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    Subject[PATCH V4 2/9] cxl/mem: Read, trace, and clear events on driver load
    Date
    From: Ira Weiny <ira.weiny@intel.com>

    CXL devices have multiple event logs which can be queried for CXL event
    records. Devices are required to support the storage of at least one
    event record in each event log type.

    Devices track event log overflow by incrementing a counter and tracking
    the time of the first and last overflow event seen.

    Software queries events via the Get Event Record mailbox command; CXL
    rev 3.0 section 8.2.9.2.2 and clears events via CXL rev 3.0 section
    8.2.9.2.3 Clear Event Records mailbox command.

    If the result of negotiating CXL Error Reporting Control is OS control,
    read and clear all event logs on driver load.

    Ensure a clean slate of events by reading and clearing the events on
    driver load.

    The status register is not used because a device may continue to trigger
    events and the only requirement is to empty the log at least once. This
    allows for the required transition from empty to non-empty for interrupt
    generation. Handling of interrupts is in a follow on patch.

    The device can return up to 1MB worth of event records per query.
    Allocate a shared large buffer to handle the max number of records based
    on the mailbox payload size.

    This patch traces a raw event record and leaves specific event record
    type tracing to subsequent patches. Macros are created to aid in
    tracing the common CXL Event header fields.

    Each record is cleared explicitly. A clear all bit is specified but is
    only valid when the log overflows.

    Signed-off-by: Ira Weiny <ira.weiny@intel.com>

    ---
    Changes from V3:
    Dan
    Split off _OSC pcie bits
    Use existing style for host bridge flag in that
    patch
    Clean up event processing loop
    Use dev_err_ratelimited()
    Clean up version change log
    Delete 'EVENT LOG OVERFLOW'
    Remove cxl_clear_event_logs()
    Add comment for native cxl control
    Fail driver load on event buf allocation failure
    Comment why events are not processed without _OSC flag
    ---
    drivers/cxl/core/mbox.c | 136 +++++++++++++++++++++++++++++++++++++++
    drivers/cxl/core/trace.h | 120 ++++++++++++++++++++++++++++++++++
    drivers/cxl/cxl.h | 12 ++++
    drivers/cxl/cxlmem.h | 84 ++++++++++++++++++++++++
    drivers/cxl/pci.c | 40 ++++++++++++
    5 files changed, 392 insertions(+)

    diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
    index b03fba212799..9fb327370e08 100644
    --- a/drivers/cxl/core/mbox.c
    +++ b/drivers/cxl/core/mbox.c
    @@ -8,6 +8,7 @@
    #include <cxl.h>

    #include "core.h"
    +#include "trace.h"

    static bool cxl_raw_allow_all;

    @@ -717,6 +718,140 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
    }
    EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL);

    +static int cxl_clear_event_record(struct cxl_dev_state *cxlds,
    + enum cxl_event_log_type log,
    + struct cxl_get_event_payload *get_pl)
    +{
    + struct cxl_mbox_clear_event_payload payload = {
    + .event_log = log,
    + };
    + u16 total = le16_to_cpu(get_pl->record_count);
    + u8 max_handles = CXL_CLEAR_EVENT_MAX_HANDLES;
    + size_t pl_size = sizeof(payload);
    + struct cxl_mbox_cmd mbox_cmd;
    + u16 cnt;
    + int rc;
    + int i;
    +
    + /* Payload size may limit the max handles */
    + if (pl_size > cxlds->payload_size) {
    + max_handles = CXL_CLEAR_EVENT_LIMIT_HANDLES(cxlds->payload_size);
    + pl_size = cxlds->payload_size;
    + }
    +
    + mbox_cmd = (struct cxl_mbox_cmd) {
    + .opcode = CXL_MBOX_OP_CLEAR_EVENT_RECORD,
    + .payload_in = &payload,
    + .size_in = pl_size,
    + };
    +
    + /*
    + * Clear Event Records uses u8 for the handle cnt while Get Event
    + * Record can return up to 0xffff records.
    + */
    + i = 0;
    + for (cnt = 0; cnt < total; cnt++) {
    + payload.handle[i++] = get_pl->records[cnt].hdr.handle;
    + dev_dbg(cxlds->dev, "Event log '%d': Clearing %u\n",
    + log, le16_to_cpu(payload.handle[i]));
    +
    + if (i == max_handles) {
    + payload.nr_recs = i;
    + rc = cxl_internal_send_cmd(cxlds, &mbox_cmd);
    + if (rc)
    + return rc;
    + i = 0;
    + }
    + }
    +
    + /* Clear what is left if any */
    + if (i) {
    + payload.nr_recs = i;
    + rc = cxl_internal_send_cmd(cxlds, &mbox_cmd);
    + if (rc)
    + return rc;
    + }
    +
    + return 0;
    +}
    +
    +static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
    + enum cxl_event_log_type type)
    +{
    + struct cxl_get_event_payload *payload;
    + struct cxl_mbox_cmd mbox_cmd;
    + u8 log_type = type;
    + u16 nr_rec;
    +
    + mutex_lock(&cxlds->event.log_lock);
    + payload = cxlds->event.buf;
    +
    + mbox_cmd = (struct cxl_mbox_cmd) {
    + .opcode = CXL_MBOX_OP_GET_EVENT_RECORD,
    + .payload_in = &log_type,
    + .size_in = sizeof(log_type),
    + .payload_out = payload,
    + .size_out = cxlds->payload_size,
    + .min_out = struct_size(payload, records, 0),
    + };
    +
    + do {
    + int rc, i;
    +
    + rc = cxl_internal_send_cmd(cxlds, &mbox_cmd);
    + if (rc) {
    + dev_err_ratelimited(cxlds->dev, "Event log '%d': Failed to query event records : %d",
    + type, rc);
    + break;
    + }
    +
    + nr_rec = le16_to_cpu(payload->record_count);
    + if (!nr_rec)
    + break;
    +
    + for (i = 0; i < nr_rec; i++)
    + trace_cxl_generic_event(cxlds->dev, type,
    + &payload->records[i]);
    +
    + if (payload->flags & CXL_GET_EVENT_FLAG_OVERFLOW)
    + trace_cxl_overflow(cxlds->dev, type, payload);
    +
    + rc = cxl_clear_event_record(cxlds, type, payload);
    + if (rc) {
    + dev_err_ratelimited(cxlds->dev, "Event log '%d': Failed to clear events : %d",
    + type, rc);
    + break;
    + }
    + } while (nr_rec);
    +
    + mutex_unlock(&cxlds->event.log_lock);
    +}
    +
    +/**
    + * cxl_mem_get_event_records - Get Event Records from the device
    + * @cxlds: The device data for the operation
    + *
    + * Retrieve all event records available on the device, report them as trace
    + * events, and clear them.
    + *
    + * See CXL rev 3.0 @8.2.9.2.2 Get Event Records
    + * See CXL rev 3.0 @8.2.9.2.3 Clear Event Records
    + */
    +void cxl_mem_get_event_records(struct cxl_dev_state *cxlds, u32 status)
    +{
    + dev_dbg(cxlds->dev, "Reading event logs: %x\n", status);
    +
    + if (status & CXLDEV_EVENT_STATUS_FATAL)
    + cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_FATAL);
    + if (status & CXLDEV_EVENT_STATUS_FAIL)
    + cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_FAIL);
    + if (status & CXLDEV_EVENT_STATUS_WARN)
    + cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_WARN);
    + if (status & CXLDEV_EVENT_STATUS_INFO)
    + cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_INFO);
    +}
    +EXPORT_SYMBOL_NS_GPL(cxl_mem_get_event_records, CXL);
    +
    /**
    * cxl_mem_get_partition_info - Get partition info
    * @cxlds: The device data for the operation
    @@ -868,6 +1003,7 @@ struct cxl_dev_state *cxl_dev_state_create(struct device *dev)
    }

    mutex_init(&cxlds->mbox_mutex);
    + mutex_init(&cxlds->event.log_lock);
    cxlds->dev = dev;

    return cxlds;
    diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
    index 20ca2fe2ca8e..6898212fcb47 100644
    --- a/drivers/cxl/core/trace.h
    +++ b/drivers/cxl/core/trace.h
    @@ -6,7 +6,9 @@
    #if !defined(_CXL_EVENTS_H) || defined(TRACE_HEADER_MULTI_READ)
    #define _CXL_EVENTS_H

    +#include <asm-generic/unaligned.h>
    #include <cxl.h>
    +#include <cxlmem.h>
    #include <linux/tracepoint.h>

    #define CXL_RAS_UC_CACHE_DATA_PARITY BIT(0)
    @@ -103,6 +105,124 @@ TRACE_EVENT(cxl_aer_correctable_error,
    )
    );

    +#include <linux/tracepoint.h>
    +
    +#define cxl_event_log_type_str(type) \
    + __print_symbolic(type, \
    + { CXL_EVENT_TYPE_INFO, "Informational" }, \
    + { CXL_EVENT_TYPE_WARN, "Warning" }, \
    + { CXL_EVENT_TYPE_FAIL, "Failure" }, \
    + { CXL_EVENT_TYPE_FATAL, "Fatal" })
    +
    +TRACE_EVENT(cxl_overflow,
    +
    + TP_PROTO(const struct device *dev, enum cxl_event_log_type log,
    + struct cxl_get_event_payload *payload),
    +
    + TP_ARGS(dev, log, payload),
    +
    + TP_STRUCT__entry(
    + __string(dev_name, dev_name(dev))
    + __field(int, log)
    + __field(u64, first_ts)
    + __field(u64, last_ts)
    + __field(u16, count)
    + ),
    +
    + TP_fast_assign(
    + __assign_str(dev_name, dev_name(dev));
    + __entry->log = log;
    + __entry->count = le16_to_cpu(payload->overflow_err_count);
    + __entry->first_ts = le64_to_cpu(payload->first_overflow_timestamp);
    + __entry->last_ts = le64_to_cpu(payload->last_overflow_timestamp);
    + ),
    +
    + TP_printk("%s: log=%s : %u records from %llu to %llu",
    + __get_str(dev_name), cxl_event_log_type_str(__entry->log),
    + __entry->count, __entry->first_ts, __entry->last_ts)
    +
    +);
    +
    +/*
    + * Common Event Record Format
    + * CXL 3.0 section 8.2.9.2.1; Table 8-42
    + */
    +#define CXL_EVENT_RECORD_FLAG_PERMANENT BIT(2)
    +#define CXL_EVENT_RECORD_FLAG_MAINT_NEEDED BIT(3)
    +#define CXL_EVENT_RECORD_FLAG_PERF_DEGRADED BIT(4)
    +#define CXL_EVENT_RECORD_FLAG_HW_REPLACE BIT(5)
    +#define show_hdr_flags(flags) __print_flags(flags, " | ", \
    + { CXL_EVENT_RECORD_FLAG_PERMANENT, "PERMANENT_CONDITION" }, \
    + { CXL_EVENT_RECORD_FLAG_MAINT_NEEDED, "MAINTENANCE_NEEDED" }, \
    + { CXL_EVENT_RECORD_FLAG_PERF_DEGRADED, "PERFORMANCE_DEGRADED" }, \
    + { CXL_EVENT_RECORD_FLAG_HW_REPLACE, "HARDWARE_REPLACEMENT_NEEDED" } \
    +)
    +
    +/*
    + * Define macros for the common header of each CXL event.
    + *
    + * Tracepoints using these macros must do 3 things:
    + *
    + * 1) Add CXL_EVT_TP_entry to TP_STRUCT__entry
    + * 2) Use CXL_EVT_TP_fast_assign within TP_fast_assign;
    + * pass the dev, log, and CXL event header
    + * 3) Use CXL_EVT_TP_printk() instead of TP_printk()
    + *
    + * See the generic_event tracepoint as an example.
    + */
    +#define CXL_EVT_TP_entry \
    + __string(dev_name, dev_name(dev)) \
    + __field(int, log) \
    + __field_struct(uuid_t, hdr_uuid) \
    + __field(u32, hdr_flags) \
    + __field(u16, hdr_handle) \
    + __field(u16, hdr_related_handle) \
    + __field(u64, hdr_timestamp) \
    + __field(u8, hdr_length) \
    + __field(u8, hdr_maint_op_class)
    +
    +#define CXL_EVT_TP_fast_assign(dev, l, hdr) \
    + __assign_str(dev_name, dev_name(dev)); \
    + __entry->log = (l); \
    + memcpy(&__entry->hdr_uuid, &(hdr).id, sizeof(uuid_t)); \
    + __entry->hdr_length = (hdr).length; \
    + __entry->hdr_flags = get_unaligned_le24((hdr).flags); \
    + __entry->hdr_handle = le16_to_cpu((hdr).handle); \
    + __entry->hdr_related_handle = le16_to_cpu((hdr).related_handle); \
    + __entry->hdr_timestamp = le64_to_cpu((hdr).timestamp); \
    + __entry->hdr_maint_op_class = (hdr).maint_op_class
    +
    +#define CXL_EVT_TP_printk(fmt, ...) \
    + TP_printk("%s log=%s : time=%llu uuid=%pUb len=%d flags='%s' " \
    + "handle=%x related_handle=%x maint_op_class=%u" \
    + " : " fmt, \
    + __get_str(dev_name), cxl_event_log_type_str(__entry->log), \
    + __entry->hdr_timestamp, &__entry->hdr_uuid, __entry->hdr_length,\
    + show_hdr_flags(__entry->hdr_flags), __entry->hdr_handle, \
    + __entry->hdr_related_handle, __entry->hdr_maint_op_class, \
    + ##__VA_ARGS__)
    +
    +TRACE_EVENT(cxl_generic_event,
    +
    + TP_PROTO(const struct device *dev, enum cxl_event_log_type log,
    + struct cxl_event_record_raw *rec),
    +
    + TP_ARGS(dev, log, rec),
    +
    + TP_STRUCT__entry(
    + CXL_EVT_TP_entry
    + __array(u8, data, CXL_EVENT_RECORD_DATA_LENGTH)
    + ),
    +
    + TP_fast_assign(
    + CXL_EVT_TP_fast_assign(dev, log, rec->hdr);
    + memcpy(__entry->data, &rec->data, CXL_EVENT_RECORD_DATA_LENGTH);
    + ),
    +
    + CXL_EVT_TP_printk("%s",
    + __print_hex(__entry->data, CXL_EVENT_RECORD_DATA_LENGTH))
    +);
    +
    #endif /* _CXL_EVENTS_H */

    #define TRACE_INCLUDE_FILE trace
    diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
    index aa3af3bb73b2..5974d1082210 100644
    --- a/drivers/cxl/cxl.h
    +++ b/drivers/cxl/cxl.h
    @@ -156,6 +156,18 @@ static inline int ways_to_eiw(unsigned int ways, u8 *eiw)
    #define CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX 0x3
    #define CXLDEV_CAP_CAP_ID_MEMDEV 0x4000

    +/* CXL 3.0 8.2.8.3.1 Event Status Register */
    +#define CXLDEV_DEV_EVENT_STATUS_OFFSET 0x00
    +#define CXLDEV_EVENT_STATUS_INFO BIT(0)
    +#define CXLDEV_EVENT_STATUS_WARN BIT(1)
    +#define CXLDEV_EVENT_STATUS_FAIL BIT(2)
    +#define CXLDEV_EVENT_STATUS_FATAL BIT(3)
    +
    +#define CXLDEV_EVENT_STATUS_ALL (CXLDEV_EVENT_STATUS_INFO | \
    + CXLDEV_EVENT_STATUS_WARN | \
    + CXLDEV_EVENT_STATUS_FAIL | \
    + CXLDEV_EVENT_STATUS_FATAL)
    +
    /* CXL 2.0 8.2.8.4 Mailbox Registers */
    #define CXLDEV_MBOX_CAPS_OFFSET 0x00
    #define CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK GENMASK(4, 0)
    diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
    index ab138004f644..dd9aa3dd738e 100644
    --- a/drivers/cxl/cxlmem.h
    +++ b/drivers/cxl/cxlmem.h
    @@ -4,6 +4,7 @@
    #define __CXL_MEM_H__
    #include <uapi/linux/cxl_mem.h>
    #include <linux/cdev.h>
    +#include <linux/uuid.h>
    #include "cxl.h"

    /* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
    @@ -193,6 +194,17 @@ struct cxl_endpoint_dvsec_info {
    struct range dvsec_range[2];
    };

    +/**
    + * struct cxl_event_state - Event log driver state
    + *
    + * @event_buf: Buffer to receive event data
    + * @event_log_lock: Serialize event_buf and log use
    + */
    +struct cxl_event_state {
    + struct cxl_get_event_payload *buf;
    + struct mutex log_lock;
    +};
    +
    /**
    * struct cxl_dev_state - The driver device state
    *
    @@ -266,12 +278,16 @@ struct cxl_dev_state {

    struct xarray doe_mbs;

    + struct cxl_event_state event;
    +
    int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd);
    };

    enum cxl_opcode {
    CXL_MBOX_OP_INVALID = 0x0000,
    CXL_MBOX_OP_RAW = CXL_MBOX_OP_INVALID,
    + CXL_MBOX_OP_GET_EVENT_RECORD = 0x0100,
    + CXL_MBOX_OP_CLEAR_EVENT_RECORD = 0x0101,
    CXL_MBOX_OP_GET_FW_INFO = 0x0200,
    CXL_MBOX_OP_ACTIVATE_FW = 0x0202,
    CXL_MBOX_OP_GET_SUPPORTED_LOGS = 0x0400,
    @@ -347,6 +363,73 @@ struct cxl_mbox_identify {
    u8 qos_telemetry_caps;
    } __packed;

    +/*
    + * Common Event Record Format
    + * CXL rev 3.0 section 8.2.9.2.1; Table 8-42
    + */
    +struct cxl_event_record_hdr {
    + uuid_t id;
    + u8 length;
    + u8 flags[3];
    + __le16 handle;
    + __le16 related_handle;
    + __le64 timestamp;
    + u8 maint_op_class;
    + u8 reserved[15];
    +} __packed;
    +
    +#define CXL_EVENT_RECORD_DATA_LENGTH 0x50
    +struct cxl_event_record_raw {
    + struct cxl_event_record_hdr hdr;
    + u8 data[CXL_EVENT_RECORD_DATA_LENGTH];
    +} __packed;
    +
    +/*
    + * Get Event Records output payload
    + * CXL rev 3.0 section 8.2.9.2.2; Table 8-50
    + */
    +#define CXL_GET_EVENT_FLAG_OVERFLOW BIT(0)
    +#define CXL_GET_EVENT_FLAG_MORE_RECORDS BIT(1)
    +struct cxl_get_event_payload {
    + u8 flags;
    + u8 reserved1;
    + __le16 overflow_err_count;
    + __le64 first_overflow_timestamp;
    + __le64 last_overflow_timestamp;
    + __le16 record_count;
    + u8 reserved2[10];
    + struct cxl_event_record_raw records[];
    +} __packed;
    +
    +/*
    + * CXL rev 3.0 section 8.2.9.2.2; Table 8-49
    + */
    +enum cxl_event_log_type {
    + CXL_EVENT_TYPE_INFO = 0x00,
    + CXL_EVENT_TYPE_WARN,
    + CXL_EVENT_TYPE_FAIL,
    + CXL_EVENT_TYPE_FATAL,
    + CXL_EVENT_TYPE_MAX
    +};
    +
    +/*
    + * Clear Event Records input payload
    + * CXL rev 3.0 section 8.2.9.2.3; Table 8-51
    + */
    +#define CXL_CLEAR_EVENT_MAX_HANDLES (0xff)
    +struct cxl_mbox_clear_event_payload {
    + u8 event_log; /* enum cxl_event_log_type */
    + u8 clear_flags;
    + u8 nr_recs;
    + u8 reserved[3];
    + __le16 handle[CXL_CLEAR_EVENT_MAX_HANDLES];
    +} __packed;
    +#define CXL_CLEAR_EVENT_LIMIT_HANDLES(payload_size) \
    + (((payload_size) - \
    + (sizeof(struct cxl_mbox_clear_event_payload) - \
    + (sizeof(__le16) * CXL_CLEAR_EVENT_MAX_HANDLES))) / \
    + sizeof(__le16))
    +
    struct cxl_mbox_get_partition_info {
    __le64 active_volatile_cap;
    __le64 active_persistent_cap;
    @@ -441,6 +524,7 @@ int cxl_mem_create_range_info(struct cxl_dev_state *cxlds);
    struct cxl_dev_state *cxl_dev_state_create(struct device *dev);
    void set_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
    void clear_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
    +void cxl_mem_get_event_records(struct cxl_dev_state *cxlds, u32 status);
    #ifdef CONFIG_CXL_SUSPEND
    void cxl_mem_active_inc(void);
    void cxl_mem_active_dec(void);
    diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
    index 3a66aadb4df0..a2d8382bc593 100644
    --- a/drivers/cxl/pci.c
    +++ b/drivers/cxl/pci.c
    @@ -417,8 +417,37 @@ static void disable_aer(void *pdev)
    pci_disable_pcie_error_reporting(pdev);
    }

    +static void cxl_mem_free_event_buffer(void *buf)
    +{
    + kvfree(buf);
    +}
    +
    +/*
    + * There is a single buffer for reading event logs from the mailbox. All logs
    + * share this buffer protected by the cxlds->event_log_lock.
    + */
    +static int cxl_mem_alloc_event_buf(struct cxl_dev_state *cxlds)
    +{
    + struct cxl_get_event_payload *buf;
    +
    + dev_dbg(cxlds->dev, "Allocating event buffer size %zu\n",
    + cxlds->payload_size);
    +
    + buf = kvmalloc(cxlds->payload_size, GFP_KERNEL);
    + if (!buf)
    + return -ENOMEM;
    +
    + if (devm_add_action_or_reset(cxlds->dev, cxl_mem_free_event_buffer,
    + buf))
    + return -ENOMEM;
    +
    + cxlds->event.buf = buf;
    + return 0;
    +}
    +
    static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
    {
    + struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
    struct cxl_register_map map;
    struct cxl_memdev *cxlmd;
    struct cxl_dev_state *cxlds;
    @@ -494,6 +523,17 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
    if (IS_ERR(cxlmd))
    return PTR_ERR(cxlmd);

    + rc = cxl_mem_alloc_event_buf(cxlds);
    + if (rc)
    + return rc;
    +
    + /*
    + * When BIOS maintains CXL error reporting control, it will process
    + * event records. Only one agent can do so.
    + */
    + if (host_bridge->native_cxl_error)
    + cxl_mem_get_event_records(cxlds, CXLDEV_EVENT_STATUS_ALL);
    +
    if (cxlds->regs.ras) {
    pci_enable_pcie_error_reporting(pdev);
    rc = devm_add_action_or_reset(&pdev->dev, disable_aer, pdev);
    --
    2.37.2
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