xref: /openbmc/linux/fs/proc/task_mmu.c (revision 1b36955c)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/pagewalk.h>
3 #include <linux/mm_inline.h>
4 #include <linux/hugetlb.h>
5 #include <linux/huge_mm.h>
6 #include <linux/mount.h>
7 #include <linux/seq_file.h>
8 #include <linux/highmem.h>
9 #include <linux/ptrace.h>
10 #include <linux/slab.h>
11 #include <linux/pagemap.h>
12 #include <linux/mempolicy.h>
13 #include <linux/rmap.h>
14 #include <linux/swap.h>
15 #include <linux/sched/mm.h>
16 #include <linux/swapops.h>
17 #include <linux/mmu_notifier.h>
18 #include <linux/page_idle.h>
19 #include <linux/shmem_fs.h>
20 #include <linux/uaccess.h>
21 #include <linux/pkeys.h>
22 
23 #include <asm/elf.h>
24 #include <asm/tlb.h>
25 #include <asm/tlbflush.h>
26 #include "internal.h"
27 
28 #define SEQ_PUT_DEC(str, val) \
29 		seq_put_decimal_ull_width(m, str, (val) << (PAGE_SHIFT-10), 8)
30 void task_mem(struct seq_file *m, struct mm_struct *mm)
31 {
32 	unsigned long text, lib, swap, anon, file, shmem;
33 	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
34 
35 	anon = get_mm_counter(mm, MM_ANONPAGES);
36 	file = get_mm_counter(mm, MM_FILEPAGES);
37 	shmem = get_mm_counter(mm, MM_SHMEMPAGES);
38 
39 	/*
40 	 * Note: to minimize their overhead, mm maintains hiwater_vm and
41 	 * hiwater_rss only when about to *lower* total_vm or rss.  Any
42 	 * collector of these hiwater stats must therefore get total_vm
43 	 * and rss too, which will usually be the higher.  Barriers? not
44 	 * worth the effort, such snapshots can always be inconsistent.
45 	 */
46 	hiwater_vm = total_vm = mm->total_vm;
47 	if (hiwater_vm < mm->hiwater_vm)
48 		hiwater_vm = mm->hiwater_vm;
49 	hiwater_rss = total_rss = anon + file + shmem;
50 	if (hiwater_rss < mm->hiwater_rss)
51 		hiwater_rss = mm->hiwater_rss;
52 
53 	/* split executable areas between text and lib */
54 	text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
55 	text = min(text, mm->exec_vm << PAGE_SHIFT);
56 	lib = (mm->exec_vm << PAGE_SHIFT) - text;
57 
58 	swap = get_mm_counter(mm, MM_SWAPENTS);
59 	SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
60 	SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
61 	SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
62 	SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm));
63 	SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
64 	SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
65 	SEQ_PUT_DEC(" kB\nRssAnon:\t", anon);
66 	SEQ_PUT_DEC(" kB\nRssFile:\t", file);
67 	SEQ_PUT_DEC(" kB\nRssShmem:\t", shmem);
68 	SEQ_PUT_DEC(" kB\nVmData:\t", mm->data_vm);
69 	SEQ_PUT_DEC(" kB\nVmStk:\t", mm->stack_vm);
70 	seq_put_decimal_ull_width(m,
71 		    " kB\nVmExe:\t", text >> 10, 8);
72 	seq_put_decimal_ull_width(m,
73 		    " kB\nVmLib:\t", lib >> 10, 8);
74 	seq_put_decimal_ull_width(m,
75 		    " kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8);
76 	SEQ_PUT_DEC(" kB\nVmSwap:\t", swap);
77 	seq_puts(m, " kB\n");
78 	hugetlb_report_usage(m, mm);
79 }
80 #undef SEQ_PUT_DEC
81 
82 unsigned long task_vsize(struct mm_struct *mm)
83 {
84 	return PAGE_SIZE * mm->total_vm;
85 }
86 
87 unsigned long task_statm(struct mm_struct *mm,
88 			 unsigned long *shared, unsigned long *text,
89 			 unsigned long *data, unsigned long *resident)
90 {
91 	*shared = get_mm_counter(mm, MM_FILEPAGES) +
92 			get_mm_counter(mm, MM_SHMEMPAGES);
93 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
94 								>> PAGE_SHIFT;
95 	*data = mm->data_vm + mm->stack_vm;
96 	*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
97 	return mm->total_vm;
98 }
99 
100 #ifdef CONFIG_NUMA
101 /*
102  * Save get_task_policy() for show_numa_map().
103  */
104 static void hold_task_mempolicy(struct proc_maps_private *priv)
105 {
106 	struct task_struct *task = priv->task;
107 
108 	task_lock(task);
109 	priv->task_mempolicy = get_task_policy(task);
110 	mpol_get(priv->task_mempolicy);
111 	task_unlock(task);
112 }
113 static void release_task_mempolicy(struct proc_maps_private *priv)
114 {
115 	mpol_put(priv->task_mempolicy);
116 }
117 #else
118 static void hold_task_mempolicy(struct proc_maps_private *priv)
119 {
120 }
121 static void release_task_mempolicy(struct proc_maps_private *priv)
122 {
123 }
124 #endif
125 
126 static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
127 						loff_t *ppos)
128 {
129 	struct vm_area_struct *vma = vma_next(&priv->iter);
130 
131 	if (vma) {
132 		*ppos = vma->vm_start;
133 	} else {
134 		*ppos = -2UL;
135 		vma = get_gate_vma(priv->mm);
136 	}
137 
138 	return vma;
139 }
140 
141 static void *m_start(struct seq_file *m, loff_t *ppos)
142 {
143 	struct proc_maps_private *priv = m->private;
144 	unsigned long last_addr = *ppos;
145 	struct mm_struct *mm;
146 
147 	/* See m_next(). Zero at the start or after lseek. */
148 	if (last_addr == -1UL)
149 		return NULL;
150 
151 	priv->task = get_proc_task(priv->inode);
152 	if (!priv->task)
153 		return ERR_PTR(-ESRCH);
154 
155 	mm = priv->mm;
156 	if (!mm || !mmget_not_zero(mm)) {
157 		put_task_struct(priv->task);
158 		priv->task = NULL;
159 		return NULL;
160 	}
161 
162 	if (mmap_read_lock_killable(mm)) {
163 		mmput(mm);
164 		put_task_struct(priv->task);
165 		priv->task = NULL;
166 		return ERR_PTR(-EINTR);
167 	}
168 
169 	vma_iter_init(&priv->iter, mm, last_addr);
170 	hold_task_mempolicy(priv);
171 	if (last_addr == -2UL)
172 		return get_gate_vma(mm);
173 
174 	return proc_get_vma(priv, ppos);
175 }
176 
177 static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
178 {
179 	if (*ppos == -2UL) {
180 		*ppos = -1UL;
181 		return NULL;
182 	}
183 	return proc_get_vma(m->private, ppos);
184 }
185 
186 static void m_stop(struct seq_file *m, void *v)
187 {
188 	struct proc_maps_private *priv = m->private;
189 	struct mm_struct *mm = priv->mm;
190 
191 	if (!priv->task)
192 		return;
193 
194 	release_task_mempolicy(priv);
195 	mmap_read_unlock(mm);
196 	mmput(mm);
197 	put_task_struct(priv->task);
198 	priv->task = NULL;
199 }
200 
201 static int proc_maps_open(struct inode *inode, struct file *file,
202 			const struct seq_operations *ops, int psize)
203 {
204 	struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
205 
206 	if (!priv)
207 		return -ENOMEM;
208 
209 	priv->inode = inode;
210 	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
211 	if (IS_ERR(priv->mm)) {
212 		int err = PTR_ERR(priv->mm);
213 
214 		seq_release_private(inode, file);
215 		return err;
216 	}
217 
218 	return 0;
219 }
220 
221 static int proc_map_release(struct inode *inode, struct file *file)
222 {
223 	struct seq_file *seq = file->private_data;
224 	struct proc_maps_private *priv = seq->private;
225 
226 	if (priv->mm)
227 		mmdrop(priv->mm);
228 
229 	return seq_release_private(inode, file);
230 }
231 
232 static int do_maps_open(struct inode *inode, struct file *file,
233 			const struct seq_operations *ops)
234 {
235 	return proc_maps_open(inode, file, ops,
236 				sizeof(struct proc_maps_private));
237 }
238 
239 /*
240  * Indicate if the VMA is a stack for the given task; for
241  * /proc/PID/maps that is the stack of the main task.
242  */
243 static int is_stack(struct vm_area_struct *vma)
244 {
245 	/*
246 	 * We make no effort to guess what a given thread considers to be
247 	 * its "stack".  It's not even well-defined for programs written
248 	 * languages like Go.
249 	 */
250 	return vma->vm_start <= vma->vm_mm->start_stack &&
251 		vma->vm_end >= vma->vm_mm->start_stack;
252 }
253 
254 static void show_vma_header_prefix(struct seq_file *m,
255 				   unsigned long start, unsigned long end,
256 				   vm_flags_t flags, unsigned long long pgoff,
257 				   dev_t dev, unsigned long ino)
258 {
259 	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
260 	seq_put_hex_ll(m, NULL, start, 8);
261 	seq_put_hex_ll(m, "-", end, 8);
262 	seq_putc(m, ' ');
263 	seq_putc(m, flags & VM_READ ? 'r' : '-');
264 	seq_putc(m, flags & VM_WRITE ? 'w' : '-');
265 	seq_putc(m, flags & VM_EXEC ? 'x' : '-');
266 	seq_putc(m, flags & VM_MAYSHARE ? 's' : 'p');
267 	seq_put_hex_ll(m, " ", pgoff, 8);
268 	seq_put_hex_ll(m, " ", MAJOR(dev), 2);
269 	seq_put_hex_ll(m, ":", MINOR(dev), 2);
270 	seq_put_decimal_ull(m, " ", ino);
271 	seq_putc(m, ' ');
272 }
273 
274 static void
275 show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
276 {
277 	struct anon_vma_name *anon_name = NULL;
278 	struct mm_struct *mm = vma->vm_mm;
279 	struct file *file = vma->vm_file;
280 	vm_flags_t flags = vma->vm_flags;
281 	unsigned long ino = 0;
282 	unsigned long long pgoff = 0;
283 	unsigned long start, end;
284 	dev_t dev = 0;
285 	const char *name = NULL;
286 
287 	if (file) {
288 		struct inode *inode = file_inode(vma->vm_file);
289 		dev = inode->i_sb->s_dev;
290 		ino = inode->i_ino;
291 		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
292 	}
293 
294 	start = vma->vm_start;
295 	end = vma->vm_end;
296 	show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
297 	if (mm)
298 		anon_name = anon_vma_name(vma);
299 
300 	/*
301 	 * Print the dentry name for named mappings, and a
302 	 * special [heap] marker for the heap:
303 	 */
304 	if (file) {
305 		seq_pad(m, ' ');
306 		/*
307 		 * If user named this anon shared memory via
308 		 * prctl(PR_SET_VMA ..., use the provided name.
309 		 */
310 		if (anon_name)
311 			seq_printf(m, "[anon_shmem:%s]", anon_name->name);
312 		else
313 			seq_file_path(m, file, "\n");
314 		goto done;
315 	}
316 
317 	if (vma->vm_ops && vma->vm_ops->name) {
318 		name = vma->vm_ops->name(vma);
319 		if (name)
320 			goto done;
321 	}
322 
323 	name = arch_vma_name(vma);
324 	if (!name) {
325 		if (!mm) {
326 			name = "[vdso]";
327 			goto done;
328 		}
329 
330 		if (vma->vm_start <= mm->brk &&
331 		    vma->vm_end >= mm->start_brk) {
332 			name = "[heap]";
333 			goto done;
334 		}
335 
336 		if (is_stack(vma)) {
337 			name = "[stack]";
338 			goto done;
339 		}
340 
341 		if (anon_name) {
342 			seq_pad(m, ' ');
343 			seq_printf(m, "[anon:%s]", anon_name->name);
344 		}
345 	}
346 
347 done:
348 	if (name) {
349 		seq_pad(m, ' ');
350 		seq_puts(m, name);
351 	}
352 	seq_putc(m, '\n');
353 }
354 
355 static int show_map(struct seq_file *m, void *v)
356 {
357 	show_map_vma(m, v);
358 	return 0;
359 }
360 
361 static const struct seq_operations proc_pid_maps_op = {
362 	.start	= m_start,
363 	.next	= m_next,
364 	.stop	= m_stop,
365 	.show	= show_map
366 };
367 
368 static int pid_maps_open(struct inode *inode, struct file *file)
369 {
370 	return do_maps_open(inode, file, &proc_pid_maps_op);
371 }
372 
373 const struct file_operations proc_pid_maps_operations = {
374 	.open		= pid_maps_open,
375 	.read		= seq_read,
376 	.llseek		= seq_lseek,
377 	.release	= proc_map_release,
378 };
379 
380 /*
381  * Proportional Set Size(PSS): my share of RSS.
382  *
383  * PSS of a process is the count of pages it has in memory, where each
384  * page is divided by the number of processes sharing it.  So if a
385  * process has 1000 pages all to itself, and 1000 shared with one other
386  * process, its PSS will be 1500.
387  *
388  * To keep (accumulated) division errors low, we adopt a 64bit
389  * fixed-point pss counter to minimize division errors. So (pss >>
390  * PSS_SHIFT) would be the real byte count.
391  *
392  * A shift of 12 before division means (assuming 4K page size):
393  * 	- 1M 3-user-pages add up to 8KB errors;
394  * 	- supports mapcount up to 2^24, or 16M;
395  * 	- supports PSS up to 2^52 bytes, or 4PB.
396  */
397 #define PSS_SHIFT 12
398 
399 #ifdef CONFIG_PROC_PAGE_MONITOR
400 struct mem_size_stats {
401 	unsigned long resident;
402 	unsigned long shared_clean;
403 	unsigned long shared_dirty;
404 	unsigned long private_clean;
405 	unsigned long private_dirty;
406 	unsigned long referenced;
407 	unsigned long anonymous;
408 	unsigned long lazyfree;
409 	unsigned long anonymous_thp;
410 	unsigned long shmem_thp;
411 	unsigned long file_thp;
412 	unsigned long swap;
413 	unsigned long shared_hugetlb;
414 	unsigned long private_hugetlb;
415 	u64 pss;
416 	u64 pss_anon;
417 	u64 pss_file;
418 	u64 pss_shmem;
419 	u64 pss_dirty;
420 	u64 pss_locked;
421 	u64 swap_pss;
422 };
423 
424 static void smaps_page_accumulate(struct mem_size_stats *mss,
425 		struct page *page, unsigned long size, unsigned long pss,
426 		bool dirty, bool locked, bool private)
427 {
428 	mss->pss += pss;
429 
430 	if (PageAnon(page))
431 		mss->pss_anon += pss;
432 	else if (PageSwapBacked(page))
433 		mss->pss_shmem += pss;
434 	else
435 		mss->pss_file += pss;
436 
437 	if (locked)
438 		mss->pss_locked += pss;
439 
440 	if (dirty || PageDirty(page)) {
441 		mss->pss_dirty += pss;
442 		if (private)
443 			mss->private_dirty += size;
444 		else
445 			mss->shared_dirty += size;
446 	} else {
447 		if (private)
448 			mss->private_clean += size;
449 		else
450 			mss->shared_clean += size;
451 	}
452 }
453 
454 static void smaps_account(struct mem_size_stats *mss, struct page *page,
455 		bool compound, bool young, bool dirty, bool locked,
456 		bool migration)
457 {
458 	int i, nr = compound ? compound_nr(page) : 1;
459 	unsigned long size = nr * PAGE_SIZE;
460 
461 	/*
462 	 * First accumulate quantities that depend only on |size| and the type
463 	 * of the compound page.
464 	 */
465 	if (PageAnon(page)) {
466 		mss->anonymous += size;
467 		if (!PageSwapBacked(page) && !dirty && !PageDirty(page))
468 			mss->lazyfree += size;
469 	}
470 
471 	mss->resident += size;
472 	/* Accumulate the size in pages that have been accessed. */
473 	if (young || page_is_young(page) || PageReferenced(page))
474 		mss->referenced += size;
475 
476 	/*
477 	 * Then accumulate quantities that may depend on sharing, or that may
478 	 * differ page-by-page.
479 	 *
480 	 * page_count(page) == 1 guarantees the page is mapped exactly once.
481 	 * If any subpage of the compound page mapped with PTE it would elevate
482 	 * page_count().
483 	 *
484 	 * The page_mapcount() is called to get a snapshot of the mapcount.
485 	 * Without holding the page lock this snapshot can be slightly wrong as
486 	 * we cannot always read the mapcount atomically.  It is not safe to
487 	 * call page_mapcount() even with PTL held if the page is not mapped,
488 	 * especially for migration entries.  Treat regular migration entries
489 	 * as mapcount == 1.
490 	 */
491 	if ((page_count(page) == 1) || migration) {
492 		smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty,
493 			locked, true);
494 		return;
495 	}
496 	for (i = 0; i < nr; i++, page++) {
497 		int mapcount = page_mapcount(page);
498 		unsigned long pss = PAGE_SIZE << PSS_SHIFT;
499 		if (mapcount >= 2)
500 			pss /= mapcount;
501 		smaps_page_accumulate(mss, page, PAGE_SIZE, pss, dirty, locked,
502 				      mapcount < 2);
503 	}
504 }
505 
506 #ifdef CONFIG_SHMEM
507 static int smaps_pte_hole(unsigned long addr, unsigned long end,
508 			  __always_unused int depth, struct mm_walk *walk)
509 {
510 	struct mem_size_stats *mss = walk->private;
511 	struct vm_area_struct *vma = walk->vma;
512 
513 	mss->swap += shmem_partial_swap_usage(walk->vma->vm_file->f_mapping,
514 					      linear_page_index(vma, addr),
515 					      linear_page_index(vma, end));
516 
517 	return 0;
518 }
519 #else
520 #define smaps_pte_hole		NULL
521 #endif /* CONFIG_SHMEM */
522 
523 static void smaps_pte_hole_lookup(unsigned long addr, struct mm_walk *walk)
524 {
525 #ifdef CONFIG_SHMEM
526 	if (walk->ops->pte_hole) {
527 		/* depth is not used */
528 		smaps_pte_hole(addr, addr + PAGE_SIZE, 0, walk);
529 	}
530 #endif
531 }
532 
533 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
534 		struct mm_walk *walk)
535 {
536 	struct mem_size_stats *mss = walk->private;
537 	struct vm_area_struct *vma = walk->vma;
538 	bool locked = !!(vma->vm_flags & VM_LOCKED);
539 	struct page *page = NULL;
540 	bool migration = false, young = false, dirty = false;
541 	pte_t ptent = ptep_get(pte);
542 
543 	if (pte_present(ptent)) {
544 		page = vm_normal_page(vma, addr, ptent);
545 		young = pte_young(ptent);
546 		dirty = pte_dirty(ptent);
547 	} else if (is_swap_pte(ptent)) {
548 		swp_entry_t swpent = pte_to_swp_entry(ptent);
549 
550 		if (!non_swap_entry(swpent)) {
551 			int mapcount;
552 
553 			mss->swap += PAGE_SIZE;
554 			mapcount = swp_swapcount(swpent);
555 			if (mapcount >= 2) {
556 				u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
557 
558 				do_div(pss_delta, mapcount);
559 				mss->swap_pss += pss_delta;
560 			} else {
561 				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
562 			}
563 		} else if (is_pfn_swap_entry(swpent)) {
564 			if (is_migration_entry(swpent))
565 				migration = true;
566 			page = pfn_swap_entry_to_page(swpent);
567 		}
568 	} else {
569 		smaps_pte_hole_lookup(addr, walk);
570 		return;
571 	}
572 
573 	if (!page)
574 		return;
575 
576 	smaps_account(mss, page, false, young, dirty, locked, migration);
577 }
578 
579 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
580 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
581 		struct mm_walk *walk)
582 {
583 	struct mem_size_stats *mss = walk->private;
584 	struct vm_area_struct *vma = walk->vma;
585 	bool locked = !!(vma->vm_flags & VM_LOCKED);
586 	struct page *page = NULL;
587 	bool migration = false;
588 
589 	if (pmd_present(*pmd)) {
590 		page = vm_normal_page_pmd(vma, addr, *pmd);
591 	} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
592 		swp_entry_t entry = pmd_to_swp_entry(*pmd);
593 
594 		if (is_migration_entry(entry)) {
595 			migration = true;
596 			page = pfn_swap_entry_to_page(entry);
597 		}
598 	}
599 	if (IS_ERR_OR_NULL(page))
600 		return;
601 	if (PageAnon(page))
602 		mss->anonymous_thp += HPAGE_PMD_SIZE;
603 	else if (PageSwapBacked(page))
604 		mss->shmem_thp += HPAGE_PMD_SIZE;
605 	else if (is_zone_device_page(page))
606 		/* pass */;
607 	else
608 		mss->file_thp += HPAGE_PMD_SIZE;
609 
610 	smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd),
611 		      locked, migration);
612 }
613 #else
614 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
615 		struct mm_walk *walk)
616 {
617 }
618 #endif
619 
620 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
621 			   struct mm_walk *walk)
622 {
623 	struct vm_area_struct *vma = walk->vma;
624 	pte_t *pte;
625 	spinlock_t *ptl;
626 
627 	ptl = pmd_trans_huge_lock(pmd, vma);
628 	if (ptl) {
629 		smaps_pmd_entry(pmd, addr, walk);
630 		spin_unlock(ptl);
631 		goto out;
632 	}
633 
634 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
635 	if (!pte) {
636 		walk->action = ACTION_AGAIN;
637 		return 0;
638 	}
639 	for (; addr != end; pte++, addr += PAGE_SIZE)
640 		smaps_pte_entry(pte, addr, walk);
641 	pte_unmap_unlock(pte - 1, ptl);
642 out:
643 	cond_resched();
644 	return 0;
645 }
646 
647 static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
648 {
649 	/*
650 	 * Don't forget to update Documentation/ on changes.
651 	 */
652 	static const char mnemonics[BITS_PER_LONG][2] = {
653 		/*
654 		 * In case if we meet a flag we don't know about.
655 		 */
656 		[0 ... (BITS_PER_LONG-1)] = "??",
657 
658 		[ilog2(VM_READ)]	= "rd",
659 		[ilog2(VM_WRITE)]	= "wr",
660 		[ilog2(VM_EXEC)]	= "ex",
661 		[ilog2(VM_SHARED)]	= "sh",
662 		[ilog2(VM_MAYREAD)]	= "mr",
663 		[ilog2(VM_MAYWRITE)]	= "mw",
664 		[ilog2(VM_MAYEXEC)]	= "me",
665 		[ilog2(VM_MAYSHARE)]	= "ms",
666 		[ilog2(VM_GROWSDOWN)]	= "gd",
667 		[ilog2(VM_PFNMAP)]	= "pf",
668 		[ilog2(VM_LOCKED)]	= "lo",
669 		[ilog2(VM_IO)]		= "io",
670 		[ilog2(VM_SEQ_READ)]	= "sr",
671 		[ilog2(VM_RAND_READ)]	= "rr",
672 		[ilog2(VM_DONTCOPY)]	= "dc",
673 		[ilog2(VM_DONTEXPAND)]	= "de",
674 		[ilog2(VM_LOCKONFAULT)]	= "lf",
675 		[ilog2(VM_ACCOUNT)]	= "ac",
676 		[ilog2(VM_NORESERVE)]	= "nr",
677 		[ilog2(VM_HUGETLB)]	= "ht",
678 		[ilog2(VM_SYNC)]	= "sf",
679 		[ilog2(VM_ARCH_1)]	= "ar",
680 		[ilog2(VM_WIPEONFORK)]	= "wf",
681 		[ilog2(VM_DONTDUMP)]	= "dd",
682 #ifdef CONFIG_ARM64_BTI
683 		[ilog2(VM_ARM64_BTI)]	= "bt",
684 #endif
685 #ifdef CONFIG_MEM_SOFT_DIRTY
686 		[ilog2(VM_SOFTDIRTY)]	= "sd",
687 #endif
688 		[ilog2(VM_MIXEDMAP)]	= "mm",
689 		[ilog2(VM_HUGEPAGE)]	= "hg",
690 		[ilog2(VM_NOHUGEPAGE)]	= "nh",
691 		[ilog2(VM_MERGEABLE)]	= "mg",
692 		[ilog2(VM_UFFD_MISSING)]= "um",
693 		[ilog2(VM_UFFD_WP)]	= "uw",
694 #ifdef CONFIG_ARM64_MTE
695 		[ilog2(VM_MTE)]		= "mt",
696 		[ilog2(VM_MTE_ALLOWED)]	= "",
697 #endif
698 #ifdef CONFIG_ARCH_HAS_PKEYS
699 		/* These come out via ProtectionKey: */
700 		[ilog2(VM_PKEY_BIT0)]	= "",
701 		[ilog2(VM_PKEY_BIT1)]	= "",
702 		[ilog2(VM_PKEY_BIT2)]	= "",
703 		[ilog2(VM_PKEY_BIT3)]	= "",
704 #if VM_PKEY_BIT4
705 		[ilog2(VM_PKEY_BIT4)]	= "",
706 #endif
707 #endif /* CONFIG_ARCH_HAS_PKEYS */
708 #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
709 		[ilog2(VM_UFFD_MINOR)]	= "ui",
710 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
711 	};
712 	size_t i;
713 
714 	seq_puts(m, "VmFlags: ");
715 	for (i = 0; i < BITS_PER_LONG; i++) {
716 		if (!mnemonics[i][0])
717 			continue;
718 		if (vma->vm_flags & (1UL << i)) {
719 			seq_putc(m, mnemonics[i][0]);
720 			seq_putc(m, mnemonics[i][1]);
721 			seq_putc(m, ' ');
722 		}
723 	}
724 	seq_putc(m, '\n');
725 }
726 
727 #ifdef CONFIG_HUGETLB_PAGE
728 static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
729 				 unsigned long addr, unsigned long end,
730 				 struct mm_walk *walk)
731 {
732 	struct mem_size_stats *mss = walk->private;
733 	struct vm_area_struct *vma = walk->vma;
734 	struct page *page = NULL;
735 	pte_t ptent = ptep_get(pte);
736 
737 	if (pte_present(ptent)) {
738 		page = vm_normal_page(vma, addr, ptent);
739 	} else if (is_swap_pte(ptent)) {
740 		swp_entry_t swpent = pte_to_swp_entry(ptent);
741 
742 		if (is_pfn_swap_entry(swpent))
743 			page = pfn_swap_entry_to_page(swpent);
744 	}
745 	if (page) {
746 		if (page_mapcount(page) >= 2 || hugetlb_pmd_shared(pte))
747 			mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
748 		else
749 			mss->private_hugetlb += huge_page_size(hstate_vma(vma));
750 	}
751 	return 0;
752 }
753 #else
754 #define smaps_hugetlb_range	NULL
755 #endif /* HUGETLB_PAGE */
756 
757 static const struct mm_walk_ops smaps_walk_ops = {
758 	.pmd_entry		= smaps_pte_range,
759 	.hugetlb_entry		= smaps_hugetlb_range,
760 	.walk_lock		= PGWALK_RDLOCK,
761 };
762 
763 static const struct mm_walk_ops smaps_shmem_walk_ops = {
764 	.pmd_entry		= smaps_pte_range,
765 	.hugetlb_entry		= smaps_hugetlb_range,
766 	.pte_hole		= smaps_pte_hole,
767 	.walk_lock		= PGWALK_RDLOCK,
768 };
769 
770 /*
771  * Gather mem stats from @vma with the indicated beginning
772  * address @start, and keep them in @mss.
773  *
774  * Use vm_start of @vma as the beginning address if @start is 0.
775  */
776 static void smap_gather_stats(struct vm_area_struct *vma,
777 		struct mem_size_stats *mss, unsigned long start)
778 {
779 	const struct mm_walk_ops *ops = &smaps_walk_ops;
780 
781 	/* Invalid start */
782 	if (start >= vma->vm_end)
783 		return;
784 
785 	if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
786 		/*
787 		 * For shared or readonly shmem mappings we know that all
788 		 * swapped out pages belong to the shmem object, and we can
789 		 * obtain the swap value much more efficiently. For private
790 		 * writable mappings, we might have COW pages that are
791 		 * not affected by the parent swapped out pages of the shmem
792 		 * object, so we have to distinguish them during the page walk.
793 		 * Unless we know that the shmem object (or the part mapped by
794 		 * our VMA) has no swapped out pages at all.
795 		 */
796 		unsigned long shmem_swapped = shmem_swap_usage(vma);
797 
798 		if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
799 					!(vma->vm_flags & VM_WRITE))) {
800 			mss->swap += shmem_swapped;
801 		} else {
802 			ops = &smaps_shmem_walk_ops;
803 		}
804 	}
805 
806 	/* mmap_lock is held in m_start */
807 	if (!start)
808 		walk_page_vma(vma, ops, mss);
809 	else
810 		walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss);
811 }
812 
813 #define SEQ_PUT_DEC(str, val) \
814 		seq_put_decimal_ull_width(m, str, (val) >> 10, 8)
815 
816 /* Show the contents common for smaps and smaps_rollup */
817 static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
818 	bool rollup_mode)
819 {
820 	SEQ_PUT_DEC("Rss:            ", mss->resident);
821 	SEQ_PUT_DEC(" kB\nPss:            ", mss->pss >> PSS_SHIFT);
822 	SEQ_PUT_DEC(" kB\nPss_Dirty:      ", mss->pss_dirty >> PSS_SHIFT);
823 	if (rollup_mode) {
824 		/*
825 		 * These are meaningful only for smaps_rollup, otherwise two of
826 		 * them are zero, and the other one is the same as Pss.
827 		 */
828 		SEQ_PUT_DEC(" kB\nPss_Anon:       ",
829 			mss->pss_anon >> PSS_SHIFT);
830 		SEQ_PUT_DEC(" kB\nPss_File:       ",
831 			mss->pss_file >> PSS_SHIFT);
832 		SEQ_PUT_DEC(" kB\nPss_Shmem:      ",
833 			mss->pss_shmem >> PSS_SHIFT);
834 	}
835 	SEQ_PUT_DEC(" kB\nShared_Clean:   ", mss->shared_clean);
836 	SEQ_PUT_DEC(" kB\nShared_Dirty:   ", mss->shared_dirty);
837 	SEQ_PUT_DEC(" kB\nPrivate_Clean:  ", mss->private_clean);
838 	SEQ_PUT_DEC(" kB\nPrivate_Dirty:  ", mss->private_dirty);
839 	SEQ_PUT_DEC(" kB\nReferenced:     ", mss->referenced);
840 	SEQ_PUT_DEC(" kB\nAnonymous:      ", mss->anonymous);
841 	SEQ_PUT_DEC(" kB\nLazyFree:       ", mss->lazyfree);
842 	SEQ_PUT_DEC(" kB\nAnonHugePages:  ", mss->anonymous_thp);
843 	SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
844 	SEQ_PUT_DEC(" kB\nFilePmdMapped:  ", mss->file_thp);
845 	SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
846 	seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
847 				  mss->private_hugetlb >> 10, 7);
848 	SEQ_PUT_DEC(" kB\nSwap:           ", mss->swap);
849 	SEQ_PUT_DEC(" kB\nSwapPss:        ",
850 					mss->swap_pss >> PSS_SHIFT);
851 	SEQ_PUT_DEC(" kB\nLocked:         ",
852 					mss->pss_locked >> PSS_SHIFT);
853 	seq_puts(m, " kB\n");
854 }
855 
856 static int show_smap(struct seq_file *m, void *v)
857 {
858 	struct vm_area_struct *vma = v;
859 	struct mem_size_stats mss;
860 
861 	memset(&mss, 0, sizeof(mss));
862 
863 	smap_gather_stats(vma, &mss, 0);
864 
865 	show_map_vma(m, vma);
866 
867 	SEQ_PUT_DEC("Size:           ", vma->vm_end - vma->vm_start);
868 	SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
869 	SEQ_PUT_DEC(" kB\nMMUPageSize:    ", vma_mmu_pagesize(vma));
870 	seq_puts(m, " kB\n");
871 
872 	__show_smap(m, &mss, false);
873 
874 	seq_printf(m, "THPeligible:    %d\n",
875 		   hugepage_vma_check(vma, vma->vm_flags, true, false, true));
876 
877 	if (arch_pkeys_enabled())
878 		seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
879 	show_smap_vma_flags(m, vma);
880 
881 	return 0;
882 }
883 
884 static int show_smaps_rollup(struct seq_file *m, void *v)
885 {
886 	struct proc_maps_private *priv = m->private;
887 	struct mem_size_stats mss;
888 	struct mm_struct *mm = priv->mm;
889 	struct vm_area_struct *vma;
890 	unsigned long vma_start = 0, last_vma_end = 0;
891 	int ret = 0;
892 	VMA_ITERATOR(vmi, mm, 0);
893 
894 	priv->task = get_proc_task(priv->inode);
895 	if (!priv->task)
896 		return -ESRCH;
897 
898 	if (!mm || !mmget_not_zero(mm)) {
899 		ret = -ESRCH;
900 		goto out_put_task;
901 	}
902 
903 	memset(&mss, 0, sizeof(mss));
904 
905 	ret = mmap_read_lock_killable(mm);
906 	if (ret)
907 		goto out_put_mm;
908 
909 	hold_task_mempolicy(priv);
910 	vma = vma_next(&vmi);
911 
912 	if (unlikely(!vma))
913 		goto empty_set;
914 
915 	vma_start = vma->vm_start;
916 	do {
917 		smap_gather_stats(vma, &mss, 0);
918 		last_vma_end = vma->vm_end;
919 
920 		/*
921 		 * Release mmap_lock temporarily if someone wants to
922 		 * access it for write request.
923 		 */
924 		if (mmap_lock_is_contended(mm)) {
925 			vma_iter_invalidate(&vmi);
926 			mmap_read_unlock(mm);
927 			ret = mmap_read_lock_killable(mm);
928 			if (ret) {
929 				release_task_mempolicy(priv);
930 				goto out_put_mm;
931 			}
932 
933 			/*
934 			 * After dropping the lock, there are four cases to
935 			 * consider. See the following example for explanation.
936 			 *
937 			 *   +------+------+-----------+
938 			 *   | VMA1 | VMA2 | VMA3      |
939 			 *   +------+------+-----------+
940 			 *   |      |      |           |
941 			 *  4k     8k     16k         400k
942 			 *
943 			 * Suppose we drop the lock after reading VMA2 due to
944 			 * contention, then we get:
945 			 *
946 			 *	last_vma_end = 16k
947 			 *
948 			 * 1) VMA2 is freed, but VMA3 exists:
949 			 *
950 			 *    vma_next(vmi) will return VMA3.
951 			 *    In this case, just continue from VMA3.
952 			 *
953 			 * 2) VMA2 still exists:
954 			 *
955 			 *    vma_next(vmi) will return VMA3.
956 			 *    In this case, just continue from VMA3.
957 			 *
958 			 * 3) No more VMAs can be found:
959 			 *
960 			 *    vma_next(vmi) will return NULL.
961 			 *    No more things to do, just break.
962 			 *
963 			 * 4) (last_vma_end - 1) is the middle of a vma (VMA'):
964 			 *
965 			 *    vma_next(vmi) will return VMA' whose range
966 			 *    contains last_vma_end.
967 			 *    Iterate VMA' from last_vma_end.
968 			 */
969 			vma = vma_next(&vmi);
970 			/* Case 3 above */
971 			if (!vma)
972 				break;
973 
974 			/* Case 1 and 2 above */
975 			if (vma->vm_start >= last_vma_end)
976 				continue;
977 
978 			/* Case 4 above */
979 			if (vma->vm_end > last_vma_end)
980 				smap_gather_stats(vma, &mss, last_vma_end);
981 		}
982 	} for_each_vma(vmi, vma);
983 
984 empty_set:
985 	show_vma_header_prefix(m, vma_start, last_vma_end, 0, 0, 0, 0);
986 	seq_pad(m, ' ');
987 	seq_puts(m, "[rollup]\n");
988 
989 	__show_smap(m, &mss, true);
990 
991 	release_task_mempolicy(priv);
992 	mmap_read_unlock(mm);
993 
994 out_put_mm:
995 	mmput(mm);
996 out_put_task:
997 	put_task_struct(priv->task);
998 	priv->task = NULL;
999 
1000 	return ret;
1001 }
1002 #undef SEQ_PUT_DEC
1003 
1004 static const struct seq_operations proc_pid_smaps_op = {
1005 	.start	= m_start,
1006 	.next	= m_next,
1007 	.stop	= m_stop,
1008 	.show	= show_smap
1009 };
1010 
1011 static int pid_smaps_open(struct inode *inode, struct file *file)
1012 {
1013 	return do_maps_open(inode, file, &proc_pid_smaps_op);
1014 }
1015 
1016 static int smaps_rollup_open(struct inode *inode, struct file *file)
1017 {
1018 	int ret;
1019 	struct proc_maps_private *priv;
1020 
1021 	priv = kzalloc(sizeof(*priv), GFP_KERNEL_ACCOUNT);
1022 	if (!priv)
1023 		return -ENOMEM;
1024 
1025 	ret = single_open(file, show_smaps_rollup, priv);
1026 	if (ret)
1027 		goto out_free;
1028 
1029 	priv->inode = inode;
1030 	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
1031 	if (IS_ERR(priv->mm)) {
1032 		ret = PTR_ERR(priv->mm);
1033 
1034 		single_release(inode, file);
1035 		goto out_free;
1036 	}
1037 
1038 	return 0;
1039 
1040 out_free:
1041 	kfree(priv);
1042 	return ret;
1043 }
1044 
1045 static int smaps_rollup_release(struct inode *inode, struct file *file)
1046 {
1047 	struct seq_file *seq = file->private_data;
1048 	struct proc_maps_private *priv = seq->private;
1049 
1050 	if (priv->mm)
1051 		mmdrop(priv->mm);
1052 
1053 	kfree(priv);
1054 	return single_release(inode, file);
1055 }
1056 
1057 const struct file_operations proc_pid_smaps_operations = {
1058 	.open		= pid_smaps_open,
1059 	.read		= seq_read,
1060 	.llseek		= seq_lseek,
1061 	.release	= proc_map_release,
1062 };
1063 
1064 const struct file_operations proc_pid_smaps_rollup_operations = {
1065 	.open		= smaps_rollup_open,
1066 	.read		= seq_read,
1067 	.llseek		= seq_lseek,
1068 	.release	= smaps_rollup_release,
1069 };
1070 
1071 enum clear_refs_types {
1072 	CLEAR_REFS_ALL = 1,
1073 	CLEAR_REFS_ANON,
1074 	CLEAR_REFS_MAPPED,
1075 	CLEAR_REFS_SOFT_DIRTY,
1076 	CLEAR_REFS_MM_HIWATER_RSS,
1077 	CLEAR_REFS_LAST,
1078 };
1079 
1080 struct clear_refs_private {
1081 	enum clear_refs_types type;
1082 };
1083 
1084 #ifdef CONFIG_MEM_SOFT_DIRTY
1085 
1086 static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1087 {
1088 	struct page *page;
1089 
1090 	if (!pte_write(pte))
1091 		return false;
1092 	if (!is_cow_mapping(vma->vm_flags))
1093 		return false;
1094 	if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)))
1095 		return false;
1096 	page = vm_normal_page(vma, addr, pte);
1097 	if (!page)
1098 		return false;
1099 	return page_maybe_dma_pinned(page);
1100 }
1101 
1102 static inline void clear_soft_dirty(struct vm_area_struct *vma,
1103 		unsigned long addr, pte_t *pte)
1104 {
1105 	/*
1106 	 * The soft-dirty tracker uses #PF-s to catch writes
1107 	 * to pages, so write-protect the pte as well. See the
1108 	 * Documentation/admin-guide/mm/soft-dirty.rst for full description
1109 	 * of how soft-dirty works.
1110 	 */
1111 	pte_t ptent = ptep_get(pte);
1112 
1113 	if (pte_present(ptent)) {
1114 		pte_t old_pte;
1115 
1116 		if (pte_is_pinned(vma, addr, ptent))
1117 			return;
1118 		old_pte = ptep_modify_prot_start(vma, addr, pte);
1119 		ptent = pte_wrprotect(old_pte);
1120 		ptent = pte_clear_soft_dirty(ptent);
1121 		ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
1122 	} else if (is_swap_pte(ptent)) {
1123 		ptent = pte_swp_clear_soft_dirty(ptent);
1124 		set_pte_at(vma->vm_mm, addr, pte, ptent);
1125 	}
1126 }
1127 #else
1128 static inline void clear_soft_dirty(struct vm_area_struct *vma,
1129 		unsigned long addr, pte_t *pte)
1130 {
1131 }
1132 #endif
1133 
1134 #if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
1135 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
1136 		unsigned long addr, pmd_t *pmdp)
1137 {
1138 	pmd_t old, pmd = *pmdp;
1139 
1140 	if (pmd_present(pmd)) {
1141 		/* See comment in change_huge_pmd() */
1142 		old = pmdp_invalidate(vma, addr, pmdp);
1143 		if (pmd_dirty(old))
1144 			pmd = pmd_mkdirty(pmd);
1145 		if (pmd_young(old))
1146 			pmd = pmd_mkyoung(pmd);
1147 
1148 		pmd = pmd_wrprotect(pmd);
1149 		pmd = pmd_clear_soft_dirty(pmd);
1150 
1151 		set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
1152 	} else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
1153 		pmd = pmd_swp_clear_soft_dirty(pmd);
1154 		set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
1155 	}
1156 }
1157 #else
1158 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
1159 		unsigned long addr, pmd_t *pmdp)
1160 {
1161 }
1162 #endif
1163 
1164 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
1165 				unsigned long end, struct mm_walk *walk)
1166 {
1167 	struct clear_refs_private *cp = walk->private;
1168 	struct vm_area_struct *vma = walk->vma;
1169 	pte_t *pte, ptent;
1170 	spinlock_t *ptl;
1171 	struct page *page;
1172 
1173 	ptl = pmd_trans_huge_lock(pmd, vma);
1174 	if (ptl) {
1175 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
1176 			clear_soft_dirty_pmd(vma, addr, pmd);
1177 			goto out;
1178 		}
1179 
1180 		if (!pmd_present(*pmd))
1181 			goto out;
1182 
1183 		page = pmd_page(*pmd);
1184 
1185 		/* Clear accessed and referenced bits. */
1186 		pmdp_test_and_clear_young(vma, addr, pmd);
1187 		test_and_clear_page_young(page);
1188 		ClearPageReferenced(page);
1189 out:
1190 		spin_unlock(ptl);
1191 		return 0;
1192 	}
1193 
1194 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
1195 	if (!pte) {
1196 		walk->action = ACTION_AGAIN;
1197 		return 0;
1198 	}
1199 	for (; addr != end; pte++, addr += PAGE_SIZE) {
1200 		ptent = ptep_get(pte);
1201 
1202 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
1203 			clear_soft_dirty(vma, addr, pte);
1204 			continue;
1205 		}
1206 
1207 		if (!pte_present(ptent))
1208 			continue;
1209 
1210 		page = vm_normal_page(vma, addr, ptent);
1211 		if (!page)
1212 			continue;
1213 
1214 		/* Clear accessed and referenced bits. */
1215 		ptep_test_and_clear_young(vma, addr, pte);
1216 		test_and_clear_page_young(page);
1217 		ClearPageReferenced(page);
1218 	}
1219 	pte_unmap_unlock(pte - 1, ptl);
1220 	cond_resched();
1221 	return 0;
1222 }
1223 
1224 static int clear_refs_test_walk(unsigned long start, unsigned long end,
1225 				struct mm_walk *walk)
1226 {
1227 	struct clear_refs_private *cp = walk->private;
1228 	struct vm_area_struct *vma = walk->vma;
1229 
1230 	if (vma->vm_flags & VM_PFNMAP)
1231 		return 1;
1232 
1233 	/*
1234 	 * Writing 1 to /proc/pid/clear_refs affects all pages.
1235 	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
1236 	 * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
1237 	 * Writing 4 to /proc/pid/clear_refs affects all pages.
1238 	 */
1239 	if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
1240 		return 1;
1241 	if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
1242 		return 1;
1243 	return 0;
1244 }
1245 
1246 static const struct mm_walk_ops clear_refs_walk_ops = {
1247 	.pmd_entry		= clear_refs_pte_range,
1248 	.test_walk		= clear_refs_test_walk,
1249 	.walk_lock		= PGWALK_WRLOCK,
1250 };
1251 
1252 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
1253 				size_t count, loff_t *ppos)
1254 {
1255 	struct task_struct *task;
1256 	char buffer[PROC_NUMBUF];
1257 	struct mm_struct *mm;
1258 	struct vm_area_struct *vma;
1259 	enum clear_refs_types type;
1260 	int itype;
1261 	int rv;
1262 
1263 	memset(buffer, 0, sizeof(buffer));
1264 	if (count > sizeof(buffer) - 1)
1265 		count = sizeof(buffer) - 1;
1266 	if (copy_from_user(buffer, buf, count))
1267 		return -EFAULT;
1268 	rv = kstrtoint(strstrip(buffer), 10, &itype);
1269 	if (rv < 0)
1270 		return rv;
1271 	type = (enum clear_refs_types)itype;
1272 	if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
1273 		return -EINVAL;
1274 
1275 	task = get_proc_task(file_inode(file));
1276 	if (!task)
1277 		return -ESRCH;
1278 	mm = get_task_mm(task);
1279 	if (mm) {
1280 		VMA_ITERATOR(vmi, mm, 0);
1281 		struct mmu_notifier_range range;
1282 		struct clear_refs_private cp = {
1283 			.type = type,
1284 		};
1285 
1286 		if (mmap_write_lock_killable(mm)) {
1287 			count = -EINTR;
1288 			goto out_mm;
1289 		}
1290 		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
1291 			/*
1292 			 * Writing 5 to /proc/pid/clear_refs resets the peak
1293 			 * resident set size to this mm's current rss value.
1294 			 */
1295 			reset_mm_hiwater_rss(mm);
1296 			goto out_unlock;
1297 		}
1298 
1299 		if (type == CLEAR_REFS_SOFT_DIRTY) {
1300 			for_each_vma(vmi, vma) {
1301 				if (!(vma->vm_flags & VM_SOFTDIRTY))
1302 					continue;
1303 				vm_flags_clear(vma, VM_SOFTDIRTY);
1304 				vma_set_page_prot(vma);
1305 			}
1306 
1307 			inc_tlb_flush_pending(mm);
1308 			mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
1309 						0, mm, 0, -1UL);
1310 			mmu_notifier_invalidate_range_start(&range);
1311 		}
1312 		walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp);
1313 		if (type == CLEAR_REFS_SOFT_DIRTY) {
1314 			mmu_notifier_invalidate_range_end(&range);
1315 			flush_tlb_mm(mm);
1316 			dec_tlb_flush_pending(mm);
1317 		}
1318 out_unlock:
1319 		mmap_write_unlock(mm);
1320 out_mm:
1321 		mmput(mm);
1322 	}
1323 	put_task_struct(task);
1324 
1325 	return count;
1326 }
1327 
1328 const struct file_operations proc_clear_refs_operations = {
1329 	.write		= clear_refs_write,
1330 	.llseek		= noop_llseek,
1331 };
1332 
1333 typedef struct {
1334 	u64 pme;
1335 } pagemap_entry_t;
1336 
1337 struct pagemapread {
1338 	int pos, len;		/* units: PM_ENTRY_BYTES, not bytes */
1339 	pagemap_entry_t *buffer;
1340 	bool show_pfn;
1341 };
1342 
1343 #define PAGEMAP_WALK_SIZE	(PMD_SIZE)
1344 #define PAGEMAP_WALK_MASK	(PMD_MASK)
1345 
1346 #define PM_ENTRY_BYTES		sizeof(pagemap_entry_t)
1347 #define PM_PFRAME_BITS		55
1348 #define PM_PFRAME_MASK		GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
1349 #define PM_SOFT_DIRTY		BIT_ULL(55)
1350 #define PM_MMAP_EXCLUSIVE	BIT_ULL(56)
1351 #define PM_UFFD_WP		BIT_ULL(57)
1352 #define PM_FILE			BIT_ULL(61)
1353 #define PM_SWAP			BIT_ULL(62)
1354 #define PM_PRESENT		BIT_ULL(63)
1355 
1356 #define PM_END_OF_BUFFER    1
1357 
1358 static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
1359 {
1360 	return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
1361 }
1362 
1363 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
1364 			  struct pagemapread *pm)
1365 {
1366 	pm->buffer[pm->pos++] = *pme;
1367 	if (pm->pos >= pm->len)
1368 		return PM_END_OF_BUFFER;
1369 	return 0;
1370 }
1371 
1372 static int pagemap_pte_hole(unsigned long start, unsigned long end,
1373 			    __always_unused int depth, struct mm_walk *walk)
1374 {
1375 	struct pagemapread *pm = walk->private;
1376 	unsigned long addr = start;
1377 	int err = 0;
1378 
1379 	while (addr < end) {
1380 		struct vm_area_struct *vma = find_vma(walk->mm, addr);
1381 		pagemap_entry_t pme = make_pme(0, 0);
1382 		/* End of address space hole, which we mark as non-present. */
1383 		unsigned long hole_end;
1384 
1385 		if (vma)
1386 			hole_end = min(end, vma->vm_start);
1387 		else
1388 			hole_end = end;
1389 
1390 		for (; addr < hole_end; addr += PAGE_SIZE) {
1391 			err = add_to_pagemap(addr, &pme, pm);
1392 			if (err)
1393 				goto out;
1394 		}
1395 
1396 		if (!vma)
1397 			break;
1398 
1399 		/* Addresses in the VMA. */
1400 		if (vma->vm_flags & VM_SOFTDIRTY)
1401 			pme = make_pme(0, PM_SOFT_DIRTY);
1402 		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
1403 			err = add_to_pagemap(addr, &pme, pm);
1404 			if (err)
1405 				goto out;
1406 		}
1407 	}
1408 out:
1409 	return err;
1410 }
1411 
1412 static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
1413 		struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1414 {
1415 	u64 frame = 0, flags = 0;
1416 	struct page *page = NULL;
1417 	bool migration = false;
1418 
1419 	if (pte_present(pte)) {
1420 		if (pm->show_pfn)
1421 			frame = pte_pfn(pte);
1422 		flags |= PM_PRESENT;
1423 		page = vm_normal_page(vma, addr, pte);
1424 		if (pte_soft_dirty(pte))
1425 			flags |= PM_SOFT_DIRTY;
1426 		if (pte_uffd_wp(pte))
1427 			flags |= PM_UFFD_WP;
1428 	} else if (is_swap_pte(pte)) {
1429 		swp_entry_t entry;
1430 		if (pte_swp_soft_dirty(pte))
1431 			flags |= PM_SOFT_DIRTY;
1432 		if (pte_swp_uffd_wp(pte))
1433 			flags |= PM_UFFD_WP;
1434 		entry = pte_to_swp_entry(pte);
1435 		if (pm->show_pfn) {
1436 			pgoff_t offset;
1437 			/*
1438 			 * For PFN swap offsets, keeping the offset field
1439 			 * to be PFN only to be compatible with old smaps.
1440 			 */
1441 			if (is_pfn_swap_entry(entry))
1442 				offset = swp_offset_pfn(entry);
1443 			else
1444 				offset = swp_offset(entry);
1445 			frame = swp_type(entry) |
1446 			    (offset << MAX_SWAPFILES_SHIFT);
1447 		}
1448 		flags |= PM_SWAP;
1449 		migration = is_migration_entry(entry);
1450 		if (is_pfn_swap_entry(entry))
1451 			page = pfn_swap_entry_to_page(entry);
1452 		if (pte_marker_entry_uffd_wp(entry))
1453 			flags |= PM_UFFD_WP;
1454 	}
1455 
1456 	if (page && !PageAnon(page))
1457 		flags |= PM_FILE;
1458 	if (page && !migration && page_mapcount(page) == 1)
1459 		flags |= PM_MMAP_EXCLUSIVE;
1460 	if (vma->vm_flags & VM_SOFTDIRTY)
1461 		flags |= PM_SOFT_DIRTY;
1462 
1463 	return make_pme(frame, flags);
1464 }
1465 
1466 static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
1467 			     struct mm_walk *walk)
1468 {
1469 	struct vm_area_struct *vma = walk->vma;
1470 	struct pagemapread *pm = walk->private;
1471 	spinlock_t *ptl;
1472 	pte_t *pte, *orig_pte;
1473 	int err = 0;
1474 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1475 	bool migration = false;
1476 
1477 	ptl = pmd_trans_huge_lock(pmdp, vma);
1478 	if (ptl) {
1479 		u64 flags = 0, frame = 0;
1480 		pmd_t pmd = *pmdp;
1481 		struct page *page = NULL;
1482 
1483 		if (vma->vm_flags & VM_SOFTDIRTY)
1484 			flags |= PM_SOFT_DIRTY;
1485 
1486 		if (pmd_present(pmd)) {
1487 			page = pmd_page(pmd);
1488 
1489 			flags |= PM_PRESENT;
1490 			if (pmd_soft_dirty(pmd))
1491 				flags |= PM_SOFT_DIRTY;
1492 			if (pmd_uffd_wp(pmd))
1493 				flags |= PM_UFFD_WP;
1494 			if (pm->show_pfn)
1495 				frame = pmd_pfn(pmd) +
1496 					((addr & ~PMD_MASK) >> PAGE_SHIFT);
1497 		}
1498 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1499 		else if (is_swap_pmd(pmd)) {
1500 			swp_entry_t entry = pmd_to_swp_entry(pmd);
1501 			unsigned long offset;
1502 
1503 			if (pm->show_pfn) {
1504 				if (is_pfn_swap_entry(entry))
1505 					offset = swp_offset_pfn(entry);
1506 				else
1507 					offset = swp_offset(entry);
1508 				offset = offset +
1509 					((addr & ~PMD_MASK) >> PAGE_SHIFT);
1510 				frame = swp_type(entry) |
1511 					(offset << MAX_SWAPFILES_SHIFT);
1512 			}
1513 			flags |= PM_SWAP;
1514 			if (pmd_swp_soft_dirty(pmd))
1515 				flags |= PM_SOFT_DIRTY;
1516 			if (pmd_swp_uffd_wp(pmd))
1517 				flags |= PM_UFFD_WP;
1518 			VM_BUG_ON(!is_pmd_migration_entry(pmd));
1519 			migration = is_migration_entry(entry);
1520 			page = pfn_swap_entry_to_page(entry);
1521 		}
1522 #endif
1523 
1524 		if (page && !migration && page_mapcount(page) == 1)
1525 			flags |= PM_MMAP_EXCLUSIVE;
1526 
1527 		for (; addr != end; addr += PAGE_SIZE) {
1528 			pagemap_entry_t pme = make_pme(frame, flags);
1529 
1530 			err = add_to_pagemap(addr, &pme, pm);
1531 			if (err)
1532 				break;
1533 			if (pm->show_pfn) {
1534 				if (flags & PM_PRESENT)
1535 					frame++;
1536 				else if (flags & PM_SWAP)
1537 					frame += (1 << MAX_SWAPFILES_SHIFT);
1538 			}
1539 		}
1540 		spin_unlock(ptl);
1541 		return err;
1542 	}
1543 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1544 
1545 	/*
1546 	 * We can assume that @vma always points to a valid one and @end never
1547 	 * goes beyond vma->vm_end.
1548 	 */
1549 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
1550 	if (!pte) {
1551 		walk->action = ACTION_AGAIN;
1552 		return err;
1553 	}
1554 	for (; addr < end; pte++, addr += PAGE_SIZE) {
1555 		pagemap_entry_t pme;
1556 
1557 		pme = pte_to_pagemap_entry(pm, vma, addr, ptep_get(pte));
1558 		err = add_to_pagemap(addr, &pme, pm);
1559 		if (err)
1560 			break;
1561 	}
1562 	pte_unmap_unlock(orig_pte, ptl);
1563 
1564 	cond_resched();
1565 
1566 	return err;
1567 }
1568 
1569 #ifdef CONFIG_HUGETLB_PAGE
1570 /* This function walks within one hugetlb entry in the single call */
1571 static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
1572 				 unsigned long addr, unsigned long end,
1573 				 struct mm_walk *walk)
1574 {
1575 	struct pagemapread *pm = walk->private;
1576 	struct vm_area_struct *vma = walk->vma;
1577 	u64 flags = 0, frame = 0;
1578 	int err = 0;
1579 	pte_t pte;
1580 
1581 	if (vma->vm_flags & VM_SOFTDIRTY)
1582 		flags |= PM_SOFT_DIRTY;
1583 
1584 	pte = huge_ptep_get(ptep);
1585 	if (pte_present(pte)) {
1586 		struct page *page = pte_page(pte);
1587 
1588 		if (!PageAnon(page))
1589 			flags |= PM_FILE;
1590 
1591 		if (page_mapcount(page) == 1)
1592 			flags |= PM_MMAP_EXCLUSIVE;
1593 
1594 		if (huge_pte_uffd_wp(pte))
1595 			flags |= PM_UFFD_WP;
1596 
1597 		flags |= PM_PRESENT;
1598 		if (pm->show_pfn)
1599 			frame = pte_pfn(pte) +
1600 				((addr & ~hmask) >> PAGE_SHIFT);
1601 	} else if (pte_swp_uffd_wp_any(pte)) {
1602 		flags |= PM_UFFD_WP;
1603 	}
1604 
1605 	for (; addr != end; addr += PAGE_SIZE) {
1606 		pagemap_entry_t pme = make_pme(frame, flags);
1607 
1608 		err = add_to_pagemap(addr, &pme, pm);
1609 		if (err)
1610 			return err;
1611 		if (pm->show_pfn && (flags & PM_PRESENT))
1612 			frame++;
1613 	}
1614 
1615 	cond_resched();
1616 
1617 	return err;
1618 }
1619 #else
1620 #define pagemap_hugetlb_range	NULL
1621 #endif /* HUGETLB_PAGE */
1622 
1623 static const struct mm_walk_ops pagemap_ops = {
1624 	.pmd_entry	= pagemap_pmd_range,
1625 	.pte_hole	= pagemap_pte_hole,
1626 	.hugetlb_entry	= pagemap_hugetlb_range,
1627 	.walk_lock	= PGWALK_RDLOCK,
1628 };
1629 
1630 /*
1631  * /proc/pid/pagemap - an array mapping virtual pages to pfns
1632  *
1633  * For each page in the address space, this file contains one 64-bit entry
1634  * consisting of the following:
1635  *
1636  * Bits 0-54  page frame number (PFN) if present
1637  * Bits 0-4   swap type if swapped
1638  * Bits 5-54  swap offset if swapped
1639  * Bit  55    pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)
1640  * Bit  56    page exclusively mapped
1641  * Bit  57    pte is uffd-wp write-protected
1642  * Bits 58-60 zero
1643  * Bit  61    page is file-page or shared-anon
1644  * Bit  62    page swapped
1645  * Bit  63    page present
1646  *
1647  * If the page is not present but in swap, then the PFN contains an
1648  * encoding of the swap file number and the page's offset into the
1649  * swap. Unmapped pages return a null PFN. This allows determining
1650  * precisely which pages are mapped (or in swap) and comparing mapped
1651  * pages between processes.
1652  *
1653  * Efficient users of this interface will use /proc/pid/maps to
1654  * determine which areas of memory are actually mapped and llseek to
1655  * skip over unmapped regions.
1656  */
1657 static ssize_t pagemap_read(struct file *file, char __user *buf,
1658 			    size_t count, loff_t *ppos)
1659 {
1660 	struct mm_struct *mm = file->private_data;
1661 	struct pagemapread pm;
1662 	unsigned long src;
1663 	unsigned long svpfn;
1664 	unsigned long start_vaddr;
1665 	unsigned long end_vaddr;
1666 	int ret = 0, copied = 0;
1667 
1668 	if (!mm || !mmget_not_zero(mm))
1669 		goto out;
1670 
1671 	ret = -EINVAL;
1672 	/* file position must be aligned */
1673 	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
1674 		goto out_mm;
1675 
1676 	ret = 0;
1677 	if (!count)
1678 		goto out_mm;
1679 
1680 	/* do not disclose physical addresses: attack vector */
1681 	pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
1682 
1683 	pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
1684 	pm.buffer = kmalloc_array(pm.len, PM_ENTRY_BYTES, GFP_KERNEL);
1685 	ret = -ENOMEM;
1686 	if (!pm.buffer)
1687 		goto out_mm;
1688 
1689 	src = *ppos;
1690 	svpfn = src / PM_ENTRY_BYTES;
1691 	end_vaddr = mm->task_size;
1692 
1693 	/* watch out for wraparound */
1694 	start_vaddr = end_vaddr;
1695 	if (svpfn <= (ULONG_MAX >> PAGE_SHIFT)) {
1696 		unsigned long end;
1697 
1698 		ret = mmap_read_lock_killable(mm);
1699 		if (ret)
1700 			goto out_free;
1701 		start_vaddr = untagged_addr_remote(mm, svpfn << PAGE_SHIFT);
1702 		mmap_read_unlock(mm);
1703 
1704 		end = start_vaddr + ((count / PM_ENTRY_BYTES) << PAGE_SHIFT);
1705 		if (end >= start_vaddr && end < mm->task_size)
1706 			end_vaddr = end;
1707 	}
1708 
1709 	/* Ensure the address is inside the task */
1710 	if (start_vaddr > mm->task_size)
1711 		start_vaddr = end_vaddr;
1712 
1713 	ret = 0;
1714 	while (count && (start_vaddr < end_vaddr)) {
1715 		int len;
1716 		unsigned long end;
1717 
1718 		pm.pos = 0;
1719 		end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
1720 		/* overflow ? */
1721 		if (end < start_vaddr || end > end_vaddr)
1722 			end = end_vaddr;
1723 		ret = mmap_read_lock_killable(mm);
1724 		if (ret)
1725 			goto out_free;
1726 		ret = walk_page_range(mm, start_vaddr, end, &pagemap_ops, &pm);
1727 		mmap_read_unlock(mm);
1728 		start_vaddr = end;
1729 
1730 		len = min(count, PM_ENTRY_BYTES * pm.pos);
1731 		if (copy_to_user(buf, pm.buffer, len)) {
1732 			ret = -EFAULT;
1733 			goto out_free;
1734 		}
1735 		copied += len;
1736 		buf += len;
1737 		count -= len;
1738 	}
1739 	*ppos += copied;
1740 	if (!ret || ret == PM_END_OF_BUFFER)
1741 		ret = copied;
1742 
1743 out_free:
1744 	kfree(pm.buffer);
1745 out_mm:
1746 	mmput(mm);
1747 out:
1748 	return ret;
1749 }
1750 
1751 static int pagemap_open(struct inode *inode, struct file *file)
1752 {
1753 	struct mm_struct *mm;
1754 
1755 	mm = proc_mem_open(inode, PTRACE_MODE_READ);
1756 	if (IS_ERR(mm))
1757 		return PTR_ERR(mm);
1758 	file->private_data = mm;
1759 	return 0;
1760 }
1761 
1762 static int pagemap_release(struct inode *inode, struct file *file)
1763 {
1764 	struct mm_struct *mm = file->private_data;
1765 
1766 	if (mm)
1767 		mmdrop(mm);
1768 	return 0;
1769 }
1770 
1771 const struct file_operations proc_pagemap_operations = {
1772 	.llseek		= mem_lseek, /* borrow this */
1773 	.read		= pagemap_read,
1774 	.open		= pagemap_open,
1775 	.release	= pagemap_release,
1776 };
1777 #endif /* CONFIG_PROC_PAGE_MONITOR */
1778 
1779 #ifdef CONFIG_NUMA
1780 
1781 struct numa_maps {
1782 	unsigned long pages;
1783 	unsigned long anon;
1784 	unsigned long active;
1785 	unsigned long writeback;
1786 	unsigned long mapcount_max;
1787 	unsigned long dirty;
1788 	unsigned long swapcache;
1789 	unsigned long node[MAX_NUMNODES];
1790 };
1791 
1792 struct numa_maps_private {
1793 	struct proc_maps_private proc_maps;
1794 	struct numa_maps md;
1795 };
1796 
1797 static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
1798 			unsigned long nr_pages)
1799 {
1800 	int count = page_mapcount(page);
1801 
1802 	md->pages += nr_pages;
1803 	if (pte_dirty || PageDirty(page))
1804 		md->dirty += nr_pages;
1805 
1806 	if (PageSwapCache(page))
1807 		md->swapcache += nr_pages;
1808 
1809 	if (PageActive(page) || PageUnevictable(page))
1810 		md->active += nr_pages;
1811 
1812 	if (PageWriteback(page))
1813 		md->writeback += nr_pages;
1814 
1815 	if (PageAnon(page))
1816 		md->anon += nr_pages;
1817 
1818 	if (count > md->mapcount_max)
1819 		md->mapcount_max = count;
1820 
1821 	md->node[page_to_nid(page)] += nr_pages;
1822 }
1823 
1824 static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
1825 		unsigned long addr)
1826 {
1827 	struct page *page;
1828 	int nid;
1829 
1830 	if (!pte_present(pte))
1831 		return NULL;
1832 
1833 	page = vm_normal_page(vma, addr, pte);
1834 	if (!page || is_zone_device_page(page))
1835 		return NULL;
1836 
1837 	if (PageReserved(page))
1838 		return NULL;
1839 
1840 	nid = page_to_nid(page);
1841 	if (!node_isset(nid, node_states[N_MEMORY]))
1842 		return NULL;
1843 
1844 	return page;
1845 }
1846 
1847 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1848 static struct page *can_gather_numa_stats_pmd(pmd_t pmd,
1849 					      struct vm_area_struct *vma,
1850 					      unsigned long addr)
1851 {
1852 	struct page *page;
1853 	int nid;
1854 
1855 	if (!pmd_present(pmd))
1856 		return NULL;
1857 
1858 	page = vm_normal_page_pmd(vma, addr, pmd);
1859 	if (!page)
1860 		return NULL;
1861 
1862 	if (PageReserved(page))
1863 		return NULL;
1864 
1865 	nid = page_to_nid(page);
1866 	if (!node_isset(nid, node_states[N_MEMORY]))
1867 		return NULL;
1868 
1869 	return page;
1870 }
1871 #endif
1872 
1873 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
1874 		unsigned long end, struct mm_walk *walk)
1875 {
1876 	struct numa_maps *md = walk->private;
1877 	struct vm_area_struct *vma = walk->vma;
1878 	spinlock_t *ptl;
1879 	pte_t *orig_pte;
1880 	pte_t *pte;
1881 
1882 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1883 	ptl = pmd_trans_huge_lock(pmd, vma);
1884 	if (ptl) {
1885 		struct page *page;
1886 
1887 		page = can_gather_numa_stats_pmd(*pmd, vma, addr);
1888 		if (page)
1889 			gather_stats(page, md, pmd_dirty(*pmd),
1890 				     HPAGE_PMD_SIZE/PAGE_SIZE);
1891 		spin_unlock(ptl);
1892 		return 0;
1893 	}
1894 #endif
1895 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
1896 	if (!pte) {
1897 		walk->action = ACTION_AGAIN;
1898 		return 0;
1899 	}
1900 	do {
1901 		pte_t ptent = ptep_get(pte);
1902 		struct page *page = can_gather_numa_stats(ptent, vma, addr);
1903 		if (!page)
1904 			continue;
1905 		gather_stats(page, md, pte_dirty(ptent), 1);
1906 
1907 	} while (pte++, addr += PAGE_SIZE, addr != end);
1908 	pte_unmap_unlock(orig_pte, ptl);
1909 	cond_resched();
1910 	return 0;
1911 }
1912 #ifdef CONFIG_HUGETLB_PAGE
1913 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1914 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1915 {
1916 	pte_t huge_pte = huge_ptep_get(pte);
1917 	struct numa_maps *md;
1918 	struct page *page;
1919 
1920 	if (!pte_present(huge_pte))
1921 		return 0;
1922 
1923 	page = pte_page(huge_pte);
1924 
1925 	md = walk->private;
1926 	gather_stats(page, md, pte_dirty(huge_pte), 1);
1927 	return 0;
1928 }
1929 
1930 #else
1931 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1932 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1933 {
1934 	return 0;
1935 }
1936 #endif
1937 
1938 static const struct mm_walk_ops show_numa_ops = {
1939 	.hugetlb_entry = gather_hugetlb_stats,
1940 	.pmd_entry = gather_pte_stats,
1941 	.walk_lock = PGWALK_RDLOCK,
1942 };
1943 
1944 /*
1945  * Display pages allocated per node and memory policy via /proc.
1946  */
1947 static int show_numa_map(struct seq_file *m, void *v)
1948 {
1949 	struct numa_maps_private *numa_priv = m->private;
1950 	struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
1951 	struct vm_area_struct *vma = v;
1952 	struct numa_maps *md = &numa_priv->md;
1953 	struct file *file = vma->vm_file;
1954 	struct mm_struct *mm = vma->vm_mm;
1955 	struct mempolicy *pol;
1956 	char buffer[64];
1957 	int nid;
1958 
1959 	if (!mm)
1960 		return 0;
1961 
1962 	/* Ensure we start with an empty set of numa_maps statistics. */
1963 	memset(md, 0, sizeof(*md));
1964 
1965 	pol = __get_vma_policy(vma, vma->vm_start);
1966 	if (pol) {
1967 		mpol_to_str(buffer, sizeof(buffer), pol);
1968 		mpol_cond_put(pol);
1969 	} else {
1970 		mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
1971 	}
1972 
1973 	seq_printf(m, "%08lx %s", vma->vm_start, buffer);
1974 
1975 	if (file) {
1976 		seq_puts(m, " file=");
1977 		seq_file_path(m, file, "\n\t= ");
1978 	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
1979 		seq_puts(m, " heap");
1980 	} else if (is_stack(vma)) {
1981 		seq_puts(m, " stack");
1982 	}
1983 
1984 	if (is_vm_hugetlb_page(vma))
1985 		seq_puts(m, " huge");
1986 
1987 	/* mmap_lock is held by m_start */
1988 	walk_page_vma(vma, &show_numa_ops, md);
1989 
1990 	if (!md->pages)
1991 		goto out;
1992 
1993 	if (md->anon)
1994 		seq_printf(m, " anon=%lu", md->anon);
1995 
1996 	if (md->dirty)
1997 		seq_printf(m, " dirty=%lu", md->dirty);
1998 
1999 	if (md->pages != md->anon && md->pages != md->dirty)
2000 		seq_printf(m, " mapped=%lu", md->pages);
2001 
2002 	if (md->mapcount_max > 1)
2003 		seq_printf(m, " mapmax=%lu", md->mapcount_max);
2004 
2005 	if (md->swapcache)
2006 		seq_printf(m, " swapcache=%lu", md->swapcache);
2007 
2008 	if (md->active < md->pages && !is_vm_hugetlb_page(vma))
2009 		seq_printf(m, " active=%lu", md->active);
2010 
2011 	if (md->writeback)
2012 		seq_printf(m, " writeback=%lu", md->writeback);
2013 
2014 	for_each_node_state(nid, N_MEMORY)
2015 		if (md->node[nid])
2016 			seq_printf(m, " N%d=%lu", nid, md->node[nid]);
2017 
2018 	seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
2019 out:
2020 	seq_putc(m, '\n');
2021 	return 0;
2022 }
2023 
2024 static const struct seq_operations proc_pid_numa_maps_op = {
2025 	.start  = m_start,
2026 	.next   = m_next,
2027 	.stop   = m_stop,
2028 	.show   = show_numa_map,
2029 };
2030 
2031 static int pid_numa_maps_open(struct inode *inode, struct file *file)
2032 {
2033 	return proc_maps_open(inode, file, &proc_pid_numa_maps_op,
2034 				sizeof(struct numa_maps_private));
2035 }
2036 
2037 const struct file_operations proc_pid_numa_maps_operations = {
2038 	.open		= pid_numa_maps_open,
2039 	.read		= seq_read,
2040 	.llseek		= seq_lseek,
2041 	.release	= proc_map_release,
2042 };
2043 
2044 #endif /* CONFIG_NUMA */
2045