Viewing file:  syscall.c (2.62 KB) -rw-r--r--
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/*
* pci_syscall.c
*
* For architectures where we want to allow direct access
* to the PCI config stuff - it would probably be preferable
* on PCs too, but there people just do it by hand with the
* magic northbridge registers..
*/
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
asmlinkage long
sys_pciconfig_read(unsigned long bus, unsigned long dfn,
unsigned long off, unsigned long len, void *buf)
{
struct pci_dev *dev;
u8 byte;
u16 word;
u32 dword;
long err, cfg_ret;
err = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto error;
err = -ENODEV;
dev = pci_find_slot(bus, dfn);
if (!dev)
goto error;
lock_kernel();
switch (len) {
case 1:
cfg_ret = pci_read_config_byte(dev, off, &byte);
break;
case 2:
cfg_ret = pci_read_config_word(dev, off, &word);
break;
case 4:
cfg_ret = pci_read_config_dword(dev, off, &dword);
break;
default:
err = -EINVAL;
unlock_kernel();
goto error;
};
unlock_kernel();
err = -EIO;
if (cfg_ret != PCIBIOS_SUCCESSFUL)
goto error;
switch (len) {
case 1:
err = put_user(byte, (unsigned char *)buf);
break;
case 2:
err = put_user(word, (unsigned short *)buf);
break;
case 4:
err = put_user(dword, (unsigned int *)buf);
break;
};
return err;
error:
/* ??? XFree86 doesn't even check the return value. They
just look for 0xffffffff in the output, since that's what
they get instead of a machine check on x86. */
switch (len) {
case 1:
put_user(-1, (unsigned char *)buf);
break;
case 2:
put_user(-1, (unsigned short *)buf);
break;
case 4:
put_user(-1, (unsigned int *)buf);
break;
};
return err;
}
asmlinkage long
sys_pciconfig_write(unsigned long bus, unsigned long dfn,
unsigned long off, unsigned long len, void *buf)
{
struct pci_dev *dev;
u8 byte;
u16 word;
u32 dword;
int err = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!pcibios_present())
return -ENOSYS;
dev = pci_find_slot(bus, dfn);
if (!dev)
return -ENODEV;
lock_kernel();
switch(len) {
case 1:
err = get_user(byte, (u8 *)buf);
if (err)
break;
err = pci_write_config_byte(dev, off, byte);
if (err != PCIBIOS_SUCCESSFUL)
err = -EIO;
break;
case 2:
err = get_user(word, (u16 *)buf);
if (err)
break;
err = pci_write_config_word(dev, off, word);
if (err != PCIBIOS_SUCCESSFUL)
err = -EIO;
break;
case 4:
err = get_user(dword, (u32 *)buf);
if (err)
break;
err = pci_write_config_dword(dev, off, dword);
if (err != PCIBIOS_SUCCESSFUL)
err = -EIO;
break;
default:
err = -EINVAL;
break;
};
unlock_kernel();
return err;
}
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