// SPDX-License-Identifier: GPL-2.0-only
/*
 * Bridge between MCE and APEI
 *
 * On some machine, corrected memory errors are reported via APEI
 * generic hardware error source (GHES) instead of corrected Machine
 * Check. These corrected memory errors can be reported to user space
 * through /dev/mcelog via faking a corrected Machine Check, so that
 * the error memory page can be offlined by /sbin/mcelog if the error
 * count for one page is beyond the threshold.
 *
 * For fatal MCE, save MCE record into persistent storage via ERST, so
 * that the MCE record can be logged after reboot via ERST.
 *
 * Copyright 2010 Intel Corp.
 *   Author: Huang Ying <ying.huang@intel.com>
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/cper.h>
#include <acpi/apei.h>
#include <acpi/ghes.h>
#include <asm/mce.h>

#include "internal.h"

void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
{
        struct mce m;

        if (!(mem_err->validation_bits & CPER_MEM_VALID_PA))
                return;

        mce_setup(&m);
        m.bank = -1;
        /* Fake a memory read error with unknown channel */
        m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | MCI_STATUS_MISCV | 0x9f;
        m.misc = (MCI_MISC_ADDR_PHYS << 6) | PAGE_SHIFT;

        if (severity >= GHES_SEV_RECOVERABLE)
                m.status |= MCI_STATUS_UC;

        if (severity >= GHES_SEV_PANIC) {
                m.status |= MCI_STATUS_PCC;
                m.tsc = rdtsc();
        }

        m.addr = mem_err->physical_addr;
        mce_log(&m);
}
EXPORT_SYMBOL_GPL(apei_mce_report_mem_error);

int apei_smca_report_x86_error(struct cper_ia_proc_ctx *ctx_info, u64 lapic_id)
{
        const u64 *i_mce = ((const u64 *) (ctx_info + 1));
        unsigned int cpu;
        struct mce m;

        if (!boot_cpu_has(X86_FEATURE_SMCA))
                return -EINVAL;

        /*
         * The starting address of the register array extracted from BERT must
         * match with the first expected register in the register layout of
         * SMCA address space. This address corresponds to banks's MCA_STATUS
         * register.
         *
         * Match any MCi_STATUS register by turning off bank numbers.
         */
        if ((ctx_info->msr_addr & MSR_AMD64_SMCA_MC0_STATUS) !=
                                  MSR_AMD64_SMCA_MC0_STATUS)
                return -EINVAL;

        /*
         * The register array size must be large enough to include all the
         * SMCA registers which need to be extracted.
         *
         * The number of registers in the register array is determined by
         * Register Array Size/8 as defined in UEFI spec v2.8, sec N.2.4.2.2.
         * The register layout is fixed and currently the raw data in the
         * register array includes 6 SMCA registers which the kernel can
         * extract.
         */
        if (ctx_info->reg_arr_size < 48)
                return -EINVAL;

        mce_setup(&m);

        m.extcpu = -1;
        m.socketid = -1;

        for_each_possible_cpu(cpu) {
                if (cpu_data(cpu).initial_apicid == lapic_id) {
                        m.extcpu = cpu;
                        m.socketid = cpu_data(m.extcpu).phys_proc_id;
                        break;
                }
        }

        m.apicid = lapic_id;
        m.bank = (ctx_info->msr_addr >> 4) & 0xFF;
        m.status = *i_mce;
        m.addr = *(i_mce + 1);
        m.misc = *(i_mce + 2);
        /* Skipping MCA_CONFIG */
        m.ipid = *(i_mce + 4);
        m.synd = *(i_mce + 5);

        mce_log(&m);

        return 0;
}

#define CPER_CREATOR_MCE                                                \
        GUID_INIT(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,   \
                  0x64, 0x90, 0xb8, 0x9d)
#define CPER_SECTION_TYPE_MCE                                           \
        GUID_INIT(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,   \
                  0x04, 0x4a, 0x38, 0xfc)

/*
 * CPER specification (in UEFI specification 2.3 appendix N) requires
 * byte-packed.
 */
struct cper_mce_record {
        struct cper_record_header hdr;
        struct cper_section_descriptor sec_hdr;
        struct mce mce;
} __packed;

int apei_write_mce(struct mce *m)
{
        struct cper_mce_record rcd;

        memset(&rcd, 0, sizeof(rcd));
        memcpy(rcd.hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
        rcd.hdr.revision = CPER_RECORD_REV;
        rcd.hdr.signature_end = CPER_SIG_END;
        rcd.hdr.section_count = 1;
        rcd.hdr.error_severity = CPER_SEV_FATAL;
        /* timestamp, platform_id, partition_id are all invalid */
        rcd.hdr.validation_bits = 0;
        rcd.hdr.record_length = sizeof(rcd);
        rcd.hdr.creator_id = CPER_CREATOR_MCE;
        rcd.hdr.notification_type = CPER_NOTIFY_MCE;
        rcd.hdr.record_id = cper_next_record_id();
        rcd.hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;

        rcd.sec_hdr.section_offset = (void *)&rcd.mce - (void *)&rcd;
        rcd.sec_hdr.section_length = sizeof(rcd.mce);
        rcd.sec_hdr.revision = CPER_SEC_REV;
        /* fru_id and fru_text is invalid */
        rcd.sec_hdr.validation_bits = 0;
        rcd.sec_hdr.flags = CPER_SEC_PRIMARY;
        rcd.sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
        rcd.sec_hdr.section_severity = CPER_SEV_FATAL;

        memcpy(&rcd.mce, m, sizeof(*m));

        return erst_write(&rcd.hdr);
}

ssize_t apei_read_mce(struct mce *m, u64 *record_id)
{
        struct cper_mce_record rcd;
        int rc, pos;

        rc = erst_get_record_id_begin(&pos);
        if (rc)
                return rc;
retry:
        rc = erst_get_record_id_next(&pos, record_id);
        if (rc)
                goto out;
        /* no more record */
        if (*record_id == APEI_ERST_INVALID_RECORD_ID)
                goto out;
        rc = erst_read(*record_id, &rcd.hdr, sizeof(rcd));
        /* someone else has cleared the record, try next one */
        if (rc == -ENOENT)
                goto retry;
        else if (rc < 0)
                goto out;
        /* try to skip other type records in storage */
        else if (rc != sizeof(rcd) ||
                 !guid_equal(&rcd.hdr.creator_id, &CPER_CREATOR_MCE))
                goto retry;
        memcpy(m, &rcd.mce, sizeof(*m));
        rc = sizeof(*m);
out:
        erst_get_record_id_end();

        return rc;
}

/* Check whether there is record in ERST */
int apei_check_mce(void)
{
        return erst_get_record_count();
}

int apei_clear_mce(u64 record_id)
{
        return erst_clear(record_id);
}