1/*
2 * self test for change_page_attr.
3 *
4 * Clears the a test pte bit on random pages in the direct mapping,
5 * then reverts and compares page tables forwards and afterwards.
6 */
7#include <linux/bootmem.h>
8#include <linux/kthread.h>
9#include <linux/random.h>
10#include <linux/kernel.h>
11#include <linux/mm.h>
12
13#include <asm/cacheflush.h>
14#include <asm/pgtable.h>
15#include <asm/kdebug.h>
16
17/*
18 * Only print the results of the first pass:
19 */
20static __read_mostly int print = 1;
21
22enum {
23	NTEST			= 400,
24#ifdef CONFIG_X86_64
25	LPS			= (1 << PMD_SHIFT),
26#elif defined(CONFIG_X86_PAE)
27	LPS			= (1 << PMD_SHIFT),
28#else
29	LPS			= (1 << 22),
30#endif
31	GPS			= (1<<30)
32};
33
34#define PAGE_CPA_TEST	__pgprot(_PAGE_CPA_TEST)
35
36static int pte_testbit(pte_t pte)
37{
38	return pte_flags(pte) & _PAGE_SOFTW1;
39}
40
41struct split_state {
42	long lpg, gpg, spg, exec;
43	long min_exec, max_exec;
44};
45
46static int print_split(struct split_state *s)
47{
48	long i, expected, missed = 0;
49	int err = 0;
50
51	s->lpg = s->gpg = s->spg = s->exec = 0;
52	s->min_exec = ~0UL;
53	s->max_exec = 0;
54	for (i = 0; i < max_pfn_mapped; ) {
55		unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
56		unsigned int level;
57		pte_t *pte;
58
59		pte = lookup_address(addr, &level);
60		if (!pte) {
61			missed++;
62			i++;
63			continue;
64		}
65
66		if (level == PG_LEVEL_1G && sizeof(long) == 8) {
67			s->gpg++;
68			i += GPS/PAGE_SIZE;
69		} else if (level == PG_LEVEL_2M) {
70			if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
71				printk(KERN_ERR
72					"%lx level %d but not PSE %Lx\n",
73					addr, level, (u64)pte_val(*pte));
74				err = 1;
75			}
76			s->lpg++;
77			i += LPS/PAGE_SIZE;
78		} else {
79			s->spg++;
80			i++;
81		}
82		if (!(pte_val(*pte) & _PAGE_NX)) {
83			s->exec++;
84			if (addr < s->min_exec)
85				s->min_exec = addr;
86			if (addr > s->max_exec)
87				s->max_exec = addr;
88		}
89	}
90	if (print) {
91		printk(KERN_INFO
92			" 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
93			s->spg, s->lpg, s->gpg, s->exec,
94			s->min_exec != ~0UL ? s->min_exec : 0,
95			s->max_exec, missed);
96	}
97
98	expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
99	if (expected != i) {
100		printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
101			max_pfn_mapped, expected);
102		return 1;
103	}
104	return err;
105}
106
107static unsigned long addr[NTEST];
108static unsigned int len[NTEST];
109
110/* Change the global bit on random pages in the direct mapping */
111static int pageattr_test(void)
112{
113	struct split_state sa, sb, sc;
114	unsigned long *bm;
115	pte_t *pte, pte0;
116	int failed = 0;
117	unsigned int level;
118	int i, k;
119	int err;
120	unsigned long test_addr;
121
122	if (print)
123		printk(KERN_INFO "CPA self-test:\n");
124
125	bm = vzalloc((max_pfn_mapped + 7) / 8);
126	if (!bm) {
127		printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
128		return -ENOMEM;
129	}
130
131	failed += print_split(&sa);
132
133	for (i = 0; i < NTEST; i++) {
134		unsigned long pfn = prandom_u32() % max_pfn_mapped;
135
136		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
137		len[i] = prandom_u32() % 100;
138		len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
139
140		if (len[i] == 0)
141			len[i] = 1;
142
143		pte = NULL;
144		pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
145
146		for (k = 0; k < len[i]; k++) {
147			pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
148			if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
149			    !(pte_val(*pte) & _PAGE_PRESENT)) {
150				addr[i] = 0;
151				break;
152			}
153			if (k == 0) {
154				pte0 = *pte;
155			} else {
156				if (pgprot_val(pte_pgprot(*pte)) !=
157					pgprot_val(pte_pgprot(pte0))) {
158					len[i] = k;
159					break;
160				}
161			}
162			if (test_bit(pfn + k, bm)) {
163				len[i] = k;
164				break;
165			}
166			__set_bit(pfn + k, bm);
167		}
168		if (!addr[i] || !pte || !k) {
169			addr[i] = 0;
170			continue;
171		}
172
173		test_addr = addr[i];
174		err = change_page_attr_set(&test_addr, len[i], PAGE_CPA_TEST, 0);
175		if (err < 0) {
176			printk(KERN_ERR "CPA %d failed %d\n", i, err);
177			failed++;
178		}
179
180		pte = lookup_address(addr[i], &level);
181		if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
182			printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
183				pte ? (u64)pte_val(*pte) : 0ULL);
184			failed++;
185		}
186		if (level != PG_LEVEL_4K) {
187			printk(KERN_ERR "CPA %lx: unexpected level %d\n",
188				addr[i], level);
189			failed++;
190		}
191
192	}
193	vfree(bm);
194
195	failed += print_split(&sb);
196
197	for (i = 0; i < NTEST; i++) {
198		if (!addr[i])
199			continue;
200		pte = lookup_address(addr[i], &level);
201		if (!pte) {
202			printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
203			failed++;
204			continue;
205		}
206		test_addr = addr[i];
207		err = change_page_attr_clear(&test_addr, len[i], PAGE_CPA_TEST, 0);
208		if (err < 0) {
209			printk(KERN_ERR "CPA reverting failed: %d\n", err);
210			failed++;
211		}
212		pte = lookup_address(addr[i], &level);
213		if (!pte || pte_testbit(*pte)) {
214			printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
215				addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
216			failed++;
217		}
218
219	}
220
221	failed += print_split(&sc);
222
223	if (failed) {
224		WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
225		return -EINVAL;
226	} else {
227		if (print)
228			printk(KERN_INFO "ok.\n");
229	}
230
231	return 0;
232}
233
234static int do_pageattr_test(void *__unused)
235{
236	while (!kthread_should_stop()) {
237		schedule_timeout_interruptible(HZ*30);
238		if (pageattr_test() < 0)
239			break;
240		if (print)
241			print--;
242	}
243	return 0;
244}
245
246static int start_pageattr_test(void)
247{
248	struct task_struct *p;
249
250	p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
251	if (!IS_ERR(p))
252		wake_up_process(p);
253	else
254		WARN_ON(1);
255
256	return 0;
257}
258
259module_init(start_pageattr_test);
260