cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

drm_privacy_screen_x86.c (2487B)

      1// SPDX-License-Identifier: MIT
      2/*
      3 * Copyright (C) 2020 Red Hat, Inc.
      4 *
      5 * Authors:
      6 * Hans de Goede <hdegoede@redhat.com>
      7 */
      8
      9#include <linux/acpi.h>
     10#include <drm/drm_privacy_screen_machine.h>
     11
     12#ifdef CONFIG_X86
     13static struct drm_privacy_screen_lookup arch_lookup;
     14
     15struct arch_init_data {
     16	struct drm_privacy_screen_lookup lookup;
     17	bool (*detect)(void);
     18};
     19
     20#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
     21static acpi_status __init acpi_set_handle(acpi_handle handle, u32 level,
     22					  void *context, void **return_value)
     23{
     24	*(acpi_handle *)return_value = handle;
     25	return AE_CTRL_TERMINATE;
     26}
     27
     28static bool __init detect_thinkpad_privacy_screen(void)
     29{
     30	union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
     31	struct acpi_object_list args = { .count = 1, .pointer = &obj, };
     32	acpi_handle ec_handle = NULL;
     33	unsigned long long output;
     34	acpi_status status;
     35
     36	if (acpi_disabled)
     37		return false;
     38
     39	/* Get embedded-controller handle */
     40	status = acpi_get_devices("PNP0C09", acpi_set_handle, NULL, &ec_handle);
     41	if (ACPI_FAILURE(status) || !ec_handle)
     42		return false;
     43
     44	/* And call the privacy-screen get-status method */
     45	status = acpi_evaluate_integer(ec_handle, "HKEY.GSSS", &args, &output);
     46	if (ACPI_FAILURE(status))
     47		return false;
     48
     49	return (output & 0x10000) ? true : false;
     50}
     51#endif
     52
     53#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
     54static bool __init detect_chromeos_privacy_screen(void)
     55{
     56	return acpi_dev_present("GOOG0010", NULL, -1);
     57}
     58#endif
     59
     60static const struct arch_init_data arch_init_data[] __initconst = {
     61#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
     62	{
     63		.lookup = {
     64			.dev_id = NULL,
     65			.con_id = NULL,
     66			.provider = "privacy_screen-thinkpad_acpi",
     67		},
     68		.detect = detect_thinkpad_privacy_screen,
     69	},
     70#endif
     71#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
     72	{
     73		.lookup = {
     74			.dev_id = NULL,
     75			.con_id = NULL,
     76			.provider = "privacy_screen-GOOG0010:00",
     77		},
     78		.detect = detect_chromeos_privacy_screen,
     79	},
     80#endif
     81};
     82
     83void __init drm_privacy_screen_lookup_init(void)
     84{
     85	int i;
     86
     87	for (i = 0; i < ARRAY_SIZE(arch_init_data); i++) {
     88		if (!arch_init_data[i].detect())
     89			continue;
     90
     91		pr_info("Found '%s' privacy-screen provider\n",
     92			arch_init_data[i].lookup.provider);
     93
     94		/* Make a copy because arch_init_data is __initconst */
     95		arch_lookup = arch_init_data[i].lookup;
     96		drm_privacy_screen_lookup_add(&arch_lookup);
     97		break;
     98	}
     99}
    100
    101void drm_privacy_screen_lookup_exit(void)
    102{
    103	if (arch_lookup.provider)
    104		drm_privacy_screen_lookup_remove(&arch_lookup);
    105}
    106#endif /* ifdef CONFIG_X86 */