arch/s390x/mm/init.c

   1 /*
   2  *  arch/s390/mm/init.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Hartmut Penner (hpenner@de.ibm.com)
   7  *
   8  *  Derived from "arch/i386/mm/init.c"
   9  *    Copyright (C) 1995  Linus Torvalds
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/signal.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/string.h>
  18 #include <linux/types.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/mman.h>
  21 #include <linux/mm.h>
  22 #include <linux/swap.h>
  23 #include <linux/smp.h>
  24 #include <linux/init.h>
  25 #ifdef CONFIG_BLK_DEV_INITRD
  26 #include <linux/blk.h>
  27 #endif
  28 #include <linux/pagemap.h>
  29 #include <linux/bootmem.h>
  30
  31 #include <asm/processor.h>
  32 #include <asm/system.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/pgalloc.h>
  36 #include <asm/dma.h>
  37 #include <asm/lowcore.h>
  38 #include <asm/tlb.h>
  39
  40 mmu_gather_t mmu_gathers[NR_CPUS];
  41
  42 static unsigned long totalram_pages;
  43 extern unsigned long memory_size;
  44
  45 pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
  46 char  empty_zero_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  47
  48 static inline int
  49 __pgd_populate(unsigned long *pgd_slot, unsigned long offset, pmd_t *pmd)
  50 {
  51         if (offset == 0 &&
  52             ((*pgd_slot & _PGD_ENTRY_INV) != 0 ||
  53              (*pgd_slot & _PGD_ENTRY_LEN(2)) == 0)) {
  54                 /* Set lower pmd, upper pmd is empty. */
  55                 *pgd_slot = __pa(pmd) | _PGD_ENTRY_MASK |
  56                                 _PGD_ENTRY_OFF(0) | _PGD_ENTRY_LEN(1);
  57                 return 1;
  58         }
  59         if (offset == 4 &&
  60             ((*pgd_slot & _PGD_ENTRY_INV) != 0 ||
  61              (*pgd_slot & _PGD_ENTRY_OFF(2)) != 0)) {
  62                 /* Lower pmd empty, set upper pmd. */
  63                 *pgd_slot = (__pa(pmd) - 0x2000) | _PGD_ENTRY_MASK |
  64                                 _PGD_ENTRY_OFF(2) | _PGD_ENTRY_LEN(3);
  65                 return 1;
  66         }
  67         return 0;
  68 }
  69
  70 pmd_t *pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
  71 {
  72         unsigned long addr = (unsigned long) pgd;
  73         unsigned long *pgd_slot =  (unsigned long *) (addr & -8);
  74         unsigned long offset = addr & 4;
  75         pmd_t *new, *pmd2;
  76         int i;
  77
  78         /* Check if we can get away with a half-sized pmd. */
  79         if (__pgd_populate(pgd_slot, offset, pmd))
  80                 return pmd;
  81
  82         /* We have to enlarge the pmd to 16K if we arrive here. */
  83         spin_unlock(&mm->page_table_lock);
  84         new = (pmd_t *) __get_free_pages(GFP_KERNEL, 2);
  85         spin_lock(&mm->page_table_lock);
  86
  87         /*
  88          * Because we dropped the lock, we should re-check the
  89          * entry, as somebody else could have populated it..
  90          */
  91         if (!pgd_none(*pgd)) {
  92                 if (new)
  93                         free_pages((unsigned long) new, 2);
  94                 pmd_free(pmd);
  95                 return (pmd_t *) pgd_val(*pgd);
  96         }
  97
  98         if (!new) {
  99                 pmd_free(pmd);
 100                 return NULL;
 101         }
 102
 103         /*
 104          * Re-check if we can get away with a half-sized pmd. We
 105          * dropped the lock so somebody else could have freed the
 106          * other half of the pmd.
 107          */
 108         if (__pgd_populate(pgd_slot, offset, pmd)) {
 109                 free_pages((unsigned long) new, 2);
 110                 return pmd;
 111         }
 112
 113         /* Set the PG_arch_1 bit on the first and the third pmd page
 114            so that pmd_free_fast can recognize pmds that have been
 115            allocated with an order 2 allocation.  */
 116         set_bit(PG_arch_1, &virt_to_page(new)->flags);
 117         set_bit(PG_arch_1, &virt_to_page(new+PTRS_PER_PMD)->flags);
 118         /* Now copy the two pmds to the new memory area. */
 119         if (offset == 0) {
 120                 pmd2 = (pmd_t *)(*pgd_slot & PAGE_MASK) + PTRS_PER_PMD;
 121                 memcpy(new, pmd, sizeof(pmd_t)*PTRS_PER_PMD);
 122                 memcpy(new + PTRS_PER_PMD, pmd2, sizeof(pmd_t)*PTRS_PER_PMD);
 123         } else {
 124                 pmd2 = (pmd_t *)(*pgd_slot & PAGE_MASK);
 125                 memcpy(new, pmd2, sizeof(pmd_t)*PTRS_PER_PMD);
 126                 memcpy(new + PTRS_PER_PMD, pmd, sizeof(pmd_t)*PTRS_PER_PMD);
 127         }
 128         *pgd_slot = __pa(new) | _PGD_ENTRY_MASK |
 129                         _PGD_ENTRY_OFF(0) | _PGD_ENTRY_LEN(3);
 130         for (i = 0; i < PTRS_PER_PMD; i++) {
 131                 pmd_clear(pmd + i);
 132                 pmd_clear(pmd2 + i);
 133         }
 134         pmd_free(pmd);
 135         pmd_free(pmd2);
 136         return new;
 137 }
 138
 139 void pmd_free_order2(pmd_t *pmd)
 140 {
 141         pmd_t *pmd2 = (pmd_t *) ((unsigned long) pmd ^ 8192);
 142
 143         clear_bit(PG_arch_1, &virt_to_page(pmd)->flags);
 144         if (test_bit(PG_arch_1, &virt_to_page(pmd2)->flags) == 0) {
 145                 /* The other pmd of the order 2 allocation has already
 146                    been freed. Now we can release the order 2 allocation.  */
 147                 free_pages((unsigned long) pmd & ~8192, 2);
 148         }
 149 }
 150
 151 int do_check_pgt_cache(int low, int high)
 152 {
 153         int freed = 0;
 154         if(pgtable_cache_size > high) {
 155                 do {
 156                         if(pgd_quicklist) {
 157                                 free_pgd_slow(get_pgd_fast());
 158                                 freed += 2;
 159                         }
 160                         if(pmd_quicklist) {
 161                                 pmd_free_slow(pmd_alloc_one_fast(NULL, 0));
 162                                 freed += 2;
 163                         }
 164                         if(pte_quicklist) {
 165                                 pte_free_slow(pte_alloc_one_fast(NULL, 0));
 166                                 freed += 1;
 167                         }
 168                 } while(pgtable_cache_size > low);
 169         }
 170         return freed;
 171 }
 172
 173 void diag10(unsigned long addr)
 174 {
 175         if (addr >= 0x80000000)
 176                 return;
 177         asm volatile ("sam31\n\t"
 178                       "diag %0,%0,0x10\n\t"
 179                       "sam64" : : "a" (addr) );
 180 }
 181
 182 void show_mem(void)
 183 {
 184         int i, total = 0,reserved = 0;
 185         int shared = 0, cached = 0;
 186
 187         printk("Mem-info:\n");
 188         show_free_areas();
 189         printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
 190         i = max_mapnr;
 191         while (i-- > 0) {
 192                 total++;
 193                 if (PageReserved(mem_map+i))
 194                         reserved++;
 195                 else if (PageSwapCache(mem_map+i))
 196                         cached++;
 197                 else if (page_count(mem_map+i))
 198                         shared += atomic_read(&mem_map[i].count) - 1;
 199         }
 200         printk("%d pages of RAM\n",total);
 201         printk("%d reserved pages\n",reserved);
 202         printk("%d pages shared\n",shared);
 203         printk("%d pages swap cached\n",cached);
 204         printk("%ld pages in page table cache\n",pgtable_cache_size);
 205         show_buffers();
 206 }
 207
 208 /* References to section boundaries */
 209
 210 extern unsigned long _text;
 211 extern unsigned long _etext;
 212 extern unsigned long _edata;
 213 extern unsigned long __bss_start;
 214 extern unsigned long _end;
 215
 216 extern unsigned long __init_begin;
 217 extern unsigned long __init_end;
 218
 219 /*
 220  * paging_init() sets up the page tables
 221  */
 222
 223 unsigned long last_valid_pfn;
 224
 225 void __init paging_init(void)
 226 {
 227         unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
 228         static const int ssm_mask = 0x04000000L;
 229         unsigned long dma_pfn, address, end_mem;
 230         pgd_t * pg_dir;
 231         int     i,j,k;
 232
 233         dma_pfn = MAX_DMA_ADDRESS >> PAGE_SHIFT;
 234
 235         if (dma_pfn > max_low_pfn)
 236                 zones_size[ZONE_DMA] = max_low_pfn;
 237         else {
 238                 zones_size[ZONE_DMA] = dma_pfn;
 239                 zones_size[ZONE_NORMAL] = max_low_pfn - dma_pfn;
 240         }
 241
 242         /* Initialize mem_map[].  */
 243         free_area_init(zones_size);
 244
 245         /*
 246          * map whole physical memory to virtual memory (identity mapping)
 247          */
 248         pg_dir = swapper_pg_dir;
 249         address = 0;
 250         end_mem = (unsigned long) __va(max_low_pfn*PAGE_SIZE);
 251         for (i = 0 ; i < PTRS_PER_PGD/2 ; i++, pg_dir += 2) {
 252                 pmd_t *pm_dir;
 253
 254                 if (address >= end_mem) {
 255                         pgd_clear(pg_dir);
 256                         continue;
 257                 }
 258
 259                 pm_dir = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE*4);
 260                 *((unsigned long *) pg_dir) = __pa(pm_dir) | _PGD_ENTRY_MASK |
 261                         _PGD_ENTRY_LEN(3) | _PGD_ENTRY_OFF(0);
 262
 263                 for (j = 0 ; j < PTRS_PER_PMD*2 ; j++, pm_dir++) {
 264                         pte_t *pt_dir;
 265
 266                         if (address >= end_mem) {
 267                                 pmd_clear(pm_dir);
 268                                 continue;
 269                         }
 270
 271                         pt_dir = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 272                         pmd_populate(&init_mm, pm_dir, pt_dir);
 273
 274                         for (k = 0 ; k < PTRS_PER_PTE ; k++,pt_dir++) {
 275                                 pte_t pte = mk_pte_phys(address, PAGE_KERNEL);
 276                                 if (address >= end_mem) {
 277                                         pte_clear(&pte);
 278                                         continue;
 279                                 }
 280                                 set_pte(pt_dir, pte);
 281                                 address += PAGE_SIZE;
 282                         }
 283                 }
 284         }
 285
 286         /* enable virtual mapping in kernel mode */
 287         __asm__ __volatile__("lctlg 1,1,%0\n\t"
 288                              "lctlg 7,7,%0\n\t"
 289                              "lctlg 13,13,%0\n\t"
 290                              "ssm   %1"
 291                              : :"m" (__pa(swapper_pg_dir) | _KERN_REGION_TABLE),
 292                                 "m" (ssm_mask));
 293         local_flush_tlb();
 294
 295         return;
 296 }
 297
 298 void __init mem_init(void)
 299 {
 300         unsigned long codesize, reservedpages, datasize, initsize;
 301
 302         max_mapnr = num_physpages = max_low_pfn;
 303         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 304
 305         /* clear the zero-page */
 306         memset(empty_zero_page, 0, PAGE_SIZE);
 307
 308         /* this will put all low memory onto the freelists */
 309         totalram_pages += free_all_bootmem();
 310
 311         reservedpages = 0;
 312
 313         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 314         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 315         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 316         printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, %ldk data, %ldk init)\n",
 317                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 318                 max_mapnr << (PAGE_SHIFT-10),
 319                 codesize >> 10,
 320                 reservedpages << (PAGE_SHIFT-10),
 321                 datasize >>10,
 322                 initsize >> 10);
 323 }
 324
 325 void free_initmem(void)
 326 {
 327         unsigned long addr;
 328
 329         addr = (unsigned long)(&__init_begin);
 330         for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 331                 ClearPageReserved(virt_to_page(addr));
 332                 set_page_count(virt_to_page(addr), 1);
 333                 free_page(addr);
 334                 totalram_pages++;
 335         }
 336         printk (KERN_INFO "Freeing unused kernel memory: %ldk freed\n",
 337                 (&__init_end - &__init_begin) >> 10);
 338 }
 339
 340 #ifdef CONFIG_BLK_DEV_INITRD
 341 void free_initrd_mem(unsigned long start, unsigned long end)
 342 {
 343         if (start < end)
 344                 printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 345         for (; start < end; start += PAGE_SIZE) {
 346                 ClearPageReserved(virt_to_page(start));
 347                 set_page_count(virt_to_page(start), 1);
 348                 free_page(start);
 349                 totalram_pages++;
 350         }
 351 }
 352 #endif
 353
 354 void si_meminfo(struct sysinfo *val)
 355 {
 356         val->totalram = totalram_pages;
 357         val->sharedram = 0;
 358         val->freeram = nr_free_pages();
 359         val->bufferram = atomic_read(&buffermem_pages);
 360         val->totalhigh = 0;
 361         val->freehigh = 0;
 362         val->mem_unit = PAGE_SIZE;
 363 }
 364
 365 /*
 366  * Overrides for Emacs so that we follow Linus's tabbing style.
 367  * Emacs will notice this stuff at the end of the file and automatically
 368  * adjust the settings for this buffer only.  This must remain at the end
 369  * of the file.
 370  * ---------------------------------------------------------------------------
 371  * Local variables:
 372  * c-indent-level: 4
 373  * c-brace-imaginary-offset: 0
 374  * c-brace-offset: -4
 375  * c-argdecl-indent: 4
 376  * c-label-offset: -4
 377  * c-continued-statement-offset: 4
 378  * c-continued-brace-offset: 0
 379  * indent-tabs-mode: nil
 380  * tab-width: 8
 381  * End:
 382  */