1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/mm.h>
 3#include <linux/page-isolation.h>
 4
 5unsigned int _debug_guardpage_minorder;
 6
 7bool _debug_pagealloc_enabled_early __read_mostly
 8			= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
 9EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
10DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
11EXPORT_SYMBOL(_debug_pagealloc_enabled);
12
13DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
14
15static int __init early_debug_pagealloc(char *buf)
16{
17	return kstrtobool(buf, &_debug_pagealloc_enabled_early);
18}
19early_param("debug_pagealloc", early_debug_pagealloc);
20
21static int __init debug_guardpage_minorder_setup(char *buf)
22{
23	unsigned long res;
24
25	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_PAGE_ORDER / 2) {
26		pr_err("Bad debug_guardpage_minorder value\n");
27		return 0;
28	}
29	_debug_guardpage_minorder = res;
30	pr_info("Setting debug_guardpage_minorder to %lu\n", res);
31	return 0;
32}
33early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
34
35bool __set_page_guard(struct zone *zone, struct page *page, unsigned int order)
36{
37	if (order >= debug_guardpage_minorder())
38		return false;
39
40	__SetPageGuard(page);
41	INIT_LIST_HEAD(&page->buddy_list);
42	set_page_private(page, order);
43
44	return true;
45}
46
47void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order)
48{
49	__ClearPageGuard(page);
50	set_page_private(page, 0);
51}