Commit | Line | Data |
---|---|---|
8b7d89d0 PP |
1 | /* Support for MMIO probes. |
2 | * Benfit many code from kprobes | |
3 | * (C) 2002 Louis Zhuang <louis.zhuang@intel.com>. | |
4 | * 2007 Alexander Eichner | |
5 | * 2008 Pekka Paalanen <pq@iki.fi> | |
6 | */ | |
7 | ||
0fd0e3da | 8 | #include <linux/list.h> |
668a6c36 | 9 | #include <linux/rculist.h> |
8b7d89d0 PP |
10 | #include <linux/spinlock.h> |
11 | #include <linux/hash.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/module.h> | |
8b7d89d0 | 14 | #include <linux/kernel.h> |
8b7d89d0 PP |
15 | #include <linux/uaccess.h> |
16 | #include <linux/ptrace.h> | |
17 | #include <linux/preempt.h> | |
f5136380 | 18 | #include <linux/percpu.h> |
0fd0e3da | 19 | #include <linux/kdebug.h> |
d61fc448 | 20 | #include <linux/mutex.h> |
970e6fa0 | 21 | #include <linux/io.h> |
8b7d89d0 | 22 | #include <asm/cacheflush.h> |
8b7d89d0 | 23 | #include <asm/tlbflush.h> |
970e6fa0 | 24 | #include <linux/errno.h> |
13829537 | 25 | #include <asm/debugreg.h> |
0fd0e3da | 26 | #include <linux/mmiotrace.h> |
8b7d89d0 | 27 | |
8b7d89d0 PP |
28 | #define KMMIO_PAGE_HASH_BITS 4 |
29 | #define KMMIO_PAGE_TABLE_SIZE (1 << KMMIO_PAGE_HASH_BITS) | |
30 | ||
0fd0e3da PP |
31 | struct kmmio_fault_page { |
32 | struct list_head list; | |
33 | struct kmmio_fault_page *release_next; | |
34 | unsigned long page; /* location of the fault page */ | |
35 | ||
36 | /* | |
37 | * Number of times this page has been registered as a part | |
38 | * of a probe. If zero, page is disarmed and this may be freed. | |
39 | * Used only by writers (RCU). | |
40 | */ | |
41 | int count; | |
42 | }; | |
43 | ||
44 | struct kmmio_delayed_release { | |
45 | struct rcu_head rcu; | |
46 | struct kmmio_fault_page *release_list; | |
47 | }; | |
48 | ||
8b7d89d0 PP |
49 | struct kmmio_context { |
50 | struct kmmio_fault_page *fpage; | |
51 | struct kmmio_probe *probe; | |
52 | unsigned long saved_flags; | |
0fd0e3da | 53 | unsigned long addr; |
8b7d89d0 PP |
54 | int active; |
55 | }; | |
56 | ||
8b7d89d0 PP |
57 | static DEFINE_SPINLOCK(kmmio_lock); |
58 | ||
13829537 | 59 | /* Protected by kmmio_lock */ |
8b7d89d0 | 60 | unsigned int kmmio_count; |
0fd0e3da PP |
61 | |
62 | /* Read-protected by RCU, write-protected by kmmio_lock. */ | |
8b7d89d0 PP |
63 | static struct list_head kmmio_page_table[KMMIO_PAGE_TABLE_SIZE]; |
64 | static LIST_HEAD(kmmio_probes); | |
65 | ||
0fd0e3da PP |
66 | static struct list_head *kmmio_page_list(unsigned long page) |
67 | { | |
68 | return &kmmio_page_table[hash_long(page, KMMIO_PAGE_HASH_BITS)]; | |
69 | } | |
70 | ||
f5136380 PP |
71 | /* Accessed per-cpu */ |
72 | static DEFINE_PER_CPU(struct kmmio_context, kmmio_ctx); | |
8b7d89d0 | 73 | |
8b7d89d0 PP |
74 | /* |
75 | * this is basically a dynamic stabbing problem: | |
76 | * Could use the existing prio tree code or | |
77 | * Possible better implementations: | |
78 | * The Interval Skip List: A Data Structure for Finding All Intervals That | |
79 | * Overlap a Point (might be simple) | |
80 | * Space Efficient Dynamic Stabbing with Fast Queries - Mikkel Thorup | |
81 | */ | |
0fd0e3da | 82 | /* Get the kmmio at this addr (if any). You must be holding RCU read lock. */ |
8b7d89d0 PP |
83 | static struct kmmio_probe *get_kmmio_probe(unsigned long addr) |
84 | { | |
85 | struct kmmio_probe *p; | |
0fd0e3da | 86 | list_for_each_entry_rcu(p, &kmmio_probes, list) { |
8b7d89d0 PP |
87 | if (addr >= p->addr && addr <= (p->addr + p->len)) |
88 | return p; | |
89 | } | |
90 | return NULL; | |
91 | } | |
92 | ||
0fd0e3da | 93 | /* You must be holding RCU read lock. */ |
8b7d89d0 PP |
94 | static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long page) |
95 | { | |
0fd0e3da PP |
96 | struct list_head *head; |
97 | struct kmmio_fault_page *p; | |
8b7d89d0 PP |
98 | |
99 | page &= PAGE_MASK; | |
0fd0e3da PP |
100 | head = kmmio_page_list(page); |
101 | list_for_each_entry_rcu(p, head, list) { | |
8b7d89d0 PP |
102 | if (p->page == page) |
103 | return p; | |
104 | } | |
8b7d89d0 PP |
105 | return NULL; |
106 | } | |
107 | ||
790e2a29 PP |
108 | static void set_page_present(unsigned long addr, bool present, |
109 | unsigned int *pglevel) | |
8b7d89d0 | 110 | { |
13829537 PP |
111 | pteval_t pteval; |
112 | pmdval_t pmdval; | |
790e2a29 | 113 | unsigned int level; |
13829537 PP |
114 | pmd_t *pmd; |
115 | pte_t *pte = lookup_address(addr, &level); | |
8b7d89d0 | 116 | |
75bb8835 | 117 | if (!pte) { |
13829537 | 118 | pr_err("kmmio: no pte for page 0x%08lx\n", addr); |
75bb8835 PP |
119 | return; |
120 | } | |
121 | ||
13829537 PP |
122 | if (pglevel) |
123 | *pglevel = level; | |
124 | ||
125 | switch (level) { | |
126 | case PG_LEVEL_2M: | |
127 | pmd = (pmd_t *)pte; | |
128 | pmdval = pmd_val(*pmd) & ~_PAGE_PRESENT; | |
129 | if (present) | |
130 | pmdval |= _PAGE_PRESENT; | |
131 | set_pmd(pmd, __pmd(pmdval)); | |
132 | break; | |
133 | ||
134 | case PG_LEVEL_4K: | |
135 | pteval = pte_val(*pte) & ~_PAGE_PRESENT; | |
136 | if (present) | |
137 | pteval |= _PAGE_PRESENT; | |
138 | set_pte_atomic(pte, __pte(pteval)); | |
139 | break; | |
140 | ||
141 | default: | |
142 | pr_err("kmmio: unexpected page level 0x%x.\n", level); | |
143 | return; | |
8b7d89d0 PP |
144 | } |
145 | ||
13829537 PP |
146 | __flush_tlb_one(addr); |
147 | } | |
75bb8835 | 148 | |
13829537 | 149 | /** Mark the given page as not present. Access to it will trigger a fault. */ |
790e2a29 | 150 | static void arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel) |
13829537 | 151 | { |
790e2a29 | 152 | set_page_present(page & PAGE_MASK, false, pglevel); |
8b7d89d0 PP |
153 | } |
154 | ||
0fd0e3da | 155 | /** Mark the given page as present. */ |
790e2a29 | 156 | static void disarm_kmmio_fault_page(unsigned long page, unsigned int *pglevel) |
8b7d89d0 | 157 | { |
790e2a29 | 158 | set_page_present(page & PAGE_MASK, true, pglevel); |
8b7d89d0 PP |
159 | } |
160 | ||
0fd0e3da PP |
161 | /* |
162 | * This is being called from do_page_fault(). | |
163 | * | |
164 | * We may be in an interrupt or a critical section. Also prefecthing may | |
165 | * trigger a page fault. We may be in the middle of process switch. | |
166 | * We cannot take any locks, because we could be executing especially | |
167 | * within a kmmio critical section. | |
168 | * | |
169 | * Local interrupts are disabled, so preemption cannot happen. | |
170 | * Do not enable interrupts, do not sleep, and watch out for other CPUs. | |
171 | */ | |
8b7d89d0 PP |
172 | /* |
173 | * Interrupts are disabled on entry as trap3 is an interrupt gate | |
174 | * and they remain disabled thorough out this function. | |
175 | */ | |
0fd0e3da | 176 | int kmmio_handler(struct pt_regs *regs, unsigned long addr) |
8b7d89d0 | 177 | { |
0fd0e3da PP |
178 | struct kmmio_context *ctx; |
179 | struct kmmio_fault_page *faultpage; | |
13829537 | 180 | int ret = 0; /* default to fault not handled */ |
8b7d89d0 PP |
181 | |
182 | /* | |
183 | * Preemption is now disabled to prevent process switch during | |
184 | * single stepping. We can only handle one active kmmio trace | |
185 | * per cpu, so ensure that we finish it before something else | |
d61fc448 PP |
186 | * gets to run. We also hold the RCU read lock over single |
187 | * stepping to avoid looking up the probe and kmmio_fault_page | |
188 | * again. | |
8b7d89d0 PP |
189 | */ |
190 | preempt_disable(); | |
0fd0e3da | 191 | rcu_read_lock(); |
d61fc448 | 192 | |
0fd0e3da PP |
193 | faultpage = get_kmmio_fault_page(addr); |
194 | if (!faultpage) { | |
195 | /* | |
196 | * Either this page fault is not caused by kmmio, or | |
197 | * another CPU just pulled the kmmio probe from under | |
13829537 | 198 | * our feet. The latter case should not be possible. |
0fd0e3da PP |
199 | */ |
200 | goto no_kmmio; | |
201 | } | |
202 | ||
203 | ctx = &get_cpu_var(kmmio_ctx); | |
8b7d89d0 | 204 | if (ctx->active) { |
13829537 PP |
205 | disarm_kmmio_fault_page(faultpage->page, NULL); |
206 | if (addr == ctx->addr) { | |
207 | /* | |
208 | * On SMP we sometimes get recursive probe hits on the | |
209 | * same address. Context is already saved, fall out. | |
210 | */ | |
211 | pr_debug("kmmio: duplicate probe hit on CPU %d, for " | |
212 | "address 0x%08lx.\n", | |
213 | smp_processor_id(), addr); | |
214 | ret = 1; | |
215 | goto no_kmmio_ctx; | |
216 | } | |
8b7d89d0 | 217 | /* |
0fd0e3da | 218 | * Prevent overwriting already in-flight context. |
13829537 PP |
219 | * This should not happen, let's hope disarming at least |
220 | * prevents a panic. | |
8b7d89d0 | 221 | */ |
0fd0e3da PP |
222 | pr_emerg("kmmio: recursive probe hit on CPU %d, " |
223 | "for address 0x%08lx. Ignoring.\n", | |
f5136380 | 224 | smp_processor_id(), addr); |
13829537 PP |
225 | pr_emerg("kmmio: previous hit was at 0x%08lx.\n", |
226 | ctx->addr); | |
0fd0e3da | 227 | goto no_kmmio_ctx; |
8b7d89d0 PP |
228 | } |
229 | ctx->active++; | |
230 | ||
0fd0e3da | 231 | ctx->fpage = faultpage; |
8b7d89d0 | 232 | ctx->probe = get_kmmio_probe(addr); |
49023168 | 233 | ctx->saved_flags = (regs->flags & (X86_EFLAGS_TF | X86_EFLAGS_IF)); |
0fd0e3da | 234 | ctx->addr = addr; |
8b7d89d0 PP |
235 | |
236 | if (ctx->probe && ctx->probe->pre_handler) | |
237 | ctx->probe->pre_handler(ctx->probe, regs, addr); | |
238 | ||
d61fc448 PP |
239 | /* |
240 | * Enable single-stepping and disable interrupts for the faulting | |
241 | * context. Local interrupts must not get enabled during stepping. | |
242 | */ | |
49023168 IM |
243 | regs->flags |= X86_EFLAGS_TF; |
244 | regs->flags &= ~X86_EFLAGS_IF; | |
8b7d89d0 | 245 | |
0fd0e3da | 246 | /* Now we set present bit in PTE and single step. */ |
8b7d89d0 PP |
247 | disarm_kmmio_fault_page(ctx->fpage->page, NULL); |
248 | ||
d61fc448 PP |
249 | /* |
250 | * If another cpu accesses the same page while we are stepping, | |
251 | * the access will not be caught. It will simply succeed and the | |
252 | * only downside is we lose the event. If this becomes a problem, | |
253 | * the user should drop to single cpu before tracing. | |
254 | */ | |
255 | ||
f5136380 | 256 | put_cpu_var(kmmio_ctx); |
13829537 | 257 | return 1; /* fault handled */ |
8b7d89d0 | 258 | |
0fd0e3da PP |
259 | no_kmmio_ctx: |
260 | put_cpu_var(kmmio_ctx); | |
8b7d89d0 | 261 | no_kmmio: |
0fd0e3da | 262 | rcu_read_unlock(); |
8b7d89d0 | 263 | preempt_enable_no_resched(); |
13829537 | 264 | return ret; |
8b7d89d0 PP |
265 | } |
266 | ||
267 | /* | |
268 | * Interrupts are disabled on entry as trap1 is an interrupt gate | |
269 | * and they remain disabled thorough out this function. | |
0fd0e3da | 270 | * This must always get called as the pair to kmmio_handler(). |
8b7d89d0 PP |
271 | */ |
272 | static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs) | |
273 | { | |
f5136380 PP |
274 | int ret = 0; |
275 | struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx); | |
8b7d89d0 | 276 | |
13829537 PP |
277 | if (!ctx->active) { |
278 | pr_debug("kmmio: spurious debug trap on CPU %d.\n", | |
279 | smp_processor_id()); | |
f5136380 | 280 | goto out; |
13829537 | 281 | } |
8b7d89d0 PP |
282 | |
283 | if (ctx->probe && ctx->probe->post_handler) | |
284 | ctx->probe->post_handler(ctx->probe, condition, regs); | |
285 | ||
d61fc448 | 286 | arm_kmmio_fault_page(ctx->fpage->page, NULL); |
8b7d89d0 | 287 | |
49023168 | 288 | regs->flags &= ~X86_EFLAGS_TF; |
8b7d89d0 PP |
289 | regs->flags |= ctx->saved_flags; |
290 | ||
291 | /* These were acquired in kmmio_handler(). */ | |
292 | ctx->active--; | |
0fd0e3da | 293 | BUG_ON(ctx->active); |
d61fc448 | 294 | rcu_read_unlock(); |
8b7d89d0 PP |
295 | preempt_enable_no_resched(); |
296 | ||
297 | /* | |
298 | * if somebody else is singlestepping across a probe point, flags | |
299 | * will have TF set, in which case, continue the remaining processing | |
300 | * of do_debug, as if this is not a probe hit. | |
301 | */ | |
49023168 | 302 | if (!(regs->flags & X86_EFLAGS_TF)) |
f5136380 | 303 | ret = 1; |
f5136380 PP |
304 | out: |
305 | put_cpu_var(kmmio_ctx); | |
306 | return ret; | |
8b7d89d0 PP |
307 | } |
308 | ||
0fd0e3da | 309 | /* You must be holding kmmio_lock. */ |
8b7d89d0 PP |
310 | static int add_kmmio_fault_page(unsigned long page) |
311 | { | |
312 | struct kmmio_fault_page *f; | |
313 | ||
314 | page &= PAGE_MASK; | |
315 | f = get_kmmio_fault_page(page); | |
316 | if (f) { | |
0fd0e3da PP |
317 | if (!f->count) |
318 | arm_kmmio_fault_page(f->page, NULL); | |
8b7d89d0 PP |
319 | f->count++; |
320 | return 0; | |
321 | } | |
322 | ||
323 | f = kmalloc(sizeof(*f), GFP_ATOMIC); | |
324 | if (!f) | |
325 | return -1; | |
326 | ||
327 | f->count = 1; | |
328 | f->page = page; | |
0fd0e3da | 329 | list_add_rcu(&f->list, kmmio_page_list(f->page)); |
8b7d89d0 PP |
330 | |
331 | arm_kmmio_fault_page(f->page, NULL); | |
332 | ||
333 | return 0; | |
334 | } | |
335 | ||
0fd0e3da PP |
336 | /* You must be holding kmmio_lock. */ |
337 | static void release_kmmio_fault_page(unsigned long page, | |
338 | struct kmmio_fault_page **release_list) | |
8b7d89d0 PP |
339 | { |
340 | struct kmmio_fault_page *f; | |
341 | ||
342 | page &= PAGE_MASK; | |
343 | f = get_kmmio_fault_page(page); | |
344 | if (!f) | |
345 | return; | |
346 | ||
347 | f->count--; | |
0fd0e3da | 348 | BUG_ON(f->count < 0); |
8b7d89d0 PP |
349 | if (!f->count) { |
350 | disarm_kmmio_fault_page(f->page, NULL); | |
0fd0e3da PP |
351 | f->release_next = *release_list; |
352 | *release_list = f; | |
8b7d89d0 PP |
353 | } |
354 | } | |
355 | ||
87e547fe PP |
356 | /* |
357 | * With page-unaligned ioremaps, one or two armed pages may contain | |
358 | * addresses from outside the intended mapping. Events for these addresses | |
359 | * are currently silently dropped. The events may result only from programming | |
360 | * mistakes by accessing addresses before the beginning or past the end of a | |
361 | * mapping. | |
362 | */ | |
8b7d89d0 PP |
363 | int register_kmmio_probe(struct kmmio_probe *p) |
364 | { | |
d61fc448 | 365 | unsigned long flags; |
8b7d89d0 PP |
366 | int ret = 0; |
367 | unsigned long size = 0; | |
87e547fe | 368 | const unsigned long size_lim = p->len + (p->addr & ~PAGE_MASK); |
8b7d89d0 | 369 | |
d61fc448 | 370 | spin_lock_irqsave(&kmmio_lock, flags); |
8b7d89d0 PP |
371 | if (get_kmmio_probe(p->addr)) { |
372 | ret = -EEXIST; | |
373 | goto out; | |
374 | } | |
d61fc448 | 375 | kmmio_count++; |
0fd0e3da | 376 | list_add_rcu(&p->list, &kmmio_probes); |
87e547fe | 377 | while (size < size_lim) { |
8b7d89d0 | 378 | if (add_kmmio_fault_page(p->addr + size)) |
0fd0e3da | 379 | pr_err("kmmio: Unable to set page fault.\n"); |
8b7d89d0 PP |
380 | size += PAGE_SIZE; |
381 | } | |
8b7d89d0 | 382 | out: |
d61fc448 | 383 | spin_unlock_irqrestore(&kmmio_lock, flags); |
8b7d89d0 PP |
384 | /* |
385 | * XXX: What should I do here? | |
386 | * Here was a call to global_flush_tlb(), but it does not exist | |
0fd0e3da | 387 | * anymore. It seems it's not needed after all. |
8b7d89d0 PP |
388 | */ |
389 | return ret; | |
390 | } | |
0fd0e3da | 391 | EXPORT_SYMBOL(register_kmmio_probe); |
8b7d89d0 | 392 | |
0fd0e3da PP |
393 | static void rcu_free_kmmio_fault_pages(struct rcu_head *head) |
394 | { | |
395 | struct kmmio_delayed_release *dr = container_of( | |
396 | head, | |
397 | struct kmmio_delayed_release, | |
398 | rcu); | |
399 | struct kmmio_fault_page *p = dr->release_list; | |
400 | while (p) { | |
401 | struct kmmio_fault_page *next = p->release_next; | |
402 | BUG_ON(p->count); | |
403 | kfree(p); | |
404 | p = next; | |
405 | } | |
406 | kfree(dr); | |
407 | } | |
408 | ||
409 | static void remove_kmmio_fault_pages(struct rcu_head *head) | |
410 | { | |
411 | struct kmmio_delayed_release *dr = container_of( | |
412 | head, | |
413 | struct kmmio_delayed_release, | |
414 | rcu); | |
415 | struct kmmio_fault_page *p = dr->release_list; | |
416 | struct kmmio_fault_page **prevp = &dr->release_list; | |
417 | unsigned long flags; | |
418 | spin_lock_irqsave(&kmmio_lock, flags); | |
419 | while (p) { | |
420 | if (!p->count) | |
421 | list_del_rcu(&p->list); | |
422 | else | |
423 | *prevp = p->release_next; | |
424 | prevp = &p->release_next; | |
425 | p = p->release_next; | |
426 | } | |
427 | spin_unlock_irqrestore(&kmmio_lock, flags); | |
428 | /* This is the real RCU destroy call. */ | |
429 | call_rcu(&dr->rcu, rcu_free_kmmio_fault_pages); | |
430 | } | |
431 | ||
432 | /* | |
433 | * Remove a kmmio probe. You have to synchronize_rcu() before you can be | |
d61fc448 PP |
434 | * sure that the callbacks will not be called anymore. Only after that |
435 | * you may actually release your struct kmmio_probe. | |
0fd0e3da PP |
436 | * |
437 | * Unregistering a kmmio fault page has three steps: | |
438 | * 1. release_kmmio_fault_page() | |
439 | * Disarm the page, wait a grace period to let all faults finish. | |
440 | * 2. remove_kmmio_fault_pages() | |
441 | * Remove the pages from kmmio_page_table. | |
442 | * 3. rcu_free_kmmio_fault_pages() | |
443 | * Actally free the kmmio_fault_page structs as with RCU. | |
444 | */ | |
8b7d89d0 PP |
445 | void unregister_kmmio_probe(struct kmmio_probe *p) |
446 | { | |
d61fc448 | 447 | unsigned long flags; |
8b7d89d0 | 448 | unsigned long size = 0; |
87e547fe | 449 | const unsigned long size_lim = p->len + (p->addr & ~PAGE_MASK); |
0fd0e3da PP |
450 | struct kmmio_fault_page *release_list = NULL; |
451 | struct kmmio_delayed_release *drelease; | |
8b7d89d0 | 452 | |
d61fc448 | 453 | spin_lock_irqsave(&kmmio_lock, flags); |
87e547fe | 454 | while (size < size_lim) { |
0fd0e3da | 455 | release_kmmio_fault_page(p->addr + size, &release_list); |
8b7d89d0 PP |
456 | size += PAGE_SIZE; |
457 | } | |
0fd0e3da | 458 | list_del_rcu(&p->list); |
8b7d89d0 | 459 | kmmio_count--; |
d61fc448 | 460 | spin_unlock_irqrestore(&kmmio_lock, flags); |
8b7d89d0 | 461 | |
0fd0e3da PP |
462 | drelease = kmalloc(sizeof(*drelease), GFP_ATOMIC); |
463 | if (!drelease) { | |
464 | pr_crit("kmmio: leaking kmmio_fault_page objects.\n"); | |
465 | return; | |
466 | } | |
467 | drelease->release_list = release_list; | |
468 | ||
469 | /* | |
470 | * This is not really RCU here. We have just disarmed a set of | |
471 | * pages so that they cannot trigger page faults anymore. However, | |
472 | * we cannot remove the pages from kmmio_page_table, | |
473 | * because a probe hit might be in flight on another CPU. The | |
474 | * pages are collected into a list, and they will be removed from | |
475 | * kmmio_page_table when it is certain that no probe hit related to | |
476 | * these pages can be in flight. RCU grace period sounds like a | |
477 | * good choice. | |
478 | * | |
479 | * If we removed the pages too early, kmmio page fault handler might | |
480 | * not find the respective kmmio_fault_page and determine it's not | |
481 | * a kmmio fault, when it actually is. This would lead to madness. | |
482 | */ | |
483 | call_rcu(&drelease->rcu, remove_kmmio_fault_pages); | |
8b7d89d0 | 484 | } |
0fd0e3da | 485 | EXPORT_SYMBOL(unregister_kmmio_probe); |
8b7d89d0 PP |
486 | |
487 | static int kmmio_die_notifier(struct notifier_block *nb, unsigned long val, | |
488 | void *args) | |
489 | { | |
490 | struct die_args *arg = args; | |
491 | ||
13829537 | 492 | if (val == DIE_DEBUG && (arg->err & DR_STEP)) |
8b7d89d0 PP |
493 | if (post_kmmio_handler(arg->err, arg->regs) == 1) |
494 | return NOTIFY_STOP; | |
495 | ||
496 | return NOTIFY_DONE; | |
497 | } | |
13829537 PP |
498 | |
499 | static struct notifier_block nb_die = { | |
500 | .notifier_call = kmmio_die_notifier | |
501 | }; | |
502 | ||
503 | static int __init init_kmmio(void) | |
504 | { | |
505 | int i; | |
506 | for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) | |
507 | INIT_LIST_HEAD(&kmmio_page_table[i]); | |
508 | return register_die_notifier(&nb_die); | |
509 | } | |
510 | fs_initcall(init_kmmio); /* should be before device_initcall() */ |