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Message-ID: <1753de1d-e8a0-ffa3-9e2a-350df926f5cd@redhat.com>
Date:   Thu, 10 Sep 2020 14:51:52 -0700
From:   Tom Rix <trix@...hat.com>
To:     Russ Weight <russell.h.weight@...el.com>, mdf@...nel.org,
        lee.jones@...aro.org, linux-fpga@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     lgoncalv@...hat.com, yilun.xu@...el.com, hao.wu@...el.com,
        matthew.gerlach@...el.com
Subject: Re: [PATCH v1 01/12] fpga: fpga security manager class driver


On 9/10/20 1:22 PM, Russ Weight wrote:
>     
>
> On 9/5/20 12:09 PM, Tom Rix wrote:
>
>    
>
>>       
>> On 9/4/20 4:52 PM, Russ Weight wrote:
>>       
>>>         
>>> Create the Intel Security Manager class driver. The security
>>> manager provides interfaces to manage secure updates for the
>>> FPGA and BMC images that are stored in FLASH. The driver can
>>> also be used to update root entry hashes and to cancel code
>>> signing keys.
>>>
>>> This patch creates the class driver and provides sysfs
>>> interfaces for displaying root entry hashes, canceled code
>>> signing keys and flash counts.
>>>
>>> Signed-off-by: Russ Weight <russell.h.weight@...el.com>
>>> Signed-off-by: Xu Yilun <yilun.xu@...el.com>
>>> ---
>>>  .../ABI/testing/sysfs-class-ifpga-sec-mgr     |  75 ++++
>>>  MAINTAINERS                                   |   8 +
>>>  drivers/fpga/Kconfig                          |   9 +
>>>  drivers/fpga/Makefile                         |   3 +
>>>  drivers/fpga/ifpga-sec-mgr.c                  | 339 ++++++++++++++++++
>>>  include/linux/fpga/ifpga-sec-mgr.h            | 145 ++++++++
>>>  6 files changed, 579 insertions(+)
>>>  create mode 100644 Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
>>>  create mode 100644 drivers/fpga/ifpga-sec-mgr.c
>>>  create mode 100644 include/linux/fpga/ifpga-sec-mgr.h
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
>>> new file mode 100644
>>> index 000000000000..86f8992559bf
>>> --- /dev/null
>>> +++ b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
>>> @@ -0,0 +1,75 @@
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/name
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Name of low level fpga security manager driver.
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/sr_root_entry_hash
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns the root entry hash for the static
>>> +		region if one is programmed, else it returns the
>>> +		string: "hash not programmed".  This file is only
>>> +		visible if the underlying device supports it.
>>> +		Format: "0x%x".
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/pr_root_entry_hash
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns the root entry hash for the partial
>>> +		reconfiguration region if one is programmed, else it
>>> +		returns the string: "hash not programmed".  This file
>>> +		is only visible if the underlying device supports it.
>>> +		Format: "0x%x".
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/bmc_root_entry_hash
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns the root entry hash for the BMC image
>>> +		if one is programmed, else it returns the string:
>>> +		"hash not programmed".  This file is only visible if the
>>> +		underlying device supports it.
>>> +		Format: "0x%x".
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/sr_canceled_csks
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns a list of indices for canceled code
>>> +		signing keys for the static region. The standard bitmap
>>> +		list format is used (e.g. "1,2-6,9").
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/pr_canceled_csks
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns a list of indices for canceled code
>>> +		signing keys for the partial reconfiguration region. The
>>> +		standard bitmap list format is used (e.g. "1,2-6,9").
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/bmc_canceled_csks
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns a list of indices for canceled code
>>> +		signing keys for the BMC.  The standard bitmap list format
>>> +		is used (e.g. "1,2-6,9").
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/user_flash_count
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns number of times the user image for the
>>> +		static region has been flashed.
>>> +		Format: "%d".
>>>       
>>       
>> could this be %u ?
>>     
> Yes - I'll make the change for both of the flash update counts.
>
>>       
>>>         
>>> +
>>> +What: 		/sys/class/ifpga_sec_mgr/ifpga_secX/security/bmc_flash_count
>>> +Date:		Sep 2020
>>> +KernelVersion:  5.10
>>> +Contact:	Russ Weight <russell.h.weight@...el.com>
>>> +Description:	Read only. Returns number of times the BMC image has been
>>> +		flashed.
>>> +		Format: "%d".
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index deaafb617361..4a2ebe6b120d 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -6830,6 +6830,14 @@ F:	Documentation/fpga/
>>>  F:	drivers/fpga/
>>>  F:	include/linux/fpga/
>>>  
>>> +INTEL FPGA SECURITY MANAGER DRIVERS
>>> +M:	Russ Weight <russell.h.weight@...el.com>
>>> +L:	linux-fpga@...r.kernel.org
>>> +S:	Maintained
>>> +F:	Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
>>> +F:	drivers/fpga/ifpga-sec-mgr.c
>>> +F:	include/linux/fpga/ifpga-sec-mgr.h
>>> +
>>>  FPU EMULATOR
>>>  M:	Bill Metzenthen <billm@...bpc.org.au>
>>>  S:	Maintained
>>> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
>>> index 88f64fbf55e3..97c0a6cc2ba7 100644
>>> --- a/drivers/fpga/Kconfig
>>> +++ b/drivers/fpga/Kconfig
>>> @@ -235,4 +235,13 @@ config FPGA_MGR_ZYNQMP_FPGA
>>>  	  to configure the programmable logic(PL) through PS
>>>  	  on ZynqMP SoC.
>>>  
>>> +config IFPGA_SEC_MGR
>>> +	tristate "Intel Security Manager for FPGA"
>>> +        help
>>> +	  The Intel Security Manager class driver presents a common
>>> +	  user API for managing secure updates for Intel FPGA
>>> +	  devices, including flash images for the FPGA static
>>> +	  region and for the BMC. Select this option to enable
>>> +	  updates for secure FPGA devices.
>>> +
>>>  endif # FPGA
>>> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
>>> index c69bfc931519..ec9fbacdedd8 100644
>>> --- a/drivers/fpga/Makefile
>>> +++ b/drivers/fpga/Makefile
>>> @@ -21,6 +21,9 @@ obj-$(CONFIG_FPGA_MGR_ZYNQMP_FPGA)	+= zynqmp-fpga.o
>>>  obj-$(CONFIG_ALTERA_PR_IP_CORE)         += altera-pr-ip-core.o
>>>  obj-$(CONFIG_ALTERA_PR_IP_CORE_PLAT)    += altera-pr-ip-core-plat.o
>>>  
>>> +# Intel FPGA Security Manager Framework
>>> +obj-$(CONFIG_IFPGA_SEC_MGR)		+= ifpga-sec-mgr.o
>>> +
>>>  # FPGA Bridge Drivers
>>>  obj-$(CONFIG_FPGA_BRIDGE)		+= fpga-bridge.o
>>>  obj-$(CONFIG_SOCFPGA_FPGA_BRIDGE)	+= altera-hps2fpga.o altera-fpga2sdram.o
>>> diff --git a/drivers/fpga/ifpga-sec-mgr.c b/drivers/fpga/ifpga-sec-mgr.c
>>> new file mode 100644
>>> index 000000000000..97bf80277ed2
>>> --- /dev/null
>>> +++ b/drivers/fpga/ifpga-sec-mgr.c
>>> @@ -0,0 +1,339 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Intel Security Manager for FPGA
>>> + *
>>> + * Copyright (C) 2019-2020 Intel Corporation, Inc.
>>> + */
>>> +
>>> +#include <linux/fpga/ifpga-sec-mgr.h>
>>> +#include <linux/idr.h>
>>> +#include <linux/module.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/vmalloc.h>
>>> +
>>> +static DEFINE_IDA(ifpga_sec_mgr_ida);
>>> +static struct class *ifpga_sec_mgr_class;
>>> +
>>> +static ssize_t show_canceled_csk(struct ifpga_sec_mgr *imgr,
>>> +				 sysfs_csk_hndlr_t get_csk,
>>> +				 sysfs_csk_nbits_t get_csk_nbits,
>>>       
>>       
>> Param 2&3 can be accessed by imgr->iops so the signature
>>
>> of this and similar functions should be reduced.
>>     
> There are three different types of CSK vectors (sr, pr, and bmc).
> For each type, there are two function pointers. When calling
> show_canceled_csk, it is necessary to identify the type of CSK.
> While it is true that all three pairs of pointers are in imgr->iops,
> I think the easiest way to identify the CSK type is by passing in
> the appropriate pair of pointers.
ok.
>>       
>>       
>>>         
>>> +				 char *buf)
>>> +{
>>> +	unsigned long *csk_map = NULL;
>>> +	unsigned int nbits;
>>> +	int cnt, ret;
>>> +
>>> +	ret = get_csk_nbits(imgr);
>>>       
>>       
>> Any access to a function pointer must check if the
>>
>> the pointer is valid.
>>     
> The pointers are all validated when a device driver registers with the class
> driver. The corresponding CSK sysfs file will only be visible if the pointers
> have been validated. Is that sufficient, or should I add a redundant check
> here? I don't mind doing it if you think it is needed.
ok, fine as-is.
>
>>       
>>       
>>>         
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	nbits = (unsigned int)ret;
>>> +	csk_map = vmalloc(sizeof(unsigned long) * BITS_TO_LONGS(nbits));
>>> +	if (!csk_map)
>>> +		return -ENOMEM;
>>> +
>>> +	ret = get_csk(imgr, csk_map, nbits);
>>>       
>>       
>> The type of returned by get_csk_nbits and its use should
>>
>> be consistent. likely this is 'int'
> The CSK data is returned using memory provided by the csk_map pointer parameter. The
> return value is an integer value and provides error/success status. Do you think
> something should be changed here?

Later i comment on how the error code duplicate standard error codes.

It would be good the standard codes could be used, part of that

is returning int.

>
>>       
>>>         
>>> +	if (ret)
>>> +		goto vfree_exit;
>>> +
>>> +	cnt = bitmap_print_to_pagebuf(1, buf, csk_map, nbits);
>>>       
>>       
>> simplify to
>>
>> ret = ..
> Sure - I will do that.
>
>>
>>       
>>>         
>>> +
>>> +vfree_exit:
>>> +	vfree(csk_map);
>>> +	return ret ? : cnt;
>>> +}
>>> +
>>> +static ssize_t show_root_entry_hash(struct ifpga_sec_mgr *imgr,
>>> +				    sysfs_reh_hndlr_t get_reh,
>>> +				    sysfs_reh_size_t get_reh_size,
>>> +				    char *buf)
>>> +{
>>> +	unsigned int size, i;
>>> +	int ret, cnt = 0;
>>> +	u8 *hash;
>>> +
>>> +	ret = get_reh_size(imgr);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +	else if (!ret)
>>> +		return sprintf(buf, "hash not programmed\n");
>>> +
>>> +	size = (unsigned int)ret;
>>>       
>>       
>> does size and i need to unsigned?
> In the context of their usage here, they should never be negative. Sizes are
> typically unsigned, right? Would there be a reason to prefer int over unsigned?

My issue is specifically the typecast. It would be good

if the typecast could be removed.

>
>>       
>>>         
>>> +	hash = vmalloc(size);
>>> +	if (!hash)
>>> +		return -ENOMEM;
>>> +
>>> +	ret = get_reh(imgr, hash, size);
>>> +	if (ret)
>>> +		goto vfree_exit;
>>>       
>>       
>> ret is 0 here
>>
>> so simplify replacing cnt with ret.
> Is the goal to have less variables? It seems like a trade-off with readability...
>
> I can make this change.

The next comment/change will makes this comment superfluous.

ignore it. 

>
>>       
>>>         
>>> +
>>> +	cnt += sprintf(buf, "0x");
>>>       
>>       
>> or change += to =, this is the first time sprintf is done.
> Sure - I 'll just do the assignment instead if initializing to zero.
>
>>       
>>>         
>>> +	for (i = 0; i < size; i++)
>>> +		cnt += sprintf(buf + cnt, "%02x", hash[i]);
>>> +	cnt += sprintf(buf + cnt, "\n");
>>> +
>>> +vfree_exit:
>>> +	vfree(hash);
>>> +	return ret ? : cnt;
>>>       
>>       
>> with simplification this should be
>>
>> return ret;
>>
>>       
>>>         
>>> +}
>>> +
>>> +#define to_sec_mgr(d) container_of(d, struct ifpga_sec_mgr, dev)
>>>       
>>       
>> Since this is used widely move closer to top of file.
> OK
>
>>       
>>>         
>>> +
>>> +#define DEVICE_ATTR_SEC_CSK(_name) \
>>> +static ssize_t _name##_canceled_csks_show(struct device *dev, \
>>> +					  struct device_attribute *attr, \
>>> +					  char *buf) \
>>> +{ \
>>> +	struct ifpga_sec_mgr *imgr = to_sec_mgr(dev); \
>>> +	return show_canceled_csk(imgr, \
>>> +	       imgr->iops->_name##_canceled_csks, \
>>> +	       imgr->iops->_name##_canceled_csk_nbits, buf); \
>>> +} \
>>> +static DEVICE_ATTR_RO(_name##_canceled_csks)
>>> +
>>> +#define DEVICE_ATTR_SEC_ROOT_ENTRY_HASH(_name) \
>>> +static ssize_t _name##_root_entry_hash_show(struct device *dev, \
>>> +				     struct device_attribute *attr, \
>>> +				     char *buf) \
>>> +{ \
>>> +	struct ifpga_sec_mgr *imgr = to_sec_mgr(dev); \
>>> +	return show_root_entry_hash(imgr, \
>>> +	       imgr->iops->_name##_root_entry_hash, \
>>> +	       imgr->iops->_name##_reh_size, buf); \
>>> +} \
>>> +static DEVICE_ATTR_RO(_name##_root_entry_hash)
>>> +
>>> +#define DEVICE_ATTR_SEC_FLASH_CNT(_name) \
>>> +static ssize_t _name##_flash_count_show(struct device *dev, \
>>> +		    struct device_attribute *attr, char *buf) \
>>> +{ \
>>> +	struct ifpga_sec_mgr *imgr = to_sec_mgr(dev); \
>>> +	int cnt = imgr->iops->_name##_flash_count(imgr); \
>>> +	return cnt < 0 ? cnt : sprintf(buf, "%d\n", cnt); \
>>> +} \
>>> +static DEVICE_ATTR_RO(_name##_flash_count)
>>> +
>>> +DEVICE_ATTR_SEC_ROOT_ENTRY_HASH(sr);
>>> +DEVICE_ATTR_SEC_ROOT_ENTRY_HASH(pr);
>>> +DEVICE_ATTR_SEC_ROOT_ENTRY_HASH(bmc);
>>> +DEVICE_ATTR_SEC_FLASH_CNT(user);
>>> +DEVICE_ATTR_SEC_FLASH_CNT(bmc);
>>> +DEVICE_ATTR_SEC_CSK(sr);
>>> +DEVICE_ATTR_SEC_CSK(pr);
>>> +DEVICE_ATTR_SEC_CSK(bmc);
>>> +
>>> +static struct attribute *sec_mgr_security_attrs[] = {
>>> +	&dev_attr_user_flash_count.attr,
>>> +	&dev_attr_bmc_flash_count.attr,
>>> +	&dev_attr_bmc_root_entry_hash.attr,
>>> +	&dev_attr_sr_root_entry_hash.attr,
>>> +	&dev_attr_pr_root_entry_hash.attr,
>>> +	&dev_attr_sr_canceled_csks.attr,
>>> +	&dev_attr_pr_canceled_csks.attr,
>>> +	&dev_attr_bmc_canceled_csks.attr,
>>> +	NULL,
>>> +};
>>> +
>>> +#define check_attr(attribute, _name) \
>>> +	((attribute) == &dev_attr_##_name.attr && imgr->iops->_name)
>>> +
>>> +static umode_t sec_mgr_visible(struct kobject *kobj,
>>> +			       struct attribute *attr, int n)
>>> +{
>>> +	struct ifpga_sec_mgr *imgr = to_sec_mgr(kobj_to_dev(kobj));
>>> +
>>> +	if (check_attr(attr, user_flash_count) ||
>>> +	    check_attr(attr, bmc_flash_count) ||
>>> +	    check_attr(attr, bmc_root_entry_hash) ||
>>> +	    check_attr(attr, sr_root_entry_hash) ||
>>> +	    check_attr(attr, pr_root_entry_hash) ||
>>> +	    check_attr(attr, sr_canceled_csks) ||
>>> +	    check_attr(attr, pr_canceled_csks) ||
>>> +	    check_attr(attr, bmc_canceled_csks))
>>> +		return attr->mode;
>>> +
>>>       
>>       
>> This is all or nothing, shouldn't the interface
>>
>> allow for null iop ?
> All or nothing? Each of the above attributes is optional and is enabled by
> providing a handler function. This is the "is_visible" op for sysfs and it
> ensures that only the enabled sysfs entries are displayed (any combination
> of enabled sysfs files).
>
> While these operations are all optional, there are some required operations in iops
> for the update process (in a later patch), so for the overall patchset iops
> cannot be NULL.
Ok. then add a comment.
>
>>       
>>>         
>>> +	return 0;
>>> +}
>>> +
>>> +static struct attribute_group sec_mgr_security_attr_group = {
>>> +	.name = "security",
>>> +	.attrs = sec_mgr_security_attrs,
>>> +	.is_visible = sec_mgr_visible,
>>> +};
>>> +
>>> +static ssize_t name_show(struct device *dev,
>>> +			 struct device_attribute *attr, char *buf)
>>> +{
>>> +	struct ifpga_sec_mgr *imgr = to_sec_mgr(dev);
>>> +
>>> +	return sprintf(buf, "%s\n", imgr->name);
>>> +}
>>> +static DEVICE_ATTR_RO(name);
>>> +
>>> +static struct attribute *sec_mgr_attrs[] = {
>>> +	&dev_attr_name.attr,
>>> +	NULL,
>>> +};
>>> +
>>> +static struct attribute_group sec_mgr_attr_group = {
>>> +	.attrs = sec_mgr_attrs,
>>> +};
>>> +
>>> +static const struct attribute_group *ifpga_sec_mgr_attr_groups[] = {
>>> +	&sec_mgr_attr_group,
>>> +	&sec_mgr_security_attr_group,
>>> +	NULL,
>>> +};
>>> +
>>> +static bool check_sysfs_handler(struct device *dev,
>>> +				void *sysfs_handler, void *size_handler,
>>> +				const char *sysfs_handler_name,
>>> +				const char *size_handler_name)
>>> +{
>>> +	if (sysfs_handler) {
>>>       
>>       
>> These two checks can be simplified to
>>
>> if (!sysfs_handler || !size_handler)
> That would require changes to the "else if" condition that follows, which
> assumes that syfs_handler is null. The purpose of this block of code is
> to ensure that if the size_handler or the sysfs_handler is defined, that
> they are both defined. It is OK if they are both undefined.
>
> If you wanted to reduce the code, I think we could do something like this, but
> but I'm afraid it might be confusing and less readable.
>
> if (!!size_handler != !!sysfs_handler) {
> 	dev_err(dev, "%s and %s must both be registered to enable the sysfs file\n",
> 		size_handler_name, sysfs_handler_name);
> 	return false;
> }
>
> What do you think?

The more creative uses of '!' the better. ;)

This is fine as-is, maybe add a comment.

>
>>       
>>>         
>>> +		if (!size_handler) {
>>> +			dev_err(dev, "%s registered without %s\n",
>>> +				sysfs_handler_name, size_handler_name);
>>> +			return false;
>>> +		}
>>> +	} else if (size_handler) {
>>> +		dev_err(dev, "%s registered without %s\n",
>>> +			size_handler_name, sysfs_handler_name);
>>> +		return false;
>>> +	}
>>> +	return true;
>>> +}
>>> +
>>> +#define check_reh_handler(_dev, _iops, _name) \
>>> +	check_sysfs_handler(_dev, (_iops)->_name##_root_entry_hash, \
>>> +			    (_iops)->_name##_reh_size, \
>>> +			    __stringify(_name##_root_entry_hash), \
>>> +			    __stringify(_name##_reh_size))
>>> +
>>> +#define check_csk_handler(_dev, _iops, _name) \
>>> +	check_sysfs_handler(_dev, (_iops)->_name##_canceled_csks, \
>>> +			    (_iops)->_name##_canceled_csk_nbits, \
>>> +			    __stringify(_name##_canceled_csks), \
>>> +			    __stringify(_name##_canceled_csk_nbits))
>>> +
>>> +/**
>>> + * ifpga_sec_mgr_register - register an IFPGA security manager struct
>>> + *
>>> + * @dev:  create ifpga security manager device from pdev
>>> + * @name: ifpga security manager name
>>> + * @iops: pointer to a structure of ifpga callback functions
>>> + * @priv: ifpga security manager private data
>>> + *
>>> + * Returns &struct ifpga_sec_mgr pointer on success, or ERR_PTR() on error.
>>> + */
>>> +struct ifpga_sec_mgr *
>>> +ifpga_sec_mgr_register(struct device *dev, const char *name,
>>> +		       const struct ifpga_sec_mgr_ops *iops, void *priv)
>>> +{
>>> +	struct ifpga_sec_mgr *imgr;
>>> +	int id, ret;
>>> +
>>> +	if (!check_reh_handler(dev, iops, bmc) ||
>>> +	    !check_reh_handler(dev, iops, sr) ||
>>> +	    !check_reh_handler(dev, iops, pr) ||
>>> +	    !check_csk_handler(dev, iops, bmc) ||
>>> +	    !check_csk_handler(dev, iops, sr) ||
>>> +	    !check_csk_handler(dev, iops, pr)) {
>>> +		return ERR_PTR(-EINVAL);
>>> +	}
>>> +
>>> +	if (!name || !strlen(name)) {
>>> +		dev_err(dev, "Attempt to register with no name!\n");
>>> +		return ERR_PTR(-EINVAL);
>>> +	}
>>> +
>>> +	imgr = kzalloc(sizeof(*imgr), GFP_KERNEL);
>>> +	if (!imgr)
>>> +		return ERR_PTR(-ENOMEM);
>>> +
>>> +	imgr->name = name;
>>>       
>>       
>> should name be dup-ed?
> The name is string constant that is provided by the underlying device driver
> (from the kernel space) so I don't think it would be necessary to dup the string.

If the underlying driver unloads, the name ptr will be invalid.

Will the driver unregister remove its use here ?

>
>>       
>>>         
>>> +	imgr->priv = priv;
>>> +	imgr->iops = iops;
>>> +	mutex_init(&imgr->lock);
>>> +
>>> +	id = ida_simple_get(&ifpga_sec_mgr_ida, 0, 0, GFP_KERNEL);
>>> +	if (id < 0) {
>>> +		ret = id;
>>> +		goto exit_free;
>>> +	}
>>> +
>>> +	imgr->dev.class = ifpga_sec_mgr_class;
>>> +	imgr->dev.parent = dev;
>>> +	imgr->dev.id = id;
>>> +
>>> +	ret = dev_set_name(&imgr->dev, "ifpga_sec%d", id);
>>> +	if (ret) {
>>> +		dev_err(dev, "Failed to set device name: ifpga_sec%d\n", id);
>>> +		ida_simple_remove(&ifpga_sec_mgr_ida, id);
>>> +		goto exit_free;
>>> +	}
>>> +
>>> +	ret = device_register(&imgr->dev);
>>> +	if (ret) {
>>> +		put_device(&imgr->dev);
>>> +		return ERR_PTR(ret);
>>> +	}
>>> +
>>> +	return imgr;
>>> +
>>> +exit_free:
>>> +	kfree(dev);
>>> +	return ERR_PTR(ret);
>>> +}
>>> +EXPORT_SYMBOL_GPL(ifpga_sec_mgr_register);
>>> +
>>> +/**
>>> + * ifpga_sec_mgr_unregister - unregister a IFPGA security manager
>>> + *
>>> + * @mgr: fpga manager struct
>>> + *
>>> + * This function is intended for use in a IFPGA security manager
>>> + * driver's remove() function.
>>> + */
>>> +void ifpga_sec_mgr_unregister(struct ifpga_sec_mgr *imgr)
>>> +{
>>> +	dev_info(&imgr->dev, "%s %s\n", __func__, imgr->name);
>>> +
>>> +	device_unregister(&imgr->dev);
>>> +}
>>> +EXPORT_SYMBOL_GPL(ifpga_sec_mgr_unregister);
>>> +
>>> +static void ifpga_sec_mgr_dev_release(struct device *dev)
>>> +{
>>> +	struct ifpga_sec_mgr *imgr = to_sec_mgr(dev);
>>> +
>>> +	mutex_destroy(&imgr->lock);
>>> +	ida_simple_remove(&ifpga_sec_mgr_ida, imgr->dev.id);
>>> +	kfree(imgr);
>>> +}
>>> +
>>> +static int __init ifpga_sec_mgr_class_init(void)
>>> +{
>>> +	pr_info("Intel FPGA Security Manager\n");
>>> +
>>> +	ifpga_sec_mgr_class = class_create(THIS_MODULE, "ifpga_sec_mgr");
>>> +	if (IS_ERR(ifpga_sec_mgr_class))
>>> +		return PTR_ERR(ifpga_sec_mgr_class);
>>> +
>>> +	ifpga_sec_mgr_class->dev_groups = ifpga_sec_mgr_attr_groups;
>>> +	ifpga_sec_mgr_class->dev_release = ifpga_sec_mgr_dev_release;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static void __exit ifpga_sec_mgr_class_exit(void)
>>> +{
>>> +	class_destroy(ifpga_sec_mgr_class);
>>> +	ida_destroy(&ifpga_sec_mgr_ida);
>>> +}
>>> +
>>> +MODULE_DESCRIPTION("Intel FPGA Security Manager Driver");
>>> +MODULE_LICENSE("GPL v2");
>>> +
>>> +subsys_initcall(ifpga_sec_mgr_class_init);
>>> +module_exit(ifpga_sec_mgr_class_exit)
>>> diff --git a/include/linux/fpga/ifpga-sec-mgr.h b/include/linux/fpga/ifpga-sec-mgr.h
>>> new file mode 100644
>>> index 000000000000..e391b0c8f448
>>> --- /dev/null
>>> +++ b/include/linux/fpga/ifpga-sec-mgr.h
>>> @@ -0,0 +1,145 @@
>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>> +/*
>>> + * Header file for Intel FPGA Security Manager
>>> + *
>>> + * Copyright (C) 2019-2020 Intel Corporation, Inc.
>>> + */
>>> +#ifndef _LINUX_IFPGA_SEC_MGR_H
>>> +#define _LINUX_IFPGA_SEC_MGR_H
>>> +
>>> +#include <linux/device.h>
>>> +#include <linux/mutex.h>
>>> +#include <linux/types.h>
>>> +
>>> +struct ifpga_sec_mgr;
>>> +
>>> +/**
>>> + * typedef sysfs_reh_size_t - Function to return byte size of root entry hash
>>> + *
>>> + * @imgr:      pointer to security manager structure
>>> + *
>>> + * This datatype is used to define a function that returns the byte size of a
>>> + * root entry hash.
>>> + *
>>> + * Context: No locking requirements are imposed by the security manager.
>>> + * Return:  Byte count on success, negative errno on failure
>>> + */
>>> +typedef int (*sysfs_reh_size_t)(struct ifpga_sec_mgr *imgr);
>>> +
>>> +/**
>>> + * typedef sysfs_reh_hndlr_t - Function pointer to sysfs file handler
>>> + *			       for root entry hashes
>>> + * @imgr:      pointer to security manager structure
>>> + * @hash:      pointer to an array of bytes in which to store the hash
>>> + * @size:      byte size of root entry hash
>>> + *
>>> + * This datatype is used to define a sysfs file handler function to
>>> + * return root entry hash data to be displayed via sysfs.
>>> + *
>>> + * Context: No locking requirements are imposed by the security manager.
>>> + * Return:  0 on success, negative errno on failure
>>> + */
>>> +typedef int (*sysfs_reh_hndlr_t)(struct ifpga_sec_mgr *imgr, u8 *hash,
>>> +				 unsigned int size);
>>> +
>>> +/**
>>> + * typedef sysfs_cnt_hndlr_t - Function pointer to sysfs file handler
>>> + *			       for flash counts
>>> + * @imgr: pointer to security manager structure
>>> + *
>>> + * This datatype is used to define a sysfs file handler function to
>>> + * return a flash count to be displayed via sysfs.
>>> + *
>>> + * Context: No locking requirements are imposed by the security manager
>>> + * Return: flash count or negative errno
>>> + */
>>> +typedef int (*sysfs_cnt_hndlr_t)(struct ifpga_sec_mgr *imgr);
>>> +
>>> +/**
>>> + * typedef sysfs_csk_nbits_t - Function to return the number of bits in
>>> + *				      a Code Signing Key cancellation vector
>>> + *
>>> + * @imgr:      pointer to security manager structure
>>> + *
>>> + * This datatype is used to define a function that returns the number of bits
>>> + * in a Code Signing Key cancellation vector.
>>> + *
>>> + * Context: No locking requirements are imposed by the security manager.
>>> + * Return:  Number of bits on success, negative errno on failure
>>> + */
>>> +typedef int (*sysfs_csk_nbits_t)(struct ifpga_sec_mgr *imgr);
>>> +
>>> +/**
>>> + * typedef sysfs_csk_hndlr_t - Function pointer to sysfs file handler
>>> + *			       bit vector of canceled keys
>>> + *
>>> + * @imgr:    pointer to security manager structure
>>> + * @csk_map: pointer to a bitmap to contain cancellation key vector
>>> + * @nbits:   number of bits in CSK vector
>>> + *
>>> + * This datatype is used to define a sysfs file handler function to
>>> + * return a bitmap of canceled keys to be displayed via sysfs.
>>> + *
>>> + * Context: No locking requirements are imposed by the security manager.
>>> + * Return:  0 on success, negative errno on failure
>>> + */
>>> +typedef int (*sysfs_csk_hndlr_t)(struct ifpga_sec_mgr *imgr,
>>> +				 unsigned long *csk_map, unsigned int nbits);
>>> +
>>> +/**
>>> + * struct ifpga_sec_mgr_ops - device specific operations
>>> + * @user_flash_count:	    Optional: Return sysfs string output for FPGA
>>> + *			    image flash count
>>> + * @bmc_flash_count:	    Optional: Return sysfs string output for BMC
>>> + *			    image flash count
>>> + * @sr_root_entry_hash:	    Optional: Return sysfs string output for static
>>> + *			    region root entry hash
>>> + * @pr_root_entry_hash:	    Optional: Return sysfs string output for partial
>>> + *			    reconfiguration root entry hash
>>> + * @bmc_root_entry_hash:    Optional: Return sysfs string output for BMC
>>> + *			    root entry hash
>>> + * @sr_canceled_csks:	    Optional: Return sysfs string output for static
>>> + *			    region canceled keys
>>> + * @pr_canceled_csks:	    Optional: Return sysfs string output for partial
>>> + *			    reconfiguration canceled keys
>>> + * @bmc_canceled_csks:	    Optional: Return sysfs string output for bmc
>>> + *			    canceled keys
>>> + * @bmc_canceled_csk_nbits: Optional: Return BMC canceled csk vector bit count
>>> + * @sr_canceled_csk_nbits:  Optional: Return SR canceled csk vector bit count
>>> + * @pr_canceled_csk_nbits:  Optional: Return PR canceled csk vector bit count
>>> + * @bmc_reh_size:	    Optional: Return byte size for BMC root entry hash
>>> + * @sr_reh_size:	    Optional: Return byte size for SR root entry hash
>>> + * @pr_reh_size:	    Optional: Return byte size for PR root entry hash
>>> + */
>>> +struct ifpga_sec_mgr_ops {
>>> +	sysfs_cnt_hndlr_t user_flash_count;
>>>       
>>       
>> These typedef's hide the function signatures and are
>>
>> not consistent with how the other headers in include/linux/fpga
>>
>> specify ops.
> OK - I can remove the typedefs.
>
>>       
>>>         
>>> +	sysfs_cnt_hndlr_t bmc_flash_count;
>>> +	sysfs_cnt_hndlr_t smbus_flash_count;
>>> +	sysfs_reh_hndlr_t sr_root_entry_hash;
>>> +	sysfs_reh_hndlr_t pr_root_entry_hash;
>>> +	sysfs_reh_hndlr_t bmc_root_entry_hash;
>>> +	sysfs_csk_hndlr_t sr_canceled_csks;
>>> +	sysfs_csk_hndlr_t pr_canceled_csks;
>>> +	sysfs_csk_hndlr_t bmc_canceled_csks;
>>> +	sysfs_reh_size_t bmc_reh_size;
>>> +	sysfs_reh_size_t sr_reh_size;
>>> +	sysfs_reh_size_t pr_reh_size;
>>> +	sysfs_csk_nbits_t bmc_canceled_csk_nbits;
>>> +	sysfs_csk_nbits_t sr_canceled_csk_nbits;
>>> +	sysfs_csk_nbits_t pr_canceled_csk_nbits;
>>> +};
>>> +
>>> +struct ifpga_sec_mgr {
>>> +	const char *name;
>>> +	struct device dev;
>>> +	const struct ifpga_sec_mgr_ops *iops;
>>> +	struct mutex lock;		/* protect data structure contents */
>>>       
>>       
>> comment is redundant for a lock.
> "scripts/checkpatch.pl --strict" will complain about mutex definitions that do not
> have a comment. Are you asking for a more descriptive comment? Or are you saying
> that the comment is not required?

Fine as-is.

If checkpatch wants it, just do it.

Tom

>
>> Tom
>>
>>       
>>>         
>>> +	void *priv;
>>> +};
>>> +
>>> +struct ifpga_sec_mgr *
>>> +ifpga_sec_mgr_register(struct device *dev, const char *name,
>>> +		       const struct ifpga_sec_mgr_ops *iops, void *priv);
>>> +void ifpga_sec_mgr_unregister(struct ifpga_sec_mgr *imgr);
>>> +
>>> +#endif
>>>       
>>     

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