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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dummy_stm.c (2690B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * A dummy STM device for stm/stm_source class testing.
      4 * Copyright (c) 2014, Intel Corporation.
      5 *
      6 * STM class implements generic infrastructure for  System Trace Module devices
      7 * as defined in MIPI STPv2 specification.
      8 */
      9
     10#undef DEBUG
     11#include <linux/kernel.h>
     12#include <linux/module.h>
     13#include <linux/slab.h>
     14#include <linux/stm.h>
     15#include <uapi/linux/stm.h>
     16
     17static ssize_t notrace
     18dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
     19		 unsigned int channel, unsigned int packet, unsigned int flags,
     20		 unsigned int size, const unsigned char *payload)
     21{
     22#ifdef DEBUG
     23	u64 pl = 0;
     24
     25	if (payload)
     26		pl = *(u64 *)payload;
     27
     28	if (size < 8)
     29		pl &= (1ull << (size * 8)) - 1;
     30	trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel,
     31		     packet, size, pl);
     32#endif
     33	return size;
     34}
     35
     36#define DUMMY_STM_MAX 32
     37
     38static struct stm_data dummy_stm[DUMMY_STM_MAX];
     39
     40static int nr_dummies = 4;
     41
     42module_param(nr_dummies, int, 0400);
     43
     44static unsigned int fail_mode;
     45
     46module_param(fail_mode, int, 0600);
     47
     48static unsigned int master_min;
     49
     50module_param(master_min, int, 0400);
     51
     52static unsigned int master_max = STP_MASTER_MAX;
     53
     54module_param(master_max, int, 0400);
     55
     56static unsigned int nr_channels = STP_CHANNEL_MAX;
     57
     58module_param(nr_channels, int, 0400);
     59
     60static int dummy_stm_link(struct stm_data *data, unsigned int master,
     61			  unsigned int channel)
     62{
     63	if (fail_mode && (channel & fail_mode))
     64		return -EINVAL;
     65
     66	return 0;
     67}
     68
     69static int dummy_stm_init(void)
     70{
     71	int i, ret = -ENOMEM;
     72
     73	if (nr_dummies < 0 || nr_dummies > DUMMY_STM_MAX)
     74		return -EINVAL;
     75
     76	if (master_min > master_max ||
     77	    master_max > STP_MASTER_MAX ||
     78	    nr_channels > STP_CHANNEL_MAX)
     79		return -EINVAL;
     80
     81	for (i = 0; i < nr_dummies; i++) {
     82		dummy_stm[i].name = kasprintf(GFP_KERNEL, "dummy_stm.%d", i);
     83		if (!dummy_stm[i].name)
     84			goto fail_unregister;
     85
     86		dummy_stm[i].sw_start		= master_min;
     87		dummy_stm[i].sw_end		= master_max;
     88		dummy_stm[i].sw_nchannels	= nr_channels;
     89		dummy_stm[i].packet		= dummy_stm_packet;
     90		dummy_stm[i].link		= dummy_stm_link;
     91
     92		ret = stm_register_device(NULL, &dummy_stm[i], THIS_MODULE);
     93		if (ret)
     94			goto fail_free;
     95	}
     96
     97	return 0;
     98
     99fail_unregister:
    100	for (i--; i >= 0; i--) {
    101		stm_unregister_device(&dummy_stm[i]);
    102fail_free:
    103		kfree(dummy_stm[i].name);
    104	}
    105
    106	return ret;
    107
    108}
    109
    110static void dummy_stm_exit(void)
    111{
    112	int i;
    113
    114	for (i = 0; i < nr_dummies; i++) {
    115		stm_unregister_device(&dummy_stm[i]);
    116		kfree(dummy_stm[i].name);
    117	}
    118}
    119
    120module_init(dummy_stm_init);
    121module_exit(dummy_stm_exit);
    122
    123MODULE_LICENSE("GPL v2");
    124MODULE_DESCRIPTION("dummy_stm device");
    125MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");