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

*** 22,31 ****
--- 22,32 ----
  /*        All Rights Reserved   */
  
  
  /*
   * Copyright 2014 Garrett D'Amore <garrett@damore.org>
+  * Copyright 2023 Oxide Computer Company
   *
   * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
*** 45,54 ****
--- 46,56 ----
   * does NOT include sys/regset.h anymore.
   */
  #if !defined(_XPG4_2) || defined(__EXTENSIONS__)
  #include <sys/regset.h>
  #include <sys/siginfo.h>
+ #include <sys/int_types.h>
  #endif
  
  #ifdef  __cplusplus
  extern "C" {
  #endif
*** 61,76 ****
  #endif
  #endif
  
  extern int getcontext(ucontext_t *) __RETURNS_TWICE;
  #pragma unknown_control_flow(getcontext)
! extern int setcontext(const ucontext_t *) __NORETURN;
  extern int swapcontext(ucontext_t *_RESTRICT_KYWD,
                  const ucontext_t *_RESTRICT_KYWD);
  extern void makecontext(ucontext_t *, void(*)(), int, ...);
  
  #if !defined(_XPG4_2) || defined(__EXTENSIONS__)
  extern int walkcontext(const ucontext_t *, int (*)(uintptr_t, int, void *),
      void *);
  extern int printstack(int);
  extern int addrtosymstr(void *, char *, int);
  extern int getustack(stack_t **);
--- 63,84 ----
  #endif
  #endif
  
  extern int getcontext(ucontext_t *) __RETURNS_TWICE;
  #pragma unknown_control_flow(getcontext)
! extern int setcontext(const ucontext_t *);
  extern int swapcontext(ucontext_t *_RESTRICT_KYWD,
                  const ucontext_t *_RESTRICT_KYWD);
  extern void makecontext(ucontext_t *, void(*)(), int, ...);
  
  #if !defined(_XPG4_2) || defined(__EXTENSIONS__)
+ extern ucontext_t *ucontext_alloc(uint32_t);
+ extern void ucontext_free(ucontext_t *);
+ extern int getcontext_extd(ucontext_t *, uint32_t) __RETURNS_TWICE;
+ #pragma unknown_control_flow(getcontext_extd)
+ extern int swapcontext_extd(ucontext_t *_RESTRICT_KYWD, uint32_t,
+                 const ucontext_t *_RESTRICT_KYWD);
  extern int walkcontext(const ucontext_t *, int (*)(uintptr_t, int, void *),
      void *);
  extern int printstack(int);
  extern int addrtosymstr(void *, char *, int);
  extern int getustack(stack_t **);