LXR linux/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 <asm/uaccess.h>
  14#include "pci.h"
  15
  16SYSCALL_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
  67error:
  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
  86SYSCALL_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}
 137