xref: /kernel/linux/linux-6.6/arch/x86/mm/pat/cpa-test.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * self test for change_page_attr.
4 *
5 * Clears the a test pte bit on random pages in the direct mapping,
6 * then reverts and compares page tables forwards and afterwards.
7 */
8#include <linux/memblock.h>
9#include <linux/kthread.h>
10#include <linux/random.h>
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/mm.h>
14#include <linux/vmalloc.h>
15
16#include <asm/cacheflush.h>
17#include <asm/kdebug.h>
18
19/*
20 * Only print the results of the first pass:
21 */
22static __read_mostly int print = 1;
23
24enum {
25	NTEST			= 3 * 100,
26	NPAGES			= 100,
27#ifdef CONFIG_X86_64
28	LPS			= (1 << PMD_SHIFT),
29#elif defined(CONFIG_X86_PAE)
30	LPS			= (1 << PMD_SHIFT),
31#else
32	LPS			= (1 << 22),
33#endif
34	GPS			= (1<<30)
35};
36
37#define PAGE_CPA_TEST	__pgprot(_PAGE_CPA_TEST)
38
39static int pte_testbit(pte_t pte)
40{
41	return pte_flags(pte) & _PAGE_SOFTW1;
42}
43
44struct split_state {
45	long lpg, gpg, spg, exec;
46	long min_exec, max_exec;
47};
48
49static int print_split(struct split_state *s)
50{
51	long i, expected, missed = 0;
52	int err = 0;
53
54	s->lpg = s->gpg = s->spg = s->exec = 0;
55	s->min_exec = ~0UL;
56	s->max_exec = 0;
57	for (i = 0; i < max_pfn_mapped; ) {
58		unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
59		unsigned int level;
60		pte_t *pte;
61
62		pte = lookup_address(addr, &level);
63		if (!pte) {
64			missed++;
65			i++;
66			continue;
67		}
68
69		if (level == PG_LEVEL_1G && sizeof(long) == 8) {
70			s->gpg++;
71			i += GPS/PAGE_SIZE;
72		} else if (level == PG_LEVEL_2M) {
73			if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
74				printk(KERN_ERR
75					"%lx level %d but not PSE %Lx\n",
76					addr, level, (u64)pte_val(*pte));
77				err = 1;
78			}
79			s->lpg++;
80			i += LPS/PAGE_SIZE;
81		} else {
82			s->spg++;
83			i++;
84		}
85		if (!(pte_val(*pte) & _PAGE_NX)) {
86			s->exec++;
87			if (addr < s->min_exec)
88				s->min_exec = addr;
89			if (addr > s->max_exec)
90				s->max_exec = addr;
91		}
92	}
93	if (print) {
94		printk(KERN_INFO
95			" 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
96			s->spg, s->lpg, s->gpg, s->exec,
97			s->min_exec != ~0UL ? s->min_exec : 0,
98			s->max_exec, missed);
99	}
100
101	expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
102	if (expected != i) {
103		printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
104			max_pfn_mapped, expected);
105		return 1;
106	}
107	return err;
108}
109
110static unsigned long addr[NTEST];
111static unsigned int len[NTEST];
112
113static struct page *pages[NPAGES];
114static unsigned long addrs[NPAGES];
115
116/* Change the global bit on random pages in the direct mapping */
117static int pageattr_test(void)
118{
119	struct split_state sa, sb, sc;
120	unsigned long *bm;
121	pte_t *pte, pte0;
122	int failed = 0;
123	unsigned int level;
124	int i, k;
125	int err;
126
127	if (print)
128		printk(KERN_INFO "CPA self-test:\n");
129
130	bm = vzalloc((max_pfn_mapped + 7) / 8);
131	if (!bm) {
132		printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
133		return -ENOMEM;
134	}
135
136	failed += print_split(&sa);
137
138	for (i = 0; i < NTEST; i++) {
139		unsigned long pfn = get_random_u32_below(max_pfn_mapped);
140
141		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
142		len[i] = get_random_u32_below(NPAGES);
143		len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
144
145		if (len[i] == 0)
146			len[i] = 1;
147
148		pte = NULL;
149		pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
150
151		for (k = 0; k < len[i]; k++) {
152			pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
153			if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
154			    !(pte_val(*pte) & _PAGE_PRESENT)) {
155				addr[i] = 0;
156				break;
157			}
158			if (k == 0) {
159				pte0 = *pte;
160			} else {
161				if (pgprot_val(pte_pgprot(*pte)) !=
162					pgprot_val(pte_pgprot(pte0))) {
163					len[i] = k;
164					break;
165				}
166			}
167			if (test_bit(pfn + k, bm)) {
168				len[i] = k;
169				break;
170			}
171			__set_bit(pfn + k, bm);
172			addrs[k] = addr[i] + k*PAGE_SIZE;
173			pages[k] = pfn_to_page(pfn + k);
174		}
175		if (!addr[i] || !pte || !k) {
176			addr[i] = 0;
177			continue;
178		}
179
180		switch (i % 3) {
181		case 0:
182			err = change_page_attr_set(&addr[i], len[i], PAGE_CPA_TEST, 0);
183			break;
184
185		case 1:
186			err = change_page_attr_set(addrs, len[1], PAGE_CPA_TEST, 1);
187			break;
188
189		case 2:
190			err = cpa_set_pages_array(pages, len[i], PAGE_CPA_TEST);
191			break;
192		}
193
194
195		if (err < 0) {
196			printk(KERN_ERR "CPA %d failed %d\n", i, err);
197			failed++;
198		}
199
200		pte = lookup_address(addr[i], &level);
201		if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
202			printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
203				pte ? (u64)pte_val(*pte) : 0ULL);
204			failed++;
205		}
206		if (level != PG_LEVEL_4K) {
207			printk(KERN_ERR "CPA %lx: unexpected level %d\n",
208				addr[i], level);
209			failed++;
210		}
211
212	}
213	vfree(bm);
214
215	failed += print_split(&sb);
216
217	for (i = 0; i < NTEST; i++) {
218		if (!addr[i])
219			continue;
220		pte = lookup_address(addr[i], &level);
221		if (!pte) {
222			printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
223			failed++;
224			continue;
225		}
226		err = change_page_attr_clear(&addr[i], len[i], PAGE_CPA_TEST, 0);
227		if (err < 0) {
228			printk(KERN_ERR "CPA reverting failed: %d\n", err);
229			failed++;
230		}
231		pte = lookup_address(addr[i], &level);
232		if (!pte || pte_testbit(*pte)) {
233			printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
234				addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
235			failed++;
236		}
237
238	}
239
240	failed += print_split(&sc);
241
242	if (failed) {
243		WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
244		return -EINVAL;
245	} else {
246		if (print)
247			printk(KERN_INFO "ok.\n");
248	}
249
250	return 0;
251}
252
253static int do_pageattr_test(void *__unused)
254{
255	while (!kthread_should_stop()) {
256		schedule_timeout_interruptible(HZ*30);
257		if (pageattr_test() < 0)
258			break;
259		if (print)
260			print--;
261	}
262	return 0;
263}
264
265static int start_pageattr_test(void)
266{
267	struct task_struct *p;
268
269	p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
270	if (!IS_ERR(p))
271		wake_up_process(p);
272	else
273		WARN_ON(1);
274
275	return 0;
276}
277device_initcall(start_pageattr_test);
278