drivers/xen/xenfs/xenstored.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/slab.h>
   3 #include <linux/types.h>
   4 #include <linux/mm.h>
   5 #include <linux/fs.h>
   6
   7 #include <xen/page.h>
   8 #include <xen/xenbus.h>
   9
  10 #include "xenfs.h"
  11
  12 static ssize_t xsd_read(struct file *file, char __user *buf,
  13                             size_t size, loff_t *off)
  14 {
  15         const char *str = (const char *)file->private_data;
  16         return simple_read_from_buffer(buf, size, off, str, strlen(str));
  17 }
  18
  19 static int xsd_release(struct inode *inode, struct file *file)
  20 {
  21         kfree(file->private_data);
  22         return 0;
  23 }
  24
  25 static int xsd_kva_open(struct inode *inode, struct file *file)
  26 {
  27         file->private_data = (void *)kasprintf(GFP_KERNEL, "0x%p",
  28                                                xen_store_interface);
  29         if (!file->private_data)
  30                 return -ENOMEM;
  31         return 0;
  32 }
  33
  34 static int xsd_kva_mmap(struct file *file, struct vm_area_struct *vma)
  35 {
  36         size_t size = vma->vm_end - vma->vm_start;
  37
  38         if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
  39                 return -EINVAL;
  40
  41         if (remap_pfn_range(vma, vma->vm_start,
  42                             virt_to_pfn(xen_store_interface),
  43                             size, vma->vm_page_prot))
  44                 return -EAGAIN;
  45
  46         return 0;
  47 }
  48
  49 const struct file_operations xsd_kva_file_ops = {
  50         .open = xsd_kva_open,
  51         .mmap = xsd_kva_mmap,
  52         .read = xsd_read,
  53         .release = xsd_release,
  54 };
  55
  56 static int xsd_port_open(struct inode *inode, struct file *file)
  57 {
  58         file->private_data = (void *)kasprintf(GFP_KERNEL, "%d",
  59                                                xen_store_evtchn);
  60         if (!file->private_data)
  61                 return -ENOMEM;
  62         return 0;
  63 }
  64
  65 const struct file_operations xsd_port_file_ops = {
  66         .open = xsd_port_open,
  67         .read = xsd_read,
  68         .release = xsd_release,
  69 };