cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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chromeos_pstore.c (3285B)

      1// SPDX-License-Identifier: GPL-2.0
      2// Driver to instantiate Chromebook ramoops device.
      3//
      4// Copyright (C) 2013 Google, Inc.
      5
      6#include <linux/acpi.h>
      7#include <linux/dmi.h>
      8#include <linux/module.h>
      9#include <linux/platform_device.h>
     10#include <linux/pstore_ram.h>
     11
     12static const struct dmi_system_id chromeos_pstore_dmi_table[] __initconst = {
     13	{
     14		/*
     15		 * Today all Chromebooks/boxes ship with Google_* as version and
     16		 * coreboot as bios vendor. No other systems with this
     17		 * combination are known to date.
     18		 */
     19		.matches = {
     20			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
     21			DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
     22		},
     23	},
     24	{
     25		/* x86-alex, the first Samsung Chromebook. */
     26		.matches = {
     27			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
     28			DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
     29		},
     30	},
     31	{
     32		/* x86-mario, the Cr-48 pilot device from Google. */
     33		.matches = {
     34			DMI_MATCH(DMI_SYS_VENDOR, "IEC"),
     35			DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
     36		},
     37	},
     38	{
     39		/* x86-zgb, the first Acer Chromebook. */
     40		.matches = {
     41			DMI_MATCH(DMI_SYS_VENDOR, "ACER"),
     42			DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
     43		},
     44	},
     45	{ }
     46};
     47MODULE_DEVICE_TABLE(dmi, chromeos_pstore_dmi_table);
     48
     49/*
     50 * On x86 chromebooks/boxes, the firmware will keep the legacy VGA memory
     51 * range untouched across reboots, so we use that to store our pstore
     52 * contents for panic logs, etc.
     53 */
     54static struct ramoops_platform_data chromeos_ramoops_data = {
     55	.mem_size	= 0x100000,
     56	.mem_address	= 0xf00000,
     57	.record_size	= 0x40000,
     58	.console_size	= 0x20000,
     59	.ftrace_size	= 0x20000,
     60	.pmsg_size	= 0x20000,
     61	.max_reason	= KMSG_DUMP_OOPS,
     62};
     63
     64static struct platform_device chromeos_ramoops = {
     65	.name = "ramoops",
     66	.dev = {
     67		.platform_data = &chromeos_ramoops_data,
     68	},
     69};
     70
     71#ifdef CONFIG_ACPI
     72static const struct acpi_device_id cros_ramoops_acpi_match[] = {
     73	{ "GOOG9999", 0 },
     74	{ }
     75};
     76MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);
     77
     78static struct platform_driver chromeos_ramoops_acpi = {
     79	.driver		= {
     80		.name	= "chromeos_pstore",
     81		.acpi_match_table = ACPI_PTR(cros_ramoops_acpi_match),
     82	},
     83};
     84
     85static int __init chromeos_probe_acpi(struct platform_device *pdev)
     86{
     87	struct resource *res;
     88	resource_size_t len;
     89
     90	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
     91	if (!res)
     92		return -ENOMEM;
     93
     94	len = resource_size(res);
     95	if (!res->start || !len)
     96		return -ENOMEM;
     97
     98	pr_info("chromeos ramoops using acpi device.\n");
     99
    100	chromeos_ramoops_data.mem_size = len;
    101	chromeos_ramoops_data.mem_address = res->start;
    102
    103	return 0;
    104}
    105
    106static bool __init chromeos_check_acpi(void)
    107{
    108	if (!platform_driver_probe(&chromeos_ramoops_acpi, chromeos_probe_acpi))
    109		return true;
    110	return false;
    111}
    112#else
    113static inline bool chromeos_check_acpi(void) { return false; }
    114#endif
    115
    116static int __init chromeos_pstore_init(void)
    117{
    118	bool acpi_dev_found;
    119
    120	/* First check ACPI for non-hardcoded values from firmware. */
    121	acpi_dev_found = chromeos_check_acpi();
    122
    123	if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
    124		return platform_device_register(&chromeos_ramoops);
    125
    126	return -ENODEV;
    127}
    128
    129static void __exit chromeos_pstore_exit(void)
    130{
    131	platform_device_unregister(&chromeos_ramoops);
    132}
    133
    134module_init(chromeos_pstore_init);
    135module_exit(chromeos_pstore_exit);
    136
    137MODULE_DESCRIPTION("ChromeOS pstore module");
    138MODULE_LICENSE("GPL v2");