Aquaris-M10-4G/fs/proc/page.c

#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ksm.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/hugetlb.h>
#include <linux/kernel-page-flags.h>
#include <asm/uaccess.h>
#include "internal.h"

#ifdef CONFIG_SWAP
#include <linux/swap.h>
#include <linux/swapops.h>
#endif

#define KPMSIZE sizeof(u64)
#define KPMMASK (KPMSIZE - 1)

/* /proc/kpagecount - an array exposing page counts
 *
 * Each entry is a u64 representing the corresponding
 * physical page count.
 */
static ssize_t kpagecount_read(struct file *file, char __user *buf,
			     size_t count, loff_t *ppos)
{
	u64 __user *out = (u64 __user *)buf;
	struct page *ppage;
	unsigned long src = *ppos;
	unsigned long pfn;
	unsigned long max_pfn_kpmsize = max_pfn * KPMSIZE;
	ssize_t ret = 0;
	u64 pcount;

	pfn = src / KPMSIZE;
	if (src != max_pfn_kpmsize)
		count = min_t(size_t, count, max_pfn_kpmsize - src);

	if (src & KPMMASK || count & KPMMASK)
		return -EINVAL;

	while (count > 0) {
		if (pfn_valid(pfn))
			ppage = pfn_to_page(pfn);
		else
			ppage = NULL;
		if (!ppage || PageSlab(ppage))
			pcount = 0;
		else
			pcount = page_mapcount(ppage);

		if (put_user(pcount, out)) {
			ret = -EFAULT;
			break;
		}

		pfn++;
		out++;
		count -= KPMSIZE;
	}

	*ppos += (char __user *)out - buf;
	if (!ret)
		ret = (char __user *)out - buf;
	return ret;
}

static const struct file_operations proc_kpagecount_operations = {
	.llseek = mem_lseek,
	.read = kpagecount_read,
};

/* M for pswap interface */
#ifdef CONFIG_SWAP
static inline unsigned char swap_count(unsigned char ent)
{
	return ent & ~SWAP_HAS_CACHE;	/* may include SWAP_HAS_CONT flag */
}

/* /proc/kpageswapn - an array exposing page swap counts
 *
 * Each entry is a u64 representing the corresponding
 * physical page swap count.
 */
static ssize_t kpageswapn_read(struct file *file, char __user *buf,
			     size_t count, loff_t *ppos)
{
	u64 __user *out = (u64 __user *)buf;
	unsigned long src = *ppos, dst;
	swp_entry_t swap_entry;
	ssize_t ret = 0;
	struct swap_info_struct *p;

	dst = src / KPMSIZE;
	/* Format the swap entry from the corresponding pagemap value */
	swap_entry = swp_entry(dst >> (SWP_TYPE_SHIFT(swap_entry) + RADIX_TREE_EXCEPTIONAL_SHIFT),
							dst & SWP_OFFSET_MASK(swap_entry));

	/*pr_info("kpageswapn_read src: %lx\n", src); */
	/*pr_info("kpageswapn_read swap entry: %lx\n", swap_entry.val); */

	if (src & KPMMASK || count & KPMMASK) {
		pr_err("kpageswapn_read return EINVAL\n");
		return -EINVAL;
	}

	p = swap_info_get(swap_entry);
	if (p) {
		u64 swapcount = swap_count(p->swap_map[swp_offset(swap_entry)]);

		if (put_user(swapcount, out)) {
			pr_err("pageswapn_read put user failed\n");
			ret = -EFAULT;
		}
		swap_info_unlock(p);
	} else {
		pr_err("kpageswapn_read swap_info_get failed\n");
		ret = -EFAULT;
	}

	if (!ret) {
		*ppos += KPMSIZE;
		ret = KPMSIZE;
	}
	return ret;
}

static const struct file_operations proc_kpageswapn_operations = {
	.llseek = mem_lseek,
	.read = kpageswapn_read,
};
#endif /* CONFIG_SWAP*/

/* /proc/kpageflags - an array exposing page flags
 *
 * Each entry is a u64 representing the corresponding
 * physical page flags.
 */

static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
{
	return ((kflags >> kbit) & 1) << ubit;
}

u64 stable_page_flags(struct page *page)
{
	u64 k;
	u64 u;

	/*
	 * pseudo flag: KPF_NOPAGE
	 * it differentiates a memory hole from a page with no flags
	 */
	if (!page)
		return 1 << KPF_NOPAGE;

	k = page->flags;
	u = 0;

	/*
	 * pseudo flags for the well known (anonymous) memory mapped pages
	 *
	 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
	 * simple test in page_mapped() is not enough.
	 */
	if (!PageSlab(page) && page_mapped(page))
		u |= 1 << KPF_MMAP;
	if (PageAnon(page))
		u |= 1 << KPF_ANON;
	if (PageKsm(page))
		u |= 1 << KPF_KSM;

	/*
	 * compound pages: export both head/tail info
	 * they together define a compound page's start/end pos and order
	 */
	if (PageHead(page))
		u |= 1 << KPF_COMPOUND_HEAD;
	if (PageTail(page))
		u |= 1 << KPF_COMPOUND_TAIL;
	if (PageHuge(page))
		u |= 1 << KPF_HUGE;
	/*
	 * PageTransCompound can be true for non-huge compound pages (slab
	 * pages or pages allocated by drivers with __GFP_COMP) because it
	 * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
	 * to make sure a given page is a thp, not a non-huge compound page.
	 */
	else if (PageTransCompound(page) && (PageLRU(compound_head(page)) ||
					     PageAnon(compound_head(page))))
		u |= 1 << KPF_THP;

	/*
	 * Caveats on high order pages: page->_count will only be set
	 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
	 * SLOB won't set PG_slab at all on compound pages.
	 */
	if (PageBuddy(page))
		u |= 1 << KPF_BUDDY;

	if (PageBalloon(page))
		u |= 1 << KPF_BALLOON;

	u |= kpf_copy_bit(k, KPF_LOCKED,	PG_locked);

	u |= kpf_copy_bit(k, KPF_SLAB,		PG_slab);

	u |= kpf_copy_bit(k, KPF_ERROR,		PG_error);
	u |= kpf_copy_bit(k, KPF_DIRTY,		PG_dirty);
	u |= kpf_copy_bit(k, KPF_UPTODATE,	PG_uptodate);
	u |= kpf_copy_bit(k, KPF_WRITEBACK,	PG_writeback);

	u |= kpf_copy_bit(k, KPF_LRU,		PG_lru);
	u |= kpf_copy_bit(k, KPF_REFERENCED,	PG_referenced);
	u |= kpf_copy_bit(k, KPF_ACTIVE,	PG_active);
	u |= kpf_copy_bit(k, KPF_RECLAIM,	PG_reclaim);

	u |= kpf_copy_bit(k, KPF_SWAPCACHE,	PG_swapcache);
	u |= kpf_copy_bit(k, KPF_SWAPBACKED,	PG_swapbacked);

	u |= kpf_copy_bit(k, KPF_UNEVICTABLE,	PG_unevictable);
	u |= kpf_copy_bit(k, KPF_MLOCKED,	PG_mlocked);

#ifdef CONFIG_MEMORY_FAILURE
	u |= kpf_copy_bit(k, KPF_HWPOISON,	PG_hwpoison);
#endif

#ifdef CONFIG_ARCH_USES_PG_UNCACHED
	u |= kpf_copy_bit(k, KPF_UNCACHED,	PG_uncached);
#endif

	u |= kpf_copy_bit(k, KPF_RESERVED,	PG_reserved);
	u |= kpf_copy_bit(k, KPF_MAPPEDTODISK,	PG_mappedtodisk);
	u |= kpf_copy_bit(k, KPF_PRIVATE,	PG_private);
	u |= kpf_copy_bit(k, KPF_PRIVATE_2,	PG_private_2);
	u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE,	PG_owner_priv_1);
	u |= kpf_copy_bit(k, KPF_ARCH,		PG_arch_1);

	return u;
};

static ssize_t kpageflags_read(struct file *file, char __user *buf,
			     size_t count, loff_t *ppos)
{
	u64 __user *out = (u64 __user *)buf;
	struct page *ppage;
	unsigned long src = *ppos;
	unsigned long pfn;
	unsigned long max_pfn_kpmsize = max_pfn * KPMSIZE;
	ssize_t ret = 0;

	pfn = src / KPMSIZE;
	if (src != max_pfn_kpmsize)
		count = min_t(unsigned long, count, max_pfn_kpmsize - src);

	if (src & KPMMASK || count & KPMMASK)
		return -EINVAL;

	while (count > 0) {
		if (pfn_valid(pfn))
			ppage = pfn_to_page(pfn);
		else
			ppage = NULL;

		if (put_user(stable_page_flags(ppage), out)) {
			ret = -EFAULT;
			break;
		}

		pfn++;
		out++;
		count -= KPMSIZE;
	}

	*ppos += (char __user *)out - buf;
	if (!ret)
		ret = (char __user *)out - buf;
	return ret;
}

static const struct file_operations proc_kpageflags_operations = {
	.llseek = mem_lseek,
	.read = kpageflags_read,
};

static int __init proc_page_init(void)
{
	proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
#ifdef CONFIG_SWAP /* M for pswap interface */
	proc_create("kpageswapn", S_IRUSR, NULL, &proc_kpageswapn_operations);
#endif /* CONFIG_SWAP*/
	proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
	return 0;
}
fs_initcall(proc_page_init);