[v2,16/27] nvdimm/ocxl: Implement the Read Error Log command
diff mbox series

Message ID 20191203034655.51561-17-alastair@au1.ibm.com
State New
Headers show
Series
  • Add support for OpenCAPI SCM devices
Related show

Commit Message

Alastair D'Silva Dec. 3, 2019, 3:46 a.m. UTC
From: Alastair D'Silva <alastair@d-silva.org>

The read error log command extracts information from the controller's
internal error log.

This patch exposes this information in 2 ways:
- During probe, if an error occurs & a log is available, print it to the
  console
- After probe, make the error log available to userspace via an IOCTL.
  Userspace is notified of pending error logs in a later patch
  ("nvdimm/ocxl: Forward events to userspace")

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
 drivers/nvdimm/ocxl/scm.c          | 270 +++++++++++++++++++++++++++++
 drivers/nvdimm/ocxl/scm_internal.h |   1 +
 include/uapi/nvdimm/ocxl-scm.h     |  46 +++++
 3 files changed, 317 insertions(+)
 create mode 100644 include/uapi/nvdimm/ocxl-scm.h

Comments

Alastair D'Silva Dec. 5, 2019, 3:42 a.m. UTC | #1
On Tue, 2019-12-03 at 14:46 +1100, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> The read error log command extracts information from the controller's
> internal error log.
> 
> This patch exposes this information in 2 ways:
> - During probe, if an error occurs & a log is available, print it to
> the
>   console
> - After probe, make the error log available to userspace via an
> IOCTL.
>   Userspace is notified of pending error logs in a later patch
>   ("nvdimm/ocxl: Forward events to userspace")
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>  drivers/nvdimm/ocxl/scm.c          | 270
> +++++++++++++++++++++++++++++
>  drivers/nvdimm/ocxl/scm_internal.h |   1 +
>  include/uapi/nvdimm/ocxl-scm.h     |  46 +++++
>  3 files changed, 317 insertions(+)
>  create mode 100644 include/uapi/nvdimm/ocxl-scm.h
> 
> diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
> index c313a473a28e..0bbe1a14291e 100644
> --- a/drivers/nvdimm/ocxl/scm.c
> +++ b/drivers/nvdimm/ocxl/scm.c
> @@ -495,10 +495,220 @@ static int scm_file_release(struct inode
> *inode, struct file *file)
>  	return 0;
>  }
>  
> +/**
> + * scm_error_log_header_parse() - Parse the first 64 bits of the
> error log command response
> + * @scm_data: the SCM metadata
> + * @length: out, returns the number of bytes in the response
> (excluding the 64 bit header)
> + */
> +static int scm_error_log_header_parse(struct scm_data *scm_data, u16
> *length)
> +{
> +	int rc;
> +	u64 val;
> +
> +	u16 data_identifier;
> +	u32 data_length;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset,
> +				     OCXL_LITTLE_ENDIAN, &val);
> +	if (rc)
> +		return rc;
> +
> +	data_identifier = val >> 48;
> +	data_length = val & 0xFFFF;
> +
> +	if (data_identifier != 0x454C) {
> +		dev_err(&scm_data->dev,
> +			"Bad data identifier for error log data,
> expected 'EL', got '%2s' (%#x), data_length=%u\n",
> +			(char *)&data_identifier,
> +			(unsigned int)data_identifier, data_length);
> +		return -EINVAL;
> +	}
> +
> +	*length = data_length;
> +	return 0;
> +}
> +
> +static int scm_error_log_offset_0x08(struct scm_data *scm_data,
> +				     u32 *log_identifier, u32
> *program_ref_code)
> +{
> +	int rc;
> +	u64 val;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset + 0x08,
> +				     OCXL_LITTLE_ENDIAN, &val);
> +	if (rc)
> +		return rc;
> +
> +	*log_identifier = val >> 32;
> +	*program_ref_code = val & 0xFFFFFFFF;
> +
> +	return 0;
> +}
> +
> +static int scm_read_error_log(struct scm_data *scm_data,
> +			      struct scm_ioctl_error_log *log, bool
> buf_is_user)
> +{
> +	u64 val;
> +	u16 user_buf_length;
> +	u16 buf_length;
> +	u16 i;
> +	int rc;
> +
> +	if (log->buf_size % 8)
> +		return -EINVAL;
> +
> +	rc = scm_chi(scm_data, &val);
> +	if (rc)
> +		goto out;
> +
> +	if (!(val & GLOBAL_MMIO_CHI_ELA))
> +		return -EAGAIN;
> +
> +	user_buf_length = log->buf_size;
> +
> +	mutex_lock(&scm_data->admin_command.lock);
> +
> +	rc = scm_admin_command_request(scm_data, ADMIN_COMMAND_ERRLOG);
> +	if (rc)
> +		goto out;
> +
> +	rc = scm_admin_command_execute(scm_data);
> +	if (rc)
> +		goto out;
> +
> +	rc = scm_admin_command_complete_timeout(scm_data,
> ADMIN_COMMAND_ERRLOG);
> +	if (rc < 0) {
> +		dev_warn(&scm_data->dev, "Read error log timed out\n");
> +		goto out;
> +	}
> +
> +	rc = scm_admin_response(scm_data);
> +	if (rc < 0)
> +		goto out;
> +	if (rc != STATUS_SUCCESS) {
> +		scm_warn_status(scm_data, "Unexpected status from
> retrieve error log", rc);
> +		goto out;
> +	}
> +
> +
> +	rc = scm_error_log_header_parse(scm_data, &log->buf_size);
> +	if (rc)
> +		goto out;
> +	// log->buf_size now contains the scm buffer size, not the user
> size
> +
> +	rc = scm_error_log_offset_0x08(scm_data, &log->log_identifier,
> +				       &log->program_reference_code);
> +	if (rc)
> +		goto out;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset + 0x10,
> +				     OCXL_LITTLE_ENDIAN, &val);
> +	if (rc)
> +		goto out;
> +
> +	log->error_log_type = val >> 56;
> +	log->action_flags = (log->error_log_type ==
> SCM_ERROR_LOG_TYPE_GENERAL) ?
> +			    (val >> 32) & 0xFFFFFF : 0;
> +	log->power_on_seconds = val & 0xFFFFFFFF;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset + 0x18,
> +				     OCXL_LITTLE_ENDIAN, &log-
> >timestamp);
> +	if (rc)
> +		goto out;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset + 0x20,
> +				     OCXL_HOST_ENDIAN, &log->wwid[0]);
> +	if (rc)
> +		goto out;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset + 0x28,
> +				     OCXL_HOST_ENDIAN, &log->wwid[1]);
> +	if (rc)
> +		goto out;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +				     scm_data-
> >admin_command.data_offset + 0x30,
> +				     OCXL_HOST_ENDIAN, (u64 *)log-
> >fw_revision);
> +	if (rc)
> +		goto out;
> +	log->fw_revision[8] = '\0';
> +
> +	buf_length = (user_buf_length < log->buf_size) ?
> +		     user_buf_length : log->buf_size;
> +	for (i = 0; i < buf_length + 0x48; i += 8) {
> +		u64 val;
> +
> +		rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
> +					     scm_data-
> >admin_command.data_offset + i,
> +					     OCXL_HOST_ENDIAN, &val);
> +		if (rc)
> +			goto out;
> +
> +		if (buf_is_user) {
> +			if (copy_to_user(&log->buf[i], &val,
> sizeof(u64))) {
> +				rc = -EFAULT;
> +				goto out;
> +			}
> +		} else
> +			log->buf[i] = val;
> +	}
> +
> +	rc = scm_admin_response_handled(scm_data);
> +	if (rc)
> +		goto out;
> +
> +out:
> +	mutex_unlock(&scm_data->admin_command.lock);
> +	return rc;
> +
> +}
> +
> +static int scm_ioctl_error_log(struct scm_data *scm_data,
> +			       struct scm_ioctl_error_log __user *uarg)
> +{
> +	struct scm_ioctl_error_log args;
> +	int rc;
> +
> +	if (copy_from_user(&args, uarg, sizeof(args)))
> +		return -EFAULT;
> +
> +	rc = scm_read_error_log(scm_data, &args, true);
> +	if (rc)
> +		return rc;
> +
> +	if (copy_to_user(uarg, &args, sizeof(args)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
> +static long scm_file_ioctl(struct file *file, unsigned int cmd,
> +			   unsigned long args)
> +{
> +	struct scm_data *scm_data = file->private_data;
> +	int rc = -EINVAL;
> +
> +	switch (cmd) {
> +	case SCM_IOCTL_ERROR_LOG:
> +		rc = scm_ioctl_error_log(scm_data,
> +					 (struct scm_ioctl_error_log
> __user *)args);
> +		break;
> +	}
> +	return rc;
> +}
> +
>  static const struct file_operations scm_fops = {
>  	.owner		= THIS_MODULE,
>  	.open		= scm_file_open,
>  	.release	= scm_file_release,
> +	.unlocked_ioctl = scm_file_ioctl,
> +	.compat_ioctl   = scm_file_ioctl,
>  };
>  
>  /**
> @@ -575,6 +785,60 @@ static int read_device_metadata(struct scm_data
> *scm_data)
>  	return 0;
>  }
>  
> +static const char *scm_decode_error_log_type(u8 error_log_type)
> +{
> +	switch (error_log_type) {
> +	case 0x00:
> +		return "general";
> +	case 0x01:
> +		return "predictive failure";
> +	case 0x02:
> +		return "thermal warning";
> +	case 0x03:
> +		return "data loss";
> +	case 0x04:
> +		return "health & performance";
> +	default:
> +		return "unknown";
> +	}
> +}
> +
> +static void scm_dump_error_log(struct scm_data *scm_data)
> +{
> +	struct scm_ioctl_error_log log;
> +	u32 buf_size;
> +	u8 *buf;
> +	int rc;
> +
> +	if (scm_data->admin_command.data_size == 0)
> +		return;
> +
> +	buf_size = scm_data->admin_command.data_size - 0x48;
> +	buf = kzalloc(buf_size, GFP_KERNEL);
> +	if (!buf)
> +		return;
> +
> +	log.buf = buf;
> +	log.buf_size = buf_size;
> +
> +	rc = scm_read_error_log(scm_data, &log, false);
> +	if (rc < 0)
> +		goto out;
> +
> +	dev_warn(&scm_data->dev,
> +		 "SCM Error log: WWID=0x%016llx%016llx LID=0x%x PRC=%x
> type=0x%x %s, Uptime=%u seconds timestamp=0x%llx\n",
> +		 log.wwid[0], log.wwid[1],
> +		 log.log_identifier, log.program_reference_code,
> +		 log.error_log_type,
> +		 scm_decode_error_log_type(log.error_log_type),
> +		 log.power_on_seconds, log.timestamp);
> +	print_hex_dump(KERN_WARNING, "buf", DUMP_PREFIX_OFFSET, 16, 1,
> buf,
> +		       log.buf_size, false);
> +
> +out:
> +	kfree(buf);
> +}
> +
>  /**
>   * scm_probe_function_0 - Set up function 0 for an OpenCAPI Storage
> Class Memory device
>   * This is important as it enables templates higher than 0 across
> all other functions,
> @@ -617,6 +881,7 @@ static int scm_probe(struct pci_dev *pdev, const
> struct pci_device_id *ent)
>  	struct scm_data *scm_data = NULL;
>  	int elapsed;
>  	u16 timeout;
> +	u64 chi;
>  
>  	if (PCI_FUNC(pdev->devfn) == 0)
>  		return scm_probe_function_0(pdev);
> @@ -707,6 +972,11 @@ static int scm_probe(struct pci_dev *pdev, const
> struct pci_device_id *ent)
>  	return 0;
>  
>  err:
> +	if (scm_data &&
> +		    (scm_chi(scm_data, &chi) == 0) &&
> +		    (chi & GLOBAL_MMIO_CHI_ELA))
> +		scm_dump_error_log(scm_data);
> +
>  	/*
>  	 * Further cleanup is done in the release handler via
> free_scm()
>  	 * This allows us to keep the character device live to handle
> IOCTLs to
> diff --git a/drivers/nvdimm/ocxl/scm_internal.h
> b/drivers/nvdimm/ocxl/scm_internal.h
> index 57491dbee1a4..9bf8fcf30ea6 100644
> --- a/drivers/nvdimm/ocxl/scm_internal.h
> +++ b/drivers/nvdimm/ocxl/scm_internal.h
> @@ -5,6 +5,7 @@
>  #include <linux/cdev.h>
>  #include <misc/ocxl.h>
>  #include <linux/libnvdimm.h>
> +#include <uapi/linux/ocxl-scm.h>

This should be uapi/nvdimm/ocxl-scm.h

>  #include <linux/mm.h>
>  
>  #define SCM_DEFAULT_TIMEOUT 100
> diff --git a/include/uapi/nvdimm/ocxl-scm.h
> b/include/uapi/nvdimm/ocxl-scm.h
> new file mode 100644
> index 000000000000..b34dd1ba06ff
> --- /dev/null
> +++ b/include/uapi/nvdimm/ocxl-scm.h
> @@ -0,0 +1,46 @@
> +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> +/* Copyright 2017 IBM Corp. */
> +#ifndef _UAPI_OCXL_SCM_H
> +#define _UAPI_OCXL_SCM_H
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +#define SCM_ERROR_LOG_ACTION_RESET	(1 << (32-32))
> +#define SCM_ERROR_LOG_ACTION_CHKFW	(1 << (53-32))
> +#define SCM_ERROR_LOG_ACTION_REPLACE	(1 << (54-32))
> +#define SCM_ERROR_LOG_ACTION_DUMP	(1 << (55-32))
> +
> +#define SCM_ERROR_LOG_TYPE_GENERAL		(0x00)
> +#define SCM_ERROR_LOG_TYPE_PREDICTIVE_FAILURE	(0x01)
> +#define SCM_ERROR_LOG_TYPE_THERMAL_WARNING	(0x02)
> +#define SCM_ERROR_LOG_TYPE_DATA_LOSS		(0x03)
> +#define SCM_ERROR_LOG_TYPE_HEALTH_PERFORMANCE	(0x04)
> +
> +struct scm_ioctl_error_log {
> +	__u32 log_identifier; // out
> +	__u32 program_reference_code; // out
> +	__u32 action_flags; //out, recommended course of action
> +	__u32 power_on_seconds; // out, Number of seconds the
> controller has been on when the error occurred
> +	__u64 timestamp; // out, relative time since the current IPL
> +	__u64 wwid[2]; // out, the NAA formatted WWID associated with
> the controller
> +	char  fw_revision[8+1]; // out, firmware revision as null
> terminated text
> +	__u16 buf_size; /* in/out, buffer size provided/required.
> +			 * If required is greater than provided, the
> buffer
> +			 * will be truncated to the amount provided. If
> its
> +			 * less, then only the required bytes will be
> populated.
> +			 * If it is 0, then there are no more error log
> entries.
> +			 */
> +	__u8  error_log_type;
> +	__u8  reserved1;
> +	__u32 reserved2;
> +	__u64 reserved3[2];
> +	__u8 *buf; // pointer to output buffer
> +};
> +
> +/* ioctl numbers */
> +#define SCM_MAGIC 0x5C
> +/* SCM devices */
> +#define SCM_IOCTL_ERROR_LOG	_IOWR(SCM_MAGIC, 0x01, struct
> scm_ioctl_error_log)
> +
> +#endif /* _UAPI_OCXL_SCM_H */
kbuild test robot Dec. 5, 2019, 7:34 p.m. UTC | #2
Hi Alastair,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v5.4-rc8]
[also build test ERROR on char-misc/char-misc-testing]
[cannot apply to linux-nvdimm/libnvdimm-for-next linus/master next-20191205]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Alastair-D-Silva/Add-support-for-OpenCAPI-SCM-devices/20191203-120511
base:    af42d3466bdc8f39806b26f593604fdc54140bcb
config: x86_64-randconfig-b001-20191203 (attached as .config)
compiler: gcc-7 (Debian 7.5.0-1) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from <command-line>:32:0:
>> ./usr/include/nvdimm/ocxl-scm.h:21:24: error: C++ style comments are not allowed in ISO C90
     __u32 log_identifier; // out
                           ^
>> ./usr/include/nvdimm/ocxl-scm.h:21:24: error: (this will be reported only once per input file)

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation

Patch
diff mbox series

diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
index c313a473a28e..0bbe1a14291e 100644
--- a/drivers/nvdimm/ocxl/scm.c
+++ b/drivers/nvdimm/ocxl/scm.c
@@ -495,10 +495,220 @@  static int scm_file_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
+/**
+ * scm_error_log_header_parse() - Parse the first 64 bits of the error log command response
+ * @scm_data: the SCM metadata
+ * @length: out, returns the number of bytes in the response (excluding the 64 bit header)
+ */
+static int scm_error_log_header_parse(struct scm_data *scm_data, u16 *length)
+{
+	int rc;
+	u64 val;
+
+	u16 data_identifier;
+	u32 data_length;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset,
+				     OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		return rc;
+
+	data_identifier = val >> 48;
+	data_length = val & 0xFFFF;
+
+	if (data_identifier != 0x454C) {
+		dev_err(&scm_data->dev,
+			"Bad data identifier for error log data, expected 'EL', got '%2s' (%#x), data_length=%u\n",
+			(char *)&data_identifier,
+			(unsigned int)data_identifier, data_length);
+		return -EINVAL;
+	}
+
+	*length = data_length;
+	return 0;
+}
+
+static int scm_error_log_offset_0x08(struct scm_data *scm_data,
+				     u32 *log_identifier, u32 *program_ref_code)
+{
+	int rc;
+	u64 val;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset + 0x08,
+				     OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		return rc;
+
+	*log_identifier = val >> 32;
+	*program_ref_code = val & 0xFFFFFFFF;
+
+	return 0;
+}
+
+static int scm_read_error_log(struct scm_data *scm_data,
+			      struct scm_ioctl_error_log *log, bool buf_is_user)
+{
+	u64 val;
+	u16 user_buf_length;
+	u16 buf_length;
+	u16 i;
+	int rc;
+
+	if (log->buf_size % 8)
+		return -EINVAL;
+
+	rc = scm_chi(scm_data, &val);
+	if (rc)
+		goto out;
+
+	if (!(val & GLOBAL_MMIO_CHI_ELA))
+		return -EAGAIN;
+
+	user_buf_length = log->buf_size;
+
+	mutex_lock(&scm_data->admin_command.lock);
+
+	rc = scm_admin_command_request(scm_data, ADMIN_COMMAND_ERRLOG);
+	if (rc)
+		goto out;
+
+	rc = scm_admin_command_execute(scm_data);
+	if (rc)
+		goto out;
+
+	rc = scm_admin_command_complete_timeout(scm_data, ADMIN_COMMAND_ERRLOG);
+	if (rc < 0) {
+		dev_warn(&scm_data->dev, "Read error log timed out\n");
+		goto out;
+	}
+
+	rc = scm_admin_response(scm_data);
+	if (rc < 0)
+		goto out;
+	if (rc != STATUS_SUCCESS) {
+		scm_warn_status(scm_data, "Unexpected status from retrieve error log", rc);
+		goto out;
+	}
+
+
+	rc = scm_error_log_header_parse(scm_data, &log->buf_size);
+	if (rc)
+		goto out;
+	// log->buf_size now contains the scm buffer size, not the user size
+
+	rc = scm_error_log_offset_0x08(scm_data, &log->log_identifier,
+				       &log->program_reference_code);
+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset + 0x10,
+				     OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		goto out;
+
+	log->error_log_type = val >> 56;
+	log->action_flags = (log->error_log_type == SCM_ERROR_LOG_TYPE_GENERAL) ?
+			    (val >> 32) & 0xFFFFFF : 0;
+	log->power_on_seconds = val & 0xFFFFFFFF;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset + 0x18,
+				     OCXL_LITTLE_ENDIAN, &log->timestamp);
+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset + 0x20,
+				     OCXL_HOST_ENDIAN, &log->wwid[0]);
+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset + 0x28,
+				     OCXL_HOST_ENDIAN, &log->wwid[1]);
+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+				     scm_data->admin_command.data_offset + 0x30,
+				     OCXL_HOST_ENDIAN, (u64 *)log->fw_revision);
+	if (rc)
+		goto out;
+	log->fw_revision[8] = '\0';
+
+	buf_length = (user_buf_length < log->buf_size) ?
+		     user_buf_length : log->buf_size;
+	for (i = 0; i < buf_length + 0x48; i += 8) {
+		u64 val;
+
+		rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+					     scm_data->admin_command.data_offset + i,
+					     OCXL_HOST_ENDIAN, &val);
+		if (rc)
+			goto out;
+
+		if (buf_is_user) {
+			if (copy_to_user(&log->buf[i], &val, sizeof(u64))) {
+				rc = -EFAULT;
+				goto out;
+			}
+		} else
+			log->buf[i] = val;
+	}
+
+	rc = scm_admin_response_handled(scm_data);
+	if (rc)
+		goto out;
+
+out:
+	mutex_unlock(&scm_data->admin_command.lock);
+	return rc;
+
+}
+
+static int scm_ioctl_error_log(struct scm_data *scm_data,
+			       struct scm_ioctl_error_log __user *uarg)
+{
+	struct scm_ioctl_error_log args;
+	int rc;
+
+	if (copy_from_user(&args, uarg, sizeof(args)))
+		return -EFAULT;
+
+	rc = scm_read_error_log(scm_data, &args, true);
+	if (rc)
+		return rc;
+
+	if (copy_to_user(uarg, &args, sizeof(args)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long scm_file_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long args)
+{
+	struct scm_data *scm_data = file->private_data;
+	int rc = -EINVAL;
+
+	switch (cmd) {
+	case SCM_IOCTL_ERROR_LOG:
+		rc = scm_ioctl_error_log(scm_data,
+					 (struct scm_ioctl_error_log __user *)args);
+		break;
+	}
+	return rc;
+}
+
 static const struct file_operations scm_fops = {
 	.owner		= THIS_MODULE,
 	.open		= scm_file_open,
 	.release	= scm_file_release,
+	.unlocked_ioctl = scm_file_ioctl,
+	.compat_ioctl   = scm_file_ioctl,
 };
 
 /**
@@ -575,6 +785,60 @@  static int read_device_metadata(struct scm_data *scm_data)
 	return 0;
 }
 
+static const char *scm_decode_error_log_type(u8 error_log_type)
+{
+	switch (error_log_type) {
+	case 0x00:
+		return "general";
+	case 0x01:
+		return "predictive failure";
+	case 0x02:
+		return "thermal warning";
+	case 0x03:
+		return "data loss";
+	case 0x04:
+		return "health & performance";
+	default:
+		return "unknown";
+	}
+}
+
+static void scm_dump_error_log(struct scm_data *scm_data)
+{
+	struct scm_ioctl_error_log log;
+	u32 buf_size;
+	u8 *buf;
+	int rc;
+
+	if (scm_data->admin_command.data_size == 0)
+		return;
+
+	buf_size = scm_data->admin_command.data_size - 0x48;
+	buf = kzalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	log.buf = buf;
+	log.buf_size = buf_size;
+
+	rc = scm_read_error_log(scm_data, &log, false);
+	if (rc < 0)
+		goto out;
+
+	dev_warn(&scm_data->dev,
+		 "SCM Error log: WWID=0x%016llx%016llx LID=0x%x PRC=%x type=0x%x %s, Uptime=%u seconds timestamp=0x%llx\n",
+		 log.wwid[0], log.wwid[1],
+		 log.log_identifier, log.program_reference_code,
+		 log.error_log_type,
+		 scm_decode_error_log_type(log.error_log_type),
+		 log.power_on_seconds, log.timestamp);
+	print_hex_dump(KERN_WARNING, "buf", DUMP_PREFIX_OFFSET, 16, 1, buf,
+		       log.buf_size, false);
+
+out:
+	kfree(buf);
+}
+
 /**
  * scm_probe_function_0 - Set up function 0 for an OpenCAPI Storage Class Memory device
  * This is important as it enables templates higher than 0 across all other functions,
@@ -617,6 +881,7 @@  static int scm_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct scm_data *scm_data = NULL;
 	int elapsed;
 	u16 timeout;
+	u64 chi;
 
 	if (PCI_FUNC(pdev->devfn) == 0)
 		return scm_probe_function_0(pdev);
@@ -707,6 +972,11 @@  static int scm_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	return 0;
 
 err:
+	if (scm_data &&
+		    (scm_chi(scm_data, &chi) == 0) &&
+		    (chi & GLOBAL_MMIO_CHI_ELA))
+		scm_dump_error_log(scm_data);
+
 	/*
 	 * Further cleanup is done in the release handler via free_scm()
 	 * This allows us to keep the character device live to handle IOCTLs to
diff --git a/drivers/nvdimm/ocxl/scm_internal.h b/drivers/nvdimm/ocxl/scm_internal.h
index 57491dbee1a4..9bf8fcf30ea6 100644
--- a/drivers/nvdimm/ocxl/scm_internal.h
+++ b/drivers/nvdimm/ocxl/scm_internal.h
@@ -5,6 +5,7 @@ 
 #include <linux/cdev.h>
 #include <misc/ocxl.h>
 #include <linux/libnvdimm.h>
+#include <uapi/linux/ocxl-scm.h>
 #include <linux/mm.h>
 
 #define SCM_DEFAULT_TIMEOUT 100
diff --git a/include/uapi/nvdimm/ocxl-scm.h b/include/uapi/nvdimm/ocxl-scm.h
new file mode 100644
index 000000000000..b34dd1ba06ff
--- /dev/null
+++ b/include/uapi/nvdimm/ocxl-scm.h
@@ -0,0 +1,46 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/* Copyright 2017 IBM Corp. */
+#ifndef _UAPI_OCXL_SCM_H
+#define _UAPI_OCXL_SCM_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define SCM_ERROR_LOG_ACTION_RESET	(1 << (32-32))
+#define SCM_ERROR_LOG_ACTION_CHKFW	(1 << (53-32))
+#define SCM_ERROR_LOG_ACTION_REPLACE	(1 << (54-32))
+#define SCM_ERROR_LOG_ACTION_DUMP	(1 << (55-32))
+
+#define SCM_ERROR_LOG_TYPE_GENERAL		(0x00)
+#define SCM_ERROR_LOG_TYPE_PREDICTIVE_FAILURE	(0x01)
+#define SCM_ERROR_LOG_TYPE_THERMAL_WARNING	(0x02)
+#define SCM_ERROR_LOG_TYPE_DATA_LOSS		(0x03)
+#define SCM_ERROR_LOG_TYPE_HEALTH_PERFORMANCE	(0x04)
+
+struct scm_ioctl_error_log {
+	__u32 log_identifier; // out
+	__u32 program_reference_code; // out
+	__u32 action_flags; //out, recommended course of action
+	__u32 power_on_seconds; // out, Number of seconds the controller has been on when the error occurred
+	__u64 timestamp; // out, relative time since the current IPL
+	__u64 wwid[2]; // out, the NAA formatted WWID associated with the controller
+	char  fw_revision[8+1]; // out, firmware revision as null terminated text
+	__u16 buf_size; /* in/out, buffer size provided/required.
+			 * If required is greater than provided, the buffer
+			 * will be truncated to the amount provided. If its
+			 * less, then only the required bytes will be populated.
+			 * If it is 0, then there are no more error log entries.
+			 */
+	__u8  error_log_type;
+	__u8  reserved1;
+	__u32 reserved2;
+	__u64 reserved3[2];
+	__u8 *buf; // pointer to output buffer
+};
+
+/* ioctl numbers */
+#define SCM_MAGIC 0x5C
+/* SCM devices */
+#define SCM_IOCTL_ERROR_LOG	_IOWR(SCM_MAGIC, 0x01, struct scm_ioctl_error_log)
+
+#endif /* _UAPI_OCXL_SCM_H */