drivers/pci/syscall.c

   1 /*
   2  *      pci_syscall.c
   3  *
   4  * For architectures where we want to allow direct access
   5  * to the PCI config stuff - it would probably be preferable
   6  * on PCs too, but there people just do it by hand with the
   7  * magic northbridge registers..
   8  */
   9
  10 #include <linux/errno.h>
  11 #include <linux/pci.h>
  12 #include <linux/syscalls.h>
  13 #include <linux/uaccess.h>
  14 #include "pci.h"
  15
  16 SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,
  17                 unsigned long, off, unsigned long, len, void __user *, buf)
  18 {
  19         struct pci_dev *dev;
  20         u8 byte;
  21         u16 word;
  22         u32 dword;
  23         long err;
  24         long cfg_ret;
  25
  26         if (!capable(CAP_SYS_ADMIN))
  27                 return -EPERM;
  28
  29         err = -ENODEV;
  30         dev = pci_get_bus_and_slot(bus, dfn);
  31         if (!dev)
  32                 goto error;
  33
  34         switch (len) {
  35         case 1:
  36                 cfg_ret = pci_user_read_config_byte(dev, off, &byte);
  37                 break;
  38         case 2:
  39                 cfg_ret = pci_user_read_config_word(dev, off, &word);
  40                 break;
  41         case 4:
  42                 cfg_ret = pci_user_read_config_dword(dev, off, &dword);
  43                 break;
  44         default:
  45                 err = -EINVAL;
  46                 goto error;
  47         }
  48
  49         err = -EIO;
  50         if (cfg_ret != PCIBIOS_SUCCESSFUL)
  51                 goto error;
  52
  53         switch (len) {
  54         case 1:
  55                 err = put_user(byte, (unsigned char __user *)buf);
  56                 break;
  57         case 2:
  58                 err = put_user(word, (unsigned short __user *)buf);
  59                 break;
  60         case 4:
  61                 err = put_user(dword, (unsigned int __user *)buf);
  62                 break;
  63         }
  64         pci_dev_put(dev);
  65         return err;
  66
  67 error:
  68         /* ??? XFree86 doesn't even check the return value.  They
  69            just look for 0xffffffff in the output, since that's what
  70            they get instead of a machine check on x86.  */
  71         switch (len) {
  72         case 1:
  73                 put_user(-1, (unsigned char __user *)buf);
  74                 break;
  75         case 2:
  76                 put_user(-1, (unsigned short __user *)buf);
  77                 break;
  78         case 4:
  79                 put_user(-1, (unsigned int __user *)buf);
  80                 break;
  81         }
  82         pci_dev_put(dev);
  83         return err;
  84 }
  85
  86 SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,
  87                 unsigned long, off, unsigned long, len, void __user *, buf)
  88 {
  89         struct pci_dev *dev;
  90         u8 byte;
  91         u16 word;
  92         u32 dword;
  93         int err = 0;
  94
  95         if (!capable(CAP_SYS_ADMIN))
  96                 return -EPERM;
  97
  98         dev = pci_get_bus_and_slot(bus, dfn);
  99         if (!dev)
 100                 return -ENODEV;
 101
 102         switch (len) {
 103         case 1:
 104                 err = get_user(byte, (u8 __user *)buf);
 105                 if (err)
 106                         break;
 107                 err = pci_user_write_config_byte(dev, off, byte);
 108                 if (err != PCIBIOS_SUCCESSFUL)
 109                         err = -EIO;
 110                 break;
 111
 112         case 2:
 113                 err = get_user(word, (u16 __user *)buf);
 114                 if (err)
 115                         break;
 116                 err = pci_user_write_config_word(dev, off, word);
 117                 if (err != PCIBIOS_SUCCESSFUL)
 118                         err = -EIO;
 119                 break;
 120
 121         case 4:
 122                 err = get_user(dword, (u32 __user *)buf);
 123                 if (err)
 124                         break;
 125                 err = pci_user_write_config_dword(dev, off, dword);
 126                 if (err != PCIBIOS_SUCCESSFUL)
 127                         err = -EIO;
 128                 break;
 129
 130         default:
 131                 err = -EINVAL;
 132                 break;
 133         }
 134         pci_dev_put(dev);
 135         return err;
 136 }