xref: /linux/fs/proc/task_mmu.c (revision a5766f11cfd3a0c03450d99c8fe548c2940be884)
1 #include <linux/mm.h>
2 #include <linux/hugetlb.h>
3 #include <linux/mount.h>
4 #include <linux/seq_file.h>
5 #include <linux/highmem.h>
6 #include <linux/ptrace.h>
7 #include <linux/pagemap.h>
8 #include <linux/mempolicy.h>
9 #include <linux/swap.h>
10 #include <linux/swapops.h>
11 
12 #include <asm/elf.h>
13 #include <asm/uaccess.h>
14 #include <asm/tlbflush.h>
15 #include "internal.h"
16 
17 void task_mem(struct seq_file *m, struct mm_struct *mm)
18 {
19 	unsigned long data, text, lib;
20 	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
21 
22 	/*
23 	 * Note: to minimize their overhead, mm maintains hiwater_vm and
24 	 * hiwater_rss only when about to *lower* total_vm or rss.  Any
25 	 * collector of these hiwater stats must therefore get total_vm
26 	 * and rss too, which will usually be the higher.  Barriers? not
27 	 * worth the effort, such snapshots can always be inconsistent.
28 	 */
29 	hiwater_vm = total_vm = mm->total_vm;
30 	if (hiwater_vm < mm->hiwater_vm)
31 		hiwater_vm = mm->hiwater_vm;
32 	hiwater_rss = total_rss = get_mm_rss(mm);
33 	if (hiwater_rss < mm->hiwater_rss)
34 		hiwater_rss = mm->hiwater_rss;
35 
36 	data = mm->total_vm - mm->shared_vm - mm->stack_vm;
37 	text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
38 	lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
39 	seq_printf(m,
40 		"VmPeak:\t%8lu kB\n"
41 		"VmSize:\t%8lu kB\n"
42 		"VmLck:\t%8lu kB\n"
43 		"VmHWM:\t%8lu kB\n"
44 		"VmRSS:\t%8lu kB\n"
45 		"VmData:\t%8lu kB\n"
46 		"VmStk:\t%8lu kB\n"
47 		"VmExe:\t%8lu kB\n"
48 		"VmLib:\t%8lu kB\n"
49 		"VmPTE:\t%8lu kB\n",
50 		hiwater_vm << (PAGE_SHIFT-10),
51 		(total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
52 		mm->locked_vm << (PAGE_SHIFT-10),
53 		hiwater_rss << (PAGE_SHIFT-10),
54 		total_rss << (PAGE_SHIFT-10),
55 		data << (PAGE_SHIFT-10),
56 		mm->stack_vm << (PAGE_SHIFT-10), text, lib,
57 		(PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10);
58 }
59 
60 unsigned long task_vsize(struct mm_struct *mm)
61 {
62 	return PAGE_SIZE * mm->total_vm;
63 }
64 
65 int task_statm(struct mm_struct *mm, int *shared, int *text,
66 	       int *data, int *resident)
67 {
68 	*shared = get_mm_counter(mm, file_rss);
69 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
70 								>> PAGE_SHIFT;
71 	*data = mm->total_vm - mm->shared_vm;
72 	*resident = *shared + get_mm_counter(mm, anon_rss);
73 	return mm->total_vm;
74 }
75 
76 static void pad_len_spaces(struct seq_file *m, int len)
77 {
78 	len = 25 + sizeof(void*) * 6 - len;
79 	if (len < 1)
80 		len = 1;
81 	seq_printf(m, "%*c", len, ' ');
82 }
83 
84 static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma)
85 {
86 	if (vma && vma != priv->tail_vma) {
87 		struct mm_struct *mm = vma->vm_mm;
88 		up_read(&mm->mmap_sem);
89 		mmput(mm);
90 	}
91 }
92 
93 static void *m_start(struct seq_file *m, loff_t *pos)
94 {
95 	struct proc_maps_private *priv = m->private;
96 	unsigned long last_addr = m->version;
97 	struct mm_struct *mm;
98 	struct vm_area_struct *vma, *tail_vma = NULL;
99 	loff_t l = *pos;
100 
101 	/* Clear the per syscall fields in priv */
102 	priv->task = NULL;
103 	priv->tail_vma = NULL;
104 
105 	/*
106 	 * We remember last_addr rather than next_addr to hit with
107 	 * mmap_cache most of the time. We have zero last_addr at
108 	 * the beginning and also after lseek. We will have -1 last_addr
109 	 * after the end of the vmas.
110 	 */
111 
112 	if (last_addr == -1UL)
113 		return NULL;
114 
115 	priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
116 	if (!priv->task)
117 		return NULL;
118 
119 	mm = mm_for_maps(priv->task);
120 	if (!mm)
121 		return NULL;
122 
123 	tail_vma = get_gate_vma(priv->task);
124 	priv->tail_vma = tail_vma;
125 
126 	/* Start with last addr hint */
127 	vma = find_vma(mm, last_addr);
128 	if (last_addr && vma) {
129 		vma = vma->vm_next;
130 		goto out;
131 	}
132 
133 	/*
134 	 * Check the vma index is within the range and do
135 	 * sequential scan until m_index.
136 	 */
137 	vma = NULL;
138 	if ((unsigned long)l < mm->map_count) {
139 		vma = mm->mmap;
140 		while (l-- && vma)
141 			vma = vma->vm_next;
142 		goto out;
143 	}
144 
145 	if (l != mm->map_count)
146 		tail_vma = NULL; /* After gate vma */
147 
148 out:
149 	if (vma)
150 		return vma;
151 
152 	/* End of vmas has been reached */
153 	m->version = (tail_vma != NULL)? 0: -1UL;
154 	up_read(&mm->mmap_sem);
155 	mmput(mm);
156 	return tail_vma;
157 }
158 
159 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
160 {
161 	struct proc_maps_private *priv = m->private;
162 	struct vm_area_struct *vma = v;
163 	struct vm_area_struct *tail_vma = priv->tail_vma;
164 
165 	(*pos)++;
166 	if (vma && (vma != tail_vma) && vma->vm_next)
167 		return vma->vm_next;
168 	vma_stop(priv, vma);
169 	return (vma != tail_vma)? tail_vma: NULL;
170 }
171 
172 static void m_stop(struct seq_file *m, void *v)
173 {
174 	struct proc_maps_private *priv = m->private;
175 	struct vm_area_struct *vma = v;
176 
177 	vma_stop(priv, vma);
178 	if (priv->task)
179 		put_task_struct(priv->task);
180 }
181 
182 static int do_maps_open(struct inode *inode, struct file *file,
183 			const struct seq_operations *ops)
184 {
185 	struct proc_maps_private *priv;
186 	int ret = -ENOMEM;
187 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
188 	if (priv) {
189 		priv->pid = proc_pid(inode);
190 		ret = seq_open(file, ops);
191 		if (!ret) {
192 			struct seq_file *m = file->private_data;
193 			m->private = priv;
194 		} else {
195 			kfree(priv);
196 		}
197 	}
198 	return ret;
199 }
200 
201 static int show_map(struct seq_file *m, void *v)
202 {
203 	struct proc_maps_private *priv = m->private;
204 	struct task_struct *task = priv->task;
205 	struct vm_area_struct *vma = v;
206 	struct mm_struct *mm = vma->vm_mm;
207 	struct file *file = vma->vm_file;
208 	int flags = vma->vm_flags;
209 	unsigned long ino = 0;
210 	dev_t dev = 0;
211 	int len;
212 
213 	if (file) {
214 		struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
215 		dev = inode->i_sb->s_dev;
216 		ino = inode->i_ino;
217 	}
218 
219 	seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
220 			vma->vm_start,
221 			vma->vm_end,
222 			flags & VM_READ ? 'r' : '-',
223 			flags & VM_WRITE ? 'w' : '-',
224 			flags & VM_EXEC ? 'x' : '-',
225 			flags & VM_MAYSHARE ? 's' : 'p',
226 			((loff_t)vma->vm_pgoff) << PAGE_SHIFT,
227 			MAJOR(dev), MINOR(dev), ino, &len);
228 
229 	/*
230 	 * Print the dentry name for named mappings, and a
231 	 * special [heap] marker for the heap:
232 	 */
233 	if (file) {
234 		pad_len_spaces(m, len);
235 		seq_path(m, &file->f_path, "\n");
236 	} else {
237 		const char *name = arch_vma_name(vma);
238 		if (!name) {
239 			if (mm) {
240 				if (vma->vm_start <= mm->start_brk &&
241 						vma->vm_end >= mm->brk) {
242 					name = "[heap]";
243 				} else if (vma->vm_start <= mm->start_stack &&
244 					   vma->vm_end >= mm->start_stack) {
245 					name = "[stack]";
246 				}
247 			} else {
248 				name = "[vdso]";
249 			}
250 		}
251 		if (name) {
252 			pad_len_spaces(m, len);
253 			seq_puts(m, name);
254 		}
255 	}
256 	seq_putc(m, '\n');
257 
258 	if (m->count < m->size)  /* vma is copied successfully */
259 		m->version = (vma != get_gate_vma(task))? vma->vm_start: 0;
260 	return 0;
261 }
262 
263 static const struct seq_operations proc_pid_maps_op = {
264 	.start	= m_start,
265 	.next	= m_next,
266 	.stop	= m_stop,
267 	.show	= show_map
268 };
269 
270 static int maps_open(struct inode *inode, struct file *file)
271 {
272 	return do_maps_open(inode, file, &proc_pid_maps_op);
273 }
274 
275 const struct file_operations proc_maps_operations = {
276 	.open		= maps_open,
277 	.read		= seq_read,
278 	.llseek		= seq_lseek,
279 	.release	= seq_release_private,
280 };
281 
282 /*
283  * Proportional Set Size(PSS): my share of RSS.
284  *
285  * PSS of a process is the count of pages it has in memory, where each
286  * page is divided by the number of processes sharing it.  So if a
287  * process has 1000 pages all to itself, and 1000 shared with one other
288  * process, its PSS will be 1500.
289  *
290  * To keep (accumulated) division errors low, we adopt a 64bit
291  * fixed-point pss counter to minimize division errors. So (pss >>
292  * PSS_SHIFT) would be the real byte count.
293  *
294  * A shift of 12 before division means (assuming 4K page size):
295  * 	- 1M 3-user-pages add up to 8KB errors;
296  * 	- supports mapcount up to 2^24, or 16M;
297  * 	- supports PSS up to 2^52 bytes, or 4PB.
298  */
299 #define PSS_SHIFT 12
300 
301 #ifdef CONFIG_PROC_PAGE_MONITOR
302 struct mem_size_stats {
303 	struct vm_area_struct *vma;
304 	unsigned long resident;
305 	unsigned long shared_clean;
306 	unsigned long shared_dirty;
307 	unsigned long private_clean;
308 	unsigned long private_dirty;
309 	unsigned long referenced;
310 	unsigned long swap;
311 	u64 pss;
312 };
313 
314 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
315 			   struct mm_walk *walk)
316 {
317 	struct mem_size_stats *mss = walk->private;
318 	struct vm_area_struct *vma = mss->vma;
319 	pte_t *pte, ptent;
320 	spinlock_t *ptl;
321 	struct page *page;
322 	int mapcount;
323 
324 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
325 	for (; addr != end; pte++, addr += PAGE_SIZE) {
326 		ptent = *pte;
327 
328 		if (is_swap_pte(ptent)) {
329 			mss->swap += PAGE_SIZE;
330 			continue;
331 		}
332 
333 		if (!pte_present(ptent))
334 			continue;
335 
336 		mss->resident += PAGE_SIZE;
337 
338 		page = vm_normal_page(vma, addr, ptent);
339 		if (!page)
340 			continue;
341 
342 		/* Accumulate the size in pages that have been accessed. */
343 		if (pte_young(ptent) || PageReferenced(page))
344 			mss->referenced += PAGE_SIZE;
345 		mapcount = page_mapcount(page);
346 		if (mapcount >= 2) {
347 			if (pte_dirty(ptent))
348 				mss->shared_dirty += PAGE_SIZE;
349 			else
350 				mss->shared_clean += PAGE_SIZE;
351 			mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
352 		} else {
353 			if (pte_dirty(ptent))
354 				mss->private_dirty += PAGE_SIZE;
355 			else
356 				mss->private_clean += PAGE_SIZE;
357 			mss->pss += (PAGE_SIZE << PSS_SHIFT);
358 		}
359 	}
360 	pte_unmap_unlock(pte - 1, ptl);
361 	cond_resched();
362 	return 0;
363 }
364 
365 static int show_smap(struct seq_file *m, void *v)
366 {
367 	struct vm_area_struct *vma = v;
368 	struct mem_size_stats mss;
369 	int ret;
370 	struct mm_walk smaps_walk = {
371 		.pmd_entry = smaps_pte_range,
372 		.mm = vma->vm_mm,
373 		.private = &mss,
374 	};
375 
376 	memset(&mss, 0, sizeof mss);
377 	mss.vma = vma;
378 	if (vma->vm_mm && !is_vm_hugetlb_page(vma))
379 		walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
380 
381 	ret = show_map(m, v);
382 	if (ret)
383 		return ret;
384 
385 	seq_printf(m,
386 		   "Size:           %8lu kB\n"
387 		   "Rss:            %8lu kB\n"
388 		   "Pss:            %8lu kB\n"
389 		   "Shared_Clean:   %8lu kB\n"
390 		   "Shared_Dirty:   %8lu kB\n"
391 		   "Private_Clean:  %8lu kB\n"
392 		   "Private_Dirty:  %8lu kB\n"
393 		   "Referenced:     %8lu kB\n"
394 		   "Swap:           %8lu kB\n",
395 		   (vma->vm_end - vma->vm_start) >> 10,
396 		   mss.resident >> 10,
397 		   (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
398 		   mss.shared_clean  >> 10,
399 		   mss.shared_dirty  >> 10,
400 		   mss.private_clean >> 10,
401 		   mss.private_dirty >> 10,
402 		   mss.referenced >> 10,
403 		   mss.swap >> 10);
404 
405 	return ret;
406 }
407 
408 static const struct seq_operations proc_pid_smaps_op = {
409 	.start	= m_start,
410 	.next	= m_next,
411 	.stop	= m_stop,
412 	.show	= show_smap
413 };
414 
415 static int smaps_open(struct inode *inode, struct file *file)
416 {
417 	return do_maps_open(inode, file, &proc_pid_smaps_op);
418 }
419 
420 const struct file_operations proc_smaps_operations = {
421 	.open		= smaps_open,
422 	.read		= seq_read,
423 	.llseek		= seq_lseek,
424 	.release	= seq_release_private,
425 };
426 
427 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
428 				unsigned long end, struct mm_walk *walk)
429 {
430 	struct vm_area_struct *vma = walk->private;
431 	pte_t *pte, ptent;
432 	spinlock_t *ptl;
433 	struct page *page;
434 
435 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
436 	for (; addr != end; pte++, addr += PAGE_SIZE) {
437 		ptent = *pte;
438 		if (!pte_present(ptent))
439 			continue;
440 
441 		page = vm_normal_page(vma, addr, ptent);
442 		if (!page)
443 			continue;
444 
445 		/* Clear accessed and referenced bits. */
446 		ptep_test_and_clear_young(vma, addr, pte);
447 		ClearPageReferenced(page);
448 	}
449 	pte_unmap_unlock(pte - 1, ptl);
450 	cond_resched();
451 	return 0;
452 }
453 
454 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
455 				size_t count, loff_t *ppos)
456 {
457 	struct task_struct *task;
458 	char buffer[PROC_NUMBUF], *end;
459 	struct mm_struct *mm;
460 	struct vm_area_struct *vma;
461 
462 	memset(buffer, 0, sizeof(buffer));
463 	if (count > sizeof(buffer) - 1)
464 		count = sizeof(buffer) - 1;
465 	if (copy_from_user(buffer, buf, count))
466 		return -EFAULT;
467 	if (!simple_strtol(buffer, &end, 0))
468 		return -EINVAL;
469 	if (*end == '\n')
470 		end++;
471 	task = get_proc_task(file->f_path.dentry->d_inode);
472 	if (!task)
473 		return -ESRCH;
474 	mm = get_task_mm(task);
475 	if (mm) {
476 		struct mm_walk clear_refs_walk = {
477 			.pmd_entry = clear_refs_pte_range,
478 			.mm = mm,
479 		};
480 		down_read(&mm->mmap_sem);
481 		for (vma = mm->mmap; vma; vma = vma->vm_next) {
482 			clear_refs_walk.private = vma;
483 			if (!is_vm_hugetlb_page(vma))
484 				walk_page_range(vma->vm_start, vma->vm_end,
485 						&clear_refs_walk);
486 		}
487 		flush_tlb_mm(mm);
488 		up_read(&mm->mmap_sem);
489 		mmput(mm);
490 	}
491 	put_task_struct(task);
492 	if (end - buffer == 0)
493 		return -EIO;
494 	return end - buffer;
495 }
496 
497 const struct file_operations proc_clear_refs_operations = {
498 	.write		= clear_refs_write,
499 };
500 
501 struct pagemapread {
502 	u64 __user *out, *end;
503 };
504 
505 #define PM_ENTRY_BYTES      sizeof(u64)
506 #define PM_STATUS_BITS      3
507 #define PM_STATUS_OFFSET    (64 - PM_STATUS_BITS)
508 #define PM_STATUS_MASK      (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
509 #define PM_STATUS(nr)       (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
510 #define PM_PSHIFT_BITS      6
511 #define PM_PSHIFT_OFFSET    (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
512 #define PM_PSHIFT_MASK      (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
513 #define PM_PSHIFT(x)        (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
514 #define PM_PFRAME_MASK      ((1LL << PM_PSHIFT_OFFSET) - 1)
515 #define PM_PFRAME(x)        ((x) & PM_PFRAME_MASK)
516 
517 #define PM_PRESENT          PM_STATUS(4LL)
518 #define PM_SWAP             PM_STATUS(2LL)
519 #define PM_NOT_PRESENT      PM_PSHIFT(PAGE_SHIFT)
520 #define PM_END_OF_BUFFER    1
521 
522 static int add_to_pagemap(unsigned long addr, u64 pfn,
523 			  struct pagemapread *pm)
524 {
525 	if (put_user(pfn, pm->out))
526 		return -EFAULT;
527 	pm->out++;
528 	if (pm->out >= pm->end)
529 		return PM_END_OF_BUFFER;
530 	return 0;
531 }
532 
533 static int pagemap_pte_hole(unsigned long start, unsigned long end,
534 				struct mm_walk *walk)
535 {
536 	struct pagemapread *pm = walk->private;
537 	unsigned long addr;
538 	int err = 0;
539 	for (addr = start; addr < end; addr += PAGE_SIZE) {
540 		err = add_to_pagemap(addr, PM_NOT_PRESENT, pm);
541 		if (err)
542 			break;
543 	}
544 	return err;
545 }
546 
547 static u64 swap_pte_to_pagemap_entry(pte_t pte)
548 {
549 	swp_entry_t e = pte_to_swp_entry(pte);
550 	return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
551 }
552 
553 static unsigned long pte_to_pagemap_entry(pte_t pte)
554 {
555 	unsigned long pme = 0;
556 	if (is_swap_pte(pte))
557 		pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte))
558 			| PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;
559 	else if (pte_present(pte))
560 		pme = PM_PFRAME(pte_pfn(pte))
561 			| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;
562 	return pme;
563 }
564 
565 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
566 			     struct mm_walk *walk)
567 {
568 	struct vm_area_struct *vma;
569 	struct pagemapread *pm = walk->private;
570 	pte_t *pte;
571 	int err = 0;
572 
573 	/* find the first VMA at or above 'addr' */
574 	vma = find_vma(walk->mm, addr);
575 	for (; addr != end; addr += PAGE_SIZE) {
576 		u64 pfn = PM_NOT_PRESENT;
577 
578 		/* check to see if we've left 'vma' behind
579 		 * and need a new, higher one */
580 		if (vma && (addr >= vma->vm_end))
581 			vma = find_vma(walk->mm, addr);
582 
583 		/* check that 'vma' actually covers this address,
584 		 * and that it isn't a huge page vma */
585 		if (vma && (vma->vm_start <= addr) &&
586 		    !is_vm_hugetlb_page(vma)) {
587 			pte = pte_offset_map(pmd, addr);
588 			pfn = pte_to_pagemap_entry(*pte);
589 			/* unmap before userspace copy */
590 			pte_unmap(pte);
591 		}
592 		err = add_to_pagemap(addr, pfn, pm);
593 		if (err)
594 			return err;
595 	}
596 
597 	cond_resched();
598 
599 	return err;
600 }
601 
602 /*
603  * /proc/pid/pagemap - an array mapping virtual pages to pfns
604  *
605  * For each page in the address space, this file contains one 64-bit entry
606  * consisting of the following:
607  *
608  * Bits 0-55  page frame number (PFN) if present
609  * Bits 0-4   swap type if swapped
610  * Bits 5-55  swap offset if swapped
611  * Bits 55-60 page shift (page size = 1<<page shift)
612  * Bit  61    reserved for future use
613  * Bit  62    page swapped
614  * Bit  63    page present
615  *
616  * If the page is not present but in swap, then the PFN contains an
617  * encoding of the swap file number and the page's offset into the
618  * swap. Unmapped pages return a null PFN. This allows determining
619  * precisely which pages are mapped (or in swap) and comparing mapped
620  * pages between processes.
621  *
622  * Efficient users of this interface will use /proc/pid/maps to
623  * determine which areas of memory are actually mapped and llseek to
624  * skip over unmapped regions.
625  */
626 static ssize_t pagemap_read(struct file *file, char __user *buf,
627 			    size_t count, loff_t *ppos)
628 {
629 	struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
630 	struct page **pages, *page;
631 	unsigned long uaddr, uend;
632 	struct mm_struct *mm;
633 	struct pagemapread pm;
634 	int pagecount;
635 	int ret = -ESRCH;
636 	struct mm_walk pagemap_walk = {};
637 	unsigned long src;
638 	unsigned long svpfn;
639 	unsigned long start_vaddr;
640 	unsigned long end_vaddr;
641 
642 	if (!task)
643 		goto out;
644 
645 	ret = -EACCES;
646 	if (!ptrace_may_access(task, PTRACE_MODE_READ))
647 		goto out_task;
648 
649 	ret = -EINVAL;
650 	/* file position must be aligned */
651 	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
652 		goto out_task;
653 
654 	ret = 0;
655 	mm = get_task_mm(task);
656 	if (!mm)
657 		goto out_task;
658 
659 
660 	uaddr = (unsigned long)buf & PAGE_MASK;
661 	uend = (unsigned long)(buf + count);
662 	pagecount = (PAGE_ALIGN(uend) - uaddr) / PAGE_SIZE;
663 	ret = 0;
664 	if (pagecount == 0)
665 		goto out_mm;
666 	pages = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);
667 	ret = -ENOMEM;
668 	if (!pages)
669 		goto out_mm;
670 
671 	down_read(&current->mm->mmap_sem);
672 	ret = get_user_pages(current, current->mm, uaddr, pagecount,
673 			     1, 0, pages, NULL);
674 	up_read(&current->mm->mmap_sem);
675 
676 	if (ret < 0)
677 		goto out_free;
678 
679 	if (ret != pagecount) {
680 		pagecount = ret;
681 		ret = -EFAULT;
682 		goto out_pages;
683 	}
684 
685 	pm.out = (u64 *)buf;
686 	pm.end = (u64 *)(buf + count);
687 
688 	pagemap_walk.pmd_entry = pagemap_pte_range;
689 	pagemap_walk.pte_hole = pagemap_pte_hole;
690 	pagemap_walk.mm = mm;
691 	pagemap_walk.private = &pm;
692 
693 	src = *ppos;
694 	svpfn = src / PM_ENTRY_BYTES;
695 	start_vaddr = svpfn << PAGE_SHIFT;
696 	end_vaddr = TASK_SIZE_OF(task);
697 
698 	/* watch out for wraparound */
699 	if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT)
700 		start_vaddr = end_vaddr;
701 
702 	/*
703 	 * The odds are that this will stop walking way
704 	 * before end_vaddr, because the length of the
705 	 * user buffer is tracked in "pm", and the walk
706 	 * will stop when we hit the end of the buffer.
707 	 */
708 	ret = walk_page_range(start_vaddr, end_vaddr, &pagemap_walk);
709 	if (ret == PM_END_OF_BUFFER)
710 		ret = 0;
711 	/* don't need mmap_sem for these, but this looks cleaner */
712 	*ppos += (char *)pm.out - buf;
713 	if (!ret)
714 		ret = (char *)pm.out - buf;
715 
716 out_pages:
717 	for (; pagecount; pagecount--) {
718 		page = pages[pagecount-1];
719 		if (!PageReserved(page))
720 			SetPageDirty(page);
721 		page_cache_release(page);
722 	}
723 out_free:
724 	kfree(pages);
725 out_mm:
726 	mmput(mm);
727 out_task:
728 	put_task_struct(task);
729 out:
730 	return ret;
731 }
732 
733 const struct file_operations proc_pagemap_operations = {
734 	.llseek		= mem_lseek, /* borrow this */
735 	.read		= pagemap_read,
736 };
737 #endif /* CONFIG_PROC_PAGE_MONITOR */
738 
739 #ifdef CONFIG_NUMA
740 extern int show_numa_map(struct seq_file *m, void *v);
741 
742 static const struct seq_operations proc_pid_numa_maps_op = {
743         .start  = m_start,
744         .next   = m_next,
745         .stop   = m_stop,
746         .show   = show_numa_map,
747 };
748 
749 static int numa_maps_open(struct inode *inode, struct file *file)
750 {
751 	return do_maps_open(inode, file, &proc_pid_numa_maps_op);
752 }
753 
754 const struct file_operations proc_numa_maps_operations = {
755 	.open		= numa_maps_open,
756 	.read		= seq_read,
757 	.llseek		= seq_lseek,
758 	.release	= seq_release_private,
759 };
760 #endif
761