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   1 /*
   2  *  arch/s390/mm/vmem.c
   3  *
   4  *    Copyright IBM Corp. 2006
   5  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   6  */
   7
   8 #include <linux/bootmem.h>
   9 #include <linux/pfn.h>
  10 #include <linux/mm.h>
  11 #include <linux/module.h>
  12 #include <linux/list.h>
  13 #include <asm/pgalloc.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/setup.h>
  16 #include <asm/tlbflush.h>
  17
  18 static DEFINE_MUTEX(vmem_mutex);
  19
  20 struct memory_segment {
  21         struct list_head list;
  22         unsigned long start;
  23         unsigned long size;
  24 };
  25
  26 static LIST_HEAD(mem_segs);
  27
  28 void __meminit memmap_init(unsigned long size, int nid, unsigned long zone,
  29                            unsigned long start_pfn)
  30 {
  31         struct page *start, *end;
  32         struct page *map_start, *map_end;
  33         int i;
  34
  35         start = pfn_to_page(start_pfn);
  36         end = start + size;
  37
  38         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
  39                 unsigned long cstart, cend;
  40
  41                 cstart = PFN_DOWN(memory_chunk[i].addr);
  42                 cend = cstart + PFN_DOWN(memory_chunk[i].size);
  43
  44                 map_start = mem_map + cstart;
  45                 map_end = mem_map + cend;
  46
  47                 if (map_start < start)
  48                         map_start = start;
  49                 if (map_end > end)
  50                         map_end = end;
  51
  52                 map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1))
  53                         / sizeof(struct page);
  54                 map_end += ((PFN_ALIGN((unsigned long) map_end)
  55                              - (unsigned long) map_end)
  56                             / sizeof(struct page));
  57
  58                 if (map_start < map_end)
  59                         memmap_init_zone((unsigned long)(map_end - map_start),
  60                                          nid, zone, page_to_pfn(map_start),
  61                                          MEMMAP_EARLY);
  62         }
  63 }
  64
  65 static void __ref *vmem_alloc_pages(unsigned int order)
  66 {
  67         if (slab_is_available())
  68                 return (void *)__get_free_pages(GFP_KERNEL, order);
  69         return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
  70 }
  71
  72 static inline pud_t *vmem_pud_alloc(void)
  73 {
  74         pud_t *pud = NULL;
  75
  76 #ifdef CONFIG_64BIT
  77         pud = vmem_alloc_pages(2);
  78         if (!pud)
  79                 return NULL;
  80         pud_val(*pud) = _REGION3_ENTRY_EMPTY;
  81         memcpy(pud + 1, pud, (PTRS_PER_PUD - 1)*sizeof(pud_t));
  82 #endif
  83         return pud;
  84 }
  85
  86 static inline pmd_t *vmem_pmd_alloc(void)
  87 {
  88         pmd_t *pmd = NULL;
  89
  90 #ifdef CONFIG_64BIT
  91         pmd = vmem_alloc_pages(2);
  92         if (!pmd)
  93                 return NULL;
  94         clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE*4);
  95 #endif
  96         return pmd;
  97 }
  98
  99 static pte_t __init_refok *vmem_pte_alloc(void)
 100 {
 101         pte_t *pte;
 102
 103         if (slab_is_available())
 104                 pte = (pte_t *) page_table_alloc(&init_mm);
 105         else
 106                 pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
 107         if (!pte)
 108                 return NULL;
 109         clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
 110                     PTRS_PER_PTE * sizeof(pte_t));
 111         return pte;
 112 }
 113
 114 /*
 115  * Add a physical memory range to the 1:1 mapping.
 116  */
 117 static int vmem_add_range(unsigned long start, unsigned long size)
 118 {
 119         unsigned long address;
 120         pgd_t *pg_dir;
 121         pud_t *pu_dir;
 122         pmd_t *pm_dir;
 123         pte_t *pt_dir;
 124         pte_t  pte;
 125         int ret = -ENOMEM;
 126
 127         for (address = start; address < start + size; address += PAGE_SIZE) {
 128                 pg_dir = pgd_offset_k(address);
 129                 if (pgd_none(*pg_dir)) {
 130                         pu_dir = vmem_pud_alloc();
 131                         if (!pu_dir)
 132                                 goto out;
 133                         pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
 134                 }
 135
 136                 pu_dir = pud_offset(pg_dir, address);
 137                 if (pud_none(*pu_dir)) {
 138                         pm_dir = vmem_pmd_alloc();
 139                         if (!pm_dir)
 140                                 goto out;
 141                         pud_populate_kernel(&init_mm, pu_dir, pm_dir);
 142                 }
 143
 144                 pm_dir = pmd_offset(pu_dir, address);
 145                 if (pmd_none(*pm_dir)) {
 146                         pt_dir = vmem_pte_alloc();
 147                         if (!pt_dir)
 148                                 goto out;
 149                         pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
 150                 }
 151
 152                 pt_dir = pte_offset_kernel(pm_dir, address);
 153                 pte = pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL);
 154                 *pt_dir = pte;
 155         }
 156         ret = 0;
 157 out:
 158         flush_tlb_kernel_range(start, start + size);
 159         return ret;
 160 }
 161
 162 /*
 163  * Remove a physical memory range from the 1:1 mapping.
 164  * Currently only invalidates page table entries.
 165  */
 166 static void vmem_remove_range(unsigned long start, unsigned long size)
 167 {
 168         unsigned long address;
 169         pgd_t *pg_dir;
 170         pud_t *pu_dir;
 171         pmd_t *pm_dir;
 172         pte_t *pt_dir;
 173         pte_t  pte;
 174
 175         pte_val(pte) = _PAGE_TYPE_EMPTY;
 176         for (address = start; address < start + size; address += PAGE_SIZE) {
 177                 pg_dir = pgd_offset_k(address);
 178                 pu_dir = pud_offset(pg_dir, address);
 179                 if (pud_none(*pu_dir))
 180                         continue;
 181                 pm_dir = pmd_offset(pu_dir, address);
 182                 if (pmd_none(*pm_dir))
 183                         continue;
 184                 pt_dir = pte_offset_kernel(pm_dir, address);
 185                 *pt_dir = pte;
 186         }
 187         flush_tlb_kernel_range(start, start + size);
 188 }
 189
 190 /*
 191  * Add a backed mem_map array to the virtual mem_map array.
 192  */
 193 static int vmem_add_mem_map(unsigned long start, unsigned long size)
 194 {
 195         unsigned long address, start_addr, end_addr;
 196         struct page *map_start, *map_end;
 197         pgd_t *pg_dir;
 198         pud_t *pu_dir;
 199         pmd_t *pm_dir;
 200         pte_t *pt_dir;
 201         pte_t  pte;
 202         int ret = -ENOMEM;
 203
 204         map_start = VMEM_MAP + PFN_DOWN(start);
 205         map_end = VMEM_MAP + PFN_DOWN(start + size);
 206
 207         start_addr = (unsigned long) map_start & PAGE_MASK;
 208         end_addr = PFN_ALIGN((unsigned long) map_end);
 209
 210         for (address = start_addr; address < end_addr; address += PAGE_SIZE) {
 211                 pg_dir = pgd_offset_k(address);
 212                 if (pgd_none(*pg_dir)) {
 213                         pu_dir = vmem_pud_alloc();
 214                         if (!pu_dir)
 215                                 goto out;
 216                         pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
 217                 }
 218
 219                 pu_dir = pud_offset(pg_dir, address);
 220                 if (pud_none(*pu_dir)) {
 221                         pm_dir = vmem_pmd_alloc();
 222                         if (!pm_dir)
 223                                 goto out;
 224                         pud_populate_kernel(&init_mm, pu_dir, pm_dir);
 225                 }
 226
 227                 pm_dir = pmd_offset(pu_dir, address);
 228                 if (pmd_none(*pm_dir)) {
 229                         pt_dir = vmem_pte_alloc();
 230                         if (!pt_dir)
 231                                 goto out;
 232                         pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
 233                 }
 234
 235                 pt_dir = pte_offset_kernel(pm_dir, address);
 236                 if (pte_none(*pt_dir)) {
 237                         unsigned long new_page;
 238
 239                         new_page =__pa(vmem_alloc_pages(0));
 240                         if (!new_page)
 241                                 goto out;
 242                         pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
 243                         *pt_dir = pte;
 244                 }
 245         }
 246         ret = 0;
 247 out:
 248         flush_tlb_kernel_range(start_addr, end_addr);
 249         return ret;
 250 }
 251
 252 static int vmem_add_mem(unsigned long start, unsigned long size)
 253 {
 254         int ret;
 255
 256         ret = vmem_add_mem_map(start, size);
 257         if (ret)
 258                 return ret;
 259         return vmem_add_range(start, size);
 260 }
 261
 262 /*
 263  * Add memory segment to the segment list if it doesn't overlap with
 264  * an already present segment.
 265  */
 266 static int insert_memory_segment(struct memory_segment *seg)
 267 {
 268         struct memory_segment *tmp;
 269
 270         if (seg->start + seg->size >= VMEM_MAX_PHYS ||
 271             seg->start + seg->size < seg->start)
 272                 return -ERANGE;
 273
 274         list_for_each_entry(tmp, &mem_segs, list) {
 275                 if (seg->start >= tmp->start + tmp->size)
 276                         continue;
 277                 if (seg->start + seg->size <= tmp->start)
 278                         continue;
 279                 return -ENOSPC;
 280         }
 281         list_add(&seg->list, &mem_segs);
 282         return 0;
 283 }
 284
 285 /*
 286  * Remove memory segment from the segment list.
 287  */
 288 static void remove_memory_segment(struct memory_segment *seg)
 289 {
 290         list_del(&seg->list);
 291 }
 292
 293 static void __remove_shared_memory(struct memory_segment *seg)
 294 {
 295         remove_memory_segment(seg);
 296         vmem_remove_range(seg->start, seg->size);
 297 }
 298
 299 int remove_shared_memory(unsigned long start, unsigned long size)
 300 {
 301         struct memory_segment *seg;
 302         int ret;
 303
 304         mutex_lock(&vmem_mutex);
 305
 306         ret = -ENOENT;
 307         list_for_each_entry(seg, &mem_segs, list) {
 308                 if (seg->start == start && seg->size == size)
 309                         break;
 310         }
 311
 312         if (seg->start != start || seg->size != size)
 313                 goto out;
 314
 315         ret = 0;
 316         __remove_shared_memory(seg);
 317         kfree(seg);
 318 out:
 319         mutex_unlock(&vmem_mutex);
 320         return ret;
 321 }
 322
 323 int add_shared_memory(unsigned long start, unsigned long size)
 324 {
 325         struct memory_segment *seg;
 326         struct page *page;
 327         unsigned long pfn, num_pfn, end_pfn;
 328         int ret;
 329
 330         mutex_lock(&vmem_mutex);
 331         ret = -ENOMEM;
 332         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 333         if (!seg)
 334                 goto out;
 335         seg->start = start;
 336         seg->size = size;
 337
 338         ret = insert_memory_segment(seg);
 339         if (ret)
 340                 goto out_free;
 341
 342         ret = vmem_add_mem(start, size);
 343         if (ret)
 344                 goto out_remove;
 345
 346         pfn = PFN_DOWN(start);
 347         num_pfn = PFN_DOWN(size);
 348         end_pfn = pfn + num_pfn;
 349
 350         page = pfn_to_page(pfn);
 351         memset(page, 0, num_pfn * sizeof(struct page));
 352
 353         for (; pfn < end_pfn; pfn++) {
 354                 page = pfn_to_page(pfn);
 355                 init_page_count(page);
 356                 reset_page_mapcount(page);
 357                 SetPageReserved(page);
 358                 INIT_LIST_HEAD(&page->lru);
 359         }
 360         goto out;
 361
 362 out_remove:
 363         __remove_shared_memory(seg);
 364 out_free:
 365         kfree(seg);
 366 out:
 367         mutex_unlock(&vmem_mutex);
 368         return ret;
 369 }
 370
 371 /*
 372  * map whole physical memory to virtual memory (identity mapping)
 373  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 374  * additional memory segments.
 375  */
 376 void __init vmem_map_init(void)
 377 {
 378         int i;
 379
 380         INIT_LIST_HEAD(&init_mm.context.crst_list);
 381         INIT_LIST_HEAD(&init_mm.context.pgtable_list);
 382         init_mm.context.noexec = 0;
 383         NODE_DATA(0)->node_mem_map = VMEM_MAP;
 384         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++)
 385                 vmem_add_mem(memory_chunk[i].addr, memory_chunk[i].size);
 386 }
 387
 388 /*
 389  * Convert memory chunk array to a memory segment list so there is a single
 390  * list that contains both r/w memory and shared memory segments.
 391  */
 392 static int __init vmem_convert_memory_chunk(void)
 393 {
 394         struct memory_segment *seg;
 395         int i;
 396
 397         mutex_lock(&vmem_mutex);
 398         for (i = 0; i < MEMORY_CHUNKS; i++) {
 399                 if (!memory_chunk[i].size)
 400                         continue;
 401                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 402                 if (!seg)
 403                         panic("Out of memory...\n");
 404                 seg->start = memory_chunk[i].addr;
 405                 seg->size = memory_chunk[i].size;
 406                 insert_memory_segment(seg);
 407         }
 408         mutex_unlock(&vmem_mutex);
 409         return 0;
 410 }
 411
 412 core_initcall(vmem_convert_memory_chunk);