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

*** 26,36 ****
   * Copyright 2012 DEY Storage Systems, Inc.  All rights reserved.
   * Copyright (c) 2018, Joyent, Inc. All rights reserved.
   * Copyright (c) 2013 by Delphix. All rights reserved.
   * Copyright 2015 Gary Mills
   * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
!  * Copyright 2021 Oxide Computer Company
   */
  
  #include <sys/types.h>
  #include <sys/utsname.h>
  #include <sys/sysmacros.h>
--- 26,36 ----
   * Copyright 2012 DEY Storage Systems, Inc.  All rights reserved.
   * Copyright (c) 2018, Joyent, Inc. All rights reserved.
   * Copyright (c) 2013 by Delphix. All rights reserved.
   * Copyright 2015 Gary Mills
   * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
!  * Copyright 2023 Oxide Computer Company
   */
  
  #include <sys/types.h>
  #include <sys/utsname.h>
  #include <sys/sysmacros.h>
*** 1079,1113 ****
          P->nauxv = (int)n;
  
          return (0);
  }
  
! #ifdef __sparc
  static int
  note_xreg(struct ps_prochandle *P, size_t nbytes)
  {
          core_info_t *core = P->data;
          lwp_info_t *lwp = core->core_lwp;
-         size_t xbytes = sizeof (prxregset_t);
          prxregset_t *xregs;
  
!         if (lwp == NULL || lwp->lwp_xregs != NULL || nbytes < xbytes)
                  return (0);     /* No lwp yet, already seen, or bad size */
  
!         if ((xregs = malloc(xbytes)) == NULL)
                  return (-1);
  
!         if (read(P->asfd, xregs, xbytes) != xbytes) {
                  dprintf("Pgrab_core: failed to read NT_PRXREG\n");
                  free(xregs);
                  return (-1);
          }
  
          lwp->lwp_xregs = xregs;
          return (0);
  }
  
  static int
  note_gwindows(struct ps_prochandle *P, size_t nbytes)
  {
          core_info_t *core = P->data;
          lwp_info_t *lwp = core->core_lwp;
--- 1079,1123 ----
          P->nauxv = (int)n;
  
          return (0);
  }
  
! /*
!  * The xregs are not a fixed size on all architectures (notably x86) and in
!  * general the prxregset_t has become opaque to deal with this. This means that
!  * validating the note itself can be a little more challenging. Especially as
!  * this can change across time. In this case we require that our consumers
!  * perform this validation right now ala what mdb does before using the xregs
!  * data.
!  */
  static int
  note_xreg(struct ps_prochandle *P, size_t nbytes)
  {
          core_info_t *core = P->data;
          lwp_info_t *lwp = core->core_lwp;
          prxregset_t *xregs;
+         ssize_t sret;
  
!         if (lwp == NULL || lwp->lwp_xregs != NULL)
                  return (0);     /* No lwp yet, already seen, or bad size */
  
!         if ((xregs = malloc(nbytes)) == NULL)
                  return (-1);
  
!         sret = read(P->asfd, xregs, nbytes);
!         if (sret < 0 || (size_t)sret != nbytes) {
                  dprintf("Pgrab_core: failed to read NT_PRXREG\n");
                  free(xregs);
                  return (-1);
          }
  
          lwp->lwp_xregs = xregs;
+         lwp->lwp_xregsize = nbytes;
          return (0);
  }
  
+ #ifdef __sparc
  static int
  note_gwindows(struct ps_prochandle *P, size_t nbytes)
  {
          core_info_t *core = P->data;
          lwp_info_t *lwp = core->core_lwp;
*** 1252,1266 ****
  #ifdef __x86
          note_linux_psinfo,              /*  3   NT_PRPSINFO (old)       */
  #else
          note_notsup,            /*  3   NT_PRPSINFO (old)       */
  #endif
- #ifdef __sparc
          note_xreg,              /*  4   NT_PRXREG               */
- #else
-         note_notsup,            /*  4   NT_PRXREG               */
- #endif
          note_platform,          /*  5   NT_PLATFORM             */
          note_auxv,              /*  6   NT_AUXV                 */
  #ifdef __sparc
          note_gwindows,          /*  7   NT_GWINDOWS             */
  #ifdef __sparcv9
--- 1262,1272 ----