2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
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.
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
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>
31 #include <arch/interrupts.h>
32 #include <arch/spr_def.h>
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.
40 struct hardwall_info {
41 struct list_head list; /* "rectangles" list */
42 struct list_head task_head; /* head of tasks in this hardwall */
43 int ulhc_x; /* upper left hand corner x coord */
44 int ulhc_y; /* upper left hand corner y coord */
45 int width; /* rectangle width */
46 int height; /* rectangle height */
47 int teardown_in_progress; /* are we tearing this one down? */
50 /* Currently allocated hardwall rectangles */
51 static LIST_HEAD(rectangles);
54 * Guard changes to the hardwall data structures.
55 * This could be finer grained (e.g. one lock for the list of hardwall
56 * rectangles, then separate embedded locks for each one's list of tasks),
57 * but there are subtle correctness issues when trying to start with
58 * a task's "hardwall" pointer and lock the correct rectangle's embedded
59 * lock in the presence of a simultaneous deactivation, so it seems
60 * easier to have a single lock, given that none of these data
61 * structures are touched very frequently during normal operation.
63 static DEFINE_SPINLOCK(hardwall_lock);
65 /* Allow disabling UDN access. */
66 static int udn_disabled;
67 static int __init noudn(char *str)
69 pr_info("User-space UDN access is disabled\n");
73 early_param("noudn", noudn);
77 * Low-level primitives
80 /* Set a CPU bit if the CPU is online. */
81 #define cpu_online_set(cpu, dst) do { \
82 if (cpu_online(cpu)) \
83 cpumask_set_cpu(cpu, dst); \
87 /* Does the given rectangle contain the given x,y coordinate? */
88 static int contains(struct hardwall_info *r, int x, int y)
90 return (x >= r->ulhc_x && x < r->ulhc_x + r->width) &&
91 (y >= r->ulhc_y && y < r->ulhc_y + r->height);
94 /* Compute the rectangle parameters and validate the cpumask. */
95 static int setup_rectangle(struct hardwall_info *r, struct cpumask *mask)
97 int x, y, cpu, ulhc, lrhc;
99 /* The first cpu is the ULHC, the last the LRHC. */
100 ulhc = find_first_bit(cpumask_bits(mask), nr_cpumask_bits);
101 lrhc = find_last_bit(cpumask_bits(mask), nr_cpumask_bits);
103 /* Compute the rectangle attributes from the cpus. */
104 r->ulhc_x = cpu_x(ulhc);
105 r->ulhc_y = cpu_y(ulhc);
106 r->width = cpu_x(lrhc) - r->ulhc_x + 1;
107 r->height = cpu_y(lrhc) - r->ulhc_y + 1;
109 /* Width and height must be positive */
110 if (r->width <= 0 || r->height <= 0)
113 /* Confirm that the cpumask is exactly the rectangle. */
114 for (y = 0, cpu = 0; y < smp_height; ++y)
115 for (x = 0; x < smp_width; ++x, ++cpu)
116 if (cpumask_test_cpu(cpu, mask) != contains(r, x, y))
120 * Note that offline cpus can't be drained when this UDN
121 * rectangle eventually closes. We used to detect this
122 * situation and print a warning, but it annoyed users and
123 * they ignored it anyway, so now we just return without a
129 /* Do the two given rectangles overlap on any cpu? */
130 static int overlaps(struct hardwall_info *a, struct hardwall_info *b)
132 return a->ulhc_x + a->width > b->ulhc_x && /* A not to the left */
133 b->ulhc_x + b->width > a->ulhc_x && /* B not to the left */
134 a->ulhc_y + a->height > b->ulhc_y && /* A not above */
135 b->ulhc_y + b->height > a->ulhc_y; /* B not above */
140 * Hardware management of hardwall setup, teardown, trapping,
141 * and enabling/disabling PL0 access to the networks.
144 /* Bit field values to mask together for writes to SPR_XDN_DIRECTION_PROTECT */
145 enum direction_protect {
146 N_PROTECT = (1 << 0),
147 E_PROTECT = (1 << 1),
148 S_PROTECT = (1 << 2),
152 static void enable_firewall_interrupts(void)
154 arch_local_irq_unmask_now(INT_UDN_FIREWALL);
157 static void disable_firewall_interrupts(void)
159 arch_local_irq_mask_now(INT_UDN_FIREWALL);
162 /* Set up hardwall on this cpu based on the passed hardwall_info. */
163 static void hardwall_setup_ipi_func(void *info)
165 struct hardwall_info *r = info;
166 int cpu = smp_processor_id();
167 int x = cpu % smp_width;
168 int y = cpu / smp_width;
172 if (x == r->ulhc_x + r->width - 1)
176 if (y == r->ulhc_y + r->height - 1)
179 __insn_mtspr(SPR_UDN_DIRECTION_PROTECT, bits);
180 enable_firewall_interrupts();
184 /* Set up all cpus on edge of rectangle to enable/disable hardwall SPRs. */
185 static void hardwall_setup(struct hardwall_info *r)
187 int x, y, cpu, delta;
188 struct cpumask rect_cpus;
190 cpumask_clear(&rect_cpus);
192 /* First include the top and bottom edges */
193 cpu = r->ulhc_y * smp_width + r->ulhc_x;
194 delta = (r->height - 1) * smp_width;
195 for (x = 0; x < r->width; ++x, ++cpu) {
196 cpu_online_set(cpu, &rect_cpus);
197 cpu_online_set(cpu + delta, &rect_cpus);
200 /* Then the left and right edges */
202 delta = r->width - 1;
203 for (y = 0; y < r->height; ++y, cpu += smp_width) {
204 cpu_online_set(cpu, &rect_cpus);
205 cpu_online_set(cpu + delta, &rect_cpus);
208 /* Then tell all the cpus to set up their protection SPR */
209 on_each_cpu_mask(&rect_cpus, hardwall_setup_ipi_func, r, 1);
212 void __kprobes do_hardwall_trap(struct pt_regs* regs, int fault_num)
214 struct hardwall_info *rect;
215 struct task_struct *p;
218 int cpu = smp_processor_id();
222 struct pt_regs *old_regs = set_irq_regs(regs);
225 /* This tile trapped a network access; find the rectangle. */
228 spin_lock_irqsave(&hardwall_lock, flags);
229 list_for_each_entry(rect, &rectangles, list) {
230 if (contains(rect, x, y))
235 * It shouldn't be possible not to find this cpu on the
236 * rectangle list, since only cpus in rectangles get hardwalled.
237 * The hardwall is only removed after the UDN is drained.
239 BUG_ON(&rect->list == &rectangles);
242 * If we already started teardown on this hardwall, don't worry;
243 * the abort signal has been sent and we are just waiting for things
246 if (rect->teardown_in_progress) {
247 pr_notice("cpu %d: detected hardwall violation %#lx"
248 " while teardown already in progress\n",
249 cpu, (long) __insn_mfspr(SPR_UDN_DIRECTION_PROTECT));
254 * Kill off any process that is activated in this rectangle.
255 * We bypass security to deliver the signal, since it must be
256 * one of the activated processes that generated the UDN
257 * message that caused this trap, and all the activated
258 * processes shared a single open file so are pretty tightly
259 * bound together from a security point of view to begin with.
261 rect->teardown_in_progress = 1;
262 wmb(); /* Ensure visibility of rectangle before notifying processes. */
263 pr_notice("cpu %d: detected hardwall violation %#lx...\n",
264 cpu, (long) __insn_mfspr(SPR_UDN_DIRECTION_PROTECT));
265 info.si_signo = SIGILL;
267 info.si_code = ILL_HARDWALL;
269 list_for_each_entry(p, &rect->task_head, thread.hardwall_list) {
270 BUG_ON(p->thread.hardwall != rect);
271 if (!(p->flags & PF_EXITING)) {
273 pr_notice("hardwall: killing %d\n", p->pid);
274 do_send_sig_info(info.si_signo, &info, p, false);
277 if (!found_processes)
278 pr_notice("hardwall: no associated processes!\n");
281 spin_unlock_irqrestore(&hardwall_lock, flags);
284 * We have to disable firewall interrupts now, or else when we
285 * return from this handler, we will simply re-interrupt back to
286 * it. However, we can't clear the protection bits, since we
287 * haven't yet drained the network, and that would allow packets
288 * to cross out of the hardwall region.
290 disable_firewall_interrupts();
293 set_irq_regs(old_regs);
296 /* Allow access from user space to the UDN. */
297 void grant_network_mpls(void)
299 __insn_mtspr(SPR_MPL_UDN_ACCESS_SET_0, 1);
300 __insn_mtspr(SPR_MPL_UDN_AVAIL_SET_0, 1);
301 __insn_mtspr(SPR_MPL_UDN_COMPLETE_SET_0, 1);
302 __insn_mtspr(SPR_MPL_UDN_TIMER_SET_0, 1);
303 #if !CHIP_HAS_REV1_XDN()
304 __insn_mtspr(SPR_MPL_UDN_REFILL_SET_0, 1);
305 __insn_mtspr(SPR_MPL_UDN_CA_SET_0, 1);
309 /* Deny access from user space to the UDN. */
310 void restrict_network_mpls(void)
312 __insn_mtspr(SPR_MPL_UDN_ACCESS_SET_1, 1);
313 __insn_mtspr(SPR_MPL_UDN_AVAIL_SET_1, 1);
314 __insn_mtspr(SPR_MPL_UDN_COMPLETE_SET_1, 1);
315 __insn_mtspr(SPR_MPL_UDN_TIMER_SET_1, 1);
316 #if !CHIP_HAS_REV1_XDN()
317 __insn_mtspr(SPR_MPL_UDN_REFILL_SET_1, 1);
318 __insn_mtspr(SPR_MPL_UDN_CA_SET_1, 1);
324 * Code to create, activate, deactivate, and destroy hardwall rectangles.
327 /* Create a hardwall for the given rectangle */
328 static struct hardwall_info *hardwall_create(
329 size_t size, const unsigned char __user *bits)
331 struct hardwall_info *iter, *rect;
336 /* Reject crazy sizes out of hand, a la sys_mbind(). */
337 if (size > PAGE_SIZE)
338 return ERR_PTR(-EINVAL);
340 /* Copy whatever fits into a cpumask. */
341 if (copy_from_user(&mask, bits, min(sizeof(struct cpumask), size)))
342 return ERR_PTR(-EFAULT);
345 * If the size was short, clear the rest of the mask;
346 * otherwise validate that the rest of the user mask was zero
347 * (we don't try hard to be efficient when validating huge masks).
349 if (size < sizeof(struct cpumask)) {
350 memset((char *)&mask + size, 0, sizeof(struct cpumask) - size);
351 } else if (size > sizeof(struct cpumask)) {
353 for (i = sizeof(struct cpumask); i < size; ++i) {
355 if (get_user(c, &bits[i]))
356 return ERR_PTR(-EFAULT);
358 return ERR_PTR(-EINVAL);
362 /* Allocate a new rectangle optimistically. */
363 rect = kmalloc(sizeof(struct hardwall_info),
364 GFP_KERNEL | __GFP_ZERO);
366 return ERR_PTR(-ENOMEM);
367 INIT_LIST_HEAD(&rect->task_head);
369 /* Compute the rectangle size and validate that it's plausible. */
370 rc = setup_rectangle(rect, &mask);
376 /* Confirm it doesn't overlap and add it to the list. */
377 spin_lock_irqsave(&hardwall_lock, flags);
378 list_for_each_entry(iter, &rectangles, list) {
379 if (overlaps(iter, rect)) {
380 spin_unlock_irqrestore(&hardwall_lock, flags);
382 return ERR_PTR(-EBUSY);
385 list_add_tail(&rect->list, &rectangles);
386 spin_unlock_irqrestore(&hardwall_lock, flags);
388 /* Set up appropriate hardwalling on all affected cpus. */
389 hardwall_setup(rect);
394 /* Activate a given hardwall on this cpu for this process. */
395 static int hardwall_activate(struct hardwall_info *rect)
399 struct task_struct *p = current;
400 struct thread_struct *ts = &p->thread;
402 /* Require a rectangle. */
406 /* Not allowed to activate a rectangle that is being torn down. */
407 if (rect->teardown_in_progress)
411 * Get our affinity; if we're not bound to this tile uniquely,
412 * we can't access the network registers.
414 if (cpumask_weight(&p->cpus_allowed) != 1)
417 /* Make sure we are bound to a cpu in this rectangle. */
418 cpu = smp_processor_id();
419 BUG_ON(cpumask_first(&p->cpus_allowed) != cpu);
422 if (!contains(rect, x, y))
425 /* If we are already bound to this hardwall, it's a no-op. */
427 BUG_ON(ts->hardwall != rect);
431 /* Success! This process gets to use the user networks on this cpu. */
433 spin_lock_irqsave(&hardwall_lock, flags);
434 list_add(&ts->hardwall_list, &rect->task_head);
435 spin_unlock_irqrestore(&hardwall_lock, flags);
436 grant_network_mpls();
437 printk(KERN_DEBUG "Pid %d (%s) activated for hardwall: cpu %d\n",
438 p->pid, p->comm, cpu);
443 * Deactivate a task's hardwall. Must hold hardwall_lock.
444 * This method may be called from free_task(), so we don't want to
445 * rely on too many fields of struct task_struct still being valid.
446 * We assume the cpus_allowed, pid, and comm fields are still valid.
448 static void _hardwall_deactivate(struct task_struct *task)
450 struct thread_struct *ts = &task->thread;
452 if (cpumask_weight(&task->cpus_allowed) != 1) {
453 pr_err("pid %d (%s) releasing networks with"
454 " an affinity mask containing %d cpus!\n",
455 task->pid, task->comm,
456 cpumask_weight(&task->cpus_allowed));
460 BUG_ON(ts->hardwall == NULL);
462 list_del(&ts->hardwall_list);
464 restrict_network_mpls();
467 /* Deactivate a task's hardwall. */
468 int hardwall_deactivate(struct task_struct *task)
473 spin_lock_irqsave(&hardwall_lock, flags);
474 activated = (task->thread.hardwall != NULL);
476 _hardwall_deactivate(task);
477 spin_unlock_irqrestore(&hardwall_lock, flags);
482 printk(KERN_DEBUG "Pid %d (%s) deactivated for hardwall: cpu %d\n",
483 task->pid, task->comm, smp_processor_id());
487 /* Stop a UDN switch before draining the network. */
488 static void stop_udn_switch(void *ignored)
490 #if !CHIP_HAS_REV1_XDN()
491 /* Freeze the switch and the demux. */
492 __insn_mtspr(SPR_UDN_SP_FREEZE,
493 SPR_UDN_SP_FREEZE__SP_FRZ_MASK |
494 SPR_UDN_SP_FREEZE__DEMUX_FRZ_MASK |
495 SPR_UDN_SP_FREEZE__NON_DEST_EXT_MASK);
499 /* Drain all the state from a stopped switch. */
500 static void drain_udn_switch(void *ignored)
502 #if !CHIP_HAS_REV1_XDN()
504 int from_tile_words, ca_count;
506 /* Empty out the 5 switch point fifos. */
507 for (i = 0; i < 5; i++) {
509 __insn_mtspr(SPR_UDN_SP_FIFO_SEL, i);
510 words = __insn_mfspr(SPR_UDN_SP_STATE) & 0xF;
511 for (j = 0; j < words; j++)
512 (void) __insn_mfspr(SPR_UDN_SP_FIFO_DATA);
513 BUG_ON((__insn_mfspr(SPR_UDN_SP_STATE) & 0xF) != 0);
516 /* Dump out the 3 word fifo at top. */
517 from_tile_words = (__insn_mfspr(SPR_UDN_DEMUX_STATUS) >> 10) & 0x3;
518 for (i = 0; i < from_tile_words; i++)
519 (void) __insn_mfspr(SPR_UDN_DEMUX_WRITE_FIFO);
521 /* Empty out demuxes. */
522 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 0))
523 (void) __tile_udn0_receive();
524 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 1))
525 (void) __tile_udn1_receive();
526 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 2))
527 (void) __tile_udn2_receive();
528 while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 3))
529 (void) __tile_udn3_receive();
530 BUG_ON((__insn_mfspr(SPR_UDN_DATA_AVAIL) & 0xF) != 0);
532 /* Empty out catch all. */
533 ca_count = __insn_mfspr(SPR_UDN_DEMUX_CA_COUNT);
534 for (i = 0; i < ca_count; i++)
535 (void) __insn_mfspr(SPR_UDN_CA_DATA);
536 BUG_ON(__insn_mfspr(SPR_UDN_DEMUX_CA_COUNT) != 0);
538 /* Clear demux logic. */
539 __insn_mtspr(SPR_UDN_DEMUX_CTL, 1);
542 * Write switch state; experimentation indicates that 0xc3000
543 * is an idle switch point.
545 for (i = 0; i < 5; i++) {
546 __insn_mtspr(SPR_UDN_SP_FIFO_SEL, i);
547 __insn_mtspr(SPR_UDN_SP_STATE, 0xc3000);
552 /* Reset random UDN state registers at boot up and during hardwall teardown. */
553 void reset_network_state(void)
555 #if !CHIP_HAS_REV1_XDN()
556 /* Reset UDN coordinates to their standard value */
557 unsigned int cpu = smp_processor_id();
558 unsigned int x = cpu % smp_width;
559 unsigned int y = cpu / smp_width;
565 #if !CHIP_HAS_REV1_XDN()
566 __insn_mtspr(SPR_UDN_TILE_COORD, (x << 18) | (y << 7));
568 /* Set demux tags to predefined values and enable them. */
569 __insn_mtspr(SPR_UDN_TAG_VALID, 0xf);
570 __insn_mtspr(SPR_UDN_TAG_0, (1 << 0));
571 __insn_mtspr(SPR_UDN_TAG_1, (1 << 1));
572 __insn_mtspr(SPR_UDN_TAG_2, (1 << 2));
573 __insn_mtspr(SPR_UDN_TAG_3, (1 << 3));
576 /* Clear out other random registers so we have a clean slate. */
577 __insn_mtspr(SPR_UDN_AVAIL_EN, 0);
578 __insn_mtspr(SPR_UDN_DEADLOCK_TIMEOUT, 0);
579 #if !CHIP_HAS_REV1_XDN()
580 __insn_mtspr(SPR_UDN_REFILL_EN, 0);
581 __insn_mtspr(SPR_UDN_DEMUX_QUEUE_SEL, 0);
582 __insn_mtspr(SPR_UDN_SP_FIFO_SEL, 0);
585 /* Start the switch and demux. */
586 #if !CHIP_HAS_REV1_XDN()
587 __insn_mtspr(SPR_UDN_SP_FREEZE, 0);
591 /* Restart a UDN switch after draining. */
592 static void restart_udn_switch(void *ignored)
594 reset_network_state();
596 /* Disable firewall interrupts. */
597 __insn_mtspr(SPR_UDN_DIRECTION_PROTECT, 0);
598 disable_firewall_interrupts();
601 /* Build a struct cpumask containing all valid tiles in bounding rectangle. */
602 static void fill_mask(struct hardwall_info *r, struct cpumask *result)
606 cpumask_clear(result);
608 cpu = r->ulhc_y * smp_width + r->ulhc_x;
609 for (y = 0; y < r->height; ++y, cpu += smp_width - r->width) {
610 for (x = 0; x < r->width; ++x, ++cpu)
611 cpu_online_set(cpu, result);
615 /* Last reference to a hardwall is gone, so clear the network. */
616 static void hardwall_destroy(struct hardwall_info *rect)
618 struct task_struct *task;
622 /* Make sure this file actually represents a rectangle. */
627 * Deactivate any remaining tasks. It's possible to race with
628 * some other thread that is exiting and hasn't yet called
629 * deactivate (when freeing its thread_info), so we carefully
630 * deactivate any remaining tasks before freeing the
631 * hardwall_info object itself.
633 spin_lock_irqsave(&hardwall_lock, flags);
634 list_for_each_entry(task, &rect->task_head, thread.hardwall_list)
635 _hardwall_deactivate(task);
636 spin_unlock_irqrestore(&hardwall_lock, flags);
639 printk(KERN_DEBUG "Clearing hardwall rectangle %dx%d %d,%d\n",
640 rect->width, rect->height, rect->ulhc_x, rect->ulhc_y);
641 fill_mask(rect, &mask);
642 on_each_cpu_mask(&mask, stop_udn_switch, NULL, 1);
643 on_each_cpu_mask(&mask, drain_udn_switch, NULL, 1);
645 /* Restart switch and disable firewall. */
646 on_each_cpu_mask(&mask, restart_udn_switch, NULL, 1);
648 /* Now free the rectangle from the list. */
649 spin_lock_irqsave(&hardwall_lock, flags);
650 BUG_ON(!list_empty(&rect->task_head));
651 list_del(&rect->list);
652 spin_unlock_irqrestore(&hardwall_lock, flags);
658 * Dump hardwall state via /proc; initialized in arch/tile/sys/proc.c.
660 int proc_tile_hardwall_show(struct seq_file *sf, void *v)
662 struct hardwall_info *r;
665 seq_printf(sf, "%dx%d 0,0 pids:\n", smp_width, smp_height);
669 spin_lock_irq(&hardwall_lock);
670 list_for_each_entry(r, &rectangles, list) {
671 struct task_struct *p;
672 seq_printf(sf, "%dx%d %d,%d pids:",
673 r->width, r->height, r->ulhc_x, r->ulhc_y);
674 list_for_each_entry(p, &r->task_head, thread.hardwall_list) {
675 unsigned int cpu = cpumask_first(&p->cpus_allowed);
676 unsigned int x = cpu % smp_width;
677 unsigned int y = cpu / smp_width;
678 seq_printf(sf, " %d@%d,%d", p->pid, x, y);
680 seq_printf(sf, "\n");
682 spin_unlock_irq(&hardwall_lock);
688 * Character device support via ioctl/close.
691 static long hardwall_ioctl(struct file *file, unsigned int a, unsigned long b)
693 struct hardwall_info *rect = file->private_data;
695 if (_IOC_TYPE(a) != HARDWALL_IOCTL_BASE)
698 switch (_IOC_NR(a)) {
699 case _HARDWALL_CREATE:
704 rect = hardwall_create(_IOC_SIZE(a),
705 (const unsigned char __user *)b);
707 return PTR_ERR(rect);
708 file->private_data = rect;
711 case _HARDWALL_ACTIVATE:
712 return hardwall_activate(rect);
714 case _HARDWALL_DEACTIVATE:
715 if (current->thread.hardwall != rect)
717 return hardwall_deactivate(current);
725 static long hardwall_compat_ioctl(struct file *file,
726 unsigned int a, unsigned long b)
728 /* Sign-extend the argument so it can be used as a pointer. */
729 return hardwall_ioctl(file, a, (unsigned long)compat_ptr(b));
733 /* The user process closed the file; revoke access to user networks. */
734 static int hardwall_flush(struct file *file, fl_owner_t owner)
736 struct hardwall_info *rect = file->private_data;
737 struct task_struct *task, *tmp;
742 * NOTE: if multiple threads are activated on this hardwall
743 * file, the other threads will continue having access to the
744 * UDN until they are context-switched out and back in again.
746 * NOTE: A NULL files pointer means the task is being torn
747 * down, so in that case we also deactivate it.
749 spin_lock_irqsave(&hardwall_lock, flags);
750 list_for_each_entry_safe(task, tmp, &rect->task_head,
751 thread.hardwall_list) {
752 if (task->files == owner || task->files == NULL)
753 _hardwall_deactivate(task);
755 spin_unlock_irqrestore(&hardwall_lock, flags);
761 /* This hardwall is gone, so destroy it. */
762 static int hardwall_release(struct inode *inode, struct file *file)
764 hardwall_destroy(file->private_data);
768 static const struct file_operations dev_hardwall_fops = {
769 .open = nonseekable_open,
770 .unlocked_ioctl = hardwall_ioctl,
772 .compat_ioctl = hardwall_compat_ioctl,
774 .flush = hardwall_flush,
775 .release = hardwall_release,
778 static struct cdev hardwall_dev;
780 static int __init dev_hardwall_init(void)
785 rc = alloc_chrdev_region(&dev, 0, 1, "hardwall");
788 cdev_init(&hardwall_dev, &dev_hardwall_fops);
789 rc = cdev_add(&hardwall_dev, dev, 1);
795 late_initcall(dev_hardwall_init);