xref: /openbmc/linux/fs/proc/task_mmu.c (revision 2596e07a)
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 #include <linux/shmem_fs.h>
18 
19 #include <asm/elf.h>
20 #include <asm/uaccess.h>
21 #include <asm/tlbflush.h>
22 #include "internal.h"
23 
24 void task_mem(struct seq_file *m, struct mm_struct *mm)
25 {
26 	unsigned long text, lib, swap, ptes, pmds, anon, file, shmem;
27 	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
28 
29 	anon = get_mm_counter(mm, MM_ANONPAGES);
30 	file = get_mm_counter(mm, MM_FILEPAGES);
31 	shmem = get_mm_counter(mm, MM_SHMEMPAGES);
32 
33 	/*
34 	 * Note: to minimize their overhead, mm maintains hiwater_vm and
35 	 * hiwater_rss only when about to *lower* total_vm or rss.  Any
36 	 * collector of these hiwater stats must therefore get total_vm
37 	 * and rss too, which will usually be the higher.  Barriers? not
38 	 * worth the effort, such snapshots can always be inconsistent.
39 	 */
40 	hiwater_vm = total_vm = mm->total_vm;
41 	if (hiwater_vm < mm->hiwater_vm)
42 		hiwater_vm = mm->hiwater_vm;
43 	hiwater_rss = total_rss = anon + file + shmem;
44 	if (hiwater_rss < mm->hiwater_rss)
45 		hiwater_rss = mm->hiwater_rss;
46 
47 	text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
48 	lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
49 	swap = get_mm_counter(mm, MM_SWAPENTS);
50 	ptes = PTRS_PER_PTE * sizeof(pte_t) * atomic_long_read(&mm->nr_ptes);
51 	pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm);
52 	seq_printf(m,
53 		"VmPeak:\t%8lu kB\n"
54 		"VmSize:\t%8lu kB\n"
55 		"VmLck:\t%8lu kB\n"
56 		"VmPin:\t%8lu kB\n"
57 		"VmHWM:\t%8lu kB\n"
58 		"VmRSS:\t%8lu kB\n"
59 		"RssAnon:\t%8lu kB\n"
60 		"RssFile:\t%8lu kB\n"
61 		"RssShmem:\t%8lu kB\n"
62 		"VmData:\t%8lu kB\n"
63 		"VmStk:\t%8lu kB\n"
64 		"VmExe:\t%8lu kB\n"
65 		"VmLib:\t%8lu kB\n"
66 		"VmPTE:\t%8lu kB\n"
67 		"VmPMD:\t%8lu kB\n"
68 		"VmSwap:\t%8lu kB\n",
69 		hiwater_vm << (PAGE_SHIFT-10),
70 		total_vm << (PAGE_SHIFT-10),
71 		mm->locked_vm << (PAGE_SHIFT-10),
72 		mm->pinned_vm << (PAGE_SHIFT-10),
73 		hiwater_rss << (PAGE_SHIFT-10),
74 		total_rss << (PAGE_SHIFT-10),
75 		anon << (PAGE_SHIFT-10),
76 		file << (PAGE_SHIFT-10),
77 		shmem << (PAGE_SHIFT-10),
78 		mm->data_vm << (PAGE_SHIFT-10),
79 		mm->stack_vm << (PAGE_SHIFT-10), text, lib,
80 		ptes >> 10,
81 		pmds >> 10,
82 		swap << (PAGE_SHIFT-10));
83 	hugetlb_report_usage(m, mm);
84 }
85 
86 unsigned long task_vsize(struct mm_struct *mm)
87 {
88 	return PAGE_SIZE * mm->total_vm;
89 }
90 
91 unsigned long task_statm(struct mm_struct *mm,
92 			 unsigned long *shared, unsigned long *text,
93 			 unsigned long *data, unsigned long *resident)
94 {
95 	*shared = get_mm_counter(mm, MM_FILEPAGES) +
96 			get_mm_counter(mm, MM_SHMEMPAGES);
97 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
98 								>> PAGE_SHIFT;
99 	*data = mm->data_vm + mm->stack_vm;
100 	*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
101 	return mm->total_vm;
102 }
103 
104 #ifdef CONFIG_NUMA
105 /*
106  * Save get_task_policy() for show_numa_map().
107  */
108 static void hold_task_mempolicy(struct proc_maps_private *priv)
109 {
110 	struct task_struct *task = priv->task;
111 
112 	task_lock(task);
113 	priv->task_mempolicy = get_task_policy(task);
114 	mpol_get(priv->task_mempolicy);
115 	task_unlock(task);
116 }
117 static void release_task_mempolicy(struct proc_maps_private *priv)
118 {
119 	mpol_put(priv->task_mempolicy);
120 }
121 #else
122 static void hold_task_mempolicy(struct proc_maps_private *priv)
123 {
124 }
125 static void release_task_mempolicy(struct proc_maps_private *priv)
126 {
127 }
128 #endif
129 
130 static void vma_stop(struct proc_maps_private *priv)
131 {
132 	struct mm_struct *mm = priv->mm;
133 
134 	release_task_mempolicy(priv);
135 	up_read(&mm->mmap_sem);
136 	mmput(mm);
137 }
138 
139 static struct vm_area_struct *
140 m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
141 {
142 	if (vma == priv->tail_vma)
143 		return NULL;
144 	return vma->vm_next ?: priv->tail_vma;
145 }
146 
147 static void m_cache_vma(struct seq_file *m, struct vm_area_struct *vma)
148 {
149 	if (m->count < m->size)	/* vma is copied successfully */
150 		m->version = m_next_vma(m->private, vma) ? vma->vm_start : -1UL;
151 }
152 
153 static void *m_start(struct seq_file *m, loff_t *ppos)
154 {
155 	struct proc_maps_private *priv = m->private;
156 	unsigned long last_addr = m->version;
157 	struct mm_struct *mm;
158 	struct vm_area_struct *vma;
159 	unsigned int pos = *ppos;
160 
161 	/* See m_cache_vma(). Zero at the start or after lseek. */
162 	if (last_addr == -1UL)
163 		return NULL;
164 
165 	priv->task = get_proc_task(priv->inode);
166 	if (!priv->task)
167 		return ERR_PTR(-ESRCH);
168 
169 	mm = priv->mm;
170 	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
171 		return NULL;
172 
173 	down_read(&mm->mmap_sem);
174 	hold_task_mempolicy(priv);
175 	priv->tail_vma = get_gate_vma(mm);
176 
177 	if (last_addr) {
178 		vma = find_vma(mm, last_addr);
179 		if (vma && (vma = m_next_vma(priv, vma)))
180 			return vma;
181 	}
182 
183 	m->version = 0;
184 	if (pos < mm->map_count) {
185 		for (vma = mm->mmap; pos; pos--) {
186 			m->version = vma->vm_start;
187 			vma = vma->vm_next;
188 		}
189 		return vma;
190 	}
191 
192 	/* we do not bother to update m->version in this case */
193 	if (pos == mm->map_count && priv->tail_vma)
194 		return priv->tail_vma;
195 
196 	vma_stop(priv);
197 	return NULL;
198 }
199 
200 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
201 {
202 	struct proc_maps_private *priv = m->private;
203 	struct vm_area_struct *next;
204 
205 	(*pos)++;
206 	next = m_next_vma(priv, v);
207 	if (!next)
208 		vma_stop(priv);
209 	return next;
210 }
211 
212 static void m_stop(struct seq_file *m, void *v)
213 {
214 	struct proc_maps_private *priv = m->private;
215 
216 	if (!IS_ERR_OR_NULL(v))
217 		vma_stop(priv);
218 	if (priv->task) {
219 		put_task_struct(priv->task);
220 		priv->task = NULL;
221 	}
222 }
223 
224 static int proc_maps_open(struct inode *inode, struct file *file,
225 			const struct seq_operations *ops, int psize)
226 {
227 	struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
228 
229 	if (!priv)
230 		return -ENOMEM;
231 
232 	priv->inode = inode;
233 	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
234 	if (IS_ERR(priv->mm)) {
235 		int err = PTR_ERR(priv->mm);
236 
237 		seq_release_private(inode, file);
238 		return err;
239 	}
240 
241 	return 0;
242 }
243 
244 static int proc_map_release(struct inode *inode, struct file *file)
245 {
246 	struct seq_file *seq = file->private_data;
247 	struct proc_maps_private *priv = seq->private;
248 
249 	if (priv->mm)
250 		mmdrop(priv->mm);
251 
252 	return seq_release_private(inode, file);
253 }
254 
255 static int do_maps_open(struct inode *inode, struct file *file,
256 			const struct seq_operations *ops)
257 {
258 	return proc_maps_open(inode, file, ops,
259 				sizeof(struct proc_maps_private));
260 }
261 
262 /*
263  * Indicate if the VMA is a stack for the given task; for
264  * /proc/PID/maps that is the stack of the main task.
265  */
266 static int is_stack(struct proc_maps_private *priv,
267 		    struct vm_area_struct *vma, int is_pid)
268 {
269 	int stack = 0;
270 
271 	if (is_pid) {
272 		stack = vma->vm_start <= vma->vm_mm->start_stack &&
273 			vma->vm_end >= vma->vm_mm->start_stack;
274 	} else {
275 		struct inode *inode = priv->inode;
276 		struct task_struct *task;
277 
278 		rcu_read_lock();
279 		task = pid_task(proc_pid(inode), PIDTYPE_PID);
280 		if (task)
281 			stack = vma_is_stack_for_task(vma, task);
282 		rcu_read_unlock();
283 	}
284 	return stack;
285 }
286 
287 static void
288 show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
289 {
290 	struct mm_struct *mm = vma->vm_mm;
291 	struct file *file = vma->vm_file;
292 	struct proc_maps_private *priv = m->private;
293 	vm_flags_t flags = vma->vm_flags;
294 	unsigned long ino = 0;
295 	unsigned long long pgoff = 0;
296 	unsigned long start, end;
297 	dev_t dev = 0;
298 	const char *name = NULL;
299 
300 	if (file) {
301 		struct inode *inode = file_inode(vma->vm_file);
302 		dev = inode->i_sb->s_dev;
303 		ino = inode->i_ino;
304 		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
305 	}
306 
307 	/* We don't show the stack guard page in /proc/maps */
308 	start = vma->vm_start;
309 	if (stack_guard_page_start(vma, start))
310 		start += PAGE_SIZE;
311 	end = vma->vm_end;
312 	if (stack_guard_page_end(vma, end))
313 		end -= PAGE_SIZE;
314 
315 	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
316 	seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
317 			start,
318 			end,
319 			flags & VM_READ ? 'r' : '-',
320 			flags & VM_WRITE ? 'w' : '-',
321 			flags & VM_EXEC ? 'x' : '-',
322 			flags & VM_MAYSHARE ? 's' : 'p',
323 			pgoff,
324 			MAJOR(dev), MINOR(dev), ino);
325 
326 	/*
327 	 * Print the dentry name for named mappings, and a
328 	 * special [heap] marker for the heap:
329 	 */
330 	if (file) {
331 		seq_pad(m, ' ');
332 		seq_file_path(m, file, "\n");
333 		goto done;
334 	}
335 
336 	if (vma->vm_ops && vma->vm_ops->name) {
337 		name = vma->vm_ops->name(vma);
338 		if (name)
339 			goto done;
340 	}
341 
342 	name = arch_vma_name(vma);
343 	if (!name) {
344 		if (!mm) {
345 			name = "[vdso]";
346 			goto done;
347 		}
348 
349 		if (vma->vm_start <= mm->brk &&
350 		    vma->vm_end >= mm->start_brk) {
351 			name = "[heap]";
352 			goto done;
353 		}
354 
355 		if (is_stack(priv, vma, is_pid))
356 			name = "[stack]";
357 	}
358 
359 done:
360 	if (name) {
361 		seq_pad(m, ' ');
362 		seq_puts(m, name);
363 	}
364 	seq_putc(m, '\n');
365 }
366 
367 static int show_map(struct seq_file *m, void *v, int is_pid)
368 {
369 	show_map_vma(m, v, is_pid);
370 	m_cache_vma(m, v);
371 	return 0;
372 }
373 
374 static int show_pid_map(struct seq_file *m, void *v)
375 {
376 	return show_map(m, v, 1);
377 }
378 
379 static int show_tid_map(struct seq_file *m, void *v)
380 {
381 	return show_map(m, v, 0);
382 }
383 
384 static const struct seq_operations proc_pid_maps_op = {
385 	.start	= m_start,
386 	.next	= m_next,
387 	.stop	= m_stop,
388 	.show	= show_pid_map
389 };
390 
391 static const struct seq_operations proc_tid_maps_op = {
392 	.start	= m_start,
393 	.next	= m_next,
394 	.stop	= m_stop,
395 	.show	= show_tid_map
396 };
397 
398 static int pid_maps_open(struct inode *inode, struct file *file)
399 {
400 	return do_maps_open(inode, file, &proc_pid_maps_op);
401 }
402 
403 static int tid_maps_open(struct inode *inode, struct file *file)
404 {
405 	return do_maps_open(inode, file, &proc_tid_maps_op);
406 }
407 
408 const struct file_operations proc_pid_maps_operations = {
409 	.open		= pid_maps_open,
410 	.read		= seq_read,
411 	.llseek		= seq_lseek,
412 	.release	= proc_map_release,
413 };
414 
415 const struct file_operations proc_tid_maps_operations = {
416 	.open		= tid_maps_open,
417 	.read		= seq_read,
418 	.llseek		= seq_lseek,
419 	.release	= proc_map_release,
420 };
421 
422 /*
423  * Proportional Set Size(PSS): my share of RSS.
424  *
425  * PSS of a process is the count of pages it has in memory, where each
426  * page is divided by the number of processes sharing it.  So if a
427  * process has 1000 pages all to itself, and 1000 shared with one other
428  * process, its PSS will be 1500.
429  *
430  * To keep (accumulated) division errors low, we adopt a 64bit
431  * fixed-point pss counter to minimize division errors. So (pss >>
432  * PSS_SHIFT) would be the real byte count.
433  *
434  * A shift of 12 before division means (assuming 4K page size):
435  * 	- 1M 3-user-pages add up to 8KB errors;
436  * 	- supports mapcount up to 2^24, or 16M;
437  * 	- supports PSS up to 2^52 bytes, or 4PB.
438  */
439 #define PSS_SHIFT 12
440 
441 #ifdef CONFIG_PROC_PAGE_MONITOR
442 struct mem_size_stats {
443 	unsigned long resident;
444 	unsigned long shared_clean;
445 	unsigned long shared_dirty;
446 	unsigned long private_clean;
447 	unsigned long private_dirty;
448 	unsigned long referenced;
449 	unsigned long anonymous;
450 	unsigned long anonymous_thp;
451 	unsigned long swap;
452 	unsigned long shared_hugetlb;
453 	unsigned long private_hugetlb;
454 	u64 pss;
455 	u64 swap_pss;
456 	bool check_shmem_swap;
457 };
458 
459 static void smaps_account(struct mem_size_stats *mss, struct page *page,
460 		bool compound, bool young, bool dirty)
461 {
462 	int i, nr = compound ? 1 << compound_order(page) : 1;
463 	unsigned long size = nr * PAGE_SIZE;
464 
465 	if (PageAnon(page))
466 		mss->anonymous += size;
467 
468 	mss->resident += size;
469 	/* Accumulate the size in pages that have been accessed. */
470 	if (young || page_is_young(page) || PageReferenced(page))
471 		mss->referenced += size;
472 
473 	/*
474 	 * page_count(page) == 1 guarantees the page is mapped exactly once.
475 	 * If any subpage of the compound page mapped with PTE it would elevate
476 	 * page_count().
477 	 */
478 	if (page_count(page) == 1) {
479 		if (dirty || PageDirty(page))
480 			mss->private_dirty += size;
481 		else
482 			mss->private_clean += size;
483 		mss->pss += (u64)size << PSS_SHIFT;
484 		return;
485 	}
486 
487 	for (i = 0; i < nr; i++, page++) {
488 		int mapcount = page_mapcount(page);
489 
490 		if (mapcount >= 2) {
491 			if (dirty || PageDirty(page))
492 				mss->shared_dirty += PAGE_SIZE;
493 			else
494 				mss->shared_clean += PAGE_SIZE;
495 			mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
496 		} else {
497 			if (dirty || PageDirty(page))
498 				mss->private_dirty += PAGE_SIZE;
499 			else
500 				mss->private_clean += PAGE_SIZE;
501 			mss->pss += PAGE_SIZE << PSS_SHIFT;
502 		}
503 	}
504 }
505 
506 #ifdef CONFIG_SHMEM
507 static int smaps_pte_hole(unsigned long addr, unsigned long end,
508 		struct mm_walk *walk)
509 {
510 	struct mem_size_stats *mss = walk->private;
511 
512 	mss->swap += shmem_partial_swap_usage(
513 			walk->vma->vm_file->f_mapping, addr, end);
514 
515 	return 0;
516 }
517 #endif
518 
519 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
520 		struct mm_walk *walk)
521 {
522 	struct mem_size_stats *mss = walk->private;
523 	struct vm_area_struct *vma = walk->vma;
524 	struct page *page = NULL;
525 
526 	if (pte_present(*pte)) {
527 		page = vm_normal_page(vma, addr, *pte);
528 	} else if (is_swap_pte(*pte)) {
529 		swp_entry_t swpent = pte_to_swp_entry(*pte);
530 
531 		if (!non_swap_entry(swpent)) {
532 			int mapcount;
533 
534 			mss->swap += PAGE_SIZE;
535 			mapcount = swp_swapcount(swpent);
536 			if (mapcount >= 2) {
537 				u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
538 
539 				do_div(pss_delta, mapcount);
540 				mss->swap_pss += pss_delta;
541 			} else {
542 				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
543 			}
544 		} else if (is_migration_entry(swpent))
545 			page = migration_entry_to_page(swpent);
546 	} else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap
547 							&& pte_none(*pte))) {
548 		page = find_get_entry(vma->vm_file->f_mapping,
549 						linear_page_index(vma, addr));
550 		if (!page)
551 			return;
552 
553 		if (radix_tree_exceptional_entry(page))
554 			mss->swap += PAGE_SIZE;
555 		else
556 			page_cache_release(page);
557 
558 		return;
559 	}
560 
561 	if (!page)
562 		return;
563 
564 	smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte));
565 }
566 
567 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
568 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
569 		struct mm_walk *walk)
570 {
571 	struct mem_size_stats *mss = walk->private;
572 	struct vm_area_struct *vma = walk->vma;
573 	struct page *page;
574 
575 	/* FOLL_DUMP will return -EFAULT on huge zero page */
576 	page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
577 	if (IS_ERR_OR_NULL(page))
578 		return;
579 	mss->anonymous_thp += HPAGE_PMD_SIZE;
580 	smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd));
581 }
582 #else
583 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
584 		struct mm_walk *walk)
585 {
586 }
587 #endif
588 
589 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
590 			   struct mm_walk *walk)
591 {
592 	struct vm_area_struct *vma = walk->vma;
593 	pte_t *pte;
594 	spinlock_t *ptl;
595 
596 	ptl = pmd_trans_huge_lock(pmd, vma);
597 	if (ptl) {
598 		smaps_pmd_entry(pmd, addr, walk);
599 		spin_unlock(ptl);
600 		return 0;
601 	}
602 
603 	if (pmd_trans_unstable(pmd))
604 		return 0;
605 	/*
606 	 * The mmap_sem held all the way back in m_start() is what
607 	 * keeps khugepaged out of here and from collapsing things
608 	 * in here.
609 	 */
610 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
611 	for (; addr != end; pte++, addr += PAGE_SIZE)
612 		smaps_pte_entry(pte, addr, walk);
613 	pte_unmap_unlock(pte - 1, ptl);
614 	cond_resched();
615 	return 0;
616 }
617 
618 static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
619 {
620 	/*
621 	 * Don't forget to update Documentation/ on changes.
622 	 */
623 	static const char mnemonics[BITS_PER_LONG][2] = {
624 		/*
625 		 * In case if we meet a flag we don't know about.
626 		 */
627 		[0 ... (BITS_PER_LONG-1)] = "??",
628 
629 		[ilog2(VM_READ)]	= "rd",
630 		[ilog2(VM_WRITE)]	= "wr",
631 		[ilog2(VM_EXEC)]	= "ex",
632 		[ilog2(VM_SHARED)]	= "sh",
633 		[ilog2(VM_MAYREAD)]	= "mr",
634 		[ilog2(VM_MAYWRITE)]	= "mw",
635 		[ilog2(VM_MAYEXEC)]	= "me",
636 		[ilog2(VM_MAYSHARE)]	= "ms",
637 		[ilog2(VM_GROWSDOWN)]	= "gd",
638 		[ilog2(VM_PFNMAP)]	= "pf",
639 		[ilog2(VM_DENYWRITE)]	= "dw",
640 #ifdef CONFIG_X86_INTEL_MPX
641 		[ilog2(VM_MPX)]		= "mp",
642 #endif
643 		[ilog2(VM_LOCKED)]	= "lo",
644 		[ilog2(VM_IO)]		= "io",
645 		[ilog2(VM_SEQ_READ)]	= "sr",
646 		[ilog2(VM_RAND_READ)]	= "rr",
647 		[ilog2(VM_DONTCOPY)]	= "dc",
648 		[ilog2(VM_DONTEXPAND)]	= "de",
649 		[ilog2(VM_ACCOUNT)]	= "ac",
650 		[ilog2(VM_NORESERVE)]	= "nr",
651 		[ilog2(VM_HUGETLB)]	= "ht",
652 		[ilog2(VM_ARCH_1)]	= "ar",
653 		[ilog2(VM_DONTDUMP)]	= "dd",
654 #ifdef CONFIG_MEM_SOFT_DIRTY
655 		[ilog2(VM_SOFTDIRTY)]	= "sd",
656 #endif
657 		[ilog2(VM_MIXEDMAP)]	= "mm",
658 		[ilog2(VM_HUGEPAGE)]	= "hg",
659 		[ilog2(VM_NOHUGEPAGE)]	= "nh",
660 		[ilog2(VM_MERGEABLE)]	= "mg",
661 		[ilog2(VM_UFFD_MISSING)]= "um",
662 		[ilog2(VM_UFFD_WP)]	= "uw",
663 	};
664 	size_t i;
665 
666 	seq_puts(m, "VmFlags: ");
667 	for (i = 0; i < BITS_PER_LONG; i++) {
668 		if (vma->vm_flags & (1UL << i)) {
669 			seq_printf(m, "%c%c ",
670 				   mnemonics[i][0], mnemonics[i][1]);
671 		}
672 	}
673 	seq_putc(m, '\n');
674 }
675 
676 #ifdef CONFIG_HUGETLB_PAGE
677 static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
678 				 unsigned long addr, unsigned long end,
679 				 struct mm_walk *walk)
680 {
681 	struct mem_size_stats *mss = walk->private;
682 	struct vm_area_struct *vma = walk->vma;
683 	struct page *page = NULL;
684 
685 	if (pte_present(*pte)) {
686 		page = vm_normal_page(vma, addr, *pte);
687 	} else if (is_swap_pte(*pte)) {
688 		swp_entry_t swpent = pte_to_swp_entry(*pte);
689 
690 		if (is_migration_entry(swpent))
691 			page = migration_entry_to_page(swpent);
692 	}
693 	if (page) {
694 		int mapcount = page_mapcount(page);
695 
696 		if (mapcount >= 2)
697 			mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
698 		else
699 			mss->private_hugetlb += huge_page_size(hstate_vma(vma));
700 	}
701 	return 0;
702 }
703 #endif /* HUGETLB_PAGE */
704 
705 static int show_smap(struct seq_file *m, void *v, int is_pid)
706 {
707 	struct vm_area_struct *vma = v;
708 	struct mem_size_stats mss;
709 	struct mm_walk smaps_walk = {
710 		.pmd_entry = smaps_pte_range,
711 #ifdef CONFIG_HUGETLB_PAGE
712 		.hugetlb_entry = smaps_hugetlb_range,
713 #endif
714 		.mm = vma->vm_mm,
715 		.private = &mss,
716 	};
717 
718 	memset(&mss, 0, sizeof mss);
719 
720 #ifdef CONFIG_SHMEM
721 	if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
722 		/*
723 		 * For shared or readonly shmem mappings we know that all
724 		 * swapped out pages belong to the shmem object, and we can
725 		 * obtain the swap value much more efficiently. For private
726 		 * writable mappings, we might have COW pages that are
727 		 * not affected by the parent swapped out pages of the shmem
728 		 * object, so we have to distinguish them during the page walk.
729 		 * Unless we know that the shmem object (or the part mapped by
730 		 * our VMA) has no swapped out pages at all.
731 		 */
732 		unsigned long shmem_swapped = shmem_swap_usage(vma);
733 
734 		if (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
735 					!(vma->vm_flags & VM_WRITE)) {
736 			mss.swap = shmem_swapped;
737 		} else {
738 			mss.check_shmem_swap = true;
739 			smaps_walk.pte_hole = smaps_pte_hole;
740 		}
741 	}
742 #endif
743 
744 	/* mmap_sem is held in m_start */
745 	walk_page_vma(vma, &smaps_walk);
746 
747 	show_map_vma(m, vma, is_pid);
748 
749 	seq_printf(m,
750 		   "Size:           %8lu kB\n"
751 		   "Rss:            %8lu kB\n"
752 		   "Pss:            %8lu kB\n"
753 		   "Shared_Clean:   %8lu kB\n"
754 		   "Shared_Dirty:   %8lu kB\n"
755 		   "Private_Clean:  %8lu kB\n"
756 		   "Private_Dirty:  %8lu kB\n"
757 		   "Referenced:     %8lu kB\n"
758 		   "Anonymous:      %8lu kB\n"
759 		   "AnonHugePages:  %8lu kB\n"
760 		   "Shared_Hugetlb: %8lu kB\n"
761 		   "Private_Hugetlb: %7lu kB\n"
762 		   "Swap:           %8lu kB\n"
763 		   "SwapPss:        %8lu kB\n"
764 		   "KernelPageSize: %8lu kB\n"
765 		   "MMUPageSize:    %8lu kB\n"
766 		   "Locked:         %8lu kB\n",
767 		   (vma->vm_end - vma->vm_start) >> 10,
768 		   mss.resident >> 10,
769 		   (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
770 		   mss.shared_clean  >> 10,
771 		   mss.shared_dirty  >> 10,
772 		   mss.private_clean >> 10,
773 		   mss.private_dirty >> 10,
774 		   mss.referenced >> 10,
775 		   mss.anonymous >> 10,
776 		   mss.anonymous_thp >> 10,
777 		   mss.shared_hugetlb >> 10,
778 		   mss.private_hugetlb >> 10,
779 		   mss.swap >> 10,
780 		   (unsigned long)(mss.swap_pss >> (10 + PSS_SHIFT)),
781 		   vma_kernel_pagesize(vma) >> 10,
782 		   vma_mmu_pagesize(vma) >> 10,
783 		   (vma->vm_flags & VM_LOCKED) ?
784 			(unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
785 
786 	show_smap_vma_flags(m, vma);
787 	m_cache_vma(m, vma);
788 	return 0;
789 }
790 
791 static int show_pid_smap(struct seq_file *m, void *v)
792 {
793 	return show_smap(m, v, 1);
794 }
795 
796 static int show_tid_smap(struct seq_file *m, void *v)
797 {
798 	return show_smap(m, v, 0);
799 }
800 
801 static const struct seq_operations proc_pid_smaps_op = {
802 	.start	= m_start,
803 	.next	= m_next,
804 	.stop	= m_stop,
805 	.show	= show_pid_smap
806 };
807 
808 static const struct seq_operations proc_tid_smaps_op = {
809 	.start	= m_start,
810 	.next	= m_next,
811 	.stop	= m_stop,
812 	.show	= show_tid_smap
813 };
814 
815 static int pid_smaps_open(struct inode *inode, struct file *file)
816 {
817 	return do_maps_open(inode, file, &proc_pid_smaps_op);
818 }
819 
820 static int tid_smaps_open(struct inode *inode, struct file *file)
821 {
822 	return do_maps_open(inode, file, &proc_tid_smaps_op);
823 }
824 
825 const struct file_operations proc_pid_smaps_operations = {
826 	.open		= pid_smaps_open,
827 	.read		= seq_read,
828 	.llseek		= seq_lseek,
829 	.release	= proc_map_release,
830 };
831 
832 const struct file_operations proc_tid_smaps_operations = {
833 	.open		= tid_smaps_open,
834 	.read		= seq_read,
835 	.llseek		= seq_lseek,
836 	.release	= proc_map_release,
837 };
838 
839 enum clear_refs_types {
840 	CLEAR_REFS_ALL = 1,
841 	CLEAR_REFS_ANON,
842 	CLEAR_REFS_MAPPED,
843 	CLEAR_REFS_SOFT_DIRTY,
844 	CLEAR_REFS_MM_HIWATER_RSS,
845 	CLEAR_REFS_LAST,
846 };
847 
848 struct clear_refs_private {
849 	enum clear_refs_types type;
850 };
851 
852 #ifdef CONFIG_MEM_SOFT_DIRTY
853 static inline void clear_soft_dirty(struct vm_area_struct *vma,
854 		unsigned long addr, pte_t *pte)
855 {
856 	/*
857 	 * The soft-dirty tracker uses #PF-s to catch writes
858 	 * to pages, so write-protect the pte as well. See the
859 	 * Documentation/vm/soft-dirty.txt for full description
860 	 * of how soft-dirty works.
861 	 */
862 	pte_t ptent = *pte;
863 
864 	if (pte_present(ptent)) {
865 		ptent = ptep_modify_prot_start(vma->vm_mm, addr, pte);
866 		ptent = pte_wrprotect(ptent);
867 		ptent = pte_clear_soft_dirty(ptent);
868 		ptep_modify_prot_commit(vma->vm_mm, addr, pte, ptent);
869 	} else if (is_swap_pte(ptent)) {
870 		ptent = pte_swp_clear_soft_dirty(ptent);
871 		set_pte_at(vma->vm_mm, addr, pte, ptent);
872 	}
873 }
874 #else
875 static inline void clear_soft_dirty(struct vm_area_struct *vma,
876 		unsigned long addr, pte_t *pte)
877 {
878 }
879 #endif
880 
881 #if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
882 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
883 		unsigned long addr, pmd_t *pmdp)
884 {
885 	pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
886 
887 	pmd = pmd_wrprotect(pmd);
888 	pmd = pmd_clear_soft_dirty(pmd);
889 
890 	set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
891 }
892 #else
893 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
894 		unsigned long addr, pmd_t *pmdp)
895 {
896 }
897 #endif
898 
899 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
900 				unsigned long end, struct mm_walk *walk)
901 {
902 	struct clear_refs_private *cp = walk->private;
903 	struct vm_area_struct *vma = walk->vma;
904 	pte_t *pte, ptent;
905 	spinlock_t *ptl;
906 	struct page *page;
907 
908 	ptl = pmd_trans_huge_lock(pmd, vma);
909 	if (ptl) {
910 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
911 			clear_soft_dirty_pmd(vma, addr, pmd);
912 			goto out;
913 		}
914 
915 		page = pmd_page(*pmd);
916 
917 		/* Clear accessed and referenced bits. */
918 		pmdp_test_and_clear_young(vma, addr, pmd);
919 		test_and_clear_page_young(page);
920 		ClearPageReferenced(page);
921 out:
922 		spin_unlock(ptl);
923 		return 0;
924 	}
925 
926 	if (pmd_trans_unstable(pmd))
927 		return 0;
928 
929 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
930 	for (; addr != end; pte++, addr += PAGE_SIZE) {
931 		ptent = *pte;
932 
933 		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
934 			clear_soft_dirty(vma, addr, pte);
935 			continue;
936 		}
937 
938 		if (!pte_present(ptent))
939 			continue;
940 
941 		page = vm_normal_page(vma, addr, ptent);
942 		if (!page)
943 			continue;
944 
945 		/* Clear accessed and referenced bits. */
946 		ptep_test_and_clear_young(vma, addr, pte);
947 		test_and_clear_page_young(page);
948 		ClearPageReferenced(page);
949 	}
950 	pte_unmap_unlock(pte - 1, ptl);
951 	cond_resched();
952 	return 0;
953 }
954 
955 static int clear_refs_test_walk(unsigned long start, unsigned long end,
956 				struct mm_walk *walk)
957 {
958 	struct clear_refs_private *cp = walk->private;
959 	struct vm_area_struct *vma = walk->vma;
960 
961 	if (vma->vm_flags & VM_PFNMAP)
962 		return 1;
963 
964 	/*
965 	 * Writing 1 to /proc/pid/clear_refs affects all pages.
966 	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
967 	 * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
968 	 * Writing 4 to /proc/pid/clear_refs affects all pages.
969 	 */
970 	if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
971 		return 1;
972 	if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
973 		return 1;
974 	return 0;
975 }
976 
977 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
978 				size_t count, loff_t *ppos)
979 {
980 	struct task_struct *task;
981 	char buffer[PROC_NUMBUF];
982 	struct mm_struct *mm;
983 	struct vm_area_struct *vma;
984 	enum clear_refs_types type;
985 	int itype;
986 	int rv;
987 
988 	memset(buffer, 0, sizeof(buffer));
989 	if (count > sizeof(buffer) - 1)
990 		count = sizeof(buffer) - 1;
991 	if (copy_from_user(buffer, buf, count))
992 		return -EFAULT;
993 	rv = kstrtoint(strstrip(buffer), 10, &itype);
994 	if (rv < 0)
995 		return rv;
996 	type = (enum clear_refs_types)itype;
997 	if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
998 		return -EINVAL;
999 
1000 	task = get_proc_task(file_inode(file));
1001 	if (!task)
1002 		return -ESRCH;
1003 	mm = get_task_mm(task);
1004 	if (mm) {
1005 		struct clear_refs_private cp = {
1006 			.type = type,
1007 		};
1008 		struct mm_walk clear_refs_walk = {
1009 			.pmd_entry = clear_refs_pte_range,
1010 			.test_walk = clear_refs_test_walk,
1011 			.mm = mm,
1012 			.private = &cp,
1013 		};
1014 
1015 		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
1016 			/*
1017 			 * Writing 5 to /proc/pid/clear_refs resets the peak
1018 			 * resident set size to this mm's current rss value.
1019 			 */
1020 			down_write(&mm->mmap_sem);
1021 			reset_mm_hiwater_rss(mm);
1022 			up_write(&mm->mmap_sem);
1023 			goto out_mm;
1024 		}
1025 
1026 		down_read(&mm->mmap_sem);
1027 		if (type == CLEAR_REFS_SOFT_DIRTY) {
1028 			for (vma = mm->mmap; vma; vma = vma->vm_next) {
1029 				if (!(vma->vm_flags & VM_SOFTDIRTY))
1030 					continue;
1031 				up_read(&mm->mmap_sem);
1032 				down_write(&mm->mmap_sem);
1033 				for (vma = mm->mmap; vma; vma = vma->vm_next) {
1034 					vma->vm_flags &= ~VM_SOFTDIRTY;
1035 					vma_set_page_prot(vma);
1036 				}
1037 				downgrade_write(&mm->mmap_sem);
1038 				break;
1039 			}
1040 			mmu_notifier_invalidate_range_start(mm, 0, -1);
1041 		}
1042 		walk_page_range(0, ~0UL, &clear_refs_walk);
1043 		if (type == CLEAR_REFS_SOFT_DIRTY)
1044 			mmu_notifier_invalidate_range_end(mm, 0, -1);
1045 		flush_tlb_mm(mm);
1046 		up_read(&mm->mmap_sem);
1047 out_mm:
1048 		mmput(mm);
1049 	}
1050 	put_task_struct(task);
1051 
1052 	return count;
1053 }
1054 
1055 const struct file_operations proc_clear_refs_operations = {
1056 	.write		= clear_refs_write,
1057 	.llseek		= noop_llseek,
1058 };
1059 
1060 typedef struct {
1061 	u64 pme;
1062 } pagemap_entry_t;
1063 
1064 struct pagemapread {
1065 	int pos, len;		/* units: PM_ENTRY_BYTES, not bytes */
1066 	pagemap_entry_t *buffer;
1067 	bool show_pfn;
1068 };
1069 
1070 #define PAGEMAP_WALK_SIZE	(PMD_SIZE)
1071 #define PAGEMAP_WALK_MASK	(PMD_MASK)
1072 
1073 #define PM_ENTRY_BYTES		sizeof(pagemap_entry_t)
1074 #define PM_PFRAME_BITS		55
1075 #define PM_PFRAME_MASK		GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
1076 #define PM_SOFT_DIRTY		BIT_ULL(55)
1077 #define PM_MMAP_EXCLUSIVE	BIT_ULL(56)
1078 #define PM_FILE			BIT_ULL(61)
1079 #define PM_SWAP			BIT_ULL(62)
1080 #define PM_PRESENT		BIT_ULL(63)
1081 
1082 #define PM_END_OF_BUFFER    1
1083 
1084 static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
1085 {
1086 	return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
1087 }
1088 
1089 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
1090 			  struct pagemapread *pm)
1091 {
1092 	pm->buffer[pm->pos++] = *pme;
1093 	if (pm->pos >= pm->len)
1094 		return PM_END_OF_BUFFER;
1095 	return 0;
1096 }
1097 
1098 static int pagemap_pte_hole(unsigned long start, unsigned long end,
1099 				struct mm_walk *walk)
1100 {
1101 	struct pagemapread *pm = walk->private;
1102 	unsigned long addr = start;
1103 	int err = 0;
1104 
1105 	while (addr < end) {
1106 		struct vm_area_struct *vma = find_vma(walk->mm, addr);
1107 		pagemap_entry_t pme = make_pme(0, 0);
1108 		/* End of address space hole, which we mark as non-present. */
1109 		unsigned long hole_end;
1110 
1111 		if (vma)
1112 			hole_end = min(end, vma->vm_start);
1113 		else
1114 			hole_end = end;
1115 
1116 		for (; addr < hole_end; addr += PAGE_SIZE) {
1117 			err = add_to_pagemap(addr, &pme, pm);
1118 			if (err)
1119 				goto out;
1120 		}
1121 
1122 		if (!vma)
1123 			break;
1124 
1125 		/* Addresses in the VMA. */
1126 		if (vma->vm_flags & VM_SOFTDIRTY)
1127 			pme = make_pme(0, PM_SOFT_DIRTY);
1128 		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
1129 			err = add_to_pagemap(addr, &pme, pm);
1130 			if (err)
1131 				goto out;
1132 		}
1133 	}
1134 out:
1135 	return err;
1136 }
1137 
1138 static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
1139 		struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1140 {
1141 	u64 frame = 0, flags = 0;
1142 	struct page *page = NULL;
1143 
1144 	if (pte_present(pte)) {
1145 		if (pm->show_pfn)
1146 			frame = pte_pfn(pte);
1147 		flags |= PM_PRESENT;
1148 		page = vm_normal_page(vma, addr, pte);
1149 		if (pte_soft_dirty(pte))
1150 			flags |= PM_SOFT_DIRTY;
1151 	} else if (is_swap_pte(pte)) {
1152 		swp_entry_t entry;
1153 		if (pte_swp_soft_dirty(pte))
1154 			flags |= PM_SOFT_DIRTY;
1155 		entry = pte_to_swp_entry(pte);
1156 		frame = swp_type(entry) |
1157 			(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
1158 		flags |= PM_SWAP;
1159 		if (is_migration_entry(entry))
1160 			page = migration_entry_to_page(entry);
1161 	}
1162 
1163 	if (page && !PageAnon(page))
1164 		flags |= PM_FILE;
1165 	if (page && page_mapcount(page) == 1)
1166 		flags |= PM_MMAP_EXCLUSIVE;
1167 	if (vma->vm_flags & VM_SOFTDIRTY)
1168 		flags |= PM_SOFT_DIRTY;
1169 
1170 	return make_pme(frame, flags);
1171 }
1172 
1173 static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
1174 			     struct mm_walk *walk)
1175 {
1176 	struct vm_area_struct *vma = walk->vma;
1177 	struct pagemapread *pm = walk->private;
1178 	spinlock_t *ptl;
1179 	pte_t *pte, *orig_pte;
1180 	int err = 0;
1181 
1182 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1183 	ptl = pmd_trans_huge_lock(pmdp, vma);
1184 	if (ptl) {
1185 		u64 flags = 0, frame = 0;
1186 		pmd_t pmd = *pmdp;
1187 
1188 		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd))
1189 			flags |= PM_SOFT_DIRTY;
1190 
1191 		/*
1192 		 * Currently pmd for thp is always present because thp
1193 		 * can not be swapped-out, migrated, or HWPOISONed
1194 		 * (split in such cases instead.)
1195 		 * This if-check is just to prepare for future implementation.
1196 		 */
1197 		if (pmd_present(pmd)) {
1198 			struct page *page = pmd_page(pmd);
1199 
1200 			if (page_mapcount(page) == 1)
1201 				flags |= PM_MMAP_EXCLUSIVE;
1202 
1203 			flags |= PM_PRESENT;
1204 			if (pm->show_pfn)
1205 				frame = pmd_pfn(pmd) +
1206 					((addr & ~PMD_MASK) >> PAGE_SHIFT);
1207 		}
1208 
1209 		for (; addr != end; addr += PAGE_SIZE) {
1210 			pagemap_entry_t pme = make_pme(frame, flags);
1211 
1212 			err = add_to_pagemap(addr, &pme, pm);
1213 			if (err)
1214 				break;
1215 			if (pm->show_pfn && (flags & PM_PRESENT))
1216 				frame++;
1217 		}
1218 		spin_unlock(ptl);
1219 		return err;
1220 	}
1221 
1222 	if (pmd_trans_unstable(pmdp))
1223 		return 0;
1224 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1225 
1226 	/*
1227 	 * We can assume that @vma always points to a valid one and @end never
1228 	 * goes beyond vma->vm_end.
1229 	 */
1230 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
1231 	for (; addr < end; pte++, addr += PAGE_SIZE) {
1232 		pagemap_entry_t pme;
1233 
1234 		pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
1235 		err = add_to_pagemap(addr, &pme, pm);
1236 		if (err)
1237 			break;
1238 	}
1239 	pte_unmap_unlock(orig_pte, ptl);
1240 
1241 	cond_resched();
1242 
1243 	return err;
1244 }
1245 
1246 #ifdef CONFIG_HUGETLB_PAGE
1247 /* This function walks within one hugetlb entry in the single call */
1248 static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
1249 				 unsigned long addr, unsigned long end,
1250 				 struct mm_walk *walk)
1251 {
1252 	struct pagemapread *pm = walk->private;
1253 	struct vm_area_struct *vma = walk->vma;
1254 	u64 flags = 0, frame = 0;
1255 	int err = 0;
1256 	pte_t pte;
1257 
1258 	if (vma->vm_flags & VM_SOFTDIRTY)
1259 		flags |= PM_SOFT_DIRTY;
1260 
1261 	pte = huge_ptep_get(ptep);
1262 	if (pte_present(pte)) {
1263 		struct page *page = pte_page(pte);
1264 
1265 		if (!PageAnon(page))
1266 			flags |= PM_FILE;
1267 
1268 		if (page_mapcount(page) == 1)
1269 			flags |= PM_MMAP_EXCLUSIVE;
1270 
1271 		flags |= PM_PRESENT;
1272 		if (pm->show_pfn)
1273 			frame = pte_pfn(pte) +
1274 				((addr & ~hmask) >> PAGE_SHIFT);
1275 	}
1276 
1277 	for (; addr != end; addr += PAGE_SIZE) {
1278 		pagemap_entry_t pme = make_pme(frame, flags);
1279 
1280 		err = add_to_pagemap(addr, &pme, pm);
1281 		if (err)
1282 			return err;
1283 		if (pm->show_pfn && (flags & PM_PRESENT))
1284 			frame++;
1285 	}
1286 
1287 	cond_resched();
1288 
1289 	return err;
1290 }
1291 #endif /* HUGETLB_PAGE */
1292 
1293 /*
1294  * /proc/pid/pagemap - an array mapping virtual pages to pfns
1295  *
1296  * For each page in the address space, this file contains one 64-bit entry
1297  * consisting of the following:
1298  *
1299  * Bits 0-54  page frame number (PFN) if present
1300  * Bits 0-4   swap type if swapped
1301  * Bits 5-54  swap offset if swapped
1302  * Bit  55    pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
1303  * Bit  56    page exclusively mapped
1304  * Bits 57-60 zero
1305  * Bit  61    page is file-page or shared-anon
1306  * Bit  62    page swapped
1307  * Bit  63    page present
1308  *
1309  * If the page is not present but in swap, then the PFN contains an
1310  * encoding of the swap file number and the page's offset into the
1311  * swap. Unmapped pages return a null PFN. This allows determining
1312  * precisely which pages are mapped (or in swap) and comparing mapped
1313  * pages between processes.
1314  *
1315  * Efficient users of this interface will use /proc/pid/maps to
1316  * determine which areas of memory are actually mapped and llseek to
1317  * skip over unmapped regions.
1318  */
1319 static ssize_t pagemap_read(struct file *file, char __user *buf,
1320 			    size_t count, loff_t *ppos)
1321 {
1322 	struct mm_struct *mm = file->private_data;
1323 	struct pagemapread pm;
1324 	struct mm_walk pagemap_walk = {};
1325 	unsigned long src;
1326 	unsigned long svpfn;
1327 	unsigned long start_vaddr;
1328 	unsigned long end_vaddr;
1329 	int ret = 0, copied = 0;
1330 
1331 	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
1332 		goto out;
1333 
1334 	ret = -EINVAL;
1335 	/* file position must be aligned */
1336 	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
1337 		goto out_mm;
1338 
1339 	ret = 0;
1340 	if (!count)
1341 		goto out_mm;
1342 
1343 	/* do not disclose physical addresses: attack vector */
1344 	pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
1345 
1346 	pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
1347 	pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
1348 	ret = -ENOMEM;
1349 	if (!pm.buffer)
1350 		goto out_mm;
1351 
1352 	pagemap_walk.pmd_entry = pagemap_pmd_range;
1353 	pagemap_walk.pte_hole = pagemap_pte_hole;
1354 #ifdef CONFIG_HUGETLB_PAGE
1355 	pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
1356 #endif
1357 	pagemap_walk.mm = mm;
1358 	pagemap_walk.private = &pm;
1359 
1360 	src = *ppos;
1361 	svpfn = src / PM_ENTRY_BYTES;
1362 	start_vaddr = svpfn << PAGE_SHIFT;
1363 	end_vaddr = mm->task_size;
1364 
1365 	/* watch out for wraparound */
1366 	if (svpfn > mm->task_size >> PAGE_SHIFT)
1367 		start_vaddr = end_vaddr;
1368 
1369 	/*
1370 	 * The odds are that this will stop walking way
1371 	 * before end_vaddr, because the length of the
1372 	 * user buffer is tracked in "pm", and the walk
1373 	 * will stop when we hit the end of the buffer.
1374 	 */
1375 	ret = 0;
1376 	while (count && (start_vaddr < end_vaddr)) {
1377 		int len;
1378 		unsigned long end;
1379 
1380 		pm.pos = 0;
1381 		end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
1382 		/* overflow ? */
1383 		if (end < start_vaddr || end > end_vaddr)
1384 			end = end_vaddr;
1385 		down_read(&mm->mmap_sem);
1386 		ret = walk_page_range(start_vaddr, end, &pagemap_walk);
1387 		up_read(&mm->mmap_sem);
1388 		start_vaddr = end;
1389 
1390 		len = min(count, PM_ENTRY_BYTES * pm.pos);
1391 		if (copy_to_user(buf, pm.buffer, len)) {
1392 			ret = -EFAULT;
1393 			goto out_free;
1394 		}
1395 		copied += len;
1396 		buf += len;
1397 		count -= len;
1398 	}
1399 	*ppos += copied;
1400 	if (!ret || ret == PM_END_OF_BUFFER)
1401 		ret = copied;
1402 
1403 out_free:
1404 	kfree(pm.buffer);
1405 out_mm:
1406 	mmput(mm);
1407 out:
1408 	return ret;
1409 }
1410 
1411 static int pagemap_open(struct inode *inode, struct file *file)
1412 {
1413 	struct mm_struct *mm;
1414 
1415 	mm = proc_mem_open(inode, PTRACE_MODE_READ);
1416 	if (IS_ERR(mm))
1417 		return PTR_ERR(mm);
1418 	file->private_data = mm;
1419 	return 0;
1420 }
1421 
1422 static int pagemap_release(struct inode *inode, struct file *file)
1423 {
1424 	struct mm_struct *mm = file->private_data;
1425 
1426 	if (mm)
1427 		mmdrop(mm);
1428 	return 0;
1429 }
1430 
1431 const struct file_operations proc_pagemap_operations = {
1432 	.llseek		= mem_lseek, /* borrow this */
1433 	.read		= pagemap_read,
1434 	.open		= pagemap_open,
1435 	.release	= pagemap_release,
1436 };
1437 #endif /* CONFIG_PROC_PAGE_MONITOR */
1438 
1439 #ifdef CONFIG_NUMA
1440 
1441 struct numa_maps {
1442 	unsigned long pages;
1443 	unsigned long anon;
1444 	unsigned long active;
1445 	unsigned long writeback;
1446 	unsigned long mapcount_max;
1447 	unsigned long dirty;
1448 	unsigned long swapcache;
1449 	unsigned long node[MAX_NUMNODES];
1450 };
1451 
1452 struct numa_maps_private {
1453 	struct proc_maps_private proc_maps;
1454 	struct numa_maps md;
1455 };
1456 
1457 static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
1458 			unsigned long nr_pages)
1459 {
1460 	int count = page_mapcount(page);
1461 
1462 	md->pages += nr_pages;
1463 	if (pte_dirty || PageDirty(page))
1464 		md->dirty += nr_pages;
1465 
1466 	if (PageSwapCache(page))
1467 		md->swapcache += nr_pages;
1468 
1469 	if (PageActive(page) || PageUnevictable(page))
1470 		md->active += nr_pages;
1471 
1472 	if (PageWriteback(page))
1473 		md->writeback += nr_pages;
1474 
1475 	if (PageAnon(page))
1476 		md->anon += nr_pages;
1477 
1478 	if (count > md->mapcount_max)
1479 		md->mapcount_max = count;
1480 
1481 	md->node[page_to_nid(page)] += nr_pages;
1482 }
1483 
1484 static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
1485 		unsigned long addr)
1486 {
1487 	struct page *page;
1488 	int nid;
1489 
1490 	if (!pte_present(pte))
1491 		return NULL;
1492 
1493 	page = vm_normal_page(vma, addr, pte);
1494 	if (!page)
1495 		return NULL;
1496 
1497 	if (PageReserved(page))
1498 		return NULL;
1499 
1500 	nid = page_to_nid(page);
1501 	if (!node_isset(nid, node_states[N_MEMORY]))
1502 		return NULL;
1503 
1504 	return page;
1505 }
1506 
1507 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
1508 		unsigned long end, struct mm_walk *walk)
1509 {
1510 	struct numa_maps *md = walk->private;
1511 	struct vm_area_struct *vma = walk->vma;
1512 	spinlock_t *ptl;
1513 	pte_t *orig_pte;
1514 	pte_t *pte;
1515 
1516 	ptl = pmd_trans_huge_lock(pmd, vma);
1517 	if (ptl) {
1518 		pte_t huge_pte = *(pte_t *)pmd;
1519 		struct page *page;
1520 
1521 		page = can_gather_numa_stats(huge_pte, vma, addr);
1522 		if (page)
1523 			gather_stats(page, md, pte_dirty(huge_pte),
1524 				     HPAGE_PMD_SIZE/PAGE_SIZE);
1525 		spin_unlock(ptl);
1526 		return 0;
1527 	}
1528 
1529 	if (pmd_trans_unstable(pmd))
1530 		return 0;
1531 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
1532 	do {
1533 		struct page *page = can_gather_numa_stats(*pte, vma, addr);
1534 		if (!page)
1535 			continue;
1536 		gather_stats(page, md, pte_dirty(*pte), 1);
1537 
1538 	} while (pte++, addr += PAGE_SIZE, addr != end);
1539 	pte_unmap_unlock(orig_pte, ptl);
1540 	return 0;
1541 }
1542 #ifdef CONFIG_HUGETLB_PAGE
1543 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1544 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1545 {
1546 	pte_t huge_pte = huge_ptep_get(pte);
1547 	struct numa_maps *md;
1548 	struct page *page;
1549 
1550 	if (!pte_present(huge_pte))
1551 		return 0;
1552 
1553 	page = pte_page(huge_pte);
1554 	if (!page)
1555 		return 0;
1556 
1557 	md = walk->private;
1558 	gather_stats(page, md, pte_dirty(huge_pte), 1);
1559 	return 0;
1560 }
1561 
1562 #else
1563 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1564 		unsigned long addr, unsigned long end, struct mm_walk *walk)
1565 {
1566 	return 0;
1567 }
1568 #endif
1569 
1570 /*
1571  * Display pages allocated per node and memory policy via /proc.
1572  */
1573 static int show_numa_map(struct seq_file *m, void *v, int is_pid)
1574 {
1575 	struct numa_maps_private *numa_priv = m->private;
1576 	struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
1577 	struct vm_area_struct *vma = v;
1578 	struct numa_maps *md = &numa_priv->md;
1579 	struct file *file = vma->vm_file;
1580 	struct mm_struct *mm = vma->vm_mm;
1581 	struct mm_walk walk = {
1582 		.hugetlb_entry = gather_hugetlb_stats,
1583 		.pmd_entry = gather_pte_stats,
1584 		.private = md,
1585 		.mm = mm,
1586 	};
1587 	struct mempolicy *pol;
1588 	char buffer[64];
1589 	int nid;
1590 
1591 	if (!mm)
1592 		return 0;
1593 
1594 	/* Ensure we start with an empty set of numa_maps statistics. */
1595 	memset(md, 0, sizeof(*md));
1596 
1597 	pol = __get_vma_policy(vma, vma->vm_start);
1598 	if (pol) {
1599 		mpol_to_str(buffer, sizeof(buffer), pol);
1600 		mpol_cond_put(pol);
1601 	} else {
1602 		mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
1603 	}
1604 
1605 	seq_printf(m, "%08lx %s", vma->vm_start, buffer);
1606 
1607 	if (file) {
1608 		seq_puts(m, " file=");
1609 		seq_file_path(m, file, "\n\t= ");
1610 	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
1611 		seq_puts(m, " heap");
1612 	} else if (is_stack(proc_priv, vma, is_pid)) {
1613 		seq_puts(m, " stack");
1614 	}
1615 
1616 	if (is_vm_hugetlb_page(vma))
1617 		seq_puts(m, " huge");
1618 
1619 	/* mmap_sem is held by m_start */
1620 	walk_page_vma(vma, &walk);
1621 
1622 	if (!md->pages)
1623 		goto out;
1624 
1625 	if (md->anon)
1626 		seq_printf(m, " anon=%lu", md->anon);
1627 
1628 	if (md->dirty)
1629 		seq_printf(m, " dirty=%lu", md->dirty);
1630 
1631 	if (md->pages != md->anon && md->pages != md->dirty)
1632 		seq_printf(m, " mapped=%lu", md->pages);
1633 
1634 	if (md->mapcount_max > 1)
1635 		seq_printf(m, " mapmax=%lu", md->mapcount_max);
1636 
1637 	if (md->swapcache)
1638 		seq_printf(m, " swapcache=%lu", md->swapcache);
1639 
1640 	if (md->active < md->pages && !is_vm_hugetlb_page(vma))
1641 		seq_printf(m, " active=%lu", md->active);
1642 
1643 	if (md->writeback)
1644 		seq_printf(m, " writeback=%lu", md->writeback);
1645 
1646 	for_each_node_state(nid, N_MEMORY)
1647 		if (md->node[nid])
1648 			seq_printf(m, " N%d=%lu", nid, md->node[nid]);
1649 
1650 	seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
1651 out:
1652 	seq_putc(m, '\n');
1653 	m_cache_vma(m, vma);
1654 	return 0;
1655 }
1656 
1657 static int show_pid_numa_map(struct seq_file *m, void *v)
1658 {
1659 	return show_numa_map(m, v, 1);
1660 }
1661 
1662 static int show_tid_numa_map(struct seq_file *m, void *v)
1663 {
1664 	return show_numa_map(m, v, 0);
1665 }
1666 
1667 static const struct seq_operations proc_pid_numa_maps_op = {
1668 	.start  = m_start,
1669 	.next   = m_next,
1670 	.stop   = m_stop,
1671 	.show   = show_pid_numa_map,
1672 };
1673 
1674 static const struct seq_operations proc_tid_numa_maps_op = {
1675 	.start  = m_start,
1676 	.next   = m_next,
1677 	.stop   = m_stop,
1678 	.show   = show_tid_numa_map,
1679 };
1680 
1681 static int numa_maps_open(struct inode *inode, struct file *file,
1682 			  const struct seq_operations *ops)
1683 {
1684 	return proc_maps_open(inode, file, ops,
1685 				sizeof(struct numa_maps_private));
1686 }
1687 
1688 static int pid_numa_maps_open(struct inode *inode, struct file *file)
1689 {
1690 	return numa_maps_open(inode, file, &proc_pid_numa_maps_op);
1691 }
1692 
1693 static int tid_numa_maps_open(struct inode *inode, struct file *file)
1694 {
1695 	return numa_maps_open(inode, file, &proc_tid_numa_maps_op);
1696 }
1697 
1698 const struct file_operations proc_pid_numa_maps_operations = {
1699 	.open		= pid_numa_maps_open,
1700 	.read		= seq_read,
1701 	.llseek		= seq_lseek,
1702 	.release	= proc_map_release,
1703 };
1704 
1705 const struct file_operations proc_tid_numa_maps_operations = {
1706 	.open		= tid_numa_maps_open,
1707 	.read		= seq_read,
1708 	.llseek		= seq_lseek,
1709 	.release	= proc_map_release,
1710 };
1711 #endif /* CONFIG_NUMA */
1712