arch/s390/pci/pci_mmio.c

   1 /*
   2  * Access to PCI I/O memory from user space programs.
   3  *
   4  * Copyright IBM Corp. 2014
   5  * Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/syscalls.h>
   9 #include <linux/init.h>
  10 #include <linux/mm.h>
  11 #include <linux/errno.h>
  12 #include <linux/pci.h>
  13
  14 static long get_pfn(unsigned long user_addr, unsigned long access,
  15                     unsigned long *pfn)
  16 {
  17         struct vm_area_struct *vma;
  18         long ret;
  19
  20         down_read(&current->mm->mmap_sem);
  21         ret = -EINVAL;
  22         vma = find_vma(current->mm, user_addr);
  23         if (!vma)
  24                 goto out;
  25         ret = -EACCES;
  26         if (!(vma->vm_flags & access))
  27                 goto out;
  28         ret = follow_pfn(vma, user_addr, pfn);
  29 out:
  30         up_read(&current->mm->mmap_sem);
  31         return ret;
  32 }
  33
  34 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
  35                 const void __user *, user_buffer, size_t, length)
  36 {
  37         u8 local_buf[64];
  38         void __iomem *io_addr;
  39         void *buf;
  40         unsigned long pfn;
  41         long ret;
  42
  43         if (!zpci_is_enabled())
  44                 return -ENODEV;
  45
  46         if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
  47                 return -EINVAL;
  48         if (length > 64) {
  49                 buf = kmalloc(length, GFP_KERNEL);
  50                 if (!buf)
  51                         return -ENOMEM;
  52         } else
  53                 buf = local_buf;
  54
  55         ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
  56         if (ret)
  57                 goto out;
  58         io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
  59
  60         ret = -EFAULT;
  61         if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
  62                 goto out;
  63
  64         if (copy_from_user(buf, user_buffer, length))
  65                 goto out;
  66
  67         memcpy_toio(io_addr, buf, length);
  68         ret = 0;
  69 out:
  70         if (buf != local_buf)
  71                 kfree(buf);
  72         return ret;
  73 }
  74
  75 SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
  76                 void __user *, user_buffer, size_t, length)
  77 {
  78         u8 local_buf[64];
  79         void __iomem *io_addr;
  80         void *buf;
  81         unsigned long pfn;
  82         long ret;
  83
  84         if (!zpci_is_enabled())
  85                 return -ENODEV;
  86
  87         if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
  88                 return -EINVAL;
  89         if (length > 64) {
  90                 buf = kmalloc(length, GFP_KERNEL);
  91                 if (!buf)
  92                         return -ENOMEM;
  93         } else
  94                 buf = local_buf;
  95
  96         ret = get_pfn(mmio_addr, VM_READ, &pfn);
  97         if (ret)
  98                 goto out;
  99         io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
 100
 101         ret = -EFAULT;
 102         if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
 103                 goto out;
 104
 105         memcpy_fromio(buf, io_addr, length);
 106
 107         if (copy_to_user(user_buffer, buf, length))
 108                 goto out;
 109
 110         ret = 0;
 111 out:
 112         if (buf != local_buf)
 113                 kfree(buf);
 114         return ret;
 115 }