1 #include <linux/kernel.h>
2 #include <linux/mm.h>
3 #include <linux/slab.h>
4 #include <linux/uaccess.h>
5 #include <linux/ktime.h>
6 #include <linux/debugfs.h>
7 #include "gup_test.h"
8 
put_back_pages(unsigned int cmd,struct page ** pages,unsigned long nr_pages,unsigned int gup_test_flags)9 static void put_back_pages(unsigned int cmd, struct page **pages,
10 			   unsigned long nr_pages, unsigned int gup_test_flags)
11 {
12 	unsigned long i;
13 
14 	switch (cmd) {
15 	case GUP_FAST_BENCHMARK:
16 	case GUP_BASIC_TEST:
17 		for (i = 0; i < nr_pages; i++)
18 			put_page(pages[i]);
19 		break;
20 
21 	case PIN_FAST_BENCHMARK:
22 	case PIN_BASIC_TEST:
23 	case PIN_LONGTERM_BENCHMARK:
24 		unpin_user_pages(pages, nr_pages);
25 		break;
26 	case DUMP_USER_PAGES_TEST:
27 		if (gup_test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN) {
28 			unpin_user_pages(pages, nr_pages);
29 		} else {
30 			for (i = 0; i < nr_pages; i++)
31 				put_page(pages[i]);
32 
33 		}
34 		break;
35 	}
36 }
37 
verify_dma_pinned(unsigned int cmd,struct page ** pages,unsigned long nr_pages)38 static void verify_dma_pinned(unsigned int cmd, struct page **pages,
39 			      unsigned long nr_pages)
40 {
41 	unsigned long i;
42 	struct page *page;
43 
44 	switch (cmd) {
45 	case PIN_FAST_BENCHMARK:
46 	case PIN_BASIC_TEST:
47 	case PIN_LONGTERM_BENCHMARK:
48 		for (i = 0; i < nr_pages; i++) {
49 			page = pages[i];
50 			if (WARN(!page_maybe_dma_pinned(page),
51 				 "pages[%lu] is NOT dma-pinned\n", i)) {
52 
53 				dump_page(page, "gup_test failure");
54 				break;
55 			} else if (cmd == PIN_LONGTERM_BENCHMARK &&
56 				WARN(!is_pinnable_page(page),
57 				     "pages[%lu] is NOT pinnable but pinned\n",
58 				     i)) {
59 				dump_page(page, "gup_test failure");
60 				break;
61 			}
62 		}
63 		break;
64 	}
65 }
66 
dump_pages_test(struct gup_test * gup,struct page ** pages,unsigned long nr_pages)67 static void dump_pages_test(struct gup_test *gup, struct page **pages,
68 			    unsigned long nr_pages)
69 {
70 	unsigned int index_to_dump;
71 	unsigned int i;
72 
73 	/*
74 	 * Zero out any user-supplied page index that is out of range. Remember:
75 	 * .which_pages[] contains a 1-based set of page indices.
76 	 */
77 	for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) {
78 		if (gup->which_pages[i] > nr_pages) {
79 			pr_warn("ZEROING due to out of range: .which_pages[%u]: %u\n",
80 				i, gup->which_pages[i]);
81 			gup->which_pages[i] = 0;
82 		}
83 	}
84 
85 	for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) {
86 		index_to_dump = gup->which_pages[i];
87 
88 		if (index_to_dump) {
89 			index_to_dump--; // Decode from 1-based, to 0-based
90 			pr_info("---- page #%u, starting from user virt addr: 0x%llx\n",
91 				index_to_dump, gup->addr);
92 			dump_page(pages[index_to_dump],
93 				  "gup_test: dump_pages() test");
94 		}
95 	}
96 }
97 
__gup_test_ioctl(unsigned int cmd,struct gup_test * gup)98 static int __gup_test_ioctl(unsigned int cmd,
99 		struct gup_test *gup)
100 {
101 	ktime_t start_time, end_time;
102 	unsigned long i, nr_pages, addr, next;
103 	long nr;
104 	struct page **pages;
105 	int ret = 0;
106 	bool needs_mmap_lock =
107 		cmd != GUP_FAST_BENCHMARK && cmd != PIN_FAST_BENCHMARK;
108 
109 	if (gup->size > ULONG_MAX)
110 		return -EINVAL;
111 
112 	nr_pages = gup->size / PAGE_SIZE;
113 	pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
114 	if (!pages)
115 		return -ENOMEM;
116 
117 	if (needs_mmap_lock && mmap_read_lock_killable(current->mm)) {
118 		ret = -EINTR;
119 		goto free_pages;
120 	}
121 
122 	i = 0;
123 	nr = gup->nr_pages_per_call;
124 	start_time = ktime_get();
125 	for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
126 		if (nr != gup->nr_pages_per_call)
127 			break;
128 
129 		next = addr + nr * PAGE_SIZE;
130 		if (next > gup->addr + gup->size) {
131 			next = gup->addr + gup->size;
132 			nr = (next - addr) / PAGE_SIZE;
133 		}
134 
135 		switch (cmd) {
136 		case GUP_FAST_BENCHMARK:
137 			nr = get_user_pages_fast(addr, nr, gup->gup_flags,
138 						 pages + i);
139 			break;
140 		case GUP_BASIC_TEST:
141 			nr = get_user_pages(addr, nr, gup->gup_flags, pages + i,
142 					    NULL);
143 			break;
144 		case PIN_FAST_BENCHMARK:
145 			nr = pin_user_pages_fast(addr, nr, gup->gup_flags,
146 						 pages + i);
147 			break;
148 		case PIN_BASIC_TEST:
149 			nr = pin_user_pages(addr, nr, gup->gup_flags, pages + i,
150 					    NULL);
151 			break;
152 		case PIN_LONGTERM_BENCHMARK:
153 			nr = pin_user_pages(addr, nr,
154 					    gup->gup_flags | FOLL_LONGTERM,
155 					    pages + i, NULL);
156 			break;
157 		case DUMP_USER_PAGES_TEST:
158 			if (gup->test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)
159 				nr = pin_user_pages(addr, nr, gup->gup_flags,
160 						    pages + i, NULL);
161 			else
162 				nr = get_user_pages(addr, nr, gup->gup_flags,
163 						    pages + i, NULL);
164 			break;
165 		default:
166 			ret = -EINVAL;
167 			goto unlock;
168 		}
169 
170 		if (nr <= 0)
171 			break;
172 		i += nr;
173 	}
174 	end_time = ktime_get();
175 
176 	/* Shifting the meaning of nr_pages: now it is actual number pinned: */
177 	nr_pages = i;
178 
179 	gup->get_delta_usec = ktime_us_delta(end_time, start_time);
180 	gup->size = addr - gup->addr;
181 
182 	/*
183 	 * Take an un-benchmark-timed moment to verify DMA pinned
184 	 * state: print a warning if any non-dma-pinned pages are found:
185 	 */
186 	verify_dma_pinned(cmd, pages, nr_pages);
187 
188 	if (cmd == DUMP_USER_PAGES_TEST)
189 		dump_pages_test(gup, pages, nr_pages);
190 
191 	start_time = ktime_get();
192 
193 	put_back_pages(cmd, pages, nr_pages, gup->test_flags);
194 
195 	end_time = ktime_get();
196 	gup->put_delta_usec = ktime_us_delta(end_time, start_time);
197 
198 unlock:
199 	if (needs_mmap_lock)
200 		mmap_read_unlock(current->mm);
201 free_pages:
202 	kvfree(pages);
203 	return ret;
204 }
205 
gup_test_ioctl(struct file * filep,unsigned int cmd,unsigned long arg)206 static long gup_test_ioctl(struct file *filep, unsigned int cmd,
207 		unsigned long arg)
208 {
209 	struct gup_test gup;
210 	int ret;
211 
212 	switch (cmd) {
213 	case GUP_FAST_BENCHMARK:
214 	case PIN_FAST_BENCHMARK:
215 	case PIN_LONGTERM_BENCHMARK:
216 	case GUP_BASIC_TEST:
217 	case PIN_BASIC_TEST:
218 	case DUMP_USER_PAGES_TEST:
219 		break;
220 	default:
221 		return -EINVAL;
222 	}
223 
224 	if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
225 		return -EFAULT;
226 
227 	ret = __gup_test_ioctl(cmd, &gup);
228 	if (ret)
229 		return ret;
230 
231 	if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
232 		return -EFAULT;
233 
234 	return 0;
235 }
236 
237 static const struct file_operations gup_test_fops = {
238 	.open = nonseekable_open,
239 	.unlocked_ioctl = gup_test_ioctl,
240 };
241 
gup_test_init(void)242 static int __init gup_test_init(void)
243 {
244 	debugfs_create_file_unsafe("gup_test", 0600, NULL, NULL,
245 				   &gup_test_fops);
246 
247 	return 0;
248 }
249 
250 late_initcall(gup_test_init);
251