[linux-block.git] / drivers / pci / syscall.c

// 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;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4	2	/*
df62ab5e BH	3	* For architectures where we want to allow direct access to the PCI config
	4	* stuff - it would probably be preferable on PCs too, but there people
	5	* just do it by hand with the magic northbridge registers.
1da177e4 LT	6	*/
1da177e4 LT	7
1da177e4 LT	8	#include <linux/errno.h>
1da177e4 LT	9	#include <linux/pci.h>
eb627e17	10	#include <linux/security.h>
1da177e4	11	#include <linux/syscalls.h>
7c0f6ba6	12	#include <linux/uaccess.h>
e04b0ea2	13	#include "pci.h"
1da177e4	14
c4ea37c2 HC	15	SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,
c4ea37c2 HC	16	unsigned long, off, unsigned long, len, void __user *, buf)
1da177e4 LT	17	{
	18	struct pci_dev *dev;
	19	u8 byte;
	20	u16 word;
	21	u32 dword;
d6b17159	22	int err, cfg_ret;
1da177e4	23
a8bd29bd KW	24	err = -EPERM;
a8bd29bd KW	25	dev = NULL;
1da177e4	26	if (!capable(CAP_SYS_ADMIN))
a8bd29bd	27	goto error;
1da177e4 LT	28
1da177e4 LT	29	err = -ENODEV;
39c94652	30	dev = pci_get_domain_bus_and_slot(0, bus, dfn);
1da177e4 LT	31	if (!dev)
	32	goto error;
	33
1da177e4 LT	34	switch (len) {
1da177e4 LT	35	case 1:
e04b0ea2	36	cfg_ret = pci_user_read_config_byte(dev, off, &byte);
1da177e4 LT	37	break;
1da177e4 LT	38	case 2:
e04b0ea2	39	cfg_ret = pci_user_read_config_word(dev, off, &word);
1da177e4 LT	40	break;
1da177e4 LT	41	case 4:
e04b0ea2	42	cfg_ret = pci_user_read_config_dword(dev, off, &dword);
1da177e4 LT	43	break;
	44	default:
	45	err = -EINVAL;
1da177e4	46	goto error;
f7625980	47	}
1da177e4 LT	48
1da177e4 LT	49	err = -EIO;
ef9e4005	50	if (cfg_ret)
1da177e4 LT	51	goto error;
	52
	53	switch (len) {
	54	case 1:
32e2a3f9	55	err = put_user(byte, (u8 __user *)buf);
1da177e4 LT	56	break;
1da177e4 LT	57	case 2:
32e2a3f9	58	err = put_user(word, (u16 __user *)buf);
1da177e4 LT	59	break;
1da177e4 LT	60	case 4:
32e2a3f9	61	err = put_user(dword, (u32 __user *)buf);
1da177e4	62	break;
e4585da2 AC	63	}
e4585da2 AC	64	pci_dev_put(dev);
1da177e4 LT	65	return err;
	66
	67	error:
	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:
32e2a3f9	73	put_user(-1, (u8 __user *)buf);
1da177e4 LT	74	break;
1da177e4 LT	75	case 2:
32e2a3f9	76	put_user(-1, (u16 __user *)buf);
1da177e4 LT	77	break;
1da177e4 LT	78	case 4:
32e2a3f9	79	put_user(-1, (u32 __user *)buf);
1da177e4	80	break;
e4585da2 AC	81	}
e4585da2 AC	82	pci_dev_put(dev);
1da177e4 LT	83	return err;
	84	}
	85
c4ea37c2 HC	86	SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,
c4ea37c2 HC	87	unsigned long, off, unsigned long, len, void __user *, buf)
1da177e4 LT	88	{
	89	struct pci_dev *dev;
	90	u8 byte;
	91	u16 word;
	92	u32 dword;
	93	int err = 0;
	94
eb627e17 MG	95	if (!capable(CAP_SYS_ADMIN) \|\|
eb627e17 MG	96	security_locked_down(LOCKDOWN_PCI_ACCESS))
1da177e4 LT	97	return -EPERM;
1da177e4 LT	98
39c94652	99	dev = pci_get_domain_bus_and_slot(0, bus, dfn);
1da177e4 LT	100	if (!dev)
	101	return -ENODEV;
	102
3c78bc61	103	switch (len) {
1da177e4 LT	104	case 1:
	105	err = get_user(byte, (u8 __user *)buf);
	106	if (err)
	107	break;
e04b0ea2	108	err = pci_user_write_config_byte(dev, off, byte);
ef9e4005	109	if (err)
1da177e4 LT	110	err = -EIO;
	111	break;
	112
	113	case 2:
	114	err = get_user(word, (u16 __user *)buf);
	115	if (err)
	116	break;
e04b0ea2	117	err = pci_user_write_config_word(dev, off, word);
ef9e4005	118	if (err)
1da177e4 LT	119	err = -EIO;
	120	break;
	121
	122	case 4:
	123	err = get_user(dword, (u32 __user *)buf);
	124	if (err)
	125	break;
e04b0ea2	126	err = pci_user_write_config_dword(dev, off, dword);
ef9e4005	127	if (err)
1da177e4 LT	128	err = -EIO;
	129	break;
	130
	131	default:
	132	err = -EINVAL;
	133	break;
e4585da2	134	}
e4585da2	135	pci_dev_put(dev);
1da177e4 LT	136	return err;
1da177e4 LT	137	}