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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mce.c (2708B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * NFIT - Machine Check Handler
      4 *
      5 * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
      6 */
      7#include <linux/notifier.h>
      8#include <linux/acpi.h>
      9#include <linux/nd.h>
     10#include <asm/mce.h>
     11#include "nfit.h"
     12
     13static int nfit_handle_mce(struct notifier_block *nb, unsigned long val,
     14			void *data)
     15{
     16	struct mce *mce = (struct mce *)data;
     17	struct acpi_nfit_desc *acpi_desc;
     18	struct nfit_spa *nfit_spa;
     19
     20	/* We only care about uncorrectable memory errors */
     21	if (!mce_is_memory_error(mce) || mce_is_correctable(mce))
     22		return NOTIFY_DONE;
     23
     24	/* Verify the address reported in the MCE is valid. */
     25	if (!mce_usable_address(mce))
     26		return NOTIFY_DONE;
     27
     28	/*
     29	 * mce->addr contains the physical addr accessed that caused the
     30	 * machine check. We need to walk through the list of NFITs, and see
     31	 * if any of them matches that address, and only then start a scrub.
     32	 */
     33	mutex_lock(&acpi_desc_lock);
     34	list_for_each_entry(acpi_desc, &acpi_descs, list) {
     35		unsigned int align = 1UL << MCI_MISC_ADDR_LSB(mce->misc);
     36		struct device *dev = acpi_desc->dev;
     37		int found_match = 0;
     38
     39		mutex_lock(&acpi_desc->init_mutex);
     40		list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
     41			struct acpi_nfit_system_address *spa = nfit_spa->spa;
     42
     43			if (nfit_spa_type(spa) != NFIT_SPA_PM)
     44				continue;
     45			/* find the spa that covers the mce addr */
     46			if (spa->address > mce->addr)
     47				continue;
     48			if ((spa->address + spa->length - 1) < mce->addr)
     49				continue;
     50			found_match = 1;
     51			dev_dbg(dev, "addr in SPA %d (0x%llx, 0x%llx)\n",
     52				spa->range_index, spa->address, spa->length);
     53			/*
     54			 * We can break at the first match because we're going
     55			 * to rescan all the SPA ranges. There shouldn't be any
     56			 * aliasing anyway.
     57			 */
     58			break;
     59		}
     60		mutex_unlock(&acpi_desc->init_mutex);
     61
     62		if (!found_match)
     63			continue;
     64
     65		/* If this fails due to an -ENOMEM, there is little we can do */
     66		nvdimm_bus_add_badrange(acpi_desc->nvdimm_bus,
     67				ALIGN_DOWN(mce->addr, align), align);
     68		nvdimm_region_notify(nfit_spa->nd_region,
     69				NVDIMM_REVALIDATE_POISON);
     70
     71		if (acpi_desc->scrub_mode == HW_ERROR_SCRUB_ON) {
     72			/*
     73			 * We can ignore an -EBUSY here because if an ARS is
     74			 * already in progress, just let that be the last
     75			 * authoritative one
     76			 */
     77			acpi_nfit_ars_rescan(acpi_desc, 0);
     78		}
     79		mce->kflags |= MCE_HANDLED_NFIT;
     80		break;
     81	}
     82
     83	mutex_unlock(&acpi_desc_lock);
     84	return NOTIFY_DONE;
     85}
     86
     87static struct notifier_block nfit_mce_dec = {
     88	.notifier_call	= nfit_handle_mce,
     89	.priority	= MCE_PRIO_NFIT,
     90};
     91
     92void nfit_mce_register(void)
     93{
     94	mce_register_decode_chain(&nfit_mce_dec);
     95}
     96
     97void nfit_mce_unregister(void)
     98{
     99	mce_unregister_decode_chain(&nfit_mce_dec);
    100}