arch/s390/mm/pageattr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright IBM Corp. 2011
   4  * Author(s): Jan Glauber <[email protected]>
   5  */
   6 #include <linux/hugetlb.h>
   7 #include <linux/proc_fs.h>
   8 #include <linux/vmalloc.h>
   9 #include <linux/mm.h>
  10 #include <asm/cacheflush.h>
  11 #include <asm/facility.h>
  12 #include <asm/pgalloc.h>
  13 #include <asm/kfence.h>
  14 #include <asm/page.h>
  15 #include <asm/asm.h>
  16 #include <asm/set_memory.h>
  17
  18 static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
  19 {
  20         asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],1,0"
  21                      : [addr] "+a" (addr) : [skey] "d" (skey));
  22         return addr;
  23 }
  24
  25 void __storage_key_init_range(unsigned long start, unsigned long end)
  26 {
  27         unsigned long boundary, size;
  28
  29         while (start < end) {
  30                 if (MACHINE_HAS_EDAT1) {
  31                         /* set storage keys for a 1MB frame */
  32                         size = 1UL << 20;
  33                         boundary = (start + size) & ~(size - 1);
  34                         if (boundary <= end) {
  35                                 do {
  36                                         start = sske_frame(start, PAGE_DEFAULT_KEY);
  37                                 } while (start < boundary);
  38                                 continue;
  39                         }
  40                 }
  41                 page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
  42                 start += PAGE_SIZE;
  43         }
  44 }
  45
  46 #ifdef CONFIG_PROC_FS
  47 atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
  48
  49 void arch_report_meminfo(struct seq_file *m)
  50 {
  51         seq_printf(m, "DirectMap4k:    %8lu kB\n",
  52                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
  53         seq_printf(m, "DirectMap1M:    %8lu kB\n",
  54                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
  55         seq_printf(m, "DirectMap2G:    %8lu kB\n",
  56                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
  57 }
  58 #endif /* CONFIG_PROC_FS */
  59
  60 static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
  61                     unsigned long dtt)
  62 {
  63         unsigned long *table, mask;
  64
  65         mask = 0;
  66         if (MACHINE_HAS_EDAT2) {
  67                 switch (dtt) {
  68                 case CRDTE_DTT_REGION3:
  69                         mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
  70                         break;
  71                 case CRDTE_DTT_SEGMENT:
  72                         mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
  73                         break;
  74                 case CRDTE_DTT_PAGE:
  75                         mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
  76                         break;
  77                 }
  78                 table = (unsigned long *)((unsigned long)old & mask);
  79                 crdte(*old, new, table, dtt, addr, get_lowcore()->kernel_asce.val);
  80         } else if (MACHINE_HAS_IDTE) {
  81                 cspg(old, *old, new);
  82         } else {
  83                 csp((unsigned int *)old + 1, *old, new);
  84         }
  85 }
  86
  87 static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
  88                           unsigned long flags)
  89 {
  90         pte_t *ptep, new;
  91
  92         if (flags == SET_MEMORY_4K)
  93                 return 0;
  94         ptep = pte_offset_kernel(pmdp, addr);
  95         do {
  96                 new = *ptep;
  97                 if (pte_none(new))
  98                         return -EINVAL;
  99                 if (flags & SET_MEMORY_RO)
 100                         new = pte_wrprotect(new);
 101                 else if (flags & SET_MEMORY_RW)
 102                         new = pte_mkwrite_novma(pte_mkdirty(new));
 103                 if (flags & SET_MEMORY_NX)
 104                         new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 105                 else if (flags & SET_MEMORY_X)
 106                         new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 107                 if (flags & SET_MEMORY_INV) {
 108                         new = set_pte_bit(new, __pgprot(_PAGE_INVALID));
 109                 } else if (flags & SET_MEMORY_DEF) {
 110                         new = __pte(pte_val(new) & PAGE_MASK);
 111                         new = set_pte_bit(new, PAGE_KERNEL);
 112                         if (!MACHINE_HAS_NX)
 113                                 new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 114                 }
 115                 pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
 116                 ptep++;
 117                 addr += PAGE_SIZE;
 118                 cond_resched();
 119         } while (addr < end);
 120         return 0;
 121 }
 122
 123 static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
 124 {
 125         unsigned long pte_addr, prot;
 126         pte_t *pt_dir, *ptep;
 127         pmd_t new;
 128         int i, ro, nx;
 129
 130         pt_dir = vmem_pte_alloc();
 131         if (!pt_dir)
 132                 return -ENOMEM;
 133         pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
 134         ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
 135         nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
 136         prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
 137         if (!nx)
 138                 prot &= ~_PAGE_NOEXEC;
 139         ptep = pt_dir;
 140         for (i = 0; i < PTRS_PER_PTE; i++) {
 141                 set_pte(ptep, __pte(pte_addr | prot));
 142                 pte_addr += PAGE_SIZE;
 143                 ptep++;
 144         }
 145         new = __pmd(__pa(pt_dir) | _SEGMENT_ENTRY);
 146         pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
 147         update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
 148         update_page_count(PG_DIRECT_MAP_1M, -1);
 149         return 0;
 150 }
 151
 152 static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
 153                             unsigned long flags)
 154 {
 155         pmd_t new = *pmdp;
 156
 157         if (flags & SET_MEMORY_RO)
 158                 new = pmd_wrprotect(new);
 159         else if (flags & SET_MEMORY_RW)
 160                 new = pmd_mkwrite_novma(pmd_mkdirty(new));
 161         if (flags & SET_MEMORY_NX)
 162                 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 163         else if (flags & SET_MEMORY_X)
 164                 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 165         if (flags & SET_MEMORY_INV) {
 166                 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
 167         } else if (flags & SET_MEMORY_DEF) {
 168                 new = __pmd(pmd_val(new) & PMD_MASK);
 169                 new = set_pmd_bit(new, SEGMENT_KERNEL);
 170                 if (!MACHINE_HAS_NX)
 171                         new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 172         }
 173         pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
 174 }
 175
 176 static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
 177                           unsigned long flags)
 178 {
 179         unsigned long next;
 180         int need_split;
 181         pmd_t *pmdp;
 182         int rc = 0;
 183
 184         pmdp = pmd_offset(pudp, addr);
 185         do {
 186                 if (pmd_none(*pmdp))
 187                         return -EINVAL;
 188                 next = pmd_addr_end(addr, end);
 189                 if (pmd_leaf(*pmdp)) {
 190                         need_split  = !!(flags & SET_MEMORY_4K);
 191                         need_split |= !!(addr & ~PMD_MASK);
 192                         need_split |= !!(addr + PMD_SIZE > next);
 193                         if (need_split) {
 194                                 rc = split_pmd_page(pmdp, addr);
 195                                 if (rc)
 196                                         return rc;
 197                                 continue;
 198                         }
 199                         modify_pmd_page(pmdp, addr, flags);
 200                 } else {
 201                         rc = walk_pte_level(pmdp, addr, next, flags);
 202                         if (rc)
 203                                 return rc;
 204                 }
 205                 pmdp++;
 206                 addr = next;
 207                 cond_resched();
 208         } while (addr < end);
 209         return rc;
 210 }
 211
 212 static int split_pud_page(pud_t *pudp, unsigned long addr)
 213 {
 214         unsigned long pmd_addr, prot;
 215         pmd_t *pm_dir, *pmdp;
 216         pud_t new;
 217         int i, ro, nx;
 218
 219         pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
 220         if (!pm_dir)
 221                 return -ENOMEM;
 222         pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
 223         ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
 224         nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
 225         prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
 226         if (!nx)
 227                 prot &= ~_SEGMENT_ENTRY_NOEXEC;
 228         pmdp = pm_dir;
 229         for (i = 0; i < PTRS_PER_PMD; i++) {
 230                 set_pmd(pmdp, __pmd(pmd_addr | prot));
 231                 pmd_addr += PMD_SIZE;
 232                 pmdp++;
 233         }
 234         new = __pud(__pa(pm_dir) | _REGION3_ENTRY);
 235         pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
 236         update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
 237         update_page_count(PG_DIRECT_MAP_2G, -1);
 238         return 0;
 239 }
 240
 241 static void modify_pud_page(pud_t *pudp, unsigned long addr,
 242                             unsigned long flags)
 243 {
 244         pud_t new = *pudp;
 245
 246         if (flags & SET_MEMORY_RO)
 247                 new = pud_wrprotect(new);
 248         else if (flags & SET_MEMORY_RW)
 249                 new = pud_mkwrite(pud_mkdirty(new));
 250         if (flags & SET_MEMORY_NX)
 251                 new = set_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
 252         else if (flags & SET_MEMORY_X)
 253                 new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
 254         if (flags & SET_MEMORY_INV) {
 255                 new = set_pud_bit(new, __pgprot(_REGION_ENTRY_INVALID));
 256         } else if (flags & SET_MEMORY_DEF) {
 257                 new = __pud(pud_val(new) & PUD_MASK);
 258                 new = set_pud_bit(new, REGION3_KERNEL);
 259                 if (!MACHINE_HAS_NX)
 260                         new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
 261         }
 262         pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
 263 }
 264
 265 static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
 266                           unsigned long flags)
 267 {
 268         unsigned long next;
 269         int need_split;
 270         pud_t *pudp;
 271         int rc = 0;
 272
 273         pudp = pud_offset(p4d, addr);
 274         do {
 275                 if (pud_none(*pudp))
 276                         return -EINVAL;
 277                 next = pud_addr_end(addr, end);
 278                 if (pud_leaf(*pudp)) {
 279                         need_split  = !!(flags & SET_MEMORY_4K);
 280                         need_split |= !!(addr & ~PUD_MASK);
 281                         need_split |= !!(addr + PUD_SIZE > next);
 282                         if (need_split) {
 283                                 rc = split_pud_page(pudp, addr);
 284                                 if (rc)
 285                                         break;
 286                                 continue;
 287                         }
 288                         modify_pud_page(pudp, addr, flags);
 289                 } else {
 290                         rc = walk_pmd_level(pudp, addr, next, flags);
 291                 }
 292                 pudp++;
 293                 addr = next;
 294                 cond_resched();
 295         } while (addr < end && !rc);
 296         return rc;
 297 }
 298
 299 static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
 300                           unsigned long flags)
 301 {
 302         unsigned long next;
 303         p4d_t *p4dp;
 304         int rc = 0;
 305
 306         p4dp = p4d_offset(pgd, addr);
 307         do {
 308                 if (p4d_none(*p4dp))
 309                         return -EINVAL;
 310                 next = p4d_addr_end(addr, end);
 311                 rc = walk_pud_level(p4dp, addr, next, flags);
 312                 p4dp++;
 313                 addr = next;
 314                 cond_resched();
 315         } while (addr < end && !rc);
 316         return rc;
 317 }
 318
 319 DEFINE_MUTEX(cpa_mutex);
 320
 321 static int change_page_attr(unsigned long addr, unsigned long end,
 322                             unsigned long flags)
 323 {
 324         unsigned long next;
 325         int rc = -EINVAL;
 326         pgd_t *pgdp;
 327
 328         pgdp = pgd_offset_k(addr);
 329         do {
 330                 if (pgd_none(*pgdp))
 331                         break;
 332                 next = pgd_addr_end(addr, end);
 333                 rc = walk_p4d_level(pgdp, addr, next, flags);
 334                 if (rc)
 335                         break;
 336                 cond_resched();
 337         } while (pgdp++, addr = next, addr < end && !rc);
 338         return rc;
 339 }
 340
 341 static int change_page_attr_alias(unsigned long addr, unsigned long end,
 342                                   unsigned long flags)
 343 {
 344         unsigned long alias, offset, va_start, va_end;
 345         struct vm_struct *area;
 346         int rc = 0;
 347
 348         /*
 349          * Changes to read-only permissions on kernel VA mappings are also
 350          * applied to the kernel direct mapping. Execute permissions are
 351          * intentionally not transferred to keep all allocated pages within
 352          * the direct mapping non-executable.
 353          */
 354         flags &= SET_MEMORY_RO | SET_MEMORY_RW;
 355         if (!flags)
 356                 return 0;
 357         area = NULL;
 358         while (addr < end) {
 359                 if (!area)
 360                         area = find_vm_area((void *)addr);
 361                 if (!area || !(area->flags & VM_ALLOC))
 362                         return 0;
 363                 va_start = (unsigned long)area->addr;
 364                 va_end = va_start + area->nr_pages * PAGE_SIZE;
 365                 offset = (addr - va_start) >> PAGE_SHIFT;
 366                 alias = (unsigned long)page_address(area->pages[offset]);
 367                 rc = change_page_attr(alias, alias + PAGE_SIZE, flags);
 368                 if (rc)
 369                         break;
 370                 addr += PAGE_SIZE;
 371                 if (addr >= va_end)
 372                         area = NULL;
 373         }
 374         return rc;
 375 }
 376
 377 int __set_memory(unsigned long addr, unsigned long numpages, unsigned long flags)
 378 {
 379         unsigned long end;
 380         int rc;
 381
 382         if (!MACHINE_HAS_NX)
 383                 flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
 384         if (!flags)
 385                 return 0;
 386         if (!numpages)
 387                 return 0;
 388         addr &= PAGE_MASK;
 389         end = addr + numpages * PAGE_SIZE;
 390         mutex_lock(&cpa_mutex);
 391         rc = change_page_attr(addr, end, flags);
 392         if (rc)
 393                 goto out;
 394         rc = change_page_attr_alias(addr, end, flags);
 395 out:
 396         mutex_unlock(&cpa_mutex);
 397         return rc;
 398 }
 399
 400 int set_direct_map_invalid_noflush(struct page *page)
 401 {
 402         return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_INV);
 403 }
 404
 405 int set_direct_map_default_noflush(struct page *page)
 406 {
 407         return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_DEF);
 408 }
 409
 410 bool kernel_page_present(struct page *page)
 411 {
 412         unsigned long addr;
 413         unsigned int cc;
 414
 415         addr = (unsigned long)page_address(page);
 416         asm volatile(
 417                 "       lra     %[addr],0(%[addr])\n"
 418                 CC_IPM(cc)
 419                 : CC_OUT(cc, cc), [addr] "+a" (addr)
 420                 :
 421                 : CC_CLOBBER);
 422         return CC_TRANSFORM(cc) == 0;
 423 }
 424
 425 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
 426
 427 static void ipte_range(pte_t *pte, unsigned long address, int nr)
 428 {
 429         int i;
 430
 431         if (test_facility(13)) {
 432                 __ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
 433                 return;
 434         }
 435         for (i = 0; i < nr; i++) {
 436                 __ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
 437                 address += PAGE_SIZE;
 438                 pte++;
 439         }
 440 }
 441
 442 void __kernel_map_pages(struct page *page, int numpages, int enable)
 443 {
 444         unsigned long address;
 445         pte_t *ptep, pte;
 446         int nr, i, j;
 447
 448         for (i = 0; i < numpages;) {
 449                 address = (unsigned long)page_to_virt(page + i);
 450                 ptep = virt_to_kpte(address);
 451                 nr = (unsigned long)ptep >> ilog2(sizeof(long));
 452                 nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
 453                 nr = min(numpages - i, nr);
 454                 if (enable) {
 455                         for (j = 0; j < nr; j++) {
 456                                 pte = clear_pte_bit(*ptep, __pgprot(_PAGE_INVALID));
 457                                 set_pte(ptep, pte);
 458                                 address += PAGE_SIZE;
 459                                 ptep++;
 460                         }
 461                 } else {
 462                         ipte_range(ptep, address, nr);
 463                 }
 464                 i += nr;
 465         }
 466 }
 467
 468 #endif /* CONFIG_DEBUG_PAGEALLOC */