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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hwpoison-inject.c (2815B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* Inject a hwpoison memory failure on a arbitrary pfn */
      3#include <linux/module.h>
      4#include <linux/debugfs.h>
      5#include <linux/kernel.h>
      6#include <linux/mm.h>
      7#include <linux/swap.h>
      8#include <linux/pagemap.h>
      9#include <linux/hugetlb.h>
     10#include "internal.h"
     11
     12static struct dentry *hwpoison_dir;
     13
     14static int hwpoison_inject(void *data, u64 val)
     15{
     16	unsigned long pfn = val;
     17	struct page *p;
     18	struct page *hpage;
     19	int err;
     20
     21	if (!capable(CAP_SYS_ADMIN))
     22		return -EPERM;
     23
     24	if (!pfn_valid(pfn))
     25		return -ENXIO;
     26
     27	p = pfn_to_page(pfn);
     28	hpage = compound_head(p);
     29
     30	if (!hwpoison_filter_enable)
     31		goto inject;
     32
     33	shake_page(hpage);
     34	/*
     35	 * This implies unable to support non-LRU pages except free page.
     36	 */
     37	if (!PageLRU(hpage) && !PageHuge(p) && !is_free_buddy_page(p))
     38		return 0;
     39
     40	/*
     41	 * do a racy check to make sure PG_hwpoison will only be set for
     42	 * the targeted owner (or on a free page).
     43	 * memory_failure() will redo the check reliably inside page lock.
     44	 */
     45	err = hwpoison_filter(hpage);
     46	if (err)
     47		return 0;
     48
     49inject:
     50	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
     51	err = memory_failure(pfn, MF_SW_SIMULATED);
     52	return (err == -EOPNOTSUPP) ? 0 : err;
     53}
     54
     55static int hwpoison_unpoison(void *data, u64 val)
     56{
     57	if (!capable(CAP_SYS_ADMIN))
     58		return -EPERM;
     59
     60	return unpoison_memory(val);
     61}
     62
     63DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
     64DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
     65
     66static void pfn_inject_exit(void)
     67{
     68	hwpoison_filter_enable = 0;
     69	debugfs_remove_recursive(hwpoison_dir);
     70}
     71
     72static int pfn_inject_init(void)
     73{
     74	hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
     75
     76	/*
     77	 * Note that the below poison/unpoison interfaces do not involve
     78	 * hardware status change, hence do not require hardware support.
     79	 * They are mainly for testing hwpoison in software level.
     80	 */
     81	debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
     82			    &hwpoison_fops);
     83
     84	debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
     85			    &unpoison_fops);
     86
     87	debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
     88			   &hwpoison_filter_enable);
     89
     90	debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
     91			   &hwpoison_filter_dev_major);
     92
     93	debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
     94			   &hwpoison_filter_dev_minor);
     95
     96	debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
     97			   &hwpoison_filter_flags_mask);
     98
     99	debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
    100			   &hwpoison_filter_flags_value);
    101
    102#ifdef CONFIG_MEMCG
    103	debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
    104			   &hwpoison_filter_memcg);
    105#endif
    106
    107	return 0;
    108}
    109
    110module_init(pfn_inject_init);
    111module_exit(pfn_inject_exit);
    112MODULE_LICENSE("GPL");