cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sysfs.c (3190B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* Copyright(c) 2022 Intel Corporation. */
      3
      4#include <linux/cpu.h>
      5#include <linux/delay.h>
      6#include <linux/fs.h>
      7#include <linux/semaphore.h>
      8#include <linux/slab.h>
      9
     10#include "ifs.h"
     11
     12/*
     13 * Protects against simultaneous tests on multiple cores, or
     14 * reloading can file while a test is in progress
     15 */
     16DEFINE_SEMAPHORE(ifs_sem);
     17
     18/*
     19 * The sysfs interface to check additional details of last test
     20 * cat /sys/devices/system/platform/ifs/details
     21 */
     22static ssize_t details_show(struct device *dev,
     23			    struct device_attribute *attr,
     24			    char *buf)
     25{
     26	struct ifs_data *ifsd = ifs_get_data(dev);
     27
     28	return sysfs_emit(buf, "%#llx\n", ifsd->scan_details);
     29}
     30
     31static DEVICE_ATTR_RO(details);
     32
     33static const char * const status_msg[] = {
     34	[SCAN_NOT_TESTED] = "untested",
     35	[SCAN_TEST_PASS] = "pass",
     36	[SCAN_TEST_FAIL] = "fail"
     37};
     38
     39/*
     40 * The sysfs interface to check the test status:
     41 * To check the status of last test
     42 * cat /sys/devices/platform/ifs/status
     43 */
     44static ssize_t status_show(struct device *dev,
     45			   struct device_attribute *attr,
     46			   char *buf)
     47{
     48	struct ifs_data *ifsd = ifs_get_data(dev);
     49
     50	return sysfs_emit(buf, "%s\n", status_msg[ifsd->status]);
     51}
     52
     53static DEVICE_ATTR_RO(status);
     54
     55/*
     56 * The sysfs interface for single core testing
     57 * To start test, for example, cpu5
     58 * echo 5 > /sys/devices/platform/ifs/run_test
     59 * To check the result:
     60 * cat /sys/devices/platform/ifs/result
     61 * The sibling core gets tested at the same time.
     62 */
     63static ssize_t run_test_store(struct device *dev,
     64			      struct device_attribute *attr,
     65			      const char *buf, size_t count)
     66{
     67	struct ifs_data *ifsd = ifs_get_data(dev);
     68	unsigned int cpu;
     69	int rc;
     70
     71	rc = kstrtouint(buf, 0, &cpu);
     72	if (rc < 0 || cpu >= nr_cpu_ids)
     73		return -EINVAL;
     74
     75	if (down_interruptible(&ifs_sem))
     76		return -EINTR;
     77
     78	if (!ifsd->loaded)
     79		rc = -EPERM;
     80	else
     81		rc = do_core_test(cpu, dev);
     82
     83	up(&ifs_sem);
     84
     85	return rc ? rc : count;
     86}
     87
     88static DEVICE_ATTR_WO(run_test);
     89
     90/*
     91 * Reload the IFS image. When user wants to install new IFS image
     92 */
     93static ssize_t reload_store(struct device *dev,
     94			    struct device_attribute *attr,
     95			    const char *buf, size_t count)
     96{
     97	struct ifs_data *ifsd = ifs_get_data(dev);
     98	bool res;
     99
    100
    101	if (kstrtobool(buf, &res))
    102		return -EINVAL;
    103	if (!res)
    104		return count;
    105
    106	if (down_interruptible(&ifs_sem))
    107		return -EINTR;
    108
    109	ifs_load_firmware(dev);
    110
    111	up(&ifs_sem);
    112
    113	return ifsd->loaded ? count : -ENODEV;
    114}
    115
    116static DEVICE_ATTR_WO(reload);
    117
    118/*
    119 * Display currently loaded IFS image version.
    120 */
    121static ssize_t image_version_show(struct device *dev,
    122				  struct device_attribute *attr, char *buf)
    123{
    124	struct ifs_data *ifsd = ifs_get_data(dev);
    125
    126	if (!ifsd->loaded)
    127		return sysfs_emit(buf, "%s\n", "none");
    128	else
    129		return sysfs_emit(buf, "%#x\n", ifsd->loaded_version);
    130}
    131
    132static DEVICE_ATTR_RO(image_version);
    133
    134/* global scan sysfs attributes */
    135static struct attribute *plat_ifs_attrs[] = {
    136	&dev_attr_details.attr,
    137	&dev_attr_status.attr,
    138	&dev_attr_run_test.attr,
    139	&dev_attr_reload.attr,
    140	&dev_attr_image_version.attr,
    141	NULL
    142};
    143
    144ATTRIBUTE_GROUPS(plat_ifs);
    145
    146const struct attribute_group **ifs_get_groups(void)
    147{
    148	return plat_ifs_groups;
    149}