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}