arch/s390/mm/pageattr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright IBM Corp. 2011
   4  * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
   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/set_memory.h>
  16
  17 static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
  18 {
  19         asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],1,0"
  20                      : [addr] "+a" (addr) : [skey] "d" (skey));
  21         return addr;
  22 }
  23
  24 void __storage_key_init_range(unsigned long start, unsigned long end)
  25 {
  26         unsigned long boundary, size;
  27
  28         while (start < end) {
  29                 if (MACHINE_HAS_EDAT1) {
  30                         /* set storage keys for a 1MB frame */
  31                         size = 1UL << 20;
  32                         boundary = (start + size) & ~(size - 1);
  33                         if (boundary <= end) {
  34                                 do {
  35                                         start = sske_frame(start, PAGE_DEFAULT_KEY);
  36                                 } while (start < boundary);
  37                                 continue;
  38                         }
  39                 }
  40                 page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
  41                 start += PAGE_SIZE;
  42         }
  43 }
  44
  45 #ifdef CONFIG_PROC_FS
  46 atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
  47
  48 void arch_report_meminfo(struct seq_file *m)
  49 {
  50         seq_printf(m, "DirectMap4k:    %8lu kB\n",
  51                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
  52         seq_printf(m, "DirectMap1M:    %8lu kB\n",
  53                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
  54         seq_printf(m, "DirectMap2G:    %8lu kB\n",
  55                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
  56 }
  57 #endif /* CONFIG_PROC_FS */
  58
  59 static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
  60                     unsigned long dtt)
  61 {
  62         unsigned long *table, mask;
  63
  64         mask = 0;
  65         if (MACHINE_HAS_EDAT2) {
  66                 switch (dtt) {
  67                 case CRDTE_DTT_REGION3:
  68                         mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
  69                         break;
  70                 case CRDTE_DTT_SEGMENT:
  71                         mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
  72                         break;
  73                 case CRDTE_DTT_PAGE:
  74                         mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
  75                         break;
  76                 }
  77                 table = (unsigned long *)((unsigned long)old & mask);
  78                 crdte(*old, new, table, dtt, addr, S390_lowcore.kernel_asce);
  79         } else if (MACHINE_HAS_IDTE) {
  80                 cspg(old, *old, new);
  81         } else {
  82                 csp((unsigned int *)old + 1, *old, new);
  83         }
  84 }
  85
  86 static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
  87                           unsigned long flags)
  88 {
  89         pte_t *ptep, new;
  90
  91         if (flags == SET_MEMORY_4K)
  92                 return 0;
  93         ptep = pte_offset_kernel(pmdp, addr);
  94         do {
  95                 new = *ptep;
  96                 if (pte_none(new))
  97                         return -EINVAL;
  98                 if (flags & SET_MEMORY_RO)
  99                         new = pte_wrprotect(new);
 100                 else if (flags & SET_MEMORY_RW)
 101                         new = pte_mkwrite_novma(pte_mkdirty(new));
 102                 if (flags & SET_MEMORY_NX)
 103                         new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 104                 else if (flags & SET_MEMORY_X)
 105                         new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 106                 if (flags & SET_MEMORY_INV) {
 107                         new = set_pte_bit(new, __pgprot(_PAGE_INVALID));
 108                 } else if (flags & SET_MEMORY_DEF) {
 109                         new = __pte(pte_val(new) & PAGE_MASK);
 110                         new = set_pte_bit(new, PAGE_KERNEL);
 111                         if (!MACHINE_HAS_NX)
 112                                 new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 113                 }
 114                 pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
 115                 ptep++;
 116                 addr += PAGE_SIZE;
 117                 cond_resched();
 118         } while (addr < end);
 119         return 0;
 120 }
 121
 122 static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
 123 {
 124         unsigned long pte_addr, prot;
 125         pte_t *pt_dir, *ptep;
 126         pmd_t new;
 127         int i, ro, nx;
 128
 129         pt_dir = vmem_pte_alloc();
 130         if (!pt_dir)
 131                 return -ENOMEM;
 132         pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
 133         ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
 134         nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
 135         prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
 136         if (!nx)
 137                 prot &= ~_PAGE_NOEXEC;
 138         ptep = pt_dir;
 139         for (i = 0; i < PTRS_PER_PTE; i++) {
 140                 set_pte(ptep, __pte(pte_addr | prot));
 141                 pte_addr += PAGE_SIZE;
 142                 ptep++;
 143         }
 144         new = __pmd(__pa(pt_dir) | _SEGMENT_ENTRY);
 145         pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
 146         update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
 147         update_page_count(PG_DIRECT_MAP_1M, -1);
 148         return 0;
 149 }
 150
 151 static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
 152                             unsigned long flags)
 153 {
 154         pmd_t new = *pmdp;
 155
 156         if (flags & SET_MEMORY_RO)
 157                 new = pmd_wrprotect(new);
 158         else if (flags & SET_MEMORY_RW)
 159                 new = pmd_mkwrite_novma(pmd_mkdirty(new));
 160         if (flags & SET_MEMORY_NX)
 161                 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 162         else if (flags & SET_MEMORY_X)
 163                 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 164         if (flags & SET_MEMORY_INV) {
 165                 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
 166         } else if (flags & SET_MEMORY_DEF) {
 167                 new = __pmd(pmd_val(new) & PMD_MASK);
 168                 new = set_pmd_bit(new, SEGMENT_KERNEL);
 169                 if (!MACHINE_HAS_NX)
 170                         new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 171         }
 172         pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
 173 }
 174
 175 static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
 176                           unsigned long flags)
 177 {
 178         unsigned long next;
 179         int need_split;
 180         pmd_t *pmdp;
 181         int rc = 0;
 182
 183         pmdp = pmd_offset(pudp, addr);
 184         do {
 185                 if (pmd_none(*pmdp))
 186                         return -EINVAL;
 187                 next = pmd_addr_end(addr, end);
 188                 if (pmd_large(*pmdp)) {
 189                         need_split  = !!(flags & SET_MEMORY_4K);
 190                         need_split |= !!(addr & ~PMD_MASK);
 191                         need_split |= !!(addr + PMD_SIZE > next);
 192                         if (need_split) {
 193                                 rc = split_pmd_page(pmdp, addr);
 194                                 if (rc)
 195                                         return rc;
 196                                 continue;
 197                         }
 198                         modify_pmd_page(pmdp, addr, flags);
 199                 } else {
 200                         rc = walk_pte_level(pmdp, addr, next, flags);
 201                         if (rc)
 202                                 return rc;
 203                 }
 204                 pmdp++;
 205                 addr = next;
 206                 cond_resched();
 207         } while (addr < end);
 208         return rc;
 209 }
 210
 211 static int split_pud_page(pud_t *pudp, unsigned long addr)
 212 {
 213         unsigned long pmd_addr, prot;
 214         pmd_t *pm_dir, *pmdp;
 215         pud_t new;
 216         int i, ro, nx;
 217
 218         pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
 219         if (!pm_dir)
 220                 return -ENOMEM;
 221         pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
 222         ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
 223         nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
 224         prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
 225         if (!nx)
 226                 prot &= ~_SEGMENT_ENTRY_NOEXEC;
 227         pmdp = pm_dir;
 228         for (i = 0; i < PTRS_PER_PMD; i++) {
 229                 set_pmd(pmdp, __pmd(pmd_addr | prot));
 230                 pmd_addr += PMD_SIZE;
 231                 pmdp++;
 232         }
 233         new = __pud(__pa(pm_dir) | _REGION3_ENTRY);
 234         pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
 235         update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
 236         update_page_count(PG_DIRECT_MAP_2G, -1);
 237         return 0;
 238 }
 239
 240 static void modify_pud_page(pud_t *pudp, unsigned long addr,
 241                             unsigned long flags)
 242 {
 243         pud_t new = *pudp;
 244
 245         if (flags & SET_MEMORY_RO)
 246                 new = pud_wrprotect(new);
 247         else if (flags & SET_MEMORY_RW)
 248                 new = pud_mkwrite(pud_mkdirty(new));
 249         if (flags & SET_MEMORY_NX)
 250                 new = set_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
 251         else if (flags & SET_MEMORY_X)
 252                 new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
 253         if (flags & SET_MEMORY_INV) {
 254                 new = set_pud_bit(new, __pgprot(_REGION_ENTRY_INVALID));
 255         } else if (flags & SET_MEMORY_DEF) {
 256                 new = __pud(pud_val(new) & PUD_MASK);
 257                 new = set_pud_bit(new, REGION3_KERNEL);
 258                 if (!MACHINE_HAS_NX)
 259                         new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
 260         }
 261         pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
 262 }
 263
 264 static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
 265                           unsigned long flags)
 266 {
 267         unsigned long next;
 268         int need_split;
 269         pud_t *pudp;
 270         int rc = 0;
 271
 272         pudp = pud_offset(p4d, addr);
 273         do {
 274                 if (pud_none(*pudp))
 275                         return -EINVAL;
 276                 next = pud_addr_end(addr, end);
 277                 if (pud_large(*pudp)) {
 278                         need_split  = !!(flags & SET_MEMORY_4K);
 279                         need_split |= !!(addr & ~PUD_MASK);
 280                         need_split |= !!(addr + PUD_SIZE > next);
 281                         if (need_split) {
 282                                 rc = split_pud_page(pudp, addr);
 283                                 if (rc)
 284                                         break;
 285                                 continue;
 286                         }
 287                         modify_pud_page(pudp, addr, flags);
 288                 } else {
 289                         rc = walk_pmd_level(pudp, addr, next, flags);
 290                 }
 291                 pudp++;
 292                 addr = next;
 293                 cond_resched();
 294         } while (addr < end && !rc);
 295         return rc;
 296 }
 297
 298 static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
 299                           unsigned long flags)
 300 {
 301         unsigned long next;
 302         p4d_t *p4dp;
 303         int rc = 0;
 304
 305         p4dp = p4d_offset(pgd, addr);
 306         do {
 307                 if (p4d_none(*p4dp))
 308                         return -EINVAL;
 309                 next = p4d_addr_end(addr, end);
 310                 rc = walk_pud_level(p4dp, addr, next, flags);
 311                 p4dp++;
 312                 addr = next;
 313                 cond_resched();
 314         } while (addr < end && !rc);
 315         return rc;
 316 }
 317
 318 DEFINE_MUTEX(cpa_mutex);
 319
 320 static int change_page_attr(unsigned long addr, unsigned long end,
 321                             unsigned long flags)
 322 {
 323         unsigned long next;
 324         int rc = -EINVAL;
 325         pgd_t *pgdp;
 326
 327         pgdp = pgd_offset_k(addr);
 328         do {
 329                 if (pgd_none(*pgdp))
 330                         break;
 331                 next = pgd_addr_end(addr, end);
 332                 rc = walk_p4d_level(pgdp, addr, next, flags);
 333                 if (rc)
 334                         break;
 335                 cond_resched();
 336         } while (pgdp++, addr = next, addr < end && !rc);
 337         return rc;
 338 }
 339
 340 static int change_page_attr_alias(unsigned long addr, unsigned long end,
 341                                   unsigned long flags)
 342 {
 343         unsigned long alias, offset, va_start, va_end;
 344         struct vm_struct *area;
 345         int rc = 0;
 346
 347         /*
 348          * Changes to read-only permissions on kernel VA mappings are also
 349          * applied to the kernel direct mapping. Execute permissions are
 350          * intentionally not transferred to keep all allocated pages within
 351          * the direct mapping non-executable.
 352          */
 353         flags &= SET_MEMORY_RO | SET_MEMORY_RW;
 354         if (!flags)
 355                 return 0;
 356         area = NULL;
 357         while (addr < end) {
 358                 if (!area)
 359                         area = find_vm_area((void *)addr);
 360                 if (!area || !(area->flags & VM_ALLOC))
 361                         return 0;
 362                 va_start = (unsigned long)area->addr;
 363                 va_end = va_start + area->nr_pages * PAGE_SIZE;
 364                 offset = (addr - va_start) >> PAGE_SHIFT;
 365                 alias = (unsigned long)page_address(area->pages[offset]);
 366                 rc = change_page_attr(alias, alias + PAGE_SIZE, flags);
 367                 if (rc)
 368                         break;
 369                 addr += PAGE_SIZE;
 370                 if (addr >= va_end)
 371                         area = NULL;
 372         }
 373         return rc;
 374 }
 375
 376 int __set_memory(unsigned long addr, unsigned long numpages, unsigned long flags)
 377 {
 378         unsigned long end;
 379         int rc;
 380
 381         if (!MACHINE_HAS_NX)
 382                 flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
 383         if (!flags)
 384                 return 0;
 385         if (!numpages)
 386                 return 0;
 387         addr &= PAGE_MASK;
 388         end = addr + numpages * PAGE_SIZE;
 389         mutex_lock(&cpa_mutex);
 390         rc = change_page_attr(addr, end, flags);
 391         if (rc)
 392                 goto out;
 393         rc = change_page_attr_alias(addr, end, flags);
 394 out:
 395         mutex_unlock(&cpa_mutex);
 396         return rc;
 397 }
 398
 399 int set_direct_map_invalid_noflush(struct page *page)
 400 {
 401         return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_INV);
 402 }
 403
 404 int set_direct_map_default_noflush(struct page *page)
 405 {
 406         return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_DEF);
 407 }
 408
 409 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
 410
 411 static void ipte_range(pte_t *pte, unsigned long address, int nr)
 412 {
 413         int i;
 414
 415         if (test_facility(13)) {
 416                 __ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
 417                 return;
 418         }
 419         for (i = 0; i < nr; i++) {
 420                 __ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
 421                 address += PAGE_SIZE;
 422                 pte++;
 423         }
 424 }
 425
 426 void __kernel_map_pages(struct page *page, int numpages, int enable)
 427 {
 428         unsigned long address;
 429         pte_t *ptep, pte;
 430         int nr, i, j;
 431
 432         for (i = 0; i < numpages;) {
 433                 address = (unsigned long)page_to_virt(page + i);
 434                 ptep = virt_to_kpte(address);
 435                 nr = (unsigned long)ptep >> ilog2(sizeof(long));
 436                 nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
 437                 nr = min(numpages - i, nr);
 438                 if (enable) {
 439                         for (j = 0; j < nr; j++) {
 440                                 pte = clear_pte_bit(*ptep, __pgprot(_PAGE_INVALID));
 441                                 set_pte(ptep, pte);
 442                                 address += PAGE_SIZE;
 443                                 ptep++;
 444                         }
 445                 } else {
 446                         ipte_range(ptep, address, nr);
 447                 }
 448                 i += nr;
 449         }
 450 }
 451
 452 #endif /* CONFIG_DEBUG_PAGEALLOC */