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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agdi.c (2503B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * This file implements handling of
      4 * Arm Generic Diagnostic Dump and Reset Interface table (AGDI)
      5 *
      6 * Copyright (c) 2022, Ampere Computing LLC
      7 */
      8
      9#define pr_fmt(fmt) "ACPI: AGDI: " fmt
     10
     11#include <linux/acpi.h>
     12#include <linux/acpi_agdi.h>
     13#include <linux/arm_sdei.h>
     14#include <linux/io.h>
     15#include <linux/kernel.h>
     16#include <linux/platform_device.h>
     17
     18struct agdi_data {
     19	int sdei_event;
     20};
     21
     22static int agdi_sdei_handler(u32 sdei_event, struct pt_regs *regs, void *arg)
     23{
     24	nmi_panic(regs, "Arm Generic Diagnostic Dump and Reset SDEI event issued");
     25	return 0;
     26}
     27
     28static int agdi_sdei_probe(struct platform_device *pdev,
     29			   struct agdi_data *adata)
     30{
     31	int err;
     32
     33	err = sdei_event_register(adata->sdei_event, agdi_sdei_handler, pdev);
     34	if (err) {
     35		dev_err(&pdev->dev, "Failed to register for SDEI event %d",
     36			adata->sdei_event);
     37		return err;
     38	}
     39
     40	err = sdei_event_enable(adata->sdei_event);
     41	if (err)  {
     42		sdei_event_unregister(adata->sdei_event);
     43		dev_err(&pdev->dev, "Failed to enable event %d\n",
     44			adata->sdei_event);
     45		return err;
     46	}
     47
     48	return 0;
     49}
     50
     51static int agdi_probe(struct platform_device *pdev)
     52{
     53	struct agdi_data *adata = dev_get_platdata(&pdev->dev);
     54
     55	if (!adata)
     56		return -EINVAL;
     57
     58	return agdi_sdei_probe(pdev, adata);
     59}
     60
     61static int agdi_remove(struct platform_device *pdev)
     62{
     63	struct agdi_data *adata = dev_get_platdata(&pdev->dev);
     64	int err, i;
     65
     66	err = sdei_event_disable(adata->sdei_event);
     67	if (err)
     68		return err;
     69
     70	for (i = 0; i < 3; i++) {
     71		err = sdei_event_unregister(adata->sdei_event);
     72		if (err != -EINPROGRESS)
     73			break;
     74
     75		schedule();
     76	}
     77
     78	return err;
     79}
     80
     81static struct platform_driver agdi_driver = {
     82	.driver = {
     83		.name = "agdi",
     84	},
     85	.probe = agdi_probe,
     86	.remove = agdi_remove,
     87};
     88
     89void __init acpi_agdi_init(void)
     90{
     91	struct acpi_table_agdi *agdi_table;
     92	struct agdi_data pdata;
     93	struct platform_device *pdev;
     94	acpi_status status;
     95
     96	status = acpi_get_table(ACPI_SIG_AGDI, 0,
     97				(struct acpi_table_header **) &agdi_table);
     98	if (ACPI_FAILURE(status))
     99		return;
    100
    101	if (agdi_table->flags & ACPI_AGDI_SIGNALING_MODE) {
    102		pr_warn("Interrupt signaling is not supported");
    103		goto err_put_table;
    104	}
    105
    106	pdata.sdei_event = agdi_table->sdei_event;
    107
    108	pdev = platform_device_register_data(NULL, "agdi", 0, &pdata, sizeof(pdata));
    109	if (IS_ERR(pdev))
    110		goto err_put_table;
    111
    112	if (platform_driver_register(&agdi_driver))
    113		platform_device_unregister(pdev);
    114
    115err_put_table:
    116	acpi_put_table((struct acpi_table_header *)agdi_table);
    117}