Commit 6f33a92b authored by Jithu Joseph's avatar Jithu Joseph Committed by Hans de Goede
Browse files

platform/x86/intel/ifs: Add IFS sysfs interface 



Implement sysfs interface to trigger ifs test for a specific cpu.
Additional interfaces related to checking the status of the
scan test and seeing the version of the loaded IFS binary
are also added.

The basic usage is as below.
   - To start test, for example on cpu5:
       echo 5 > /sys/devices/platform/intel_ifs/run_test
   - To see the status of the last test
       cat /sys/devices/platform/intel_ifs/status
   - To see the version of the loaded scan binary
       cat /sys/devices/platform/intel_ifs/image_version

Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJithu Joseph <jithu.joseph@intel.com>
Co-developed-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Acked-by: default avatarHans de Goede <hdegoede@redhat.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220506225410.1652287-10-tony.luck@intel.com


Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
parent 2b40e654

drivers/platform/x86/intel/ifs/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_INTEL_IFS)		+= intel_ifs.o



intel_ifs-objs			:= core.o load.o runtest.o
 
intel_ifs-objs			:= core.o load.o runtest.o sysfs.o

drivers/platform/x86/intel/ifs/core.c

+5 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 


#include <linux/module.h>

#include <linux/kdev_t.h>

#include <linux/semaphore.h>



#include <asm/cpu_device_id.h>
@@ -47,9 +48,13 @@ static int __init ifs_init(void) 
	if (rdmsrl_safe(MSR_INTEGRITY_CAPS, &msrval))

		return -ENODEV;



	ifs_device.misc.groups = ifs_get_groups();



	if ((msrval & BIT(ifs_device.data.integrity_cap_bit)) &&

	    !misc_register(&ifs_device.misc)) {

		down(&ifs_sem);

		ifs_load_firmware(ifs_device.misc.this_device);

		up(&ifs_sem);

		return 0;

	}

drivers/platform/x86/intel/ifs/ifs.h

+3 −0
Original line number Diff line number Diff line
@@ -117,5 +117,8 @@ static inline struct ifs_data *ifs_get_data(struct device *dev) 


void ifs_load_firmware(struct device *dev);

int do_core_test(int cpu, struct device *dev);

const struct attribute_group **ifs_get_groups(void);



extern struct semaphore ifs_sem;



#endif

drivers/platform/x86/intel/ifs/sysfs.c

0 → 100644
+149 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Copyright(c) 2022 Intel Corporation. */



#include <linux/cpu.h>

#include <linux/delay.h>

#include <linux/fs.h>

#include <linux/semaphore.h>

#include <linux/slab.h>



#include "ifs.h"



/*

 * Protects against simultaneous tests on multiple cores, or

 * reloading can file while a test is in progress

 */

DEFINE_SEMAPHORE(ifs_sem);



/*

 * The sysfs interface to check additional details of last test

 * cat /sys/devices/system/platform/ifs/details

 */

static ssize_t details_show(struct device *dev,

			    struct device_attribute *attr,

			    char *buf)

{

	struct ifs_data *ifsd = ifs_get_data(dev);



	return sysfs_emit(buf, "%#llx\n", ifsd->scan_details);

}



static DEVICE_ATTR_RO(details);



static const char * const status_msg[] = {

	[SCAN_NOT_TESTED] = "untested",

	[SCAN_TEST_PASS] = "pass",

	[SCAN_TEST_FAIL] = "fail"

};



/*

 * The sysfs interface to check the test status:

 * To check the status of last test

 * cat /sys/devices/platform/ifs/status

 */

static ssize_t status_show(struct device *dev,

			   struct device_attribute *attr,

			   char *buf)

{

	struct ifs_data *ifsd = ifs_get_data(dev);



	return sysfs_emit(buf, "%s\n", status_msg[ifsd->status]);

}



static DEVICE_ATTR_RO(status);



/*

 * The sysfs interface for single core testing

 * To start test, for example, cpu5

 * echo 5 > /sys/devices/platform/ifs/run_test

 * To check the result:

 * cat /sys/devices/platform/ifs/result

 * The sibling core gets tested at the same time.

 */

static ssize_t run_test_store(struct device *dev,

			      struct device_attribute *attr,

			      const char *buf, size_t count)

{

	struct ifs_data *ifsd = ifs_get_data(dev);

	unsigned int cpu;

	int rc;



	rc = kstrtouint(buf, 0, &cpu);

	if (rc < 0 || cpu >= nr_cpu_ids)

		return -EINVAL;



	if (down_interruptible(&ifs_sem))

		return -EINTR;



	if (!ifsd->loaded)

		rc = -EPERM;

	else

		rc = do_core_test(cpu, dev);



	up(&ifs_sem);



	return rc ? rc : count;

}



static DEVICE_ATTR_WO(run_test);



/*

 * Reload the IFS image. When user wants to install new IFS image

 */

static ssize_t reload_store(struct device *dev,

			    struct device_attribute *attr,

			    const char *buf, size_t count)

{

	struct ifs_data *ifsd = ifs_get_data(dev);

	bool res;





	if (kstrtobool(buf, &res))

		return -EINVAL;

	if (!res)

		return count;



	if (down_interruptible(&ifs_sem))

		return -EINTR;



	ifs_load_firmware(dev);



	up(&ifs_sem);



	return ifsd->loaded ? count : -ENODEV;

}



static DEVICE_ATTR_WO(reload);



/*

 * Display currently loaded IFS image version.

 */

static ssize_t image_version_show(struct device *dev,

				  struct device_attribute *attr, char *buf)

{

	struct ifs_data *ifsd = ifs_get_data(dev);



	if (!ifsd->loaded)

		return sysfs_emit(buf, "%s\n", "none");

	else

		return sysfs_emit(buf, "%#x\n", ifsd->loaded_version);

}



static DEVICE_ATTR_RO(image_version);



/* global scan sysfs attributes */

static struct attribute *plat_ifs_attrs[] = {

	&dev_attr_details.attr,

	&dev_attr_status.attr,

	&dev_attr_run_test.attr,

	&dev_attr_reload.attr,

	&dev_attr_image_version.attr,

	NULL

};



ATTRIBUTE_GROUPS(plat_ifs);



const struct attribute_group **ifs_get_groups(void)

{

	return plat_ifs_groups;

}