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 address;
  83         pgd_t *pg_dir;
  84         pud_t *pu_dir;
  85         pmd_t *pm_dir;
  86         pte_t *pt_dir;
  87         pte_t  pte;
  88         int ret = -ENOMEM;
  89
  90         for (address = start; address < start + size; address += PAGE_SIZE) {
  91                 pg_dir = pgd_offset_k(address);
  92                 if (pgd_none(*pg_dir)) {
  93                         pu_dir = vmem_pud_alloc();
  94                         if (!pu_dir)
  95                                 goto out;
  96                         pgd_populate(&init_mm, pg_dir, pu_dir);
  97                 }
  98
  99                 pu_dir = pud_offset(pg_dir, address);
 100                 if (pud_none(*pu_dir)) {
 101                         pm_dir = vmem_pmd_alloc();
 102                         if (!pm_dir)
 103                                 goto out;
 104                         pud_populate(&init_mm, pu_dir, pm_dir);
 105                 }
 106
 107                 pte = mk_pte_phys(address, __pgprot(ro ? _PAGE_RO : 0));
 108                 pm_dir = pmd_offset(pu_dir, address);
 109
 110 #ifdef CONFIG_64BIT
 111                 if (MACHINE_HAS_HPAGE && !(address & ~HPAGE_MASK) &&
 112                     (address + HPAGE_SIZE <= start + size) &&
 113                     (address >= HPAGE_SIZE)) {
 114                         pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
 115                         pmd_val(*pm_dir) = pte_val(pte);
 116                         address += HPAGE_SIZE - PAGE_SIZE;
 117                         continue;
 118                 }
 119 #endif
 120                 if (pmd_none(*pm_dir)) {
 121                         pt_dir = vmem_pte_alloc(address);
 122                         if (!pt_dir)
 123                                 goto out;
 124                         pmd_populate(&init_mm, pm_dir, pt_dir);
 125                 }
 126
 127                 pt_dir = pte_offset_kernel(pm_dir, address);
 128                 *pt_dir = pte;
 129         }
 130         ret = 0;
 131 out:
 132         flush_tlb_kernel_range(start, start + size);
 133         return ret;
 134 }
 135
 136 /*
 137  * Remove a physical memory range from the 1:1 mapping.
 138  * Currently only invalidates page table entries.
 139  */
 140 static void vmem_remove_range(unsigned long start, unsigned long size)
 141 {
 142         unsigned long address;
 143         pgd_t *pg_dir;
 144         pud_t *pu_dir;
 145         pmd_t *pm_dir;
 146         pte_t *pt_dir;
 147         pte_t  pte;
 148
 149         pte_val(pte) = _PAGE_TYPE_EMPTY;
 150         for (address = start; address < start + size; address += PAGE_SIZE) {
 151                 pg_dir = pgd_offset_k(address);
 152                 pu_dir = pud_offset(pg_dir, address);
 153                 if (pud_none(*pu_dir))
 154                         continue;
 155                 pm_dir = pmd_offset(pu_dir, address);
 156                 if (pmd_none(*pm_dir))
 157                         continue;
 158
 159                 if (pmd_huge(*pm_dir)) {
 160                         pmd_clear(pm_dir);
 161                         address += HPAGE_SIZE - PAGE_SIZE;
 162                         continue;
 163                 }
 164
 165                 pt_dir = pte_offset_kernel(pm_dir, address);
 166                 *pt_dir = pte;
 167         }
 168         flush_tlb_kernel_range(start, start + size);
 169 }
 170
 171 /*
 172  * Add a backed mem_map array to the virtual mem_map array.
 173  */
 174 int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
 175 {
 176         unsigned long address, start_addr, end_addr;
 177         pgd_t *pg_dir;
 178         pud_t *pu_dir;
 179         pmd_t *pm_dir;
 180         pte_t *pt_dir;
 181         pte_t  pte;
 182         int ret = -ENOMEM;
 183
 184         start_addr = (unsigned long) start;
 185         end_addr = (unsigned long) (start + nr);
 186
 187         for (address = start_addr; address < end_addr; address += PAGE_SIZE) {
 188                 pg_dir = pgd_offset_k(address);
 189                 if (pgd_none(*pg_dir)) {
 190                         pu_dir = vmem_pud_alloc();
 191                         if (!pu_dir)
 192                                 goto out;
 193                         pgd_populate(&init_mm, pg_dir, pu_dir);
 194                 }
 195
 196                 pu_dir = pud_offset(pg_dir, address);
 197                 if (pud_none(*pu_dir)) {
 198                         pm_dir = vmem_pmd_alloc();
 199                         if (!pm_dir)
 200                                 goto out;
 201                         pud_populate(&init_mm, pu_dir, pm_dir);
 202                 }
 203
 204                 pm_dir = pmd_offset(pu_dir, address);
 205                 if (pmd_none(*pm_dir)) {
 206                         pt_dir = vmem_pte_alloc(address);
 207                         if (!pt_dir)
 208                                 goto out;
 209                         pmd_populate(&init_mm, pm_dir, pt_dir);
 210                 }
 211
 212                 pt_dir = pte_offset_kernel(pm_dir, address);
 213                 if (pte_none(*pt_dir)) {
 214                         unsigned long new_page;
 215
 216                         new_page =__pa(vmem_alloc_pages(0));
 217                         if (!new_page)
 218                                 goto out;
 219                         pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
 220                         *pt_dir = pte;
 221                 }
 222         }
 223         memset(start, 0, nr * sizeof(struct page));
 224         ret = 0;
 225 out:
 226         flush_tlb_kernel_range(start_addr, end_addr);
 227         return ret;
 228 }
 229
 230 /*
 231  * Add memory segment to the segment list if it doesn't overlap with
 232  * an already present segment.
 233  */
 234 static int insert_memory_segment(struct memory_segment *seg)
 235 {
 236         struct memory_segment *tmp;
 237
 238         if (seg->start + seg->size > VMEM_MAX_PHYS ||
 239             seg->start + seg->size < seg->start)
 240                 return -ERANGE;
 241
 242         list_for_each_entry(tmp, &mem_segs, list) {
 243                 if (seg->start >= tmp->start + tmp->size)
 244                         continue;
 245                 if (seg->start + seg->size <= tmp->start)
 246                         continue;
 247                 return -ENOSPC;
 248         }
 249         list_add(&seg->list, &mem_segs);
 250         return 0;
 251 }
 252
 253 /*
 254  * Remove memory segment from the segment list.
 255  */
 256 static void remove_memory_segment(struct memory_segment *seg)
 257 {
 258         list_del(&seg->list);
 259 }
 260
 261 static void __remove_shared_memory(struct memory_segment *seg)
 262 {
 263         remove_memory_segment(seg);
 264         vmem_remove_range(seg->start, seg->size);
 265 }
 266
 267 int vmem_remove_mapping(unsigned long start, unsigned long size)
 268 {
 269         struct memory_segment *seg;
 270         int ret;
 271
 272         mutex_lock(&vmem_mutex);
 273
 274         ret = -ENOENT;
 275         list_for_each_entry(seg, &mem_segs, list) {
 276                 if (seg->start == start && seg->size == size)
 277                         break;
 278         }
 279
 280         if (seg->start != start || seg->size != size)
 281                 goto out;
 282
 283         ret = 0;
 284         __remove_shared_memory(seg);
 285         kfree(seg);
 286 out:
 287         mutex_unlock(&vmem_mutex);
 288         return ret;
 289 }
 290
 291 int vmem_add_mapping(unsigned long start, unsigned long size)
 292 {
 293         struct memory_segment *seg;
 294         int ret;
 295
 296         mutex_lock(&vmem_mutex);
 297         ret = -ENOMEM;
 298         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 299         if (!seg)
 300                 goto out;
 301         seg->start = start;
 302         seg->size = size;
 303
 304         ret = insert_memory_segment(seg);
 305         if (ret)
 306                 goto out_free;
 307
 308         ret = vmem_add_mem(start, size, 0);
 309         if (ret)
 310                 goto out_remove;
 311         goto out;
 312
 313 out_remove:
 314         __remove_shared_memory(seg);
 315 out_free:
 316         kfree(seg);
 317 out:
 318         mutex_unlock(&vmem_mutex);
 319         return ret;
 320 }
 321
 322 /*
 323  * map whole physical memory to virtual memory (identity mapping)
 324  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 325  * additional memory segments.
 326  */
 327 void __init vmem_map_init(void)
 328 {
 329         unsigned long ro_start, ro_end;
 330         unsigned long start, end;
 331         int i;
 332
 333         ro_start = ((unsigned long)&_stext) & PAGE_MASK;
 334         ro_end = PFN_ALIGN((unsigned long)&_eshared);
 335         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
 336                 if (memory_chunk[i].type == CHUNK_CRASHK ||
 337                     memory_chunk[i].type == CHUNK_OLDMEM)
 338                         continue;
 339                 start = memory_chunk[i].addr;
 340                 end = memory_chunk[i].addr + memory_chunk[i].size;
 341                 if (start >= ro_end || end <= ro_start)
 342                         vmem_add_mem(start, end - start, 0);
 343                 else if (start >= ro_start && end <= ro_end)
 344                         vmem_add_mem(start, end - start, 1);
 345                 else if (start >= ro_start) {
 346                         vmem_add_mem(start, ro_end - start, 1);
 347                         vmem_add_mem(ro_end, end - ro_end, 0);
 348                 } else if (end < ro_end) {
 349                         vmem_add_mem(start, ro_start - start, 0);
 350                         vmem_add_mem(ro_start, end - ro_start, 1);
 351                 } else {
 352                         vmem_add_mem(start, ro_start - start, 0);
 353                         vmem_add_mem(ro_start, ro_end - ro_start, 1);
 354                         vmem_add_mem(ro_end, end - ro_end, 0);
 355                 }
 356         }
 357 }
 358
 359 /*
 360  * Convert memory chunk array to a memory segment list so there is a single
 361  * list that contains both r/w memory and shared memory segments.
 362  */
 363 static int __init vmem_convert_memory_chunk(void)
 364 {
 365         struct memory_segment *seg;
 366         int i;
 367
 368         mutex_lock(&vmem_mutex);
 369         for (i = 0; i < MEMORY_CHUNKS; i++) {
 370                 if (!memory_chunk[i].size)
 371                         continue;
 372                 if (memory_chunk[i].type == CHUNK_CRASHK ||
 373                     memory_chunk[i].type == CHUNK_OLDMEM)
 374                         continue;
 375                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 376                 if (!seg)
 377                         panic("Out of memory...\n");
 378                 seg->start = memory_chunk[i].addr;
 379                 seg->size = memory_chunk[i].size;
 380                 insert_memory_segment(seg);
 381         }
 382         mutex_unlock(&vmem_mutex);
 383         return 0;
 384 }
 385
 386 core_initcall(vmem_convert_memory_chunk);