1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2023 Ventana Micro Systems Inc.
4 *
5 * Run with 'taskset -c <cpu-list> cbo' to only execute hwprobe on a
6 * subset of cpus, as well as only executing the tests on those cpus.
7 */
8 #define _GNU_SOURCE
9 #include <stdbool.h>
10 #include <stdint.h>
11 #include <string.h>
12 #include <sched.h>
13 #include <signal.h>
14 #include <assert.h>
15 #include <linux/compiler.h>
16 #include <linux/kernel.h>
17 #include <asm/ucontext.h>
18
19 #include "hwprobe.h"
20 #include "../../kselftest.h"
21
22 #define MK_CBO(fn) le32_bswap((uint32_t)(fn) << 20 | 10 << 15 | 2 << 12 | 0 << 7 | 15)
23
24 static char mem[4096] __aligned(4096) = { [0 ... 4095] = 0xa5 };
25
26 static bool illegal_insn;
27
sigill_handler(int sig,siginfo_t * info,void * context)28 static void sigill_handler(int sig, siginfo_t *info, void *context)
29 {
30 unsigned long *regs = (unsigned long *)&((ucontext_t *)context)->uc_mcontext;
31 uint32_t insn = *(uint32_t *)regs[0];
32
33 assert(insn == MK_CBO(regs[11]));
34
35 illegal_insn = true;
36 regs[0] += 4;
37 }
38
39 #define cbo_insn(base, fn) \
40 ({ \
41 asm volatile( \
42 "mv a0, %0\n" \
43 "li a1, %1\n" \
44 ".4byte %2\n" \
45 : : "r" (base), "i" (fn), "i" (MK_CBO(fn)) : "a0", "a1", "memory"); \
46 })
47
cbo_inval(char * base)48 static void cbo_inval(char *base) { cbo_insn(base, 0); }
cbo_clean(char * base)49 static void cbo_clean(char *base) { cbo_insn(base, 1); }
cbo_flush(char * base)50 static void cbo_flush(char *base) { cbo_insn(base, 2); }
cbo_zero(char * base)51 static void cbo_zero(char *base) { cbo_insn(base, 4); }
52
test_no_zicbom(void * arg)53 static void test_no_zicbom(void *arg)
54 {
55 ksft_print_msg("Testing Zicbom instructions remain privileged\n");
56
57 illegal_insn = false;
58 cbo_clean(&mem[0]);
59 ksft_test_result(illegal_insn, "No cbo.clean\n");
60
61 illegal_insn = false;
62 cbo_flush(&mem[0]);
63 ksft_test_result(illegal_insn, "No cbo.flush\n");
64
65 illegal_insn = false;
66 cbo_inval(&mem[0]);
67 ksft_test_result(illegal_insn, "No cbo.inval\n");
68 }
69
test_no_zicboz(void * arg)70 static void test_no_zicboz(void *arg)
71 {
72 ksft_print_msg("No Zicboz, testing cbo.zero remains privileged\n");
73
74 illegal_insn = false;
75 cbo_zero(&mem[0]);
76 ksft_test_result(illegal_insn, "No cbo.zero\n");
77 }
78
is_power_of_2(__u64 n)79 static bool is_power_of_2(__u64 n)
80 {
81 return n != 0 && (n & (n - 1)) == 0;
82 }
83
test_zicboz(void * arg)84 static void test_zicboz(void *arg)
85 {
86 struct riscv_hwprobe pair = {
87 .key = RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE,
88 };
89 cpu_set_t *cpus = (cpu_set_t *)arg;
90 __u64 block_size;
91 int i, j;
92 long rc;
93
94 rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)cpus, 0);
95 block_size = pair.value;
96 ksft_test_result(rc == 0 && pair.key == RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE &&
97 is_power_of_2(block_size), "Zicboz block size\n");
98 ksft_print_msg("Zicboz block size: %llu\n", block_size);
99
100 illegal_insn = false;
101 cbo_zero(&mem[block_size]);
102 ksft_test_result(!illegal_insn, "cbo.zero\n");
103
104 if (illegal_insn || !is_power_of_2(block_size)) {
105 ksft_test_result_skip("cbo.zero check\n");
106 return;
107 }
108
109 assert(block_size <= 1024);
110
111 for (i = 0; i < 4096 / block_size; ++i) {
112 if (i % 2)
113 cbo_zero(&mem[i * block_size]);
114 }
115
116 for (i = 0; i < 4096 / block_size; ++i) {
117 char expected = i % 2 ? 0x0 : 0xa5;
118
119 for (j = 0; j < block_size; ++j) {
120 if (mem[i * block_size + j] != expected) {
121 ksft_test_result_fail("cbo.zero check\n");
122 ksft_print_msg("cbo.zero check: mem[%llu] != 0x%x\n",
123 i * block_size + j, expected);
124 return;
125 }
126 }
127 }
128
129 ksft_test_result_pass("cbo.zero check\n");
130 }
131
check_no_zicboz_cpus(cpu_set_t * cpus)132 static void check_no_zicboz_cpus(cpu_set_t *cpus)
133 {
134 struct riscv_hwprobe pair = {
135 .key = RISCV_HWPROBE_KEY_IMA_EXT_0,
136 };
137 cpu_set_t one_cpu;
138 int i = 0, c = 0;
139 long rc;
140
141 while (i++ < CPU_COUNT(cpus)) {
142 while (!CPU_ISSET(c, cpus))
143 ++c;
144
145 CPU_ZERO(&one_cpu);
146 CPU_SET(c, &one_cpu);
147
148 rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)&one_cpu, 0);
149 assert(rc == 0 && pair.key == RISCV_HWPROBE_KEY_IMA_EXT_0);
150
151 if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ)
152 ksft_exit_fail_msg("Zicboz is only present on a subset of harts.\n"
153 "Use taskset to select a set of harts where Zicboz\n"
154 "presence (present or not) is consistent for each hart\n");
155 ++c;
156 }
157 }
158
159 enum {
160 TEST_ZICBOZ,
161 TEST_NO_ZICBOZ,
162 TEST_NO_ZICBOM,
163 };
164
165 static struct test_info {
166 bool enabled;
167 unsigned int nr_tests;
168 void (*test_fn)(void *arg);
169 } tests[] = {
170 [TEST_ZICBOZ] = { .nr_tests = 3, test_zicboz },
171 [TEST_NO_ZICBOZ] = { .nr_tests = 1, test_no_zicboz },
172 [TEST_NO_ZICBOM] = { .nr_tests = 3, test_no_zicbom },
173 };
174
main(int argc,char ** argv)175 int main(int argc, char **argv)
176 {
177 struct sigaction act = {
178 .sa_sigaction = &sigill_handler,
179 .sa_flags = SA_SIGINFO,
180 };
181 struct riscv_hwprobe pair;
182 unsigned int plan = 0;
183 cpu_set_t cpus;
184 long rc;
185 int i;
186
187 if (argc > 1 && !strcmp(argv[1], "--sigill")) {
188 rc = sigaction(SIGILL, &act, NULL);
189 assert(rc == 0);
190 tests[TEST_NO_ZICBOZ].enabled = true;
191 tests[TEST_NO_ZICBOM].enabled = true;
192 }
193
194 rc = sched_getaffinity(0, sizeof(cpu_set_t), &cpus);
195 assert(rc == 0);
196
197 ksft_print_header();
198
199 pair.key = RISCV_HWPROBE_KEY_IMA_EXT_0;
200 rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)&cpus, 0);
201 if (rc < 0)
202 ksft_exit_fail_msg("hwprobe() failed with %ld\n", rc);
203 assert(rc == 0 && pair.key == RISCV_HWPROBE_KEY_IMA_EXT_0);
204
205 if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ) {
206 tests[TEST_ZICBOZ].enabled = true;
207 tests[TEST_NO_ZICBOZ].enabled = false;
208 } else {
209 check_no_zicboz_cpus(&cpus);
210 }
211
212 for (i = 0; i < ARRAY_SIZE(tests); ++i)
213 plan += tests[i].enabled ? tests[i].nr_tests : 0;
214
215 if (plan == 0)
216 ksft_print_msg("No tests enabled.\n");
217 else
218 ksft_set_plan(plan);
219
220 for (i = 0; i < ARRAY_SIZE(tests); ++i) {
221 if (tests[i].enabled)
222 tests[i].test_fn(&cpus);
223 }
224
225 ksft_finished();
226 }
227