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 */
20 static __read_mostly int print = 1;
21
22 enum {
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
pte_testbit(pte_t pte)36 static int pte_testbit(pte_t pte)
37 {
38 return pte_flags(pte) & _PAGE_SOFTW1;
39 }
40
41 struct split_state {
42 long lpg, gpg, spg, exec;
43 long min_exec, max_exec;
44 };
45
print_split(struct split_state * s)46 static 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
107 static unsigned long addr[NTEST];
108 static unsigned int len[NTEST];
109
110 /* Change the global bit on random pages in the direct mapping */
pageattr_test(void)111 static 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
do_pageattr_test(void * __unused)234 static 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
start_pageattr_test(void)246 static 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
259 module_init(start_pageattr_test);
260