpar_wrappers.h> |
fc59a3fc | 33 | |
fc59a3fc JK |
34 | struct dtl { |
35 | struct dtl_entry *buf; | |
36 | struct dentry *file; | |
37 | int cpu; | |
38 | int buf_entries; | |
39 | u64 last_idx; | |
872e439a | 40 | spinlock_t lock; |
fc59a3fc | 41 | }; |
6b7487fc | 42 | static DEFINE_PER_CPU(struct dtl, cpu_dtl); |
fc59a3fc JK |
43 | |
44 | /* | |
45 | * Dispatch trace log event mask: | |
46 | * 0x7: 0x1: voluntary virtual processor waits | |
47 | * 0x2: time-slice preempts | |
48 | * 0x4: virtual partition memory page faults | |
49 | */ | |
50 | static u8 dtl_event_mask = 0x7; | |
51 | ||
52 | ||
53 | /* | |
af442a1b NA |
54 | * Size of per-cpu log buffers. Firmware requires that the buffer does |
55 | * not cross a 4k boundary. | |
fc59a3fc | 56 | */ |
af442a1b | 57 | static int dtl_buf_entries = N_DISPATCH_LOG; |
fc59a3fc | 58 | |
abf917cd | 59 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE |
872e439a PM |
60 | struct dtl_ring { |
61 | u64 write_index; | |
62 | struct dtl_entry *write_ptr; | |
63 | struct dtl_entry *buf; | |
64 | struct dtl_entry *buf_end; | |
65 | u8 saved_dtl_mask; | |
66 | }; | |
67 | ||
68 | static DEFINE_PER_CPU(struct dtl_ring, dtl_rings); | |
69 | ||
70 | static atomic_t dtl_count; | |
71 | ||
72 | /* | |
73 | * The cpu accounting code controls the DTL ring buffer, and we get | |
74 | * given entries as they are processed. | |
75 | */ | |
76 | static void consume_dtle(struct dtl_entry *dtle, u64 index) | |
fc59a3fc | 77 | { |
872e439a PM |
78 | struct dtl_ring *dtlr = &__get_cpu_var(dtl_rings); |
79 | struct dtl_entry *wp = dtlr->write_ptr; | |
80 | struct lppaca *vpa = local_paca->lppaca_ptr; | |
fc59a3fc | 81 | |
872e439a PM |
82 | if (!wp) |
83 | return; | |
fc59a3fc | 84 | |
872e439a PM |
85 | *wp = *dtle; |
86 | barrier(); | |
fc59a3fc | 87 | |
872e439a | 88 | /* check for hypervisor ring buffer overflow, ignore this entry if so */ |
7ffcf8ec | 89 | if (index + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) |
872e439a PM |
90 | return; |
91 | ||
92 | ++wp; | |
93 | if (wp == dtlr->buf_end) | |
94 | wp = dtlr->buf; | |
95 | dtlr->write_ptr = wp; | |
96 | ||
97 | /* incrementing write_index makes the new entry visible */ | |
98 | smp_wmb(); | |
99 | ++dtlr->write_index; | |
100 | } | |
101 | ||
102 | static int dtl_start(struct dtl *dtl) | |
103 | { | |
104 | struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu); | |
105 | ||
106 | dtlr->buf = dtl->buf; | |
107 | dtlr->buf_end = dtl->buf + dtl->buf_entries; | |
108 | dtlr->write_index = 0; | |
109 | ||
110 | /* setting write_ptr enables logging into our buffer */ | |
111 | smp_wmb(); | |
112 | dtlr->write_ptr = dtl->buf; | |
113 | ||
114 | /* enable event logging */ | |
115 | dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask; | |
116 | lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask; | |
117 | ||
118 | dtl_consumer = consume_dtle; | |
119 | atomic_inc(&dtl_count); | |
120 | return 0; | |
121 | } | |
122 | ||
123 | static void dtl_stop(struct dtl *dtl) | |
124 | { | |
125 | struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu); | |
126 | ||
127 | dtlr->write_ptr = NULL; | |
128 | smp_wmb(); | |
129 | ||
130 | dtlr->buf = NULL; | |
131 | ||
132 | /* restore dtl_enable_mask */ | |
133 | lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask; | |
134 | ||
135 | if (atomic_dec_and_test(&dtl_count)) | |
136 | dtl_consumer = NULL; | |
137 | } | |
138 | ||
139 | static u64 dtl_current_index(struct dtl *dtl) | |
140 | { | |
141 | return per_cpu(dtl_rings, dtl->cpu).write_index; | |
142 | } | |
143 | ||
abf917cd | 144 | #else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ |
872e439a PM |
145 | |
146 | static int dtl_start(struct dtl *dtl) | |
147 | { | |
148 | unsigned long addr; | |
149 | int ret, hwcpu; | |
fc59a3fc JK |
150 | |
151 | /* Register our dtl buffer with the hypervisor. The HV expects the | |
152 | * buffer size to be passed in the second word of the buffer */ | |
af442a1b | 153 | ((u32 *)dtl->buf)[1] = DISPATCH_LOG_BYTES; |
fc59a3fc JK |
154 | |
155 | hwcpu = get_hard_smp_processor_id(dtl->cpu); | |
156 | addr = __pa(dtl->buf); | |
157 | ret = register_dtl(hwcpu, addr); | |
158 | if (ret) { | |
159 | printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) " | |
160 | "failed with %d\n", __func__, dtl->cpu, hwcpu, ret); | |
fc59a3fc JK |
161 | return -EIO; |
162 | } | |
163 | ||
164 | /* set our initial buffer indices */ | |
872e439a | 165 | lppaca_of(dtl->cpu).dtl_idx = 0; |
fc59a3fc | 166 | |
82631f5d JK |
167 | /* ensure that our updates to the lppaca fields have occurred before |
168 | * we actually enable the logging */ | |
169 | smp_wmb(); | |
170 | ||
fc59a3fc | 171 | /* enable event logging */ |
8154c5d2 | 172 | lppaca_of(dtl->cpu).dtl_enable_mask = dtl_event_mask; |
fc59a3fc JK |
173 | |
174 | return 0; | |
175 | } | |
176 | ||
872e439a | 177 | static void dtl_stop(struct dtl *dtl) |
fc59a3fc JK |
178 | { |
179 | int hwcpu = get_hard_smp_processor_id(dtl->cpu); | |
180 | ||
8154c5d2 | 181 | lppaca_of(dtl->cpu).dtl_enable_mask = 0x0; |
fc59a3fc | 182 | |
b1301797 | 183 | unregister_dtl(hwcpu); |
872e439a PM |
184 | } |
185 | ||
186 | static u64 dtl_current_index(struct dtl *dtl) | |
187 | { | |
188 | return lppaca_of(dtl->cpu).dtl_idx; | |
189 | } | |
abf917cd | 190 | #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ |
fc59a3fc | 191 | |
872e439a PM |
192 | static int dtl_enable(struct dtl *dtl) |
193 | { | |
194 | long int n_entries; | |
195 | long int rc; | |
196 | struct dtl_entry *buf = NULL; | |
197 | ||
af442a1b NA |
198 | if (!dtl_cache) |
199 | return -ENOMEM; | |
200 | ||
872e439a PM |
201 | /* only allow one reader */ |
202 | if (dtl->buf) | |
203 | return -EBUSY; | |
204 | ||
205 | n_entries = dtl_buf_entries; | |
af442a1b | 206 | buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu)); |
872e439a PM |
207 | if (!buf) { |
208 | printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", | |
209 | __func__, dtl->cpu); | |
210 | return -ENOMEM; | |
211 | } | |
212 | ||
213 | spin_lock(&dtl->lock); | |
214 | rc = -EBUSY; | |
215 | if (!dtl->buf) { | |
216 | /* store the original allocation size for use during read */ | |
217 | dtl->buf_entries = n_entries; | |
218 | dtl->buf = buf; | |
219 | dtl->last_idx = 0; | |
220 | rc = dtl_start(dtl); | |
221 | if (rc) | |
222 | dtl->buf = NULL; | |
223 | } | |
224 | spin_unlock(&dtl->lock); | |
225 | ||
226 | if (rc) | |
af442a1b | 227 | kmem_cache_free(dtl_cache, buf); |
872e439a PM |
228 | return rc; |
229 | } | |
230 | ||
231 | static void dtl_disable(struct dtl *dtl) | |
232 | { | |
233 | spin_lock(&dtl->lock); | |
234 | dtl_stop(dtl); | |
af442a1b | 235 | kmem_cache_free(dtl_cache, dtl->buf); |
fc59a3fc JK |
236 | dtl->buf = NULL; |
237 | dtl->buf_entries = 0; | |
872e439a | 238 | spin_unlock(&dtl->lock); |
fc59a3fc JK |
239 | } |
240 | ||
241 | /* file interface */ | |
242 | ||
243 | static int dtl_file_open(struct inode *inode, struct file *filp) | |
244 | { | |
245 | struct dtl *dtl = inode->i_private; | |
246 | int rc; | |
247 | ||
248 | rc = dtl_enable(dtl); | |
249 | if (rc) | |
250 | return rc; | |
251 | ||
252 | filp->private_data = dtl; | |
253 | return 0; | |
254 | } | |
255 | ||
256 | static int dtl_file_release(struct inode *inode, struct file *filp) | |
257 | { | |
258 | struct dtl *dtl = inode->i_private; | |
259 | dtl_disable(dtl); | |
260 | return 0; | |
261 | } | |
262 | ||
263 | static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len, | |
264 | loff_t *pos) | |
265 | { | |
872e439a | 266 | long int rc, n_read, n_req, read_size; |
fc59a3fc | 267 | struct dtl *dtl; |
872e439a | 268 | u64 cur_idx, last_idx, i; |
fc59a3fc JK |
269 | |
270 | if ((len % sizeof(struct dtl_entry)) != 0) | |
271 | return -EINVAL; | |
272 | ||
273 | dtl = filp->private_data; | |
274 | ||
275 | /* requested number of entries to read */ | |
276 | n_req = len / sizeof(struct dtl_entry); | |
277 | ||
278 | /* actual number of entries read */ | |
279 | n_read = 0; | |
280 | ||
872e439a PM |
281 | spin_lock(&dtl->lock); |
282 | ||
283 | cur_idx = dtl_current_index(dtl); | |
fc59a3fc JK |
284 | last_idx = dtl->last_idx; |
285 | ||
872e439a PM |
286 | if (last_idx + dtl->buf_entries <= cur_idx) |
287 | last_idx = cur_idx - dtl->buf_entries + 1; | |
288 | ||
289 | if (last_idx + n_req > cur_idx) | |
290 | n_req = cur_idx - last_idx; | |
fc59a3fc | 291 | |
872e439a PM |
292 | if (n_req > 0) |
293 | dtl->last_idx = last_idx + n_req; | |
294 | ||
295 | spin_unlock(&dtl->lock); | |
296 | ||
297 | if (n_req <= 0) | |
298 | return 0; | |
299 | ||
300 | i = last_idx % dtl->buf_entries; | |
fc59a3fc JK |
301 | |
302 | /* read the tail of the buffer if we've wrapped */ | |
872e439a PM |
303 | if (i + n_req > dtl->buf_entries) { |
304 | read_size = dtl->buf_entries - i; | |
fc59a3fc | 305 | |
872e439a | 306 | rc = copy_to_user(buf, &dtl->buf[i], |
fc59a3fc JK |
307 | read_size * sizeof(struct dtl_entry)); |
308 | if (rc) | |
309 | return -EFAULT; | |
310 | ||
872e439a | 311 | i = 0; |
fc59a3fc JK |
312 | n_req -= read_size; |
313 | n_read += read_size; | |
314 | buf += read_size * sizeof(struct dtl_entry); | |
315 | } | |
316 | ||
317 | /* .. and now the head */ | |
872e439a | 318 | rc = copy_to_user(buf, &dtl->buf[i], n_req * sizeof(struct dtl_entry)); |
fc59a3fc JK |
319 | if (rc) |
320 | return -EFAULT; | |
321 | ||
872e439a | 322 | n_read += n_req; |
fc59a3fc JK |
323 | |
324 | return n_read * sizeof(struct dtl_entry); | |
325 | } | |
326 | ||
828c0950 | 327 | static const struct file_operations dtl_fops = { |
fc59a3fc JK |
328 | .open = dtl_file_open, |
329 | .release = dtl_file_release, | |
330 | .read = dtl_file_read, | |
331 | .llseek = no_llseek, | |
332 | }; | |
333 | ||
334 | static struct dentry *dtl_dir; | |
335 | ||
336 | static int dtl_setup_file(struct dtl *dtl) | |
337 | { | |
338 | char name[10]; | |
339 | ||
340 | sprintf(name, "cpu-%d", dtl->cpu); | |
341 | ||
342 | dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops); | |
343 | if (!dtl->file) | |
344 | return -ENOMEM; | |
345 | ||
346 | return 0; | |
347 | } | |
348 | ||
349 | static int dtl_init(void) | |
350 | { | |
351 | struct dentry *event_mask_file, *buf_entries_file; | |
352 | int rc, i; | |
353 | ||
354 | if (!firmware_has_feature(FW_FEATURE_SPLPAR)) | |
355 | return -ENODEV; | |
356 | ||
357 | /* set up common debugfs structure */ | |
358 | ||
359 | rc = -ENOMEM; | |
360 | dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root); | |
361 | if (!dtl_dir) { | |
362 | printk(KERN_WARNING "%s: can't create dtl root dir\n", | |
363 | __func__); | |
364 | goto err; | |
365 | } | |
366 | ||
367 | event_mask_file = debugfs_create_x8("dtl_event_mask", 0600, | |
368 | dtl_dir, &dtl_event_mask); | |
af442a1b | 369 | buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0400, |
fc59a3fc JK |
370 | dtl_dir, &dtl_buf_entries); |
371 | ||
372 | if (!event_mask_file || !buf_entries_file) { | |
373 | printk(KERN_WARNING "%s: can't create dtl files\n", __func__); | |
374 | goto err_remove_dir; | |
375 | } | |
376 | ||
377 | /* set up the per-cpu log structures */ | |
378 | for_each_possible_cpu(i) { | |
6b7487fc | 379 | struct dtl *dtl = &per_cpu(cpu_dtl, i); |
872e439a | 380 | spin_lock_init(&dtl->lock); |
fc59a3fc JK |
381 | dtl->cpu = i; |
382 | ||
383 | rc = dtl_setup_file(dtl); | |
384 | if (rc) | |
385 | goto err_remove_dir; | |
386 | } | |
387 | ||
388 | return 0; | |
389 | ||
390 | err_remove_dir: | |
391 | debugfs_remove_recursive(dtl_dir); | |
392 | err: | |
393 | return rc; | |
394 | } | |
395 | arch_initcall(dtl_init); |