1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/memblock.h> 3 #include <linux/compiler.h> 4 #include <linux/fs.h> 5 #include <linux/init.h> 6 #include <linux/ksm.h> 7 #include <linux/mm.h> 8 #include <linux/mmzone.h> 9 #include <linux/huge_mm.h> 10 #include <linux/proc_fs.h> 11 #include <linux/seq_file.h> 12 #include <linux/hugetlb.h> 13 #include <linux/memremap.h> 14 #include <linux/memcontrol.h> 15 #include <linux/mmu_notifier.h> 16 #include <linux/page_idle.h> 17 #include <linux/kernel-page-flags.h> 18 #include <linux/uaccess.h> 19 #include "internal.h" 20 21 #define KPMSIZE sizeof(u64) 22 #define KPMMASK (KPMSIZE - 1) 23 #define KPMBITS (KPMSIZE * BITS_PER_BYTE) 24 25 static inline unsigned long get_max_dump_pfn(void) 26 { 27 #ifdef CONFIG_SPARSEMEM 28 /* 29 * The memmap of early sections is completely populated and marked 30 * online even if max_pfn does not fall on a section boundary - 31 * pfn_to_online_page() will succeed on all pages. Allow inspecting 32 * these memmaps. 33 */ 34 return round_up(max_pfn, PAGES_PER_SECTION); 35 #else 36 return max_pfn; 37 #endif 38 } 39 40 /* /proc/kpagecount - an array exposing page counts 41 * 42 * Each entry is a u64 representing the corresponding 43 * physical page count. 44 */ 45 static ssize_t kpagecount_read(struct file *file, char __user *buf, 46 size_t count, loff_t *ppos) 47 { 48 const unsigned long max_dump_pfn = get_max_dump_pfn(); 49 u64 __user *out = (u64 __user *)buf; 50 struct page *ppage; 51 unsigned long src = *ppos; 52 unsigned long pfn; 53 ssize_t ret = 0; 54 u64 pcount; 55 56 pfn = src / KPMSIZE; 57 if (src & KPMMASK || count & KPMMASK) 58 return -EINVAL; 59 if (src >= max_dump_pfn * KPMSIZE) 60 return 0; 61 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src); 62 63 while (count > 0) { 64 /* 65 * TODO: ZONE_DEVICE support requires to identify 66 * memmaps that were actually initialized. 67 */ 68 ppage = pfn_to_online_page(pfn); 69 70 if (!ppage) 71 pcount = 0; 72 else 73 pcount = page_mapcount(ppage); 74 75 if (put_user(pcount, out)) { 76 ret = -EFAULT; 77 break; 78 } 79 80 pfn++; 81 out++; 82 count -= KPMSIZE; 83 84 cond_resched(); 85 } 86 87 *ppos += (char __user *)out - buf; 88 if (!ret) 89 ret = (char __user *)out - buf; 90 return ret; 91 } 92 93 static const struct proc_ops kpagecount_proc_ops = { 94 .proc_flags = PROC_ENTRY_PERMANENT, 95 .proc_lseek = mem_lseek, 96 .proc_read = kpagecount_read, 97 }; 98 99 /* /proc/kpageflags - an array exposing page flags 100 * 101 * Each entry is a u64 representing the corresponding 102 * physical page flags. 103 */ 104 105 static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit) 106 { 107 return ((kflags >> kbit) & 1) << ubit; 108 } 109 110 u64 stable_page_flags(struct page *page) 111 { 112 u64 k; 113 u64 u; 114 115 /* 116 * pseudo flag: KPF_NOPAGE 117 * it differentiates a memory hole from a page with no flags 118 */ 119 if (!page) 120 return 1 << KPF_NOPAGE; 121 122 k = page->flags; 123 u = 0; 124 125 /* 126 * pseudo flags for the well known (anonymous) memory mapped pages 127 */ 128 if (page_mapped(page)) 129 u |= 1 << KPF_MMAP; 130 if (PageAnon(page)) 131 u |= 1 << KPF_ANON; 132 if (PageKsm(page)) 133 u |= 1 << KPF_KSM; 134 135 /* 136 * compound pages: export both head/tail info 137 * they together define a compound page's start/end pos and order 138 */ 139 if (PageHead(page)) 140 u |= 1 << KPF_COMPOUND_HEAD; 141 if (PageTail(page)) 142 u |= 1 << KPF_COMPOUND_TAIL; 143 if (PageHuge(page)) 144 u |= 1 << KPF_HUGE; 145 /* 146 * PageTransCompound can be true for non-huge compound pages (slab 147 * pages or pages allocated by drivers with __GFP_COMP) because it 148 * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon 149 * to make sure a given page is a thp, not a non-huge compound page. 150 */ 151 else if (PageTransCompound(page)) { 152 struct page *head = compound_head(page); 153 154 if (PageLRU(head) || PageAnon(head)) 155 u |= 1 << KPF_THP; 156 else if (is_huge_zero_page(head)) { 157 u |= 1 << KPF_ZERO_PAGE; 158 u |= 1 << KPF_THP; 159 } 160 } else if (is_zero_pfn(page_to_pfn(page))) 161 u |= 1 << KPF_ZERO_PAGE; 162 163 164 /* 165 * Caveats on high order pages: PG_buddy and PG_slab will only be set 166 * on the head page. 167 */ 168 if (PageBuddy(page)) 169 u |= 1 << KPF_BUDDY; 170 else if (page_count(page) == 0 && is_free_buddy_page(page)) 171 u |= 1 << KPF_BUDDY; 172 173 if (PageOffline(page)) 174 u |= 1 << KPF_OFFLINE; 175 if (PageTable(page)) 176 u |= 1 << KPF_PGTABLE; 177 178 if (page_is_idle(page)) 179 u |= 1 << KPF_IDLE; 180 181 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked); 182 183 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab); 184 if (PageTail(page) && PageSlab(page)) 185 u |= 1 << KPF_SLAB; 186 187 u |= kpf_copy_bit(k, KPF_ERROR, PG_error); 188 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); 189 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate); 190 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback); 191 192 u |= kpf_copy_bit(k, KPF_LRU, PG_lru); 193 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced); 194 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active); 195 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim); 196 197 if (PageSwapCache(page)) 198 u |= 1 << KPF_SWAPCACHE; 199 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked); 200 201 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable); 202 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); 203 204 #ifdef CONFIG_MEMORY_FAILURE 205 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); 206 #endif 207 208 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 209 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached); 210 #endif 211 212 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); 213 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); 214 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); 215 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); 216 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); 217 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); 218 #ifdef CONFIG_ARCH_USES_PG_ARCH_X 219 u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); 220 u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3); 221 #endif 222 223 return u; 224 }; 225 226 static ssize_t kpageflags_read(struct file *file, char __user *buf, 227 size_t count, loff_t *ppos) 228 { 229 const unsigned long max_dump_pfn = get_max_dump_pfn(); 230 u64 __user *out = (u64 __user *)buf; 231 struct page *ppage; 232 unsigned long src = *ppos; 233 unsigned long pfn; 234 ssize_t ret = 0; 235 236 pfn = src / KPMSIZE; 237 if (src & KPMMASK || count & KPMMASK) 238 return -EINVAL; 239 if (src >= max_dump_pfn * KPMSIZE) 240 return 0; 241 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src); 242 243 while (count > 0) { 244 /* 245 * TODO: ZONE_DEVICE support requires to identify 246 * memmaps that were actually initialized. 247 */ 248 ppage = pfn_to_online_page(pfn); 249 250 if (put_user(stable_page_flags(ppage), out)) { 251 ret = -EFAULT; 252 break; 253 } 254 255 pfn++; 256 out++; 257 count -= KPMSIZE; 258 259 cond_resched(); 260 } 261 262 *ppos += (char __user *)out - buf; 263 if (!ret) 264 ret = (char __user *)out - buf; 265 return ret; 266 } 267 268 static const struct proc_ops kpageflags_proc_ops = { 269 .proc_flags = PROC_ENTRY_PERMANENT, 270 .proc_lseek = mem_lseek, 271 .proc_read = kpageflags_read, 272 }; 273 274 #ifdef CONFIG_MEMCG 275 static ssize_t kpagecgroup_read(struct file *file, char __user *buf, 276 size_t count, loff_t *ppos) 277 { 278 const unsigned long max_dump_pfn = get_max_dump_pfn(); 279 u64 __user *out = (u64 __user *)buf; 280 struct page *ppage; 281 unsigned long src = *ppos; 282 unsigned long pfn; 283 ssize_t ret = 0; 284 u64 ino; 285 286 pfn = src / KPMSIZE; 287 if (src & KPMMASK || count & KPMMASK) 288 return -EINVAL; 289 if (src >= max_dump_pfn * KPMSIZE) 290 return 0; 291 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src); 292 293 while (count > 0) { 294 /* 295 * TODO: ZONE_DEVICE support requires to identify 296 * memmaps that were actually initialized. 297 */ 298 ppage = pfn_to_online_page(pfn); 299 300 if (ppage) 301 ino = page_cgroup_ino(ppage); 302 else 303 ino = 0; 304 305 if (put_user(ino, out)) { 306 ret = -EFAULT; 307 break; 308 } 309 310 pfn++; 311 out++; 312 count -= KPMSIZE; 313 314 cond_resched(); 315 } 316 317 *ppos += (char __user *)out - buf; 318 if (!ret) 319 ret = (char __user *)out - buf; 320 return ret; 321 } 322 323 static const struct proc_ops kpagecgroup_proc_ops = { 324 .proc_flags = PROC_ENTRY_PERMANENT, 325 .proc_lseek = mem_lseek, 326 .proc_read = kpagecgroup_read, 327 }; 328 #endif /* CONFIG_MEMCG */ 329 330 static int __init proc_page_init(void) 331 { 332 proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops); 333 proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops); 334 #ifdef CONFIG_MEMCG 335 proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops); 336 #endif 337 return 0; 338 } 339 fs_initcall(proc_page_init); 340