15254 %ymm registers not restored after signal handler
15367 x86 getfpregs() summons corrupting %xmm ghosts
15333 want x86 /proc xregs support (libc_db, libproc, mdb, etc.)
15336 want libc functions for extended ucontext_t
15334 want ps_lwphandle-specific reg routines
15328 FPU_CW_INIT mistreats reserved bit
15335 i86pc fpu_subr.c isn't really platform-specific
15332 setcontext(2) isn't actually noreturn
15331 need <sys/stdalign.h>
Change-Id: I7060aa86042dfb989f77fc3323c065ea2eafa9ad
Conflicts:
    usr/src/uts/common/fs/proc/prcontrol.c
    usr/src/uts/intel/os/archdep.c
    usr/src/uts/intel/sys/ucontext.h
    usr/src/uts/intel/syscall/getcontext.c

          --- old/usr/src/lib/libc/amd64/gen/siglongjmp.c
          +++ new/usr/src/lib/libc/amd64/gen/siglongjmp.c

   1    1  /*
   2    2   * CDDL HEADER START
   3    3   *
   4    4   * The contents of this file are subject to the terms of the
   5    5   * Common Development and Distribution License (the "License").
   6    6   * You may not use this file except in compliance with the License.
   7    7   *
   8    8   * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9    9   * or http://www.opensolaris.org/os/licensing.
  10   10   * See the License for the specific language governing permissions
  11   11   * and limitations under the License.
  12   12   *
  13   13   * When distributing Covered Code, include this CDDL HEADER in each
  14   14   * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15   15   * If applicable, add the following below this CDDL HEADER, with the
  16   16   * fields enclosed by brackets "[]" replaced with your own identifying

  17   17   * information: Portions Copyright [yyyy] [name of copyright owner]
  18   18   *
  19   19   * CDDL HEADER END
  20   20   */
  21   21  
  22   22  /*
  23   23   * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24   24   * Use is subject to license terms.
  25   25   */
  26   26  
       27 +/*
       28 + * Copyright 2023 Oxide Computer Company
       29 + */
       30 +
  27   31  #include "lint.h"
  28   32  #include <sys/types.h>
  29   33  #include <sys/ucontext.h>
  30   34  #include <setjmp.h>
  31   35  #include <ucontext.h>
       36 +#include <strings.h>
       37 +#include <upanic.h>
  32   38  #include "sigjmp_struct.h"
  33   39  #include "libc.h"
  34   40  
  35   41  #pragma weak _siglongjmp = siglongjmp
  36   42  
  37   43  void
  38   44  siglongjmp(sigjmp_buf env, int val)
  39   45  {
       46 +        const char *msg = "siglongjmp(): setcontext() returned";
  40   47          ucontext_t *ucp = SIGJMP2UCONTEXT(env);
  41   48  
  42   49          if (val)
  43   50                  ucp->uc_mcontext.gregs[REG_R0] = val;
  44   51          else
  45   52                  ucp->uc_mcontext.gregs[REG_R0] = 1;
  46   53  
       54 +        /*
       55 +         * While unlikely, it is possible that setcontext() may fail for some
       56 +         * reason. If that happens, we will kill the process.
       57 +         */
  47   58          (void) setcontext(ucp);
       59 +        upanic(msg, strlen(msg) + 1);
  48   60  }
    

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX