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6db71994 TT |
1 | /* |
2 | * Freescale Hypervisor Management Driver | |
3 | ||
4 | * Copyright (C) 2008-2011 Freescale Semiconductor, Inc. | |
5 | * Author: Timur Tabi <timur@freescale.com> | |
6 | * | |
7 | * This file is licensed under the terms of the GNU General Public License | |
8 | * version 2. This program is licensed "as is" without any warranty of any | |
9 | * kind, whether express or implied. | |
10 | * | |
11 | * The Freescale hypervisor management driver provides several services to | |
12 | * drivers and applications related to the Freescale hypervisor: | |
13 | * | |
14 | * 1. An ioctl interface for querying and managing partitions. | |
15 | * | |
16 | * 2. A file interface to reading incoming doorbells. | |
17 | * | |
18 | * 3. An interrupt handler for shutting down the partition upon receiving the | |
19 | * shutdown doorbell from a manager partition. | |
20 | * | |
21 | * 4. A kernel interface for receiving callbacks when a managed partition | |
22 | * shuts down. | |
23 | */ | |
24 | ||
25 | #include <linux/kernel.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/types.h> | |
29 | #include <linux/err.h> | |
30 | #include <linux/fs.h> | |
31 | #include <linux/miscdevice.h> | |
32 | #include <linux/mm.h> | |
33 | #include <linux/pagemap.h> | |
34 | #include <linux/slab.h> | |
35 | #include <linux/poll.h> | |
36 | #include <linux/of.h> | |
5af50730 | 37 | #include <linux/of_irq.h> |
6db71994 TT |
38 | #include <linux/reboot.h> |
39 | #include <linux/uaccess.h> | |
40 | #include <linux/notifier.h> | |
f1f4ee01 | 41 | #include <linux/interrupt.h> |
6db71994 TT |
42 | |
43 | #include <linux/io.h> | |
44 | #include <asm/fsl_hcalls.h> | |
45 | ||
46 | #include <linux/fsl_hypervisor.h> | |
47 | ||
48 | static BLOCKING_NOTIFIER_HEAD(failover_subscribers); | |
49 | ||
50 | /* | |
51 | * Ioctl interface for FSL_HV_IOCTL_PARTITION_RESTART | |
52 | * | |
53 | * Restart a running partition | |
54 | */ | |
55 | static long ioctl_restart(struct fsl_hv_ioctl_restart __user *p) | |
56 | { | |
57 | struct fsl_hv_ioctl_restart param; | |
58 | ||
59 | /* Get the parameters from the user */ | |
60 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_restart))) | |
61 | return -EFAULT; | |
62 | ||
63 | param.ret = fh_partition_restart(param.partition); | |
64 | ||
65 | if (copy_to_user(&p->ret, ¶m.ret, sizeof(__u32))) | |
66 | return -EFAULT; | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | /* | |
72 | * Ioctl interface for FSL_HV_IOCTL_PARTITION_STATUS | |
73 | * | |
74 | * Query the status of a partition | |
75 | */ | |
76 | static long ioctl_status(struct fsl_hv_ioctl_status __user *p) | |
77 | { | |
78 | struct fsl_hv_ioctl_status param; | |
79 | u32 status; | |
80 | ||
81 | /* Get the parameters from the user */ | |
82 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_status))) | |
83 | return -EFAULT; | |
84 | ||
85 | param.ret = fh_partition_get_status(param.partition, &status); | |
86 | if (!param.ret) | |
87 | param.status = status; | |
88 | ||
89 | if (copy_to_user(p, ¶m, sizeof(struct fsl_hv_ioctl_status))) | |
90 | return -EFAULT; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | /* | |
96 | * Ioctl interface for FSL_HV_IOCTL_PARTITION_START | |
97 | * | |
98 | * Start a stopped partition. | |
99 | */ | |
100 | static long ioctl_start(struct fsl_hv_ioctl_start __user *p) | |
101 | { | |
102 | struct fsl_hv_ioctl_start param; | |
103 | ||
104 | /* Get the parameters from the user */ | |
105 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_start))) | |
106 | return -EFAULT; | |
107 | ||
108 | param.ret = fh_partition_start(param.partition, param.entry_point, | |
109 | param.load); | |
110 | ||
111 | if (copy_to_user(&p->ret, ¶m.ret, sizeof(__u32))) | |
112 | return -EFAULT; | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | /* | |
118 | * Ioctl interface for FSL_HV_IOCTL_PARTITION_STOP | |
119 | * | |
120 | * Stop a running partition | |
121 | */ | |
122 | static long ioctl_stop(struct fsl_hv_ioctl_stop __user *p) | |
123 | { | |
124 | struct fsl_hv_ioctl_stop param; | |
125 | ||
126 | /* Get the parameters from the user */ | |
127 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_stop))) | |
128 | return -EFAULT; | |
129 | ||
130 | param.ret = fh_partition_stop(param.partition); | |
131 | ||
132 | if (copy_to_user(&p->ret, ¶m.ret, sizeof(__u32))) | |
133 | return -EFAULT; | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
138 | /* | |
139 | * Ioctl interface for FSL_HV_IOCTL_MEMCPY | |
140 | * | |
141 | * The FH_MEMCPY hypercall takes an array of address/address/size structures | |
142 | * to represent the data being copied. As a convenience to the user, this | |
143 | * ioctl takes a user-create buffer and a pointer to a guest physically | |
144 | * contiguous buffer in the remote partition, and creates the | |
145 | * address/address/size array for the hypercall. | |
146 | */ | |
147 | static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p) | |
148 | { | |
149 | struct fsl_hv_ioctl_memcpy param; | |
150 | ||
151 | struct page **pages = NULL; | |
152 | void *sg_list_unaligned = NULL; | |
153 | struct fh_sg_list *sg_list = NULL; | |
154 | ||
155 | unsigned int num_pages; | |
156 | unsigned long lb_offset; /* Offset within a page of the local buffer */ | |
157 | ||
158 | unsigned int i; | |
159 | long ret = 0; | |
160 | int num_pinned; /* return value from get_user_pages() */ | |
161 | phys_addr_t remote_paddr; /* The next address in the remote buffer */ | |
162 | uint32_t count; /* The number of bytes left to copy */ | |
163 | ||
164 | /* Get the parameters from the user */ | |
165 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_memcpy))) | |
166 | return -EFAULT; | |
167 | ||
168 | /* | |
169 | * One partition must be local, the other must be remote. In other | |
170 | * words, if source and target are both -1, or are both not -1, then | |
171 | * return an error. | |
172 | */ | |
173 | if ((param.source == -1) == (param.target == -1)) | |
174 | return -EINVAL; | |
175 | ||
176 | /* | |
177 | * The array of pages returned by get_user_pages() covers only | |
178 | * page-aligned memory. Since the user buffer is probably not | |
179 | * page-aligned, we need to handle the discrepancy. | |
180 | * | |
181 | * We calculate the offset within a page of the S/G list, and make | |
182 | * adjustments accordingly. This will result in a page list that looks | |
183 | * like this: | |
184 | * | |
185 | * ---- <-- first page starts before the buffer | |
186 | * | | | |
187 | * |////|-> ---- | |
188 | * |////| | | | |
189 | * ---- | | | |
190 | * | | | |
191 | * ---- | | | |
192 | * |////| | | | |
193 | * |////| | | | |
194 | * |////| | | | |
195 | * ---- | | | |
196 | * | | | |
197 | * ---- | | | |
198 | * |////| | | | |
199 | * |////| | | | |
200 | * |////| | | | |
201 | * ---- | | | |
202 | * | | | |
203 | * ---- | | | |
204 | * |////| | | | |
205 | * |////|-> ---- | |
206 | * | | <-- last page ends after the buffer | |
207 | * ---- | |
208 | * | |
209 | * The distance between the start of the first page and the start of the | |
210 | * buffer is lb_offset. The hashed (///) areas are the parts of the | |
211 | * page list that contain the actual buffer. | |
212 | * | |
213 | * The advantage of this approach is that the number of pages is | |
214 | * equal to the number of entries in the S/G list that we give to the | |
215 | * hypervisor. | |
216 | */ | |
217 | lb_offset = param.local_vaddr & (PAGE_SIZE - 1); | |
218 | num_pages = (param.count + lb_offset + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
219 | ||
220 | /* Allocate the buffers we need */ | |
221 | ||
222 | /* | |
223 | * 'pages' is an array of struct page pointers that's initialized by | |
224 | * get_user_pages(). | |
225 | */ | |
226 | pages = kzalloc(num_pages * sizeof(struct page *), GFP_KERNEL); | |
227 | if (!pages) { | |
228 | pr_debug("fsl-hv: could not allocate page list\n"); | |
229 | return -ENOMEM; | |
230 | } | |
231 | ||
232 | /* | |
233 | * sg_list is the list of fh_sg_list objects that we pass to the | |
234 | * hypervisor. | |
235 | */ | |
236 | sg_list_unaligned = kmalloc(num_pages * sizeof(struct fh_sg_list) + | |
237 | sizeof(struct fh_sg_list) - 1, GFP_KERNEL); | |
238 | if (!sg_list_unaligned) { | |
239 | pr_debug("fsl-hv: could not allocate S/G list\n"); | |
240 | ret = -ENOMEM; | |
241 | goto exit; | |
242 | } | |
243 | sg_list = PTR_ALIGN(sg_list_unaligned, sizeof(struct fh_sg_list)); | |
244 | ||
245 | /* Get the physical addresses of the source buffer */ | |
246 | down_read(¤t->mm->mmap_sem); | |
d4edcf0d | 247 | num_pinned = get_user_pages(param.local_vaddr - lb_offset, |
768ae309 LS |
248 | num_pages, (param.source == -1) ? 0 : FOLL_WRITE, |
249 | pages, NULL); | |
6db71994 TT |
250 | up_read(¤t->mm->mmap_sem); |
251 | ||
252 | if (num_pinned != num_pages) { | |
253 | /* get_user_pages() failed */ | |
254 | pr_debug("fsl-hv: could not lock source buffer\n"); | |
255 | ret = (num_pinned < 0) ? num_pinned : -EFAULT; | |
256 | goto exit; | |
257 | } | |
258 | ||
259 | /* | |
260 | * Build the fh_sg_list[] array. The first page is special | |
261 | * because it's misaligned. | |
262 | */ | |
263 | if (param.source == -1) { | |
264 | sg_list[0].source = page_to_phys(pages[0]) + lb_offset; | |
265 | sg_list[0].target = param.remote_paddr; | |
266 | } else { | |
267 | sg_list[0].source = param.remote_paddr; | |
268 | sg_list[0].target = page_to_phys(pages[0]) + lb_offset; | |
269 | } | |
270 | sg_list[0].size = min_t(uint64_t, param.count, PAGE_SIZE - lb_offset); | |
271 | ||
272 | remote_paddr = param.remote_paddr + sg_list[0].size; | |
273 | count = param.count - sg_list[0].size; | |
274 | ||
275 | for (i = 1; i < num_pages; i++) { | |
276 | if (param.source == -1) { | |
277 | /* local to remote */ | |
278 | sg_list[i].source = page_to_phys(pages[i]); | |
279 | sg_list[i].target = remote_paddr; | |
280 | } else { | |
281 | /* remote to local */ | |
282 | sg_list[i].source = remote_paddr; | |
283 | sg_list[i].target = page_to_phys(pages[i]); | |
284 | } | |
285 | sg_list[i].size = min_t(uint64_t, count, PAGE_SIZE); | |
286 | ||
287 | remote_paddr += sg_list[i].size; | |
288 | count -= sg_list[i].size; | |
289 | } | |
290 | ||
291 | param.ret = fh_partition_memcpy(param.source, param.target, | |
292 | virt_to_phys(sg_list), num_pages); | |
293 | ||
294 | exit: | |
295 | if (pages) { | |
296 | for (i = 0; i < num_pages; i++) | |
297 | if (pages[i]) | |
298 | put_page(pages[i]); | |
299 | } | |
300 | ||
301 | kfree(sg_list_unaligned); | |
302 | kfree(pages); | |
303 | ||
304 | if (!ret) | |
305 | if (copy_to_user(&p->ret, ¶m.ret, sizeof(__u32))) | |
306 | return -EFAULT; | |
307 | ||
308 | return ret; | |
309 | } | |
310 | ||
311 | /* | |
312 | * Ioctl interface for FSL_HV_IOCTL_DOORBELL | |
313 | * | |
314 | * Ring a doorbell | |
315 | */ | |
316 | static long ioctl_doorbell(struct fsl_hv_ioctl_doorbell __user *p) | |
317 | { | |
318 | struct fsl_hv_ioctl_doorbell param; | |
319 | ||
320 | /* Get the parameters from the user. */ | |
321 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_doorbell))) | |
322 | return -EFAULT; | |
323 | ||
324 | param.ret = ev_doorbell_send(param.doorbell); | |
325 | ||
326 | if (copy_to_user(&p->ret, ¶m.ret, sizeof(__u32))) | |
327 | return -EFAULT; | |
328 | ||
329 | return 0; | |
330 | } | |
331 | ||
332 | static long ioctl_dtprop(struct fsl_hv_ioctl_prop __user *p, int set) | |
333 | { | |
334 | struct fsl_hv_ioctl_prop param; | |
335 | char __user *upath, *upropname; | |
336 | void __user *upropval; | |
337 | char *path = NULL, *propname = NULL; | |
338 | void *propval = NULL; | |
339 | int ret = 0; | |
340 | ||
341 | /* Get the parameters from the user. */ | |
342 | if (copy_from_user(¶m, p, sizeof(struct fsl_hv_ioctl_prop))) | |
343 | return -EFAULT; | |
344 | ||
345 | upath = (char __user *)(uintptr_t)param.path; | |
346 | upropname = (char __user *)(uintptr_t)param.propname; | |
347 | upropval = (void __user *)(uintptr_t)param.propval; | |
348 | ||
349 | path = strndup_user(upath, FH_DTPROP_MAX_PATHLEN); | |
350 | if (IS_ERR(path)) { | |
351 | ret = PTR_ERR(path); | |
352 | goto out; | |
353 | } | |
354 | ||
355 | propname = strndup_user(upropname, FH_DTPROP_MAX_PATHLEN); | |
356 | if (IS_ERR(propname)) { | |
357 | ret = PTR_ERR(propname); | |
358 | goto out; | |
359 | } | |
360 | ||
361 | if (param.proplen > FH_DTPROP_MAX_PROPLEN) { | |
362 | ret = -EINVAL; | |
363 | goto out; | |
364 | } | |
365 | ||
366 | propval = kmalloc(param.proplen, GFP_KERNEL); | |
367 | if (!propval) { | |
368 | ret = -ENOMEM; | |
369 | goto out; | |
370 | } | |
371 | ||
372 | if (set) { | |
373 | if (copy_from_user(propval, upropval, param.proplen)) { | |
374 | ret = -EFAULT; | |
375 | goto out; | |
376 | } | |
377 | ||
378 | param.ret = fh_partition_set_dtprop(param.handle, | |
379 | virt_to_phys(path), | |
380 | virt_to_phys(propname), | |
381 | virt_to_phys(propval), | |
382 | param.proplen); | |
383 | } else { | |
384 | param.ret = fh_partition_get_dtprop(param.handle, | |
385 | virt_to_phys(path), | |
386 | virt_to_phys(propname), | |
387 | virt_to_phys(propval), | |
388 | ¶m.proplen); | |
389 | ||
390 | if (param.ret == 0) { | |
391 | if (copy_to_user(upropval, propval, param.proplen) || | |
392 | put_user(param.proplen, &p->proplen)) { | |
393 | ret = -EFAULT; | |
394 | goto out; | |
395 | } | |
396 | } | |
397 | } | |
398 | ||
399 | if (put_user(param.ret, &p->ret)) | |
400 | ret = -EFAULT; | |
401 | ||
402 | out: | |
403 | kfree(path); | |
404 | kfree(propval); | |
405 | kfree(propname); | |
406 | ||
407 | return ret; | |
408 | } | |
409 | ||
410 | /* | |
411 | * Ioctl main entry point | |
412 | */ | |
413 | static long fsl_hv_ioctl(struct file *file, unsigned int cmd, | |
414 | unsigned long argaddr) | |
415 | { | |
416 | void __user *arg = (void __user *)argaddr; | |
417 | long ret; | |
418 | ||
419 | switch (cmd) { | |
420 | case FSL_HV_IOCTL_PARTITION_RESTART: | |
421 | ret = ioctl_restart(arg); | |
422 | break; | |
423 | case FSL_HV_IOCTL_PARTITION_GET_STATUS: | |
424 | ret = ioctl_status(arg); | |
425 | break; | |
426 | case FSL_HV_IOCTL_PARTITION_START: | |
427 | ret = ioctl_start(arg); | |
428 | break; | |
429 | case FSL_HV_IOCTL_PARTITION_STOP: | |
430 | ret = ioctl_stop(arg); | |
431 | break; | |
432 | case FSL_HV_IOCTL_MEMCPY: | |
433 | ret = ioctl_memcpy(arg); | |
434 | break; | |
435 | case FSL_HV_IOCTL_DOORBELL: | |
436 | ret = ioctl_doorbell(arg); | |
437 | break; | |
438 | case FSL_HV_IOCTL_GETPROP: | |
439 | ret = ioctl_dtprop(arg, 0); | |
440 | break; | |
441 | case FSL_HV_IOCTL_SETPROP: | |
442 | ret = ioctl_dtprop(arg, 1); | |
443 | break; | |
444 | default: | |
445 | pr_debug("fsl-hv: bad ioctl dir=%u type=%u cmd=%u size=%u\n", | |
446 | _IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), | |
447 | _IOC_SIZE(cmd)); | |
448 | return -ENOTTY; | |
449 | } | |
450 | ||
451 | return ret; | |
452 | } | |
453 | ||
454 | /* Linked list of processes that have us open */ | |
455 | static struct list_head db_list; | |
456 | ||
457 | /* spinlock for db_list */ | |
458 | static DEFINE_SPINLOCK(db_list_lock); | |
459 | ||
460 | /* The size of the doorbell event queue. This must be a power of two. */ | |
461 | #define QSIZE 16 | |
462 | ||
463 | /* Returns the next head/tail pointer, wrapping around the queue if necessary */ | |
464 | #define nextp(x) (((x) + 1) & (QSIZE - 1)) | |
465 | ||
466 | /* Per-open data structure */ | |
467 | struct doorbell_queue { | |
468 | struct list_head list; | |
469 | spinlock_t lock; | |
470 | wait_queue_head_t wait; | |
471 | unsigned int head; | |
472 | unsigned int tail; | |
473 | uint32_t q[QSIZE]; | |
474 | }; | |
475 | ||
476 | /* Linked list of ISRs that we registered */ | |
477 | struct list_head isr_list; | |
478 | ||
479 | /* Per-ISR data structure */ | |
480 | struct doorbell_isr { | |
481 | struct list_head list; | |
482 | unsigned int irq; | |
483 | uint32_t doorbell; /* The doorbell handle */ | |
484 | uint32_t partition; /* The partition handle, if used */ | |
485 | }; | |
486 | ||
487 | /* | |
488 | * Add a doorbell to all of the doorbell queues | |
489 | */ | |
490 | static void fsl_hv_queue_doorbell(uint32_t doorbell) | |
491 | { | |
492 | struct doorbell_queue *dbq; | |
493 | unsigned long flags; | |
494 | ||
495 | /* Prevent another core from modifying db_list */ | |
496 | spin_lock_irqsave(&db_list_lock, flags); | |
497 | ||
498 | list_for_each_entry(dbq, &db_list, list) { | |
499 | if (dbq->head != nextp(dbq->tail)) { | |
500 | dbq->q[dbq->tail] = doorbell; | |
501 | /* | |
502 | * This memory barrier eliminates the need to grab | |
503 | * the spinlock for dbq. | |
504 | */ | |
505 | smp_wmb(); | |
506 | dbq->tail = nextp(dbq->tail); | |
507 | wake_up_interruptible(&dbq->wait); | |
508 | } | |
509 | } | |
510 | ||
511 | spin_unlock_irqrestore(&db_list_lock, flags); | |
512 | } | |
513 | ||
514 | /* | |
515 | * Interrupt handler for all doorbells | |
516 | * | |
517 | * We use the same interrupt handler for all doorbells. Whenever a doorbell | |
518 | * is rung, and we receive an interrupt, we just put the handle for that | |
519 | * doorbell (passed to us as *data) into all of the queues. | |
520 | */ | |
521 | static irqreturn_t fsl_hv_isr(int irq, void *data) | |
522 | { | |
523 | fsl_hv_queue_doorbell((uintptr_t) data); | |
524 | ||
525 | return IRQ_HANDLED; | |
526 | } | |
527 | ||
528 | /* | |
529 | * State change thread function | |
530 | * | |
531 | * The state change notification arrives in an interrupt, but we can't call | |
532 | * blocking_notifier_call_chain() in an interrupt handler. We could call | |
533 | * atomic_notifier_call_chain(), but that would require the clients' call-back | |
534 | * function to run in interrupt context. Since we don't want to impose that | |
535 | * restriction on the clients, we use a threaded IRQ to process the | |
536 | * notification in kernel context. | |
537 | */ | |
538 | static irqreturn_t fsl_hv_state_change_thread(int irq, void *data) | |
539 | { | |
540 | struct doorbell_isr *dbisr = data; | |
541 | ||
542 | blocking_notifier_call_chain(&failover_subscribers, dbisr->partition, | |
543 | NULL); | |
544 | ||
545 | return IRQ_HANDLED; | |
546 | } | |
547 | ||
548 | /* | |
549 | * Interrupt handler for state-change doorbells | |
550 | */ | |
551 | static irqreturn_t fsl_hv_state_change_isr(int irq, void *data) | |
552 | { | |
553 | unsigned int status; | |
554 | struct doorbell_isr *dbisr = data; | |
555 | int ret; | |
556 | ||
557 | /* It's still a doorbell, so add it to all the queues. */ | |
558 | fsl_hv_queue_doorbell(dbisr->doorbell); | |
559 | ||
560 | /* Determine the new state, and if it's stopped, notify the clients. */ | |
561 | ret = fh_partition_get_status(dbisr->partition, &status); | |
562 | if (!ret && (status == FH_PARTITION_STOPPED)) | |
563 | return IRQ_WAKE_THREAD; | |
564 | ||
565 | return IRQ_HANDLED; | |
566 | } | |
567 | ||
568 | /* | |
569 | * Returns a bitmask indicating whether a read will block | |
570 | */ | |
571 | static unsigned int fsl_hv_poll(struct file *filp, struct poll_table_struct *p) | |
572 | { | |
573 | struct doorbell_queue *dbq = filp->private_data; | |
574 | unsigned long flags; | |
575 | unsigned int mask; | |
576 | ||
577 | spin_lock_irqsave(&dbq->lock, flags); | |
578 | ||
579 | poll_wait(filp, &dbq->wait, p); | |
580 | mask = (dbq->head == dbq->tail) ? 0 : (POLLIN | POLLRDNORM); | |
581 | ||
582 | spin_unlock_irqrestore(&dbq->lock, flags); | |
583 | ||
584 | return mask; | |
585 | } | |
586 | ||
587 | /* | |
588 | * Return the handles for any incoming doorbells | |
589 | * | |
590 | * If there are doorbell handles in the queue for this open instance, then | |
591 | * return them to the caller as an array of 32-bit integers. Otherwise, | |
592 | * block until there is at least one handle to return. | |
593 | */ | |
594 | static ssize_t fsl_hv_read(struct file *filp, char __user *buf, size_t len, | |
595 | loff_t *off) | |
596 | { | |
597 | struct doorbell_queue *dbq = filp->private_data; | |
598 | uint32_t __user *p = (uint32_t __user *) buf; /* for put_user() */ | |
599 | unsigned long flags; | |
600 | ssize_t count = 0; | |
601 | ||
602 | /* Make sure we stop when the user buffer is full. */ | |
603 | while (len >= sizeof(uint32_t)) { | |
604 | uint32_t dbell; /* Local copy of doorbell queue data */ | |
605 | ||
606 | spin_lock_irqsave(&dbq->lock, flags); | |
607 | ||
608 | /* | |
609 | * If the queue is empty, then either we're done or we need | |
610 | * to block. If the application specified O_NONBLOCK, then | |
611 | * we return the appropriate error code. | |
612 | */ | |
613 | if (dbq->head == dbq->tail) { | |
614 | spin_unlock_irqrestore(&dbq->lock, flags); | |
615 | if (count) | |
616 | break; | |
617 | if (filp->f_flags & O_NONBLOCK) | |
618 | return -EAGAIN; | |
619 | if (wait_event_interruptible(dbq->wait, | |
620 | dbq->head != dbq->tail)) | |
621 | return -ERESTARTSYS; | |
622 | continue; | |
623 | } | |
624 | ||
625 | /* | |
626 | * Even though we have an smp_wmb() in the ISR, the core | |
627 | * might speculatively execute the "dbell = ..." below while | |
628 | * it's evaluating the if-statement above. In that case, the | |
629 | * value put into dbell could be stale if the core accepts the | |
630 | * speculation. To prevent that, we need a read memory barrier | |
631 | * here as well. | |
632 | */ | |
633 | smp_rmb(); | |
634 | ||
635 | /* Copy the data to a temporary local buffer, because | |
636 | * we can't call copy_to_user() from inside a spinlock | |
637 | */ | |
638 | dbell = dbq->q[dbq->head]; | |
639 | dbq->head = nextp(dbq->head); | |
640 | ||
641 | spin_unlock_irqrestore(&dbq->lock, flags); | |
642 | ||
643 | if (put_user(dbell, p)) | |
644 | return -EFAULT; | |
645 | p++; | |
646 | count += sizeof(uint32_t); | |
647 | len -= sizeof(uint32_t); | |
648 | } | |
649 | ||
650 | return count; | |
651 | } | |
652 | ||
653 | /* | |
654 | * Open the driver and prepare for reading doorbells. | |
655 | * | |
656 | * Every time an application opens the driver, we create a doorbell queue | |
657 | * for that file handle. This queue is used for any incoming doorbells. | |
658 | */ | |
659 | static int fsl_hv_open(struct inode *inode, struct file *filp) | |
660 | { | |
661 | struct doorbell_queue *dbq; | |
662 | unsigned long flags; | |
663 | int ret = 0; | |
664 | ||
665 | dbq = kzalloc(sizeof(struct doorbell_queue), GFP_KERNEL); | |
666 | if (!dbq) { | |
667 | pr_err("fsl-hv: out of memory\n"); | |
668 | return -ENOMEM; | |
669 | } | |
670 | ||
671 | spin_lock_init(&dbq->lock); | |
672 | init_waitqueue_head(&dbq->wait); | |
673 | ||
674 | spin_lock_irqsave(&db_list_lock, flags); | |
675 | list_add(&dbq->list, &db_list); | |
676 | spin_unlock_irqrestore(&db_list_lock, flags); | |
677 | ||
678 | filp->private_data = dbq; | |
679 | ||
680 | return ret; | |
681 | } | |
682 | ||
683 | /* | |
684 | * Close the driver | |
685 | */ | |
686 | static int fsl_hv_close(struct inode *inode, struct file *filp) | |
687 | { | |
688 | struct doorbell_queue *dbq = filp->private_data; | |
689 | unsigned long flags; | |
690 | ||
691 | int ret = 0; | |
692 | ||
693 | spin_lock_irqsave(&db_list_lock, flags); | |
694 | list_del(&dbq->list); | |
695 | spin_unlock_irqrestore(&db_list_lock, flags); | |
696 | ||
697 | kfree(dbq); | |
698 | ||
699 | return ret; | |
700 | } | |
701 | ||
702 | static const struct file_operations fsl_hv_fops = { | |
703 | .owner = THIS_MODULE, | |
704 | .open = fsl_hv_open, | |
705 | .release = fsl_hv_close, | |
706 | .poll = fsl_hv_poll, | |
707 | .read = fsl_hv_read, | |
708 | .unlocked_ioctl = fsl_hv_ioctl, | |
c031ab15 | 709 | .compat_ioctl = fsl_hv_ioctl, |
6db71994 TT |
710 | }; |
711 | ||
712 | static struct miscdevice fsl_hv_misc_dev = { | |
713 | MISC_DYNAMIC_MINOR, | |
714 | "fsl-hv", | |
715 | &fsl_hv_fops | |
716 | }; | |
717 | ||
718 | static irqreturn_t fsl_hv_shutdown_isr(int irq, void *data) | |
719 | { | |
720 | orderly_poweroff(false); | |
721 | ||
722 | return IRQ_HANDLED; | |
723 | } | |
724 | ||
725 | /* | |
726 | * Returns the handle of the parent of the given node | |
727 | * | |
728 | * The handle is the value of the 'hv-handle' property | |
729 | */ | |
730 | static int get_parent_handle(struct device_node *np) | |
731 | { | |
732 | struct device_node *parent; | |
733 | const uint32_t *prop; | |
734 | uint32_t handle; | |
735 | int len; | |
736 | ||
737 | parent = of_get_parent(np); | |
738 | if (!parent) | |
739 | /* It's not really possible for this to fail */ | |
740 | return -ENODEV; | |
741 | ||
742 | /* | |
743 | * The proper name for the handle property is "hv-handle", but some | |
744 | * older versions of the hypervisor used "reg". | |
745 | */ | |
746 | prop = of_get_property(parent, "hv-handle", &len); | |
747 | if (!prop) | |
748 | prop = of_get_property(parent, "reg", &len); | |
749 | ||
750 | if (!prop || (len != sizeof(uint32_t))) { | |
751 | /* This can happen only if the node is malformed */ | |
752 | of_node_put(parent); | |
753 | return -ENODEV; | |
754 | } | |
755 | ||
756 | handle = be32_to_cpup(prop); | |
757 | of_node_put(parent); | |
758 | ||
759 | return handle; | |
760 | } | |
761 | ||
762 | /* | |
763 | * Register a callback for failover events | |
764 | * | |
765 | * This function is called by device drivers to register their callback | |
766 | * functions for fail-over events. | |
767 | */ | |
768 | int fsl_hv_failover_register(struct notifier_block *nb) | |
769 | { | |
770 | return blocking_notifier_chain_register(&failover_subscribers, nb); | |
771 | } | |
772 | EXPORT_SYMBOL(fsl_hv_failover_register); | |
773 | ||
774 | /* | |
775 | * Unregister a callback for failover events | |
776 | */ | |
777 | int fsl_hv_failover_unregister(struct notifier_block *nb) | |
778 | { | |
779 | return blocking_notifier_chain_unregister(&failover_subscribers, nb); | |
780 | } | |
781 | EXPORT_SYMBOL(fsl_hv_failover_unregister); | |
782 | ||
783 | /* | |
784 | * Return TRUE if we're running under FSL hypervisor | |
785 | * | |
786 | * This function checks to see if we're running under the Freescale | |
787 | * hypervisor, and returns zero if we're not, or non-zero if we are. | |
788 | * | |
789 | * First, it checks if MSR[GS]==1, which means we're running under some | |
790 | * hypervisor. Then it checks if there is a hypervisor node in the device | |
791 | * tree. Currently, that means there needs to be a node in the root called | |
792 | * "hypervisor" and which has a property named "fsl,hv-version". | |
793 | */ | |
794 | static int has_fsl_hypervisor(void) | |
795 | { | |
796 | struct device_node *node; | |
797 | int ret; | |
798 | ||
6db71994 TT |
799 | node = of_find_node_by_path("/hypervisor"); |
800 | if (!node) | |
801 | return 0; | |
802 | ||
803 | ret = of_find_property(node, "fsl,hv-version", NULL) != NULL; | |
804 | ||
805 | of_node_put(node); | |
806 | ||
807 | return ret; | |
808 | } | |
809 | ||
810 | /* | |
811 | * Freescale hypervisor management driver init | |
812 | * | |
813 | * This function is called when this module is loaded. | |
814 | * | |
815 | * Register ourselves as a miscellaneous driver. This will register the | |
816 | * fops structure and create the right sysfs entries for udev. | |
817 | */ | |
818 | static int __init fsl_hypervisor_init(void) | |
819 | { | |
820 | struct device_node *np; | |
821 | struct doorbell_isr *dbisr, *n; | |
822 | int ret; | |
823 | ||
824 | pr_info("Freescale hypervisor management driver\n"); | |
825 | ||
826 | if (!has_fsl_hypervisor()) { | |
827 | pr_info("fsl-hv: no hypervisor found\n"); | |
828 | return -ENODEV; | |
829 | } | |
830 | ||
831 | ret = misc_register(&fsl_hv_misc_dev); | |
832 | if (ret) { | |
833 | pr_err("fsl-hv: cannot register device\n"); | |
834 | return ret; | |
835 | } | |
836 | ||
837 | INIT_LIST_HEAD(&db_list); | |
838 | INIT_LIST_HEAD(&isr_list); | |
839 | ||
840 | for_each_compatible_node(np, NULL, "epapr,hv-receive-doorbell") { | |
841 | unsigned int irq; | |
842 | const uint32_t *handle; | |
843 | ||
844 | handle = of_get_property(np, "interrupts", NULL); | |
845 | irq = irq_of_parse_and_map(np, 0); | |
846 | if (!handle || (irq == NO_IRQ)) { | |
847 | pr_err("fsl-hv: no 'interrupts' property in %s node\n", | |
848 | np->full_name); | |
849 | continue; | |
850 | } | |
851 | ||
852 | dbisr = kzalloc(sizeof(*dbisr), GFP_KERNEL); | |
853 | if (!dbisr) | |
854 | goto out_of_memory; | |
855 | ||
856 | dbisr->irq = irq; | |
857 | dbisr->doorbell = be32_to_cpup(handle); | |
858 | ||
859 | if (of_device_is_compatible(np, "fsl,hv-shutdown-doorbell")) { | |
860 | /* The shutdown doorbell gets its own ISR */ | |
861 | ret = request_irq(irq, fsl_hv_shutdown_isr, 0, | |
862 | np->name, NULL); | |
863 | } else if (of_device_is_compatible(np, | |
864 | "fsl,hv-state-change-doorbell")) { | |
865 | /* | |
866 | * The state change doorbell triggers a notification if | |
867 | * the state of the managed partition changes to | |
868 | * "stopped". We need a separate interrupt handler for | |
869 | * that, and we also need to know the handle of the | |
870 | * target partition, not just the handle of the | |
871 | * doorbell. | |
872 | */ | |
873 | dbisr->partition = ret = get_parent_handle(np); | |
874 | if (ret < 0) { | |
875 | pr_err("fsl-hv: node %s has missing or " | |
876 | "malformed parent\n", np->full_name); | |
877 | kfree(dbisr); | |
878 | continue; | |
879 | } | |
880 | ret = request_threaded_irq(irq, fsl_hv_state_change_isr, | |
881 | fsl_hv_state_change_thread, | |
882 | 0, np->name, dbisr); | |
883 | } else | |
884 | ret = request_irq(irq, fsl_hv_isr, 0, np->name, dbisr); | |
885 | ||
886 | if (ret < 0) { | |
887 | pr_err("fsl-hv: could not request irq %u for node %s\n", | |
888 | irq, np->full_name); | |
889 | kfree(dbisr); | |
890 | continue; | |
891 | } | |
892 | ||
893 | list_add(&dbisr->list, &isr_list); | |
894 | ||
895 | pr_info("fsl-hv: registered handler for doorbell %u\n", | |
896 | dbisr->doorbell); | |
897 | } | |
898 | ||
899 | return 0; | |
900 | ||
901 | out_of_memory: | |
902 | list_for_each_entry_safe(dbisr, n, &isr_list, list) { | |
903 | free_irq(dbisr->irq, dbisr); | |
904 | list_del(&dbisr->list); | |
905 | kfree(dbisr); | |
906 | } | |
907 | ||
908 | misc_deregister(&fsl_hv_misc_dev); | |
909 | ||
910 | return -ENOMEM; | |
911 | } | |
912 | ||
913 | /* | |
914 | * Freescale hypervisor management driver termination | |
915 | * | |
916 | * This function is called when this driver is unloaded. | |
917 | */ | |
918 | static void __exit fsl_hypervisor_exit(void) | |
919 | { | |
920 | struct doorbell_isr *dbisr, *n; | |
921 | ||
922 | list_for_each_entry_safe(dbisr, n, &isr_list, list) { | |
923 | free_irq(dbisr->irq, dbisr); | |
924 | list_del(&dbisr->list); | |
925 | kfree(dbisr); | |
926 | } | |
927 | ||
928 | misc_deregister(&fsl_hv_misc_dev); | |
929 | } | |
930 | ||
931 | module_init(fsl_hypervisor_init); | |
932 | module_exit(fsl_hypervisor_exit); | |
933 | ||
934 | MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); | |
935 | MODULE_DESCRIPTION("Freescale hypervisor management driver"); | |
936 | MODULE_LICENSE("GPL v2"); |