85cbd3cd3723698ed51707d01fa75d8000f81477
[deliverable/linux.git] / arch / x86 / mm / pat.c
1 /*
2 * Handle caching attributes in page tables (PAT)
3 *
4 * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
5 * Suresh B Siddha <suresh.b.siddha@intel.com>
6 *
7 * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen.
8 */
9
10 #include <linux/seq_file.h>
11 #include <linux/bootmem.h>
12 #include <linux/debugfs.h>
13 #include <linux/kernel.h>
14 #include <linux/gfp.h>
15 #include <linux/mm.h>
16 #include <linux/fs.h>
17
18 #include <asm/cacheflush.h>
19 #include <asm/processor.h>
20 #include <asm/tlbflush.h>
21 #include <asm/pgtable.h>
22 #include <asm/fcntl.h>
23 #include <asm/e820.h>
24 #include <asm/mtrr.h>
25 #include <asm/page.h>
26 #include <asm/msr.h>
27 #include <asm/pat.h>
28 #include <asm/io.h>
29
30 #ifdef CONFIG_X86_PAT
31 int __read_mostly pat_enabled = 1;
32
33 void __cpuinit pat_disable(char *reason)
34 {
35 pat_enabled = 0;
36 printk(KERN_INFO "%s\n", reason);
37 }
38
39 static int __init nopat(char *str)
40 {
41 pat_disable("PAT support disabled.");
42 return 0;
43 }
44 early_param("nopat", nopat);
45 #endif
46
47
48 static int debug_enable;
49
50 static int __init pat_debug_setup(char *str)
51 {
52 debug_enable = 1;
53 return 0;
54 }
55 __setup("debugpat", pat_debug_setup);
56
57 #define dprintk(fmt, arg...) \
58 do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
59
60
61 static u64 __read_mostly boot_pat_state;
62
63 enum {
64 PAT_UC = 0, /* uncached */
65 PAT_WC = 1, /* Write combining */
66 PAT_WT = 4, /* Write Through */
67 PAT_WP = 5, /* Write Protected */
68 PAT_WB = 6, /* Write Back (default) */
69 PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */
70 };
71
72 #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
73
74 void pat_init(void)
75 {
76 u64 pat;
77
78 if (!pat_enabled)
79 return;
80
81 /* Paranoia check. */
82 if (!cpu_has_pat && boot_pat_state) {
83 /*
84 * If this happens we are on a secondary CPU, but
85 * switched to PAT on the boot CPU. We have no way to
86 * undo PAT.
87 */
88 printk(KERN_ERR "PAT enabled, "
89 "but not supported by secondary CPU\n");
90 BUG();
91 }
92
93 /* Set PWT to Write-Combining. All other bits stay the same */
94 /*
95 * PTE encoding used in Linux:
96 * PAT
97 * |PCD
98 * ||PWT
99 * |||
100 * 000 WB _PAGE_CACHE_WB
101 * 001 WC _PAGE_CACHE_WC
102 * 010 UC- _PAGE_CACHE_UC_MINUS
103 * 011 UC _PAGE_CACHE_UC
104 * PAT bit unused
105 */
106 pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
107 PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
108
109 /* Boot CPU check */
110 if (!boot_pat_state)
111 rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
112
113 wrmsrl(MSR_IA32_CR_PAT, pat);
114 printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
115 smp_processor_id(), boot_pat_state, pat);
116 }
117
118 #undef PAT
119
120 static char *cattr_name(unsigned long flags)
121 {
122 switch (flags & _PAGE_CACHE_MASK) {
123 case _PAGE_CACHE_UC: return "uncached";
124 case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
125 case _PAGE_CACHE_WB: return "write-back";
126 case _PAGE_CACHE_WC: return "write-combining";
127 default: return "broken";
128 }
129 }
130
131 /*
132 * The global memtype list keeps track of memory type for specific
133 * physical memory areas. Conflicting memory types in different
134 * mappings can cause CPU cache corruption. To avoid this we keep track.
135 *
136 * The list is sorted based on starting address and can contain multiple
137 * entries for each address (this allows reference counting for overlapping
138 * areas). All the aliases have the same cache attributes of course.
139 * Zero attributes are represented as holes.
140 *
141 * Currently the data structure is a list because the number of mappings
142 * are expected to be relatively small. If this should be a problem
143 * it could be changed to a rbtree or similar.
144 *
145 * memtype_lock protects the whole list.
146 */
147
148 struct memtype {
149 u64 start;
150 u64 end;
151 unsigned long type;
152 struct list_head nd;
153 };
154
155 static LIST_HEAD(memtype_list);
156 static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
157
158 /*
159 * Does intersection of PAT memory type and MTRR memory type and returns
160 * the resulting memory type as PAT understands it.
161 * (Type in pat and mtrr will not have same value)
162 * The intersection is based on "Effective Memory Type" tables in IA-32
163 * SDM vol 3a
164 */
165 static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
166 {
167 /*
168 * Look for MTRR hint to get the effective type in case where PAT
169 * request is for WB.
170 */
171 if (req_type == _PAGE_CACHE_WB) {
172 u8 mtrr_type;
173
174 mtrr_type = mtrr_type_lookup(start, end);
175 if (mtrr_type == MTRR_TYPE_UNCACHABLE)
176 return _PAGE_CACHE_UC;
177 if (mtrr_type == MTRR_TYPE_WRCOMB)
178 return _PAGE_CACHE_WC;
179 }
180
181 return req_type;
182 }
183
184 static int
185 chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
186 {
187 if (new->type != entry->type) {
188 if (type) {
189 new->type = entry->type;
190 *type = entry->type;
191 } else
192 goto conflict;
193 }
194
195 /* check overlaps with more than one entry in the list */
196 list_for_each_entry_continue(entry, &memtype_list, nd) {
197 if (new->end <= entry->start)
198 break;
199 else if (new->type != entry->type)
200 goto conflict;
201 }
202 return 0;
203
204 conflict:
205 printk(KERN_INFO "%s:%d conflicting memory types "
206 "%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
207 new->end, cattr_name(new->type), cattr_name(entry->type));
208 return -EBUSY;
209 }
210
211 static struct memtype *cached_entry;
212 static u64 cached_start;
213
214 /*
215 * For RAM pages, mark the pages as non WB memory type using
216 * PageNonWB (PG_arch_1). We allow only one set_memory_uc() or
217 * set_memory_wc() on a RAM page at a time before marking it as WB again.
218 * This is ok, because only one driver will be owning the page and
219 * doing set_memory_*() calls.
220 *
221 * For now, we use PageNonWB to track that the RAM page is being mapped
222 * as non WB. In future, we will have to use one more flag
223 * (or some other mechanism in page_struct) to distinguish between
224 * UC and WC mapping.
225 */
226 static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type,
227 unsigned long *new_type)
228 {
229 struct page *page;
230 u64 pfn, end_pfn;
231
232 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
233 page = pfn_to_page(pfn);
234 if (page_mapped(page) || PageNonWB(page))
235 goto out;
236
237 SetPageNonWB(page);
238 }
239 return 0;
240
241 out:
242 end_pfn = pfn;
243 for (pfn = (start >> PAGE_SHIFT); pfn < end_pfn; ++pfn) {
244 page = pfn_to_page(pfn);
245 ClearPageNonWB(page);
246 }
247
248 return -EINVAL;
249 }
250
251 static int free_ram_pages_type(u64 start, u64 end)
252 {
253 struct page *page;
254 u64 pfn, end_pfn;
255
256 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
257 page = pfn_to_page(pfn);
258 if (page_mapped(page) || !PageNonWB(page))
259 goto out;
260
261 ClearPageNonWB(page);
262 }
263 return 0;
264
265 out:
266 end_pfn = pfn;
267 for (pfn = (start >> PAGE_SHIFT); pfn < end_pfn; ++pfn) {
268 page = pfn_to_page(pfn);
269 SetPageNonWB(page);
270 }
271 return -EINVAL;
272 }
273
274 /*
275 * req_type typically has one of the:
276 * - _PAGE_CACHE_WB
277 * - _PAGE_CACHE_WC
278 * - _PAGE_CACHE_UC_MINUS
279 * - _PAGE_CACHE_UC
280 *
281 * req_type will have a special case value '-1', when requester want to inherit
282 * the memory type from mtrr (if WB), existing PAT, defaulting to UC_MINUS.
283 *
284 * If new_type is NULL, function will return an error if it cannot reserve the
285 * region with req_type. If new_type is non-NULL, function will return
286 * available type in new_type in case of no error. In case of any error
287 * it will return a negative return value.
288 */
289 int reserve_memtype(u64 start, u64 end, unsigned long req_type,
290 unsigned long *new_type)
291 {
292 struct memtype *new, *entry;
293 unsigned long actual_type;
294 struct list_head *where;
295 int is_range_ram;
296 int err = 0;
297
298 BUG_ON(start >= end); /* end is exclusive */
299
300 if (!pat_enabled) {
301 /* This is identical to page table setting without PAT */
302 if (new_type) {
303 if (req_type == -1)
304 *new_type = _PAGE_CACHE_WB;
305 else
306 *new_type = req_type & _PAGE_CACHE_MASK;
307 }
308 return 0;
309 }
310
311 /* Low ISA region is always mapped WB in page table. No need to track */
312 if (is_ISA_range(start, end - 1)) {
313 if (new_type)
314 *new_type = _PAGE_CACHE_WB;
315 return 0;
316 }
317
318 if (req_type == -1) {
319 /*
320 * Call mtrr_lookup to get the type hint. This is an
321 * optimization for /dev/mem mmap'ers into WB memory (BIOS
322 * tools and ACPI tools). Use WB request for WB memory and use
323 * UC_MINUS otherwise.
324 */
325 u8 mtrr_type = mtrr_type_lookup(start, end);
326
327 if (mtrr_type == MTRR_TYPE_WRBACK)
328 actual_type = _PAGE_CACHE_WB;
329 else
330 actual_type = _PAGE_CACHE_UC_MINUS;
331 } else {
332 actual_type = pat_x_mtrr_type(start, end,
333 req_type & _PAGE_CACHE_MASK);
334 }
335
336 is_range_ram = pagerange_is_ram(start, end);
337 if (is_range_ram == 1)
338 return reserve_ram_pages_type(start, end, req_type, new_type);
339 else if (is_range_ram < 0)
340 return -EINVAL;
341
342 new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
343 if (!new)
344 return -ENOMEM;
345
346 new->start = start;
347 new->end = end;
348 new->type = actual_type;
349
350 if (new_type)
351 *new_type = actual_type;
352
353 spin_lock(&memtype_lock);
354
355 if (cached_entry && start >= cached_start)
356 entry = cached_entry;
357 else
358 entry = list_entry(&memtype_list, struct memtype, nd);
359
360 /* Search for existing mapping that overlaps the current range */
361 where = NULL;
362 list_for_each_entry_continue(entry, &memtype_list, nd) {
363 if (end <= entry->start) {
364 where = entry->nd.prev;
365 cached_entry = list_entry(where, struct memtype, nd);
366 break;
367 } else if (start <= entry->start) { /* end > entry->start */
368 err = chk_conflict(new, entry, new_type);
369 if (!err) {
370 dprintk("Overlap at 0x%Lx-0x%Lx\n",
371 entry->start, entry->end);
372 where = entry->nd.prev;
373 cached_entry = list_entry(where,
374 struct memtype, nd);
375 }
376 break;
377 } else if (start < entry->end) { /* start > entry->start */
378 err = chk_conflict(new, entry, new_type);
379 if (!err) {
380 dprintk("Overlap at 0x%Lx-0x%Lx\n",
381 entry->start, entry->end);
382 cached_entry = list_entry(entry->nd.prev,
383 struct memtype, nd);
384
385 /*
386 * Move to right position in the linked
387 * list to add this new entry
388 */
389 list_for_each_entry_continue(entry,
390 &memtype_list, nd) {
391 if (start <= entry->start) {
392 where = entry->nd.prev;
393 break;
394 }
395 }
396 }
397 break;
398 }
399 }
400
401 if (err) {
402 printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
403 "track %s, req %s\n",
404 start, end, cattr_name(new->type), cattr_name(req_type));
405 kfree(new);
406 spin_unlock(&memtype_lock);
407
408 return err;
409 }
410
411 cached_start = start;
412
413 if (where)
414 list_add(&new->nd, where);
415 else
416 list_add_tail(&new->nd, &memtype_list);
417
418 spin_unlock(&memtype_lock);
419
420 dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
421 start, end, cattr_name(new->type), cattr_name(req_type),
422 new_type ? cattr_name(*new_type) : "-");
423
424 return err;
425 }
426
427 int free_memtype(u64 start, u64 end)
428 {
429 struct memtype *entry;
430 int err = -EINVAL;
431 int is_range_ram;
432
433 if (!pat_enabled)
434 return 0;
435
436 /* Low ISA region is always mapped WB. No need to track */
437 if (is_ISA_range(start, end - 1))
438 return 0;
439
440 is_range_ram = pagerange_is_ram(start, end);
441 if (is_range_ram == 1)
442 return free_ram_pages_type(start, end);
443 else if (is_range_ram < 0)
444 return -EINVAL;
445
446 spin_lock(&memtype_lock);
447 list_for_each_entry(entry, &memtype_list, nd) {
448 if (entry->start == start && entry->end == end) {
449 if (cached_entry == entry || cached_start == start)
450 cached_entry = NULL;
451
452 list_del(&entry->nd);
453 kfree(entry);
454 err = 0;
455 break;
456 }
457 }
458 spin_unlock(&memtype_lock);
459
460 if (err) {
461 printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
462 current->comm, current->pid, start, end);
463 }
464
465 dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
466
467 return err;
468 }
469
470
471 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
472 unsigned long size, pgprot_t vma_prot)
473 {
474 return vma_prot;
475 }
476
477 #ifdef CONFIG_STRICT_DEVMEM
478 /* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/
479 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
480 {
481 return 1;
482 }
483 #else
484 /* This check is needed to avoid cache aliasing when PAT is enabled */
485 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
486 {
487 u64 from = ((u64)pfn) << PAGE_SHIFT;
488 u64 to = from + size;
489 u64 cursor = from;
490
491 if (!pat_enabled)
492 return 1;
493
494 while (cursor < to) {
495 if (!devmem_is_allowed(pfn)) {
496 printk(KERN_INFO
497 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
498 current->comm, from, to);
499 return 0;
500 }
501 cursor += PAGE_SIZE;
502 pfn++;
503 }
504 return 1;
505 }
506 #endif /* CONFIG_STRICT_DEVMEM */
507
508 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
509 unsigned long size, pgprot_t *vma_prot)
510 {
511 u64 offset = ((u64) pfn) << PAGE_SHIFT;
512 unsigned long flags = -1;
513 int retval;
514
515 if (!range_is_allowed(pfn, size))
516 return 0;
517
518 if (file->f_flags & O_SYNC) {
519 flags = _PAGE_CACHE_UC_MINUS;
520 }
521
522 #ifdef CONFIG_X86_32
523 /*
524 * On the PPro and successors, the MTRRs are used to set
525 * memory types for physical addresses outside main memory,
526 * so blindly setting UC or PWT on those pages is wrong.
527 * For Pentiums and earlier, the surround logic should disable
528 * caching for the high addresses through the KEN pin, but
529 * we maintain the tradition of paranoia in this code.
530 */
531 if (!pat_enabled &&
532 !(boot_cpu_has(X86_FEATURE_MTRR) ||
533 boot_cpu_has(X86_FEATURE_K6_MTRR) ||
534 boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
535 boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
536 (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
537 flags = _PAGE_CACHE_UC;
538 }
539 #endif
540
541 /*
542 * With O_SYNC, we can only take UC_MINUS mapping. Fail if we cannot.
543 *
544 * Without O_SYNC, we want to get
545 * - WB for WB-able memory and no other conflicting mappings
546 * - UC_MINUS for non-WB-able memory with no other conflicting mappings
547 * - Inherit from confliting mappings otherwise
548 */
549 if (flags != -1) {
550 retval = reserve_memtype(offset, offset + size, flags, NULL);
551 } else {
552 retval = reserve_memtype(offset, offset + size, -1, &flags);
553 }
554
555 if (retval < 0)
556 return 0;
557
558 if (((pfn < max_low_pfn_mapped) ||
559 (pfn >= (1UL<<(32 - PAGE_SHIFT)) && pfn < max_pfn_mapped)) &&
560 ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
561 free_memtype(offset, offset + size);
562 printk(KERN_INFO
563 "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
564 current->comm, current->pid,
565 cattr_name(flags),
566 offset, (unsigned long long)(offset + size));
567 return 0;
568 }
569
570 *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
571 flags);
572 return 1;
573 }
574
575 void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
576 {
577 unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK);
578 u64 addr = (u64)pfn << PAGE_SHIFT;
579 unsigned long flags;
580
581 reserve_memtype(addr, addr + size, want_flags, &flags);
582 if (flags != want_flags) {
583 printk(KERN_INFO
584 "%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n",
585 current->comm, current->pid,
586 cattr_name(want_flags),
587 addr, (unsigned long long)(addr + size),
588 cattr_name(flags));
589 }
590 }
591
592 void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
593 {
594 u64 addr = (u64)pfn << PAGE_SHIFT;
595
596 free_memtype(addr, addr + size);
597 }
598
599 /*
600 * Internal interface to reserve a range of physical memory with prot.
601 * Reserved non RAM regions only and after successful reserve_memtype,
602 * this func also keeps identity mapping (if any) in sync with this new prot.
603 */
604 static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t vma_prot)
605 {
606 int is_ram = 0;
607 int id_sz, ret;
608 unsigned long flags;
609 unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK);
610
611 is_ram = pagerange_is_ram(paddr, paddr + size);
612
613 if (is_ram != 0) {
614 /*
615 * For mapping RAM pages, drivers need to call
616 * set_memory_[uc|wc|wb] directly, for reserve and free, before
617 * setting up the PTE.
618 */
619 WARN_ON_ONCE(1);
620 return 0;
621 }
622
623 ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
624 if (ret)
625 return ret;
626
627 if (flags != want_flags) {
628 free_memtype(paddr, paddr + size);
629 printk(KERN_ERR
630 "%s:%d map pfn expected mapping type %s for %Lx-%Lx, got %s\n",
631 current->comm, current->pid,
632 cattr_name(want_flags),
633 (unsigned long long)paddr,
634 (unsigned long long)(paddr + size),
635 cattr_name(flags));
636 return -EINVAL;
637 }
638
639 /* Need to keep identity mapping in sync */
640 if (paddr >= __pa(high_memory))
641 return 0;
642
643 id_sz = (__pa(high_memory) < paddr + size) ?
644 __pa(high_memory) - paddr :
645 size;
646
647 if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
648 free_memtype(paddr, paddr + size);
649 printk(KERN_ERR
650 "%s:%d reserve_pfn_range ioremap_change_attr failed %s "
651 "for %Lx-%Lx\n",
652 current->comm, current->pid,
653 cattr_name(flags),
654 (unsigned long long)paddr,
655 (unsigned long long)(paddr + size));
656 return -EINVAL;
657 }
658 return 0;
659 }
660
661 /*
662 * Internal interface to free a range of physical memory.
663 * Frees non RAM regions only.
664 */
665 static void free_pfn_range(u64 paddr, unsigned long size)
666 {
667 int is_ram;
668
669 is_ram = pagerange_is_ram(paddr, paddr + size);
670 if (is_ram == 0)
671 free_memtype(paddr, paddr + size);
672 }
673
674 /*
675 * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
676 * copied through copy_page_range().
677 *
678 * If the vma has a linear pfn mapping for the entire range, we get the prot
679 * from pte and reserve the entire vma range with single reserve_pfn_range call.
680 * Otherwise, we reserve the entire vma range, my ging through the PTEs page
681 * by page to get physical address and protection.
682 */
683 int track_pfn_vma_copy(struct vm_area_struct *vma)
684 {
685 int retval = 0;
686 unsigned long i, j;
687 resource_size_t paddr;
688 unsigned long prot;
689 unsigned long vma_start = vma->vm_start;
690 unsigned long vma_end = vma->vm_end;
691 unsigned long vma_size = vma_end - vma_start;
692
693 if (!pat_enabled)
694 return 0;
695
696 if (is_linear_pfn_mapping(vma)) {
697 /*
698 * reserve the whole chunk covered by vma. We need the
699 * starting address and protection from pte.
700 */
701 if (follow_phys(vma, vma_start, 0, &prot, &paddr)) {
702 WARN_ON_ONCE(1);
703 return -EINVAL;
704 }
705 return reserve_pfn_range(paddr, vma_size, __pgprot(prot));
706 }
707
708 /* reserve entire vma page by page, using pfn and prot from pte */
709 for (i = 0; i < vma_size; i += PAGE_SIZE) {
710 if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))
711 continue;
712
713 retval = reserve_pfn_range(paddr, PAGE_SIZE, __pgprot(prot));
714 if (retval)
715 goto cleanup_ret;
716 }
717 return 0;
718
719 cleanup_ret:
720 /* Reserve error: Cleanup partial reservation and return error */
721 for (j = 0; j < i; j += PAGE_SIZE) {
722 if (follow_phys(vma, vma_start + j, 0, &prot, &paddr))
723 continue;
724
725 free_pfn_range(paddr, PAGE_SIZE);
726 }
727
728 return retval;
729 }
730
731 /*
732 * track_pfn_vma_new is called when a _new_ pfn mapping is being established
733 * for physical range indicated by pfn and size.
734 *
735 * prot is passed in as a parameter for the new mapping. If the vma has a
736 * linear pfn mapping for the entire range reserve the entire vma range with
737 * single reserve_pfn_range call.
738 * Otherwise, we look t the pfn and size and reserve only the specified range
739 * page by page.
740 *
741 * Note that this function can be called with caller trying to map only a
742 * subrange/page inside the vma.
743 */
744 int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
745 unsigned long pfn, unsigned long size)
746 {
747 int retval = 0;
748 unsigned long i, j;
749 resource_size_t base_paddr;
750 resource_size_t paddr;
751 unsigned long vma_start = vma->vm_start;
752 unsigned long vma_end = vma->vm_end;
753 unsigned long vma_size = vma_end - vma_start;
754
755 if (!pat_enabled)
756 return 0;
757
758 if (is_linear_pfn_mapping(vma)) {
759 /* reserve the whole chunk starting from vm_pgoff */
760 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
761 return reserve_pfn_range(paddr, vma_size, prot);
762 }
763
764 /* reserve page by page using pfn and size */
765 base_paddr = (resource_size_t)pfn << PAGE_SHIFT;
766 for (i = 0; i < size; i += PAGE_SIZE) {
767 paddr = base_paddr + i;
768 retval = reserve_pfn_range(paddr, PAGE_SIZE, prot);
769 if (retval)
770 goto cleanup_ret;
771 }
772 return 0;
773
774 cleanup_ret:
775 /* Reserve error: Cleanup partial reservation and return error */
776 for (j = 0; j < i; j += PAGE_SIZE) {
777 paddr = base_paddr + j;
778 free_pfn_range(paddr, PAGE_SIZE);
779 }
780
781 return retval;
782 }
783
784 /*
785 * untrack_pfn_vma is called while unmapping a pfnmap for a region.
786 * untrack can be called for a specific region indicated by pfn and size or
787 * can be for the entire vma (in which case size can be zero).
788 */
789 void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
790 unsigned long size)
791 {
792 unsigned long i;
793 resource_size_t paddr;
794 unsigned long prot;
795 unsigned long vma_start = vma->vm_start;
796 unsigned long vma_end = vma->vm_end;
797 unsigned long vma_size = vma_end - vma_start;
798
799 if (!pat_enabled)
800 return;
801
802 if (is_linear_pfn_mapping(vma)) {
803 /* free the whole chunk starting from vm_pgoff */
804 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
805 free_pfn_range(paddr, vma_size);
806 return;
807 }
808
809 if (size != 0 && size != vma_size) {
810 /* free page by page, using pfn and size */
811 paddr = (resource_size_t)pfn << PAGE_SHIFT;
812 for (i = 0; i < size; i += PAGE_SIZE) {
813 paddr = paddr + i;
814 free_pfn_range(paddr, PAGE_SIZE);
815 }
816 } else {
817 /* free entire vma, page by page, using the pfn from pte */
818 for (i = 0; i < vma_size; i += PAGE_SIZE) {
819 if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))
820 continue;
821
822 free_pfn_range(paddr, PAGE_SIZE);
823 }
824 }
825 }
826
827 pgprot_t pgprot_writecombine(pgprot_t prot)
828 {
829 if (pat_enabled)
830 return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
831 else
832 return pgprot_noncached(prot);
833 }
834
835 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
836
837 /* get Nth element of the linked list */
838 static struct memtype *memtype_get_idx(loff_t pos)
839 {
840 struct memtype *list_node, *print_entry;
841 int i = 1;
842
843 print_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL);
844 if (!print_entry)
845 return NULL;
846
847 spin_lock(&memtype_lock);
848 list_for_each_entry(list_node, &memtype_list, nd) {
849 if (pos == i) {
850 *print_entry = *list_node;
851 spin_unlock(&memtype_lock);
852 return print_entry;
853 }
854 ++i;
855 }
856 spin_unlock(&memtype_lock);
857 kfree(print_entry);
858
859 return NULL;
860 }
861
862 static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
863 {
864 if (*pos == 0) {
865 ++*pos;
866 seq_printf(seq, "PAT memtype list:\n");
867 }
868
869 return memtype_get_idx(*pos);
870 }
871
872 static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
873 {
874 ++*pos;
875 return memtype_get_idx(*pos);
876 }
877
878 static void memtype_seq_stop(struct seq_file *seq, void *v)
879 {
880 }
881
882 static int memtype_seq_show(struct seq_file *seq, void *v)
883 {
884 struct memtype *print_entry = (struct memtype *)v;
885
886 seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
887 print_entry->start, print_entry->end);
888 kfree(print_entry);
889
890 return 0;
891 }
892
893 static struct seq_operations memtype_seq_ops = {
894 .start = memtype_seq_start,
895 .next = memtype_seq_next,
896 .stop = memtype_seq_stop,
897 .show = memtype_seq_show,
898 };
899
900 static int memtype_seq_open(struct inode *inode, struct file *file)
901 {
902 return seq_open(file, &memtype_seq_ops);
903 }
904
905 static const struct file_operations memtype_fops = {
906 .open = memtype_seq_open,
907 .read = seq_read,
908 .llseek = seq_lseek,
909 .release = seq_release,
910 };
911
912 static int __init pat_memtype_list_init(void)
913 {
914 debugfs_create_file("pat_memtype_list", S_IRUSR, arch_debugfs_dir,
915 NULL, &memtype_fops);
916 return 0;
917 }
918
919 late_initcall(pat_memtype_list_init);
920
921 #endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */
This page took 0.07047 seconds and 5 git commands to generate.