arch/s390/mm/vmem.c

   1 /*
   2  *    Copyright IBM Corp. 2006
   3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   4  */
   5
   6 #include <linux/bootmem.h>
   7 #include <linux/pfn.h>
   8 #include <linux/mm.h>
   9 #include <linux/module.h>
  10 #include <linux/list.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/slab.h>
  13 #include <linux/memblock.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/setup.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/sections.h>
  19
  20 static DEFINE_MUTEX(vmem_mutex);
  21
  22 struct memory_segment {
  23         struct list_head list;
  24         unsigned long start;
  25         unsigned long size;
  26 };
  27
  28 static LIST_HEAD(mem_segs);
  29
  30 static void __ref *vmem_alloc_pages(unsigned int order)
  31 {
  32         if (slab_is_available())
  33                 return (void *)__get_free_pages(GFP_KERNEL, order);
  34         return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
  35 }
  36
  37 static inline pud_t *vmem_pud_alloc(void)
  38 {
  39         pud_t *pud = NULL;
  40
  41 #ifdef CONFIG_64BIT
  42         pud = vmem_alloc_pages(2);
  43         if (!pud)
  44                 return NULL;
  45         clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
  46 #endif
  47         return pud;
  48 }
  49
  50 static inline pmd_t *vmem_pmd_alloc(void)
  51 {
  52         pmd_t *pmd = NULL;
  53
  54 #ifdef CONFIG_64BIT
  55         pmd = vmem_alloc_pages(2);
  56         if (!pmd)
  57                 return NULL;
  58         clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
  59 #endif
  60         return pmd;
  61 }
  62
  63 static pte_t __ref *vmem_pte_alloc(unsigned long address)
  64 {
  65         pte_t *pte;
  66
  67         if (slab_is_available())
  68                 pte = (pte_t *) page_table_alloc(&init_mm);
  69         else
  70                 pte = alloc_bootmem_align(PTRS_PER_PTE * sizeof(pte_t),
  71                                           PTRS_PER_PTE * sizeof(pte_t));
  72         if (!pte)
  73                 return NULL;
  74         clear_table((unsigned long *) pte, _PAGE_INVALID,
  75                     PTRS_PER_PTE * sizeof(pte_t));
  76         return pte;
  77 }
  78
  79 /*
  80  * Add a physical memory range to the 1:1 mapping.
  81  */
  82 static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
  83 {
  84         unsigned long end = start + size;
  85         unsigned long address = start;
  86         pgd_t *pg_dir;
  87         pud_t *pu_dir;
  88         pmd_t *pm_dir;
  89         pte_t *pt_dir;
  90         int ret = -ENOMEM;
  91
  92         while (address < end) {
  93                 pg_dir = pgd_offset_k(address);
  94                 if (pgd_none(*pg_dir)) {
  95                         pu_dir = vmem_pud_alloc();
  96                         if (!pu_dir)
  97                                 goto out;
  98                         pgd_populate(&init_mm, pg_dir, pu_dir);
  99                 }
 100                 pu_dir = pud_offset(pg_dir, address);
 101 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
 102                 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
 103                     !(address & ~PUD_MASK) && (address + PUD_SIZE <= end)) {
 104                         pud_val(*pu_dir) = __pa(address) |
 105                                 _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE |
 106                                 (ro ? _REGION_ENTRY_PROTECT : 0);
 107                         address += PUD_SIZE;
 108                         continue;
 109                 }
 110 #endif
 111                 if (pud_none(*pu_dir)) {
 112                         pm_dir = vmem_pmd_alloc();
 113                         if (!pm_dir)
 114                                 goto out;
 115                         pud_populate(&init_mm, pu_dir, pm_dir);
 116                 }
 117                 pm_dir = pmd_offset(pu_dir, address);
 118 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
 119                 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
 120                     !(address & ~PMD_MASK) && (address + PMD_SIZE <= end)) {
 121                         pmd_val(*pm_dir) = __pa(address) |
 122                                 _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE |
 123                                 _SEGMENT_ENTRY_YOUNG |
 124                                 (ro ? _SEGMENT_ENTRY_PROTECT : 0);
 125                         address += PMD_SIZE;
 126                         continue;
 127                 }
 128 #endif
 129                 if (pmd_none(*pm_dir)) {
 130                         pt_dir = vmem_pte_alloc(address);
 131                         if (!pt_dir)
 132                                 goto out;
 133                         pmd_populate(&init_mm, pm_dir, pt_dir);
 134                 }
 135
 136                 pt_dir = pte_offset_kernel(pm_dir, address);
 137                 pte_val(*pt_dir) = __pa(address) |
 138                         pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
 139                 address += PAGE_SIZE;
 140         }
 141         ret = 0;
 142 out:
 143         return ret;
 144 }
 145
 146 /*
 147  * Remove a physical memory range from the 1:1 mapping.
 148  * Currently only invalidates page table entries.
 149  */
 150 static void vmem_remove_range(unsigned long start, unsigned long size)
 151 {
 152         unsigned long end = start + size;
 153         unsigned long address = start;
 154         pgd_t *pg_dir;
 155         pud_t *pu_dir;
 156         pmd_t *pm_dir;
 157         pte_t *pt_dir;
 158         pte_t  pte;
 159
 160         pte_val(pte) = _PAGE_INVALID;
 161         while (address < end) {
 162                 pg_dir = pgd_offset_k(address);
 163                 if (pgd_none(*pg_dir)) {
 164                         address += PGDIR_SIZE;
 165                         continue;
 166                 }
 167                 pu_dir = pud_offset(pg_dir, address);
 168                 if (pud_none(*pu_dir)) {
 169                         address += PUD_SIZE;
 170                         continue;
 171                 }
 172                 if (pud_large(*pu_dir)) {
 173                         pud_clear(pu_dir);
 174                         address += PUD_SIZE;
 175                         continue;
 176                 }
 177                 pm_dir = pmd_offset(pu_dir, address);
 178                 if (pmd_none(*pm_dir)) {
 179                         address += PMD_SIZE;
 180                         continue;
 181                 }
 182                 if (pmd_large(*pm_dir)) {
 183                         pmd_clear(pm_dir);
 184                         address += PMD_SIZE;
 185                         continue;
 186                 }
 187                 pt_dir = pte_offset_kernel(pm_dir, address);
 188                 *pt_dir = pte;
 189                 address += PAGE_SIZE;
 190         }
 191         flush_tlb_kernel_range(start, end);
 192 }
 193
 194 /*
 195  * Add a backed mem_map array to the virtual mem_map array.
 196  */
 197 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 198 {
 199         unsigned long address = start;
 200         pgd_t *pg_dir;
 201         pud_t *pu_dir;
 202         pmd_t *pm_dir;
 203         pte_t *pt_dir;
 204         int ret = -ENOMEM;
 205
 206         for (address = start; address < end;) {
 207                 pg_dir = pgd_offset_k(address);
 208                 if (pgd_none(*pg_dir)) {
 209                         pu_dir = vmem_pud_alloc();
 210                         if (!pu_dir)
 211                                 goto out;
 212                         pgd_populate(&init_mm, pg_dir, pu_dir);
 213                 }
 214
 215                 pu_dir = pud_offset(pg_dir, address);
 216                 if (pud_none(*pu_dir)) {
 217                         pm_dir = vmem_pmd_alloc();
 218                         if (!pm_dir)
 219                                 goto out;
 220                         pud_populate(&init_mm, pu_dir, pm_dir);
 221                 }
 222
 223                 pm_dir = pmd_offset(pu_dir, address);
 224                 if (pmd_none(*pm_dir)) {
 225 #ifdef CONFIG_64BIT
 226                         /* Use 1MB frames for vmemmap if available. We always
 227                          * use large frames even if they are only partially
 228                          * used.
 229                          * Otherwise we would have also page tables since
 230                          * vmemmap_populate gets called for each section
 231                          * separately. */
 232                         if (MACHINE_HAS_EDAT1) {
 233                                 void *new_page;
 234
 235                                 new_page = vmemmap_alloc_block(PMD_SIZE, node);
 236                                 if (!new_page)
 237                                         goto out;
 238                                 pmd_val(*pm_dir) = __pa(new_page) |
 239                                         _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE;
 240                                 address = (address + PMD_SIZE) & PMD_MASK;
 241                                 continue;
 242                         }
 243 #endif
 244                         pt_dir = vmem_pte_alloc(address);
 245                         if (!pt_dir)
 246                                 goto out;
 247                         pmd_populate(&init_mm, pm_dir, pt_dir);
 248                 } else if (pmd_large(*pm_dir)) {
 249                         address = (address + PMD_SIZE) & PMD_MASK;
 250                         continue;
 251                 }
 252
 253                 pt_dir = pte_offset_kernel(pm_dir, address);
 254                 if (pte_none(*pt_dir)) {
 255                         void *new_page;
 256
 257                         new_page = vmemmap_alloc_block(PAGE_SIZE, node);
 258                         if (!new_page)
 259                                 goto out;
 260                         pte_val(*pt_dir) =
 261                                 __pa(new_page) | pgprot_val(PAGE_KERNEL);
 262                 }
 263                 address += PAGE_SIZE;
 264         }
 265         ret = 0;
 266 out:
 267         return ret;
 268 }
 269
 270 void vmemmap_free(unsigned long start, unsigned long end)
 271 {
 272 }
 273
 274 /*
 275  * Add memory segment to the segment list if it doesn't overlap with
 276  * an already present segment.
 277  */
 278 static int insert_memory_segment(struct memory_segment *seg)
 279 {
 280         struct memory_segment *tmp;
 281
 282         if (seg->start + seg->size > VMEM_MAX_PHYS ||
 283             seg->start + seg->size < seg->start)
 284                 return -ERANGE;
 285
 286         list_for_each_entry(tmp, &mem_segs, list) {
 287                 if (seg->start >= tmp->start + tmp->size)
 288                         continue;
 289                 if (seg->start + seg->size <= tmp->start)
 290                         continue;
 291                 return -ENOSPC;
 292         }
 293         list_add(&seg->list, &mem_segs);
 294         return 0;
 295 }
 296
 297 /*
 298  * Remove memory segment from the segment list.
 299  */
 300 static void remove_memory_segment(struct memory_segment *seg)
 301 {
 302         list_del(&seg->list);
 303 }
 304
 305 static void __remove_shared_memory(struct memory_segment *seg)
 306 {
 307         remove_memory_segment(seg);
 308         vmem_remove_range(seg->start, seg->size);
 309 }
 310
 311 int vmem_remove_mapping(unsigned long start, unsigned long size)
 312 {
 313         struct memory_segment *seg;
 314         int ret;
 315
 316         mutex_lock(&vmem_mutex);
 317
 318         ret = -ENOENT;
 319         list_for_each_entry(seg, &mem_segs, list) {
 320                 if (seg->start == start && seg->size == size)
 321                         break;
 322         }
 323
 324         if (seg->start != start || seg->size != size)
 325                 goto out;
 326
 327         ret = 0;
 328         __remove_shared_memory(seg);
 329         kfree(seg);
 330 out:
 331         mutex_unlock(&vmem_mutex);
 332         return ret;
 333 }
 334
 335 int vmem_add_mapping(unsigned long start, unsigned long size)
 336 {
 337         struct memory_segment *seg;
 338         int ret;
 339
 340         mutex_lock(&vmem_mutex);
 341         ret = -ENOMEM;
 342         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 343         if (!seg)
 344                 goto out;
 345         seg->start = start;
 346         seg->size = size;
 347
 348         ret = insert_memory_segment(seg);
 349         if (ret)
 350                 goto out_free;
 351
 352         ret = vmem_add_mem(start, size, 0);
 353         if (ret)
 354                 goto out_remove;
 355         goto out;
 356
 357 out_remove:
 358         __remove_shared_memory(seg);
 359 out_free:
 360         kfree(seg);
 361 out:
 362         mutex_unlock(&vmem_mutex);
 363         return ret;
 364 }
 365
 366 /*
 367  * map whole physical memory to virtual memory (identity mapping)
 368  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 369  * additional memory segments.
 370  */
 371 void __init vmem_map_init(void)
 372 {
 373         unsigned long ro_start, ro_end;
 374         struct memblock_region *reg;
 375         phys_addr_t start, end;
 376
 377         ro_start = PFN_ALIGN((unsigned long)&_stext);
 378         ro_end = (unsigned long)&_eshared & PAGE_MASK;
 379         for_each_memblock(memory, reg) {
 380                 start = reg->base;
 381                 end = reg->base + reg->size - 1;
 382                 if (start >= ro_end || end <= ro_start)
 383                         vmem_add_mem(start, end - start, 0);
 384                 else if (start >= ro_start && end <= ro_end)
 385                         vmem_add_mem(start, end - start, 1);
 386                 else if (start >= ro_start) {
 387                         vmem_add_mem(start, ro_end - start, 1);
 388                         vmem_add_mem(ro_end, end - ro_end, 0);
 389                 } else if (end < ro_end) {
 390                         vmem_add_mem(start, ro_start - start, 0);
 391                         vmem_add_mem(ro_start, end - ro_start, 1);
 392                 } else {
 393                         vmem_add_mem(start, ro_start - start, 0);
 394                         vmem_add_mem(ro_start, ro_end - ro_start, 1);
 395                         vmem_add_mem(ro_end, end - ro_end, 0);
 396                 }
 397         }
 398 }
 399
 400 /*
 401  * Convert memblock.memory  to a memory segment list so there is a single
 402  * list that contains all memory segments.
 403  */
 404 static int __init vmem_convert_memory_chunk(void)
 405 {
 406         struct memblock_region *reg;
 407         struct memory_segment *seg;
 408
 409         mutex_lock(&vmem_mutex);
 410         for_each_memblock(memory, reg) {
 411                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 412                 if (!seg)
 413                         panic("Out of memory...\n");
 414                 seg->start = reg->base;
 415                 seg->size = reg->size;
 416                 insert_memory_segment(seg);
 417         }
 418         mutex_unlock(&vmem_mutex);
 419         return 0;
 420 }
 421
 422 core_initcall(vmem_convert_memory_chunk);