root/arch/csky/kernel/vdso.c

DEFINITIONS

1. init_vdso
2. arch_setup_additional_pages
3. arch_vma_name

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3 
   4 #include <linux/kernel.h>
   5 #include <linux/err.h>
   6 #include <linux/sched.h>
   7 #include <linux/mm.h>
   8 #include <linux/init.h>
   9 #include <linux/binfmts.h>
  10 #include <linux/elf.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/unistd.h>
  13 #include <linux/uaccess.h>
  14 
  15 #include <asm/vdso.h>
  16 #include <asm/cacheflush.h>
  17 
  18 static struct page *vdso_page;
  19 
  20 static int __init init_vdso(void)
  21 {
  22         struct csky_vdso *vdso;
  23         int err = 0;
  24 
  25         vdso_page = alloc_page(GFP_KERNEL);
  26         if (!vdso_page)
  27                 panic("Cannot allocate vdso");
  28 
  29         vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
  30         if (!vdso)
  31                 panic("Cannot map vdso");
  32 
  33         clear_page(vdso);
  34 
  35         err = setup_vdso_page(vdso->rt_signal_retcode);
  36         if (err)
  37                 panic("Cannot set signal return code, err: %x.", err);
  38 
  39         dcache_wb_range((unsigned long)vdso, (unsigned long)vdso + 16);
  40 
  41         vunmap(vdso);
  42 
  43         return 0;
  44 }
  45 subsys_initcall(init_vdso);
  46 
  47 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
  48 {
  49         int ret;
  50         unsigned long addr;
  51         struct mm_struct *mm = current->mm;
  52 
  53         down_write(&mm->mmap_sem);
  54 
  55         addr = get_unmapped_area(NULL, STACK_TOP, PAGE_SIZE, 0, 0);
  56         if (IS_ERR_VALUE(addr)) {
  57                 ret = addr;
  58                 goto up_fail;
  59         }
  60 
  61         ret = install_special_mapping(
  62                         mm,
  63                         addr,
  64                         PAGE_SIZE,
  65                         VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
  66                         &vdso_page);
  67         if (ret)
  68                 goto up_fail;
  69 
  70         mm->context.vdso = (void *)addr;
  71 
  72 up_fail:
  73         up_write(&mm->mmap_sem);
  74         return ret;
  75 }
  76 
  77 const char *arch_vma_name(struct vm_area_struct *vma)
  78 {
  79         if (vma->vm_mm == NULL)
  80                 return NULL;
  81 
  82         if (vma->vm_start == (long)vma->vm_mm->context.vdso)
  83                 return "[vdso]";
  84         else
  85                 return NULL;
  86 }