1 files changed, 112 insertions, 0 deletions
diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
new file mode 100644
index 000000000..d0548e382
--- /dev/null
+++ b/mm/hwpoison-inject.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Inject a hwpoison memory failure on a arbitrary pfn */
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include <linux/hugetlb.h>
+#include "internal.h"
+
+static struct dentry *hwpoison_dir;
+
+static int hwpoison_inject(void *data, u64 val)
+{
+	unsigned long pfn = val;
+	struct page *p;
+	struct page *hpage;
+	int err;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!pfn_valid(pfn))
+		return -ENXIO;
+
+	p = pfn_to_page(pfn);
+	hpage = compound_head(p);
+
+	if (!hwpoison_filter_enable)
+		goto inject;
+
+	shake_page(hpage);
+	/*
+	 * This implies unable to support non-LRU pages except free page.
+	 */
+	if (!PageLRU(hpage) && !PageHuge(p) && !is_free_buddy_page(p))
+		return 0;
+
+	/*
+	 * do a racy check to make sure PG_hwpoison will only be set for
+	 * the targeted owner (or on a free page).
+	 * memory_failure() will redo the check reliably inside page lock.
+	 */
+	err = hwpoison_filter(hpage);
+	if (err)
+		return 0;
+
+inject:
+	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
+	err = memory_failure(pfn, MF_SW_SIMULATED);
+	return (err == -EOPNOTSUPP) ? 0 : err;
+}
+
+static int hwpoison_unpoison(void *data, u64 val)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	return unpoison_memory(val);
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
+DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
+
+static void __exit pfn_inject_exit(void)
+{
+	hwpoison_filter_enable = 0;
+	debugfs_remove_recursive(hwpoison_dir);
+}
+
+static int __init pfn_inject_init(void)
+{
+	hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
+
+	/*
+	 * Note that the below poison/unpoison interfaces do not involve
+	 * hardware status change, hence do not require hardware support.
+	 * They are mainly for testing hwpoison in software level.
+	 */
+	debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
+			    &hwpoison_fops);
+
+	debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
+			    &unpoison_fops);
+
+	debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
+			   &hwpoison_filter_enable);
+
+	debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
+			   &hwpoison_filter_dev_major);
+
+	debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
+			   &hwpoison_filter_dev_minor);
+
+	debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
+			   &hwpoison_filter_flags_mask);
+
+	debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
+			   &hwpoison_filter_flags_value);
+
+#ifdef CONFIG_MEMCG
+	debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
+			   &hwpoison_filter_memcg);
+#endif
+
+	return 0;
+}
+
+module_init(pfn_inject_init);
+module_exit(pfn_inject_exit);
+MODULE_LICENSE("GPL");