arch/s390/kernel/compat_exec.c

   1 /*
   2  * Support for 32-bit Linux for S390 ELF binaries.
   3  *
   4  * Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   5  * Author(s): Gerhard Tonn (ton@de.ibm.com)
   6  *
   7  * Separated from binfmt_elf32.c to reduce exports for module enablement.
   8  *
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/slab.h>
  13 #include <linux/file.h>
  14 #include <linux/mman.h>
  15 #include <linux/a.out.h>
  16 #include <linux/stat.h>
  17 #include <linux/fcntl.h>
  18 #include <linux/smp_lock.h>
  19 #include <linux/init.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/mm.h>
  22 #include <linux/highmem.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/module.h>
  26 #include <linux/security.h>
  27
  28 #include <asm/uaccess.h>
  29 #include <asm/pgalloc.h>
  30 #include <asm/mmu_context.h>
  31
  32 #ifdef CONFIG_KMOD
  33 #include <linux/kmod.h>
  34 #endif
  35
  36
  37 #undef STACK_TOP
  38 #define STACK_TOP TASK31_SIZE
  39
  40 int setup_arg_pages32(struct linux_binprm *bprm, int executable_stack)
  41 {
  42         unsigned long stack_base, grow;
  43         struct vm_area_struct *mpnt;
  44         struct mm_struct *mm = current->mm;
  45         int i;
  46
  47         stack_base = STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
  48         mm->arg_start = bprm->p + stack_base;
  49
  50         bprm->p += stack_base;
  51         if (bprm->loader)
  52                 bprm->loader += stack_base;
  53         bprm->exec += stack_base;
  54
  55         mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
  56         if (!mpnt)
  57                 return -ENOMEM;
  58
  59         grow = (STACK_TOP - (PAGE_MASK & (unsigned long) bprm->p))
  60                 >> PAGE_SHIFT;
  61         if (security_vm_enough_memory(grow) ||
  62                 !vx_vmpages_avail(mm, grow)) {
  63                 kmem_cache_free(vm_area_cachep, mpnt);
  64                 return -ENOMEM;
  65         }
  66
  67         down_write(&mm->mmap_sem);
  68         {
  69                 mpnt->vm_mm = mm;
  70                 mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
  71                 mpnt->vm_end = STACK_TOP;
  72                 /* executable stack setting would be applied here */
  73                 mpnt->vm_page_prot = PAGE_COPY;
  74                 mpnt->vm_flags = VM_STACK_FLAGS;
  75                 mpnt->vm_ops = NULL;
  76                 mpnt->vm_pgoff = 0;
  77                 mpnt->vm_file = NULL;
  78                 INIT_LIST_HEAD(&mpnt->shared);
  79                 mpnt->vm_private_data = (void *) 0;
  80                 insert_vm_struct(mm, mpnt);
  81                 // mm->total_vm = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
  82                 vx_vmpages_sub(mm, mm->total_vm -
  83                         ((mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT));
  84         }
  85
  86         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
  87                 struct page *page = bprm->page[i];
  88                 if (page) {
  89                         bprm->page[i] = NULL;
  90                         put_dirty_page(current,page,stack_base,PAGE_COPY);
  91                 }
  92                 stack_base += PAGE_SIZE;
  93         }
  94         up_write(&mm->mmap_sem);
  95
  96         return 0;
  97 }
  98
  99 EXPORT_SYMBOL(setup_arg_pages32);