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/sched.h>
  11 #include <linux/errno.h>
  12 #include <linux/pci.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/syscalls.h>
  15 #include <asm/uaccess.h>
  16
  17
  18 asmlinkage long
  19 sys_pciconfig_read(unsigned long bus, unsigned long dfn,
  20                    unsigned long off, unsigned long len,
  21                    void __user *buf)
  22 {
  23         struct pci_dev *dev;
  24         u8 byte;
  25         u16 word;
  26         u32 dword;
  27         long err, cfg_ret;
  28
  29         err = -EPERM;
  30         if (!capable(CAP_SYS_ADMIN))
  31                 goto error;
  32
  33         err = -ENODEV;
  34         dev = pci_find_slot(bus, dfn);
  35         if (!dev)
  36                 goto error;
  37
  38         lock_kernel();
  39         switch (len) {
  40         case 1:
  41                 cfg_ret = pci_read_config_byte(dev, off, &byte);
  42                 break;
  43         case 2:
  44                 cfg_ret = pci_read_config_word(dev, off, &word);
  45                 break;
  46         case 4:
  47                 cfg_ret = pci_read_config_dword(dev, off, &dword);
  48                 break;
  49         default:
  50                 err = -EINVAL;
  51                 unlock_kernel();
  52                 goto error;
  53         };
  54         unlock_kernel();
  55
  56         err = -EIO;
  57         if (cfg_ret != PCIBIOS_SUCCESSFUL)
  58                 goto error;
  59
  60         switch (len) {
  61         case 1:
  62                 err = put_user(byte, (unsigned char __user *)buf);
  63                 break;
  64         case 2:
  65                 err = put_user(word, (unsigned short __user *)buf);
  66                 break;
  67         case 4:
  68                 err = put_user(dword, (unsigned int __user *)buf);
  69                 break;
  70         };
  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         return err;
  89 }
  90
  91 asmlinkage long
  92 sys_pciconfig_write(unsigned long bus, unsigned long dfn,
  93                     unsigned long off, unsigned long len,
  94                     void __user *buf)
  95 {
  96         struct pci_dev *dev;
  97         u8 byte;
  98         u16 word;
  99         u32 dword;
 100         int err = 0;
 101
 102         if (!capable(CAP_SYS_ADMIN))
 103                 return -EPERM;
 104
 105         dev = pci_find_slot(bus, dfn);
 106         if (!dev)
 107                 return -ENODEV;
 108
 109         lock_kernel();
 110         switch(len) {
 111         case 1:
 112                 err = get_user(byte, (u8 __user *)buf);
 113                 if (err)
 114                         break;
 115                 err = pci_write_config_byte(dev, off, byte);
 116                 if (err != PCIBIOS_SUCCESSFUL)
 117                         err = -EIO;
 118                 break;
 119
 120         case 2:
 121                 err = get_user(word, (u16 __user *)buf);
 122                 if (err)
 123                         break;
 124                 err = pci_write_config_word(dev, off, word);
 125                 if (err != PCIBIOS_SUCCESSFUL)
 126                         err = -EIO;
 127                 break;
 128
 129         case 4:
 130                 err = get_user(dword, (u32 __user *)buf);
 131                 if (err)
 132                         break;
 133                 err = pci_write_config_dword(dev, off, dword);
 134                 if (err != PCIBIOS_SUCCESSFUL)
 135                         err = -EIO;
 136                 break;
 137
 138         default:
 139                 err = -EINVAL;
 140                 break;
 141         };
 142         unlock_kernel();
 143
 144         return err;
 145 }