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 <asm/pgalloc.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/setup.h>
  16 #include <asm/tlbflush.h>
  17 #include <asm/sections.h>
  18
  19 static DEFINE_MUTEX(vmem_mutex);
  20
  21 struct memory_segment {
  22         struct list_head list;
  23         unsigned long start;
  24         unsigned long size;
  25 };
  26
  27 static LIST_HEAD(mem_segs);
  28
  29 static void __ref *vmem_alloc_pages(unsigned int order)
  30 {
  31         if (slab_is_available())
  32                 return (void *)__get_free_pages(GFP_KERNEL, order);
  33         return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
  34 }
  35
  36 static inline pud_t *vmem_pud_alloc(void)
  37 {
  38         pud_t *pud = NULL;
  39
  40 #ifdef CONFIG_64BIT
  41         pud = vmem_alloc_pages(2);
  42         if (!pud)
  43                 return NULL;
  44         clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
  45 #endif
  46         return pud;
  47 }
  48
  49 static inline pmd_t *vmem_pmd_alloc(void)
  50 {
  51         pmd_t *pmd = NULL;
  52
  53 #ifdef CONFIG_64BIT
  54         pmd = vmem_alloc_pages(2);
  55         if (!pmd)
  56                 return NULL;
  57         clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
  58 #endif
  59         return pmd;
  60 }
  61
  62 static pte_t __ref *vmem_pte_alloc(unsigned long address)
  63 {
  64         pte_t *pte;
  65
  66         if (slab_is_available())
  67                 pte = (pte_t *) page_table_alloc(&init_mm, address);
  68         else
  69                 pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
  70         if (!pte)
  71                 return NULL;
  72         clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
  73                     PTRS_PER_PTE * sizeof(pte_t));
  74         return pte;
  75 }
  76
  77 /*
  78  * Add a physical memory range to the 1:1 mapping.
  79  */
  80 static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
  81 {
  82         unsigned long end = start + size;
  83         unsigned long address = start;
  84         pgd_t *pg_dir;
  85         pud_t *pu_dir;
  86         pmd_t *pm_dir;
  87         pte_t *pt_dir;
  88         pte_t  pte;
  89         int ret = -ENOMEM;
  90
  91         while (address < end) {
  92                 pte = mk_pte_phys(address, __pgprot(ro ? _PAGE_RO : 0));
  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                         pte_val(pte) |= _REGION3_ENTRY_LARGE;
 105                         pte_val(pte) |= _REGION_ENTRY_TYPE_R3;
 106                         pud_val(*pu_dir) = pte_val(pte);
 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                         pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
 122                         pmd_val(*pm_dir) = pte_val(pte);
 123                         address += PMD_SIZE;
 124                         continue;
 125                 }
 126 #endif
 127                 if (pmd_none(*pm_dir)) {
 128                         pt_dir = vmem_pte_alloc(address);
 129                         if (!pt_dir)
 130                                 goto out;
 131                         pmd_populate(&init_mm, pm_dir, pt_dir);
 132                 }
 133
 134                 pt_dir = pte_offset_kernel(pm_dir, address);
 135                 *pt_dir = pte;
 136                 address += PAGE_SIZE;
 137         }
 138         ret = 0;
 139 out:
 140         flush_tlb_kernel_range(start, end);
 141         return ret;
 142 }
 143
 144 /*
 145  * Remove a physical memory range from the 1:1 mapping.
 146  * Currently only invalidates page table entries.
 147  */
 148 static void vmem_remove_range(unsigned long start, unsigned long size)
 149 {
 150         unsigned long end = start + size;
 151         unsigned long address = start;
 152         pgd_t *pg_dir;
 153         pud_t *pu_dir;
 154         pmd_t *pm_dir;
 155         pte_t *pt_dir;
 156         pte_t  pte;
 157
 158         pte_val(pte) = _PAGE_TYPE_EMPTY;
 159         while (address < end) {
 160                 pg_dir = pgd_offset_k(address);
 161                 if (pgd_none(*pg_dir)) {
 162                         address += PGDIR_SIZE;
 163                         continue;
 164                 }
 165                 pu_dir = pud_offset(pg_dir, address);
 166                 if (pud_none(*pu_dir)) {
 167                         address += PUD_SIZE;
 168                         continue;
 169                 }
 170                 if (pud_large(*pu_dir)) {
 171                         pud_clear(pu_dir);
 172                         address += PUD_SIZE;
 173                         continue;
 174                 }
 175                 pm_dir = pmd_offset(pu_dir, address);
 176                 if (pmd_none(*pm_dir)) {
 177                         address += PMD_SIZE;
 178                         continue;
 179                 }
 180                 if (pmd_large(*pm_dir)) {
 181                         pmd_clear(pm_dir);
 182                         address += PMD_SIZE;
 183                         continue;
 184                 }
 185                 pt_dir = pte_offset_kernel(pm_dir, address);
 186                 *pt_dir = pte;
 187                 address += PAGE_SIZE;
 188         }
 189         flush_tlb_kernel_range(start, end);
 190 }
 191
 192 /*
 193  * Add a backed mem_map array to the virtual mem_map array.
 194  */
 195 int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
 196 {
 197         unsigned long address, start_addr, end_addr;
 198         pgd_t *pg_dir;
 199         pud_t *pu_dir;
 200         pmd_t *pm_dir;
 201         pte_t *pt_dir;
 202         pte_t  pte;
 203         int ret = -ENOMEM;
 204
 205         start_addr = (unsigned long) start;
 206         end_addr = (unsigned long) (start + nr);
 207
 208         for (address = start_addr; address < end_addr;) {
 209                 pg_dir = pgd_offset_k(address);
 210                 if (pgd_none(*pg_dir)) {
 211                         pu_dir = vmem_pud_alloc();
 212                         if (!pu_dir)
 213                                 goto out;
 214                         pgd_populate(&init_mm, pg_dir, pu_dir);
 215                 }
 216
 217                 pu_dir = pud_offset(pg_dir, address);
 218                 if (pud_none(*pu_dir)) {
 219                         pm_dir = vmem_pmd_alloc();
 220                         if (!pm_dir)
 221                                 goto out;
 222                         pud_populate(&init_mm, pu_dir, pm_dir);
 223                 }
 224
 225                 pm_dir = pmd_offset(pu_dir, address);
 226                 if (pmd_none(*pm_dir)) {
 227 #ifdef CONFIG_64BIT
 228                         /* Use 1MB frames for vmemmap if available. We always
 229                          * use large frames even if they are only partially
 230                          * used.
 231                          * Otherwise we would have also page tables since
 232                          * vmemmap_populate gets called for each section
 233                          * separately. */
 234                         if (MACHINE_HAS_EDAT1) {
 235                                 void *new_page;
 236
 237                                 new_page = vmemmap_alloc_block(PMD_SIZE, node);
 238                                 if (!new_page)
 239                                         goto out;
 240                                 pte = mk_pte_phys(__pa(new_page), PAGE_RW);
 241                                 pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
 242                                 pmd_val(*pm_dir) = pte_val(pte);
 243                                 address = (address + PMD_SIZE) & PMD_MASK;
 244                                 continue;
 245                         }
 246 #endif
 247                         pt_dir = vmem_pte_alloc(address);
 248                         if (!pt_dir)
 249                                 goto out;
 250                         pmd_populate(&init_mm, pm_dir, pt_dir);
 251                 } else if (pmd_large(*pm_dir)) {
 252                         address = (address + PMD_SIZE) & PMD_MASK;
 253                         continue;
 254                 }
 255
 256                 pt_dir = pte_offset_kernel(pm_dir, address);
 257                 if (pte_none(*pt_dir)) {
 258                         unsigned long new_page;
 259
 260                         new_page =__pa(vmem_alloc_pages(0));
 261                         if (!new_page)
 262                                 goto out;
 263                         pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
 264                         *pt_dir = pte;
 265                 }
 266                 address += PAGE_SIZE;
 267         }
 268         memset(start, 0, nr * sizeof(struct page));
 269         ret = 0;
 270 out:
 271         flush_tlb_kernel_range(start_addr, end_addr);
 272         return ret;
 273 }
 274
 275 /*
 276  * Add memory segment to the segment list if it doesn't overlap with
 277  * an already present segment.
 278  */
 279 static int insert_memory_segment(struct memory_segment *seg)
 280 {
 281         struct memory_segment *tmp;
 282
 283         if (seg->start + seg->size > VMEM_MAX_PHYS ||
 284             seg->start + seg->size < seg->start)
 285                 return -ERANGE;
 286
 287         list_for_each_entry(tmp, &mem_segs, list) {
 288                 if (seg->start >= tmp->start + tmp->size)
 289                         continue;
 290                 if (seg->start + seg->size <= tmp->start)
 291                         continue;
 292                 return -ENOSPC;
 293         }
 294         list_add(&seg->list, &mem_segs);
 295         return 0;
 296 }
 297
 298 /*
 299  * Remove memory segment from the segment list.
 300  */
 301 static void remove_memory_segment(struct memory_segment *seg)
 302 {
 303         list_del(&seg->list);
 304 }
 305
 306 static void __remove_shared_memory(struct memory_segment *seg)
 307 {
 308         remove_memory_segment(seg);
 309         vmem_remove_range(seg->start, seg->size);
 310 }
 311
 312 int vmem_remove_mapping(unsigned long start, unsigned long size)
 313 {
 314         struct memory_segment *seg;
 315         int ret;
 316
 317         mutex_lock(&vmem_mutex);
 318
 319         ret = -ENOENT;
 320         list_for_each_entry(seg, &mem_segs, list) {
 321                 if (seg->start == start && seg->size == size)
 322                         break;
 323         }
 324
 325         if (seg->start != start || seg->size != size)
 326                 goto out;
 327
 328         ret = 0;
 329         __remove_shared_memory(seg);
 330         kfree(seg);
 331 out:
 332         mutex_unlock(&vmem_mutex);
 333         return ret;
 334 }
 335
 336 int vmem_add_mapping(unsigned long start, unsigned long size)
 337 {
 338         struct memory_segment *seg;
 339         int ret;
 340
 341         mutex_lock(&vmem_mutex);
 342         ret = -ENOMEM;
 343         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 344         if (!seg)
 345                 goto out;
 346         seg->start = start;
 347         seg->size = size;
 348
 349         ret = insert_memory_segment(seg);
 350         if (ret)
 351                 goto out_free;
 352
 353         ret = vmem_add_mem(start, size, 0);
 354         if (ret)
 355                 goto out_remove;
 356         goto out;
 357
 358 out_remove:
 359         __remove_shared_memory(seg);
 360 out_free:
 361         kfree(seg);
 362 out:
 363         mutex_unlock(&vmem_mutex);
 364         return ret;
 365 }
 366
 367 /*
 368  * map whole physical memory to virtual memory (identity mapping)
 369  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 370  * additional memory segments.
 371  */
 372 void __init vmem_map_init(void)
 373 {
 374         unsigned long ro_start, ro_end;
 375         unsigned long start, end;
 376         int i;
 377
 378         ro_start = PFN_ALIGN((unsigned long)&_stext);
 379         ro_end = (unsigned long)&_eshared & PAGE_MASK;
 380         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
 381                 if (memory_chunk[i].type == CHUNK_CRASHK ||
 382                     memory_chunk[i].type == CHUNK_OLDMEM)
 383                         continue;
 384                 start = memory_chunk[i].addr;
 385                 end = memory_chunk[i].addr + memory_chunk[i].size;
 386                 if (start >= ro_end || end <= ro_start)
 387                         vmem_add_mem(start, end - start, 0);
 388                 else if (start >= ro_start && end <= ro_end)
 389                         vmem_add_mem(start, end - start, 1);
 390                 else if (start >= ro_start) {
 391                         vmem_add_mem(start, ro_end - start, 1);
 392                         vmem_add_mem(ro_end, end - ro_end, 0);
 393                 } else if (end < ro_end) {
 394                         vmem_add_mem(start, ro_start - start, 0);
 395                         vmem_add_mem(ro_start, end - ro_start, 1);
 396                 } else {
 397                         vmem_add_mem(start, ro_start - start, 0);
 398                         vmem_add_mem(ro_start, ro_end - ro_start, 1);
 399                         vmem_add_mem(ro_end, end - ro_end, 0);
 400                 }
 401         }
 402 }
 403
 404 /*
 405  * Convert memory chunk array to a memory segment list so there is a single
 406  * list that contains both r/w memory and shared memory segments.
 407  */
 408 static int __init vmem_convert_memory_chunk(void)
 409 {
 410         struct memory_segment *seg;
 411         int i;
 412
 413         mutex_lock(&vmem_mutex);
 414         for (i = 0; i < MEMORY_CHUNKS; i++) {
 415                 if (!memory_chunk[i].size)
 416                         continue;
 417                 if (memory_chunk[i].type == CHUNK_CRASHK ||
 418                     memory_chunk[i].type == CHUNK_OLDMEM)
 419                         continue;
 420                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 421                 if (!seg)
 422                         panic("Out of memory...\n");
 423                 seg->start = memory_chunk[i].addr;
 424                 seg->size = memory_chunk[i].size;
 425                 insert_memory_segment(seg);
 426         }
 427         mutex_unlock(&vmem_mutex);
 428         return 0;
 429 }
 430
 431 core_initcall(vmem_convert_memory_chunk);