tools/testing/selftests/arm64/signal/test_signals_utils.c

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