sys/arm64/arm64/exec_machdep.c

   1 /*-
   2  * Copyright (c) 2014 Andrew Turner
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/exec.h>
  34 #include <sys/imgact.h>
  35 #include <sys/kdb.h>
  36 #include <sys/kernel.h>
  37 #include <sys/ktr.h>
  38 #include <sys/limits.h>
  39 #include <sys/lock.h>
  40 #include <sys/mutex.h>
  41 #include <sys/proc.h>
  42 #include <sys/ptrace.h>
  43 #include <sys/reg.h>
  44 #include <sys/rwlock.h>
  45 #include <sys/signalvar.h>
  46 #include <sys/syscallsubr.h>
  47 #include <sys/sysent.h>
  48 #include <sys/sysproto.h>
  49 #include <sys/ucontext.h>
  50
  51 #include <vm/vm.h>
  52 #include <vm/vm_param.h>
  53
  54 #include <machine/armreg.h>
  55 #include <machine/kdb.h>
  56 #include <machine/md_var.h>
  57 #include <machine/pcb.h>
  58
  59 #ifdef VFP
  60 #include <machine/vfp.h>
  61 #endif
  62
  63 _Static_assert(sizeof(mcontext_t) == 880, "mcontext_t size incorrect");
  64 _Static_assert(sizeof(ucontext_t) == 960, "ucontext_t size incorrect");
  65 _Static_assert(sizeof(siginfo_t) == 80, "siginfo_t size incorrect");
  66
  67 static void get_fpcontext(struct thread *td, mcontext_t *mcp);
  68 static void set_fpcontext(struct thread *td, mcontext_t *mcp);
  69
  70 int
  71 fill_regs(struct thread *td, struct reg *regs)
  72 {
  73         struct trapframe *frame;
  74
  75         frame = td->td_frame;
  76         regs->sp = frame->tf_sp;
  77         regs->lr = frame->tf_lr;
  78         regs->elr = frame->tf_elr;
  79         regs->spsr = frame->tf_spsr;
  80
  81         memcpy(regs->x, frame->tf_x, sizeof(regs->x));
  82
  83 #ifdef COMPAT_FREEBSD32
  84         /*
  85          * We may be called here for a 32bits process, if we're using a
  86          * 64bits debugger. If so, put PC and SPSR where it expects it.
  87          */
  88         if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
  89                 regs->x[15] = frame->tf_elr;
  90                 regs->x[16] = frame->tf_spsr;
  91         }
  92 #endif
  93         return (0);
  94 }
  95
  96 int
  97 set_regs(struct thread *td, struct reg *regs)
  98 {
  99         struct trapframe *frame;
 100
 101         frame = td->td_frame;
 102         frame->tf_sp = regs->sp;
 103         frame->tf_lr = regs->lr;
 104
 105         memcpy(frame->tf_x, regs->x, sizeof(frame->tf_x));
 106
 107 #ifdef COMPAT_FREEBSD32
 108         if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
 109                 /*
 110                  * We may be called for a 32bits process if we're using
 111                  * a 64bits debugger. If so, get PC and SPSR from where
 112                  * it put it.
 113                  */
 114                 frame->tf_elr = regs->x[15];
 115                 frame->tf_spsr &= ~PSR_SETTABLE_32;
 116                 frame->tf_spsr |= regs->x[16] & PSR_SETTABLE_32;
 117                 /* Don't allow userspace to ask to continue single stepping.
 118                  * The SPSR.SS field doesn't exist when the EL1 is AArch32.
 119                  * As the SPSR.DIT field has moved in its place don't
 120                  * allow userspace to set the SPSR.SS field.
 121                  */
 122         } else
 123 #endif
 124         {
 125                 frame->tf_elr = regs->elr;
 126                 frame->tf_spsr &= ~PSR_SETTABLE_64;
 127                 frame->tf_spsr |= regs->spsr & PSR_SETTABLE_64;
 128                 /* Enable single stepping if userspace asked fot it */
 129                 if ((frame->tf_spsr & PSR_SS) != 0) {
 130                         td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
 131
 132                         WRITE_SPECIALREG(mdscr_el1,
 133                             READ_SPECIALREG(mdscr_el1) | MDSCR_SS);
 134                         isb();
 135                 }
 136         }
 137         return (0);
 138 }
 139
 140 int
 141 fill_fpregs(struct thread *td, struct fpreg *regs)
 142 {
 143 #ifdef VFP
 144         struct pcb *pcb;
 145
 146         pcb = td->td_pcb;
 147         if ((pcb->pcb_fpflags & PCB_FP_STARTED) != 0) {
 148                 /*
 149                  * If we have just been running VFP instructions we will
 150                  * need to save the state to memcpy it below.
 151                  */
 152                 if (td == curthread)
 153                         vfp_save_state(td, pcb);
 154
 155                 KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
 156                     ("Called fill_fpregs while the kernel is using the VFP"));
 157                 memcpy(regs->fp_q, pcb->pcb_fpustate.vfp_regs,
 158                     sizeof(regs->fp_q));
 159                 regs->fp_cr = pcb->pcb_fpustate.vfp_fpcr;
 160                 regs->fp_sr = pcb->pcb_fpustate.vfp_fpsr;
 161         } else
 162 #endif
 163                 memset(regs, 0, sizeof(*regs));
 164         return (0);
 165 }
 166
 167 int
 168 set_fpregs(struct thread *td, struct fpreg *regs)
 169 {
 170 #ifdef VFP
 171         struct pcb *pcb;
 172
 173         pcb = td->td_pcb;
 174         KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
 175             ("Called set_fpregs while the kernel is using the VFP"));
 176         memcpy(pcb->pcb_fpustate.vfp_regs, regs->fp_q, sizeof(regs->fp_q));
 177         pcb->pcb_fpustate.vfp_fpcr = regs->fp_cr;
 178         pcb->pcb_fpustate.vfp_fpsr = regs->fp_sr;
 179 #endif
 180         return (0);
 181 }
 182
 183 int
 184 fill_dbregs(struct thread *td, struct dbreg *regs)
 185 {
 186         struct debug_monitor_state *monitor;
 187         int i;
 188         uint8_t debug_ver, nbkpts, nwtpts;
 189
 190         memset(regs, 0, sizeof(*regs));
 191
 192         extract_user_id_field(ID_AA64DFR0_EL1, ID_AA64DFR0_DebugVer_SHIFT,
 193             &debug_ver);
 194         extract_user_id_field(ID_AA64DFR0_EL1, ID_AA64DFR0_BRPs_SHIFT,
 195             &nbkpts);
 196         extract_user_id_field(ID_AA64DFR0_EL1, ID_AA64DFR0_WRPs_SHIFT,
 197             &nwtpts);
 198
 199         /*
 200          * The BRPs field contains the number of breakpoints - 1. Armv8-A
 201          * allows the hardware to provide 2-16 breakpoints so this won't
 202          * overflow an 8 bit value. The same applies to the WRPs field.
 203          */
 204         nbkpts++;
 205         nwtpts++;
 206
 207         regs->db_debug_ver = debug_ver;
 208         regs->db_nbkpts = nbkpts;
 209         regs->db_nwtpts = nwtpts;
 210
 211         monitor = &td->td_pcb->pcb_dbg_regs;
 212         if ((monitor->dbg_flags & DBGMON_ENABLED) != 0) {
 213                 for (i = 0; i < nbkpts; i++) {
 214                         regs->db_breakregs[i].dbr_addr = monitor->dbg_bvr[i];
 215                         regs->db_breakregs[i].dbr_ctrl = monitor->dbg_bcr[i];
 216                 }
 217                 for (i = 0; i < nwtpts; i++) {
 218                         regs->db_watchregs[i].dbw_addr = monitor->dbg_wvr[i];
 219                         regs->db_watchregs[i].dbw_ctrl = monitor->dbg_wcr[i];
 220                 }
 221         }
 222
 223         return (0);
 224 }
 225
 226 int
 227 set_dbregs(struct thread *td, struct dbreg *regs)
 228 {
 229         struct debug_monitor_state *monitor;
 230         uint64_t addr;
 231         uint32_t ctrl;
 232         int i;
 233
 234         monitor = &td->td_pcb->pcb_dbg_regs;
 235         monitor->dbg_enable_count = 0;
 236
 237         for (i = 0; i < DBG_BRP_MAX; i++) {
 238                 addr = regs->db_breakregs[i].dbr_addr;
 239                 ctrl = regs->db_breakregs[i].dbr_ctrl;
 240
 241                 /*
 242                  * Don't let the user set a breakpoint on a kernel or
 243                  * non-canonical user address.
 244                  */
 245                 if (addr >= VM_MAXUSER_ADDRESS)
 246                         return (EINVAL);
 247
 248                 /*
 249                  * The lowest 2 bits are ignored, so record the effective
 250                  * address.
 251                  */
 252                 addr = rounddown2(addr, 4);
 253
 254                 /*
 255                  * Some control fields are ignored, and other bits reserved.
 256                  * Only unlinked, address-matching breakpoints are supported.
 257                  *
 258                  * XXX: fields that appear unvalidated, such as BAS, have
 259                  * constrained undefined behaviour. If the user mis-programs
 260                  * these, there is no risk to the system.
 261                  */
 262                 ctrl &= DBGBCR_EN | DBGBCR_PMC | DBGBCR_BAS;
 263                 if ((ctrl & DBGBCR_EN) != 0) {
 264                         /* Only target EL0. */
 265                         if ((ctrl & DBGBCR_PMC) != DBGBCR_PMC_EL0)
 266                                 return (EINVAL);
 267
 268                         monitor->dbg_enable_count++;
 269                 }
 270
 271                 monitor->dbg_bvr[i] = addr;
 272                 monitor->dbg_bcr[i] = ctrl;
 273         }
 274
 275         for (i = 0; i < DBG_WRP_MAX; i++) {
 276                 addr = regs->db_watchregs[i].dbw_addr;
 277                 ctrl = regs->db_watchregs[i].dbw_ctrl;
 278
 279                 /*
 280                  * Don't let the user set a watchpoint on a kernel or
 281                  * non-canonical user address.
 282                  */
 283                 if (addr >= VM_MAXUSER_ADDRESS)
 284                         return (EINVAL);
 285
 286                 /*
 287                  * Some control fields are ignored, and other bits reserved.
 288                  * Only unlinked watchpoints are supported.
 289                  */
 290                 ctrl &= DBGWCR_EN | DBGWCR_PAC | DBGWCR_LSC | DBGWCR_BAS |
 291                     DBGWCR_MASK;
 292
 293                 if ((ctrl & DBGWCR_EN) != 0) {
 294                         /* Only target EL0. */
 295                         if ((ctrl & DBGWCR_PAC) != DBGWCR_PAC_EL0)
 296                                 return (EINVAL);
 297
 298                         /* Must set at least one of the load/store bits. */
 299                         if ((ctrl & DBGWCR_LSC) == 0)
 300                                 return (EINVAL);
 301
 302                         /*
 303                          * When specifying the address range with BAS, the MASK
 304                          * field must be zero.
 305                          */
 306                         if ((ctrl & DBGWCR_BAS) != DBGWCR_BAS &&
 307                             (ctrl & DBGWCR_MASK) != 0)
 308                                 return (EINVAL);
 309
 310                         monitor->dbg_enable_count++;
 311                 }
 312                 monitor->dbg_wvr[i] = addr;
 313                 monitor->dbg_wcr[i] = ctrl;
 314         }
 315
 316         if (monitor->dbg_enable_count > 0)
 317                 monitor->dbg_flags |= DBGMON_ENABLED;
 318
 319         return (0);
 320 }
 321
 322 #ifdef COMPAT_FREEBSD32
 323 int
 324 fill_regs32(struct thread *td, struct reg32 *regs)
 325 {
 326         int i;
 327         struct trapframe *tf;
 328
 329         tf = td->td_frame;
 330         for (i = 0; i < 13; i++)
 331                 regs->r[i] = tf->tf_x[i];
 332         /* For arm32, SP is r13 and LR is r14 */
 333         regs->r_sp = tf->tf_x[13];
 334         regs->r_lr = tf->tf_x[14];
 335         regs->r_pc = tf->tf_elr;
 336         regs->r_cpsr = tf->tf_spsr;
 337
 338         return (0);
 339 }
 340
 341 int
 342 set_regs32(struct thread *td, struct reg32 *regs)
 343 {
 344         int i;
 345         struct trapframe *tf;
 346
 347         tf = td->td_frame;
 348         for (i = 0; i < 13; i++)
 349                 tf->tf_x[i] = regs->r[i];
 350         /* For arm 32, SP is r13 an LR is r14 */
 351         tf->tf_x[13] = regs->r_sp;
 352         tf->tf_x[14] = regs->r_lr;
 353         tf->tf_elr = regs->r_pc;
 354         tf->tf_spsr &= ~PSR_SETTABLE_32;
 355         tf->tf_spsr |= regs->r_cpsr & PSR_SETTABLE_32;
 356
 357         return (0);
 358 }
 359
 360 /* XXX fill/set dbregs/fpregs are stubbed on 32-bit arm. */
 361 int
 362 fill_fpregs32(struct thread *td, struct fpreg32 *regs)
 363 {
 364
 365         memset(regs, 0, sizeof(*regs));
 366         return (0);
 367 }
 368
 369 int
 370 set_fpregs32(struct thread *td, struct fpreg32 *regs)
 371 {
 372
 373         return (0);
 374 }
 375
 376 int
 377 fill_dbregs32(struct thread *td, struct dbreg32 *regs)
 378 {
 379
 380         memset(regs, 0, sizeof(*regs));
 381         return (0);
 382 }
 383
 384 int
 385 set_dbregs32(struct thread *td, struct dbreg32 *regs)
 386 {
 387
 388         return (0);
 389 }
 390 #endif
 391
 392 void
 393 exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
 394 {
 395         struct trapframe *tf = td->td_frame;
 396         struct pcb *pcb = td->td_pcb;
 397
 398         memset(tf, 0, sizeof(struct trapframe));
 399
 400         tf->tf_x[0] = stack;
 401         tf->tf_sp = STACKALIGN(stack);
 402         tf->tf_lr = imgp->entry_addr;
 403         tf->tf_elr = imgp->entry_addr;
 404
 405         td->td_pcb->pcb_tpidr_el0 = 0;
 406         td->td_pcb->pcb_tpidrro_el0 = 0;
 407         WRITE_SPECIALREG(tpidrro_el0, 0);
 408         WRITE_SPECIALREG(tpidr_el0, 0);
 409
 410 #ifdef VFP
 411         vfp_reset_state(td, pcb);
 412 #endif
 413
 414         /*
 415          * Clear debug register state. It is not applicable to the new process.
 416          */
 417         bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
 418
 419         /* Generate new pointer authentication keys */
 420         ptrauth_exec(td);
 421 }
 422
 423 /* Sanity check these are the same size, they will be memcpy'd to and from */
 424 CTASSERT(sizeof(((struct trapframe *)0)->tf_x) ==
 425     sizeof((struct gpregs *)0)->gp_x);
 426 CTASSERT(sizeof(((struct trapframe *)0)->tf_x) ==
 427     sizeof((struct reg *)0)->x);
 428
 429 int
 430 get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 431 {
 432         struct trapframe *tf = td->td_frame;
 433
 434         if (clear_ret & GET_MC_CLEAR_RET) {
 435                 mcp->mc_gpregs.gp_x[0] = 0;
 436                 mcp->mc_gpregs.gp_spsr = tf->tf_spsr & ~PSR_C;
 437         } else {
 438                 mcp->mc_gpregs.gp_x[0] = tf->tf_x[0];
 439                 mcp->mc_gpregs.gp_spsr = tf->tf_spsr;
 440         }
 441
 442         memcpy(&mcp->mc_gpregs.gp_x[1], &tf->tf_x[1],
 443             sizeof(mcp->mc_gpregs.gp_x[1]) * (nitems(mcp->mc_gpregs.gp_x) - 1));
 444
 445         mcp->mc_gpregs.gp_sp = tf->tf_sp;
 446         mcp->mc_gpregs.gp_lr = tf->tf_lr;
 447         mcp->mc_gpregs.gp_elr = tf->tf_elr;
 448         get_fpcontext(td, mcp);
 449
 450         return (0);
 451 }
 452
 453 int
 454 set_mcontext(struct thread *td, mcontext_t *mcp)
 455 {
 456         struct trapframe *tf = td->td_frame;
 457         uint32_t spsr;
 458
 459         spsr = mcp->mc_gpregs.gp_spsr;
 460         if ((spsr & PSR_M_MASK) != PSR_M_EL0t ||
 461             (spsr & PSR_AARCH32) != 0 ||
 462             (spsr & PSR_DAIF) != (td->td_frame->tf_spsr & PSR_DAIF))
 463                 return (EINVAL);
 464
 465         memcpy(tf->tf_x, mcp->mc_gpregs.gp_x, sizeof(tf->tf_x));
 466
 467         tf->tf_sp = mcp->mc_gpregs.gp_sp;
 468         tf->tf_lr = mcp->mc_gpregs.gp_lr;
 469         tf->tf_elr = mcp->mc_gpregs.gp_elr;
 470         tf->tf_spsr = mcp->mc_gpregs.gp_spsr;
 471         if ((tf->tf_spsr & PSR_SS) != 0) {
 472                 td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
 473
 474                 WRITE_SPECIALREG(mdscr_el1,
 475                     READ_SPECIALREG(mdscr_el1) | MDSCR_SS);
 476                 isb();
 477         }
 478         set_fpcontext(td, mcp);
 479
 480         return (0);
 481 }
 482
 483 static void
 484 get_fpcontext(struct thread *td, mcontext_t *mcp)
 485 {
 486 #ifdef VFP
 487         struct pcb *curpcb;
 488
 489         critical_enter();
 490
 491         curpcb = curthread->td_pcb;
 492
 493         if ((curpcb->pcb_fpflags & PCB_FP_STARTED) != 0) {
 494                 /*
 495                  * If we have just been running VFP instructions we will
 496                  * need to save the state to memcpy it below.
 497                  */
 498                 vfp_save_state(td, curpcb);
 499
 500                 KASSERT(curpcb->pcb_fpusaved == &curpcb->pcb_fpustate,
 501                     ("Called get_fpcontext while the kernel is using the VFP"));
 502                 KASSERT((curpcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
 503                     ("Non-userspace FPU flags set in get_fpcontext"));
 504                 memcpy(mcp->mc_fpregs.fp_q, curpcb->pcb_fpustate.vfp_regs,
 505                     sizeof(mcp->mc_fpregs.fp_q));
 506                 mcp->mc_fpregs.fp_cr = curpcb->pcb_fpustate.vfp_fpcr;
 507                 mcp->mc_fpregs.fp_sr = curpcb->pcb_fpustate.vfp_fpsr;
 508                 mcp->mc_fpregs.fp_flags = curpcb->pcb_fpflags;
 509                 mcp->mc_flags |= _MC_FP_VALID;
 510         }
 511
 512         critical_exit();
 513 #endif
 514 }
 515
 516 static void
 517 set_fpcontext(struct thread *td, mcontext_t *mcp)
 518 {
 519 #ifdef VFP
 520         struct pcb *curpcb;
 521
 522         critical_enter();
 523
 524         if ((mcp->mc_flags & _MC_FP_VALID) != 0) {
 525                 curpcb = curthread->td_pcb;
 526
 527                 /*
 528                  * Discard any vfp state for the current thread, we
 529                  * are about to override it.
 530                  */
 531                 vfp_discard(td);
 532
 533                 KASSERT(curpcb->pcb_fpusaved == &curpcb->pcb_fpustate,
 534                     ("Called set_fpcontext while the kernel is using the VFP"));
 535                 memcpy(curpcb->pcb_fpustate.vfp_regs, mcp->mc_fpregs.fp_q,
 536                     sizeof(mcp->mc_fpregs.fp_q));
 537                 curpcb->pcb_fpustate.vfp_fpcr = mcp->mc_fpregs.fp_cr;
 538                 curpcb->pcb_fpustate.vfp_fpsr = mcp->mc_fpregs.fp_sr;
 539                 curpcb->pcb_fpflags = mcp->mc_fpregs.fp_flags & PCB_FP_USERMASK;
 540         }
 541
 542         critical_exit();
 543 #endif
 544 }
 545
 546 int
 547 sys_sigreturn(struct thread *td, struct sigreturn_args *uap)
 548 {
 549         ucontext_t uc;
 550         int error;
 551
 552         if (copyin(uap->sigcntxp, &uc, sizeof(uc)))
 553                 return (EFAULT);
 554
 555         error = set_mcontext(td, &uc.uc_mcontext);
 556         if (error != 0)
 557                 return (error);
 558
 559         /* Restore signal mask. */
 560         kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
 561
 562         return (EJUSTRETURN);
 563 }
 564
 565 void
 566 sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 567 {
 568         struct thread *td;
 569         struct proc *p;
 570         struct trapframe *tf;
 571         struct sigframe *fp, frame;
 572         struct sigacts *psp;
 573         int onstack, sig;
 574
 575         td = curthread;
 576         p = td->td_proc;
 577         PROC_LOCK_ASSERT(p, MA_OWNED);
 578
 579         sig = ksi->ksi_signo;
 580         psp = p->p_sigacts;
 581         mtx_assert(&psp->ps_mtx, MA_OWNED);
 582
 583         tf = td->td_frame;
 584         onstack = sigonstack(tf->tf_sp);
 585
 586         CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
 587             catcher, sig);
 588
 589         /* Allocate and validate space for the signal handler context. */
 590         if ((td->td_pflags & TDP_ALTSTACK) != 0 && !onstack &&
 591             SIGISMEMBER(psp->ps_sigonstack, sig)) {
 592                 fp = (struct sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
 593                     td->td_sigstk.ss_size);
 594 #if defined(COMPAT_43)
 595                 td->td_sigstk.ss_flags |= SS_ONSTACK;
 596 #endif
 597         } else {
 598                 fp = (struct sigframe *)td->td_frame->tf_sp;
 599         }
 600
 601         /* Make room, keeping the stack aligned */
 602         fp--;
 603         fp = (struct sigframe *)STACKALIGN(fp);
 604
 605         /* Fill in the frame to copy out */
 606         bzero(&frame, sizeof(frame));
 607         get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
 608         frame.sf_si = ksi->ksi_info;
 609         frame.sf_uc.uc_sigmask = *mask;
 610         frame.sf_uc.uc_stack = td->td_sigstk;
 611         frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) != 0 ?
 612             (onstack ? SS_ONSTACK : 0) : SS_DISABLE;
 613         mtx_unlock(&psp->ps_mtx);
 614         PROC_UNLOCK(td->td_proc);
 615
 616         /* Copy the sigframe out to the user's stack. */
 617         if (copyout(&frame, fp, sizeof(*fp)) != 0) {
 618                 /* Process has trashed its stack. Kill it. */
 619                 CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
 620                 PROC_LOCK(p);
 621                 sigexit(td, SIGILL);
 622         }
 623
 624         tf->tf_x[0] = sig;
 625         tf->tf_x[1] = (register_t)&fp->sf_si;
 626         tf->tf_x[2] = (register_t)&fp->sf_uc;
 627         tf->tf_x[8] = (register_t)catcher;
 628         tf->tf_sp = (register_t)fp;
 629         tf->tf_elr = (register_t)p->p_sysent->sv_sigcode_base;
 630
 631         /* Clear the single step flag while in the signal handler */
 632         if ((td->td_pcb->pcb_flags & PCB_SINGLE_STEP) != 0) {
 633                 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
 634                 WRITE_SPECIALREG(mdscr_el1,
 635                     READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
 636                 isb();
 637         }
 638
 639         CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_elr,
 640             tf->tf_sp);
 641
 642         PROC_LOCK(p);
 643         mtx_lock(&psp->ps_mtx);
 644 }