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/init.h>
 12#include <linux/mm.h>
 13
 14#include <asm/cacheflush.h>
 15#include <asm/pgtable.h>
 16#include <asm/kdebug.h>
 17
 18/*
 19 * Only print the results of the first pass:
 20 */
 21static __read_mostly int print = 1;
 22
 23enum {
 24	NTEST			= 400,
 25#ifdef CONFIG_X86_64
 26	LPS			= (1 << PMD_SHIFT),
 27#elif defined(CONFIG_X86_PAE)
 28	LPS			= (1 << PMD_SHIFT),
 29#else
 30	LPS			= (1 << 22),
 31#endif
 32	GPS			= (1<<30)
 33};
 34
 35#define PAGE_CPA_TEST	__pgprot(_PAGE_CPA_TEST)
 36
 37static int pte_testbit(pte_t pte)
 38{
 39	return pte_flags(pte) & _PAGE_UNUSED1;
 40}
 41
 42struct split_state {
 43	long lpg, gpg, spg, exec;
 44	long min_exec, max_exec;
 45};
 46
 47static int print_split(struct split_state *s)
 48{
 49	long i, expected, missed = 0;
 50	int err = 0;
 51
 52	s->lpg = s->gpg = s->spg = s->exec = 0;
 53	s->min_exec = ~0UL;
 54	s->max_exec = 0;
 55	for (i = 0; i < max_pfn_mapped; ) {
 56		unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
 57		unsigned int level;
 58		pte_t *pte;
 59
 60		pte = lookup_address(addr, &level);
 61		if (!pte) {
 62			missed++;
 63			i++;
 64			continue;
 65		}
 66
 67		if (level == PG_LEVEL_1G && sizeof(long) == 8) {
 68			s->gpg++;
 69			i += GPS/PAGE_SIZE;
 70		} else if (level == PG_LEVEL_2M) {
 71			if (!(pte_val(*pte) & _PAGE_PSE)) {
 72				printk(KERN_ERR
 73					"%lx level %d but not PSE %Lx\n",
 74					addr, level, (u64)pte_val(*pte));
 75				err = 1;
 76			}
 77			s->lpg++;
 78			i += LPS/PAGE_SIZE;
 79		} else {
 80			s->spg++;
 81			i++;
 82		}
 83		if (!(pte_val(*pte) & _PAGE_NX)) {
 84			s->exec++;
 85			if (addr < s->min_exec)
 86				s->min_exec = addr;
 87			if (addr > s->max_exec)
 88				s->max_exec = addr;
 89		}
 90	}
 91	if (print) {
 92		printk(KERN_INFO
 93			" 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
 94			s->spg, s->lpg, s->gpg, s->exec,
 95			s->min_exec != ~0UL ? s->min_exec : 0,
 96			s->max_exec, missed);
 97	}
 98
 99	expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
100	if (expected != i) {
101		printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
102			max_pfn_mapped, expected);
103		return 1;
104	}
105	return err;
106}
107
108static unsigned long addr[NTEST];
109static unsigned int len[NTEST];
110
111/* Change the global bit on random pages in the direct mapping */
112static int pageattr_test(void)
113{
114	struct split_state sa, sb, sc;
115	unsigned long *bm;
116	pte_t *pte, pte0;
117	int failed = 0;
118	unsigned int level;
119	int i, k;
120	int err;
121	unsigned long test_addr;
122
123	if (print)
124		printk(KERN_INFO "CPA self-test:\n");
125
126	bm = vzalloc((max_pfn_mapped + 7) / 8);
127	if (!bm) {
128		printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
129		return -ENOMEM;
130	}
131
132	failed += print_split(&sa);
133	srandom32(100);
134
135	for (i = 0; i < NTEST; i++) {
136		unsigned long pfn = random32() % max_pfn_mapped;
137
138		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
139		len[i] = random32() % 100;
140		len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
141
142		if (len[i] == 0)
143			len[i] = 1;
144
145		pte = NULL;
146		pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
147
148		for (k = 0; k < len[i]; k++) {
149			pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
150			if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
151			    !(pte_val(*pte) & _PAGE_PRESENT)) {
152				addr[i] = 0;
153				break;
154			}
155			if (k == 0) {
156				pte0 = *pte;
157			} else {
158				if (pgprot_val(pte_pgprot(*pte)) !=
159					pgprot_val(pte_pgprot(pte0))) {
160					len[i] = k;
161					break;
162				}
163			}
164			if (test_bit(pfn + k, bm)) {
165				len[i] = k;
166				break;
167			}
168			__set_bit(pfn + k, bm);
169		}
170		if (!addr[i] || !pte || !k) {
171			addr[i] = 0;
172			continue;
173		}
174
175		test_addr = addr[i];
176		err = change_page_attr_set(&test_addr, len[i], PAGE_CPA_TEST, 0);
177		if (err < 0) {
178			printk(KERN_ERR "CPA %d failed %d\n", i, err);
179			failed++;
180		}
181
182		pte = lookup_address(addr[i], &level);
183		if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
184			printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
185				pte ? (u64)pte_val(*pte) : 0ULL);
186			failed++;
187		}
188		if (level != PG_LEVEL_4K) {
189			printk(KERN_ERR "CPA %lx: unexpected level %d\n",
190				addr[i], level);
191			failed++;
192		}
193
194	}
195	vfree(bm);
196
197	failed += print_split(&sb);
198
199	for (i = 0; i < NTEST; i++) {
200		if (!addr[i])
201			continue;
202		pte = lookup_address(addr[i], &level);
203		if (!pte) {
204			printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
205			failed++;
206			continue;
207		}
208		test_addr = addr[i];
209		err = change_page_attr_clear(&test_addr, len[i], PAGE_CPA_TEST, 0);
210		if (err < 0) {
211			printk(KERN_ERR "CPA reverting failed: %d\n", err);
212			failed++;
213		}
214		pte = lookup_address(addr[i], &level);
215		if (!pte || pte_testbit(*pte)) {
216			printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
217				addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
218			failed++;
219		}
220
221	}
222
223	failed += print_split(&sc);
224
225	if (failed) {
226		WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
227		return -EINVAL;
228	} else {
229		if (print)
230			printk(KERN_INFO "ok.\n");
231	}
232
233	return 0;
234}
235
236static int do_pageattr_test(void *__unused)
237{
238	while (!kthread_should_stop()) {
239		schedule_timeout_interruptible(HZ*30);
240		if (pageattr_test() < 0)
241			break;
242		if (print)
243			print--;
244	}
245	return 0;
246}
247
248static int start_pageattr_test(void)
249{
250	struct task_struct *p;
251
252	p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
253	if (!IS_ERR(p))
254		wake_up_process(p);
255	else
256		WARN_ON(1);
257
258	return 0;
259}
260
261module_init(start_pageattr_test);