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> 10#include <linux/security.h> 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; 23 int cfg_ret; 24 25 err = -EPERM; 26 dev = NULL; 27 if (!capable(CAP_SYS_ADMIN)) 28 goto error; 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; 51 if (cfg_ret) 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 96 if (!capable(CAP_SYS_ADMIN) || 97 security_locked_down(LOCKDOWN_PCI_ACCESS)) 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); 110 if (err) 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); 119 if (err) 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); 128 if (err) 129 err = -EIO; 130 break; 131 132 default: 133 err = -EINVAL; 134 break; 135 } 136 pci_dev_put(dev); 137 return err; 138} 139