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review.trustedfirmware.org / hafnium / third_party / linux / 0e64123141f3854e695eb4924d82b52856691466 / . / drivers / pci / syscall.c
blob: c9f03418e71e09ad1a38c3eae2ffd82d91bccf75 [file] [log] [blame]
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]1// SPDX-License-Identifier: GPL-2.0
2/*
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.
6 */
7
8#include <linux/errno.h>
9#include <linux/pci.h>
David Brazdil0f672f62019-12-10 10:32:29 +0000[diff] [blame]10#include <linux/security.h>
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]11#include <linux/syscalls.h>
12#include <linux/uaccess.h>
13#include "pci.h"
14
15SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,
16 unsigned long, off, unsigned long, len, void __user *, buf)
17{
18 struct pci_dev *dev;
19 u8 byte;
20 u16 word;
21 u32 dword;
22 long err;
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]23 int cfg_ret;
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]24
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]25 err = -EPERM;
26 dev = NULL;
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]27 if (!capable(CAP_SYS_ADMIN))
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]28 goto error;
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]29
30 err = -ENODEV;
31 dev = pci_get_domain_bus_and_slot(0, bus, dfn);
32 if (!dev)
33 goto error;
34
35 switch (len) {
36 case 1:
37 cfg_ret = pci_user_read_config_byte(dev, off, &byte);
38 break;
39 case 2:
40 cfg_ret = pci_user_read_config_word(dev, off, &word);
41 break;
42 case 4:
43 cfg_ret = pci_user_read_config_dword(dev, off, &dword);
44 break;
45 default:
46 err = -EINVAL;
47 goto error;
48 }
49
50 err = -EIO;
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]51 if (cfg_ret)
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]52 goto error;
53
54 switch (len) {
55 case 1:
56 err = put_user(byte, (unsigned char __user *)buf);
57 break;
58 case 2:
59 err = put_user(word, (unsigned short __user *)buf);
60 break;
61 case 4:
62 err = put_user(dword, (unsigned int __user *)buf);
63 break;
64 }
65 pci_dev_put(dev);
66 return err;
67
68error:
69 /* ??? XFree86 doesn't even check the return value. They
70 just look for 0xffffffff in the output, since that's what
71 they get instead of a machine check on x86. */
72 switch (len) {
73 case 1:
74 put_user(-1, (unsigned char __user *)buf);
75 break;
76 case 2:
77 put_user(-1, (unsigned short __user *)buf);
78 break;
79 case 4:
80 put_user(-1, (unsigned int __user *)buf);
81 break;
82 }
83 pci_dev_put(dev);
84 return err;
85}
86
87SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,
88 unsigned long, off, unsigned long, len, void __user *, buf)
89{
90 struct pci_dev *dev;
91 u8 byte;
92 u16 word;
93 u32 dword;
94 int err = 0;
95
David Brazdil0f672f62019-12-10 10:32:29 +0000[diff] [blame]96 if (!capable(CAP_SYS_ADMIN) ||
97 security_locked_down(LOCKDOWN_PCI_ACCESS))
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]98 return -EPERM;
99
100 dev = pci_get_domain_bus_and_slot(0, bus, dfn);
101 if (!dev)
102 return -ENODEV;
103
104 switch (len) {
105 case 1:
106 err = get_user(byte, (u8 __user *)buf);
107 if (err)
108 break;
109 err = pci_user_write_config_byte(dev, off, byte);
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]110 if (err)
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]111 err = -EIO;
112 break;
113
114 case 2:
115 err = get_user(word, (u16 __user *)buf);
116 if (err)
117 break;
118 err = pci_user_write_config_word(dev, off, word);
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]119 if (err)
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]120 err = -EIO;
121 break;
122
123 case 4:
124 err = get_user(dword, (u32 __user *)buf);
125 if (err)
126 break;
127 err = pci_user_write_config_dword(dev, off, dword);
Olivier Deprez0e641232021-09-23 10:07:05 +0200[diff] [blame^]128 if (err)
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000[diff] [blame]129 err = -EIO;
130 break;
131
132 default:
133 err = -EINVAL;
134 break;
135 }
136 pci_dev_put(dev);
137 return err;
138}