syscall.c 2.7 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138
  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. #include <linux/errno.h>
  8. #include <linux/pci.h>
  9. #include <linux/security.h>
  10. #include <linux/syscalls.h>
  11. #include <linux/uaccess.h>
  12. #include "pci.h"
  13. SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,
  14. unsigned long, off, unsigned long, len, void __user *, buf)
  15. {
  16. struct pci_dev *dev;
  17. u8 byte;
  18. u16 word;
  19. u32 dword;
  20. long err;
  21. int cfg_ret;
  22. err = -EPERM;
  23. dev = NULL;
  24. if (!capable(CAP_SYS_ADMIN))
  25. goto error;
  26. err = -ENODEV;
  27. dev = pci_get_domain_bus_and_slot(0, bus, dfn);
  28. if (!dev)
  29. goto error;
  30. switch (len) {
  31. case 1:
  32. cfg_ret = pci_user_read_config_byte(dev, off, &byte);
  33. break;
  34. case 2:
  35. cfg_ret = pci_user_read_config_word(dev, off, &word);
  36. break;
  37. case 4:
  38. cfg_ret = pci_user_read_config_dword(dev, off, &dword);
  39. break;
  40. default:
  41. err = -EINVAL;
  42. goto error;
  43. }
  44. err = -EIO;
  45. if (cfg_ret)
  46. goto error;
  47. switch (len) {
  48. case 1:
  49. err = put_user(byte, (unsigned char __user *)buf);
  50. break;
  51. case 2:
  52. err = put_user(word, (unsigned short __user *)buf);
  53. break;
  54. case 4:
  55. err = put_user(dword, (unsigned int __user *)buf);
  56. break;
  57. }
  58. pci_dev_put(dev);
  59. return err;
  60. error:
  61. /* ??? XFree86 doesn't even check the return value. They
  62. just look for 0xffffffff in the output, since that's what
  63. they get instead of a machine check on x86. */
  64. switch (len) {
  65. case 1:
  66. put_user(-1, (unsigned char __user *)buf);
  67. break;
  68. case 2:
  69. put_user(-1, (unsigned short __user *)buf);
  70. break;
  71. case 4:
  72. put_user(-1, (unsigned int __user *)buf);
  73. break;
  74. }
  75. pci_dev_put(dev);
  76. return err;
  77. }
  78. SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,
  79. unsigned long, off, unsigned long, len, void __user *, buf)
  80. {
  81. struct pci_dev *dev;
  82. u8 byte;
  83. u16 word;
  84. u32 dword;
  85. int err = 0;
  86. if (!capable(CAP_SYS_ADMIN) ||
  87. security_locked_down(LOCKDOWN_PCI_ACCESS))
  88. return -EPERM;
  89. dev = pci_get_domain_bus_and_slot(0, bus, dfn);
  90. if (!dev)
  91. return -ENODEV;
  92. switch (len) {
  93. case 1:
  94. err = get_user(byte, (u8 __user *)buf);
  95. if (err)
  96. break;
  97. err = pci_user_write_config_byte(dev, off, byte);
  98. if (err)
  99. err = -EIO;
  100. break;
  101. case 2:
  102. err = get_user(word, (u16 __user *)buf);
  103. if (err)
  104. break;
  105. err = pci_user_write_config_word(dev, off, word);
  106. if (err)
  107. err = -EIO;
  108. break;
  109. case 4:
  110. err = get_user(dword, (u32 __user *)buf);
  111. if (err)
  112. break;
  113. err = pci_user_write_config_dword(dev, off, dword);
  114. if (err)
  115. err = -EIO;
  116. break;
  117. default:
  118. err = -EINVAL;
  119. break;
  120. }
  121. pci_dev_put(dev);
  122. return err;
  123. }