xref: /openbmc/linux/fs/proc/task_mmu.c (revision 93d90ad7)
1 #include <linux/mm.h>
2 #include <linux/vmacache.h>
3 #include <linux/hugetlb.h>
4 #include <linux/huge_mm.h>
5 #include <linux/mount.h>
6 #include <linux/seq_file.h>
7 #include <linux/highmem.h>
8 #include <linux/ptrace.h>
9 #include <linux/slab.h>
10 #include <linux/pagemap.h>
11 #include <linux/mempolicy.h>
12 #include <linux/rmap.h>
13 #include <linux/swap.h>
14 #include <linux/swapops.h>
15 #include <linux/mmu_notifier.h>
16 
17 #include <asm/elf.h>
18 #include <asm/uaccess.h>
19 #include <asm/tlbflush.h>
20 #include "internal.h"
21 
22 void task_mem(struct seq_file *m, struct mm_struct *mm)
23 {
24 	unsigned long data, text, lib, swap;
25 	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
26 
27 	/*
28 	 * Note: to minimize their overhead, mm maintains hiwater_vm and
29 	 * hiwater_rss only when about to *lower* total_vm or rss.  Any
30 	 * collector of these hiwater stats must therefore get total_vm
31 	 * and rss too, which will usually be the higher.  Barriers? not
32 	 * worth the effort, such snapshots can always be inconsistent.
33 	 */
34 	hiwater_vm = total_vm = mm->total_vm;
35 	if (hiwater_vm < mm->hiwater_vm)
36 		hiwater_vm = mm->hiwater_vm;
37 	hiwater_rss = total_rss = get_mm_rss(mm);
38 	if (hiwater_rss < mm->hiwater_rss)
39 		hiwater_rss = mm->hiwater_rss;
40 
41 	data = mm->total_vm - mm->shared_vm - mm->stack_vm;
42 	text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
43 	lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
44 	swap = get_mm_counter(mm, MM_SWAPENTS);
45 	seq_printf(m,
46 		"VmPeak:\t%8lu kB\n"
47 		"VmSize:\t%8lu kB\n"
48 		"VmLck:\t%8lu kB\n"
49 		"VmPin:\t%8lu kB\n"
50 		"VmHWM:\t%8lu kB\n"
51 		"VmRSS:\t%8lu kB\n"
52 		"VmData:\t%8lu kB\n"
53 		"VmStk:\t%8lu kB\n"
54 		"VmExe:\t%8lu kB\n"
55 		"VmLib:\t%8lu kB\n"
56 		"VmPTE:\t%8lu kB\n"
57 		"VmSwap:\t%8lu kB\n",
58 		hiwater_vm << (PAGE_SHIFT-10),
59 		total_vm << (PAGE_SHIFT-10),
60 		mm->locked_vm << (PAGE_SHIFT-10),
61 		mm->pinned_vm << (PAGE_SHIFT-10),
62 		hiwater_rss << (PAGE_SHIFT-10),
63 		total_rss << (PAGE_SHIFT-10),
64 		data << (PAGE_SHIFT-10),
65 		mm->stack_vm << (PAGE_SHIFT-10), text, lib,
66 		(PTRS_PER_PTE * sizeof(pte_t) *
67 		 atomic_long_read(&mm->nr_ptes)) >> 10,
68 		swap << (PAGE_SHIFT-10));
69 }
70 
71 unsigned long task_vsize(struct mm_struct *mm)
72 {
73 	return PAGE_SIZE * mm->total_vm;
74 }
75 
76 unsigned long task_statm(struct mm_struct *mm,
77 			 unsigned long *shared, unsigned long *text,
78 			 unsigned long *data, unsigned long *resident)
79 {
80 	*shared = get_mm_counter(mm, MM_FILEPAGES);
81 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
82 								>> PAGE_SHIFT;
83 	*data = mm->total_vm - mm->shared_vm;
84 	*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
85 	return mm->total_vm;
86 }
87 
88 #ifdef CONFIG_NUMA
89 /*
90  * Save get_task_policy() for show_numa_map().
91  */
92 static void hold_task_mempolicy(struct proc_maps_private *priv)
93 {
94 	struct task_struct *task = priv->task;
95 
96 	task_lock(task);
97 	priv->task_mempolicy = get_task_policy(task);
98 	mpol_get(priv->task_mempolicy);
99 	task_unlock(task);
100 }
101 static void release_task_mempolicy(struct proc_maps_private *priv)
102 {
103 	mpol_put(priv->task_mempolicy);
104 }
105 #else
106 static void hold_task_mempolicy(struct proc_maps_private *priv)
107 {
108 }
109 static void release_task_mempolicy(struct proc_maps_private *priv)
110 {
111 }
112 #endif
113 
114 static void vma_stop(struct proc_maps_private *priv)
115 {
116 	struct mm_struct *mm = priv->mm;
117 
118 	release_task_mempolicy(priv);
119 	up_read(&mm->mmap_sem);
120 	mmput(mm);
121 }
122 
123 static struct vm_area_struct *
124 m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
125 {
126 	if (vma == priv->tail_vma)
127 		return NULL;
128 	return vma->vm_next ?: priv->tail_vma;
129 }
130 
131 static void m_cache_vma(struct seq_file *m, struct vm_area_struct *vma)
132 {
133 	if (m->count < m->size)	/* vma is copied successfully */
134 		m->version = m_next_vma(m->private, vma) ? vma->vm_start : -1UL;
135 }
136 
137 static void *m_start(struct seq_file *m, loff_t *ppos)
138 {
139 	struct proc_maps_private *priv = m->private;
140 	unsigned long last_addr = m->version;
141 	struct mm_struct *mm;
142 	struct vm_area_struct *vma;
143 	unsigned int pos = *ppos;
144 
145 	/* See m_cache_vma(). Zero at the start or after lseek. */
146 	if (last_addr == -1UL)
147 		return NULL;
148 
149 	priv->task = get_proc_task(priv->inode);
150 	if (!priv->task)
151 		return ERR_PTR(-ESRCH);
152 
153 	mm = priv->mm;
154 	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
155 		return NULL;
156 
157 	down_read(&mm->mmap_sem);
158 	hold_task_mempolicy(priv);
159 	priv->tail_vma = get_gate_vma(mm);
160 
161 	if (last_addr) {
162 		vma = find_vma(mm, last_addr);
163 		if (vma && (vma = m_next_vma(priv, vma)))
164 			return vma;
165 	}
166 
167 	m->version = 0;
168 	if (pos < mm->map_count) {
169 		for (vma = mm->mmap; pos; pos--) {
170 			m->version = vma->vm_start;
171 			vma = vma->vm_next;
172 		}
173 		return vma;
174 	}
175 
176 	/* we do not bother to update m->version in this case */
177 	if (pos == mm->map_count && priv->tail_vma)
178 		return priv->tail_vma;
179 
180 	vma_stop(priv);
181 	return NULL;
182 }
183 
184 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
185 {
186 	struct proc_maps_private *priv = m->private;
187 	struct vm_area_struct *next;
188 
189 	(*pos)++;
190 	next = m_next_vma(priv, v);
191 	if (!next)
192 		vma_stop(priv);
193 	return next;
194 }
195 
196 static void m_stop(struct seq_file *m, void *v)
197 {
198 	struct proc_maps_private *priv = m->private;
199 
200 	if (!IS_ERR_OR_NULL(v))
201 		vma_stop(priv);
202 	if (priv->task) {
203 		put_task_struct(priv->task);
204 		priv->task = NULL;
205 	}
206 }
207 
208 static int proc_maps_open(struct inode *inode, struct file *file,
209 			const struct seq_operations *ops, int psize)
210 {
211 	struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
212 
213 	if (!priv)
214 		return -ENOMEM;
215 
216 	priv->inode = inode;
217 	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
218 	if (IS_ERR(priv->mm)) {
219 		int err = PTR_ERR(priv->mm);
220 
221 		seq_release_private(inode, file);
222 		return err;
223 	}
224 
225 	return 0;
226 }
227 
228 static int proc_map_release(struct inode *inode, struct file *file)
229 {
230 	struct seq_file *seq = file->private_data;
231 	struct proc_maps_private *priv = seq->private;
232 
233 	if (priv->mm)
234 		mmdrop(priv->mm);
235 
236 	return seq_release_private(inode, file);
237 }
238 
239 static int do_maps_open(struct inode *inode, struct file *file,
240 			const struct seq_operations *ops)
241 {
242 	return proc_maps_open(inode, file, ops,
243 				sizeof(struct proc_maps_private));
244 }
245 
246 static pid_t pid_of_stack(struct proc_maps_private *priv,
247 				struct vm_area_struct *vma, bool is_pid)
248 {
249 	struct inode *inode = priv->inode;
250 	struct task_struct *task;
251 	pid_t ret = 0;
252 
253 	rcu_read_lock();
254 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
255 	if (task) {
256 		task = task_of_stack(task, vma, is_pid);
257 		if (task)
258 			ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);
259 	}
260 	rcu_read_unlock();
261 
262 	return ret;
263 }
264 
265 static void
266 show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
267 {
268 	struct mm_struct *mm = vma->vm_mm;
269 	struct file *file = vma->vm_file;
270 	struct proc_maps_private *priv = m->private;
271 	vm_flags_t flags = vma->vm_flags;
272 	unsigned long ino = 0;
273 	unsigned long long pgoff = 0;
274 	unsigned long start, end;
275 	dev_t dev = 0;
276 	const char *name = NULL;
277 
278 	if (file) {
279 		struct inode *inode = file_inode(vma->vm_file);
280 		dev = inode->i_sb->s_dev;
281 		ino = inode->i_ino;
282 		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
283 	}
284 
285 	/* We don't show the stack guard page in /proc/maps */
286 	start = vma->vm_start;
287 	if (stack_guard_page_start(vma, start))
288 		start += PAGE_SIZE;
289 	end = vma->vm_end;
290 	if (stack_guard_page_end(vma, end))
291 		end -= PAGE_SIZE;
292 
293 	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
294 	seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
295 			start,
296 			end,
297 			flags & VM_READ ? 'r' : '-',
298 			flags & VM_WRITE ? 'w' : '-',
299 			flags & VM_EXEC ? 'x' : '-',
300 			flags & VM_MAYSHARE ? 's' : 'p',
301 			pgoff,
302 			MAJOR(dev), MINOR(dev), ino);
303 
304 	/*
305 	 * Print the dentry name for named mappings, and a
306 	 * special [heap] marker for the heap:
307 	 */
308 	if (file) {
309 		seq_pad(m, ' ');
310 		seq_path(m, &file->f_path, "\n");
311 		goto done;
312 	}
313 
314 	if (vma->vm_ops && vma->vm_ops->name) {
315 		name = vma->vm_ops->name(vma);
316 		if (name)
317 			goto done;
318 	}
319 
320 	name = arch_vma_name(vma);
321 	if (!name) {
322 		pid_t tid;
323 
324 		if (!mm) {
325 			name = "[vdso]";
326 			goto done;
327 		}
328 
329 		if (vma->vm_start <= mm->brk &&
330 		    vma->vm_end >= mm->start_brk) {
331 			name = "[heap]";
332 			goto done;
333 		}
334 
335 		tid = pid_of_stack(priv, vma, is_pid);
336 		if (tid != 0) {
337 			/*
338 			 * Thread stack in /proc/PID/task/TID/maps or
339 			 * the main process stack.
340 			 */
341 			if (!is_pid || (vma->vm_start <= mm->start_stack &&
342 			    vma->vm_end >= mm->start_stack)) {
343 				name = "[stack]";
344 			} else {
345 				/* Thread stack in /proc/PID/maps */
346 				seq_pad(m, ' ');
347 				seq_printf(m, "[stack:%d]", tid);
348 			}
349 		}
350 	}
351 
352 done:
353 	if (name) {
354 		seq_pad(m, ' ');
355 		seq_puts(m, name);
356 	}
357 	seq_putc(m, '\n');
358 }
359 
360 static int show_map(struct seq_file *m, void *v, int is_pid)
361 {
362 	show_map_vma(m, v, is_pid);
363 	m_cache_vma(m, v);
364 	return 0;
365 }
366 
367 static int show_pid_map(struct seq_file *m, void *v)
368 {
369 	return show_map(m, v, 1);
370 }
371 
372 static int show_tid_map(struct seq_file *m, void *v)
373 {
374 	return show_map(m, v, 0);
375 }
376 
377 static const struct seq_operations proc_pid_maps_op = {
378 	.start	= m_start,
379 	.next	= m_next,
380 	.stop	= m_stop,
381 	.show	= show_pid_map
382 };
383 
384 static const struct seq_operations proc_tid_maps_op = {
385 	.start	= m_start,
386 	.next	= m_next,
387 	.stop	= m_stop,
388 	.show	= show_tid_map
389 };
390 
391 static int pid_maps_open(struct inode *inode, struct file *file)
392 {
393 	return do_maps_open(inode, file, &proc_pid_maps_op);
394 }
395 
396 static int tid_maps_open(struct inode *inode, struct file *file)
397 {
398 	return do_maps_open(inode, file, &proc_tid_maps_op);
399 }
400 
401 const struct file_operations proc_pid_maps_operations = {
402 	.open		= pid_maps_open,
403 	.read		= seq_read,
404 	.llseek		= seq_lseek,
405 	.release	= proc_map_release,
406 };
407 
408 const struct file_operations proc_tid_maps_operations = {
409 	.open		= tid_maps_open,
410 	.read		= seq_read,
411 	.llseek		= seq_lseek,
412 	.release	= proc_map_release,
413 };
414 
415 /*
416  * Proportional Set Size(PSS): my share of RSS.
417  *
418  * PSS of a process is the count of pages it has in memory, where each
419  * page is divided by the number of processes sharing it.  So if a
420  * process has 1000 pages all to itself, and 1000 shared with one other
421  * process, its PSS will be 1500.
422  *
423  * To keep (accumulated) division errors low, we adopt a 64bit
424  * fixed-point pss counter to minimize division errors. So (pss >>
425  * PSS_SHIFT) would be the real byte count.
426  *
427  * A shift of 12 before division means (assuming 4K page size):
428  * 	- 1M 3-user-pages add up to 8KB errors;
429  * 	- supports mapcount up to 2^24, or 16M;
430  * 	- supports PSS up to 2^52 bytes, or 4PB.
431  */
432 #define PSS_SHIFT 12
433 
434 #ifdef CONFIG_PROC_PAGE_MONITOR
435 struct mem_size_stats {
436 	struct vm_area_struct *vma;
437 	unsigned long resident;
438 	unsigned long shared_clean;
439 	unsigned long shared_dirty;
440 	unsigned long private_clean;
441 	unsigned long private_dirty;
442 	unsigned long referenced;
443 	unsigned long anonymous;
444 	unsigned long anonymous_thp;
445 	unsigned long swap;
446 	unsigned long nonlinear;
447 	u64 pss;
448 };
449 
450 static void smaps_account(struct mem_size_stats *mss, struct page *page,
451 		unsigned long size, bool young, bool dirty)
452 {
453 	int mapcount;
454 
455 	if (PageAnon(page))
456 		mss->anonymous += size;
457 
458 	mss->resident += size;
459 	/* Accumulate the size in pages that have been accessed. */
460 	if (young || PageReferenced(page))
461 		mss->referenced += size;
462 	mapcount = page_mapcount(page);
463 	if (mapcount >= 2) {
464 		u64 pss_delta;
465 
466 		if (dirty || PageDirty(page))
467 			mss->shared_dirty += size;
468 		else
469 			mss->shared_clean += size;
470 		pss_delta = (u64)size << PSS_SHIFT;
471 		do_div(pss_delta, mapcount);
472 		mss->pss += pss_delta;
473 	} else {
474 		if (dirty || PageDirty(page))
475 			mss->private_dirty += size;
476 		else
477 			mss->private_clean += size;
478 		mss->pss += (u64)size << PSS_SHIFT;
479 	}
480 }
481 
482 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
483 		struct mm_walk *walk)
484 {
485 	struct mem_size_stats *mss = walk->private;
486 	struct vm_area_struct *vma = mss->vma;
487 	pgoff_t pgoff = linear_page_index(vma, addr);
488 	struct page *page = NULL;
489 
490 	if (pte_present(*pte)) {
491 		page = vm_normal_page(vma, addr, *pte);
492 	} else if (is_swap_pte(*pte)) {
493 		swp_entry_t swpent = pte_to_swp_entry(*pte);
494 
495 		if (!non_swap_entry(swpent))
496 			mss->swap += PAGE_SIZE;
497 		else if (is_migration_entry(swpent))
498 			page = migration_entry_to_page(swpent);
499 	} else if (pte_file(*pte)) {
500 		if (pte_to_pgoff(*pte) != pgoff)
501 			mss->nonlinear += PAGE_SIZE;
502 	}
503 
504 	if (!page)
505 		return;
506 
507 	if (page->index != pgoff)
508 		mss->nonlinear += PAGE_SIZE;
509 
510 	smaps_account(mss, page, PAGE_SIZE, pte_young(*pte), pte_dirty(*pte));
511 }
512 
513 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
514 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
515 		struct mm_walk *walk)
516 {
517 	struct mem_size_stats *mss = walk->private;
518 	struct vm_area_struct *vma = mss->vma;
519 	struct page *page;
520 
521 	/* FOLL_DUMP will return -EFAULT on huge zero page */
522 	page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
523 	if (IS_ERR_OR_NULL(page))
524 		return;
525 	mss->anonymous_thp += HPAGE_PMD_SIZE;
526 	smaps_account(mss, page, HPAGE_PMD_SIZE,
527 			pmd_young(*pmd), pmd_dirty(*pmd));
528 }
529 #else
530 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
531 		struct mm_walk *walk)
532 {
533 }
534 #endif
535 
536 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
537 			   struct mm_walk *walk)
538 {
539 	struct mem_size_stats *mss = walk->private;
540 	struct vm_area_struct *vma = mss->vma;
541 	pte_t *pte;
542 	spinlock_t *ptl;
543 
544 	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
545 		smaps_pmd_entry(pmd, addr, walk);
546 		spin_unlock(ptl);
547 		return 0;
548 	}
549 
550 	if (pmd_trans_unstable(pmd))
551 		return 0;
552 	/*
553 	 * The mmap_sem held all the way back in m_start() is what
554 	 * keeps khugepaged out of here and from collapsing things
555 	 * in here.
556 	 */
557 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
558 	for (; addr != end; pte++, addr += PAGE_SIZE)
559 		smaps_pte_entry(pte, addr, walk);
560 	pte_unmap_unlock(pte - 1, ptl);
561 	cond_resched();
562 	return 0;
563 }
564 
565 static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
566 {
567 	/*
568 	 * Don't forget to update Documentation/ on changes.
569 	 */
570 	static const char mnemonics[BITS_PER_LONG][2] = {
571 		/*
572 		 * In case if we meet a flag we don't know about.
573 		 */
574 		[0 ... (BITS_PER_LONG-1)] = "??",
575 
576 		[ilog2(VM_READ)]	= "rd",
577 		[ilog2(VM_WRITE)]	= "wr",
578 		[ilog2(VM_EXEC)]	= "ex",
579 		[ilog2(VM_SHARED)]	= "sh",
580 		[ilog2(VM_MAYREAD)]	= "mr",
581 		[ilog2(VM_MAYWRITE)]	= "mw",
582 		[ilog2(VM_MAYEXEC)]	= "me",
583 		[ilog2(VM_MAYSHARE)]	= "ms",
584 		[ilog2(VM_GROWSDOWN)]	= "gd",
585 		[ilog2(VM_PFNMAP)]	= "pf",
586 		[ilog2(VM_DENYWRITE)]	= "dw",
587 #ifdef CONFIG_X86_INTEL_MPX
588 		[ilog2(VM_MPX)]		= "mp",
589 #endif
590 		[ilog2(VM_LOCKED)]	= "lo",
591 		[ilog2(VM_IO)]		= "io",
592 		[ilog2(VM_SEQ_READ)]	= "sr",
593 		[ilog2(VM_RAND_READ)]	= "rr",
594 		[ilog2(VM_DONTCOPY)]	= "dc",
595 		[ilog2(VM_DONTEXPAND)]	= "de",
596 		[ilog2(VM_ACCOUNT)]	= "ac",
597 		[ilog2(VM_NORESERVE)]	= "nr",
598 		[ilog2(VM_HUGETLB)]	= "ht",
599 		[ilog2(VM_NONLINEAR)]	= "nl",
600 		[ilog2(VM_ARCH_1)]	= "ar",
601 		[ilog2(VM_DONTDUMP)]	= "dd",
602 #ifdef CONFIG_MEM_SOFT_DIRTY
603 		[ilog2(VM_SOFTDIRTY)]	= "sd",
604 #endif
605 		[ilog2(VM_MIXEDMAP)]	= "mm",
606 		[ilog2(VM_HUGEPAGE)]	= "hg",
607 		[ilog2(VM_NOHUGEPAGE)]	= "nh",
608 		[ilog2(VM_MERGEABLE)]	= "mg",
609 	};
610 	size_t i;
611 
612 	seq_puts(m, "VmFlags: ");
613 	for (i = 0; i < BITS_PER_LONG; i++) {
614 		if (vma->vm_flags & (1UL << i)) {
615 			seq_printf(m, "%c%c ",
616 				   mnemonics[i][0], mnemonics[i][1]);
617 		}
618 	}
619 	seq_putc(m, '\n');
620 }
621 
622 static int show_smap(struct seq_file *m, void *v, int is_pid)
623 {
624 	struct vm_area_struct *vma = v;
625 	struct mem_size_stats mss;
626 	struct mm_walk smaps_walk = {
627 		.pmd_entry = smaps_pte_range,
628 		.mm = vma->vm_mm,
629 		.private = &mss,
630 	};
631 
632 	memset(&mss, 0, sizeof mss);
633 	mss.vma = vma;
634 	/* mmap_sem is held in m_start */
635 	if (vma->vm_mm && !is_vm_hugetlb_page(vma))
636 		walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
637 
638 	show_map_vma(m, vma, is_pid);
639 
640 	seq_printf(m,
641 		   "Size:           %8lu kB\n"
642 		   "Rss:            %8lu kB\n"
643 		   "Pss:            %8lu kB\n"
644 		   "Shared_Clean:   %8lu kB\n"
645 		   "Shared_Dirty:   %8lu kB\n"
646 		   "Private_Clean:  %8lu kB\n"
647 		   "Private_Dirty:  %8lu kB\n"
648 		   "Referenced:     %8lu kB\n"
649 		   "Anonymous:      %8lu kB\n"
650 		   "AnonHugePages:  %8lu kB\n"
651 		   "Swap:           %8lu kB\n"
652 		   "KernelPageSize: %8lu kB\n"
653 		   "MMUPageSize:    %8lu kB\n"
654 		   "Locked:         %8lu kB\n",
655 		   (vma->vm_end - vma->vm_start) >> 10,
656 		   mss.resident >> 10,
657 		   (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
658 		   mss.shared_clean  >> 10,
659 		   mss.shared_dirty  >> 10,
660 		   mss.private_clean >> 10,
661 		   mss.private_dirty >> 10,
662 		   mss.referenced >> 10,
663 		   mss.anonymous >> 10,
664 		   mss.anonymous_thp >> 10,
665 		   mss.swap >> 10,
666 		   vma_kernel_pagesize(vma) >> 10,
667 		   vma_mmu_pagesize(vma) >> 10,
668 		   (vma->vm_flags & VM_LOCKED) ?
669 			(unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
670 
671 	if (vma->vm_flags & VM_NONLINEAR)
672 		seq_printf(m, "Nonlinear:      %8lu kB\n",
673 				mss.nonlinear >> 10);
674 
675 	show_smap_vma_flags(m, vma);
676 	m_cache_vma(m, vma);
677 	return 0;
678 }
679 
680 static int show_pid_smap(struct seq_file *m, void *v)
681 {
682 	return show_smap(m, v, 1);
683 }
684 
685 static int show_tid_smap(struct seq_file *m, void *v)
686 {
687 	return show_smap(m, v, 0);
688 }
689 
690 static const struct seq_operations proc_pid_smaps_op = {
691 	.start	= m_start,
692 	.next	= m_next,
693 	.stop	= m_stop,
694 	.show	= show_pid_smap
695 };
696 
697 static const struct seq_operations proc_tid_smaps_op = {
698 	.start	= m_start,
699 	.next	= m_next,
700 	.stop	= m_stop,
701 	.show	= show_tid_smap
702 };
703 
704 static int pid_smaps_open(struct inode *inode, struct file *file)
705 {
706 	return do_maps_open(inode, file, &proc_pid_smaps_op);
707 }
708 
709 static int tid_smaps_open(struct inode *inode, struct file *file)
710 {
711 	return do_maps_open(inode, file, &proc_tid_smaps_op);
712 }
713 
714 const struct file_operations proc_pid_smaps_operations = {
715 	.open		= pid_smaps_open,
716 	.read		= seq_read,
717 	.llseek		= seq_lseek,
718 	.release	= proc_map_release,
719 };
720 
721 const struct file_operations proc_tid_smaps_operations = {
722 	.open		= tid_smaps_open,
723 	.read		= seq_read,
724 	.llseek		= seq_lseek,
725 	.release	= proc_map_release,
726 };
727 
728 /*
729  * We do not want to have constant page-shift bits sitting in
730  * pagemap entries and are about to reuse them some time soon.
731  *
732  * Here's the "migration strategy":
733  * 1. when the system boots these bits remain what they are,
734  *    but a warning about future change is printed in log;
735  * 2. once anyone clears soft-dirty bits via clear_refs file,
736  *    these flag is set to denote, that user is aware of the
737  *    new API and those page-shift bits change their meaning.
738  *    The respective warning is printed in dmesg;
739  * 3. In a couple of releases we will remove all the mentions
740  *    of page-shift in pagemap entries.
741  */
742 
743 static bool soft_dirty_cleared __read_mostly;
744 
745 enum clear_refs_types {
746 	CLEAR_REFS_ALL = 1,
747 	CLEAR_REFS_ANON,
748 	CLEAR_REFS_MAPPED,
749 	CLEAR_REFS_SOFT_DIRTY,
750 	CLEAR_REFS_LAST,
751 };
752 
753 struct clear_refs_private {
754 	struct vm_area_struct *vma;
755 	enum clear_refs_types type;
756 };
757 
758 static inline void clear_soft_dirty(struct vm_area_struct *vma,
759 		unsigned long addr, pte_t *pte)
760 {
761 #ifdef CONFIG_MEM_SOFT_DIRTY
762 	/*
763 	 * The soft-dirty tracker uses #PF-s to catch writes
764 	 * to pages, so write-protect the pte as well. See the
765 	 * Documentation/vm/soft-dirty.txt for full description
766 	 * of how soft-dirty works.
767 	 */
768 	pte_t ptent = *pte;
769 
770 	if (pte_present(ptent)) {
771 		ptent = pte_wrprotect(ptent);
772 		ptent = pte_clear_flags(ptent, _PAGE_SOFT_DIRTY);
773 	} else if (is_swap_pte(ptent)) {
774 		ptent = pte_swp_clear_soft_dirty(ptent);
775 	} else if (pte_file(ptent)) {
776 		ptent = pte_file_clear_soft_dirty(ptent);
777 	}
778 
779 	set_pte_at(vma->vm_mm, addr, pte, ptent);
780 #endif
781 }
782 
783 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
784 				unsigned long end, struct mm_walk *walk)
785 {
786 	struct clear_refs_private *cp = walk->private;
787 	struct vm_area_struct *vma = cp->vma;
788 	pte_t *pte, ptent;
789 	spinlock_t *ptl;
790 	struct page *page;
791 
792 	split_huge_page_pmd(vma, addr, pmd);
793 	if (pmd_trans_unstable(pmd))
794 		return 0;
795 
796 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
797 	for (; addr != end; pte++, addr += PAGE_SIZE) {
798 		ptent = *pte;
799 
800 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
801 			clear_soft_dirty(vma, addr, pte);
802 			continue;
803 		}
804 
805 		if (!pte_present(ptent))
806 			continue;
807 
808 		page = vm_normal_page(vma, addr, ptent);
809 		if (!page)
810 			continue;
811 
812 		/* Clear accessed and referenced bits. */
813 		ptep_test_and_clear_young(vma, addr, pte);
814 		ClearPageReferenced(page);
815 	}
816 	pte_unmap_unlock(pte - 1, ptl);
817 	cond_resched();
818 	return 0;
819 }
820 
821 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
822 				size_t count, loff_t *ppos)
823 {
824 	struct task_struct *task;
825 	char buffer[PROC_NUMBUF];
826 	struct mm_struct *mm;
827 	struct vm_area_struct *vma;
828 	enum clear_refs_types type;
829 	int itype;
830 	int rv;
831 
832 	memset(buffer, 0, sizeof(buffer));
833 	if (count > sizeof(buffer) - 1)
834 		count = sizeof(buffer) - 1;
835 	if (copy_from_user(buffer, buf, count))
836 		return -EFAULT;
837 	rv = kstrtoint(strstrip(buffer), 10, &itype);
838 	if (rv < 0)
839 		return rv;
840 	type = (enum clear_refs_types)itype;
841 	if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
842 		return -EINVAL;
843 
844 	if (type == CLEAR_REFS_SOFT_DIRTY) {
845 		soft_dirty_cleared = true;
846 		pr_warn_once("The pagemap bits 55-60 has changed their meaning!"
847 			     " See the linux/Documentation/vm/pagemap.txt for "
848 			     "details.\n");
849 	}
850 
851 	task = get_proc_task(file_inode(file));
852 	if (!task)
853 		return -ESRCH;
854 	mm = get_task_mm(task);
855 	if (mm) {
856 		struct clear_refs_private cp = {
857 			.type = type,
858 		};
859 		struct mm_walk clear_refs_walk = {
860 			.pmd_entry = clear_refs_pte_range,
861 			.mm = mm,
862 			.private = &cp,
863 		};
864 		down_read(&mm->mmap_sem);
865 		if (type == CLEAR_REFS_SOFT_DIRTY) {
866 			for (vma = mm->mmap; vma; vma = vma->vm_next) {
867 				if (!(vma->vm_flags & VM_SOFTDIRTY))
868 					continue;
869 				up_read(&mm->mmap_sem);
870 				down_write(&mm->mmap_sem);
871 				for (vma = mm->mmap; vma; vma = vma->vm_next) {
872 					vma->vm_flags &= ~VM_SOFTDIRTY;
873 					vma_set_page_prot(vma);
874 				}
875 				downgrade_write(&mm->mmap_sem);
876 				break;
877 			}
878 			mmu_notifier_invalidate_range_start(mm, 0, -1);
879 		}
880 		for (vma = mm->mmap; vma; vma = vma->vm_next) {
881 			cp.vma = vma;
882 			if (is_vm_hugetlb_page(vma))
883 				continue;
884 			/*
885 			 * Writing 1 to /proc/pid/clear_refs affects all pages.
886 			 *
887 			 * Writing 2 to /proc/pid/clear_refs only affects
888 			 * Anonymous pages.
889 			 *
890 			 * Writing 3 to /proc/pid/clear_refs only affects file
891 			 * mapped pages.
892 			 *
893 			 * Writing 4 to /proc/pid/clear_refs affects all pages.
894 			 */
895 			if (type == CLEAR_REFS_ANON && vma->vm_file)
896 				continue;
897 			if (type == CLEAR_REFS_MAPPED && !vma->vm_file)
898 				continue;
899 			walk_page_range(vma->vm_start, vma->vm_end,
900 					&clear_refs_walk);
901 		}
902 		if (type == CLEAR_REFS_SOFT_DIRTY)
903 			mmu_notifier_invalidate_range_end(mm, 0, -1);
904 		flush_tlb_mm(mm);
905 		up_read(&mm->mmap_sem);
906 		mmput(mm);
907 	}
908 	put_task_struct(task);
909 
910 	return count;
911 }
912 
913 const struct file_operations proc_clear_refs_operations = {
914 	.write		= clear_refs_write,
915 	.llseek		= noop_llseek,
916 };
917 
918 typedef struct {
919 	u64 pme;
920 } pagemap_entry_t;
921 
922 struct pagemapread {
923 	int pos, len;		/* units: PM_ENTRY_BYTES, not bytes */
924 	pagemap_entry_t *buffer;
925 	bool v2;
926 };
927 
928 #define PAGEMAP_WALK_SIZE	(PMD_SIZE)
929 #define PAGEMAP_WALK_MASK	(PMD_MASK)
930 
931 #define PM_ENTRY_BYTES      sizeof(pagemap_entry_t)
932 #define PM_STATUS_BITS      3
933 #define PM_STATUS_OFFSET    (64 - PM_STATUS_BITS)
934 #define PM_STATUS_MASK      (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
935 #define PM_STATUS(nr)       (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
936 #define PM_PSHIFT_BITS      6
937 #define PM_PSHIFT_OFFSET    (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
938 #define PM_PSHIFT_MASK      (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
939 #define __PM_PSHIFT(x)      (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
940 #define PM_PFRAME_MASK      ((1LL << PM_PSHIFT_OFFSET) - 1)
941 #define PM_PFRAME(x)        ((x) & PM_PFRAME_MASK)
942 /* in "new" pagemap pshift bits are occupied with more status bits */
943 #define PM_STATUS2(v2, x)   (__PM_PSHIFT(v2 ? x : PAGE_SHIFT))
944 
945 #define __PM_SOFT_DIRTY      (1LL)
946 #define PM_PRESENT          PM_STATUS(4LL)
947 #define PM_SWAP             PM_STATUS(2LL)
948 #define PM_FILE             PM_STATUS(1LL)
949 #define PM_NOT_PRESENT(v2)  PM_STATUS2(v2, 0)
950 #define PM_END_OF_BUFFER    1
951 
952 static inline pagemap_entry_t make_pme(u64 val)
953 {
954 	return (pagemap_entry_t) { .pme = val };
955 }
956 
957 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
958 			  struct pagemapread *pm)
959 {
960 	pm->buffer[pm->pos++] = *pme;
961 	if (pm->pos >= pm->len)
962 		return PM_END_OF_BUFFER;
963 	return 0;
964 }
965 
966 static int pagemap_pte_hole(unsigned long start, unsigned long end,
967 				struct mm_walk *walk)
968 {
969 	struct pagemapread *pm = walk->private;
970 	unsigned long addr = start;
971 	int err = 0;
972 
973 	while (addr < end) {
974 		struct vm_area_struct *vma = find_vma(walk->mm, addr);
975 		pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
976 		/* End of address space hole, which we mark as non-present. */
977 		unsigned long hole_end;
978 
979 		if (vma)
980 			hole_end = min(end, vma->vm_start);
981 		else
982 			hole_end = end;
983 
984 		for (; addr < hole_end; addr += PAGE_SIZE) {
985 			err = add_to_pagemap(addr, &pme, pm);
986 			if (err)
987 				goto out;
988 		}
989 
990 		if (!vma)
991 			break;
992 
993 		/* Addresses in the VMA. */
994 		if (vma->vm_flags & VM_SOFTDIRTY)
995 			pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY);
996 		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
997 			err = add_to_pagemap(addr, &pme, pm);
998 			if (err)
999 				goto out;
1000 		}
1001 	}
1002 out:
1003 	return err;
1004 }
1005 
1006 static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
1007 		struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1008 {
1009 	u64 frame, flags;
1010 	struct page *page = NULL;
1011 	int flags2 = 0;
1012 
1013 	if (pte_present(pte)) {
1014 		frame = pte_pfn(pte);
1015 		flags = PM_PRESENT;
1016 		page = vm_normal_page(vma, addr, pte);
1017 		if (pte_soft_dirty(pte))
1018 			flags2 |= __PM_SOFT_DIRTY;
1019 	} else if (is_swap_pte(pte)) {
1020 		swp_entry_t entry;
1021 		if (pte_swp_soft_dirty(pte))
1022 			flags2 |= __PM_SOFT_DIRTY;
1023 		entry = pte_to_swp_entry(pte);
1024 		frame = swp_type(entry) |
1025 			(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
1026 		flags = PM_SWAP;
1027 		if (is_migration_entry(entry))
1028 			page = migration_entry_to_page(entry);
1029 	} else {
1030 		if (vma->vm_flags & VM_SOFTDIRTY)
1031 			flags2 |= __PM_SOFT_DIRTY;
1032 		*pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, flags2));
1033 		return;
1034 	}
1035 
1036 	if (page && !PageAnon(page))
1037 		flags |= PM_FILE;
1038 	if ((vma->vm_flags & VM_SOFTDIRTY))
1039 		flags2 |= __PM_SOFT_DIRTY;
1040 
1041 	*pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
1042 }
1043 
1044 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1045 static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
1046 		pmd_t pmd, int offset, int pmd_flags2)
1047 {
1048 	/*
1049 	 * Currently pmd for thp is always present because thp can not be
1050 	 * swapped-out, migrated, or HWPOISONed (split in such cases instead.)
1051 	 * This if-check is just to prepare for future implementation.
1052 	 */
1053 	if (pmd_present(pmd))
1054 		*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
1055 				| PM_STATUS2(pm->v2, pmd_flags2) | PM_PRESENT);
1056 	else
1057 		*pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, pmd_flags2));
1058 }
1059 #else
1060 static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
1061 		pmd_t pmd, int offset, int pmd_flags2)
1062 {
1063 }
1064 #endif
1065 
1066 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
1067 			     struct mm_walk *walk)
1068 {
1069 	struct vm_area_struct *vma;
1070 	struct pagemapread *pm = walk->private;
1071 	spinlock_t *ptl;
1072 	pte_t *pte;
1073 	int err = 0;
1074 
1075 	/* find the first VMA at or above 'addr' */
1076 	vma = find_vma(walk->mm, addr);
1077 	if (vma && pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
1078 		int pmd_flags2;
1079 
1080 		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
1081 			pmd_flags2 = __PM_SOFT_DIRTY;
1082 		else
1083 			pmd_flags2 = 0;
1084 
1085 		for (; addr != end; addr += PAGE_SIZE) {
1086 			unsigned long offset;
1087 			pagemap_entry_t pme;
1088 
1089 			offset = (addr & ~PAGEMAP_WALK_MASK) >>
1090 					PAGE_SHIFT;
1091 			thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, pmd_flags2);
1092 			err = add_to_pagemap(addr, &pme, pm);
1093 			if (err)
1094 				break;
1095 		}
1096 		spin_unlock(ptl);
1097 		return err;
1098 	}
1099 
1100 	if (pmd_trans_unstable(pmd))
1101 		return 0;
1102 
1103 	while (1) {
1104 		/* End of address space hole, which we mark as non-present. */
1105 		unsigned long hole_end;
1106 
1107 		if (vma)
1108 			hole_end = min(end, vma->vm_start);
1109 		else
1110 			hole_end = end;
1111 
1112 		for (; addr < hole_end; addr += PAGE_SIZE) {
1113 			pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
1114 
1115 			err = add_to_pagemap(addr, &pme, pm);
1116 			if (err)
1117 				return err;
1118 		}
1119 
1120 		if (!vma || vma->vm_start >= end)
1121 			break;
1122 		/*
1123 		 * We can't possibly be in a hugetlb VMA. In general,
1124 		 * for a mm_walk with a pmd_entry and a hugetlb_entry,
1125 		 * the pmd_entry can only be called on addresses in a
1126 		 * hugetlb if the walk starts in a non-hugetlb VMA and
1127 		 * spans a hugepage VMA. Since pagemap_read walks are
1128 		 * PMD-sized and PMD-aligned, this will never be true.
1129 		 */
1130 		BUG_ON(is_vm_hugetlb_page(vma));
1131 
1132 		/* Addresses in the VMA. */
1133 		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
1134 			pagemap_entry_t pme;
1135 			pte = pte_offset_map(pmd, addr);
1136 			pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
1137 			pte_unmap(pte);
1138 			err = add_to_pagemap(addr, &pme, pm);
1139 			if (err)
1140 				return err;
1141 		}
1142 
1143 		if (addr == end)
1144 			break;
1145 
1146 		vma = find_vma(walk->mm, addr);
1147 	}
1148 
1149 	cond_resched();
1150 
1151 	return err;
1152 }
1153 
1154 #ifdef CONFIG_HUGETLB_PAGE
1155 static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
1156 					pte_t pte, int offset, int flags2)
1157 {
1158 	if (pte_present(pte))
1159 		*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)	|
1160 				PM_STATUS2(pm->v2, flags2)		|
1161 				PM_PRESENT);
1162 	else
1163 		*pme = make_pme(PM_NOT_PRESENT(pm->v2)			|
1164 				PM_STATUS2(pm->v2, flags2));
1165 }
1166 
1167 /* This function walks within one hugetlb entry in the single call */
1168 static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
1169 				 unsigned long addr, unsigned long end,
1170 				 struct mm_walk *walk)
1171 {
1172 	struct pagemapread *pm = walk->private;
1173 	struct vm_area_struct *vma;
1174 	int err = 0;
1175 	int flags2;
1176 	pagemap_entry_t pme;
1177 
1178 	vma = find_vma(walk->mm, addr);
1179 	WARN_ON_ONCE(!vma);
1180 
1181 	if (vma && (vma->vm_flags & VM_SOFTDIRTY))
1182 		flags2 = __PM_SOFT_DIRTY;
1183 	else
1184 		flags2 = 0;
1185 
1186 	for (; addr != end; addr += PAGE_SIZE) {
1187 		int offset = (addr & ~hmask) >> PAGE_SHIFT;
1188 		huge_pte_to_pagemap_entry(&pme, pm, *pte, offset, flags2);
1189 		err = add_to_pagemap(addr, &pme, pm);
1190 		if (err)
1191 			return err;
1192 	}
1193 
1194 	cond_resched();
1195 
1196 	return err;
1197 }
1198 #endif /* HUGETLB_PAGE */
1199 
1200 /*
1201  * /proc/pid/pagemap - an array mapping virtual pages to pfns
1202  *
1203  * For each page in the address space, this file contains one 64-bit entry
1204  * consisting of the following:
1205  *
1206  * Bits 0-54  page frame number (PFN) if present
1207  * Bits 0-4   swap type if swapped
1208  * Bits 5-54  swap offset if swapped
1209  * Bits 55-60 page shift (page size = 1<<page shift)
1210  * Bit  61    page is file-page or shared-anon
1211  * Bit  62    page swapped
1212  * Bit  63    page present
1213  *
1214  * If the page is not present but in swap, then the PFN contains an
1215  * encoding of the swap file number and the page's offset into the
1216  * swap. Unmapped pages return a null PFN. This allows determining
1217  * precisely which pages are mapped (or in swap) and comparing mapped
1218  * pages between processes.
1219  *
1220  * Efficient users of this interface will use /proc/pid/maps to
1221  * determine which areas of memory are actually mapped and llseek to
1222  * skip over unmapped regions.
1223  */
1224 static ssize_t pagemap_read(struct file *file, char __user *buf,
1225 			    size_t count, loff_t *ppos)
1226 {
1227 	struct task_struct *task = get_proc_task(file_inode(file));
1228 	struct mm_struct *mm;
1229 	struct pagemapread pm;
1230 	int ret = -ESRCH;
1231 	struct mm_walk pagemap_walk = {};
1232 	unsigned long src;
1233 	unsigned long svpfn;
1234 	unsigned long start_vaddr;
1235 	unsigned long end_vaddr;
1236 	int copied = 0;
1237 
1238 	if (!task)
1239 		goto out;
1240 
1241 	ret = -EINVAL;
1242 	/* file position must be aligned */
1243 	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
1244 		goto out_task;
1245 
1246 	ret = 0;
1247 	if (!count)
1248 		goto out_task;
1249 
1250 	pm.v2 = soft_dirty_cleared;
1251 	pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
1252 	pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
1253 	ret = -ENOMEM;
1254 	if (!pm.buffer)
1255 		goto out_task;
1256 
1257 	mm = mm_access(task, PTRACE_MODE_READ);
1258 	ret = PTR_ERR(mm);
1259 	if (!mm || IS_ERR(mm))
1260 		goto out_free;
1261 
1262 	pagemap_walk.pmd_entry = pagemap_pte_range;
1263 	pagemap_walk.pte_hole = pagemap_pte_hole;
1264 #ifdef CONFIG_HUGETLB_PAGE
1265 	pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
1266 #endif
1267 	pagemap_walk.mm = mm;
1268 	pagemap_walk.private = &pm;
1269 
1270 	src = *ppos;
1271 	svpfn = src / PM_ENTRY_BYTES;
1272 	start_vaddr = svpfn << PAGE_SHIFT;
1273 	end_vaddr = TASK_SIZE_OF(task);
1274 
1275 	/* watch out for wraparound */
1276 	if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT)
1277 		start_vaddr = end_vaddr;
1278 
1279 	/*
1280 	 * The odds are that this will stop walking way
1281 	 * before end_vaddr, because the length of the
1282 	 * user buffer is tracked in "pm", and the walk
1283 	 * will stop when we hit the end of the buffer.
1284 	 */
1285 	ret = 0;
1286 	while (count && (start_vaddr < end_vaddr)) {
1287 		int len;
1288 		unsigned long end;
1289 
1290 		pm.pos = 0;
1291 		end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
1292 		/* overflow ? */
1293 		if (end < start_vaddr || end > end_vaddr)
1294 			end = end_vaddr;
1295 		down_read(&mm->mmap_sem);
1296 		ret = walk_page_range(start_vaddr, end, &pagemap_walk);
1297 		up_read(&mm->mmap_sem);
1298 		start_vaddr = end;
1299 
1300 		len = min(count, PM_ENTRY_BYTES * pm.pos);
1301 		if (copy_to_user(buf, pm.buffer, len)) {
1302 			ret = -EFAULT;
1303 			goto out_mm;
1304 		}
1305 		copied += len;
1306 		buf += len;
1307 		count -= len;
1308 	}
1309 	*ppos += copied;
1310 	if (!ret || ret == PM_END_OF_BUFFER)
1311 		ret = copied;
1312 
1313 out_mm:
1314 	mmput(mm);
1315 out_free:
1316 	kfree(pm.buffer);
1317 out_task:
1318 	put_task_struct(task);
1319 out:
1320 	return ret;
1321 }
1322 
1323 static int pagemap_open(struct inode *inode, struct file *file)
1324 {
1325 	pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
1326 			"to stop being page-shift some time soon. See the "
1327 			"linux/Documentation/vm/pagemap.txt for details.\n");
1328 	return 0;
1329 }
1330 
1331 const struct file_operations proc_pagemap_operations = {
1332 	.llseek		= mem_lseek, /* borrow this */
1333 	.read		= pagemap_read,
1334 	.open		= pagemap_open,
1335 };
1336 #endif /* CONFIG_PROC_PAGE_MONITOR */
1337 
1338 #ifdef CONFIG_NUMA
1339 
1340 struct numa_maps {
1341 	struct vm_area_struct *vma;
1342 	unsigned long pages;
1343 	unsigned long anon;
1344 	unsigned long active;
1345 	unsigned long writeback;
1346 	unsigned long mapcount_max;
1347 	unsigned long dirty;
1348 	unsigned long swapcache;
1349 	unsigned long node[MAX_NUMNODES];
1350 };
1351 
1352 struct numa_maps_private {
1353 	struct proc_maps_private proc_maps;
1354 	struct numa_maps md;
1355 };
1356 
1357 static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
1358 			unsigned long nr_pages)
1359 {
1360 	int count = page_mapcount(page);
1361 
1362 	md->pages += nr_pages;
1363 	if (pte_dirty || PageDirty(page))
1364 		md->dirty += nr_pages;
1365 
1366 	if (PageSwapCache(page))
1367 		md->swapcache += nr_pages;
1368 
1369 	if (PageActive(page) || PageUnevictable(page))
1370 		md->active += nr_pages;
1371 
1372 	if (PageWriteback(page))
1373 		md->writeback += nr_pages;
1374 
1375 	if (PageAnon(page))
1376 		md->anon += nr_pages;
1377 
1378 	if (count > md->mapcount_max)
1379 		md->mapcount_max = count;
1380 
1381 	md->node[page_to_nid(page)] += nr_pages;
1382 }
1383 
1384 static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
1385 		unsigned long addr)
1386 {
1387 	struct page *page;
1388 	int nid;
1389 
1390 	if (!pte_present(pte))
1391 		return NULL;
1392 
1393 	page = vm_normal_page(vma, addr, pte);
1394 	if (!page)
1395 		return NULL;
1396 
1397 	if (PageReserved(page))
1398 		return NULL;
1399 
1400 	nid = page_to_nid(page);
1401 	if (!node_isset(nid, node_states[N_MEMORY]))
1402 		return NULL;
1403 
1404 	return page;
1405 }
1406 
1407 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
1408 		unsigned long end, struct mm_walk *walk)
1409 {
1410 	struct numa_maps *md;
1411 	spinlock_t *ptl;
1412 	pte_t *orig_pte;
1413 	pte_t *pte;
1414 
1415 	md = walk->private;
1416 
1417 	if (pmd_trans_huge_lock(pmd, md->vma, &ptl) == 1) {
1418 		pte_t huge_pte = *(pte_t *)pmd;
1419 		struct page *page;
1420 
1421 		page = can_gather_numa_stats(huge_pte, md->vma, addr);
1422 		if (page)
1423 			gather_stats(page, md, pte_dirty(huge_pte),
1424 				     HPAGE_PMD_SIZE/PAGE_SIZE);
1425 		spin_unlock(ptl);
1426 		return 0;
1427 	}
1428 
1429 	if (pmd_trans_unstable(pmd))
1430 		return 0;
1431 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
1432 	do {
1433 		struct page *page = can_gather_numa_stats(*pte, md->vma, addr);
1434 		if (!page)
1435 			continue;
1436 		gather_stats(page, md, pte_dirty(*pte), 1);
1437 
1438 	} while (pte++, addr += PAGE_SIZE, addr != end);
1439 	pte_unmap_unlock(orig_pte, ptl);
1440 	return 0;
1441 }
1442 #ifdef CONFIG_HUGETLB_PAGE
1443 static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
1444 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1445 {
1446 	struct numa_maps *md;
1447 	struct page *page;
1448 
1449 	if (!pte_present(*pte))
1450 		return 0;
1451 
1452 	page = pte_page(*pte);
1453 	if (!page)
1454 		return 0;
1455 
1456 	md = walk->private;
1457 	gather_stats(page, md, pte_dirty(*pte), 1);
1458 	return 0;
1459 }
1460 
1461 #else
1462 static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
1463 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1464 {
1465 	return 0;
1466 }
1467 #endif
1468 
1469 /*
1470  * Display pages allocated per node and memory policy via /proc.
1471  */
1472 static int show_numa_map(struct seq_file *m, void *v, int is_pid)
1473 {
1474 	struct numa_maps_private *numa_priv = m->private;
1475 	struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
1476 	struct vm_area_struct *vma = v;
1477 	struct numa_maps *md = &numa_priv->md;
1478 	struct file *file = vma->vm_file;
1479 	struct mm_struct *mm = vma->vm_mm;
1480 	struct mm_walk walk = {};
1481 	struct mempolicy *pol;
1482 	char buffer[64];
1483 	int nid;
1484 
1485 	if (!mm)
1486 		return 0;
1487 
1488 	/* Ensure we start with an empty set of numa_maps statistics. */
1489 	memset(md, 0, sizeof(*md));
1490 
1491 	md->vma = vma;
1492 
1493 	walk.hugetlb_entry = gather_hugetbl_stats;
1494 	walk.pmd_entry = gather_pte_stats;
1495 	walk.private = md;
1496 	walk.mm = mm;
1497 
1498 	pol = __get_vma_policy(vma, vma->vm_start);
1499 	if (pol) {
1500 		mpol_to_str(buffer, sizeof(buffer), pol);
1501 		mpol_cond_put(pol);
1502 	} else {
1503 		mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
1504 	}
1505 
1506 	seq_printf(m, "%08lx %s", vma->vm_start, buffer);
1507 
1508 	if (file) {
1509 		seq_puts(m, " file=");
1510 		seq_path(m, &file->f_path, "\n\t= ");
1511 	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
1512 		seq_puts(m, " heap");
1513 	} else {
1514 		pid_t tid = pid_of_stack(proc_priv, vma, is_pid);
1515 		if (tid != 0) {
1516 			/*
1517 			 * Thread stack in /proc/PID/task/TID/maps or
1518 			 * the main process stack.
1519 			 */
1520 			if (!is_pid || (vma->vm_start <= mm->start_stack &&
1521 			    vma->vm_end >= mm->start_stack))
1522 				seq_puts(m, " stack");
1523 			else
1524 				seq_printf(m, " stack:%d", tid);
1525 		}
1526 	}
1527 
1528 	if (is_vm_hugetlb_page(vma))
1529 		seq_puts(m, " huge");
1530 
1531 	walk_page_range(vma->vm_start, vma->vm_end, &walk);
1532 
1533 	if (!md->pages)
1534 		goto out;
1535 
1536 	if (md->anon)
1537 		seq_printf(m, " anon=%lu", md->anon);
1538 
1539 	if (md->dirty)
1540 		seq_printf(m, " dirty=%lu", md->dirty);
1541 
1542 	if (md->pages != md->anon && md->pages != md->dirty)
1543 		seq_printf(m, " mapped=%lu", md->pages);
1544 
1545 	if (md->mapcount_max > 1)
1546 		seq_printf(m, " mapmax=%lu", md->mapcount_max);
1547 
1548 	if (md->swapcache)
1549 		seq_printf(m, " swapcache=%lu", md->swapcache);
1550 
1551 	if (md->active < md->pages && !is_vm_hugetlb_page(vma))
1552 		seq_printf(m, " active=%lu", md->active);
1553 
1554 	if (md->writeback)
1555 		seq_printf(m, " writeback=%lu", md->writeback);
1556 
1557 	for_each_node_state(nid, N_MEMORY)
1558 		if (md->node[nid])
1559 			seq_printf(m, " N%d=%lu", nid, md->node[nid]);
1560 out:
1561 	seq_putc(m, '\n');
1562 	m_cache_vma(m, vma);
1563 	return 0;
1564 }
1565 
1566 static int show_pid_numa_map(struct seq_file *m, void *v)
1567 {
1568 	return show_numa_map(m, v, 1);
1569 }
1570 
1571 static int show_tid_numa_map(struct seq_file *m, void *v)
1572 {
1573 	return show_numa_map(m, v, 0);
1574 }
1575 
1576 static const struct seq_operations proc_pid_numa_maps_op = {
1577 	.start  = m_start,
1578 	.next   = m_next,
1579 	.stop   = m_stop,
1580 	.show   = show_pid_numa_map,
1581 };
1582 
1583 static const struct seq_operations proc_tid_numa_maps_op = {
1584 	.start  = m_start,
1585 	.next   = m_next,
1586 	.stop   = m_stop,
1587 	.show   = show_tid_numa_map,
1588 };
1589 
1590 static int numa_maps_open(struct inode *inode, struct file *file,
1591 			  const struct seq_operations *ops)
1592 {
1593 	return proc_maps_open(inode, file, ops,
1594 				sizeof(struct numa_maps_private));
1595 }
1596 
1597 static int pid_numa_maps_open(struct inode *inode, struct file *file)
1598 {
1599 	return numa_maps_open(inode, file, &proc_pid_numa_maps_op);
1600 }
1601 
1602 static int tid_numa_maps_open(struct inode *inode, struct file *file)
1603 {
1604 	return numa_maps_open(inode, file, &proc_tid_numa_maps_op);
1605 }
1606 
1607 const struct file_operations proc_pid_numa_maps_operations = {
1608 	.open		= pid_numa_maps_open,
1609 	.read		= seq_read,
1610 	.llseek		= seq_lseek,
1611 	.release	= proc_map_release,
1612 };
1613 
1614 const struct file_operations proc_tid_numa_maps_operations = {
1615 	.open		= tid_numa_maps_open,
1616 	.read		= seq_read,
1617 	.llseek		= seq_lseek,
1618 	.release	= proc_map_release,
1619 };
1620 #endif /* CONFIG_NUMA */
1621