drivers/platform/x86/intel/ifs/core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright(c) 2022 Intel Corporation. */
   3
   4 #include <linux/module.h>
   5 #include <linux/kdev_t.h>
   6 #include <linux/semaphore.h>
   7
   8 #include <asm/cpu_device_id.h>
   9
  10 #include "ifs.h"
  11
  12 #define X86_MATCH(model)                                \
  13         X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6,    \
  14                 INTEL_FAM6_##model, X86_FEATURE_CORE_CAPABILITIES, NULL)
  15
  16 static const struct x86_cpu_id ifs_cpu_ids[] __initconst = {
  17         X86_MATCH(SAPPHIRERAPIDS_X),
  18         {}
  19 };
  20 MODULE_DEVICE_TABLE(x86cpu, ifs_cpu_ids);
  21
  22 static struct ifs_device ifs_device = {
  23         .data = {
  24                 .integrity_cap_bit = MSR_INTEGRITY_CAPS_PERIODIC_BIST_BIT,
  25         },
  26         .misc = {
  27                 .name = "intel_ifs_0",
  28                 .nodename = "intel_ifs/0",
  29                 .minor = MISC_DYNAMIC_MINOR,
  30         },
  31 };
  32
  33 static int __init ifs_init(void)
  34 {
  35         const struct x86_cpu_id *m;
  36         u64 msrval;
  37
  38         m = x86_match_cpu(ifs_cpu_ids);
  39         if (!m)
  40                 return -ENODEV;
  41
  42         if (rdmsrl_safe(MSR_IA32_CORE_CAPS, &msrval))
  43                 return -ENODEV;
  44
  45         if (!(msrval & MSR_IA32_CORE_CAPS_INTEGRITY_CAPS))
  46                 return -ENODEV;
  47
  48         if (rdmsrl_safe(MSR_INTEGRITY_CAPS, &msrval))
  49                 return -ENODEV;
  50
  51         ifs_device.misc.groups = ifs_get_groups();
  52
  53         if ((msrval & BIT(ifs_device.data.integrity_cap_bit)) &&
  54             !misc_register(&ifs_device.misc)) {
  55                 down(&ifs_sem);
  56                 ifs_load_firmware(ifs_device.misc.this_device);
  57                 up(&ifs_sem);
  58                 return 0;
  59         }
  60
  61         return -ENODEV;
  62 }
  63
  64 static void __exit ifs_exit(void)
  65 {
  66         misc_deregister(&ifs_device.misc);
  67 }
  68
  69 module_init(ifs_init);
  70 module_exit(ifs_exit);
  71
  72 MODULE_LICENSE("GPL");
  73 MODULE_DESCRIPTION("Intel In Field Scan (IFS) device");