linux-user/aarch64/signal.c

   1 /*
   2  *  Emulation of Linux signals
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include "qemu/osdep.h"
  20 #include "qemu.h"
  21 #include "signal-common.h"
  22 #include "linux-user/trace.h"
  23
  24 struct target_sigcontext {
  25     uint64_t fault_address;
  26     /* AArch64 registers */
  27     uint64_t regs[31];
  28     uint64_t sp;
  29     uint64_t pc;
  30     uint64_t pstate;
  31     /* 4K reserved for FP/SIMD state and future expansion */
  32     char __reserved[4096] __attribute__((__aligned__(16)));
  33 };
  34
  35 struct target_ucontext {
  36     abi_ulong tuc_flags;
  37     abi_ulong tuc_link;
  38     target_stack_t tuc_stack;
  39     target_sigset_t tuc_sigmask;
  40     /* glibc uses a 1024-bit sigset_t */
  41     char __unused[1024 / 8 - sizeof(target_sigset_t)];
  42     /* last for future expansion */
  43     struct target_sigcontext tuc_mcontext;
  44 };
  45
  46 /*
  47  * Header to be used at the beginning of structures extending the user
  48  * context. Such structures must be placed after the rt_sigframe on the stack
  49  * and be 16-byte aligned. The last structure must be a dummy one with the
  50  * magic and size set to 0.
  51  */
  52 struct target_aarch64_ctx {
  53     uint32_t magic;
  54     uint32_t size;
  55 };
  56
  57 #define TARGET_FPSIMD_MAGIC 0x46508001
  58
  59 struct target_fpsimd_context {
  60     struct target_aarch64_ctx head;
  61     uint32_t fpsr;
  62     uint32_t fpcr;
  63     uint64_t vregs[32 * 2]; /* really uint128_t vregs[32] */
  64 };
  65
  66 #define TARGET_EXTRA_MAGIC  0x45585401
  67
  68 struct target_extra_context {
  69     struct target_aarch64_ctx head;
  70     uint64_t datap; /* 16-byte aligned pointer to extra space cast to __u64 */
  71     uint32_t size; /* size in bytes of the extra space */
  72     uint32_t reserved[3];
  73 };
  74
  75 #define TARGET_SVE_MAGIC    0x53564501
  76
  77 struct target_sve_context {
  78     struct target_aarch64_ctx head;
  79     uint16_t vl;
  80     uint16_t reserved[3];
  81     /* The actual SVE data immediately follows.  It is laid out
  82      * according to TARGET_SVE_SIG_{Z,P}REG_OFFSET, based off of
  83      * the original struct pointer.
  84      */
  85 };
  86
  87 #define TARGET_SVE_VQ_BYTES  16
  88
  89 #define TARGET_SVE_SIG_ZREG_SIZE(VQ)  ((VQ) * TARGET_SVE_VQ_BYTES)
  90 #define TARGET_SVE_SIG_PREG_SIZE(VQ)  ((VQ) * (TARGET_SVE_VQ_BYTES / 8))
  91
  92 #define TARGET_SVE_SIG_REGS_OFFSET \
  93     QEMU_ALIGN_UP(sizeof(struct target_sve_context), TARGET_SVE_VQ_BYTES)
  94 #define TARGET_SVE_SIG_ZREG_OFFSET(VQ, N) \
  95     (TARGET_SVE_SIG_REGS_OFFSET + TARGET_SVE_SIG_ZREG_SIZE(VQ) * (N))
  96 #define TARGET_SVE_SIG_PREG_OFFSET(VQ, N) \
  97     (TARGET_SVE_SIG_ZREG_OFFSET(VQ, 32) + TARGET_SVE_SIG_PREG_SIZE(VQ) * (N))
  98 #define TARGET_SVE_SIG_FFR_OFFSET(VQ) \
  99     (TARGET_SVE_SIG_PREG_OFFSET(VQ, 16))
 100 #define TARGET_SVE_SIG_CONTEXT_SIZE(VQ) \
 101     (TARGET_SVE_SIG_PREG_OFFSET(VQ, 17))
 102
 103 struct target_rt_sigframe {
 104     struct target_siginfo info;
 105     struct target_ucontext uc;
 106 };
 107
 108 struct target_rt_frame_record {
 109     uint64_t fp;
 110     uint64_t lr;
 111     uint32_t tramp[2];
 112 };
 113
 114 static void target_setup_general_frame(struct target_rt_sigframe *sf,
 115                                        CPUARMState *env, target_sigset_t *set)
 116 {
 117     int i;
 118
 119     __put_user(0, &sf->uc.tuc_flags);
 120     __put_user(0, &sf->uc.tuc_link);
 121
 122     target_save_altstack(&sf->uc.tuc_stack, env);
 123
 124     for (i = 0; i < 31; i++) {
 125         __put_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
 126     }
 127     __put_user(env->xregs[31], &sf->uc.tuc_mcontext.sp);
 128     __put_user(env->pc, &sf->uc.tuc_mcontext.pc);
 129     __put_user(pstate_read(env), &sf->uc.tuc_mcontext.pstate);
 130
 131     __put_user(env->exception.vaddress, &sf->uc.tuc_mcontext.fault_address);
 132
 133     for (i = 0; i < TARGET_NSIG_WORDS; i++) {
 134         __put_user(set->sig[i], &sf->uc.tuc_sigmask.sig[i]);
 135     }
 136 }
 137
 138 static void target_setup_fpsimd_record(struct target_fpsimd_context *fpsimd,
 139                                        CPUARMState *env)
 140 {
 141     int i;
 142
 143     __put_user(TARGET_FPSIMD_MAGIC, &fpsimd->head.magic);
 144     __put_user(sizeof(struct target_fpsimd_context), &fpsimd->head.size);
 145     __put_user(vfp_get_fpsr(env), &fpsimd->fpsr);
 146     __put_user(vfp_get_fpcr(env), &fpsimd->fpcr);
 147
 148     for (i = 0; i < 32; i++) {
 149         uint64_t *q = aa64_vfp_qreg(env, i);
 150 #ifdef TARGET_WORDS_BIGENDIAN
 151         __put_user(q[0], &fpsimd->vregs[i * 2 + 1]);
 152         __put_user(q[1], &fpsimd->vregs[i * 2]);
 153 #else
 154         __put_user(q[0], &fpsimd->vregs[i * 2]);
 155         __put_user(q[1], &fpsimd->vregs[i * 2 + 1]);
 156 #endif
 157     }
 158 }
 159
 160 static void target_setup_extra_record(struct target_extra_context *extra,
 161                                       uint64_t datap, uint32_t extra_size)
 162 {
 163     __put_user(TARGET_EXTRA_MAGIC, &extra->head.magic);
 164     __put_user(sizeof(struct target_extra_context), &extra->head.size);
 165     __put_user(datap, &extra->datap);
 166     __put_user(extra_size, &extra->size);
 167 }
 168
 169 static void target_setup_end_record(struct target_aarch64_ctx *end)
 170 {
 171     __put_user(0, &end->magic);
 172     __put_user(0, &end->size);
 173 }
 174
 175 static void target_setup_sve_record(struct target_sve_context *sve,
 176                                     CPUARMState *env, int vq, int size)
 177 {
 178     int i, j;
 179
 180     __put_user(TARGET_SVE_MAGIC, &sve->head.magic);
 181     __put_user(size, &sve->head.size);
 182     __put_user(vq * TARGET_SVE_VQ_BYTES, &sve->vl);
 183
 184     /* Note that SVE regs are stored as a byte stream, with each byte element
 185      * at a subsequent address.  This corresponds to a little-endian store
 186      * of our 64-bit hunks.
 187      */
 188     for (i = 0; i < 32; ++i) {
 189         uint64_t *z = (void *)sve + TARGET_SVE_SIG_ZREG_OFFSET(vq, i);
 190         for (j = 0; j < vq * 2; ++j) {
 191             __put_user_e(env->vfp.zregs[i].d[j], z + j, le);
 192         }
 193     }
 194     for (i = 0; i <= 16; ++i) {
 195         uint16_t *p = (void *)sve + TARGET_SVE_SIG_PREG_OFFSET(vq, i);
 196         for (j = 0; j < vq; ++j) {
 197             uint64_t r = env->vfp.pregs[i].p[j >> 2];
 198             __put_user_e(r >> ((j & 3) * 16), p + j, le);
 199         }
 200     }
 201 }
 202
 203 static void target_restore_general_frame(CPUARMState *env,
 204                                          struct target_rt_sigframe *sf)
 205 {
 206     sigset_t set;
 207     uint64_t pstate;
 208     int i;
 209
 210     target_to_host_sigset(&set, &sf->uc.tuc_sigmask);
 211     set_sigmask(&set);
 212
 213     for (i = 0; i < 31; i++) {
 214         __get_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
 215     }
 216
 217     __get_user(env->xregs[31], &sf->uc.tuc_mcontext.sp);
 218     __get_user(env->pc, &sf->uc.tuc_mcontext.pc);
 219     __get_user(pstate, &sf->uc.tuc_mcontext.pstate);
 220     pstate_write(env, pstate);
 221 }
 222
 223 static void target_restore_fpsimd_record(CPUARMState *env,
 224                                          struct target_fpsimd_context *fpsimd)
 225 {
 226     uint32_t fpsr, fpcr;
 227     int i;
 228
 229     __get_user(fpsr, &fpsimd->fpsr);
 230     vfp_set_fpsr(env, fpsr);
 231     __get_user(fpcr, &fpsimd->fpcr);
 232     vfp_set_fpcr(env, fpcr);
 233
 234     for (i = 0; i < 32; i++) {
 235         uint64_t *q = aa64_vfp_qreg(env, i);
 236 #ifdef TARGET_WORDS_BIGENDIAN
 237         __get_user(q[0], &fpsimd->vregs[i * 2 + 1]);
 238         __get_user(q[1], &fpsimd->vregs[i * 2]);
 239 #else
 240         __get_user(q[0], &fpsimd->vregs[i * 2]);
 241         __get_user(q[1], &fpsimd->vregs[i * 2 + 1]);
 242 #endif
 243     }
 244 }
 245
 246 static void target_restore_sve_record(CPUARMState *env,
 247                                       struct target_sve_context *sve, int vq)
 248 {
 249     int i, j;
 250
 251     /* Note that SVE regs are stored as a byte stream, with each byte element
 252      * at a subsequent address.  This corresponds to a little-endian load
 253      * of our 64-bit hunks.
 254      */
 255     for (i = 0; i < 32; ++i) {
 256         uint64_t *z = (void *)sve + TARGET_SVE_SIG_ZREG_OFFSET(vq, i);
 257         for (j = 0; j < vq * 2; ++j) {
 258             __get_user_e(env->vfp.zregs[i].d[j], z + j, le);
 259         }
 260     }
 261     for (i = 0; i <= 16; ++i) {
 262         uint16_t *p = (void *)sve + TARGET_SVE_SIG_PREG_OFFSET(vq, i);
 263         for (j = 0; j < vq; ++j) {
 264             uint16_t r;
 265             __get_user_e(r, p + j, le);
 266             if (j & 3) {
 267                 env->vfp.pregs[i].p[j >> 2] |= (uint64_t)r << ((j & 3) * 16);
 268             } else {
 269                 env->vfp.pregs[i].p[j >> 2] = r;
 270             }
 271         }
 272     }
 273 }
 274
 275 static int target_restore_sigframe(CPUARMState *env,
 276                                    struct target_rt_sigframe *sf)
 277 {
 278     struct target_aarch64_ctx *ctx, *extra = NULL;
 279     struct target_fpsimd_context *fpsimd = NULL;
 280     struct target_sve_context *sve = NULL;
 281     uint64_t extra_datap = 0;
 282     bool used_extra = false;
 283     bool err = false;
 284     int vq = 0, sve_size = 0;
 285
 286     target_restore_general_frame(env, sf);
 287
 288     ctx = (struct target_aarch64_ctx *)sf->uc.tuc_mcontext.__reserved;
 289     while (ctx) {
 290         uint32_t magic, size, extra_size;
 291
 292         __get_user(magic, &ctx->magic);
 293         __get_user(size, &ctx->size);
 294         switch (magic) {
 295         case 0:
 296             if (size != 0) {
 297                 err = true;
 298                 goto exit;
 299             }
 300             if (used_extra) {
 301                 ctx = NULL;
 302             } else {
 303                 ctx = extra;
 304                 used_extra = true;
 305             }
 306             continue;
 307
 308         case TARGET_FPSIMD_MAGIC:
 309             if (fpsimd || size != sizeof(struct target_fpsimd_context)) {
 310                 err = true;
 311                 goto exit;
 312             }
 313             fpsimd = (struct target_fpsimd_context *)ctx;
 314             break;
 315
 316         case TARGET_SVE_MAGIC:
 317             if (cpu_isar_feature(aa64_sve, env_archcpu(env))) {
 318                 vq = (env->vfp.zcr_el[1] & 0xf) + 1;
 319                 sve_size = QEMU_ALIGN_UP(TARGET_SVE_SIG_CONTEXT_SIZE(vq), 16);
 320                 if (!sve && size == sve_size) {
 321                     sve = (struct target_sve_context *)ctx;
 322                     break;
 323                 }
 324             }
 325             err = true;
 326             goto exit;
 327
 328         case TARGET_EXTRA_MAGIC:
 329             if (extra || size != sizeof(struct target_extra_context)) {
 330                 err = true;
 331                 goto exit;
 332             }
 333             __get_user(extra_datap,
 334                        &((struct target_extra_context *)ctx)->datap);
 335             __get_user(extra_size,
 336                        &((struct target_extra_context *)ctx)->size);
 337             extra = lock_user(VERIFY_READ, extra_datap, extra_size, 0);
 338             break;
 339
 340         default:
 341             /* Unknown record -- we certainly didn't generate it.
 342              * Did we in fact get out of sync?
 343              */
 344             err = true;
 345             goto exit;
 346         }
 347         ctx = (void *)ctx + size;
 348     }
 349
 350     /* Require FPSIMD always.  */
 351     if (fpsimd) {
 352         target_restore_fpsimd_record(env, fpsimd);
 353     } else {
 354         err = true;
 355     }
 356
 357     /* SVE data, if present, overwrites FPSIMD data.  */
 358     if (sve) {
 359         target_restore_sve_record(env, sve, vq);
 360     }
 361
 362  exit:
 363     unlock_user(extra, extra_datap, 0);
 364     return err;
 365 }
 366
 367 static abi_ulong get_sigframe(struct target_sigaction *ka,
 368                               CPUARMState *env, int size)
 369 {
 370     abi_ulong sp;
 371
 372     sp = target_sigsp(get_sp_from_cpustate(env), ka);
 373
 374     sp = (sp - size) & ~15;
 375
 376     return sp;
 377 }
 378
 379 typedef struct {
 380     int total_size;
 381     int extra_base;
 382     int extra_size;
 383     int std_end_ofs;
 384     int extra_ofs;
 385     int extra_end_ofs;
 386 } target_sigframe_layout;
 387
 388 static int alloc_sigframe_space(int this_size, target_sigframe_layout *l)
 389 {
 390     /* Make sure there will always be space for the end marker.  */
 391     const int std_size = sizeof(struct target_rt_sigframe)
 392                          - sizeof(struct target_aarch64_ctx);
 393     int this_loc = l->total_size;
 394
 395     if (l->extra_base) {
 396         /* Once we have begun an extra space, all allocations go there.  */
 397         l->extra_size += this_size;
 398     } else if (this_size + this_loc > std_size) {
 399         /* This allocation does not fit in the standard space.  */
 400         /* Allocate the extra record.  */
 401         l->extra_ofs = this_loc;
 402         l->total_size += sizeof(struct target_extra_context);
 403
 404         /* Allocate the standard end record.  */
 405         l->std_end_ofs = l->total_size;
 406         l->total_size += sizeof(struct target_aarch64_ctx);
 407
 408         /* Allocate the requested record.  */
 409         l->extra_base = this_loc = l->total_size;
 410         l->extra_size = this_size;
 411     }
 412     l->total_size += this_size;
 413
 414     return this_loc;
 415 }
 416
 417 static void target_setup_frame(int usig, struct target_sigaction *ka,
 418                                target_siginfo_t *info, target_sigset_t *set,
 419                                CPUARMState *env)
 420 {
 421     target_sigframe_layout layout = {
 422         /* Begin with the size pointing to the reserved space.  */
 423         .total_size = offsetof(struct target_rt_sigframe,
 424                                uc.tuc_mcontext.__reserved),
 425     };
 426     int fpsimd_ofs, fr_ofs, sve_ofs = 0, vq = 0, sve_size = 0;
 427     struct target_rt_sigframe *frame;
 428     struct target_rt_frame_record *fr;
 429     abi_ulong frame_addr, return_addr;
 430
 431     /* FPSIMD record is always in the standard space.  */
 432     fpsimd_ofs = alloc_sigframe_space(sizeof(struct target_fpsimd_context),
 433                                       &layout);
 434
 435     /* SVE state needs saving only if it exists.  */
 436     if (cpu_isar_feature(aa64_sve, env_archcpu(env))) {
 437         vq = (env->vfp.zcr_el[1] & 0xf) + 1;
 438         sve_size = QEMU_ALIGN_UP(TARGET_SVE_SIG_CONTEXT_SIZE(vq), 16);
 439         sve_ofs = alloc_sigframe_space(sve_size, &layout);
 440     }
 441
 442     if (layout.extra_ofs) {
 443         /* Reserve space for the extra end marker.  The standard end marker
 444          * will have been allocated when we allocated the extra record.
 445          */
 446         layout.extra_end_ofs
 447             = alloc_sigframe_space(sizeof(struct target_aarch64_ctx), &layout);
 448     } else {
 449         /* Reserve space for the standard end marker.
 450          * Do not use alloc_sigframe_space because we cheat
 451          * std_size therein to reserve space for this.
 452          */
 453         layout.std_end_ofs = layout.total_size;
 454         layout.total_size += sizeof(struct target_aarch64_ctx);
 455     }
 456
 457     /* We must always provide at least the standard 4K reserved space,
 458      * even if we don't use all of it (this is part of the ABI)
 459      */
 460     layout.total_size = MAX(layout.total_size,
 461                             sizeof(struct target_rt_sigframe));
 462
 463     /* Reserve space for the return code.  On a real system this would
 464      * be within the VDSO.  So, despite the name this is not a "real"
 465      * record within the frame.
 466      */
 467     fr_ofs = layout.total_size;
 468     layout.total_size += sizeof(struct target_rt_frame_record);
 469
 470     frame_addr = get_sigframe(ka, env, layout.total_size);
 471     trace_user_setup_frame(env, frame_addr);
 472     frame = lock_user(VERIFY_WRITE, frame_addr, layout.total_size, 0);
 473     if (!frame) {
 474         goto give_sigsegv;
 475     }
 476
 477     target_setup_general_frame(frame, env, set);
 478     target_setup_fpsimd_record((void *)frame + fpsimd_ofs, env);
 479     target_setup_end_record((void *)frame + layout.std_end_ofs);
 480     if (layout.extra_ofs) {
 481         target_setup_extra_record((void *)frame + layout.extra_ofs,
 482                                   frame_addr + layout.extra_base,
 483                                   layout.extra_size);
 484         target_setup_end_record((void *)frame + layout.extra_end_ofs);
 485     }
 486     if (sve_ofs) {
 487         target_setup_sve_record((void *)frame + sve_ofs, env, vq, sve_size);
 488     }
 489
 490     /* Set up the stack frame for unwinding.  */
 491     fr = (void *)frame + fr_ofs;
 492     __put_user(env->xregs[29], &fr->fp);
 493     __put_user(env->xregs[30], &fr->lr);
 494
 495     if (ka->sa_flags & TARGET_SA_RESTORER) {
 496         return_addr = ka->sa_restorer;
 497     } else {
 498         /*
 499          * mov x8,#__NR_rt_sigreturn; svc #0
 500          * Since these are instructions they need to be put as little-endian
 501          * regardless of target default or current CPU endianness.
 502          */
 503         __put_user_e(0xd2801168, &fr->tramp[0], le);
 504         __put_user_e(0xd4000001, &fr->tramp[1], le);
 505         return_addr = frame_addr + fr_ofs
 506             + offsetof(struct target_rt_frame_record, tramp);
 507     }
 508     env->xregs[0] = usig;
 509     env->xregs[29] = frame_addr + fr_ofs;
 510     env->xregs[30] = return_addr;
 511     env->xregs[31] = frame_addr;
 512     env->pc = ka->_sa_handler;
 513
 514     /* Invoke the signal handler as if by indirect call.  */
 515     if (cpu_isar_feature(aa64_bti, env_archcpu(env))) {
 516         env->btype = 2;
 517     }
 518
 519     if (info) {
 520         tswap_siginfo(&frame->info, info);
 521         env->xregs[1] = frame_addr + offsetof(struct target_rt_sigframe, info);
 522         env->xregs[2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
 523     }
 524
 525     unlock_user(frame, frame_addr, layout.total_size);
 526     return;
 527
 528  give_sigsegv:
 529     unlock_user(frame, frame_addr, layout.total_size);
 530     force_sigsegv(usig);
 531 }
 532
 533 void setup_rt_frame(int sig, struct target_sigaction *ka,
 534                     target_siginfo_t *info, target_sigset_t *set,
 535                     CPUARMState *env)
 536 {
 537     target_setup_frame(sig, ka, info, set, env);
 538 }
 539
 540 void setup_frame(int sig, struct target_sigaction *ka,
 541                  target_sigset_t *set, CPUARMState *env)
 542 {
 543     target_setup_frame(sig, ka, 0, set, env);
 544 }
 545
 546 long do_rt_sigreturn(CPUARMState *env)
 547 {
 548     struct target_rt_sigframe *frame = NULL;
 549     abi_ulong frame_addr = env->xregs[31];
 550
 551     trace_user_do_rt_sigreturn(env, frame_addr);
 552     if (frame_addr & 15) {
 553         goto badframe;
 554     }
 555
 556     if  (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 557         goto badframe;
 558     }
 559
 560     if (target_restore_sigframe(env, frame)) {
 561         goto badframe;
 562     }
 563
 564     if (do_sigaltstack(frame_addr +
 565             offsetof(struct target_rt_sigframe, uc.tuc_stack),
 566             0, get_sp_from_cpustate(env)) == -EFAULT) {
 567         goto badframe;
 568     }
 569
 570     unlock_user_struct(frame, frame_addr, 0);
 571     return -TARGET_QEMU_ESIGRETURN;
 572
 573  badframe:
 574     unlock_user_struct(frame, frame_addr, 0);
 575     force_sig(TARGET_SIGSEGV);
 576     return -TARGET_QEMU_ESIGRETURN;
 577 }
 578
 579 long do_sigreturn(CPUARMState *env)
 580 {
 581     return do_rt_sigreturn(env);
 582 }