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
23extern struct tdescr *current;
24
25static int sig_copyctx = SIGTRAP;
26
27static char const *const feats_names[FMAX_END] = {
28	" SSBS ",
29	" SVE ",
30	" SME ",
31	" FA64 ",
32	" SME2 ",
33};
34
35#define MAX_FEATS_SZ	128
36static char feats_string[MAX_FEATS_SZ];
37
38static inline char *feats_to_string(unsigned long feats)
39{
40	size_t flen = MAX_FEATS_SZ - 1;
41
42	feats_string[0] = '\0';
43
44	for (int i = 0; i < FMAX_END; i++) {
45		if (feats & (1UL << i)) {
46			size_t tlen = strlen(feats_names[i]);
47
48			assert(flen > tlen);
49			flen -= tlen;
50			strncat(feats_string, feats_names[i], flen);
51		}
52	}
53
54	return feats_string;
55}
56
57static void unblock_signal(int signum)
58{
59	sigset_t sset;
60
61	sigemptyset(&sset);
62	sigaddset(&sset, signum);
63	sigprocmask(SIG_UNBLOCK, &sset, NULL);
64}
65
66static void default_result(struct tdescr *td, bool force_exit)
67{
68	if (td->result == KSFT_SKIP) {
69		fprintf(stderr, "==>> completed. SKIP.\n");
70	} else if (td->pass) {
71		fprintf(stderr, "==>> completed. PASS(1)\n");
72		td->result = KSFT_PASS;
73	} else {
74		fprintf(stdout, "==>> completed. FAIL(0)\n");
75		td->result = KSFT_FAIL;
76	}
77
78	if (force_exit)
79		exit(td->result);
80}
81
82/*
83 * The following handle_signal_* helpers are used by main default_handler
84 * and are meant to return true when signal is handled successfully:
85 * when false is returned instead, it means that the signal was somehow
86 * unexpected in that context and it was NOT handled; default_handler will
87 * take care of such unexpected situations.
88 */
89
90static bool handle_signal_unsupported(struct tdescr *td,
91				      siginfo_t *si, void *uc)
92{
93	if (feats_ok(td))
94		return false;
95
96	/* Mangling PC to avoid loops on original SIGILL */
97	((ucontext_t *)uc)->uc_mcontext.pc += 4;
98
99	if (!td->initialized) {
100		fprintf(stderr,
101			"Got SIG_UNSUPP @test_init. Ignore.\n");
102	} else {
103		fprintf(stderr,
104			"-- RX SIG_UNSUPP on unsupported feat...OK\n");
105		td->pass = 1;
106		default_result(current, 1);
107	}
108
109	return true;
110}
111
112static bool handle_signal_trigger(struct tdescr *td,
113				  siginfo_t *si, void *uc)
114{
115	td->triggered = 1;
116	/* ->run was asserted NON-NULL in test_setup() already */
117	td->run(td, si, uc);
118
119	return true;
120}
121
122static bool handle_signal_ok(struct tdescr *td,
123			     siginfo_t *si, void *uc)
124{
125	/*
126	 * it's a bug in the test code when this assert fail:
127	 * if sig_trig was defined, it must have been used before getting here.
128	 */
129	assert(!td->sig_trig || td->triggered);
130	fprintf(stderr,
131		"SIG_OK -- SP:0x%llX  si_addr@:%p  si_code:%d  token@:%p  offset:%ld\n",
132		((ucontext_t *)uc)->uc_mcontext.sp,
133		si->si_addr, si->si_code, td->token, td->token - si->si_addr);
134	/*
135	 * fake_sigreturn tests, which have sanity_enabled=1, set, at the very
136	 * last time, the token field to the SP address used to place the fake
137	 * sigframe: so token==0 means we never made it to the end,
138	 * segfaulting well-before, and the test is possibly broken.
139	 */
140	if (!td->sanity_disabled && !td->token) {
141		fprintf(stdout,
142			"current->token ZEROED...test is probably broken!\n");
143		abort();
144	}
145	/*
146	 * Trying to narrow down the SEGV to the ones generated by Kernel itself
147	 * via arm64_notify_segfault(). This is a best-effort check anyway, and
148	 * the si_code check may need to change if this aspect of the kernel
149	 * ABI changes.
150	 */
151	if (td->sig_ok == SIGSEGV && si->si_code != SEGV_ACCERR) {
152		fprintf(stdout,
153			"si_code != SEGV_ACCERR...test is probably broken!\n");
154		abort();
155	}
156	td->pass = 1;
157	/*
158	 * Some tests can lead to SEGV loops: in such a case we want to
159	 * terminate immediately exiting straight away; some others are not
160	 * supposed to outlive the signal handler code, due to the content of
161	 * the fake sigframe which caused the signal itself.
162	 */
163	default_result(current, 1);
164
165	return true;
166}
167
168static bool handle_signal_copyctx(struct tdescr *td,
169				  siginfo_t *si, void *uc_in)
170{
171	ucontext_t *uc = uc_in;
172	struct _aarch64_ctx *head;
173	struct extra_context *extra, *copied_extra;
174	size_t offset = 0;
175	size_t to_copy;
176
177	ASSERT_GOOD_CONTEXT(uc);
178
179	/* Mangling PC to avoid loops on original BRK instr */
180	uc->uc_mcontext.pc += 4;
181
182	/*
183	 * Check for an preserve any extra data too with fixups.
184	 */
185	head = (struct _aarch64_ctx *)uc->uc_mcontext.__reserved;
186	head = get_header(head, EXTRA_MAGIC, td->live_sz, &offset);
187	if (head) {
188		extra = (struct extra_context *)head;
189
190		/*
191		 * The extra buffer must be immediately after the
192		 * extra_context and a 16 byte terminator. Include it
193		 * in the copy, this was previously validated in
194		 * ASSERT_GOOD_CONTEXT().
195		 */
196		to_copy = __builtin_offsetof(ucontext_t,
197					     uc_mcontext.__reserved);
198		to_copy += offset + sizeof(struct extra_context) + 16;
199		to_copy += extra->size;
200		copied_extra = (struct extra_context *)&(td->live_uc->uc_mcontext.__reserved[offset]);
201	} else {
202		copied_extra = NULL;
203		to_copy = sizeof(ucontext_t);
204	}
205
206	if (to_copy > td->live_sz) {
207		fprintf(stderr,
208			"Not enough space to grab context, %lu/%lu bytes\n",
209			td->live_sz, to_copy);
210		return false;
211	}
212
213	memcpy(td->live_uc, uc, to_copy);
214
215	/*
216	 * If there was any EXTRA_CONTEXT fix up the size to be the
217	 * struct extra_context and the following terminator record,
218	 * this means that the rest of the code does not need to have
219	 * special handling for the record and we don't need to fix up
220	 * datap for the new location.
221	 */
222	if (copied_extra)
223		copied_extra->head.size = sizeof(*copied_extra) + 16;
224
225	td->live_uc_valid = 1;
226	fprintf(stderr,
227		"%lu byte GOOD CONTEXT grabbed from sig_copyctx handler\n",
228		to_copy);
229
230	return true;
231}
232
233static void default_handler(int signum, siginfo_t *si, void *uc)
234{
235	if (current->sig_unsupp && signum == current->sig_unsupp &&
236	    handle_signal_unsupported(current, si, uc)) {
237		fprintf(stderr, "Handled SIG_UNSUPP\n");
238	} else if (current->sig_trig && signum == current->sig_trig &&
239		   handle_signal_trigger(current, si, uc)) {
240		fprintf(stderr, "Handled SIG_TRIG\n");
241	} else if (current->sig_ok && signum == current->sig_ok &&
242		   handle_signal_ok(current, si, uc)) {
243		fprintf(stderr, "Handled SIG_OK\n");
244	} else if (signum == sig_copyctx && current->live_uc &&
245		   handle_signal_copyctx(current, si, uc)) {
246		fprintf(stderr, "Handled SIG_COPYCTX\n");
247	} else {
248		if (signum == SIGALRM && current->timeout) {
249			fprintf(stderr, "-- Timeout !\n");
250		} else {
251			fprintf(stderr,
252				"-- RX UNEXPECTED SIGNAL: %d code %d address %p\n",
253				signum, si->si_code, si->si_addr);
254		}
255		default_result(current, 1);
256	}
257}
258
259static int default_setup(struct tdescr *td)
260{
261	struct sigaction sa;
262
263	sa.sa_sigaction = default_handler;
264	sa.sa_flags = SA_SIGINFO | SA_RESTART;
265	sa.sa_flags |= td->sa_flags;
266	sigemptyset(&sa.sa_mask);
267	/* uncatchable signals naturally skipped ... */
268	for (int sig = 1; sig < 32; sig++)
269		sigaction(sig, &sa, NULL);
270	/*
271	 * RT Signals default disposition is Term but they cannot be
272	 * generated by the Kernel in response to our tests; so just catch
273	 * them all and report them as UNEXPECTED signals.
274	 */
275	for (int sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
276		sigaction(sig, &sa, NULL);
277
278	/* just in case...unblock explicitly all we need */
279	if (td->sig_trig)
280		unblock_signal(td->sig_trig);
281	if (td->sig_ok)
282		unblock_signal(td->sig_ok);
283	if (td->sig_unsupp)
284		unblock_signal(td->sig_unsupp);
285
286	if (td->timeout) {
287		unblock_signal(SIGALRM);
288		alarm(td->timeout);
289	}
290	fprintf(stderr, "Registered handlers for all signals.\n");
291
292	return 1;
293}
294
295static inline int default_trigger(struct tdescr *td)
296{
297	return !raise(td->sig_trig);
298}
299
300int test_init(struct tdescr *td)
301{
302	if (td->sig_trig == sig_copyctx) {
303		fprintf(stdout,
304			"Signal %d is RESERVED, cannot be used as a trigger. Aborting\n",
305			sig_copyctx);
306		return 0;
307	}
308	/* just in case */
309	unblock_signal(sig_copyctx);
310
311	td->minsigstksz = getauxval(AT_MINSIGSTKSZ);
312	if (!td->minsigstksz)
313		td->minsigstksz = MINSIGSTKSZ;
314	fprintf(stderr, "Detected MINSTKSIGSZ:%d\n", td->minsigstksz);
315
316	if (td->feats_required || td->feats_incompatible) {
317		td->feats_supported = 0;
318		/*
319		 * Checking for CPU required features using both the
320		 * auxval and the arm64 MRS Emulation to read sysregs.
321		 */
322		if (getauxval(AT_HWCAP) & HWCAP_SSBS)
323			td->feats_supported |= FEAT_SSBS;
324		if (getauxval(AT_HWCAP) & HWCAP_SVE)
325			td->feats_supported |= FEAT_SVE;
326		if (getauxval(AT_HWCAP2) & HWCAP2_SME)
327			td->feats_supported |= FEAT_SME;
328		if (getauxval(AT_HWCAP2) & HWCAP2_SME_FA64)
329			td->feats_supported |= FEAT_SME_FA64;
330		if (getauxval(AT_HWCAP2) & HWCAP2_SME2)
331			td->feats_supported |= FEAT_SME2;
332		if (feats_ok(td)) {
333			if (td->feats_required & td->feats_supported)
334				fprintf(stderr,
335					"Required Features: [%s] supported\n",
336					feats_to_string(td->feats_required &
337							td->feats_supported));
338			if (!(td->feats_incompatible & td->feats_supported))
339				fprintf(stderr,
340					"Incompatible Features: [%s] absent\n",
341					feats_to_string(td->feats_incompatible));
342		} else {
343			if ((td->feats_required & td->feats_supported) !=
344			    td->feats_supported)
345				fprintf(stderr,
346					"Required Features: [%s] NOT supported\n",
347					feats_to_string(td->feats_required &
348							~td->feats_supported));
349			if (td->feats_incompatible & td->feats_supported)
350				fprintf(stderr,
351					"Incompatible Features: [%s] supported\n",
352					feats_to_string(td->feats_incompatible &
353							~td->feats_supported));
354
355
356			td->result = KSFT_SKIP;
357			return 0;
358		}
359	}
360
361	/* Perform test specific additional initialization */
362	if (td->init && !td->init(td)) {
363		fprintf(stderr, "FAILED Testcase initialization.\n");
364		return 0;
365	}
366	td->initialized = 1;
367	fprintf(stderr, "Testcase initialized.\n");
368
369	return 1;
370}
371
372int test_setup(struct tdescr *td)
373{
374	/* assert core invariants symptom of a rotten testcase */
375	assert(current);
376	assert(td);
377	assert(td->name);
378	assert(td->run);
379
380	/* Default result is FAIL if test setup fails */
381	td->result = KSFT_FAIL;
382	if (td->setup)
383		return td->setup(td);
384	else
385		return default_setup(td);
386}
387
388int test_run(struct tdescr *td)
389{
390	if (td->trigger)
391		return td->trigger(td);
392	else if (td->sig_trig)
393		return default_trigger(td);
394	else
395		return td->run(td, NULL, NULL);
396}
397
398void test_result(struct tdescr *td)
399{
400	if (td->initialized && td->result != KSFT_SKIP && td->check_result)
401		td->check_result(td);
402	default_result(td, 0);
403}
404
405void test_cleanup(struct tdescr *td)
406{
407	if (td->cleanup)
408		td->cleanup(td);
409}
410