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/mm.h>
   8 #include <asm/cacheflush.h>
   9 #include <asm/facility.h>
  10 #include <asm/pgalloc.h>
  11 #include <asm/kfence.h>
  12 #include <asm/page.h>
  13 #include <asm/set_memory.h>
  14
  15 static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
  16 {
  17         asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],1,0"
  18                      : [addr] "+a" (addr) : [skey] "d" (skey));
  19         return addr;
  20 }
  21
  22 void __storage_key_init_range(unsigned long start, unsigned long end)
  23 {
  24         unsigned long boundary, size;
  25
  26         while (start < end) {
  27                 if (MACHINE_HAS_EDAT1) {
  28                         /* set storage keys for a 1MB frame */
  29                         size = 1UL << 20;
  30                         boundary = (start + size) & ~(size - 1);
  31                         if (boundary <= end) {
  32                                 do {
  33                                         start = sske_frame(start, PAGE_DEFAULT_KEY);
  34                                 } while (start < boundary);
  35                                 continue;
  36                         }
  37                 }
  38                 page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
  39                 start += PAGE_SIZE;
  40         }
  41 }
  42
  43 #ifdef CONFIG_PROC_FS
  44 atomic_long_t direct_pages_count[PG_DIRECT_MAP_MAX];
  45
  46 void arch_report_meminfo(struct seq_file *m)
  47 {
  48         seq_printf(m, "DirectMap4k:    %8lu kB\n",
  49                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
  50         seq_printf(m, "DirectMap1M:    %8lu kB\n",
  51                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
  52         seq_printf(m, "DirectMap2G:    %8lu kB\n",
  53                    atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
  54 }
  55 #endif /* CONFIG_PROC_FS */
  56
  57 static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
  58                     unsigned long dtt)
  59 {
  60         unsigned long table, mask;
  61
  62         mask = 0;
  63         if (MACHINE_HAS_EDAT2) {
  64                 switch (dtt) {
  65                 case CRDTE_DTT_REGION3:
  66                         mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
  67                         break;
  68                 case CRDTE_DTT_SEGMENT:
  69                         mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
  70                         break;
  71                 case CRDTE_DTT_PAGE:
  72                         mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
  73                         break;
  74                 }
  75                 table = (unsigned long)old & mask;
  76                 crdte(*old, new, table, dtt, addr, S390_lowcore.kernel_asce);
  77         } else if (MACHINE_HAS_IDTE) {
  78                 cspg(old, *old, new);
  79         } else {
  80                 csp((unsigned int *)old + 1, *old, new);
  81         }
  82 }
  83
  84 static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
  85                           unsigned long flags)
  86 {
  87         pte_t *ptep, new;
  88
  89         if (flags == SET_MEMORY_4K)
  90                 return 0;
  91         ptep = pte_offset_kernel(pmdp, addr);
  92         do {
  93                 new = *ptep;
  94                 if (pte_none(new))
  95                         return -EINVAL;
  96                 if (flags & SET_MEMORY_RO)
  97                         new = pte_wrprotect(new);
  98                 else if (flags & SET_MEMORY_RW)
  99                         new = pte_mkwrite(pte_mkdirty(new));
 100                 if (flags & SET_MEMORY_NX)
 101                         pte_val(new) |= _PAGE_NOEXEC;
 102                 else if (flags & SET_MEMORY_X)
 103                         pte_val(new) &= ~_PAGE_NOEXEC;
 104                 pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
 105                 ptep++;
 106                 addr += PAGE_SIZE;
 107                 cond_resched();
 108         } while (addr < end);
 109         return 0;
 110 }
 111
 112 static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
 113 {
 114         unsigned long pte_addr, prot;
 115         pte_t *pt_dir, *ptep;
 116         pmd_t new;
 117         int i, ro, nx;
 118
 119         pt_dir = vmem_pte_alloc();
 120         if (!pt_dir)
 121                 return -ENOMEM;
 122         pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
 123         ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
 124         nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
 125         prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
 126         if (!nx)
 127                 prot &= ~_PAGE_NOEXEC;
 128         ptep = pt_dir;
 129         for (i = 0; i < PTRS_PER_PTE; i++) {
 130                 pte_val(*ptep) = pte_addr | prot;
 131                 pte_addr += PAGE_SIZE;
 132                 ptep++;
 133         }
 134         pmd_val(new) = __pa(pt_dir) | _SEGMENT_ENTRY;
 135         pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
 136         update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
 137         update_page_count(PG_DIRECT_MAP_1M, -1);
 138         return 0;
 139 }
 140
 141 static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
 142                             unsigned long flags)
 143 {
 144         pmd_t new = *pmdp;
 145
 146         if (flags & SET_MEMORY_RO)
 147                 new = pmd_wrprotect(new);
 148         else if (flags & SET_MEMORY_RW)
 149                 new = pmd_mkwrite(pmd_mkdirty(new));
 150         if (flags & SET_MEMORY_NX)
 151                 pmd_val(new) |= _SEGMENT_ENTRY_NOEXEC;
 152         else if (flags & SET_MEMORY_X)
 153                 pmd_val(new) &= ~_SEGMENT_ENTRY_NOEXEC;
 154         pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
 155 }
 156
 157 static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
 158                           unsigned long flags)
 159 {
 160         unsigned long next;
 161         int need_split;
 162         pmd_t *pmdp;
 163         int rc = 0;
 164
 165         pmdp = pmd_offset(pudp, addr);
 166         do {
 167                 if (pmd_none(*pmdp))
 168                         return -EINVAL;
 169                 next = pmd_addr_end(addr, end);
 170                 if (pmd_large(*pmdp)) {
 171                         need_split  = !!(flags & SET_MEMORY_4K);
 172                         need_split |= !!(addr & ~PMD_MASK);
 173                         need_split |= !!(addr + PMD_SIZE > next);
 174                         if (need_split) {
 175                                 rc = split_pmd_page(pmdp, addr);
 176                                 if (rc)
 177                                         return rc;
 178                                 continue;
 179                         }
 180                         modify_pmd_page(pmdp, addr, flags);
 181                 } else {
 182                         rc = walk_pte_level(pmdp, addr, next, flags);
 183                         if (rc)
 184                                 return rc;
 185                 }
 186                 pmdp++;
 187                 addr = next;
 188                 cond_resched();
 189         } while (addr < end);
 190         return rc;
 191 }
 192
 193 static int split_pud_page(pud_t *pudp, unsigned long addr)
 194 {
 195         unsigned long pmd_addr, prot;
 196         pmd_t *pm_dir, *pmdp;
 197         pud_t new;
 198         int i, ro, nx;
 199
 200         pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
 201         if (!pm_dir)
 202                 return -ENOMEM;
 203         pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
 204         ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
 205         nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
 206         prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
 207         if (!nx)
 208                 prot &= ~_SEGMENT_ENTRY_NOEXEC;
 209         pmdp = pm_dir;
 210         for (i = 0; i < PTRS_PER_PMD; i++) {
 211                 pmd_val(*pmdp) = pmd_addr | prot;
 212                 pmd_addr += PMD_SIZE;
 213                 pmdp++;
 214         }
 215         pud_val(new) = __pa(pm_dir) | _REGION3_ENTRY;
 216         pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
 217         update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
 218         update_page_count(PG_DIRECT_MAP_2G, -1);
 219         return 0;
 220 }
 221
 222 static void modify_pud_page(pud_t *pudp, unsigned long addr,
 223                             unsigned long flags)
 224 {
 225         pud_t new = *pudp;
 226
 227         if (flags & SET_MEMORY_RO)
 228                 new = pud_wrprotect(new);
 229         else if (flags & SET_MEMORY_RW)
 230                 new = pud_mkwrite(pud_mkdirty(new));
 231         if (flags & SET_MEMORY_NX)
 232                 pud_val(new) |= _REGION_ENTRY_NOEXEC;
 233         else if (flags & SET_MEMORY_X)
 234                 pud_val(new) &= ~_REGION_ENTRY_NOEXEC;
 235         pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
 236 }
 237
 238 static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
 239                           unsigned long flags)
 240 {
 241         unsigned long next;
 242         int need_split;
 243         pud_t *pudp;
 244         int rc = 0;
 245
 246         pudp = pud_offset(p4d, addr);
 247         do {
 248                 if (pud_none(*pudp))
 249                         return -EINVAL;
 250                 next = pud_addr_end(addr, end);
 251                 if (pud_large(*pudp)) {
 252                         need_split  = !!(flags & SET_MEMORY_4K);
 253                         need_split |= !!(addr & ~PUD_MASK);
 254                         need_split |= !!(addr + PUD_SIZE > next);
 255                         if (need_split) {
 256                                 rc = split_pud_page(pudp, addr);
 257                                 if (rc)
 258                                         break;
 259                                 continue;
 260                         }
 261                         modify_pud_page(pudp, addr, flags);
 262                 } else {
 263                         rc = walk_pmd_level(pudp, addr, next, flags);
 264                 }
 265                 pudp++;
 266                 addr = next;
 267                 cond_resched();
 268         } while (addr < end && !rc);
 269         return rc;
 270 }
 271
 272 static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
 273                           unsigned long flags)
 274 {
 275         unsigned long next;
 276         p4d_t *p4dp;
 277         int rc = 0;
 278
 279         p4dp = p4d_offset(pgd, addr);
 280         do {
 281                 if (p4d_none(*p4dp))
 282                         return -EINVAL;
 283                 next = p4d_addr_end(addr, end);
 284                 rc = walk_pud_level(p4dp, addr, next, flags);
 285                 p4dp++;
 286                 addr = next;
 287                 cond_resched();
 288         } while (addr < end && !rc);
 289         return rc;
 290 }
 291
 292 DEFINE_MUTEX(cpa_mutex);
 293
 294 static int change_page_attr(unsigned long addr, unsigned long end,
 295                             unsigned long flags)
 296 {
 297         unsigned long next;
 298         int rc = -EINVAL;
 299         pgd_t *pgdp;
 300
 301         if (addr == end)
 302                 return 0;
 303         if (end >= MODULES_END)
 304                 return -EINVAL;
 305         mutex_lock(&cpa_mutex);
 306         pgdp = pgd_offset_k(addr);
 307         do {
 308                 if (pgd_none(*pgdp))
 309                         break;
 310                 next = pgd_addr_end(addr, end);
 311                 rc = walk_p4d_level(pgdp, addr, next, flags);
 312                 if (rc)
 313                         break;
 314                 cond_resched();
 315         } while (pgdp++, addr = next, addr < end && !rc);
 316         mutex_unlock(&cpa_mutex);
 317         return rc;
 318 }
 319
 320 int __set_memory(unsigned long addr, int numpages, unsigned long flags)
 321 {
 322         if (!MACHINE_HAS_NX)
 323                 flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
 324         if (!flags)
 325                 return 0;
 326         addr &= PAGE_MASK;
 327         return change_page_attr(addr, addr + numpages * PAGE_SIZE, flags);
 328 }
 329
 330 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
 331
 332 static void ipte_range(pte_t *pte, unsigned long address, int nr)
 333 {
 334         int i;
 335
 336         if (test_facility(13)) {
 337                 __ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
 338                 return;
 339         }
 340         for (i = 0; i < nr; i++) {
 341                 __ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
 342                 address += PAGE_SIZE;
 343                 pte++;
 344         }
 345 }
 346
 347 void __kernel_map_pages(struct page *page, int numpages, int enable)
 348 {
 349         unsigned long address;
 350         int nr, i, j;
 351         pte_t *pte;
 352
 353         for (i = 0; i < numpages;) {
 354                 address = (unsigned long)page_to_virt(page + i);
 355                 pte = virt_to_kpte(address);
 356                 nr = (unsigned long)pte >> ilog2(sizeof(long));
 357                 nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
 358                 nr = min(numpages - i, nr);
 359                 if (enable) {
 360                         for (j = 0; j < nr; j++) {
 361                                 pte_val(*pte) &= ~_PAGE_INVALID;
 362                                 address += PAGE_SIZE;
 363                                 pte++;
 364                         }
 365                 } else {
 366                         ipte_range(pte, address, nr);
 367                 }
 368                 i += nr;
 369         }
 370 }
 371
 372 #endif /* CONFIG_DEBUG_PAGEALLOC */