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 	" SME ",
31 	" FA64 ",
32 };
33 
34 #define MAX_FEATS_SZ	128
35 static char feats_string[MAX_FEATS_SZ];
36 
37 static inline char *feats_to_string(unsigned long feats)
38 {
39 	size_t flen = MAX_FEATS_SZ - 1;
40 
41 	feats_string[0] = '\0';
42 
43 	for (int i = 0; i < FMAX_END; i++) {
44 		if (feats & (1UL << i)) {
45 			size_t tlen = strlen(feats_names[i]);
46 
47 			assert(flen > tlen);
48 			flen -= tlen;
49 			strncat(feats_string, feats_names[i], flen);
50 		}
51 	}
52 
53 	return feats_string;
54 }
55 
56 static void unblock_signal(int signum)
57 {
58 	sigset_t sset;
59 
60 	sigemptyset(&sset);
61 	sigaddset(&sset, signum);
62 	sigprocmask(SIG_UNBLOCK, &sset, NULL);
63 }
64 
65 static void default_result(struct tdescr *td, bool force_exit)
66 {
67 	if (td->result == KSFT_SKIP) {
68 		fprintf(stderr, "==>> completed. SKIP.\n");
69 	} else if (td->pass) {
70 		fprintf(stderr, "==>> completed. PASS(1)\n");
71 		td->result = KSFT_PASS;
72 	} else {
73 		fprintf(stdout, "==>> completed. FAIL(0)\n");
74 		td->result = KSFT_FAIL;
75 	}
76 
77 	if (force_exit)
78 		exit(td->result);
79 }
80 
81 /*
82  * The following handle_signal_* helpers are used by main default_handler
83  * and are meant to return true when signal is handled successfully:
84  * when false is returned instead, it means that the signal was somehow
85  * unexpected in that context and it was NOT handled; default_handler will
86  * take care of such unexpected situations.
87  */
88 
89 static bool handle_signal_unsupported(struct tdescr *td,
90 				      siginfo_t *si, void *uc)
91 {
92 	if (feats_ok(td))
93 		return false;
94 
95 	/* Mangling PC to avoid loops on original SIGILL */
96 	((ucontext_t *)uc)->uc_mcontext.pc += 4;
97 
98 	if (!td->initialized) {
99 		fprintf(stderr,
100 			"Got SIG_UNSUPP @test_init. Ignore.\n");
101 	} else {
102 		fprintf(stderr,
103 			"-- RX SIG_UNSUPP on unsupported feat...OK\n");
104 		td->pass = 1;
105 		default_result(current, 1);
106 	}
107 
108 	return true;
109 }
110 
111 static bool handle_signal_trigger(struct tdescr *td,
112 				  siginfo_t *si, void *uc)
113 {
114 	td->triggered = 1;
115 	/* ->run was asserted NON-NULL in test_setup() already */
116 	td->run(td, si, uc);
117 
118 	return true;
119 }
120 
121 static bool handle_signal_ok(struct tdescr *td,
122 			     siginfo_t *si, void *uc)
123 {
124 	/*
125 	 * it's a bug in the test code when this assert fail:
126 	 * if sig_trig was defined, it must have been used before getting here.
127 	 */
128 	assert(!td->sig_trig || td->triggered);
129 	fprintf(stderr,
130 		"SIG_OK -- SP:0x%llX  si_addr@:%p  si_code:%d  token@:%p  offset:%ld\n",
131 		((ucontext_t *)uc)->uc_mcontext.sp,
132 		si->si_addr, si->si_code, td->token, td->token - si->si_addr);
133 	/*
134 	 * fake_sigreturn tests, which have sanity_enabled=1, set, at the very
135 	 * last time, the token field to the SP address used to place the fake
136 	 * sigframe: so token==0 means we never made it to the end,
137 	 * segfaulting well-before, and the test is possibly broken.
138 	 */
139 	if (!td->sanity_disabled && !td->token) {
140 		fprintf(stdout,
141 			"current->token ZEROED...test is probably broken!\n");
142 		abort();
143 	}
144 	/*
145 	 * Trying to narrow down the SEGV to the ones generated by Kernel itself
146 	 * via arm64_notify_segfault(). This is a best-effort check anyway, and
147 	 * the si_code check may need to change if this aspect of the kernel
148 	 * ABI changes.
149 	 */
150 	if (td->sig_ok == SIGSEGV && si->si_code != SEGV_ACCERR) {
151 		fprintf(stdout,
152 			"si_code != SEGV_ACCERR...test is probably broken!\n");
153 		abort();
154 	}
155 	td->pass = 1;
156 	/*
157 	 * Some tests can lead to SEGV loops: in such a case we want to
158 	 * terminate immediately exiting straight away; some others are not
159 	 * supposed to outlive the signal handler code, due to the content of
160 	 * the fake sigframe which caused the signal itself.
161 	 */
162 	default_result(current, 1);
163 
164 	return true;
165 }
166 
167 static bool handle_signal_copyctx(struct tdescr *td,
168 				  siginfo_t *si, void *uc_in)
169 {
170 	ucontext_t *uc = uc_in;
171 	struct _aarch64_ctx *head;
172 	struct extra_context *extra, *copied_extra;
173 	size_t offset = 0;
174 	size_t to_copy;
175 
176 	ASSERT_GOOD_CONTEXT(uc);
177 
178 	/* Mangling PC to avoid loops on original BRK instr */
179 	uc->uc_mcontext.pc += 4;
180 
181 	/*
182 	 * Check for an preserve any extra data too with fixups.
183 	 */
184 	head = (struct _aarch64_ctx *)uc->uc_mcontext.__reserved;
185 	head = get_header(head, EXTRA_MAGIC, td->live_sz, &offset);
186 	if (head) {
187 		extra = (struct extra_context *)head;
188 
189 		/*
190 		 * The extra buffer must be immediately after the
191 		 * extra_context and a 16 byte terminator. Include it
192 		 * in the copy, this was previously validated in
193 		 * ASSERT_GOOD_CONTEXT().
194 		 */
195 		to_copy = offset + sizeof(struct extra_context) + 16 +
196 			extra->size;
197 		copied_extra = (struct extra_context *)&(td->live_uc->uc_mcontext.__reserved[offset]);
198 	} else {
199 		copied_extra = NULL;
200 		to_copy = sizeof(ucontext_t);
201 	}
202 
203 	if (to_copy > td->live_sz) {
204 		fprintf(stderr,
205 			"Not enough space to grab context, %lu/%lu bytes\n",
206 			td->live_sz, to_copy);
207 		return false;
208 	}
209 
210 	memcpy(td->live_uc, uc, to_copy);
211 
212 	/*
213 	 * If there was any EXTRA_CONTEXT fix up the size to be the
214 	 * struct extra_context and the following terminator record,
215 	 * this means that the rest of the code does not need to have
216 	 * special handling for the record and we don't need to fix up
217 	 * datap for the new location.
218 	 */
219 	if (copied_extra)
220 		copied_extra->head.size = sizeof(*copied_extra) + 16;
221 
222 	td->live_uc_valid = 1;
223 	fprintf(stderr,
224 		"%lu byte GOOD CONTEXT grabbed from sig_copyctx handler\n",
225 		to_copy);
226 
227 	return true;
228 }
229 
230 static void default_handler(int signum, siginfo_t *si, void *uc)
231 {
232 	if (current->sig_unsupp && signum == current->sig_unsupp &&
233 	    handle_signal_unsupported(current, si, uc)) {
234 		fprintf(stderr, "Handled SIG_UNSUPP\n");
235 	} else if (current->sig_trig && signum == current->sig_trig &&
236 		   handle_signal_trigger(current, si, uc)) {
237 		fprintf(stderr, "Handled SIG_TRIG\n");
238 	} else if (current->sig_ok && signum == current->sig_ok &&
239 		   handle_signal_ok(current, si, uc)) {
240 		fprintf(stderr, "Handled SIG_OK\n");
241 	} else if (signum == sig_copyctx && current->live_uc &&
242 		   handle_signal_copyctx(current, si, uc)) {
243 		fprintf(stderr, "Handled SIG_COPYCTX\n");
244 	} else {
245 		if (signum == SIGALRM && current->timeout) {
246 			fprintf(stderr, "-- Timeout !\n");
247 		} else {
248 			fprintf(stderr,
249 				"-- RX UNEXPECTED SIGNAL: %d\n", signum);
250 		}
251 		default_result(current, 1);
252 	}
253 }
254 
255 static int default_setup(struct tdescr *td)
256 {
257 	struct sigaction sa;
258 
259 	sa.sa_sigaction = default_handler;
260 	sa.sa_flags = SA_SIGINFO | SA_RESTART;
261 	sa.sa_flags |= td->sa_flags;
262 	sigemptyset(&sa.sa_mask);
263 	/* uncatchable signals naturally skipped ... */
264 	for (int sig = 1; sig < 32; sig++)
265 		sigaction(sig, &sa, NULL);
266 	/*
267 	 * RT Signals default disposition is Term but they cannot be
268 	 * generated by the Kernel in response to our tests; so just catch
269 	 * them all and report them as UNEXPECTED signals.
270 	 */
271 	for (int sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
272 		sigaction(sig, &sa, NULL);
273 
274 	/* just in case...unblock explicitly all we need */
275 	if (td->sig_trig)
276 		unblock_signal(td->sig_trig);
277 	if (td->sig_ok)
278 		unblock_signal(td->sig_ok);
279 	if (td->sig_unsupp)
280 		unblock_signal(td->sig_unsupp);
281 
282 	if (td->timeout) {
283 		unblock_signal(SIGALRM);
284 		alarm(td->timeout);
285 	}
286 	fprintf(stderr, "Registered handlers for all signals.\n");
287 
288 	return 1;
289 }
290 
291 static inline int default_trigger(struct tdescr *td)
292 {
293 	return !raise(td->sig_trig);
294 }
295 
296 int test_init(struct tdescr *td)
297 {
298 	if (td->sig_trig == sig_copyctx) {
299 		fprintf(stdout,
300 			"Signal %d is RESERVED, cannot be used as a trigger. Aborting\n",
301 			sig_copyctx);
302 		return 0;
303 	}
304 	/* just in case */
305 	unblock_signal(sig_copyctx);
306 
307 	td->minsigstksz = getauxval(AT_MINSIGSTKSZ);
308 	if (!td->minsigstksz)
309 		td->minsigstksz = MINSIGSTKSZ;
310 	fprintf(stderr, "Detected MINSTKSIGSZ:%d\n", td->minsigstksz);
311 
312 	if (td->feats_required || td->feats_incompatible) {
313 		td->feats_supported = 0;
314 		/*
315 		 * Checking for CPU required features using both the
316 		 * auxval and the arm64 MRS Emulation to read sysregs.
317 		 */
318 		if (getauxval(AT_HWCAP) & HWCAP_SSBS)
319 			td->feats_supported |= FEAT_SSBS;
320 		if (getauxval(AT_HWCAP) & HWCAP_SVE)
321 			td->feats_supported |= FEAT_SVE;
322 		if (getauxval(AT_HWCAP2) & HWCAP2_SME)
323 			td->feats_supported |= FEAT_SME;
324 		if (getauxval(AT_HWCAP2) & HWCAP2_SME_FA64)
325 			td->feats_supported |= FEAT_SME_FA64;
326 		if (feats_ok(td)) {
327 			if (td->feats_required & td->feats_supported)
328 				fprintf(stderr,
329 					"Required Features: [%s] supported\n",
330 					feats_to_string(td->feats_required &
331 							td->feats_supported));
332 			if (!(td->feats_incompatible & td->feats_supported))
333 				fprintf(stderr,
334 					"Incompatible Features: [%s] absent\n",
335 					feats_to_string(td->feats_incompatible));
336 		} else {
337 			if ((td->feats_required & td->feats_supported) !=
338 			    td->feats_supported)
339 				fprintf(stderr,
340 					"Required Features: [%s] NOT supported\n",
341 					feats_to_string(td->feats_required &
342 							~td->feats_supported));
343 			if (td->feats_incompatible & td->feats_supported)
344 				fprintf(stderr,
345 					"Incompatible Features: [%s] supported\n",
346 					feats_to_string(td->feats_incompatible &
347 							~td->feats_supported));
348 
349 
350 			td->result = KSFT_SKIP;
351 			return 0;
352 		}
353 	}
354 
355 	/* Perform test specific additional initialization */
356 	if (td->init && !td->init(td)) {
357 		fprintf(stderr, "FAILED Testcase initialization.\n");
358 		return 0;
359 	}
360 	td->initialized = 1;
361 	fprintf(stderr, "Testcase initialized.\n");
362 
363 	return 1;
364 }
365 
366 int test_setup(struct tdescr *td)
367 {
368 	/* assert core invariants symptom of a rotten testcase */
369 	assert(current);
370 	assert(td);
371 	assert(td->name);
372 	assert(td->run);
373 
374 	/* Default result is FAIL if test setup fails */
375 	td->result = KSFT_FAIL;
376 	if (td->setup)
377 		return td->setup(td);
378 	else
379 		return default_setup(td);
380 }
381 
382 int test_run(struct tdescr *td)
383 {
384 	if (td->trigger)
385 		return td->trigger(td);
386 	else if (td->sig_trig)
387 		return default_trigger(td);
388 	else
389 		return td->run(td, NULL, NULL);
390 }
391 
392 void test_result(struct tdescr *td)
393 {
394 	if (td->initialized && td->result != KSFT_SKIP && td->check_result)
395 		td->check_result(td);
396 	default_result(td, 0);
397 }
398 
399 void test_cleanup(struct tdescr *td)
400 {
401 	if (td->cleanup)
402 		td->cleanup(td);
403 }
404