arch/s390/pci/pci_mmio.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Access to PCI I/O memory from user space programs.
   4  *
   5  * Copyright IBM Corp. 2014
   6  * Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/syscalls.h>
  10 #include <linux/init.h>
  11 #include <linux/mm.h>
  12 #include <linux/errno.h>
  13 #include <linux/pci.h>
  14
  15 static long get_pfn(unsigned long user_addr, unsigned long access,
  16                     unsigned long *pfn)
  17 {
  18         struct vm_area_struct *vma;
  19         long ret;
  20
  21         down_read(&current->mm->mmap_sem);
  22         ret = -EINVAL;
  23         vma = find_vma(current->mm, user_addr);
  24         if (!vma)
  25                 goto out;
  26         ret = -EACCES;
  27         if (!(vma->vm_flags & access))
  28                 goto out;
  29         ret = follow_pfn(vma, user_addr, pfn);
  30 out:
  31         up_read(&current->mm->mmap_sem);
  32         return ret;
  33 }
  34
  35 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
  36                 const void __user *, user_buffer, size_t, length)
  37 {
  38         u8 local_buf[64];
  39         void __iomem *io_addr;
  40         void *buf;
  41         unsigned long pfn;
  42         long ret;
  43
  44         if (!zpci_is_enabled())
  45                 return -ENODEV;
  46
  47         if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
  48                 return -EINVAL;
  49         if (length > 64) {
  50                 buf = kmalloc(length, GFP_KERNEL);
  51                 if (!buf)
  52                         return -ENOMEM;
  53         } else
  54                 buf = local_buf;
  55
  56         ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
  57         if (ret)
  58                 goto out;
  59         io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
  60
  61         ret = -EFAULT;
  62         if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
  63                 goto out;
  64
  65         if (copy_from_user(buf, user_buffer, length))
  66                 goto out;
  67
  68         ret = zpci_memcpy_toio(io_addr, buf, length);
  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         if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
 102                 ret = -EFAULT;
 103                 goto out;
 104         }
 105         ret = zpci_memcpy_fromio(buf, io_addr, length);
 106         if (ret)
 107                 goto out;
 108         if (copy_to_user(user_buffer, buf, length))
 109                 ret = -EFAULT;
 110
 111 out:
 112         if (buf != local_buf)
 113                 kfree(buf);
 114         return ret;
 115 }