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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 <linux/hugetlb.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 pud_t *vmem_pud_alloc(void)
  31 {
  32         pud_t *pud = NULL;
  33
  34 #ifdef CONFIG_64BIT
  35         pud = vmemmap_alloc_block(PAGE_SIZE * 4, 0);
  36         if (!pud)
  37                 return NULL;
  38         clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
  39 #endif
  40         return pud;
  41 }
  42
  43 static pmd_t *vmem_pmd_alloc(void)
  44 {
  45         pmd_t *pmd = NULL;
  46
  47 #ifdef CONFIG_64BIT
  48         pmd = vmemmap_alloc_block(PAGE_SIZE * 4, 0);
  49         if (!pmd)
  50                 return NULL;
  51         clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
  52 #endif
  53         return pmd;
  54 }
  55
  56 static pte_t __ref *vmem_pte_alloc(void)
  57 {
  58         pte_t *pte;
  59
  60         if (slab_is_available())
  61                 pte = (pte_t *) page_table_alloc(&init_mm);
  62         else
  63                 pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
  64         if (!pte)
  65                 return NULL;
  66         clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
  67                     PTRS_PER_PTE * sizeof(pte_t));
  68         return pte;
  69 }
  70
  71 /*
  72  * Add a physical memory range to the 1:1 mapping.
  73  */
  74 static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
  75 {
  76         unsigned long address;
  77         pgd_t *pg_dir;
  78         pud_t *pu_dir;
  79         pmd_t *pm_dir;
  80         pte_t *pt_dir;
  81         pte_t  pte;
  82         int ret = -ENOMEM;
  83
  84         for (address = start; address < start + size; address += PAGE_SIZE) {
  85                 pg_dir = pgd_offset_k(address);
  86                 if (pgd_none(*pg_dir)) {
  87                         pu_dir = vmem_pud_alloc();
  88                         if (!pu_dir)
  89                                 goto out;
  90                         pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
  91                 }
  92
  93                 pu_dir = pud_offset(pg_dir, address);
  94                 if (pud_none(*pu_dir)) {
  95                         pm_dir = vmem_pmd_alloc();
  96                         if (!pm_dir)
  97                                 goto out;
  98                         pud_populate_kernel(&init_mm, pu_dir, pm_dir);
  99                 }
 100
 101                 pte = mk_pte_phys(address, __pgprot(ro ? _PAGE_RO : 0));
 102                 pm_dir = pmd_offset(pu_dir, address);
 103
 104 #ifdef __s390x__
 105                 if (MACHINE_HAS_HPAGE && !(address & ~HPAGE_MASK) &&
 106                     (address + HPAGE_SIZE <= start + size) &&
 107                     (address >= HPAGE_SIZE)) {
 108                         pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
 109                         pmd_val(*pm_dir) = pte_val(pte);
 110                         address += HPAGE_SIZE - PAGE_SIZE;
 111                         continue;
 112                 }
 113 #endif
 114                 if (pmd_none(*pm_dir)) {
 115                         pt_dir = vmem_pte_alloc();
 116                         if (!pt_dir)
 117                                 goto out;
 118                         pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
 119                 }
 120
 121                 pt_dir = pte_offset_kernel(pm_dir, address);
 122                 *pt_dir = pte;
 123         }
 124         ret = 0;
 125 out:
 126         flush_tlb_kernel_range(start, start + size);
 127         return ret;
 128 }
 129
 130 /*
 131  * Remove a physical memory range from the 1:1 mapping.
 132  * Currently only invalidates page table entries.
 133  */
 134 static void vmem_remove_range(unsigned long start, unsigned long size)
 135 {
 136         unsigned long address;
 137         pgd_t *pg_dir;
 138         pud_t *pu_dir;
 139         pmd_t *pm_dir;
 140         pte_t *pt_dir;
 141         pte_t  pte;
 142
 143         pte_val(pte) = _PAGE_TYPE_EMPTY;
 144         for (address = start; address < start + size; address += PAGE_SIZE) {
 145                 pg_dir = pgd_offset_k(address);
 146                 pu_dir = pud_offset(pg_dir, address);
 147                 if (pud_none(*pu_dir))
 148                         continue;
 149                 pm_dir = pmd_offset(pu_dir, address);
 150                 if (pmd_none(*pm_dir))
 151                         continue;
 152
 153                 if (pmd_huge(*pm_dir)) {
 154                         pmd_clear_kernel(pm_dir);
 155                         address += HPAGE_SIZE - PAGE_SIZE;
 156                         continue;
 157                 }
 158
 159                 pt_dir = pte_offset_kernel(pm_dir, address);
 160                 *pt_dir = pte;
 161         }
 162         flush_tlb_kernel_range(start, start + size);
 163 }
 164
 165 /*
 166  * Add a backed mem_map array to the virtual mem_map array.
 167  */
 168 int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
 169 {
 170         unsigned long address, start_addr, end_addr;
 171         pgd_t *pg_dir;
 172         pud_t *pu_dir;
 173         pmd_t *pm_dir;
 174         pte_t *pt_dir;
 175         pte_t  pte;
 176         int ret = -ENOMEM;
 177
 178         start_addr = (unsigned long) start;
 179         end_addr = (unsigned long) (start + nr);
 180
 181         for (address = start_addr; address < end_addr; address += PAGE_SIZE) {
 182                 pg_dir = pgd_offset_k(address);
 183                 if (pgd_none(*pg_dir)) {
 184                         pu_dir = vmem_pud_alloc();
 185                         if (!pu_dir)
 186                                 goto out;
 187                         pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
 188                 }
 189
 190                 pu_dir = pud_offset(pg_dir, address);
 191                 if (pud_none(*pu_dir)) {
 192                         pm_dir = vmem_pmd_alloc();
 193                         if (!pm_dir)
 194                                 goto out;
 195                         pud_populate_kernel(&init_mm, pu_dir, pm_dir);
 196                 }
 197
 198                 pm_dir = pmd_offset(pu_dir, address);
 199                 if (pmd_none(*pm_dir)) {
 200                         pt_dir = vmem_pte_alloc();
 201                         if (!pt_dir)
 202                                 goto out;
 203                         pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
 204                 }
 205
 206                 pt_dir = pte_offset_kernel(pm_dir, address);
 207                 if (pte_none(*pt_dir)) {
 208                         unsigned long new_page;
 209
 210                         new_page =__pa(vmemmap_alloc_block(PAGE_SIZE, 0));
 211                         if (!new_page)
 212                                 goto out;
 213                         pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
 214                         *pt_dir = pte;
 215                 }
 216         }
 217         ret = 0;
 218 out:
 219         flush_tlb_kernel_range(start_addr, end_addr);
 220         return ret;
 221 }
 222
 223 /*
 224  * Add memory segment to the segment list if it doesn't overlap with
 225  * an already present segment.
 226  */
 227 static int insert_memory_segment(struct memory_segment *seg)
 228 {
 229         struct memory_segment *tmp;
 230
 231         if (seg->start + seg->size >= VMEM_MAX_PHYS ||
 232             seg->start + seg->size < seg->start)
 233                 return -ERANGE;
 234
 235         list_for_each_entry(tmp, &mem_segs, list) {
 236                 if (seg->start >= tmp->start + tmp->size)
 237                         continue;
 238                 if (seg->start + seg->size <= tmp->start)
 239                         continue;
 240                 return -ENOSPC;
 241         }
 242         list_add(&seg->list, &mem_segs);
 243         return 0;
 244 }
 245
 246 /*
 247  * Remove memory segment from the segment list.
 248  */
 249 static void remove_memory_segment(struct memory_segment *seg)
 250 {
 251         list_del(&seg->list);
 252 }
 253
 254 static void __remove_shared_memory(struct memory_segment *seg)
 255 {
 256         remove_memory_segment(seg);
 257         vmem_remove_range(seg->start, seg->size);
 258 }
 259
 260 int vmem_remove_mapping(unsigned long start, unsigned long size)
 261 {
 262         struct memory_segment *seg;
 263         int ret;
 264
 265         mutex_lock(&vmem_mutex);
 266
 267         ret = -ENOENT;
 268         list_for_each_entry(seg, &mem_segs, list) {
 269                 if (seg->start == start && seg->size == size)
 270                         break;
 271         }
 272
 273         if (seg->start != start || seg->size != size)
 274                 goto out;
 275
 276         ret = 0;
 277         __remove_shared_memory(seg);
 278         kfree(seg);
 279 out:
 280         mutex_unlock(&vmem_mutex);
 281         return ret;
 282 }
 283
 284 int vmem_add_mapping(unsigned long start, unsigned long size)
 285 {
 286         struct memory_segment *seg;
 287         int ret;
 288
 289         mutex_lock(&vmem_mutex);
 290         ret = -ENOMEM;
 291         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 292         if (!seg)
 293                 goto out;
 294         seg->start = start;
 295         seg->size = size;
 296
 297         ret = insert_memory_segment(seg);
 298         if (ret)
 299                 goto out_free;
 300
 301         ret = vmem_add_mem(start, size, 0);
 302         if (ret)
 303                 goto out_remove;
 304         goto out;
 305
 306 out_remove:
 307         __remove_shared_memory(seg);
 308 out_free:
 309         kfree(seg);
 310 out:
 311         mutex_unlock(&vmem_mutex);
 312         return ret;
 313 }
 314
 315 /*
 316  * map whole physical memory to virtual memory (identity mapping)
 317  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 318  * additional memory segments.
 319  */
 320 void __init vmem_map_init(void)
 321 {
 322         unsigned long ro_start, ro_end;
 323         unsigned long start, end;
 324         int i;
 325
 326         INIT_LIST_HEAD(&init_mm.context.crst_list);
 327         INIT_LIST_HEAD(&init_mm.context.pgtable_list);
 328         init_mm.context.noexec = 0;
 329         ro_start = ((unsigned long)&_stext) & PAGE_MASK;
 330         ro_end = PFN_ALIGN((unsigned long)&_eshared);
 331         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
 332                 start = memory_chunk[i].addr;
 333                 end = memory_chunk[i].addr + memory_chunk[i].size;
 334                 if (start >= ro_end || end <= ro_start)
 335                         vmem_add_mem(start, end - start, 0);
 336                 else if (start >= ro_start && end <= ro_end)
 337                         vmem_add_mem(start, end - start, 1);
 338                 else if (start >= ro_start) {
 339                         vmem_add_mem(start, ro_end - start, 1);
 340                         vmem_add_mem(ro_end, end - ro_end, 0);
 341                 } else if (end < ro_end) {
 342                         vmem_add_mem(start, ro_start - start, 0);
 343                         vmem_add_mem(ro_start, end - ro_start, 1);
 344                 } else {
 345                         vmem_add_mem(start, ro_start - start, 0);
 346                         vmem_add_mem(ro_start, ro_end - ro_start, 1);
 347                         vmem_add_mem(ro_end, end - ro_end, 0);
 348                 }
 349         }
 350 }
 351
 352 /*
 353  * Convert memory chunk array to a memory segment list so there is a single
 354  * list that contains both r/w memory and shared memory segments.
 355  */
 356 static int __init vmem_convert_memory_chunk(void)
 357 {
 358         struct memory_segment *seg;
 359         int i;
 360
 361         mutex_lock(&vmem_mutex);
 362         for (i = 0; i < MEMORY_CHUNKS; i++) {
 363                 if (!memory_chunk[i].size)
 364                         continue;
 365                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 366                 if (!seg)
 367                         panic("Out of memory...\n");
 368                 seg->start = memory_chunk[i].addr;
 369                 seg->size = memory_chunk[i].size;
 370                 insert_memory_segment(seg);
 371         }
 372         mutex_unlock(&vmem_mutex);
 373         return 0;
 374 }
 375
 376 core_initcall(vmem_convert_memory_chunk);