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  */
22 static __read_mostly int print = 1;
23 
24 enum {
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 
pte_testbit(pte_t pte)39 static int pte_testbit(pte_t pte)
40 {
41 	return pte_flags(pte) & _PAGE_SOFTW1;
42 }
43 
44 struct split_state {
45 	long lpg, gpg, spg, exec;
46 	long min_exec, max_exec;
47 };
48 
print_split(struct split_state * s)49 static 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 
110 static unsigned long addr[NTEST];
111 static unsigned int len[NTEST];
112 
113 static struct page *pages[NPAGES];
114 static unsigned long addrs[NPAGES];
115 
116 /* Change the global bit on random pages in the direct mapping */
pageattr_test(void)117 static 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 = prandom_u32_max(max_pfn_mapped);
140 
141 		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
142 		len[i] = prandom_u32_max(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 
do_pageattr_test(void * __unused)253 static 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 
start_pageattr_test(void)265 static 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 }
277 device_initcall(start_pageattr_test);
278