linux/arch/s390/mm/vmem.c
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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
  20static DEFINE_MUTEX(vmem_mutex);
  21
  22struct memory_segment {
  23        struct list_head list;
  24        unsigned long start;
  25        unsigned long size;
  26};
  27
  28static LIST_HEAD(mem_segs);
  29
  30static 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
  37static 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
  50static 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
  63static pte_t __ref *vmem_pte_alloc(void)
  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(PTRS_PER_PTE * sizeof(pte_t));
  71        if (!pte)
  72                return NULL;
  73        clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
  74                    PTRS_PER_PTE * sizeof(pte_t));
  75        return pte;
  76}
  77
  78/*
  79 * Add a physical memory range to the 1:1 mapping.
  80 */
  81static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
  82{
  83        unsigned long address;
  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        for (address = start; address < start + size; address += PAGE_SIZE) {
  92                pg_dir = pgd_offset_k(address);
  93                if (pgd_none(*pg_dir)) {
  94                        pu_dir = vmem_pud_alloc();
  95                        if (!pu_dir)
  96                                goto out;
  97                        pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
  98                }
  99
 100                pu_dir = pud_offset(pg_dir, address);
 101                if (pud_none(*pu_dir)) {
 102                        pm_dir = vmem_pmd_alloc();
 103                        if (!pm_dir)
 104                                goto out;
 105                        pud_populate_kernel(&init_mm, pu_dir, pm_dir);
 106                }
 107
 108                pte = mk_pte_phys(address, __pgprot(ro ? _PAGE_RO : 0));
 109                pm_dir = pmd_offset(pu_dir, address);
 110
 111#ifdef __s390x__
 112                if (MACHINE_HAS_HPAGE && !(address & ~HPAGE_MASK) &&
 113                    (address + HPAGE_SIZE <= start + size) &&
 114                    (address >= HPAGE_SIZE)) {
 115                        pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
 116                        pmd_val(*pm_dir) = pte_val(pte);
 117                        address += HPAGE_SIZE - PAGE_SIZE;
 118                        continue;
 119                }
 120#endif
 121                if (pmd_none(*pm_dir)) {
 122                        pt_dir = vmem_pte_alloc();
 123                        if (!pt_dir)
 124                                goto out;
 125                        pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
 126                }
 127
 128                pt_dir = pte_offset_kernel(pm_dir, address);
 129                *pt_dir = pte;
 130        }
 131        ret = 0;
 132out:
 133        flush_tlb_kernel_range(start, start + size);
 134        return ret;
 135}
 136
 137/*
 138 * Remove a physical memory range from the 1:1 mapping.
 139 * Currently only invalidates page table entries.
 140 */
 141static void vmem_remove_range(unsigned long start, unsigned long size)
 142{
 143        unsigned long address;
 144        pgd_t *pg_dir;
 145        pud_t *pu_dir;
 146        pmd_t *pm_dir;
 147        pte_t *pt_dir;
 148        pte_t  pte;
 149
 150        pte_val(pte) = _PAGE_TYPE_EMPTY;
 151        for (address = start; address < start + size; address += PAGE_SIZE) {
 152                pg_dir = pgd_offset_k(address);
 153                pu_dir = pud_offset(pg_dir, address);
 154                if (pud_none(*pu_dir))
 155                        continue;
 156                pm_dir = pmd_offset(pu_dir, address);
 157                if (pmd_none(*pm_dir))
 158                        continue;
 159
 160                if (pmd_huge(*pm_dir)) {
 161                        pmd_clear_kernel(pm_dir);
 162                        address += HPAGE_SIZE - PAGE_SIZE;
 163                        continue;
 164                }
 165
 166                pt_dir = pte_offset_kernel(pm_dir, address);
 167                *pt_dir = pte;
 168        }
 169        flush_tlb_kernel_range(start, start + size);
 170}
 171
 172/*
 173 * Add a backed mem_map array to the virtual mem_map array.
 174 */
 175int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
 176{
 177        unsigned long address, start_addr, end_addr;
 178        pgd_t *pg_dir;
 179        pud_t *pu_dir;
 180        pmd_t *pm_dir;
 181        pte_t *pt_dir;
 182        pte_t  pte;
 183        int ret = -ENOMEM;
 184
 185        start_addr = (unsigned long) start;
 186        end_addr = (unsigned long) (start + nr);
 187
 188        for (address = start_addr; address < end_addr; address += PAGE_SIZE) {
 189                pg_dir = pgd_offset_k(address);
 190                if (pgd_none(*pg_dir)) {
 191                        pu_dir = vmem_pud_alloc();
 192                        if (!pu_dir)
 193                                goto out;
 194                        pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
 195                }
 196
 197                pu_dir = pud_offset(pg_dir, address);
 198                if (pud_none(*pu_dir)) {
 199                        pm_dir = vmem_pmd_alloc();
 200                        if (!pm_dir)
 201                                goto out;
 202                        pud_populate_kernel(&init_mm, pu_dir, pm_dir);
 203                }
 204
 205                pm_dir = pmd_offset(pu_dir, address);
 206                if (pmd_none(*pm_dir)) {
 207                        pt_dir = vmem_pte_alloc();
 208                        if (!pt_dir)
 209                                goto out;
 210                        pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
 211                }
 212
 213                pt_dir = pte_offset_kernel(pm_dir, address);
 214                if (pte_none(*pt_dir)) {
 215                        unsigned long new_page;
 216
 217                        new_page =__pa(vmem_alloc_pages(0));
 218                        if (!new_page)
 219                                goto out;
 220                        pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
 221                        *pt_dir = pte;
 222                }
 223        }
 224        memset(start, 0, nr * sizeof(struct page));
 225        ret = 0;
 226out:
 227        flush_tlb_kernel_range(start_addr, end_addr);
 228        return ret;
 229}
 230
 231/*
 232 * Add memory segment to the segment list if it doesn't overlap with
 233 * an already present segment.
 234 */
 235static int insert_memory_segment(struct memory_segment *seg)
 236{
 237        struct memory_segment *tmp;
 238
 239        if (seg->start + seg->size > VMEM_MAX_PHYS ||
 240            seg->start + seg->size < seg->start)
 241                return -ERANGE;
 242
 243        list_for_each_entry(tmp, &mem_segs, list) {
 244                if (seg->start >= tmp->start + tmp->size)
 245                        continue;
 246                if (seg->start + seg->size <= tmp->start)
 247                        continue;
 248                return -ENOSPC;
 249        }
 250        list_add(&seg->list, &mem_segs);
 251        return 0;
 252}
 253
 254/*
 255 * Remove memory segment from the segment list.
 256 */
 257static void remove_memory_segment(struct memory_segment *seg)
 258{
 259        list_del(&seg->list);
 260}
 261
 262static void __remove_shared_memory(struct memory_segment *seg)
 263{
 264        remove_memory_segment(seg);
 265        vmem_remove_range(seg->start, seg->size);
 266}
 267
 268int vmem_remove_mapping(unsigned long start, unsigned long size)
 269{
 270        struct memory_segment *seg;
 271        int ret;
 272
 273        mutex_lock(&vmem_mutex);
 274
 275        ret = -ENOENT;
 276        list_for_each_entry(seg, &mem_segs, list) {
 277                if (seg->start == start && seg->size == size)
 278                        break;
 279        }
 280
 281        if (seg->start != start || seg->size != size)
 282                goto out;
 283
 284        ret = 0;
 285        __remove_shared_memory(seg);
 286        kfree(seg);
 287out:
 288        mutex_unlock(&vmem_mutex);
 289        return ret;
 290}
 291
 292int vmem_add_mapping(unsigned long start, unsigned long size)
 293{
 294        struct memory_segment *seg;
 295        int ret;
 296
 297        mutex_lock(&vmem_mutex);
 298        ret = -ENOMEM;
 299        seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 300        if (!seg)
 301                goto out;
 302        seg->start = start;
 303        seg->size = size;
 304
 305        ret = insert_memory_segment(seg);
 306        if (ret)
 307                goto out_free;
 308
 309        ret = vmem_add_mem(start, size, 0);
 310        if (ret)
 311                goto out_remove;
 312        goto out;
 313
 314out_remove:
 315        __remove_shared_memory(seg);
 316out_free:
 317        kfree(seg);
 318out:
 319        mutex_unlock(&vmem_mutex);
 320        return ret;
 321}
 322
 323/*
 324 * map whole physical memory to virtual memory (identity mapping)
 325 * we reserve enough space in the vmalloc area for vmemmap to hotplug
 326 * additional memory segments.
 327 */
 328void __init vmem_map_init(void)
 329{
 330        unsigned long ro_start, ro_end;
 331        unsigned long start, end;
 332        int i;
 333
 334        INIT_LIST_HEAD(&init_mm.context.crst_list);
 335        INIT_LIST_HEAD(&init_mm.context.pgtable_list);
 336        init_mm.context.noexec = 0;
 337        ro_start = ((unsigned long)&_stext) & PAGE_MASK;
 338        ro_end = PFN_ALIGN((unsigned long)&_eshared);
 339        for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
 340                start = memory_chunk[i].addr;
 341                end = memory_chunk[i].addr + memory_chunk[i].size;
 342                if (start >= ro_end || end <= ro_start)
 343                        vmem_add_mem(start, end - start, 0);
 344                else if (start >= ro_start && end <= ro_end)
 345                        vmem_add_mem(start, end - start, 1);
 346                else if (start >= ro_start) {
 347                        vmem_add_mem(start, ro_end - start, 1);
 348                        vmem_add_mem(ro_end, end - ro_end, 0);
 349                } else if (end < ro_end) {
 350                        vmem_add_mem(start, ro_start - start, 0);
 351                        vmem_add_mem(ro_start, end - ro_start, 1);
 352                } else {
 353                        vmem_add_mem(start, ro_start - start, 0);
 354                        vmem_add_mem(ro_start, ro_end - ro_start, 1);
 355                        vmem_add_mem(ro_end, end - ro_end, 0);
 356                }
 357        }
 358}
 359
 360/*
 361 * Convert memory chunk array to a memory segment list so there is a single
 362 * list that contains both r/w memory and shared memory segments.
 363 */
 364static int __init vmem_convert_memory_chunk(void)
 365{
 366        struct memory_segment *seg;
 367        int i;
 368
 369        mutex_lock(&vmem_mutex);
 370        for (i = 0; i < MEMORY_CHUNKS; i++) {
 371                if (!memory_chunk[i].size)
 372                        continue;
 373                seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 374                if (!seg)
 375                        panic("Out of memory...\n");
 376                seg->start = memory_chunk[i].addr;
 377                seg->size = memory_chunk[i].size;
 378                insert_memory_segment(seg);
 379        }
 380        mutex_unlock(&vmem_mutex);
 381        return 0;
 382}
 383
 384core_initcall(vmem_convert_memory_chunk);
 385