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 <asm/uaccess.h> 12 #include "internal.h" 13 14 #define KPMSIZE sizeof(u64) 15 #define KPMMASK (KPMSIZE - 1) 16 17 /* /proc/kpagecount - an array exposing page counts 18 * 19 * Each entry is a u64 representing the corresponding 20 * physical page count. 21 */ 22 static ssize_t kpagecount_read(struct file *file, char __user *buf, 23 size_t count, loff_t *ppos) 24 { 25 u64 __user *out = (u64 __user *)buf; 26 struct page *ppage; 27 unsigned long src = *ppos; 28 unsigned long pfn; 29 ssize_t ret = 0; 30 u64 pcount; 31 32 pfn = src / KPMSIZE; 33 count = min_t(size_t, count, (max_pfn * KPMSIZE) - src); 34 if (src & KPMMASK || count & KPMMASK) 35 return -EINVAL; 36 37 while (count > 0) { 38 if (pfn_valid(pfn)) 39 ppage = pfn_to_page(pfn); 40 else 41 ppage = NULL; 42 if (!ppage) 43 pcount = 0; 44 else 45 pcount = page_mapcount(ppage); 46 47 if (put_user(pcount, out)) { 48 ret = -EFAULT; 49 break; 50 } 51 52 pfn++; 53 out++; 54 count -= KPMSIZE; 55 } 56 57 *ppos += (char __user *)out - buf; 58 if (!ret) 59 ret = (char __user *)out - buf; 60 return ret; 61 } 62 63 static const struct file_operations proc_kpagecount_operations = { 64 .llseek = mem_lseek, 65 .read = kpagecount_read, 66 }; 67 68 /* /proc/kpageflags - an array exposing page flags 69 * 70 * Each entry is a u64 representing the corresponding 71 * physical page flags. 72 */ 73 74 /* These macros are used to decouple internal flags from exported ones */ 75 76 #define KPF_LOCKED 0 77 #define KPF_ERROR 1 78 #define KPF_REFERENCED 2 79 #define KPF_UPTODATE 3 80 #define KPF_DIRTY 4 81 #define KPF_LRU 5 82 #define KPF_ACTIVE 6 83 #define KPF_SLAB 7 84 #define KPF_WRITEBACK 8 85 #define KPF_RECLAIM 9 86 #define KPF_BUDDY 10 87 88 /* 11-20: new additions in 2.6.31 */ 89 #define KPF_MMAP 11 90 #define KPF_ANON 12 91 #define KPF_SWAPCACHE 13 92 #define KPF_SWAPBACKED 14 93 #define KPF_COMPOUND_HEAD 15 94 #define KPF_COMPOUND_TAIL 16 95 #define KPF_HUGE 17 96 #define KPF_UNEVICTABLE 18 97 #define KPF_HWPOISON 19 98 #define KPF_NOPAGE 20 99 100 #define KPF_KSM 21 101 102 /* kernel hacking assistances 103 * WARNING: subject to change, never rely on them! 104 */ 105 #define KPF_RESERVED 32 106 #define KPF_MLOCKED 33 107 #define KPF_MAPPEDTODISK 34 108 #define KPF_PRIVATE 35 109 #define KPF_PRIVATE_2 36 110 #define KPF_OWNER_PRIVATE 37 111 #define KPF_ARCH 38 112 #define KPF_UNCACHED 39 113 114 static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit) 115 { 116 return ((kflags >> kbit) & 1) << ubit; 117 } 118 119 static u64 get_uflags(struct page *page) 120 { 121 u64 k; 122 u64 u; 123 124 /* 125 * pseudo flag: KPF_NOPAGE 126 * it differentiates a memory hole from a page with no flags 127 */ 128 if (!page) 129 return 1 << KPF_NOPAGE; 130 131 k = page->flags; 132 u = 0; 133 134 /* 135 * pseudo flags for the well known (anonymous) memory mapped pages 136 * 137 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the 138 * simple test in page_mapped() is not enough. 139 */ 140 if (!PageSlab(page) && page_mapped(page)) 141 u |= 1 << KPF_MMAP; 142 if (PageAnon(page)) 143 u |= 1 << KPF_ANON; 144 if (PageKsm(page)) 145 u |= 1 << KPF_KSM; 146 147 /* 148 * compound pages: export both head/tail info 149 * they together define a compound page's start/end pos and order 150 */ 151 if (PageHead(page)) 152 u |= 1 << KPF_COMPOUND_HEAD; 153 if (PageTail(page)) 154 u |= 1 << KPF_COMPOUND_TAIL; 155 if (PageHuge(page)) 156 u |= 1 << KPF_HUGE; 157 158 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked); 159 160 /* 161 * Caveats on high order pages: 162 * PG_buddy will only be set on the head page; SLUB/SLQB do the same 163 * for PG_slab; SLOB won't set PG_slab at all on compound pages. 164 */ 165 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab); 166 u |= kpf_copy_bit(k, KPF_BUDDY, PG_buddy); 167 168 u |= kpf_copy_bit(k, KPF_ERROR, PG_error); 169 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); 170 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate); 171 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback); 172 173 u |= kpf_copy_bit(k, KPF_LRU, PG_lru); 174 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced); 175 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active); 176 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim); 177 178 u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache); 179 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked); 180 181 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable); 182 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); 183 184 #ifdef CONFIG_MEMORY_FAILURE 185 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); 186 #endif 187 188 #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR 189 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached); 190 #endif 191 192 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); 193 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); 194 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); 195 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); 196 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); 197 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); 198 199 return u; 200 }; 201 202 static ssize_t kpageflags_read(struct file *file, char __user *buf, 203 size_t count, loff_t *ppos) 204 { 205 u64 __user *out = (u64 __user *)buf; 206 struct page *ppage; 207 unsigned long src = *ppos; 208 unsigned long pfn; 209 ssize_t ret = 0; 210 211 pfn = src / KPMSIZE; 212 count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src); 213 if (src & KPMMASK || count & KPMMASK) 214 return -EINVAL; 215 216 while (count > 0) { 217 if (pfn_valid(pfn)) 218 ppage = pfn_to_page(pfn); 219 else 220 ppage = NULL; 221 222 if (put_user(get_uflags(ppage), out)) { 223 ret = -EFAULT; 224 break; 225 } 226 227 pfn++; 228 out++; 229 count -= KPMSIZE; 230 } 231 232 *ppos += (char __user *)out - buf; 233 if (!ret) 234 ret = (char __user *)out - buf; 235 return ret; 236 } 237 238 static const struct file_operations proc_kpageflags_operations = { 239 .llseek = mem_lseek, 240 .read = kpageflags_read, 241 }; 242 243 static int __init proc_page_init(void) 244 { 245 proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations); 246 proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations); 247 return 0; 248 } 249 module_init(proc_page_init); 250