xref: /openbmc/linux/arch/x86/mm/pat/cpa-test.c (revision 6c33a6f4)
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/pgtable.h>
18 #include <asm/kdebug.h>
19 
20 /*
21  * Only print the results of the first pass:
22  */
23 static __read_mostly int print = 1;
24 
25 enum {
26 	NTEST			= 3 * 100,
27 	NPAGES			= 100,
28 #ifdef CONFIG_X86_64
29 	LPS			= (1 << PMD_SHIFT),
30 #elif defined(CONFIG_X86_PAE)
31 	LPS			= (1 << PMD_SHIFT),
32 #else
33 	LPS			= (1 << 22),
34 #endif
35 	GPS			= (1<<30)
36 };
37 
38 #define PAGE_CPA_TEST	__pgprot(_PAGE_CPA_TEST)
39 
40 static int pte_testbit(pte_t pte)
41 {
42 	return pte_flags(pte) & _PAGE_SOFTW1;
43 }
44 
45 struct split_state {
46 	long lpg, gpg, spg, exec;
47 	long min_exec, max_exec;
48 };
49 
50 static int print_split(struct split_state *s)
51 {
52 	long i, expected, missed = 0;
53 	int err = 0;
54 
55 	s->lpg = s->gpg = s->spg = s->exec = 0;
56 	s->min_exec = ~0UL;
57 	s->max_exec = 0;
58 	for (i = 0; i < max_pfn_mapped; ) {
59 		unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
60 		unsigned int level;
61 		pte_t *pte;
62 
63 		pte = lookup_address(addr, &level);
64 		if (!pte) {
65 			missed++;
66 			i++;
67 			continue;
68 		}
69 
70 		if (level == PG_LEVEL_1G && sizeof(long) == 8) {
71 			s->gpg++;
72 			i += GPS/PAGE_SIZE;
73 		} else if (level == PG_LEVEL_2M) {
74 			if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
75 				printk(KERN_ERR
76 					"%lx level %d but not PSE %Lx\n",
77 					addr, level, (u64)pte_val(*pte));
78 				err = 1;
79 			}
80 			s->lpg++;
81 			i += LPS/PAGE_SIZE;
82 		} else {
83 			s->spg++;
84 			i++;
85 		}
86 		if (!(pte_val(*pte) & _PAGE_NX)) {
87 			s->exec++;
88 			if (addr < s->min_exec)
89 				s->min_exec = addr;
90 			if (addr > s->max_exec)
91 				s->max_exec = addr;
92 		}
93 	}
94 	if (print) {
95 		printk(KERN_INFO
96 			" 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
97 			s->spg, s->lpg, s->gpg, s->exec,
98 			s->min_exec != ~0UL ? s->min_exec : 0,
99 			s->max_exec, missed);
100 	}
101 
102 	expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
103 	if (expected != i) {
104 		printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
105 			max_pfn_mapped, expected);
106 		return 1;
107 	}
108 	return err;
109 }
110 
111 static unsigned long addr[NTEST];
112 static unsigned int len[NTEST];
113 
114 static struct page *pages[NPAGES];
115 static unsigned long addrs[NPAGES];
116 
117 /* Change the global bit on random pages in the direct mapping */
118 static int pageattr_test(void)
119 {
120 	struct split_state sa, sb, sc;
121 	unsigned long *bm;
122 	pte_t *pte, pte0;
123 	int failed = 0;
124 	unsigned int level;
125 	int i, k;
126 	int err;
127 
128 	if (print)
129 		printk(KERN_INFO "CPA self-test:\n");
130 
131 	bm = vzalloc((max_pfn_mapped + 7) / 8);
132 	if (!bm) {
133 		printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
134 		return -ENOMEM;
135 	}
136 
137 	failed += print_split(&sa);
138 
139 	for (i = 0; i < NTEST; i++) {
140 		unsigned long pfn = prandom_u32() % max_pfn_mapped;
141 
142 		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
143 		len[i] = prandom_u32() % NPAGES;
144 		len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
145 
146 		if (len[i] == 0)
147 			len[i] = 1;
148 
149 		pte = NULL;
150 		pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
151 
152 		for (k = 0; k < len[i]; k++) {
153 			pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
154 			if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
155 			    !(pte_val(*pte) & _PAGE_PRESENT)) {
156 				addr[i] = 0;
157 				break;
158 			}
159 			if (k == 0) {
160 				pte0 = *pte;
161 			} else {
162 				if (pgprot_val(pte_pgprot(*pte)) !=
163 					pgprot_val(pte_pgprot(pte0))) {
164 					len[i] = k;
165 					break;
166 				}
167 			}
168 			if (test_bit(pfn + k, bm)) {
169 				len[i] = k;
170 				break;
171 			}
172 			__set_bit(pfn + k, bm);
173 			addrs[k] = addr[i] + k*PAGE_SIZE;
174 			pages[k] = pfn_to_page(pfn + k);
175 		}
176 		if (!addr[i] || !pte || !k) {
177 			addr[i] = 0;
178 			continue;
179 		}
180 
181 		switch (i % 3) {
182 		case 0:
183 			err = change_page_attr_set(&addr[i], len[i], PAGE_CPA_TEST, 0);
184 			break;
185 
186 		case 1:
187 			err = change_page_attr_set(addrs, len[1], PAGE_CPA_TEST, 1);
188 			break;
189 
190 		case 2:
191 			err = cpa_set_pages_array(pages, len[i], PAGE_CPA_TEST);
192 			break;
193 		}
194 
195 
196 		if (err < 0) {
197 			printk(KERN_ERR "CPA %d failed %d\n", i, err);
198 			failed++;
199 		}
200 
201 		pte = lookup_address(addr[i], &level);
202 		if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
203 			printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
204 				pte ? (u64)pte_val(*pte) : 0ULL);
205 			failed++;
206 		}
207 		if (level != PG_LEVEL_4K) {
208 			printk(KERN_ERR "CPA %lx: unexpected level %d\n",
209 				addr[i], level);
210 			failed++;
211 		}
212 
213 	}
214 	vfree(bm);
215 
216 	failed += print_split(&sb);
217 
218 	for (i = 0; i < NTEST; i++) {
219 		if (!addr[i])
220 			continue;
221 		pte = lookup_address(addr[i], &level);
222 		if (!pte) {
223 			printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
224 			failed++;
225 			continue;
226 		}
227 		err = change_page_attr_clear(&addr[i], len[i], PAGE_CPA_TEST, 0);
228 		if (err < 0) {
229 			printk(KERN_ERR "CPA reverting failed: %d\n", err);
230 			failed++;
231 		}
232 		pte = lookup_address(addr[i], &level);
233 		if (!pte || pte_testbit(*pte)) {
234 			printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
235 				addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
236 			failed++;
237 		}
238 
239 	}
240 
241 	failed += print_split(&sc);
242 
243 	if (failed) {
244 		WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
245 		return -EINVAL;
246 	} else {
247 		if (print)
248 			printk(KERN_INFO "ok.\n");
249 	}
250 
251 	return 0;
252 }
253 
254 static int do_pageattr_test(void *__unused)
255 {
256 	while (!kthread_should_stop()) {
257 		schedule_timeout_interruptible(HZ*30);
258 		if (pageattr_test() < 0)
259 			break;
260 		if (print)
261 			print--;
262 	}
263 	return 0;
264 }
265 
266 static int start_pageattr_test(void)
267 {
268 	struct task_struct *p;
269 
270 	p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
271 	if (!IS_ERR(p))
272 		wake_up_process(p);
273 	else
274 		WARN_ON(1);
275 
276 	return 0;
277 }
278 device_initcall(start_pageattr_test);
279