// SPDX-License-Identifier: GPL-2.0/* * 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/errno.h>#include <linux/pci.h>#include <linux/security.h>#include <linux/syscalls.h>#include <linux/uaccess.h>#include "pci.h" SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,		unsigned long, off, unsigned long, len, void __user *, buf){	struct pci_dev *dev;	u8 byte;	u16 word;	u32 dword;	int err, cfg_ret; 	err = -EPERM;	dev = NULL;	if (!capable(CAP_SYS_ADMIN))		goto error; 	err = -ENODEV;	dev = pci_get_domain_bus_and_slot(0, bus, dfn);	if (!dev)		goto error; 	switch (len) {	case 1:		cfg_ret = pci_user_read_config_byte(dev, off, &byte);		break;	case 2:		cfg_ret = pci_user_read_config_word(dev, off, &word);		break;	case 4:		cfg_ret = pci_user_read_config_dword(dev, off, &dword);		break;	default:		err = -EINVAL;		goto error;	} 	err = -EIO;	if (cfg_ret)		goto error; 	switch (len) {	case 1:		err = put_user(byte, (u8 __user *)buf);		break;	case 2:		err = put_user(word, (u16 __user *)buf);		break;	case 4:		err = put_user(dword, (u32 __user *)buf);		break;	}	pci_dev_put(dev);	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, (u8 __user *)buf);		break;	case 2:		put_user(-1, (u16 __user *)buf);		break;	case 4:		put_user(-1, (u32 __user *)buf);		break;	}	pci_dev_put(dev);	return err;} SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,		unsigned long, off, unsigned long, len, void __user *, buf){	struct pci_dev *dev;	u8 byte;	u16 word;	u32 dword;	int err = 0; 	if (!capable(CAP_SYS_ADMIN) ||	    security_locked_down(LOCKDOWN_PCI_ACCESS))		return -EPERM; 	dev = pci_get_domain_bus_and_slot(0, bus, dfn);	if (!dev)		return -ENODEV; 	switch (len) {	case 1:		err = get_user(byte, (u8 __user *)buf);		if (err)			break;		err = pci_user_write_config_byte(dev, off, byte);		if (err)			err = -EIO;		break; 	case 2:		err = get_user(word, (u16 __user *)buf);		if (err)			break;		err = pci_user_write_config_word(dev, off, word);		if (err)			err = -EIO;		break; 	case 4:		err = get_user(dword, (u32 __user *)buf);		if (err)			break;		err = pci_user_write_config_dword(dev, off, dword);		if (err)			err = -EIO;		break; 	default:		err = -EINVAL;		break;	}	pci_dev_put(dev);	return err;}