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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testmmiotrace.c (3255B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Written by Pekka Paalanen, 2008-2009 <pq@iki.fi>
      4 */
      5
      6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      7
      8#include <linux/module.h>
      9#include <linux/io.h>
     10#include <linux/mmiotrace.h>
     11#include <linux/security.h>
     12
     13static unsigned long mmio_address;
     14module_param_hw(mmio_address, ulong, iomem, 0);
     15MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
     16				"(or 8 MB if read_far is non-zero).");
     17
     18static unsigned long read_far = 0x400100;
     19module_param(read_far, ulong, 0);
     20MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
     21				"(default: 0x400100).");
     22
     23static unsigned v16(unsigned i)
     24{
     25	return i * 12 + 7;
     26}
     27
     28static unsigned v32(unsigned i)
     29{
     30	return i * 212371 + 13;
     31}
     32
     33static void do_write_test(void __iomem *p)
     34{
     35	unsigned int i;
     36	pr_info("write test.\n");
     37	mmiotrace_printk("Write test.\n");
     38
     39	for (i = 0; i < 256; i++)
     40		iowrite8(i, p + i);
     41
     42	for (i = 1024; i < (5 * 1024); i += 2)
     43		iowrite16(v16(i), p + i);
     44
     45	for (i = (5 * 1024); i < (16 * 1024); i += 4)
     46		iowrite32(v32(i), p + i);
     47}
     48
     49static void do_read_test(void __iomem *p)
     50{
     51	unsigned int i;
     52	unsigned errs[3] = { 0 };
     53	pr_info("read test.\n");
     54	mmiotrace_printk("Read test.\n");
     55
     56	for (i = 0; i < 256; i++)
     57		if (ioread8(p + i) != i)
     58			++errs[0];
     59
     60	for (i = 1024; i < (5 * 1024); i += 2)
     61		if (ioread16(p + i) != v16(i))
     62			++errs[1];
     63
     64	for (i = (5 * 1024); i < (16 * 1024); i += 4)
     65		if (ioread32(p + i) != v32(i))
     66			++errs[2];
     67
     68	mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
     69						errs[0], errs[1], errs[2]);
     70}
     71
     72static void do_read_far_test(void __iomem *p)
     73{
     74	pr_info("read far test.\n");
     75	mmiotrace_printk("Read far test.\n");
     76
     77	ioread32(p + read_far);
     78}
     79
     80static void do_test(unsigned long size)
     81{
     82	void __iomem *p = ioremap(mmio_address, size);
     83	if (!p) {
     84		pr_err("could not ioremap, aborting.\n");
     85		return;
     86	}
     87	mmiotrace_printk("ioremap returned %p.\n", p);
     88	do_write_test(p);
     89	do_read_test(p);
     90	if (read_far && read_far < size - 4)
     91		do_read_far_test(p);
     92	iounmap(p);
     93}
     94
     95/*
     96 * Tests how mmiotrace behaves in face of multiple ioremap / iounmaps in
     97 * a short time. We had a bug in deferred freeing procedure which tried
     98 * to free this region multiple times (ioremap can reuse the same address
     99 * for many mappings).
    100 */
    101static void do_test_bulk_ioremapping(void)
    102{
    103	void __iomem *p;
    104	int i;
    105
    106	for (i = 0; i < 10; ++i) {
    107		p = ioremap(mmio_address, PAGE_SIZE);
    108		if (p)
    109			iounmap(p);
    110	}
    111
    112	/* Force freeing. If it will crash we will know why. */
    113	synchronize_rcu();
    114}
    115
    116static int __init init(void)
    117{
    118	unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
    119	int ret = security_locked_down(LOCKDOWN_MMIOTRACE);
    120
    121	if (ret)
    122		return ret;
    123
    124	if (mmio_address == 0) {
    125		pr_err("you have to use the module argument mmio_address.\n");
    126		pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!\n");
    127		return -ENXIO;
    128	}
    129
    130	pr_warn("WARNING: mapping %lu kB @ 0x%08lx in PCI address space, "
    131		"and writing 16 kB of rubbish in there.\n",
    132		size >> 10, mmio_address);
    133	do_test(size);
    134	do_test_bulk_ioremapping();
    135	pr_info("All done.\n");
    136	return 0;
    137}
    138
    139static void __exit cleanup(void)
    140{
    141	pr_debug("unloaded.\n");
    142}
    143
    144module_init(init);
    145module_exit(cleanup);
    146MODULE_LICENSE("GPL");