1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2019 ARM Limited */
3 
4 #include <stdio.h>
5 #include <stdlib.h>
6 #include <signal.h>
7 #include <string.h>
8 #include <unistd.h>
9 #include <assert.h>
10 #include <sys/auxv.h>
11 #include <linux/auxvec.h>
12 #include <ucontext.h>
13 
14 #include <asm/unistd.h>
15 
16 #include <kselftest.h>
17 
18 #include "test_signals.h"
19 #include "test_signals_utils.h"
20 #include "testcases/testcases.h"
21 
22 
23 extern struct tdescr *current;
24 
25 static int sig_copyctx = SIGTRAP;
26 
27 static char const *const feats_names[FMAX_END] = {
28 	" SSBS ",
29 	" SVE ",
30 };
31 
32 #define MAX_FEATS_SZ	128
33 static char feats_string[MAX_FEATS_SZ];
34 
35 static inline char *feats_to_string(unsigned long feats)
36 {
37 	size_t flen = MAX_FEATS_SZ - 1;
38 
39 	for (int i = 0; i < FMAX_END; i++) {
40 		if (feats & (1UL << i)) {
41 			size_t tlen = strlen(feats_names[i]);
42 
43 			assert(flen > tlen);
44 			flen -= tlen;
45 			strncat(feats_string, feats_names[i], flen);
46 		}
47 	}
48 
49 	return feats_string;
50 }
51 
52 static void unblock_signal(int signum)
53 {
54 	sigset_t sset;
55 
56 	sigemptyset(&sset);
57 	sigaddset(&sset, signum);
58 	sigprocmask(SIG_UNBLOCK, &sset, NULL);
59 }
60 
61 static void default_result(struct tdescr *td, bool force_exit)
62 {
63 	if (td->result == KSFT_SKIP) {
64 		fprintf(stderr, "==>> completed. SKIP.\n");
65 	} else if (td->pass) {
66 		fprintf(stderr, "==>> completed. PASS(1)\n");
67 		td->result = KSFT_PASS;
68 	} else {
69 		fprintf(stdout, "==>> completed. FAIL(0)\n");
70 		td->result = KSFT_FAIL;
71 	}
72 
73 	if (force_exit)
74 		exit(td->result);
75 }
76 
77 /*
78  * The following handle_signal_* helpers are used by main default_handler
79  * and are meant to return true when signal is handled successfully:
80  * when false is returned instead, it means that the signal was somehow
81  * unexpected in that context and it was NOT handled; default_handler will
82  * take care of such unexpected situations.
83  */
84 
85 static bool handle_signal_unsupported(struct tdescr *td,
86 				      siginfo_t *si, void *uc)
87 {
88 	if (feats_ok(td))
89 		return false;
90 
91 	/* Mangling PC to avoid loops on original SIGILL */
92 	((ucontext_t *)uc)->uc_mcontext.pc += 4;
93 
94 	if (!td->initialized) {
95 		fprintf(stderr,
96 			"Got SIG_UNSUPP @test_init. Ignore.\n");
97 	} else {
98 		fprintf(stderr,
99 			"-- RX SIG_UNSUPP on unsupported feat...OK\n");
100 		td->pass = 1;
101 		default_result(current, 1);
102 	}
103 
104 	return true;
105 }
106 
107 static bool handle_signal_trigger(struct tdescr *td,
108 				  siginfo_t *si, void *uc)
109 {
110 	td->triggered = 1;
111 	/* ->run was asserted NON-NULL in test_setup() already */
112 	td->run(td, si, uc);
113 
114 	return true;
115 }
116 
117 static bool handle_signal_ok(struct tdescr *td,
118 			     siginfo_t *si, void *uc)
119 {
120 	/*
121 	 * it's a bug in the test code when this assert fail:
122 	 * if sig_trig was defined, it must have been used before getting here.
123 	 */
124 	assert(!td->sig_trig || td->triggered);
125 	fprintf(stderr,
126 		"SIG_OK -- SP:0x%llX  si_addr@:%p  si_code:%d  token@:%p  offset:%ld\n",
127 		((ucontext_t *)uc)->uc_mcontext.sp,
128 		si->si_addr, si->si_code, td->token, td->token - si->si_addr);
129 	/*
130 	 * fake_sigreturn tests, which have sanity_enabled=1, set, at the very
131 	 * last time, the token field to the SP address used to place the fake
132 	 * sigframe: so token==0 means we never made it to the end,
133 	 * segfaulting well-before, and the test is possibly broken.
134 	 */
135 	if (!td->sanity_disabled && !td->token) {
136 		fprintf(stdout,
137 			"current->token ZEROED...test is probably broken!\n");
138 		abort();
139 	}
140 	/*
141 	 * Trying to narrow down the SEGV to the ones generated by Kernel itself
142 	 * via arm64_notify_segfault(). This is a best-effort check anyway, and
143 	 * the si_code check may need to change if this aspect of the kernel
144 	 * ABI changes.
145 	 */
146 	if (td->sig_ok == SIGSEGV && si->si_code != SEGV_ACCERR) {
147 		fprintf(stdout,
148 			"si_code != SEGV_ACCERR...test is probably broken!\n");
149 		abort();
150 	}
151 	td->pass = 1;
152 	/*
153 	 * Some tests can lead to SEGV loops: in such a case we want to
154 	 * terminate immediately exiting straight away; some others are not
155 	 * supposed to outlive the signal handler code, due to the content of
156 	 * the fake sigframe which caused the signal itself.
157 	 */
158 	default_result(current, 1);
159 
160 	return true;
161 }
162 
163 static bool handle_signal_copyctx(struct tdescr *td,
164 				  siginfo_t *si, void *uc)
165 {
166 	/* Mangling PC to avoid loops on original BRK instr */
167 	((ucontext_t *)uc)->uc_mcontext.pc += 4;
168 	memcpy(td->live_uc, uc, td->live_sz);
169 	ASSERT_GOOD_CONTEXT(td->live_uc);
170 	td->live_uc_valid = 1;
171 	fprintf(stderr,
172 		"GOOD CONTEXT grabbed from sig_copyctx handler\n");
173 
174 	return true;
175 }
176 
177 static void default_handler(int signum, siginfo_t *si, void *uc)
178 {
179 	if (current->sig_unsupp && signum == current->sig_unsupp &&
180 	    handle_signal_unsupported(current, si, uc)) {
181 		fprintf(stderr, "Handled SIG_UNSUPP\n");
182 	} else if (current->sig_trig && signum == current->sig_trig &&
183 		   handle_signal_trigger(current, si, uc)) {
184 		fprintf(stderr, "Handled SIG_TRIG\n");
185 	} else if (current->sig_ok && signum == current->sig_ok &&
186 		   handle_signal_ok(current, si, uc)) {
187 		fprintf(stderr, "Handled SIG_OK\n");
188 	} else if (signum == sig_copyctx && current->live_uc &&
189 		   handle_signal_copyctx(current, si, uc)) {
190 		fprintf(stderr, "Handled SIG_COPYCTX\n");
191 	} else {
192 		if (signum == SIGALRM && current->timeout) {
193 			fprintf(stderr, "-- Timeout !\n");
194 		} else {
195 			fprintf(stderr,
196 				"-- RX UNEXPECTED SIGNAL: %d\n", signum);
197 		}
198 		default_result(current, 1);
199 	}
200 }
201 
202 static int default_setup(struct tdescr *td)
203 {
204 	struct sigaction sa;
205 
206 	sa.sa_sigaction = default_handler;
207 	sa.sa_flags = SA_SIGINFO | SA_RESTART;
208 	sa.sa_flags |= td->sa_flags;
209 	sigemptyset(&sa.sa_mask);
210 	/* uncatchable signals naturally skipped ... */
211 	for (int sig = 1; sig < 32; sig++)
212 		sigaction(sig, &sa, NULL);
213 	/*
214 	 * RT Signals default disposition is Term but they cannot be
215 	 * generated by the Kernel in response to our tests; so just catch
216 	 * them all and report them as UNEXPECTED signals.
217 	 */
218 	for (int sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
219 		sigaction(sig, &sa, NULL);
220 
221 	/* just in case...unblock explicitly all we need */
222 	if (td->sig_trig)
223 		unblock_signal(td->sig_trig);
224 	if (td->sig_ok)
225 		unblock_signal(td->sig_ok);
226 	if (td->sig_unsupp)
227 		unblock_signal(td->sig_unsupp);
228 
229 	if (td->timeout) {
230 		unblock_signal(SIGALRM);
231 		alarm(td->timeout);
232 	}
233 	fprintf(stderr, "Registered handlers for all signals.\n");
234 
235 	return 1;
236 }
237 
238 static inline int default_trigger(struct tdescr *td)
239 {
240 	return !raise(td->sig_trig);
241 }
242 
243 int test_init(struct tdescr *td)
244 {
245 	if (td->sig_trig == sig_copyctx) {
246 		fprintf(stdout,
247 			"Signal %d is RESERVED, cannot be used as a trigger. Aborting\n",
248 			sig_copyctx);
249 		return 0;
250 	}
251 	/* just in case */
252 	unblock_signal(sig_copyctx);
253 
254 	td->minsigstksz = getauxval(AT_MINSIGSTKSZ);
255 	if (!td->minsigstksz)
256 		td->minsigstksz = MINSIGSTKSZ;
257 	fprintf(stderr, "Detected MINSTKSIGSZ:%d\n", td->minsigstksz);
258 
259 	if (td->feats_required) {
260 		td->feats_supported = 0;
261 		/*
262 		 * Checking for CPU required features using both the
263 		 * auxval and the arm64 MRS Emulation to read sysregs.
264 		 */
265 		if (getauxval(AT_HWCAP) & HWCAP_SSBS)
266 			td->feats_supported |= FEAT_SSBS;
267 		if (getauxval(AT_HWCAP) & HWCAP_SVE)
268 			td->feats_supported |= FEAT_SVE;
269 		if (feats_ok(td)) {
270 			fprintf(stderr,
271 				"Required Features: [%s] supported\n",
272 				feats_to_string(td->feats_required &
273 						td->feats_supported));
274 		} else {
275 			fprintf(stderr,
276 				"Required Features: [%s] NOT supported\n",
277 				feats_to_string(td->feats_required &
278 						~td->feats_supported));
279 			td->result = KSFT_SKIP;
280 			return 0;
281 		}
282 	}
283 
284 	/* Perform test specific additional initialization */
285 	if (td->init && !td->init(td)) {
286 		fprintf(stderr, "FAILED Testcase initialization.\n");
287 		return 0;
288 	}
289 	td->initialized = 1;
290 	fprintf(stderr, "Testcase initialized.\n");
291 
292 	return 1;
293 }
294 
295 int test_setup(struct tdescr *td)
296 {
297 	/* assert core invariants symptom of a rotten testcase */
298 	assert(current);
299 	assert(td);
300 	assert(td->name);
301 	assert(td->run);
302 
303 	/* Default result is FAIL if test setup fails */
304 	td->result = KSFT_FAIL;
305 	if (td->setup)
306 		return td->setup(td);
307 	else
308 		return default_setup(td);
309 }
310 
311 int test_run(struct tdescr *td)
312 {
313 	if (td->trigger)
314 		return td->trigger(td);
315 	else if (td->sig_trig)
316 		return default_trigger(td);
317 	else
318 		return td->run(td, NULL, NULL);
319 }
320 
321 void test_result(struct tdescr *td)
322 {
323 	if (td->initialized && td->result != KSFT_SKIP && td->check_result)
324 		td->check_result(td);
325 	default_result(td, 0);
326 }
327 
328 void test_cleanup(struct tdescr *td)
329 {
330 	if (td->cleanup)
331 		td->cleanup(td);
332 }
333