arch/s390/mm/pgtable.c

   1 /*
   2  *  arch/s390/mm/pgtable.c
   3  *
   4  *    Copyright IBM Corp. 2007
   5  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   6  */
   7
   8 #include <linux/sched.h>
   9 #include <linux/kernel.h>
  10 #include <linux/errno.h>
  11 #include <linux/mm.h>
  12 #include <linux/swap.h>
  13 #include <linux/smp.h>
  14 #include <linux/highmem.h>
  15 #include <linux/slab.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/module.h>
  19 #include <linux/quicklist.h>
  20
  21 #include <asm/system.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/pgalloc.h>
  24 #include <asm/tlb.h>
  25 #include <asm/tlbflush.h>
  26
  27 #ifndef CONFIG_64BIT
  28 #define ALLOC_ORDER     1
  29 #else
  30 #define ALLOC_ORDER     2
  31 #endif
  32
  33 unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec)
  34 {
  35         struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
  36
  37         if (!page)
  38                 return NULL;
  39         page->index = 0;
  40         if (noexec) {
  41                 struct page *shadow = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
  42                 if (!shadow) {
  43                         __free_pages(page, ALLOC_ORDER);
  44                         return NULL;
  45                 }
  46                 page->index = page_to_phys(shadow);
  47         }
  48         return (unsigned long *) page_to_phys(page);
  49 }
  50
  51 void crst_table_free(unsigned long *table)
  52 {
  53         unsigned long *shadow = get_shadow_table(table);
  54
  55         if (shadow)
  56                 free_pages((unsigned long) shadow, ALLOC_ORDER);
  57         free_pages((unsigned long) table, ALLOC_ORDER);
  58 }
  59
  60 /*
  61  * page table entry allocation/free routines.
  62  */
  63 unsigned long *page_table_alloc(int noexec)
  64 {
  65         struct page *page = alloc_page(GFP_KERNEL);
  66         unsigned long *table;
  67
  68         if (!page)
  69                 return NULL;
  70         page->index = 0;
  71         if (noexec) {
  72                 struct page *shadow = alloc_page(GFP_KERNEL);
  73                 if (!shadow) {
  74                         __free_page(page);
  75                         return NULL;
  76                 }
  77                 table = (unsigned long *) page_to_phys(shadow);
  78                 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
  79                 page->index = (addr_t) table;
  80         }
  81         table = (unsigned long *) page_to_phys(page);
  82         clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
  83         return table;
  84 }
  85
  86 void page_table_free(unsigned long *table)
  87 {
  88         unsigned long *shadow = get_shadow_pte(table);
  89
  90         if (shadow)
  91                 free_page((unsigned long) shadow);
  92         free_page((unsigned long) table);
  93
  94 }