1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun
3*4882a593Smuzhiyun #define pr_fmt(fmt) "kcsan: " fmt
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun #include <linux/init.h>
6*4882a593Smuzhiyun #include <linux/kernel.h>
7*4882a593Smuzhiyun #include <linux/printk.h>
8*4882a593Smuzhiyun #include <linux/random.h>
9*4882a593Smuzhiyun #include <linux/types.h>
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include "encoding.h"
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #define ITERS_PER_TEST 2000
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun /* Test requirements. */
test_requires(void)16*4882a593Smuzhiyun static bool test_requires(void)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun /* random should be initialized for the below tests */
19*4882a593Smuzhiyun return prandom_u32() + prandom_u32() != 0;
20*4882a593Smuzhiyun }
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun /*
23*4882a593Smuzhiyun * Test watchpoint encode and decode: check that encoding some access's info,
24*4882a593Smuzhiyun * and then subsequent decode preserves the access's info.
25*4882a593Smuzhiyun */
test_encode_decode(void)26*4882a593Smuzhiyun static bool test_encode_decode(void)
27*4882a593Smuzhiyun {
28*4882a593Smuzhiyun int i;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun for (i = 0; i < ITERS_PER_TEST; ++i) {
31*4882a593Smuzhiyun size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1;
32*4882a593Smuzhiyun bool is_write = !!prandom_u32_max(2);
33*4882a593Smuzhiyun unsigned long addr;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun prandom_bytes(&addr, sizeof(addr));
36*4882a593Smuzhiyun if (WARN_ON(!check_encodable(addr, size)))
37*4882a593Smuzhiyun return false;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun /* Encode and decode */
40*4882a593Smuzhiyun {
41*4882a593Smuzhiyun const long encoded_watchpoint =
42*4882a593Smuzhiyun encode_watchpoint(addr, size, is_write);
43*4882a593Smuzhiyun unsigned long verif_masked_addr;
44*4882a593Smuzhiyun size_t verif_size;
45*4882a593Smuzhiyun bool verif_is_write;
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun /* Check special watchpoints */
48*4882a593Smuzhiyun if (WARN_ON(decode_watchpoint(
49*4882a593Smuzhiyun INVALID_WATCHPOINT, &verif_masked_addr,
50*4882a593Smuzhiyun &verif_size, &verif_is_write)))
51*4882a593Smuzhiyun return false;
52*4882a593Smuzhiyun if (WARN_ON(decode_watchpoint(
53*4882a593Smuzhiyun CONSUMED_WATCHPOINT, &verif_masked_addr,
54*4882a593Smuzhiyun &verif_size, &verif_is_write)))
55*4882a593Smuzhiyun return false;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun /* Check decoding watchpoint returns same data */
58*4882a593Smuzhiyun if (WARN_ON(!decode_watchpoint(
59*4882a593Smuzhiyun encoded_watchpoint, &verif_masked_addr,
60*4882a593Smuzhiyun &verif_size, &verif_is_write)))
61*4882a593Smuzhiyun return false;
62*4882a593Smuzhiyun if (WARN_ON(verif_masked_addr !=
63*4882a593Smuzhiyun (addr & WATCHPOINT_ADDR_MASK)))
64*4882a593Smuzhiyun goto fail;
65*4882a593Smuzhiyun if (WARN_ON(verif_size != size))
66*4882a593Smuzhiyun goto fail;
67*4882a593Smuzhiyun if (WARN_ON(is_write != verif_is_write))
68*4882a593Smuzhiyun goto fail;
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun continue;
71*4882a593Smuzhiyun fail:
72*4882a593Smuzhiyun pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n",
73*4882a593Smuzhiyun __func__, is_write ? "write" : "read", size,
74*4882a593Smuzhiyun addr, encoded_watchpoint,
75*4882a593Smuzhiyun verif_is_write ? "write" : "read", verif_size,
76*4882a593Smuzhiyun verif_masked_addr);
77*4882a593Smuzhiyun return false;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun return true;
82*4882a593Smuzhiyun }
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun /* Test access matching function. */
test_matching_access(void)85*4882a593Smuzhiyun static bool test_matching_access(void)
86*4882a593Smuzhiyun {
87*4882a593Smuzhiyun if (WARN_ON(!matching_access(10, 1, 10, 1)))
88*4882a593Smuzhiyun return false;
89*4882a593Smuzhiyun if (WARN_ON(!matching_access(10, 2, 11, 1)))
90*4882a593Smuzhiyun return false;
91*4882a593Smuzhiyun if (WARN_ON(!matching_access(10, 1, 9, 2)))
92*4882a593Smuzhiyun return false;
93*4882a593Smuzhiyun if (WARN_ON(matching_access(10, 1, 11, 1)))
94*4882a593Smuzhiyun return false;
95*4882a593Smuzhiyun if (WARN_ON(matching_access(9, 1, 10, 1)))
96*4882a593Smuzhiyun return false;
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun /*
99*4882a593Smuzhiyun * An access of size 0 could match another access, as demonstrated here.
100*4882a593Smuzhiyun * Rather than add more comparisons to 'matching_access()', which would
101*4882a593Smuzhiyun * end up in the fast-path for *all* checks, check_access() simply
102*4882a593Smuzhiyun * returns for all accesses of size 0.
103*4882a593Smuzhiyun */
104*4882a593Smuzhiyun if (WARN_ON(!matching_access(8, 8, 12, 0)))
105*4882a593Smuzhiyun return false;
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun return true;
108*4882a593Smuzhiyun }
109*4882a593Smuzhiyun
kcsan_selftest(void)110*4882a593Smuzhiyun static int __init kcsan_selftest(void)
111*4882a593Smuzhiyun {
112*4882a593Smuzhiyun int passed = 0;
113*4882a593Smuzhiyun int total = 0;
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun #define RUN_TEST(do_test) \
116*4882a593Smuzhiyun do { \
117*4882a593Smuzhiyun ++total; \
118*4882a593Smuzhiyun if (do_test()) \
119*4882a593Smuzhiyun ++passed; \
120*4882a593Smuzhiyun else \
121*4882a593Smuzhiyun pr_err("selftest: " #do_test " failed"); \
122*4882a593Smuzhiyun } while (0)
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun RUN_TEST(test_requires);
125*4882a593Smuzhiyun RUN_TEST(test_encode_decode);
126*4882a593Smuzhiyun RUN_TEST(test_matching_access);
127*4882a593Smuzhiyun
128*4882a593Smuzhiyun pr_info("selftest: %d/%d tests passed\n", passed, total);
129*4882a593Smuzhiyun if (passed != total)
130*4882a593Smuzhiyun panic("selftests failed");
131*4882a593Smuzhiyun return 0;
132*4882a593Smuzhiyun }
133*4882a593Smuzhiyun postcore_initcall(kcsan_selftest);
134