Loading...
Note: File does not exist in v5.9.
1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 */
14
15#include <linux/fs.h>
16#include <linux/proc_fs.h>
17#include <linux/seq_file.h>
18#include <linux/rwsem.h>
19#include <linux/kprobes.h>
20#include <linux/sched.h>
21#include <linux/hardirq.h>
22#include <linux/uaccess.h>
23#include <linux/smp.h>
24#include <linux/cdev.h>
25#include <linux/compat.h>
26#include <asm/hardwall.h>
27#include <asm/traps.h>
28#include <asm/siginfo.h>
29#include <asm/irq_regs.h>
30
31#include <arch/interrupts.h>
32#include <arch/spr_def.h>
33
34
35/*
36 * This data structure tracks the rectangle data, etc., associated
37 * one-to-one with a "struct file *" from opening HARDWALL_FILE.
38 * Note that the file's private data points back to this structure.
39 */
40struct hardwall_info {
41 struct list_head list; /* "rectangles" list */
42 struct list_head task_head; /* head of tasks in this hardwall */
43 struct cpumask cpumask; /* cpus in the rectangle */
44 int ulhc_x; /* upper left hand corner x coord */
45 int ulhc_y; /* upper left hand corner y coord */
46 int width; /* rectangle width */
47 int height; /* rectangle height */
48 int id; /* integer id for this hardwall */
49 int teardown_in_progress; /* are we tearing this one down? */
50};
51
52/* Currently allocated hardwall rectangles */
53static LIST_HEAD(rectangles);
54
55/* /proc/tile/hardwall */
56static struct proc_dir_entry *hardwall_proc_dir;
57
58/* Functions to manage files in /proc/tile/hardwall. */
59static void hardwall_add_proc(struct hardwall_info *rect);
60static void hardwall_remove_proc(struct hardwall_info *rect);
61
62/*
63 * Guard changes to the hardwall data structures.
64 * This could be finer grained (e.g. one lock for the list of hardwall
65 * rectangles, then separate embedded locks for each one's list of tasks),
66 * but there are subtle correctness issues when trying to start with
67 * a task's "hardwall" pointer and lock the correct rectangle's embedded
68 * lock in the presence of a simultaneous deactivation, so it seems
69 * easier to have a single lock, given that none of these data
70 * structures are touched very frequently during normal operation.
71 */
72static DEFINE_SPINLOCK(hardwall_lock);
73
74/* Allow disabling UDN access. */
75static int udn_disabled;
76static int __init noudn(char *str)
77{
78 pr_info("User-space UDN access is disabled\n");
79 udn_disabled = 1;
80 return 0;
81}
82early_param("noudn", noudn);
83
84
85/*
86 * Low-level primitives
87 */
88
89/* Set a CPU bit if the CPU is online. */
90#define cpu_online_set(cpu, dst) do { \
91 if (cpu_online(cpu)) \
92 cpumask_set_cpu(cpu, dst); \
93} while (0)
94
95
96/* Does the given rectangle contain the given x,y coordinate? */
97static int contains(struct hardwall_info *r, int x, int y)
98{
99 return (x >= r->ulhc_x && x < r->ulhc_x + r->width) &&
100 (y >= r->ulhc_y && y < r->ulhc_y + r->height);
101}
102
103/* Compute the rectangle parameters and validate the cpumask. */
104static int setup_rectangle(struct hardwall_info *r, struct cpumask *mask)
105{
106 int x, y, cpu, ulhc, lrhc;
107
108 /* The first cpu is the ULHC, the last the LRHC. */
109 ulhc = find_first_bit(cpumask_bits(mask), nr_cpumask_bits);
110 lrhc = find_last_bit(cpumask_bits(mask), nr_cpumask_bits);
111
112 /* Compute the rectangle attributes from the cpus. */
113 r->ulhc_x = cpu_x(ulhc);
114 r->ulhc_y = cpu_y(ulhc);
115 r->width = cpu_x(lrhc) - r->ulhc_x + 1;
116 r->height = cpu_y(lrhc) - r->ulhc_y + 1;
117 cpumask_copy(&r->cpumask, mask);
118 r->id = ulhc; /* The ulhc cpu id can be the hardwall id. */
119
120 /* Width and height must be positive */
121 if (r->width <= 0 || r->height <= 0)
122 return -EINVAL;
123
124 /* Confirm that the cpumask is exactly the rectangle. */
125 for (y = 0, cpu = 0; y < smp_height; ++y)
126 for (x = 0; x < smp_width; ++x, ++cpu)
127 if (cpumask_test_cpu(cpu, mask) != contains(r, x, y))
128 return -EINVAL;
129
130 /*
131 * Note that offline cpus can't be drained when this UDN
132 * rectangle eventually closes. We used to detect this
133 * situation and print a warning, but it annoyed users and
134 * they ignored it anyway, so now we just return without a
135 * warning.
136 */
137 return 0;
138}
139
140/* Do the two given rectangles overlap on any cpu? */
141static int overlaps(struct hardwall_info *a, struct hardwall_info *b)
142{
143 return a->ulhc_x + a->width > b->ulhc_x && /* A not to the left */
144 b->ulhc_x + b->width > a->ulhc_x && /* B not to the left */
145 a->ulhc_y + a->height > b->ulhc_y && /* A not above */
146 b->ulhc_y + b->height > a->ulhc_y; /* B not above */
147}
148
149
150/*
151 * Hardware management of hardwall setup, teardown, trapping,
152 * and enabling/disabling PL0 access to the networks.
153 */
154
155/* Bit field values to mask together for writes to SPR_XDN_DIRECTION_PROTECT */
156enum direction_protect {
157 N_PROTECT = (1 << 0),
158 E_PROTECT = (1 << 1),
159 S_PROTECT = (1 << 2),
160 W_PROTECT = (1 << 3)
161};
162
163static void enable_firewall_interrupts(void)
164{
165 arch_local_irq_unmask_now(INT_UDN_FIREWALL);
166}
167
168static void disable_firewall_interrupts(void)
169{
170 arch_local_irq_mask_now(INT_UDN_FIREWALL);
171}
172
173/* Set up hardwall on this cpu based on the passed hardwall_info. */
174static void hardwall_setup_ipi_func(void *info)
175{
176 struct hardwall_info *r = info;
177 int cpu = smp_processor_id();
178 int x = cpu % smp_width;
179 int y = cpu / smp_width;
180 int bits = 0;
181 if (x == r->ulhc_x)
182 bits |= W_PROTECT;
183 if (x == r->ulhc_x + r->width - 1)
184 bits |= E_PROTECT;
185 if (y == r->ulhc_y)
186 bits |= N_PROTECT;
187 if (y == r->ulhc_y + r->height - 1)
188 bits |= S_PROTECT;
189 BUG_ON(bits == 0);
190 __insn_mtspr(SPR_UDN_DIRECTION_PROTECT, bits);
191 enable_firewall_interrupts();
192
193}
194
195/* Set up all cpus on edge of rectangle to enable/disable hardwall SPRs. */
196static void hardwall_setup(struct hardwall_info *r)
197{
198 int x, y, cpu, delta;
199 struct cpumask rect_cpus;
200
201 cpumask_clear(&rect_cpus);
202
203 /* First include the top and bottom edges */
204 cpu = r->ulhc_y * smp_width + r->ulhc_x;
205 delta = (r->height - 1) * smp_width;
206 for (x = 0; x < r->width; ++x, ++cpu) {
207 cpu_online_set(cpu, &rect_cpus);
208 cpu_online_set(cpu + delta, &rect_cpus);
209 }
210
211 /* Then the left and right edges */
212 cpu -= r->width;
213 delta = r->width - 1;
214 for (y = 0; y < r->height; ++y, cpu += smp_width) {
215 cpu_online_set(cpu, &rect_cpus);
216 cpu_online_set(cpu + delta, &rect_cpus);
217 }
218
219 /* Then tell all the cpus to set up their protection SPR */
220 on_each_cpu_mask(&rect_cpus, hardwall_setup_ipi_func, r, 1);
221}
222
223void __kprobes do_hardwall_trap(struct pt_regs* regs, int fault_num)
224{
225 struct hardwall_info *rect;
226 struct task_struct *p;
227 struct siginfo info;
228 int x, y;
229 int cpu = smp_processor_id();
230 int found_processes;
231 unsigned long flags;
232
233 struct pt_regs *old_regs = set_irq_regs(regs);
234 irq_enter();
235
236 /* This tile trapped a network access; find the rectangle. */
237 x = cpu % smp_width;
238 y = cpu / smp_width;
239 spin_lock_irqsave(&hardwall_lock, flags);
240 list_for_each_entry(rect, &rectangles, list) {
241 if (contains(rect, x, y))
242 break;
243 }
244
245 /*
246 * It shouldn't be possible not to find this cpu on the
247 * rectangle list, since only cpus in rectangles get hardwalled.
248 * The hardwall is only removed after the UDN is drained.
249 */
250 BUG_ON(&rect->list == &rectangles);
251
252 /*
253 * If we already started teardown on this hardwall, don't worry;
254 * the abort signal has been sent and we are just waiting for things
255 * to quiesce.
256 */
257 if (rect->teardown_in_progress) {
258 pr_notice("cpu %d: detected hardwall violation %#lx"
259 " while teardown already in progress\n",
260 cpu, (long) __insn_mfspr(SPR_UDN_DIRECTION_PROTECT));
261 goto done;
262 }
263
264 /*
265 * Kill off any process that is activated in this rectangle.
266 * We bypass security to deliver the signal, since it must be
267 * one of the activated processes that generated the UDN
268 * message that caused this trap, and all the activated
269 * processes shared a single open file so are pretty tightly
270 * bound together from a security point of view to begin with.
271 */
272 rect->teardown_in_progress = 1;
273 wmb(); /* Ensure visibility of rectangle before notifying processes. */
274 pr_notice("cpu %d: detected hardwall violation %#lx...\n",
275 cpu, (long) __insn_mfspr(SPR_UDN_DIRECTION_PROTECT));
276 info.si_signo = SIGILL;
277 info.si_errno = 0;
278 info.si_code = ILL_HARDWALL;
279 found_processes = 0;
280 list_for_each_entry(p, &rect->task_head, thread.hardwall_list) {
281 BUG_ON(p->thread.hardwall != rect);
282 if (!(p->flags & PF_EXITING)) {
283 found_processes = 1;
284 pr_notice("hardwall: killing %d\n", p->pid);
285 do_send_sig_info(info.si_signo, &info, p, false);
286 }
287 }
288 if (!found_processes)
289 pr_notice("hardwall: no associated processes!\n");
290
291 done:
292 spin_unlock_irqrestore(&hardwall_lock, flags);
293
294 /*
295 * We have to disable firewall interrupts now, or else when we
296 * return from this handler, we will simply re-interrupt back to
297 * it. However, we can't clear the protection bits, since we
298 * haven't yet drained the network, and that would allow packets
299 * to cross out of the hardwall region.
300 */
301 disable_firewall_interrupts();
302
303 irq_exit();
304 set_irq_regs(old_regs);
305}
306
307/* Allow access from user space to the UDN. */
308void grant_network_mpls(void)
309{
310 __insn_mtspr(SPR_MPL_UDN_ACCESS_SET_0, 1);
311 __insn_mtspr(SPR_MPL_UDN_AVAIL_SET_0, 1);
312 __insn_mtspr(SPR_MPL_UDN_COMPLETE_SET_0, 1);
313 __insn_mtspr(SPR_MPL_UDN_TIMER_SET_0, 1);
314#if !CHIP_HAS_REV1_XDN()
315 __insn_mtspr(SPR_MPL_UDN_REFILL_SET_0, 1);
316 __insn_mtspr(SPR_MPL_UDN_CA_SET_0, 1);
317#endif
318}
319
320/* Deny access from user space to the UDN. */
321void restrict_network_mpls(void)
322{
323 __insn_mtspr(SPR_MPL_UDN_ACCESS_SET_1, 1);
324 __insn_mtspr(SPR_MPL_UDN_AVAIL_SET_1, 1);
325 __insn_mtspr(SPR_MPL_UDN_COMPLETE_SET_1, 1);
326 __insn_mtspr(SPR_MPL_UDN_TIMER_SET_1, 1);
327#if !CHIP_HAS_REV1_XDN()
328 __insn_mtspr(SPR_MPL_UDN_REFILL_SET_1, 1);
329 __insn_mtspr(SPR_MPL_UDN_CA_SET_1, 1);
330#endif
331}
332
333
334/*
335 * Code to create, activate, deactivate, and destroy hardwall rectangles.
336 */
337
338/* Create a hardwall for the given rectangle */
339static struct hardwall_info *hardwall_create(
340 size_t size, const unsigned char __user *bits)
341{
342 struct hardwall_info *iter, *rect;
343 struct cpumask mask;
344 unsigned long flags;
345 int rc;
346
347 /* Reject crazy sizes out of hand, a la sys_mbind(). */
348 if (size > PAGE_SIZE)
349 return ERR_PTR(-EINVAL);
350
351 /* Copy whatever fits into a cpumask. */
352 if (copy_from_user(&mask, bits, min(sizeof(struct cpumask), size)))
353 return ERR_PTR(-EFAULT);
354
355 /*
356 * If the size was short, clear the rest of the mask;
357 * otherwise validate that the rest of the user mask was zero
358 * (we don't try hard to be efficient when validating huge masks).
359 */
360 if (size < sizeof(struct cpumask)) {
361 memset((char *)&mask + size, 0, sizeof(struct cpumask) - size);
362 } else if (size > sizeof(struct cpumask)) {
363 size_t i;
364 for (i = sizeof(struct cpumask); i < size; ++i) {
365 char c;
366 if (get_user(c, &bits[i]))
367 return ERR_PTR(-EFAULT);
368 if (c)
369 return ERR_PTR(-EINVAL);
370 }
371 }
372
373 /* Allocate a new rectangle optimistically. */
374 rect = kmalloc(sizeof(struct hardwall_info),
375 GFP_KERNEL | __GFP_ZERO);
376 if (rect == NULL)
377 return ERR_PTR(-ENOMEM);
378 INIT_LIST_HEAD(&rect->task_head);
379
380 /* Compute the rectangle size and validate that it's plausible. */
381 rc = setup_rectangle(rect, &mask);
382 if (rc != 0) {
383 kfree(rect);
384 return ERR_PTR(rc);
385 }
386
387 /* Confirm it doesn't overlap and add it to the list. */
388 spin_lock_irqsave(&hardwall_lock, flags);
389 list_for_each_entry(iter, &rectangles, list) {
390 if (overlaps(iter, rect)) {
391 spin_unlock_irqrestore(&hardwall_lock, flags);
392 kfree(rect);
393 return ERR_PTR(-EBUSY);
394 }
395 }
396 list_add_tail(&rect->list, &rectangles);
397 spin_unlock_irqrestore(&hardwall_lock, flags);
398
399 /* Set up appropriate hardwalling on all affected cpus. */
400 hardwall_setup(rect);
401
402 /* Create a /proc/tile/hardwall entry. */
403 hardwall_add_proc(rect);
404
405 return rect;
406}
407
408/* Activate a given hardwall on this cpu for this process. */
409static int hardwall_activate(struct hardwall_info *rect)
410{
411 int cpu, x, y;
412 unsigned long flags;
413 struct task_struct *p = current;
414 struct thread_struct *ts = &p->thread;
415
416 /* Require a rectangle. */
417 if (rect == NULL)
418 return -ENODATA;
419
420 /* Not allowed to activate a rectangle that is being torn down. */
421 if (rect->teardown_in_progress)
422 return -EINVAL;
423
424 /*
425 * Get our affinity; if we're not bound to this tile uniquely,
426 * we can't access the network registers.
427 */
428 if (cpumask_weight(&p->cpus_allowed) != 1)
429 return -EPERM;
430
431 /* Make sure we are bound to a cpu in this rectangle. */
432 cpu = smp_processor_id();
433 BUG_ON(cpumask_first(&p->cpus_allowed) != cpu);
434 x = cpu_x(cpu);
435 y = cpu_y(cpu);
436 if (!contains(rect, x, y))
437 return -EINVAL;
438
439 /* If we are already bound to this hardwall, it's a no-op. */
440 if (ts->hardwall) {
441 BUG_ON(ts->hardwall != rect);
442 return 0;
443 }
444
445 /* Success! This process gets to use the user networks on this cpu. */
446 ts->hardwall = rect;
447 spin_lock_irqsave(&hardwall_lock, flags);
448 list_add(&ts->hardwall_list, &rect->task_head);
449 spin_unlock_irqrestore(&hardwall_lock, flags);
450 grant_network_mpls();
451 printk(KERN_DEBUG "Pid %d (%s) activated for hardwall: cpu %d\n",
452 p->pid, p->comm, cpu);
453 return 0;
454}
455
456/*
457 * Deactivate a task's hardwall. Must hold hardwall_lock.
458 * This method may be called from free_task(), so we don't want to
459 * rely on too many fields of struct task_struct still being valid.
460 * We assume the cpus_allowed, pid, and comm fields are still valid.
461 */
462static void _hardwall_deactivate(struct task_struct *task)
463{
464 struct thread_struct *ts = &task->thread;
465
466 if (cpumask_weight(&task->cpus_allowed) != 1) {
467 pr_err("pid %d (%s) releasing networks with"
468 " an affinity mask containing %d cpus!\n",
469 task->pid, task->comm,
470 cpumask_weight(&task->cpus_allowed));
471 BUG();
472 }
473
474 BUG_ON(ts->hardwall == NULL);
475 ts->hardwall = NULL;
476 list_del(&ts->hardwall_list);
477 if (task == current)
478 restrict_network_mpls();
479}
480
481/* Deactivate a task's hardwall. */
482int hardwall_deactivate(struct task_struct *task)
483{
484 unsigned long flags;
485 int activated;
486
487 spin_lock_irqsave(&hardwall_lock, flags);
488 activated = (task->thread.hardwall != NULL);
489 if (activated)
490 _hardwall_deactivate(task);
491 spin_unlock_irqrestore(&hardwall_lock, flags);
492
493 if (!activated)
494 return -EINVAL;
495
496 printk(KERN_DEBUG "Pid %d (%s) deactivated for hardwall: cpu %d\n",
497 task->pid, task->comm, smp_processor_id());
498 return 0;
499}
500
501/* Stop a UDN switch before draining the network. */
502static void stop_udn_switch(void *ignored)
503{
504#if !CHIP_HAS_REV1_XDN()
505 /* Freeze the switch and the demux. */
506 __insn_mtspr(SPR_UDN_SP_FREEZE,
507 SPR_UDN_SP_FREEZE__SP_FRZ_MASK |
508 SPR_UDN_SP_FREEZE__DEMUX_FRZ_MASK |
509 SPR_UDN_SP_FREEZE__NON_DEST_EXT_MASK);
510#endif
511}
512
513/* Drain all the state from a stopped switch. */
514static void drain_udn_switch(void *ignored)
515{
516#if !CHIP_HAS_REV1_XDN()
517 int i;
518 int from_tile_words, ca_count;
519
520 /* Empty out the 5 switch point fifos. */
521 for (i = 0; i < 5; i++) {
522 int words, j;
523 __insn_mtspr(SPR_UDN_SP_FIFO_SEL, i);
524 words = __insn_mfspr(SPR_UDN_SP_STATE) & 0xF;
525 for (j = 0; j < words; j++)
526 (void) __insn_mfspr(SPR_UDN_SP_FIFO_DATA);
527 BUG_ON((__insn_mfspr(SPR_UDN_SP_STATE) & 0xF) != 0);
528 }
529
530 /* Dump out the 3 word fifo at top. */
531 from_tile_words = (__insn_mfspr(SPR_UDN_DEMUX_STATUS) >> 10) & 0x3;
532 for (i = 0; i < from_tile_words; i++)
533 (void) __insn_mfspr(SPR_UDN_DEMUX_WRITE_FIFO);
534
535 /* Empty out demuxes. */
536 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 0))
537 (void) __tile_udn0_receive();
538 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 1))
539 (void) __tile_udn1_receive();
540 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 2))
541 (void) __tile_udn2_receive();
542 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 3))
543 (void) __tile_udn3_receive();
544 BUG_ON((__insn_mfspr(SPR_UDN_DATA_AVAIL) & 0xF) != 0);
545
546 /* Empty out catch all. */
547 ca_count = __insn_mfspr(SPR_UDN_DEMUX_CA_COUNT);
548 for (i = 0; i < ca_count; i++)
549 (void) __insn_mfspr(SPR_UDN_CA_DATA);
550 BUG_ON(__insn_mfspr(SPR_UDN_DEMUX_CA_COUNT) != 0);
551
552 /* Clear demux logic. */
553 __insn_mtspr(SPR_UDN_DEMUX_CTL, 1);
554
555 /*
556 * Write switch state; experimentation indicates that 0xc3000
557 * is an idle switch point.
558 */
559 for (i = 0; i < 5; i++) {
560 __insn_mtspr(SPR_UDN_SP_FIFO_SEL, i);
561 __insn_mtspr(SPR_UDN_SP_STATE, 0xc3000);
562 }
563#endif
564}
565
566/* Reset random UDN state registers at boot up and during hardwall teardown. */
567void reset_network_state(void)
568{
569#if !CHIP_HAS_REV1_XDN()
570 /* Reset UDN coordinates to their standard value */
571 unsigned int cpu = smp_processor_id();
572 unsigned int x = cpu % smp_width;
573 unsigned int y = cpu / smp_width;
574#endif
575
576 if (udn_disabled)
577 return;
578
579#if !CHIP_HAS_REV1_XDN()
580 __insn_mtspr(SPR_UDN_TILE_COORD, (x << 18) | (y << 7));
581
582 /* Set demux tags to predefined values and enable them. */
583 __insn_mtspr(SPR_UDN_TAG_VALID, 0xf);
584 __insn_mtspr(SPR_UDN_TAG_0, (1 << 0));
585 __insn_mtspr(SPR_UDN_TAG_1, (1 << 1));
586 __insn_mtspr(SPR_UDN_TAG_2, (1 << 2));
587 __insn_mtspr(SPR_UDN_TAG_3, (1 << 3));
588#endif
589
590 /* Clear out other random registers so we have a clean slate. */
591 __insn_mtspr(SPR_UDN_AVAIL_EN, 0);
592 __insn_mtspr(SPR_UDN_DEADLOCK_TIMEOUT, 0);
593#if !CHIP_HAS_REV1_XDN()
594 __insn_mtspr(SPR_UDN_REFILL_EN, 0);
595 __insn_mtspr(SPR_UDN_DEMUX_QUEUE_SEL, 0);
596 __insn_mtspr(SPR_UDN_SP_FIFO_SEL, 0);
597#endif
598
599 /* Start the switch and demux. */
600#if !CHIP_HAS_REV1_XDN()
601 __insn_mtspr(SPR_UDN_SP_FREEZE, 0);
602#endif
603}
604
605/* Restart a UDN switch after draining. */
606static void restart_udn_switch(void *ignored)
607{
608 reset_network_state();
609
610 /* Disable firewall interrupts. */
611 __insn_mtspr(SPR_UDN_DIRECTION_PROTECT, 0);
612 disable_firewall_interrupts();
613}
614
615/* Build a struct cpumask containing all valid tiles in bounding rectangle. */
616static void fill_mask(struct hardwall_info *r, struct cpumask *result)
617{
618 int x, y, cpu;
619
620 cpumask_clear(result);
621
622 cpu = r->ulhc_y * smp_width + r->ulhc_x;
623 for (y = 0; y < r->height; ++y, cpu += smp_width - r->width) {
624 for (x = 0; x < r->width; ++x, ++cpu)
625 cpu_online_set(cpu, result);
626 }
627}
628
629/* Last reference to a hardwall is gone, so clear the network. */
630static void hardwall_destroy(struct hardwall_info *rect)
631{
632 struct task_struct *task;
633 unsigned long flags;
634 struct cpumask mask;
635
636 /* Make sure this file actually represents a rectangle. */
637 if (rect == NULL)
638 return;
639
640 /*
641 * Deactivate any remaining tasks. It's possible to race with
642 * some other thread that is exiting and hasn't yet called
643 * deactivate (when freeing its thread_info), so we carefully
644 * deactivate any remaining tasks before freeing the
645 * hardwall_info object itself.
646 */
647 spin_lock_irqsave(&hardwall_lock, flags);
648 list_for_each_entry(task, &rect->task_head, thread.hardwall_list)
649 _hardwall_deactivate(task);
650 spin_unlock_irqrestore(&hardwall_lock, flags);
651
652 /* Drain the UDN. */
653 printk(KERN_DEBUG "Clearing hardwall rectangle %dx%d %d,%d\n",
654 rect->width, rect->height, rect->ulhc_x, rect->ulhc_y);
655 fill_mask(rect, &mask);
656 on_each_cpu_mask(&mask, stop_udn_switch, NULL, 1);
657 on_each_cpu_mask(&mask, drain_udn_switch, NULL, 1);
658
659 /* Restart switch and disable firewall. */
660 on_each_cpu_mask(&mask, restart_udn_switch, NULL, 1);
661
662 /* Remove the /proc/tile/hardwall entry. */
663 hardwall_remove_proc(rect);
664
665 /* Now free the rectangle from the list. */
666 spin_lock_irqsave(&hardwall_lock, flags);
667 BUG_ON(!list_empty(&rect->task_head));
668 list_del(&rect->list);
669 spin_unlock_irqrestore(&hardwall_lock, flags);
670 kfree(rect);
671}
672
673
674static int hardwall_proc_show(struct seq_file *sf, void *v)
675{
676 struct hardwall_info *rect = sf->private;
677 char buf[256];
678
679 int rc = cpulist_scnprintf(buf, sizeof(buf), &rect->cpumask);
680 buf[rc++] = '\n';
681 seq_write(sf, buf, rc);
682 return 0;
683}
684
685static int hardwall_proc_open(struct inode *inode,
686 struct file *file)
687{
688 return single_open(file, hardwall_proc_show, PDE(inode)->data);
689}
690
691static const struct file_operations hardwall_proc_fops = {
692 .open = hardwall_proc_open,
693 .read = seq_read,
694 .llseek = seq_lseek,
695 .release = single_release,
696};
697
698static void hardwall_add_proc(struct hardwall_info *rect)
699{
700 char buf[64];
701 snprintf(buf, sizeof(buf), "%d", rect->id);
702 proc_create_data(buf, 0444, hardwall_proc_dir,
703 &hardwall_proc_fops, rect);
704}
705
706static void hardwall_remove_proc(struct hardwall_info *rect)
707{
708 char buf[64];
709 snprintf(buf, sizeof(buf), "%d", rect->id);
710 remove_proc_entry(buf, hardwall_proc_dir);
711}
712
713int proc_pid_hardwall(struct task_struct *task, char *buffer)
714{
715 struct hardwall_info *rect = task->thread.hardwall;
716 return rect ? sprintf(buffer, "%d\n", rect->id) : 0;
717}
718
719void proc_tile_hardwall_init(struct proc_dir_entry *root)
720{
721 if (!udn_disabled)
722 hardwall_proc_dir = proc_mkdir("hardwall", root);
723}
724
725
726/*
727 * Character device support via ioctl/close.
728 */
729
730static long hardwall_ioctl(struct file *file, unsigned int a, unsigned long b)
731{
732 struct hardwall_info *rect = file->private_data;
733
734 if (_IOC_TYPE(a) != HARDWALL_IOCTL_BASE)
735 return -EINVAL;
736
737 switch (_IOC_NR(a)) {
738 case _HARDWALL_CREATE:
739 if (udn_disabled)
740 return -ENOSYS;
741 if (rect != NULL)
742 return -EALREADY;
743 rect = hardwall_create(_IOC_SIZE(a),
744 (const unsigned char __user *)b);
745 if (IS_ERR(rect))
746 return PTR_ERR(rect);
747 file->private_data = rect;
748 return 0;
749
750 case _HARDWALL_ACTIVATE:
751 return hardwall_activate(rect);
752
753 case _HARDWALL_DEACTIVATE:
754 if (current->thread.hardwall != rect)
755 return -EINVAL;
756 return hardwall_deactivate(current);
757
758 case _HARDWALL_GET_ID:
759 return rect ? rect->id : -EINVAL;
760
761 default:
762 return -EINVAL;
763 }
764}
765
766#ifdef CONFIG_COMPAT
767static long hardwall_compat_ioctl(struct file *file,
768 unsigned int a, unsigned long b)
769{
770 /* Sign-extend the argument so it can be used as a pointer. */
771 return hardwall_ioctl(file, a, (unsigned long)compat_ptr(b));
772}
773#endif
774
775/* The user process closed the file; revoke access to user networks. */
776static int hardwall_flush(struct file *file, fl_owner_t owner)
777{
778 struct hardwall_info *rect = file->private_data;
779 struct task_struct *task, *tmp;
780 unsigned long flags;
781
782 if (rect) {
783 /*
784 * NOTE: if multiple threads are activated on this hardwall
785 * file, the other threads will continue having access to the
786 * UDN until they are context-switched out and back in again.
787 *
788 * NOTE: A NULL files pointer means the task is being torn
789 * down, so in that case we also deactivate it.
790 */
791 spin_lock_irqsave(&hardwall_lock, flags);
792 list_for_each_entry_safe(task, tmp, &rect->task_head,
793 thread.hardwall_list) {
794 if (task->files == owner || task->files == NULL)
795 _hardwall_deactivate(task);
796 }
797 spin_unlock_irqrestore(&hardwall_lock, flags);
798 }
799
800 return 0;
801}
802
803/* This hardwall is gone, so destroy it. */
804static int hardwall_release(struct inode *inode, struct file *file)
805{
806 hardwall_destroy(file->private_data);
807 return 0;
808}
809
810static const struct file_operations dev_hardwall_fops = {
811 .open = nonseekable_open,
812 .unlocked_ioctl = hardwall_ioctl,
813#ifdef CONFIG_COMPAT
814 .compat_ioctl = hardwall_compat_ioctl,
815#endif
816 .flush = hardwall_flush,
817 .release = hardwall_release,
818};
819
820static struct cdev hardwall_dev;
821
822static int __init dev_hardwall_init(void)
823{
824 int rc;
825 dev_t dev;
826
827 rc = alloc_chrdev_region(&dev, 0, 1, "hardwall");
828 if (rc < 0)
829 return rc;
830 cdev_init(&hardwall_dev, &dev_hardwall_fops);
831 rc = cdev_add(&hardwall_dev, dev, 1);
832 if (rc < 0)
833 return rc;
834
835 return 0;
836}
837late_initcall(dev_hardwall_init);