xref: /openbmc/linux/include/asm-generic/tlb.h (revision 5d7800d9)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* include/asm-generic/tlb.h
3  *
4  *	Generic TLB shootdown code
5  *
6  * Copyright 2001 Red Hat, Inc.
7  * Based on code from mm/memory.c Copyright Linus Torvalds and others.
8  *
9  * Copyright 2011 Red Hat, Inc., Peter Zijlstra
10  */
11 #ifndef _ASM_GENERIC__TLB_H
12 #define _ASM_GENERIC__TLB_H
13 
14 #include <linux/mmu_notifier.h>
15 #include <linux/swap.h>
16 #include <linux/hugetlb_inline.h>
17 #include <asm/tlbflush.h>
18 #include <asm/cacheflush.h>
19 
20 /*
21  * Blindly accessing user memory from NMI context can be dangerous
22  * if we're in the middle of switching the current user task or switching
23  * the loaded mm.
24  */
25 #ifndef nmi_uaccess_okay
26 # define nmi_uaccess_okay() true
27 #endif
28 
29 #ifdef CONFIG_MMU
30 
31 /*
32  * Generic MMU-gather implementation.
33  *
34  * The mmu_gather data structure is used by the mm code to implement the
35  * correct and efficient ordering of freeing pages and TLB invalidations.
36  *
37  * This correct ordering is:
38  *
39  *  1) unhook page
40  *  2) TLB invalidate page
41  *  3) free page
42  *
43  * That is, we must never free a page before we have ensured there are no live
44  * translations left to it. Otherwise it might be possible to observe (or
45  * worse, change) the page content after it has been reused.
46  *
47  * The mmu_gather API consists of:
48  *
49  *  - tlb_gather_mmu() / tlb_gather_mmu_fullmm() / tlb_finish_mmu()
50  *
51  *    start and finish a mmu_gather
52  *
53  *    Finish in particular will issue a (final) TLB invalidate and free
54  *    all (remaining) queued pages.
55  *
56  *  - tlb_start_vma() / tlb_end_vma(); marks the start / end of a VMA
57  *
58  *    Defaults to flushing at tlb_end_vma() to reset the range; helps when
59  *    there's large holes between the VMAs.
60  *
61  *  - tlb_remove_table()
62  *
63  *    tlb_remove_table() is the basic primitive to free page-table directories
64  *    (__p*_free_tlb()).  In it's most primitive form it is an alias for
65  *    tlb_remove_page() below, for when page directories are pages and have no
66  *    additional constraints.
67  *
68  *    See also MMU_GATHER_TABLE_FREE and MMU_GATHER_RCU_TABLE_FREE.
69  *
70  *  - tlb_remove_page() / __tlb_remove_page()
71  *  - tlb_remove_page_size() / __tlb_remove_page_size()
72  *
73  *    __tlb_remove_page_size() is the basic primitive that queues a page for
74  *    freeing. __tlb_remove_page() assumes PAGE_SIZE. Both will return a
75  *    boolean indicating if the queue is (now) full and a call to
76  *    tlb_flush_mmu() is required.
77  *
78  *    tlb_remove_page() and tlb_remove_page_size() imply the call to
79  *    tlb_flush_mmu() when required and has no return value.
80  *
81  *  - tlb_change_page_size()
82  *
83  *    call before __tlb_remove_page*() to set the current page-size; implies a
84  *    possible tlb_flush_mmu() call.
85  *
86  *  - tlb_flush_mmu() / tlb_flush_mmu_tlbonly()
87  *
88  *    tlb_flush_mmu_tlbonly() - does the TLB invalidate (and resets
89  *                              related state, like the range)
90  *
91  *    tlb_flush_mmu() - in addition to the above TLB invalidate, also frees
92  *			whatever pages are still batched.
93  *
94  *  - mmu_gather::fullmm
95  *
96  *    A flag set by tlb_gather_mmu_fullmm() to indicate we're going to free
97  *    the entire mm; this allows a number of optimizations.
98  *
99  *    - We can ignore tlb_{start,end}_vma(); because we don't
100  *      care about ranges. Everything will be shot down.
101  *
102  *    - (RISC) architectures that use ASIDs can cycle to a new ASID
103  *      and delay the invalidation until ASID space runs out.
104  *
105  *  - mmu_gather::need_flush_all
106  *
107  *    A flag that can be set by the arch code if it wants to force
108  *    flush the entire TLB irrespective of the range. For instance
109  *    x86-PAE needs this when changing top-level entries.
110  *
111  * And allows the architecture to provide and implement tlb_flush():
112  *
113  * tlb_flush() may, in addition to the above mentioned mmu_gather fields, make
114  * use of:
115  *
116  *  - mmu_gather::start / mmu_gather::end
117  *
118  *    which provides the range that needs to be flushed to cover the pages to
119  *    be freed.
120  *
121  *  - mmu_gather::freed_tables
122  *
123  *    set when we freed page table pages
124  *
125  *  - tlb_get_unmap_shift() / tlb_get_unmap_size()
126  *
127  *    returns the smallest TLB entry size unmapped in this range.
128  *
129  * If an architecture does not provide tlb_flush() a default implementation
130  * based on flush_tlb_range() will be used, unless MMU_GATHER_NO_RANGE is
131  * specified, in which case we'll default to flush_tlb_mm().
132  *
133  * Additionally there are a few opt-in features:
134  *
135  *  MMU_GATHER_PAGE_SIZE
136  *
137  *  This ensures we call tlb_flush() every time tlb_change_page_size() actually
138  *  changes the size and provides mmu_gather::page_size to tlb_flush().
139  *
140  *  This might be useful if your architecture has size specific TLB
141  *  invalidation instructions.
142  *
143  *  MMU_GATHER_TABLE_FREE
144  *
145  *  This provides tlb_remove_table(), to be used instead of tlb_remove_page()
146  *  for page directores (__p*_free_tlb()).
147  *
148  *  Useful if your architecture has non-page page directories.
149  *
150  *  When used, an architecture is expected to provide __tlb_remove_table()
151  *  which does the actual freeing of these pages.
152  *
153  *  MMU_GATHER_RCU_TABLE_FREE
154  *
155  *  Like MMU_GATHER_TABLE_FREE, and adds semi-RCU semantics to the free (see
156  *  comment below).
157  *
158  *  Useful if your architecture doesn't use IPIs for remote TLB invalidates
159  *  and therefore doesn't naturally serialize with software page-table walkers.
160  *
161  *  MMU_GATHER_NO_FLUSH_CACHE
162  *
163  *  Indicates the architecture has flush_cache_range() but it needs *NOT* be called
164  *  before unmapping a VMA.
165  *
166  *  NOTE: strictly speaking we shouldn't have this knob and instead rely on
167  *	  flush_cache_range() being a NOP, except Sparc64 seems to be
168  *	  different here.
169  *
170  *  MMU_GATHER_MERGE_VMAS
171  *
172  *  Indicates the architecture wants to merge ranges over VMAs; typical when
173  *  multiple range invalidates are more expensive than a full invalidate.
174  *
175  *  MMU_GATHER_NO_RANGE
176  *
177  *  Use this if your architecture lacks an efficient flush_tlb_range(). This
178  *  option implies MMU_GATHER_MERGE_VMAS above.
179  *
180  *  MMU_GATHER_NO_GATHER
181  *
182  *  If the option is set the mmu_gather will not track individual pages for
183  *  delayed page free anymore. A platform that enables the option needs to
184  *  provide its own implementation of the __tlb_remove_page_size() function to
185  *  free pages.
186  *
187  *  This is useful if your architecture already flushes TLB entries in the
188  *  various ptep_get_and_clear() functions.
189  */
190 
191 #ifdef CONFIG_MMU_GATHER_TABLE_FREE
192 
193 struct mmu_table_batch {
194 #ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE
195 	struct rcu_head		rcu;
196 #endif
197 	unsigned int		nr;
198 	void			*tables[];
199 };
200 
201 #define MAX_TABLE_BATCH		\
202 	((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
203 
204 extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
205 
206 #else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */
207 
208 /*
209  * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based
210  * page directories and we can use the normal page batching to free them.
211  */
212 #define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page))
213 
214 #endif /* CONFIG_MMU_GATHER_TABLE_FREE */
215 
216 #ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE
217 /*
218  * This allows an architecture that does not use the linux page-tables for
219  * hardware to skip the TLBI when freeing page tables.
220  */
221 #ifndef tlb_needs_table_invalidate
222 #define tlb_needs_table_invalidate() (true)
223 #endif
224 
225 void tlb_remove_table_sync_one(void);
226 
227 #else
228 
229 #ifdef tlb_needs_table_invalidate
230 #error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE
231 #endif
232 
233 static inline void tlb_remove_table_sync_one(void) { }
234 
235 #endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */
236 
237 
238 #ifndef CONFIG_MMU_GATHER_NO_GATHER
239 /*
240  * If we can't allocate a page to make a big batch of page pointers
241  * to work on, then just handle a few from the on-stack structure.
242  */
243 #define MMU_GATHER_BUNDLE	8
244 
245 struct mmu_gather_batch {
246 	struct mmu_gather_batch	*next;
247 	unsigned int		nr;
248 	unsigned int		max;
249 	struct encoded_page	*encoded_pages[];
250 };
251 
252 #define MAX_GATHER_BATCH	\
253 	((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))
254 
255 /*
256  * Limit the maximum number of mmu_gather batches to reduce a risk of soft
257  * lockups for non-preemptible kernels on huge machines when a lot of memory
258  * is zapped during unmapping.
259  * 10K pages freed at once should be safe even without a preemption point.
260  */
261 #define MAX_GATHER_BATCH_COUNT	(10000UL/MAX_GATHER_BATCH)
262 
263 extern bool __tlb_remove_page_size(struct mmu_gather *tlb,
264 				   struct encoded_page *page,
265 				   int page_size);
266 
267 #ifdef CONFIG_SMP
268 /*
269  * This both sets 'delayed_rmap', and returns true. It would be an inline
270  * function, except we define it before the 'struct mmu_gather'.
271  */
272 #define tlb_delay_rmap(tlb) (((tlb)->delayed_rmap = 1), true)
273 extern void tlb_flush_rmaps(struct mmu_gather *tlb, struct vm_area_struct *vma);
274 #endif
275 
276 #endif
277 
278 /*
279  * We have a no-op version of the rmap removal that doesn't
280  * delay anything. That is used on S390, which flushes remote
281  * TLBs synchronously, and on UP, which doesn't have any
282  * remote TLBs to flush and is not preemptible due to this
283  * all happening under the page table lock.
284  */
285 #ifndef tlb_delay_rmap
286 #define tlb_delay_rmap(tlb) (false)
287 static inline void tlb_flush_rmaps(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
288 #endif
289 
290 /*
291  * struct mmu_gather is an opaque type used by the mm code for passing around
292  * any data needed by arch specific code for tlb_remove_page.
293  */
294 struct mmu_gather {
295 	struct mm_struct	*mm;
296 
297 #ifdef CONFIG_MMU_GATHER_TABLE_FREE
298 	struct mmu_table_batch	*batch;
299 #endif
300 
301 	unsigned long		start;
302 	unsigned long		end;
303 	/*
304 	 * we are in the middle of an operation to clear
305 	 * a full mm and can make some optimizations
306 	 */
307 	unsigned int		fullmm : 1;
308 
309 	/*
310 	 * we have performed an operation which
311 	 * requires a complete flush of the tlb
312 	 */
313 	unsigned int		need_flush_all : 1;
314 
315 	/*
316 	 * we have removed page directories
317 	 */
318 	unsigned int		freed_tables : 1;
319 
320 	/*
321 	 * Do we have pending delayed rmap removals?
322 	 */
323 	unsigned int		delayed_rmap : 1;
324 
325 	/*
326 	 * at which levels have we cleared entries?
327 	 */
328 	unsigned int		cleared_ptes : 1;
329 	unsigned int		cleared_pmds : 1;
330 	unsigned int		cleared_puds : 1;
331 	unsigned int		cleared_p4ds : 1;
332 
333 	/*
334 	 * tracks VM_EXEC | VM_HUGETLB in tlb_start_vma
335 	 */
336 	unsigned int		vma_exec : 1;
337 	unsigned int		vma_huge : 1;
338 	unsigned int		vma_pfn  : 1;
339 
340 	unsigned int		batch_count;
341 
342 #ifndef CONFIG_MMU_GATHER_NO_GATHER
343 	struct mmu_gather_batch *active;
344 	struct mmu_gather_batch	local;
345 	struct page		*__pages[MMU_GATHER_BUNDLE];
346 
347 #ifdef CONFIG_MMU_GATHER_PAGE_SIZE
348 	unsigned int page_size;
349 #endif
350 #endif
351 };
352 
353 void tlb_flush_mmu(struct mmu_gather *tlb);
354 
355 static inline void __tlb_adjust_range(struct mmu_gather *tlb,
356 				      unsigned long address,
357 				      unsigned int range_size)
358 {
359 	tlb->start = min(tlb->start, address);
360 	tlb->end = max(tlb->end, address + range_size);
361 }
362 
363 static inline void __tlb_reset_range(struct mmu_gather *tlb)
364 {
365 	if (tlb->fullmm) {
366 		tlb->start = tlb->end = ~0;
367 	} else {
368 		tlb->start = TASK_SIZE;
369 		tlb->end = 0;
370 	}
371 	tlb->freed_tables = 0;
372 	tlb->cleared_ptes = 0;
373 	tlb->cleared_pmds = 0;
374 	tlb->cleared_puds = 0;
375 	tlb->cleared_p4ds = 0;
376 	/*
377 	 * Do not reset mmu_gather::vma_* fields here, we do not
378 	 * call into tlb_start_vma() again to set them if there is an
379 	 * intermediate flush.
380 	 */
381 }
382 
383 #ifdef CONFIG_MMU_GATHER_NO_RANGE
384 
385 #if defined(tlb_flush)
386 #error MMU_GATHER_NO_RANGE relies on default tlb_flush()
387 #endif
388 
389 /*
390  * When an architecture does not have efficient means of range flushing TLBs
391  * there is no point in doing intermediate flushes on tlb_end_vma() to keep the
392  * range small. We equally don't have to worry about page granularity or other
393  * things.
394  *
395  * All we need to do is issue a full flush for any !0 range.
396  */
397 static inline void tlb_flush(struct mmu_gather *tlb)
398 {
399 	if (tlb->end)
400 		flush_tlb_mm(tlb->mm);
401 }
402 
403 #else /* CONFIG_MMU_GATHER_NO_RANGE */
404 
405 #ifndef tlb_flush
406 /*
407  * When an architecture does not provide its own tlb_flush() implementation
408  * but does have a reasonably efficient flush_vma_range() implementation
409  * use that.
410  */
411 static inline void tlb_flush(struct mmu_gather *tlb)
412 {
413 	if (tlb->fullmm || tlb->need_flush_all) {
414 		flush_tlb_mm(tlb->mm);
415 	} else if (tlb->end) {
416 		struct vm_area_struct vma = {
417 			.vm_mm = tlb->mm,
418 			.vm_flags = (tlb->vma_exec ? VM_EXEC    : 0) |
419 				    (tlb->vma_huge ? VM_HUGETLB : 0),
420 		};
421 
422 		flush_tlb_range(&vma, tlb->start, tlb->end);
423 	}
424 }
425 #endif
426 
427 #endif /* CONFIG_MMU_GATHER_NO_RANGE */
428 
429 static inline void
430 tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma)
431 {
432 	/*
433 	 * flush_tlb_range() implementations that look at VM_HUGETLB (tile,
434 	 * mips-4k) flush only large pages.
435 	 *
436 	 * flush_tlb_range() implementations that flush I-TLB also flush D-TLB
437 	 * (tile, xtensa, arm), so it's ok to just add VM_EXEC to an existing
438 	 * range.
439 	 *
440 	 * We rely on tlb_end_vma() to issue a flush, such that when we reset
441 	 * these values the batch is empty.
442 	 */
443 	tlb->vma_huge = is_vm_hugetlb_page(vma);
444 	tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
445 	tlb->vma_pfn  = !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP));
446 }
447 
448 static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
449 {
450 	/*
451 	 * Anything calling __tlb_adjust_range() also sets at least one of
452 	 * these bits.
453 	 */
454 	if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds ||
455 	      tlb->cleared_puds || tlb->cleared_p4ds))
456 		return;
457 
458 	tlb_flush(tlb);
459 	__tlb_reset_range(tlb);
460 }
461 
462 static inline void tlb_remove_page_size(struct mmu_gather *tlb,
463 					struct page *page, int page_size)
464 {
465 	if (__tlb_remove_page_size(tlb, encode_page(page, 0), page_size))
466 		tlb_flush_mmu(tlb);
467 }
468 
469 static __always_inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page, unsigned int flags)
470 {
471 	return __tlb_remove_page_size(tlb, encode_page(page, flags), PAGE_SIZE);
472 }
473 
474 /* tlb_remove_page
475  *	Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
476  *	required.
477  */
478 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
479 {
480 	return tlb_remove_page_size(tlb, page, PAGE_SIZE);
481 }
482 
483 static inline void tlb_change_page_size(struct mmu_gather *tlb,
484 						     unsigned int page_size)
485 {
486 #ifdef CONFIG_MMU_GATHER_PAGE_SIZE
487 	if (tlb->page_size && tlb->page_size != page_size) {
488 		if (!tlb->fullmm && !tlb->need_flush_all)
489 			tlb_flush_mmu(tlb);
490 	}
491 
492 	tlb->page_size = page_size;
493 #endif
494 }
495 
496 static inline unsigned long tlb_get_unmap_shift(struct mmu_gather *tlb)
497 {
498 	if (tlb->cleared_ptes)
499 		return PAGE_SHIFT;
500 	if (tlb->cleared_pmds)
501 		return PMD_SHIFT;
502 	if (tlb->cleared_puds)
503 		return PUD_SHIFT;
504 	if (tlb->cleared_p4ds)
505 		return P4D_SHIFT;
506 
507 	return PAGE_SHIFT;
508 }
509 
510 static inline unsigned long tlb_get_unmap_size(struct mmu_gather *tlb)
511 {
512 	return 1UL << tlb_get_unmap_shift(tlb);
513 }
514 
515 /*
516  * In the case of tlb vma handling, we can optimise these away in the
517  * case where we're doing a full MM flush.  When we're doing a munmap,
518  * the vmas are adjusted to only cover the region to be torn down.
519  */
520 static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
521 {
522 	if (tlb->fullmm)
523 		return;
524 
525 	tlb_update_vma_flags(tlb, vma);
526 #ifndef CONFIG_MMU_GATHER_NO_FLUSH_CACHE
527 	flush_cache_range(vma, vma->vm_start, vma->vm_end);
528 #endif
529 }
530 
531 static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
532 {
533 	if (tlb->fullmm)
534 		return;
535 
536 	/*
537 	 * VM_PFNMAP is more fragile because the core mm will not track the
538 	 * page mapcount -- there might not be page-frames for these PFNs after
539 	 * all. Force flush TLBs for such ranges to avoid munmap() vs
540 	 * unmap_mapping_range() races.
541 	 */
542 	if (tlb->vma_pfn || !IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS)) {
543 		/*
544 		 * Do a TLB flush and reset the range at VMA boundaries; this avoids
545 		 * the ranges growing with the unused space between consecutive VMAs.
546 		 */
547 		tlb_flush_mmu_tlbonly(tlb);
548 	}
549 }
550 
551 /*
552  * tlb_flush_{pte|pmd|pud|p4d}_range() adjust the tlb->start and tlb->end,
553  * and set corresponding cleared_*.
554  */
555 static inline void tlb_flush_pte_range(struct mmu_gather *tlb,
556 				     unsigned long address, unsigned long size)
557 {
558 	__tlb_adjust_range(tlb, address, size);
559 	tlb->cleared_ptes = 1;
560 }
561 
562 static inline void tlb_flush_pmd_range(struct mmu_gather *tlb,
563 				     unsigned long address, unsigned long size)
564 {
565 	__tlb_adjust_range(tlb, address, size);
566 	tlb->cleared_pmds = 1;
567 }
568 
569 static inline void tlb_flush_pud_range(struct mmu_gather *tlb,
570 				     unsigned long address, unsigned long size)
571 {
572 	__tlb_adjust_range(tlb, address, size);
573 	tlb->cleared_puds = 1;
574 }
575 
576 static inline void tlb_flush_p4d_range(struct mmu_gather *tlb,
577 				     unsigned long address, unsigned long size)
578 {
579 	__tlb_adjust_range(tlb, address, size);
580 	tlb->cleared_p4ds = 1;
581 }
582 
583 #ifndef __tlb_remove_tlb_entry
584 #define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
585 #endif
586 
587 /**
588  * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
589  *
590  * Record the fact that pte's were really unmapped by updating the range,
591  * so we can later optimise away the tlb invalidate.   This helps when
592  * userspace is unmapping already-unmapped pages, which happens quite a lot.
593  */
594 #define tlb_remove_tlb_entry(tlb, ptep, address)		\
595 	do {							\
596 		tlb_flush_pte_range(tlb, address, PAGE_SIZE);	\
597 		__tlb_remove_tlb_entry(tlb, ptep, address);	\
598 	} while (0)
599 
600 #define tlb_remove_huge_tlb_entry(h, tlb, ptep, address)	\
601 	do {							\
602 		unsigned long _sz = huge_page_size(h);		\
603 		if (_sz >= P4D_SIZE)				\
604 			tlb_flush_p4d_range(tlb, address, _sz);	\
605 		else if (_sz >= PUD_SIZE)			\
606 			tlb_flush_pud_range(tlb, address, _sz);	\
607 		else if (_sz >= PMD_SIZE)			\
608 			tlb_flush_pmd_range(tlb, address, _sz);	\
609 		else						\
610 			tlb_flush_pte_range(tlb, address, _sz);	\
611 		__tlb_remove_tlb_entry(tlb, ptep, address);	\
612 	} while (0)
613 
614 /**
615  * tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation
616  * This is a nop so far, because only x86 needs it.
617  */
618 #ifndef __tlb_remove_pmd_tlb_entry
619 #define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0)
620 #endif
621 
622 #define tlb_remove_pmd_tlb_entry(tlb, pmdp, address)			\
623 	do {								\
624 		tlb_flush_pmd_range(tlb, address, HPAGE_PMD_SIZE);	\
625 		__tlb_remove_pmd_tlb_entry(tlb, pmdp, address);		\
626 	} while (0)
627 
628 /**
629  * tlb_remove_pud_tlb_entry - remember a pud mapping for later tlb
630  * invalidation. This is a nop so far, because only x86 needs it.
631  */
632 #ifndef __tlb_remove_pud_tlb_entry
633 #define __tlb_remove_pud_tlb_entry(tlb, pudp, address) do {} while (0)
634 #endif
635 
636 #define tlb_remove_pud_tlb_entry(tlb, pudp, address)			\
637 	do {								\
638 		tlb_flush_pud_range(tlb, address, HPAGE_PUD_SIZE);	\
639 		__tlb_remove_pud_tlb_entry(tlb, pudp, address);		\
640 	} while (0)
641 
642 /*
643  * For things like page tables caches (ie caching addresses "inside" the
644  * page tables, like x86 does), for legacy reasons, flushing an
645  * individual page had better flush the page table caches behind it. This
646  * is definitely how x86 works, for example. And if you have an
647  * architected non-legacy page table cache (which I'm not aware of
648  * anybody actually doing), you're going to have some architecturally
649  * explicit flushing for that, likely *separate* from a regular TLB entry
650  * flush, and thus you'd need more than just some range expansion..
651  *
652  * So if we ever find an architecture
653  * that would want something that odd, I think it is up to that
654  * architecture to do its own odd thing, not cause pain for others
655  * http://lkml.kernel.org/r/CA+55aFzBggoXtNXQeng5d_mRoDnaMBE5Y+URs+PHR67nUpMtaw@mail.gmail.com
656  *
657  * For now w.r.t page table cache, mark the range_size as PAGE_SIZE
658  */
659 
660 #ifndef pte_free_tlb
661 #define pte_free_tlb(tlb, ptep, address)			\
662 	do {							\
663 		tlb_flush_pmd_range(tlb, address, PAGE_SIZE);	\
664 		tlb->freed_tables = 1;				\
665 		__pte_free_tlb(tlb, ptep, address);		\
666 	} while (0)
667 #endif
668 
669 #ifndef pmd_free_tlb
670 #define pmd_free_tlb(tlb, pmdp, address)			\
671 	do {							\
672 		tlb_flush_pud_range(tlb, address, PAGE_SIZE);	\
673 		tlb->freed_tables = 1;				\
674 		__pmd_free_tlb(tlb, pmdp, address);		\
675 	} while (0)
676 #endif
677 
678 #ifndef pud_free_tlb
679 #define pud_free_tlb(tlb, pudp, address)			\
680 	do {							\
681 		tlb_flush_p4d_range(tlb, address, PAGE_SIZE);	\
682 		tlb->freed_tables = 1;				\
683 		__pud_free_tlb(tlb, pudp, address);		\
684 	} while (0)
685 #endif
686 
687 #ifndef p4d_free_tlb
688 #define p4d_free_tlb(tlb, pudp, address)			\
689 	do {							\
690 		__tlb_adjust_range(tlb, address, PAGE_SIZE);	\
691 		tlb->freed_tables = 1;				\
692 		__p4d_free_tlb(tlb, pudp, address);		\
693 	} while (0)
694 #endif
695 
696 #ifndef pte_needs_flush
697 static inline bool pte_needs_flush(pte_t oldpte, pte_t newpte)
698 {
699 	return true;
700 }
701 #endif
702 
703 #ifndef huge_pmd_needs_flush
704 static inline bool huge_pmd_needs_flush(pmd_t oldpmd, pmd_t newpmd)
705 {
706 	return true;
707 }
708 #endif
709 
710 #endif /* CONFIG_MMU */
711 
712 #endif /* _ASM_GENERIC__TLB_H */
713