xref: /openbmc/linux/fs/proc/task_mmu.c (revision 2572f00d)
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 #include <linux/page_idle.h>
17 
18 #include <asm/elf.h>
19 #include <asm/uaccess.h>
20 #include <asm/tlbflush.h>
21 #include "internal.h"
22 
23 void task_mem(struct seq_file *m, struct mm_struct *mm)
24 {
25 	unsigned long data, text, lib, swap, ptes, pmds;
26 	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
27 
28 	/*
29 	 * Note: to minimize their overhead, mm maintains hiwater_vm and
30 	 * hiwater_rss only when about to *lower* total_vm or rss.  Any
31 	 * collector of these hiwater stats must therefore get total_vm
32 	 * and rss too, which will usually be the higher.  Barriers? not
33 	 * worth the effort, such snapshots can always be inconsistent.
34 	 */
35 	hiwater_vm = total_vm = mm->total_vm;
36 	if (hiwater_vm < mm->hiwater_vm)
37 		hiwater_vm = mm->hiwater_vm;
38 	hiwater_rss = total_rss = get_mm_rss(mm);
39 	if (hiwater_rss < mm->hiwater_rss)
40 		hiwater_rss = mm->hiwater_rss;
41 
42 	data = mm->total_vm - mm->shared_vm - mm->stack_vm;
43 	text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
44 	lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
45 	swap = get_mm_counter(mm, MM_SWAPENTS);
46 	ptes = PTRS_PER_PTE * sizeof(pte_t) * atomic_long_read(&mm->nr_ptes);
47 	pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm);
48 	seq_printf(m,
49 		"VmPeak:\t%8lu kB\n"
50 		"VmSize:\t%8lu kB\n"
51 		"VmLck:\t%8lu kB\n"
52 		"VmPin:\t%8lu kB\n"
53 		"VmHWM:\t%8lu kB\n"
54 		"VmRSS:\t%8lu kB\n"
55 		"VmData:\t%8lu kB\n"
56 		"VmStk:\t%8lu kB\n"
57 		"VmExe:\t%8lu kB\n"
58 		"VmLib:\t%8lu kB\n"
59 		"VmPTE:\t%8lu kB\n"
60 		"VmPMD:\t%8lu kB\n"
61 		"VmSwap:\t%8lu kB\n",
62 		hiwater_vm << (PAGE_SHIFT-10),
63 		total_vm << (PAGE_SHIFT-10),
64 		mm->locked_vm << (PAGE_SHIFT-10),
65 		mm->pinned_vm << (PAGE_SHIFT-10),
66 		hiwater_rss << (PAGE_SHIFT-10),
67 		total_rss << (PAGE_SHIFT-10),
68 		data << (PAGE_SHIFT-10),
69 		mm->stack_vm << (PAGE_SHIFT-10), text, lib,
70 		ptes >> 10,
71 		pmds >> 10,
72 		swap << (PAGE_SHIFT-10));
73 	hugetlb_report_usage(m, mm);
74 }
75 
76 unsigned long task_vsize(struct mm_struct *mm)
77 {
78 	return PAGE_SIZE * mm->total_vm;
79 }
80 
81 unsigned long task_statm(struct mm_struct *mm,
82 			 unsigned long *shared, unsigned long *text,
83 			 unsigned long *data, unsigned long *resident)
84 {
85 	*shared = get_mm_counter(mm, MM_FILEPAGES);
86 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
87 								>> PAGE_SHIFT;
88 	*data = mm->total_vm - mm->shared_vm;
89 	*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
90 	return mm->total_vm;
91 }
92 
93 #ifdef CONFIG_NUMA
94 /*
95  * Save get_task_policy() for show_numa_map().
96  */
97 static void hold_task_mempolicy(struct proc_maps_private *priv)
98 {
99 	struct task_struct *task = priv->task;
100 
101 	task_lock(task);
102 	priv->task_mempolicy = get_task_policy(task);
103 	mpol_get(priv->task_mempolicy);
104 	task_unlock(task);
105 }
106 static void release_task_mempolicy(struct proc_maps_private *priv)
107 {
108 	mpol_put(priv->task_mempolicy);
109 }
110 #else
111 static void hold_task_mempolicy(struct proc_maps_private *priv)
112 {
113 }
114 static void release_task_mempolicy(struct proc_maps_private *priv)
115 {
116 }
117 #endif
118 
119 static void vma_stop(struct proc_maps_private *priv)
120 {
121 	struct mm_struct *mm = priv->mm;
122 
123 	release_task_mempolicy(priv);
124 	up_read(&mm->mmap_sem);
125 	mmput(mm);
126 }
127 
128 static struct vm_area_struct *
129 m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
130 {
131 	if (vma == priv->tail_vma)
132 		return NULL;
133 	return vma->vm_next ?: priv->tail_vma;
134 }
135 
136 static void m_cache_vma(struct seq_file *m, struct vm_area_struct *vma)
137 {
138 	if (m->count < m->size)	/* vma is copied successfully */
139 		m->version = m_next_vma(m->private, vma) ? vma->vm_start : -1UL;
140 }
141 
142 static void *m_start(struct seq_file *m, loff_t *ppos)
143 {
144 	struct proc_maps_private *priv = m->private;
145 	unsigned long last_addr = m->version;
146 	struct mm_struct *mm;
147 	struct vm_area_struct *vma;
148 	unsigned int pos = *ppos;
149 
150 	/* See m_cache_vma(). Zero at the start or after lseek. */
151 	if (last_addr == -1UL)
152 		return NULL;
153 
154 	priv->task = get_proc_task(priv->inode);
155 	if (!priv->task)
156 		return ERR_PTR(-ESRCH);
157 
158 	mm = priv->mm;
159 	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
160 		return NULL;
161 
162 	down_read(&mm->mmap_sem);
163 	hold_task_mempolicy(priv);
164 	priv->tail_vma = get_gate_vma(mm);
165 
166 	if (last_addr) {
167 		vma = find_vma(mm, last_addr);
168 		if (vma && (vma = m_next_vma(priv, vma)))
169 			return vma;
170 	}
171 
172 	m->version = 0;
173 	if (pos < mm->map_count) {
174 		for (vma = mm->mmap; pos; pos--) {
175 			m->version = vma->vm_start;
176 			vma = vma->vm_next;
177 		}
178 		return vma;
179 	}
180 
181 	/* we do not bother to update m->version in this case */
182 	if (pos == mm->map_count && priv->tail_vma)
183 		return priv->tail_vma;
184 
185 	vma_stop(priv);
186 	return NULL;
187 }
188 
189 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
190 {
191 	struct proc_maps_private *priv = m->private;
192 	struct vm_area_struct *next;
193 
194 	(*pos)++;
195 	next = m_next_vma(priv, v);
196 	if (!next)
197 		vma_stop(priv);
198 	return next;
199 }
200 
201 static void m_stop(struct seq_file *m, void *v)
202 {
203 	struct proc_maps_private *priv = m->private;
204 
205 	if (!IS_ERR_OR_NULL(v))
206 		vma_stop(priv);
207 	if (priv->task) {
208 		put_task_struct(priv->task);
209 		priv->task = NULL;
210 	}
211 }
212 
213 static int proc_maps_open(struct inode *inode, struct file *file,
214 			const struct seq_operations *ops, int psize)
215 {
216 	struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
217 
218 	if (!priv)
219 		return -ENOMEM;
220 
221 	priv->inode = inode;
222 	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
223 	if (IS_ERR(priv->mm)) {
224 		int err = PTR_ERR(priv->mm);
225 
226 		seq_release_private(inode, file);
227 		return err;
228 	}
229 
230 	return 0;
231 }
232 
233 static int proc_map_release(struct inode *inode, struct file *file)
234 {
235 	struct seq_file *seq = file->private_data;
236 	struct proc_maps_private *priv = seq->private;
237 
238 	if (priv->mm)
239 		mmdrop(priv->mm);
240 
241 	return seq_release_private(inode, file);
242 }
243 
244 static int do_maps_open(struct inode *inode, struct file *file,
245 			const struct seq_operations *ops)
246 {
247 	return proc_maps_open(inode, file, ops,
248 				sizeof(struct proc_maps_private));
249 }
250 
251 static pid_t pid_of_stack(struct proc_maps_private *priv,
252 				struct vm_area_struct *vma, bool is_pid)
253 {
254 	struct inode *inode = priv->inode;
255 	struct task_struct *task;
256 	pid_t ret = 0;
257 
258 	rcu_read_lock();
259 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
260 	if (task) {
261 		task = task_of_stack(task, vma, is_pid);
262 		if (task)
263 			ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);
264 	}
265 	rcu_read_unlock();
266 
267 	return ret;
268 }
269 
270 static void
271 show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
272 {
273 	struct mm_struct *mm = vma->vm_mm;
274 	struct file *file = vma->vm_file;
275 	struct proc_maps_private *priv = m->private;
276 	vm_flags_t flags = vma->vm_flags;
277 	unsigned long ino = 0;
278 	unsigned long long pgoff = 0;
279 	unsigned long start, end;
280 	dev_t dev = 0;
281 	const char *name = NULL;
282 
283 	if (file) {
284 		struct inode *inode = file_inode(vma->vm_file);
285 		dev = inode->i_sb->s_dev;
286 		ino = inode->i_ino;
287 		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
288 	}
289 
290 	/* We don't show the stack guard page in /proc/maps */
291 	start = vma->vm_start;
292 	if (stack_guard_page_start(vma, start))
293 		start += PAGE_SIZE;
294 	end = vma->vm_end;
295 	if (stack_guard_page_end(vma, end))
296 		end -= PAGE_SIZE;
297 
298 	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
299 	seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
300 			start,
301 			end,
302 			flags & VM_READ ? 'r' : '-',
303 			flags & VM_WRITE ? 'w' : '-',
304 			flags & VM_EXEC ? 'x' : '-',
305 			flags & VM_MAYSHARE ? 's' : 'p',
306 			pgoff,
307 			MAJOR(dev), MINOR(dev), ino);
308 
309 	/*
310 	 * Print the dentry name for named mappings, and a
311 	 * special [heap] marker for the heap:
312 	 */
313 	if (file) {
314 		seq_pad(m, ' ');
315 		seq_file_path(m, file, "\n");
316 		goto done;
317 	}
318 
319 	if (vma->vm_ops && vma->vm_ops->name) {
320 		name = vma->vm_ops->name(vma);
321 		if (name)
322 			goto done;
323 	}
324 
325 	name = arch_vma_name(vma);
326 	if (!name) {
327 		pid_t tid;
328 
329 		if (!mm) {
330 			name = "[vdso]";
331 			goto done;
332 		}
333 
334 		if (vma->vm_start <= mm->brk &&
335 		    vma->vm_end >= mm->start_brk) {
336 			name = "[heap]";
337 			goto done;
338 		}
339 
340 		tid = pid_of_stack(priv, vma, is_pid);
341 		if (tid != 0) {
342 			/*
343 			 * Thread stack in /proc/PID/task/TID/maps or
344 			 * the main process stack.
345 			 */
346 			if (!is_pid || (vma->vm_start <= mm->start_stack &&
347 			    vma->vm_end >= mm->start_stack)) {
348 				name = "[stack]";
349 			} else {
350 				/* Thread stack in /proc/PID/maps */
351 				seq_pad(m, ' ');
352 				seq_printf(m, "[stack:%d]", tid);
353 			}
354 		}
355 	}
356 
357 done:
358 	if (name) {
359 		seq_pad(m, ' ');
360 		seq_puts(m, name);
361 	}
362 	seq_putc(m, '\n');
363 }
364 
365 static int show_map(struct seq_file *m, void *v, int is_pid)
366 {
367 	show_map_vma(m, v, is_pid);
368 	m_cache_vma(m, v);
369 	return 0;
370 }
371 
372 static int show_pid_map(struct seq_file *m, void *v)
373 {
374 	return show_map(m, v, 1);
375 }
376 
377 static int show_tid_map(struct seq_file *m, void *v)
378 {
379 	return show_map(m, v, 0);
380 }
381 
382 static const struct seq_operations proc_pid_maps_op = {
383 	.start	= m_start,
384 	.next	= m_next,
385 	.stop	= m_stop,
386 	.show	= show_pid_map
387 };
388 
389 static const struct seq_operations proc_tid_maps_op = {
390 	.start	= m_start,
391 	.next	= m_next,
392 	.stop	= m_stop,
393 	.show	= show_tid_map
394 };
395 
396 static int pid_maps_open(struct inode *inode, struct file *file)
397 {
398 	return do_maps_open(inode, file, &proc_pid_maps_op);
399 }
400 
401 static int tid_maps_open(struct inode *inode, struct file *file)
402 {
403 	return do_maps_open(inode, file, &proc_tid_maps_op);
404 }
405 
406 const struct file_operations proc_pid_maps_operations = {
407 	.open		= pid_maps_open,
408 	.read		= seq_read,
409 	.llseek		= seq_lseek,
410 	.release	= proc_map_release,
411 };
412 
413 const struct file_operations proc_tid_maps_operations = {
414 	.open		= tid_maps_open,
415 	.read		= seq_read,
416 	.llseek		= seq_lseek,
417 	.release	= proc_map_release,
418 };
419 
420 /*
421  * Proportional Set Size(PSS): my share of RSS.
422  *
423  * PSS of a process is the count of pages it has in memory, where each
424  * page is divided by the number of processes sharing it.  So if a
425  * process has 1000 pages all to itself, and 1000 shared with one other
426  * process, its PSS will be 1500.
427  *
428  * To keep (accumulated) division errors low, we adopt a 64bit
429  * fixed-point pss counter to minimize division errors. So (pss >>
430  * PSS_SHIFT) would be the real byte count.
431  *
432  * A shift of 12 before division means (assuming 4K page size):
433  * 	- 1M 3-user-pages add up to 8KB errors;
434  * 	- supports mapcount up to 2^24, or 16M;
435  * 	- supports PSS up to 2^52 bytes, or 4PB.
436  */
437 #define PSS_SHIFT 12
438 
439 #ifdef CONFIG_PROC_PAGE_MONITOR
440 struct mem_size_stats {
441 	unsigned long resident;
442 	unsigned long shared_clean;
443 	unsigned long shared_dirty;
444 	unsigned long private_clean;
445 	unsigned long private_dirty;
446 	unsigned long referenced;
447 	unsigned long anonymous;
448 	unsigned long anonymous_thp;
449 	unsigned long swap;
450 	unsigned long shared_hugetlb;
451 	unsigned long private_hugetlb;
452 	u64 pss;
453 	u64 swap_pss;
454 };
455 
456 static void smaps_account(struct mem_size_stats *mss, struct page *page,
457 		unsigned long size, bool young, bool dirty)
458 {
459 	int mapcount;
460 
461 	if (PageAnon(page))
462 		mss->anonymous += size;
463 
464 	mss->resident += size;
465 	/* Accumulate the size in pages that have been accessed. */
466 	if (young || page_is_young(page) || PageReferenced(page))
467 		mss->referenced += size;
468 	mapcount = page_mapcount(page);
469 	if (mapcount >= 2) {
470 		u64 pss_delta;
471 
472 		if (dirty || PageDirty(page))
473 			mss->shared_dirty += size;
474 		else
475 			mss->shared_clean += size;
476 		pss_delta = (u64)size << PSS_SHIFT;
477 		do_div(pss_delta, mapcount);
478 		mss->pss += pss_delta;
479 	} else {
480 		if (dirty || PageDirty(page))
481 			mss->private_dirty += size;
482 		else
483 			mss->private_clean += size;
484 		mss->pss += (u64)size << PSS_SHIFT;
485 	}
486 }
487 
488 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
489 		struct mm_walk *walk)
490 {
491 	struct mem_size_stats *mss = walk->private;
492 	struct vm_area_struct *vma = walk->vma;
493 	struct page *page = NULL;
494 
495 	if (pte_present(*pte)) {
496 		page = vm_normal_page(vma, addr, *pte);
497 	} else if (is_swap_pte(*pte)) {
498 		swp_entry_t swpent = pte_to_swp_entry(*pte);
499 
500 		if (!non_swap_entry(swpent)) {
501 			int mapcount;
502 
503 			mss->swap += PAGE_SIZE;
504 			mapcount = swp_swapcount(swpent);
505 			if (mapcount >= 2) {
506 				u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
507 
508 				do_div(pss_delta, mapcount);
509 				mss->swap_pss += pss_delta;
510 			} else {
511 				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
512 			}
513 		} else if (is_migration_entry(swpent))
514 			page = migration_entry_to_page(swpent);
515 	}
516 
517 	if (!page)
518 		return;
519 	smaps_account(mss, page, PAGE_SIZE, pte_young(*pte), pte_dirty(*pte));
520 }
521 
522 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
523 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
524 		struct mm_walk *walk)
525 {
526 	struct mem_size_stats *mss = walk->private;
527 	struct vm_area_struct *vma = walk->vma;
528 	struct page *page;
529 
530 	/* FOLL_DUMP will return -EFAULT on huge zero page */
531 	page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
532 	if (IS_ERR_OR_NULL(page))
533 		return;
534 	mss->anonymous_thp += HPAGE_PMD_SIZE;
535 	smaps_account(mss, page, HPAGE_PMD_SIZE,
536 			pmd_young(*pmd), pmd_dirty(*pmd));
537 }
538 #else
539 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
540 		struct mm_walk *walk)
541 {
542 }
543 #endif
544 
545 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
546 			   struct mm_walk *walk)
547 {
548 	struct vm_area_struct *vma = walk->vma;
549 	pte_t *pte;
550 	spinlock_t *ptl;
551 
552 	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
553 		smaps_pmd_entry(pmd, addr, walk);
554 		spin_unlock(ptl);
555 		return 0;
556 	}
557 
558 	if (pmd_trans_unstable(pmd))
559 		return 0;
560 	/*
561 	 * The mmap_sem held all the way back in m_start() is what
562 	 * keeps khugepaged out of here and from collapsing things
563 	 * in here.
564 	 */
565 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
566 	for (; addr != end; pte++, addr += PAGE_SIZE)
567 		smaps_pte_entry(pte, addr, walk);
568 	pte_unmap_unlock(pte - 1, ptl);
569 	cond_resched();
570 	return 0;
571 }
572 
573 static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
574 {
575 	/*
576 	 * Don't forget to update Documentation/ on changes.
577 	 */
578 	static const char mnemonics[BITS_PER_LONG][2] = {
579 		/*
580 		 * In case if we meet a flag we don't know about.
581 		 */
582 		[0 ... (BITS_PER_LONG-1)] = "??",
583 
584 		[ilog2(VM_READ)]	= "rd",
585 		[ilog2(VM_WRITE)]	= "wr",
586 		[ilog2(VM_EXEC)]	= "ex",
587 		[ilog2(VM_SHARED)]	= "sh",
588 		[ilog2(VM_MAYREAD)]	= "mr",
589 		[ilog2(VM_MAYWRITE)]	= "mw",
590 		[ilog2(VM_MAYEXEC)]	= "me",
591 		[ilog2(VM_MAYSHARE)]	= "ms",
592 		[ilog2(VM_GROWSDOWN)]	= "gd",
593 		[ilog2(VM_PFNMAP)]	= "pf",
594 		[ilog2(VM_DENYWRITE)]	= "dw",
595 #ifdef CONFIG_X86_INTEL_MPX
596 		[ilog2(VM_MPX)]		= "mp",
597 #endif
598 		[ilog2(VM_LOCKED)]	= "lo",
599 		[ilog2(VM_IO)]		= "io",
600 		[ilog2(VM_SEQ_READ)]	= "sr",
601 		[ilog2(VM_RAND_READ)]	= "rr",
602 		[ilog2(VM_DONTCOPY)]	= "dc",
603 		[ilog2(VM_DONTEXPAND)]	= "de",
604 		[ilog2(VM_ACCOUNT)]	= "ac",
605 		[ilog2(VM_NORESERVE)]	= "nr",
606 		[ilog2(VM_HUGETLB)]	= "ht",
607 		[ilog2(VM_ARCH_1)]	= "ar",
608 		[ilog2(VM_DONTDUMP)]	= "dd",
609 #ifdef CONFIG_MEM_SOFT_DIRTY
610 		[ilog2(VM_SOFTDIRTY)]	= "sd",
611 #endif
612 		[ilog2(VM_MIXEDMAP)]	= "mm",
613 		[ilog2(VM_HUGEPAGE)]	= "hg",
614 		[ilog2(VM_NOHUGEPAGE)]	= "nh",
615 		[ilog2(VM_MERGEABLE)]	= "mg",
616 		[ilog2(VM_UFFD_MISSING)]= "um",
617 		[ilog2(VM_UFFD_WP)]	= "uw",
618 	};
619 	size_t i;
620 
621 	seq_puts(m, "VmFlags: ");
622 	for (i = 0; i < BITS_PER_LONG; i++) {
623 		if (vma->vm_flags & (1UL << i)) {
624 			seq_printf(m, "%c%c ",
625 				   mnemonics[i][0], mnemonics[i][1]);
626 		}
627 	}
628 	seq_putc(m, '\n');
629 }
630 
631 #ifdef CONFIG_HUGETLB_PAGE
632 static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
633 				 unsigned long addr, unsigned long end,
634 				 struct mm_walk *walk)
635 {
636 	struct mem_size_stats *mss = walk->private;
637 	struct vm_area_struct *vma = walk->vma;
638 	struct page *page = NULL;
639 
640 	if (pte_present(*pte)) {
641 		page = vm_normal_page(vma, addr, *pte);
642 	} else if (is_swap_pte(*pte)) {
643 		swp_entry_t swpent = pte_to_swp_entry(*pte);
644 
645 		if (is_migration_entry(swpent))
646 			page = migration_entry_to_page(swpent);
647 	}
648 	if (page) {
649 		int mapcount = page_mapcount(page);
650 
651 		if (mapcount >= 2)
652 			mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
653 		else
654 			mss->private_hugetlb += huge_page_size(hstate_vma(vma));
655 	}
656 	return 0;
657 }
658 #endif /* HUGETLB_PAGE */
659 
660 static int show_smap(struct seq_file *m, void *v, int is_pid)
661 {
662 	struct vm_area_struct *vma = v;
663 	struct mem_size_stats mss;
664 	struct mm_walk smaps_walk = {
665 		.pmd_entry = smaps_pte_range,
666 #ifdef CONFIG_HUGETLB_PAGE
667 		.hugetlb_entry = smaps_hugetlb_range,
668 #endif
669 		.mm = vma->vm_mm,
670 		.private = &mss,
671 	};
672 
673 	memset(&mss, 0, sizeof mss);
674 	/* mmap_sem is held in m_start */
675 	walk_page_vma(vma, &smaps_walk);
676 
677 	show_map_vma(m, vma, is_pid);
678 
679 	seq_printf(m,
680 		   "Size:           %8lu kB\n"
681 		   "Rss:            %8lu kB\n"
682 		   "Pss:            %8lu kB\n"
683 		   "Shared_Clean:   %8lu kB\n"
684 		   "Shared_Dirty:   %8lu kB\n"
685 		   "Private_Clean:  %8lu kB\n"
686 		   "Private_Dirty:  %8lu kB\n"
687 		   "Referenced:     %8lu kB\n"
688 		   "Anonymous:      %8lu kB\n"
689 		   "AnonHugePages:  %8lu kB\n"
690 		   "Shared_Hugetlb: %8lu kB\n"
691 		   "Private_Hugetlb: %7lu kB\n"
692 		   "Swap:           %8lu kB\n"
693 		   "SwapPss:        %8lu kB\n"
694 		   "KernelPageSize: %8lu kB\n"
695 		   "MMUPageSize:    %8lu kB\n"
696 		   "Locked:         %8lu kB\n",
697 		   (vma->vm_end - vma->vm_start) >> 10,
698 		   mss.resident >> 10,
699 		   (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
700 		   mss.shared_clean  >> 10,
701 		   mss.shared_dirty  >> 10,
702 		   mss.private_clean >> 10,
703 		   mss.private_dirty >> 10,
704 		   mss.referenced >> 10,
705 		   mss.anonymous >> 10,
706 		   mss.anonymous_thp >> 10,
707 		   mss.shared_hugetlb >> 10,
708 		   mss.private_hugetlb >> 10,
709 		   mss.swap >> 10,
710 		   (unsigned long)(mss.swap_pss >> (10 + PSS_SHIFT)),
711 		   vma_kernel_pagesize(vma) >> 10,
712 		   vma_mmu_pagesize(vma) >> 10,
713 		   (vma->vm_flags & VM_LOCKED) ?
714 			(unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
715 
716 	show_smap_vma_flags(m, vma);
717 	m_cache_vma(m, vma);
718 	return 0;
719 }
720 
721 static int show_pid_smap(struct seq_file *m, void *v)
722 {
723 	return show_smap(m, v, 1);
724 }
725 
726 static int show_tid_smap(struct seq_file *m, void *v)
727 {
728 	return show_smap(m, v, 0);
729 }
730 
731 static const struct seq_operations proc_pid_smaps_op = {
732 	.start	= m_start,
733 	.next	= m_next,
734 	.stop	= m_stop,
735 	.show	= show_pid_smap
736 };
737 
738 static const struct seq_operations proc_tid_smaps_op = {
739 	.start	= m_start,
740 	.next	= m_next,
741 	.stop	= m_stop,
742 	.show	= show_tid_smap
743 };
744 
745 static int pid_smaps_open(struct inode *inode, struct file *file)
746 {
747 	return do_maps_open(inode, file, &proc_pid_smaps_op);
748 }
749 
750 static int tid_smaps_open(struct inode *inode, struct file *file)
751 {
752 	return do_maps_open(inode, file, &proc_tid_smaps_op);
753 }
754 
755 const struct file_operations proc_pid_smaps_operations = {
756 	.open		= pid_smaps_open,
757 	.read		= seq_read,
758 	.llseek		= seq_lseek,
759 	.release	= proc_map_release,
760 };
761 
762 const struct file_operations proc_tid_smaps_operations = {
763 	.open		= tid_smaps_open,
764 	.read		= seq_read,
765 	.llseek		= seq_lseek,
766 	.release	= proc_map_release,
767 };
768 
769 enum clear_refs_types {
770 	CLEAR_REFS_ALL = 1,
771 	CLEAR_REFS_ANON,
772 	CLEAR_REFS_MAPPED,
773 	CLEAR_REFS_SOFT_DIRTY,
774 	CLEAR_REFS_MM_HIWATER_RSS,
775 	CLEAR_REFS_LAST,
776 };
777 
778 struct clear_refs_private {
779 	enum clear_refs_types type;
780 };
781 
782 #ifdef CONFIG_MEM_SOFT_DIRTY
783 static inline void clear_soft_dirty(struct vm_area_struct *vma,
784 		unsigned long addr, pte_t *pte)
785 {
786 	/*
787 	 * The soft-dirty tracker uses #PF-s to catch writes
788 	 * to pages, so write-protect the pte as well. See the
789 	 * Documentation/vm/soft-dirty.txt for full description
790 	 * of how soft-dirty works.
791 	 */
792 	pte_t ptent = *pte;
793 
794 	if (pte_present(ptent)) {
795 		ptent = ptep_modify_prot_start(vma->vm_mm, addr, pte);
796 		ptent = pte_wrprotect(ptent);
797 		ptent = pte_clear_soft_dirty(ptent);
798 		ptep_modify_prot_commit(vma->vm_mm, addr, pte, ptent);
799 	} else if (is_swap_pte(ptent)) {
800 		ptent = pte_swp_clear_soft_dirty(ptent);
801 		set_pte_at(vma->vm_mm, addr, pte, ptent);
802 	}
803 }
804 #else
805 static inline void clear_soft_dirty(struct vm_area_struct *vma,
806 		unsigned long addr, pte_t *pte)
807 {
808 }
809 #endif
810 
811 #if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
812 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
813 		unsigned long addr, pmd_t *pmdp)
814 {
815 	pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
816 
817 	pmd = pmd_wrprotect(pmd);
818 	pmd = pmd_clear_soft_dirty(pmd);
819 
820 	if (vma->vm_flags & VM_SOFTDIRTY)
821 		vma->vm_flags &= ~VM_SOFTDIRTY;
822 
823 	set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
824 }
825 #else
826 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
827 		unsigned long addr, pmd_t *pmdp)
828 {
829 }
830 #endif
831 
832 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
833 				unsigned long end, struct mm_walk *walk)
834 {
835 	struct clear_refs_private *cp = walk->private;
836 	struct vm_area_struct *vma = walk->vma;
837 	pte_t *pte, ptent;
838 	spinlock_t *ptl;
839 	struct page *page;
840 
841 	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
842 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
843 			clear_soft_dirty_pmd(vma, addr, pmd);
844 			goto out;
845 		}
846 
847 		page = pmd_page(*pmd);
848 
849 		/* Clear accessed and referenced bits. */
850 		pmdp_test_and_clear_young(vma, addr, pmd);
851 		test_and_clear_page_young(page);
852 		ClearPageReferenced(page);
853 out:
854 		spin_unlock(ptl);
855 		return 0;
856 	}
857 
858 	if (pmd_trans_unstable(pmd))
859 		return 0;
860 
861 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
862 	for (; addr != end; pte++, addr += PAGE_SIZE) {
863 		ptent = *pte;
864 
865 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
866 			clear_soft_dirty(vma, addr, pte);
867 			continue;
868 		}
869 
870 		if (!pte_present(ptent))
871 			continue;
872 
873 		page = vm_normal_page(vma, addr, ptent);
874 		if (!page)
875 			continue;
876 
877 		/* Clear accessed and referenced bits. */
878 		ptep_test_and_clear_young(vma, addr, pte);
879 		test_and_clear_page_young(page);
880 		ClearPageReferenced(page);
881 	}
882 	pte_unmap_unlock(pte - 1, ptl);
883 	cond_resched();
884 	return 0;
885 }
886 
887 static int clear_refs_test_walk(unsigned long start, unsigned long end,
888 				struct mm_walk *walk)
889 {
890 	struct clear_refs_private *cp = walk->private;
891 	struct vm_area_struct *vma = walk->vma;
892 
893 	if (vma->vm_flags & VM_PFNMAP)
894 		return 1;
895 
896 	/*
897 	 * Writing 1 to /proc/pid/clear_refs affects all pages.
898 	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
899 	 * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
900 	 * Writing 4 to /proc/pid/clear_refs affects all pages.
901 	 */
902 	if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
903 		return 1;
904 	if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
905 		return 1;
906 	return 0;
907 }
908 
909 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
910 				size_t count, loff_t *ppos)
911 {
912 	struct task_struct *task;
913 	char buffer[PROC_NUMBUF];
914 	struct mm_struct *mm;
915 	struct vm_area_struct *vma;
916 	enum clear_refs_types type;
917 	int itype;
918 	int rv;
919 
920 	memset(buffer, 0, sizeof(buffer));
921 	if (count > sizeof(buffer) - 1)
922 		count = sizeof(buffer) - 1;
923 	if (copy_from_user(buffer, buf, count))
924 		return -EFAULT;
925 	rv = kstrtoint(strstrip(buffer), 10, &itype);
926 	if (rv < 0)
927 		return rv;
928 	type = (enum clear_refs_types)itype;
929 	if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
930 		return -EINVAL;
931 
932 	task = get_proc_task(file_inode(file));
933 	if (!task)
934 		return -ESRCH;
935 	mm = get_task_mm(task);
936 	if (mm) {
937 		struct clear_refs_private cp = {
938 			.type = type,
939 		};
940 		struct mm_walk clear_refs_walk = {
941 			.pmd_entry = clear_refs_pte_range,
942 			.test_walk = clear_refs_test_walk,
943 			.mm = mm,
944 			.private = &cp,
945 		};
946 
947 		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
948 			/*
949 			 * Writing 5 to /proc/pid/clear_refs resets the peak
950 			 * resident set size to this mm's current rss value.
951 			 */
952 			down_write(&mm->mmap_sem);
953 			reset_mm_hiwater_rss(mm);
954 			up_write(&mm->mmap_sem);
955 			goto out_mm;
956 		}
957 
958 		down_read(&mm->mmap_sem);
959 		if (type == CLEAR_REFS_SOFT_DIRTY) {
960 			for (vma = mm->mmap; vma; vma = vma->vm_next) {
961 				if (!(vma->vm_flags & VM_SOFTDIRTY))
962 					continue;
963 				up_read(&mm->mmap_sem);
964 				down_write(&mm->mmap_sem);
965 				for (vma = mm->mmap; vma; vma = vma->vm_next) {
966 					vma->vm_flags &= ~VM_SOFTDIRTY;
967 					vma_set_page_prot(vma);
968 				}
969 				downgrade_write(&mm->mmap_sem);
970 				break;
971 			}
972 			mmu_notifier_invalidate_range_start(mm, 0, -1);
973 		}
974 		walk_page_range(0, ~0UL, &clear_refs_walk);
975 		if (type == CLEAR_REFS_SOFT_DIRTY)
976 			mmu_notifier_invalidate_range_end(mm, 0, -1);
977 		flush_tlb_mm(mm);
978 		up_read(&mm->mmap_sem);
979 out_mm:
980 		mmput(mm);
981 	}
982 	put_task_struct(task);
983 
984 	return count;
985 }
986 
987 const struct file_operations proc_clear_refs_operations = {
988 	.write		= clear_refs_write,
989 	.llseek		= noop_llseek,
990 };
991 
992 typedef struct {
993 	u64 pme;
994 } pagemap_entry_t;
995 
996 struct pagemapread {
997 	int pos, len;		/* units: PM_ENTRY_BYTES, not bytes */
998 	pagemap_entry_t *buffer;
999 	bool show_pfn;
1000 };
1001 
1002 #define PAGEMAP_WALK_SIZE	(PMD_SIZE)
1003 #define PAGEMAP_WALK_MASK	(PMD_MASK)
1004 
1005 #define PM_ENTRY_BYTES		sizeof(pagemap_entry_t)
1006 #define PM_PFRAME_BITS		55
1007 #define PM_PFRAME_MASK		GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
1008 #define PM_SOFT_DIRTY		BIT_ULL(55)
1009 #define PM_MMAP_EXCLUSIVE	BIT_ULL(56)
1010 #define PM_FILE			BIT_ULL(61)
1011 #define PM_SWAP			BIT_ULL(62)
1012 #define PM_PRESENT		BIT_ULL(63)
1013 
1014 #define PM_END_OF_BUFFER    1
1015 
1016 static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
1017 {
1018 	return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
1019 }
1020 
1021 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
1022 			  struct pagemapread *pm)
1023 {
1024 	pm->buffer[pm->pos++] = *pme;
1025 	if (pm->pos >= pm->len)
1026 		return PM_END_OF_BUFFER;
1027 	return 0;
1028 }
1029 
1030 static int pagemap_pte_hole(unsigned long start, unsigned long end,
1031 				struct mm_walk *walk)
1032 {
1033 	struct pagemapread *pm = walk->private;
1034 	unsigned long addr = start;
1035 	int err = 0;
1036 
1037 	while (addr < end) {
1038 		struct vm_area_struct *vma = find_vma(walk->mm, addr);
1039 		pagemap_entry_t pme = make_pme(0, 0);
1040 		/* End of address space hole, which we mark as non-present. */
1041 		unsigned long hole_end;
1042 
1043 		if (vma)
1044 			hole_end = min(end, vma->vm_start);
1045 		else
1046 			hole_end = end;
1047 
1048 		for (; addr < hole_end; addr += PAGE_SIZE) {
1049 			err = add_to_pagemap(addr, &pme, pm);
1050 			if (err)
1051 				goto out;
1052 		}
1053 
1054 		if (!vma)
1055 			break;
1056 
1057 		/* Addresses in the VMA. */
1058 		if (vma->vm_flags & VM_SOFTDIRTY)
1059 			pme = make_pme(0, PM_SOFT_DIRTY);
1060 		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
1061 			err = add_to_pagemap(addr, &pme, pm);
1062 			if (err)
1063 				goto out;
1064 		}
1065 	}
1066 out:
1067 	return err;
1068 }
1069 
1070 static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
1071 		struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1072 {
1073 	u64 frame = 0, flags = 0;
1074 	struct page *page = NULL;
1075 
1076 	if (pte_present(pte)) {
1077 		if (pm->show_pfn)
1078 			frame = pte_pfn(pte);
1079 		flags |= PM_PRESENT;
1080 		page = vm_normal_page(vma, addr, pte);
1081 		if (pte_soft_dirty(pte))
1082 			flags |= PM_SOFT_DIRTY;
1083 	} else if (is_swap_pte(pte)) {
1084 		swp_entry_t entry;
1085 		if (pte_swp_soft_dirty(pte))
1086 			flags |= PM_SOFT_DIRTY;
1087 		entry = pte_to_swp_entry(pte);
1088 		frame = swp_type(entry) |
1089 			(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
1090 		flags |= PM_SWAP;
1091 		if (is_migration_entry(entry))
1092 			page = migration_entry_to_page(entry);
1093 	}
1094 
1095 	if (page && !PageAnon(page))
1096 		flags |= PM_FILE;
1097 	if (page && page_mapcount(page) == 1)
1098 		flags |= PM_MMAP_EXCLUSIVE;
1099 	if (vma->vm_flags & VM_SOFTDIRTY)
1100 		flags |= PM_SOFT_DIRTY;
1101 
1102 	return make_pme(frame, flags);
1103 }
1104 
1105 static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
1106 			     struct mm_walk *walk)
1107 {
1108 	struct vm_area_struct *vma = walk->vma;
1109 	struct pagemapread *pm = walk->private;
1110 	spinlock_t *ptl;
1111 	pte_t *pte, *orig_pte;
1112 	int err = 0;
1113 
1114 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1115 	if (pmd_trans_huge_lock(pmdp, vma, &ptl) == 1) {
1116 		u64 flags = 0, frame = 0;
1117 		pmd_t pmd = *pmdp;
1118 
1119 		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd))
1120 			flags |= PM_SOFT_DIRTY;
1121 
1122 		/*
1123 		 * Currently pmd for thp is always present because thp
1124 		 * can not be swapped-out, migrated, or HWPOISONed
1125 		 * (split in such cases instead.)
1126 		 * This if-check is just to prepare for future implementation.
1127 		 */
1128 		if (pmd_present(pmd)) {
1129 			struct page *page = pmd_page(pmd);
1130 
1131 			if (page_mapcount(page) == 1)
1132 				flags |= PM_MMAP_EXCLUSIVE;
1133 
1134 			flags |= PM_PRESENT;
1135 			if (pm->show_pfn)
1136 				frame = pmd_pfn(pmd) +
1137 					((addr & ~PMD_MASK) >> PAGE_SHIFT);
1138 		}
1139 
1140 		for (; addr != end; addr += PAGE_SIZE) {
1141 			pagemap_entry_t pme = make_pme(frame, flags);
1142 
1143 			err = add_to_pagemap(addr, &pme, pm);
1144 			if (err)
1145 				break;
1146 			if (pm->show_pfn && (flags & PM_PRESENT))
1147 				frame++;
1148 		}
1149 		spin_unlock(ptl);
1150 		return err;
1151 	}
1152 
1153 	if (pmd_trans_unstable(pmdp))
1154 		return 0;
1155 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1156 
1157 	/*
1158 	 * We can assume that @vma always points to a valid one and @end never
1159 	 * goes beyond vma->vm_end.
1160 	 */
1161 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
1162 	for (; addr < end; pte++, addr += PAGE_SIZE) {
1163 		pagemap_entry_t pme;
1164 
1165 		pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
1166 		err = add_to_pagemap(addr, &pme, pm);
1167 		if (err)
1168 			break;
1169 	}
1170 	pte_unmap_unlock(orig_pte, ptl);
1171 
1172 	cond_resched();
1173 
1174 	return err;
1175 }
1176 
1177 #ifdef CONFIG_HUGETLB_PAGE
1178 /* This function walks within one hugetlb entry in the single call */
1179 static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
1180 				 unsigned long addr, unsigned long end,
1181 				 struct mm_walk *walk)
1182 {
1183 	struct pagemapread *pm = walk->private;
1184 	struct vm_area_struct *vma = walk->vma;
1185 	u64 flags = 0, frame = 0;
1186 	int err = 0;
1187 	pte_t pte;
1188 
1189 	if (vma->vm_flags & VM_SOFTDIRTY)
1190 		flags |= PM_SOFT_DIRTY;
1191 
1192 	pte = huge_ptep_get(ptep);
1193 	if (pte_present(pte)) {
1194 		struct page *page = pte_page(pte);
1195 
1196 		if (!PageAnon(page))
1197 			flags |= PM_FILE;
1198 
1199 		if (page_mapcount(page) == 1)
1200 			flags |= PM_MMAP_EXCLUSIVE;
1201 
1202 		flags |= PM_PRESENT;
1203 		if (pm->show_pfn)
1204 			frame = pte_pfn(pte) +
1205 				((addr & ~hmask) >> PAGE_SHIFT);
1206 	}
1207 
1208 	for (; addr != end; addr += PAGE_SIZE) {
1209 		pagemap_entry_t pme = make_pme(frame, flags);
1210 
1211 		err = add_to_pagemap(addr, &pme, pm);
1212 		if (err)
1213 			return err;
1214 		if (pm->show_pfn && (flags & PM_PRESENT))
1215 			frame++;
1216 	}
1217 
1218 	cond_resched();
1219 
1220 	return err;
1221 }
1222 #endif /* HUGETLB_PAGE */
1223 
1224 /*
1225  * /proc/pid/pagemap - an array mapping virtual pages to pfns
1226  *
1227  * For each page in the address space, this file contains one 64-bit entry
1228  * consisting of the following:
1229  *
1230  * Bits 0-54  page frame number (PFN) if present
1231  * Bits 0-4   swap type if swapped
1232  * Bits 5-54  swap offset if swapped
1233  * Bit  55    pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
1234  * Bit  56    page exclusively mapped
1235  * Bits 57-60 zero
1236  * Bit  61    page is file-page or shared-anon
1237  * Bit  62    page swapped
1238  * Bit  63    page present
1239  *
1240  * If the page is not present but in swap, then the PFN contains an
1241  * encoding of the swap file number and the page's offset into the
1242  * swap. Unmapped pages return a null PFN. This allows determining
1243  * precisely which pages are mapped (or in swap) and comparing mapped
1244  * pages between processes.
1245  *
1246  * Efficient users of this interface will use /proc/pid/maps to
1247  * determine which areas of memory are actually mapped and llseek to
1248  * skip over unmapped regions.
1249  */
1250 static ssize_t pagemap_read(struct file *file, char __user *buf,
1251 			    size_t count, loff_t *ppos)
1252 {
1253 	struct mm_struct *mm = file->private_data;
1254 	struct pagemapread pm;
1255 	struct mm_walk pagemap_walk = {};
1256 	unsigned long src;
1257 	unsigned long svpfn;
1258 	unsigned long start_vaddr;
1259 	unsigned long end_vaddr;
1260 	int ret = 0, copied = 0;
1261 
1262 	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
1263 		goto out;
1264 
1265 	ret = -EINVAL;
1266 	/* file position must be aligned */
1267 	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
1268 		goto out_mm;
1269 
1270 	ret = 0;
1271 	if (!count)
1272 		goto out_mm;
1273 
1274 	/* do not disclose physical addresses: attack vector */
1275 	pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
1276 
1277 	pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
1278 	pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
1279 	ret = -ENOMEM;
1280 	if (!pm.buffer)
1281 		goto out_mm;
1282 
1283 	pagemap_walk.pmd_entry = pagemap_pmd_range;
1284 	pagemap_walk.pte_hole = pagemap_pte_hole;
1285 #ifdef CONFIG_HUGETLB_PAGE
1286 	pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
1287 #endif
1288 	pagemap_walk.mm = mm;
1289 	pagemap_walk.private = &pm;
1290 
1291 	src = *ppos;
1292 	svpfn = src / PM_ENTRY_BYTES;
1293 	start_vaddr = svpfn << PAGE_SHIFT;
1294 	end_vaddr = mm->task_size;
1295 
1296 	/* watch out for wraparound */
1297 	if (svpfn > mm->task_size >> PAGE_SHIFT)
1298 		start_vaddr = end_vaddr;
1299 
1300 	/*
1301 	 * The odds are that this will stop walking way
1302 	 * before end_vaddr, because the length of the
1303 	 * user buffer is tracked in "pm", and the walk
1304 	 * will stop when we hit the end of the buffer.
1305 	 */
1306 	ret = 0;
1307 	while (count && (start_vaddr < end_vaddr)) {
1308 		int len;
1309 		unsigned long end;
1310 
1311 		pm.pos = 0;
1312 		end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
1313 		/* overflow ? */
1314 		if (end < start_vaddr || end > end_vaddr)
1315 			end = end_vaddr;
1316 		down_read(&mm->mmap_sem);
1317 		ret = walk_page_range(start_vaddr, end, &pagemap_walk);
1318 		up_read(&mm->mmap_sem);
1319 		start_vaddr = end;
1320 
1321 		len = min(count, PM_ENTRY_BYTES * pm.pos);
1322 		if (copy_to_user(buf, pm.buffer, len)) {
1323 			ret = -EFAULT;
1324 			goto out_free;
1325 		}
1326 		copied += len;
1327 		buf += len;
1328 		count -= len;
1329 	}
1330 	*ppos += copied;
1331 	if (!ret || ret == PM_END_OF_BUFFER)
1332 		ret = copied;
1333 
1334 out_free:
1335 	kfree(pm.buffer);
1336 out_mm:
1337 	mmput(mm);
1338 out:
1339 	return ret;
1340 }
1341 
1342 static int pagemap_open(struct inode *inode, struct file *file)
1343 {
1344 	struct mm_struct *mm;
1345 
1346 	mm = proc_mem_open(inode, PTRACE_MODE_READ);
1347 	if (IS_ERR(mm))
1348 		return PTR_ERR(mm);
1349 	file->private_data = mm;
1350 	return 0;
1351 }
1352 
1353 static int pagemap_release(struct inode *inode, struct file *file)
1354 {
1355 	struct mm_struct *mm = file->private_data;
1356 
1357 	if (mm)
1358 		mmdrop(mm);
1359 	return 0;
1360 }
1361 
1362 const struct file_operations proc_pagemap_operations = {
1363 	.llseek		= mem_lseek, /* borrow this */
1364 	.read		= pagemap_read,
1365 	.open		= pagemap_open,
1366 	.release	= pagemap_release,
1367 };
1368 #endif /* CONFIG_PROC_PAGE_MONITOR */
1369 
1370 #ifdef CONFIG_NUMA
1371 
1372 struct numa_maps {
1373 	unsigned long pages;
1374 	unsigned long anon;
1375 	unsigned long active;
1376 	unsigned long writeback;
1377 	unsigned long mapcount_max;
1378 	unsigned long dirty;
1379 	unsigned long swapcache;
1380 	unsigned long node[MAX_NUMNODES];
1381 };
1382 
1383 struct numa_maps_private {
1384 	struct proc_maps_private proc_maps;
1385 	struct numa_maps md;
1386 };
1387 
1388 static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
1389 			unsigned long nr_pages)
1390 {
1391 	int count = page_mapcount(page);
1392 
1393 	md->pages += nr_pages;
1394 	if (pte_dirty || PageDirty(page))
1395 		md->dirty += nr_pages;
1396 
1397 	if (PageSwapCache(page))
1398 		md->swapcache += nr_pages;
1399 
1400 	if (PageActive(page) || PageUnevictable(page))
1401 		md->active += nr_pages;
1402 
1403 	if (PageWriteback(page))
1404 		md->writeback += nr_pages;
1405 
1406 	if (PageAnon(page))
1407 		md->anon += nr_pages;
1408 
1409 	if (count > md->mapcount_max)
1410 		md->mapcount_max = count;
1411 
1412 	md->node[page_to_nid(page)] += nr_pages;
1413 }
1414 
1415 static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
1416 		unsigned long addr)
1417 {
1418 	struct page *page;
1419 	int nid;
1420 
1421 	if (!pte_present(pte))
1422 		return NULL;
1423 
1424 	page = vm_normal_page(vma, addr, pte);
1425 	if (!page)
1426 		return NULL;
1427 
1428 	if (PageReserved(page))
1429 		return NULL;
1430 
1431 	nid = page_to_nid(page);
1432 	if (!node_isset(nid, node_states[N_MEMORY]))
1433 		return NULL;
1434 
1435 	return page;
1436 }
1437 
1438 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
1439 		unsigned long end, struct mm_walk *walk)
1440 {
1441 	struct numa_maps *md = walk->private;
1442 	struct vm_area_struct *vma = walk->vma;
1443 	spinlock_t *ptl;
1444 	pte_t *orig_pte;
1445 	pte_t *pte;
1446 
1447 	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
1448 		pte_t huge_pte = *(pte_t *)pmd;
1449 		struct page *page;
1450 
1451 		page = can_gather_numa_stats(huge_pte, vma, addr);
1452 		if (page)
1453 			gather_stats(page, md, pte_dirty(huge_pte),
1454 				     HPAGE_PMD_SIZE/PAGE_SIZE);
1455 		spin_unlock(ptl);
1456 		return 0;
1457 	}
1458 
1459 	if (pmd_trans_unstable(pmd))
1460 		return 0;
1461 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
1462 	do {
1463 		struct page *page = can_gather_numa_stats(*pte, vma, addr);
1464 		if (!page)
1465 			continue;
1466 		gather_stats(page, md, pte_dirty(*pte), 1);
1467 
1468 	} while (pte++, addr += PAGE_SIZE, addr != end);
1469 	pte_unmap_unlock(orig_pte, ptl);
1470 	return 0;
1471 }
1472 #ifdef CONFIG_HUGETLB_PAGE
1473 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1474 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1475 {
1476 	struct numa_maps *md;
1477 	struct page *page;
1478 
1479 	if (!pte_present(*pte))
1480 		return 0;
1481 
1482 	page = pte_page(*pte);
1483 	if (!page)
1484 		return 0;
1485 
1486 	md = walk->private;
1487 	gather_stats(page, md, pte_dirty(*pte), 1);
1488 	return 0;
1489 }
1490 
1491 #else
1492 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1493 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1494 {
1495 	return 0;
1496 }
1497 #endif
1498 
1499 /*
1500  * Display pages allocated per node and memory policy via /proc.
1501  */
1502 static int show_numa_map(struct seq_file *m, void *v, int is_pid)
1503 {
1504 	struct numa_maps_private *numa_priv = m->private;
1505 	struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
1506 	struct vm_area_struct *vma = v;
1507 	struct numa_maps *md = &numa_priv->md;
1508 	struct file *file = vma->vm_file;
1509 	struct mm_struct *mm = vma->vm_mm;
1510 	struct mm_walk walk = {
1511 		.hugetlb_entry = gather_hugetlb_stats,
1512 		.pmd_entry = gather_pte_stats,
1513 		.private = md,
1514 		.mm = mm,
1515 	};
1516 	struct mempolicy *pol;
1517 	char buffer[64];
1518 	int nid;
1519 
1520 	if (!mm)
1521 		return 0;
1522 
1523 	/* Ensure we start with an empty set of numa_maps statistics. */
1524 	memset(md, 0, sizeof(*md));
1525 
1526 	pol = __get_vma_policy(vma, vma->vm_start);
1527 	if (pol) {
1528 		mpol_to_str(buffer, sizeof(buffer), pol);
1529 		mpol_cond_put(pol);
1530 	} else {
1531 		mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
1532 	}
1533 
1534 	seq_printf(m, "%08lx %s", vma->vm_start, buffer);
1535 
1536 	if (file) {
1537 		seq_puts(m, " file=");
1538 		seq_file_path(m, file, "\n\t= ");
1539 	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
1540 		seq_puts(m, " heap");
1541 	} else {
1542 		pid_t tid = pid_of_stack(proc_priv, vma, is_pid);
1543 		if (tid != 0) {
1544 			/*
1545 			 * Thread stack in /proc/PID/task/TID/maps or
1546 			 * the main process stack.
1547 			 */
1548 			if (!is_pid || (vma->vm_start <= mm->start_stack &&
1549 			    vma->vm_end >= mm->start_stack))
1550 				seq_puts(m, " stack");
1551 			else
1552 				seq_printf(m, " stack:%d", tid);
1553 		}
1554 	}
1555 
1556 	if (is_vm_hugetlb_page(vma))
1557 		seq_puts(m, " huge");
1558 
1559 	/* mmap_sem is held by m_start */
1560 	walk_page_vma(vma, &walk);
1561 
1562 	if (!md->pages)
1563 		goto out;
1564 
1565 	if (md->anon)
1566 		seq_printf(m, " anon=%lu", md->anon);
1567 
1568 	if (md->dirty)
1569 		seq_printf(m, " dirty=%lu", md->dirty);
1570 
1571 	if (md->pages != md->anon && md->pages != md->dirty)
1572 		seq_printf(m, " mapped=%lu", md->pages);
1573 
1574 	if (md->mapcount_max > 1)
1575 		seq_printf(m, " mapmax=%lu", md->mapcount_max);
1576 
1577 	if (md->swapcache)
1578 		seq_printf(m, " swapcache=%lu", md->swapcache);
1579 
1580 	if (md->active < md->pages && !is_vm_hugetlb_page(vma))
1581 		seq_printf(m, " active=%lu", md->active);
1582 
1583 	if (md->writeback)
1584 		seq_printf(m, " writeback=%lu", md->writeback);
1585 
1586 	for_each_node_state(nid, N_MEMORY)
1587 		if (md->node[nid])
1588 			seq_printf(m, " N%d=%lu", nid, md->node[nid]);
1589 
1590 	seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
1591 out:
1592 	seq_putc(m, '\n');
1593 	m_cache_vma(m, vma);
1594 	return 0;
1595 }
1596 
1597 static int show_pid_numa_map(struct seq_file *m, void *v)
1598 {
1599 	return show_numa_map(m, v, 1);
1600 }
1601 
1602 static int show_tid_numa_map(struct seq_file *m, void *v)
1603 {
1604 	return show_numa_map(m, v, 0);
1605 }
1606 
1607 static const struct seq_operations proc_pid_numa_maps_op = {
1608 	.start  = m_start,
1609 	.next   = m_next,
1610 	.stop   = m_stop,
1611 	.show   = show_pid_numa_map,
1612 };
1613 
1614 static const struct seq_operations proc_tid_numa_maps_op = {
1615 	.start  = m_start,
1616 	.next   = m_next,
1617 	.stop   = m_stop,
1618 	.show   = show_tid_numa_map,
1619 };
1620 
1621 static int numa_maps_open(struct inode *inode, struct file *file,
1622 			  const struct seq_operations *ops)
1623 {
1624 	return proc_maps_open(inode, file, ops,
1625 				sizeof(struct numa_maps_private));
1626 }
1627 
1628 static int pid_numa_maps_open(struct inode *inode, struct file *file)
1629 {
1630 	return numa_maps_open(inode, file, &proc_pid_numa_maps_op);
1631 }
1632 
1633 static int tid_numa_maps_open(struct inode *inode, struct file *file)
1634 {
1635 	return numa_maps_open(inode, file, &proc_tid_numa_maps_op);
1636 }
1637 
1638 const struct file_operations proc_pid_numa_maps_operations = {
1639 	.open		= pid_numa_maps_open,
1640 	.read		= seq_read,
1641 	.llseek		= seq_lseek,
1642 	.release	= proc_map_release,
1643 };
1644 
1645 const struct file_operations proc_tid_numa_maps_operations = {
1646 	.open		= tid_numa_maps_open,
1647 	.read		= seq_read,
1648 	.llseek		= seq_lseek,
1649 	.release	= proc_map_release,
1650 };
1651 #endif /* CONFIG_NUMA */
1652