fs/proc/page.c

   1 #include <linux/bootmem.h>
   2 #include <linux/compiler.h>
   3 #include <linux/fs.h>
   4 #include <linux/init.h>
   5 #include <linux/ksm.h>
   6 #include <linux/mm.h>
   7 #include <linux/mmzone.h>
   8 #include <linux/proc_fs.h>
   9 #include <linux/seq_file.h>
  10 #include <linux/hugetlb.h>
  11 #include <linux/kernel-page-flags.h>
  12 #include <linux/swap.h>
  13 #include <linux/swapops.h>
  14 #include <asm/uaccess.h>
  15 #include "internal.h"
  16
  17 #define KPMSIZE sizeof(u64)
  18 #define KPMMASK (KPMSIZE - 1)
  19
  20 /* /proc/kpagecount - an array exposing page counts
  21  *
  22  * Each entry is a u64 representing the corresponding
  23  * physical page count.
  24  */
  25 static ssize_t kpagecount_read(struct file *file, char __user *buf,
  26                              size_t count, loff_t *ppos)
  27 {
  28         u64 __user *out = (u64 __user *)buf;
  29         struct page *ppage;
  30         unsigned long src = *ppos;
  31         unsigned long pfn;
  32         unsigned long max_pfn_kpmsize = max_pfn * KPMSIZE;
  33         ssize_t ret = 0;
  34         u64 pcount;
  35
  36         pfn = src / KPMSIZE;
  37         if(src != max_pfn_kpmsize){
  38         count = min_t(size_t, count, max_pfn_kpmsize - src);
  39         }
  40
  41         if (src & KPMMASK || count & KPMMASK)
  42                 return -EINVAL;
  43
  44         while (count > 0) {
  45                 if (pfn_valid(pfn))
  46                         ppage = pfn_to_page(pfn);
  47                 else
  48                         ppage = NULL;
  49                 if (!ppage || PageSlab(ppage))
  50                         pcount = 0;
  51                 else
  52                         pcount = page_mapcount(ppage);
  53
  54                 if (put_user(pcount, out)) {
  55                         ret = -EFAULT;
  56                         break;
  57                 }
  58
  59                 pfn++;
  60                 out++;
  61                 count -= KPMSIZE;
  62         }
  63
  64         *ppos += (char __user *)out - buf;
  65         if (!ret)
  66                 ret = (char __user *)out - buf;
  67         return ret;
  68 }
  69
  70 static const struct file_operations proc_kpagecount_operations = {
  71         .llseek = mem_lseek,
  72         .read = kpagecount_read,
  73 };
  74
  75 #ifdef CONFIG_SWAP
  76 extern struct swap_info_struct *swap_info_get(swp_entry_t entry);
  77 extern void swap_info_unlock(struct swap_info_struct *si);
  78
  79 static inline unsigned char swap_count(unsigned char ent)
  80 {
  81         return ent & ~SWAP_HAS_CACHE;   /* may include SWAP_HAS_CONT flag */
  82 }
  83
  84 /* /proc/kpageswapn - an array exposing page swap counts
  85  *
  86  * Each entry is a u64 representing the corresponding
  87  * physical page swap count.
  88  */
  89 static ssize_t kpageswapn_read(struct file *file, char __user *buf,
  90                              size_t count, loff_t *ppos)
  91 {
  92         u64 __user *out = (u64 __user *)buf;
  93         unsigned long src = *ppos;
  94         swp_entry_t swap_entry;
  95         ssize_t ret = 0;
  96         struct swap_info_struct *p;
  97
  98         swap_entry.val = src / KPMSIZE;
  99         //printk(KERN_INFO "kpageswapn_read src: %lx\n", src);
 100         //printk(KERN_INFO "kpageswapn_read swap entry: %lx\n", swap_entry.val);
 101
 102         if (src & KPMMASK || count & KPMMASK) {
 103                 printk(KERN_INFO "kpageswapn_read return EINVAL\n");
 104                 return -EINVAL;
 105         }
 106
 107         p = swap_info_get(swap_entry);
 108         if (p) {
 109                 u64 swapcount = swap_count(p->swap_map[swp_offset(swap_entry)]);
 110                 if (put_user(swapcount, out)) {
 111                         printk(KERN_INFO "kpageswapn_read put user failed\n");
 112                         ret = -EFAULT;
 113                 }
 114                 swap_info_unlock(p);
 115         } else {
 116                 printk(KERN_INFO "kpageswapn_read swap_info_get failed\n");
 117                 ret = -EFAULT;
 118         }
 119
 120         if (!ret) {
 121                 *ppos += KPMSIZE;
 122                 ret = KPMSIZE;
 123         }
 124         return ret;
 125 }
 126
 127 static const struct file_operations proc_kpageswapn_operations = {
 128         .llseek = mem_lseek,
 129         .read = kpageswapn_read,
 130 };
 131 #endif // CONFIG_SWAP
 132
 133 /* /proc/kpageflags - an array exposing page flags
 134  *
 135  * Each entry is a u64 representing the corresponding
 136  * physical page flags.
 137  */
 138
 139 static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
 140 {
 141         return ((kflags >> kbit) & 1) << ubit;
 142 }
 143
 144 u64 stable_page_flags(struct page *page)
 145 {
 146         u64 k;
 147         u64 u;
 148
 149         /*
 150          * pseudo flag: KPF_NOPAGE
 151          * it differentiates a memory hole from a page with no flags
 152          */
 153         if (!page)
 154                 return 1 << KPF_NOPAGE;
 155
 156         k = page->flags;
 157         u = 0;
 158
 159         /*
 160          * pseudo flags for the well known (anonymous) memory mapped pages
 161          *
 162          * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
 163          * simple test in page_mapped() is not enough.
 164          */
 165         if (!PageSlab(page) && page_mapped(page))
 166                 u |= 1 << KPF_MMAP;
 167         if (PageAnon(page))
 168                 u |= 1 << KPF_ANON;
 169         if (PageKsm(page))
 170                 u |= 1 << KPF_KSM;
 171
 172         /*
 173          * compound pages: export both head/tail info
 174          * they together define a compound page's start/end pos and order
 175          */
 176         if (PageHead(page))
 177                 u |= 1 << KPF_COMPOUND_HEAD;
 178         if (PageTail(page))
 179                 u |= 1 << KPF_COMPOUND_TAIL;
 180         if (PageHuge(page))
 181                 u |= 1 << KPF_HUGE;
 182         /*
 183          * PageTransCompound can be true for non-huge compound pages (slab
 184          * pages or pages allocated by drivers with __GFP_COMP) because it
 185          * just checks PG_head/PG_tail, so we need to check PageLRU to make
 186          * sure a given page is a thp, not a non-huge compound page.
 187          */
 188         else if (PageTransCompound(page) && PageLRU(compound_head(page)))
 189                 u |= 1 << KPF_THP;
 190
 191         /*
 192          * Caveats on high order pages: page->_count will only be set
 193          * -1 on the head page; SLUB/SLQB do the same for PG_slab;
 194          * SLOB won't set PG_slab at all on compound pages.
 195          */
 196         if (PageBuddy(page))
 197                 u |= 1 << KPF_BUDDY;
 198
 199         u |= kpf_copy_bit(k, KPF_LOCKED,        PG_locked);
 200
 201         u |= kpf_copy_bit(k, KPF_SLAB,          PG_slab);
 202
 203         u |= kpf_copy_bit(k, KPF_ERROR,         PG_error);
 204         u |= kpf_copy_bit(k, KPF_DIRTY,         PG_dirty);
 205         u |= kpf_copy_bit(k, KPF_UPTODATE,      PG_uptodate);
 206         u |= kpf_copy_bit(k, KPF_WRITEBACK,     PG_writeback);
 207
 208         u |= kpf_copy_bit(k, KPF_LRU,           PG_lru);
 209         u |= kpf_copy_bit(k, KPF_REFERENCED,    PG_referenced);
 210         u |= kpf_copy_bit(k, KPF_ACTIVE,        PG_active);
 211         u |= kpf_copy_bit(k, KPF_RECLAIM,       PG_reclaim);
 212
 213         u |= kpf_copy_bit(k, KPF_SWAPCACHE,     PG_swapcache);
 214         u |= kpf_copy_bit(k, KPF_SWAPBACKED,    PG_swapbacked);
 215
 216         u |= kpf_copy_bit(k, KPF_UNEVICTABLE,   PG_unevictable);
 217         u |= kpf_copy_bit(k, KPF_MLOCKED,       PG_mlocked);
 218
 219 #ifdef CONFIG_MEMORY_FAILURE
 220         u |= kpf_copy_bit(k, KPF_HWPOISON,      PG_hwpoison);
 221 #endif
 222
 223 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
 224         u |= kpf_copy_bit(k, KPF_UNCACHED,      PG_uncached);
 225 #endif
 226
 227         u |= kpf_copy_bit(k, KPF_RESERVED,      PG_reserved);
 228         u |= kpf_copy_bit(k, KPF_MAPPEDTODISK,  PG_mappedtodisk);
 229         u |= kpf_copy_bit(k, KPF_PRIVATE,       PG_private);
 230         u |= kpf_copy_bit(k, KPF_PRIVATE_2,     PG_private_2);
 231         u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
 232         u |= kpf_copy_bit(k, KPF_ARCH,          PG_arch_1);
 233
 234         return u;
 235 };
 236
 237 static ssize_t kpageflags_read(struct file *file, char __user *buf,
 238                              size_t count, loff_t *ppos)
 239 {
 240         u64 __user *out = (u64 __user *)buf;
 241         struct page *ppage;
 242         unsigned long src = *ppos;
 243         unsigned long pfn;
 244         unsigned long max_pfn_kpmsize = max_pfn * KPMSIZE;
 245         ssize_t ret = 0;
 246
 247         pfn = src / KPMSIZE;
 248         if(src != max_pfn_kpmsize){
 249             count = min_t(unsigned long, count, max_pfn_kpmsize - src);
 250         }
 251
 252         if (src & KPMMASK || count & KPMMASK)
 253                 return -EINVAL;
 254
 255         while (count > 0) {
 256                 if (pfn_valid(pfn))
 257                         ppage = pfn_to_page(pfn);
 258                 else
 259                         ppage = NULL;
 260
 261                 if (put_user(stable_page_flags(ppage), out)) {
 262                         ret = -EFAULT;
 263                         break;
 264                 }
 265
 266                 pfn++;
 267                 out++;
 268                 count -= KPMSIZE;
 269         }
 270
 271         *ppos += (char __user *)out - buf;
 272         if (!ret)
 273                 ret = (char __user *)out - buf;
 274         return ret;
 275 }
 276
 277 static const struct file_operations proc_kpageflags_operations = {
 278         .llseek = mem_lseek,
 279         .read = kpageflags_read,
 280 };
 281
 282 static int __init proc_page_init(void)
 283 {
 284         proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
 285 #ifdef CONFIG_SWAP
 286         proc_create("kpageswapn", S_IRUSR, NULL, &proc_kpageswapn_operations);
 287 #endif // CONFIG_SWAP
 288         proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
 289         return 0;
 290 }
 291 module_init(proc_page_init);