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/smp_lock.h>
  13 #include <linux/syscalls.h>
  14 #include <asm/uaccess.h>
  15 #include "pci.h"
  16
  17 asmlinkage long
  18 sys_pciconfig_read(unsigned long bus, unsigned long dfn,
  19                    unsigned long off, unsigned long len,
  20                    void __user *buf)
  21 {
  22         struct pci_dev *dev;
  23         u8 byte;
  24         u16 word;
  25         u32 dword;
  26         long err;
  27         long cfg_ret;
  28
  29         if (!capable(CAP_SYS_ADMIN))
  30                 return -EPERM;
  31
  32         err = -ENODEV;
  33         dev = pci_get_bus_and_slot(bus, dfn);
  34         if (!dev)
  35                 goto error;
  36
  37         lock_kernel();
  38         switch (len) {
  39         case 1:
  40                 cfg_ret = pci_user_read_config_byte(dev, off, &byte);
  41                 break;
  42         case 2:
  43                 cfg_ret = pci_user_read_config_word(dev, off, &word);
  44                 break;
  45         case 4:
  46                 cfg_ret = pci_user_read_config_dword(dev, off, &dword);
  47                 break;
  48         default:
  49                 err = -EINVAL;
  50                 unlock_kernel();
  51                 goto error;
  52         };
  53         unlock_kernel();
  54
  55         err = -EIO;
  56         if (cfg_ret != PCIBIOS_SUCCESSFUL)
  57                 goto error;
  58
  59         switch (len) {
  60         case 1:
  61                 err = put_user(byte, (unsigned char __user *)buf);
  62                 break;
  63         case 2:
  64                 err = put_user(word, (unsigned short __user *)buf);
  65                 break;
  66         case 4:
  67                 err = put_user(dword, (unsigned int __user *)buf);
  68                 break;
  69         }
  70         pci_dev_put(dev);
  71         return err;
  72
  73 error:
  74         /* ??? XFree86 doesn't even check the return value.  They
  75            just look for 0xffffffff in the output, since that's what
  76            they get instead of a machine check on x86.  */
  77         switch (len) {
  78         case 1:
  79                 put_user(-1, (unsigned char __user *)buf);
  80                 break;
  81         case 2:
  82                 put_user(-1, (unsigned short __user *)buf);
  83                 break;
  84         case 4:
  85                 put_user(-1, (unsigned int __user *)buf);
  86                 break;
  87         }
  88         pci_dev_put(dev);
  89         return err;
  90 }
  91
  92 asmlinkage long
  93 sys_pciconfig_write(unsigned long bus, unsigned long dfn,
  94                     unsigned long off, unsigned long len,
  95                     void __user *buf)
  96 {
  97         struct pci_dev *dev;
  98         u8 byte;
  99         u16 word;
 100         u32 dword;
 101         int err = 0;
 102
 103         if (!capable(CAP_SYS_ADMIN))
 104                 return -EPERM;
 105
 106         dev = pci_get_bus_and_slot(bus, dfn);
 107         if (!dev)
 108                 return -ENODEV;
 109
 110         lock_kernel();
 111         switch(len) {
 112         case 1:
 113                 err = get_user(byte, (u8 __user *)buf);
 114                 if (err)
 115                         break;
 116                 err = pci_user_write_config_byte(dev, off, byte);
 117                 if (err != PCIBIOS_SUCCESSFUL)
 118                         err = -EIO;
 119                 break;
 120
 121         case 2:
 122                 err = get_user(word, (u16 __user *)buf);
 123                 if (err)
 124                         break;
 125                 err = pci_user_write_config_word(dev, off, word);
 126                 if (err != PCIBIOS_SUCCESSFUL)
 127                         err = -EIO;
 128                 break;
 129
 130         case 4:
 131                 err = get_user(dword, (u32 __user *)buf);
 132                 if (err)
 133                         break;
 134                 err = pci_user_write_config_dword(dev, off, dword);
 135                 if (err != PCIBIOS_SUCCESSFUL)
 136                         err = -EIO;
 137                 break;
 138
 139         default:
 140                 err = -EINVAL;
 141                 break;
 142         }
 143         unlock_kernel();
 144         pci_dev_put(dev);
 145         return err;
 146 }