arch/s390/mm/vmem.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Copyright IBM Corp. 2006
   4  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   5  */
   6
   7 #include <linux/memblock.h>
   8 #include <linux/pfn.h>
   9 #include <linux/mm.h>
  10 #include <linux/init.h>
  11 #include <linux/list.h>
  12 #include <linux/hugetlb.h>
  13 #include <linux/slab.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/pgalloc.h>
  16 #include <asm/pgtable.h>
  17 #include <asm/setup.h>
  18 #include <asm/tlbflush.h>
  19 #include <asm/sections.h>
  20 #include <asm/set_memory.h>
  21
  22 static DEFINE_MUTEX(vmem_mutex);
  23
  24 struct memory_segment {
  25         struct list_head list;
  26         unsigned long start;
  27         unsigned long size;
  28 };
  29
  30 static LIST_HEAD(mem_segs);
  31
  32 static void __ref *vmem_alloc_pages(unsigned int order)
  33 {
  34         unsigned long size = PAGE_SIZE << order;
  35
  36         if (slab_is_available())
  37                 return (void *)__get_free_pages(GFP_KERNEL, order);
  38         return (void *) memblock_phys_alloc(size, size);
  39 }
  40
  41 void *vmem_crst_alloc(unsigned long val)
  42 {
  43         unsigned long *table;
  44
  45         table = vmem_alloc_pages(CRST_ALLOC_ORDER);
  46         if (table)
  47                 crst_table_init(table, val);
  48         return table;
  49 }
  50
  51 pte_t __ref *vmem_pte_alloc(void)
  52 {
  53         unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
  54         pte_t *pte;
  55
  56         if (slab_is_available())
  57                 pte = (pte_t *) page_table_alloc(&init_mm);
  58         else
  59                 pte = (pte_t *) memblock_phys_alloc(size, size);
  60         if (!pte)
  61                 return NULL;
  62         memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
  63         return pte;
  64 }
  65
  66 /*
  67  * Add a physical memory range to the 1:1 mapping.
  68  */
  69 static int vmem_add_mem(unsigned long start, unsigned long size)
  70 {
  71         unsigned long pgt_prot, sgt_prot, r3_prot;
  72         unsigned long pages4k, pages1m, pages2g;
  73         unsigned long end = start + size;
  74         unsigned long address = start;
  75         pgd_t *pg_dir;
  76         p4d_t *p4_dir;
  77         pud_t *pu_dir;
  78         pmd_t *pm_dir;
  79         pte_t *pt_dir;
  80         int ret = -ENOMEM;
  81
  82         pgt_prot = pgprot_val(PAGE_KERNEL);
  83         sgt_prot = pgprot_val(SEGMENT_KERNEL);
  84         r3_prot = pgprot_val(REGION3_KERNEL);
  85         if (!MACHINE_HAS_NX) {
  86                 pgt_prot &= ~_PAGE_NOEXEC;
  87                 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
  88                 r3_prot &= ~_REGION_ENTRY_NOEXEC;
  89         }
  90         pages4k = pages1m = pages2g = 0;
  91         while (address < end) {
  92                 pg_dir = pgd_offset_k(address);
  93                 if (pgd_none(*pg_dir)) {
  94                         p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
  95                         if (!p4_dir)
  96                                 goto out;
  97                         pgd_populate(&init_mm, pg_dir, p4_dir);
  98                 }
  99                 p4_dir = p4d_offset(pg_dir, address);
 100                 if (p4d_none(*p4_dir)) {
 101                         pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
 102                         if (!pu_dir)
 103                                 goto out;
 104                         p4d_populate(&init_mm, p4_dir, pu_dir);
 105                 }
 106                 pu_dir = pud_offset(p4_dir, address);
 107                 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
 108                     !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&
 109                      !debug_pagealloc_enabled()) {
 110                         pud_val(*pu_dir) = address | r3_prot;
 111                         address += PUD_SIZE;
 112                         pages2g++;
 113                         continue;
 114                 }
 115                 if (pud_none(*pu_dir)) {
 116                         pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
 117                         if (!pm_dir)
 118                                 goto out;
 119                         pud_populate(&init_mm, pu_dir, pm_dir);
 120                 }
 121                 pm_dir = pmd_offset(pu_dir, address);
 122                 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
 123                     !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&
 124                     !debug_pagealloc_enabled()) {
 125                         pmd_val(*pm_dir) = address | sgt_prot;
 126                         address += PMD_SIZE;
 127                         pages1m++;
 128                         continue;
 129                 }
 130                 if (pmd_none(*pm_dir)) {
 131                         pt_dir = vmem_pte_alloc();
 132                         if (!pt_dir)
 133                                 goto out;
 134                         pmd_populate(&init_mm, pm_dir, pt_dir);
 135                 }
 136
 137                 pt_dir = pte_offset_kernel(pm_dir, address);
 138                 pte_val(*pt_dir) = address | pgt_prot;
 139                 address += PAGE_SIZE;
 140                 pages4k++;
 141         }
 142         ret = 0;
 143 out:
 144         update_page_count(PG_DIRECT_MAP_4K, pages4k);
 145         update_page_count(PG_DIRECT_MAP_1M, pages1m);
 146         update_page_count(PG_DIRECT_MAP_2G, pages2g);
 147         return ret;
 148 }
 149
 150 /*
 151  * Remove a physical memory range from the 1:1 mapping.
 152  * Currently only invalidates page table entries.
 153  */
 154 static void vmem_remove_range(unsigned long start, unsigned long size)
 155 {
 156         unsigned long pages4k, pages1m, pages2g;
 157         unsigned long end = start + size;
 158         unsigned long address = start;
 159         pgd_t *pg_dir;
 160         p4d_t *p4_dir;
 161         pud_t *pu_dir;
 162         pmd_t *pm_dir;
 163         pte_t *pt_dir;
 164
 165         pages4k = pages1m = pages2g = 0;
 166         while (address < end) {
 167                 pg_dir = pgd_offset_k(address);
 168                 if (pgd_none(*pg_dir)) {
 169                         address += PGDIR_SIZE;
 170                         continue;
 171                 }
 172                 p4_dir = p4d_offset(pg_dir, address);
 173                 if (p4d_none(*p4_dir)) {
 174                         address += P4D_SIZE;
 175                         continue;
 176                 }
 177                 pu_dir = pud_offset(p4_dir, address);
 178                 if (pud_none(*pu_dir)) {
 179                         address += PUD_SIZE;
 180                         continue;
 181                 }
 182                 if (pud_large(*pu_dir)) {
 183                         pud_clear(pu_dir);
 184                         address += PUD_SIZE;
 185                         pages2g++;
 186                         continue;
 187                 }
 188                 pm_dir = pmd_offset(pu_dir, address);
 189                 if (pmd_none(*pm_dir)) {
 190                         address += PMD_SIZE;
 191                         continue;
 192                 }
 193                 if (pmd_large(*pm_dir)) {
 194                         pmd_clear(pm_dir);
 195                         address += PMD_SIZE;
 196                         pages1m++;
 197                         continue;
 198                 }
 199                 pt_dir = pte_offset_kernel(pm_dir, address);
 200                 pte_clear(&init_mm, address, pt_dir);
 201                 address += PAGE_SIZE;
 202                 pages4k++;
 203         }
 204         flush_tlb_kernel_range(start, end);
 205         update_page_count(PG_DIRECT_MAP_4K, -pages4k);
 206         update_page_count(PG_DIRECT_MAP_1M, -pages1m);
 207         update_page_count(PG_DIRECT_MAP_2G, -pages2g);
 208 }
 209
 210 /*
 211  * Add a backed mem_map array to the virtual mem_map array.
 212  */
 213 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 214                 struct vmem_altmap *altmap)
 215 {
 216         unsigned long pgt_prot, sgt_prot;
 217         unsigned long address = start;
 218         pgd_t *pg_dir;
 219         p4d_t *p4_dir;
 220         pud_t *pu_dir;
 221         pmd_t *pm_dir;
 222         pte_t *pt_dir;
 223         int ret = -ENOMEM;
 224
 225         pgt_prot = pgprot_val(PAGE_KERNEL);
 226         sgt_prot = pgprot_val(SEGMENT_KERNEL);
 227         if (!MACHINE_HAS_NX) {
 228                 pgt_prot &= ~_PAGE_NOEXEC;
 229                 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
 230         }
 231         for (address = start; address < end;) {
 232                 pg_dir = pgd_offset_k(address);
 233                 if (pgd_none(*pg_dir)) {
 234                         p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
 235                         if (!p4_dir)
 236                                 goto out;
 237                         pgd_populate(&init_mm, pg_dir, p4_dir);
 238                 }
 239
 240                 p4_dir = p4d_offset(pg_dir, address);
 241                 if (p4d_none(*p4_dir)) {
 242                         pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
 243                         if (!pu_dir)
 244                                 goto out;
 245                         p4d_populate(&init_mm, p4_dir, pu_dir);
 246                 }
 247
 248                 pu_dir = pud_offset(p4_dir, address);
 249                 if (pud_none(*pu_dir)) {
 250                         pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
 251                         if (!pm_dir)
 252                                 goto out;
 253                         pud_populate(&init_mm, pu_dir, pm_dir);
 254                 }
 255
 256                 pm_dir = pmd_offset(pu_dir, address);
 257                 if (pmd_none(*pm_dir)) {
 258                         /* Use 1MB frames for vmemmap if available. We always
 259                          * use large frames even if they are only partially
 260                          * used.
 261                          * Otherwise we would have also page tables since
 262                          * vmemmap_populate gets called for each section
 263                          * separately. */
 264                         if (MACHINE_HAS_EDAT1) {
 265                                 void *new_page;
 266
 267                                 new_page = vmemmap_alloc_block(PMD_SIZE, node);
 268                                 if (!new_page)
 269                                         goto out;
 270                                 pmd_val(*pm_dir) = __pa(new_page) | sgt_prot;
 271                                 address = (address + PMD_SIZE) & PMD_MASK;
 272                                 continue;
 273                         }
 274                         pt_dir = vmem_pte_alloc();
 275                         if (!pt_dir)
 276                                 goto out;
 277                         pmd_populate(&init_mm, pm_dir, pt_dir);
 278                 } else if (pmd_large(*pm_dir)) {
 279                         address = (address + PMD_SIZE) & PMD_MASK;
 280                         continue;
 281                 }
 282
 283                 pt_dir = pte_offset_kernel(pm_dir, address);
 284                 if (pte_none(*pt_dir)) {
 285                         void *new_page;
 286
 287                         new_page = vmemmap_alloc_block(PAGE_SIZE, node);
 288                         if (!new_page)
 289                                 goto out;
 290                         pte_val(*pt_dir) = __pa(new_page) | pgt_prot;
 291                 }
 292                 address += PAGE_SIZE;
 293         }
 294         ret = 0;
 295 out:
 296         return ret;
 297 }
 298
 299 void vmemmap_free(unsigned long start, unsigned long end,
 300                 struct vmem_altmap *altmap)
 301 {
 302 }
 303
 304 /*
 305  * Add memory segment to the segment list if it doesn't overlap with
 306  * an already present segment.
 307  */
 308 static int insert_memory_segment(struct memory_segment *seg)
 309 {
 310         struct memory_segment *tmp;
 311
 312         if (seg->start + seg->size > VMEM_MAX_PHYS ||
 313             seg->start + seg->size < seg->start)
 314                 return -ERANGE;
 315
 316         list_for_each_entry(tmp, &mem_segs, list) {
 317                 if (seg->start >= tmp->start + tmp->size)
 318                         continue;
 319                 if (seg->start + seg->size <= tmp->start)
 320                         continue;
 321                 return -ENOSPC;
 322         }
 323         list_add(&seg->list, &mem_segs);
 324         return 0;
 325 }
 326
 327 /*
 328  * Remove memory segment from the segment list.
 329  */
 330 static void remove_memory_segment(struct memory_segment *seg)
 331 {
 332         list_del(&seg->list);
 333 }
 334
 335 static void __remove_shared_memory(struct memory_segment *seg)
 336 {
 337         remove_memory_segment(seg);
 338         vmem_remove_range(seg->start, seg->size);
 339 }
 340
 341 int vmem_remove_mapping(unsigned long start, unsigned long size)
 342 {
 343         struct memory_segment *seg;
 344         int ret;
 345
 346         mutex_lock(&vmem_mutex);
 347
 348         ret = -ENOENT;
 349         list_for_each_entry(seg, &mem_segs, list) {
 350                 if (seg->start == start && seg->size == size)
 351                         break;
 352         }
 353
 354         if (seg->start != start || seg->size != size)
 355                 goto out;
 356
 357         ret = 0;
 358         __remove_shared_memory(seg);
 359         kfree(seg);
 360 out:
 361         mutex_unlock(&vmem_mutex);
 362         return ret;
 363 }
 364
 365 int vmem_add_mapping(unsigned long start, unsigned long size)
 366 {
 367         struct memory_segment *seg;
 368         int ret;
 369
 370         mutex_lock(&vmem_mutex);
 371         ret = -ENOMEM;
 372         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 373         if (!seg)
 374                 goto out;
 375         seg->start = start;
 376         seg->size = size;
 377
 378         ret = insert_memory_segment(seg);
 379         if (ret)
 380                 goto out_free;
 381
 382         ret = vmem_add_mem(start, size);
 383         if (ret)
 384                 goto out_remove;
 385         goto out;
 386
 387 out_remove:
 388         __remove_shared_memory(seg);
 389 out_free:
 390         kfree(seg);
 391 out:
 392         mutex_unlock(&vmem_mutex);
 393         return ret;
 394 }
 395
 396 /*
 397  * map whole physical memory to virtual memory (identity mapping)
 398  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 399  * additional memory segments.
 400  */
 401 void __init vmem_map_init(void)
 402 {
 403         struct memblock_region *reg;
 404
 405         for_each_memblock(memory, reg)
 406                 vmem_add_mem(reg->base, reg->size);
 407         __set_memory((unsigned long)_stext,
 408                      (unsigned long)(_etext - _stext) >> PAGE_SHIFT,
 409                      SET_MEMORY_RO | SET_MEMORY_X);
 410         __set_memory((unsigned long)_etext,
 411                      (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
 412                      SET_MEMORY_RO);
 413         __set_memory((unsigned long)_sinittext,
 414                      (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
 415                      SET_MEMORY_RO | SET_MEMORY_X);
 416         __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT,
 417                      SET_MEMORY_RO | SET_MEMORY_X);
 418         pr_info("Write protected kernel read-only data: %luk\n",
 419                 (unsigned long)(__end_rodata - _stext) >> 10);
 420 }
 421
 422 /*
 423  * Convert memblock.memory  to a memory segment list so there is a single
 424  * list that contains all memory segments.
 425  */
 426 static int __init vmem_convert_memory_chunk(void)
 427 {
 428         struct memblock_region *reg;
 429         struct memory_segment *seg;
 430
 431         mutex_lock(&vmem_mutex);
 432         for_each_memblock(memory, reg) {
 433                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 434                 if (!seg)
 435                         panic("Out of memory...\n");
 436                 seg->start = reg->base;
 437                 seg->size = reg->size;
 438                 insert_memory_segment(seg);
 439         }
 440         mutex_unlock(&vmem_mutex);
 441         return 0;
 442 }
 443
 444 core_initcall(vmem_convert_memory_chunk);