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

@@ -26,11 +26,11 @@
 /*
  * Copyright 2012 DEY Storage Systems, Inc.  All rights reserved.
  * Copyright 2018 Joyent, Inc.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
- * Copyright 2021 Oxide Computer Company
+ * Copyright 2023 Oxide Computer Company
  */
 
 #define _STRUCTURED_PROC        1
 
 #include <assert.h>

@@ -441,20 +441,10 @@
                     sizeof (prfpregset32_t), pgc->pgc_doff) != 0)
                         return (1);
 #endif  /* _LP64 */
         }
 
-#ifdef sparc
-        {
-                prxregset_t xregs;
-                if (Plwp_getxregs(P, lsp->pr_lwpid, &xregs) == 0 &&
-                    write_note(pgc->pgc_fd, NT_PRXREG, &xregs,
-                    sizeof (prxregset_t), pgc->pgc_doff) != 0)
-                        return (1);
-        }
-#endif  /* sparc */
-
         return (0);
 }
 
 static int
 new_per_lwp(void *data, const lwpstatus_t *lsp, const lwpsinfo_t *lip)

@@ -493,44 +483,29 @@
                     sizeof (lwpstatus32_t), pgc->pgc_doff) != 0)
                         return (1);
 #endif  /* _LP64 */
         }
 
-#ifdef sparc
         {
-                prxregset_t xregs;
-                gwindows_t gwins;
+                prxregset_t *xregs;
                 size_t size;
 
-                if (Plwp_getxregs(P, lsp->pr_lwpid, &xregs) == 0) {
-                        if (write_note(pgc->pgc_fd, NT_PRXREG, &xregs,
-                            sizeof (prxregset_t), pgc->pgc_doff) != 0)
-                                return (1);
-                }
-
-                if (Plwp_getgwindows(P, lsp->pr_lwpid, &gwins) == 0 &&
-                    gwins.wbcnt > 0) {
-                        size = sizeof (gwins) - sizeof (gwins.wbuf) +
-                            gwins.wbcnt * sizeof (gwins.wbuf[0]);
-
-                        if (write_note(pgc->pgc_fd, NT_GWINDOWS, &gwins, size,
+                /*
+                 * While historically this function was only present on some
+                 * architectures (despite the presence of the empty file
+                 * elsewhere), if we call this on a platform without support
+                 * it'll now fail and thus is no longer subject to
+                 * platform-specific ifdefs.
+                 */
+                if (Plwp_getxregs(P, lsp->pr_lwpid, &xregs, &size) == 0) {
+                        if (write_note(pgc->pgc_fd, NT_PRXREG, xregs, size,
                             pgc->pgc_doff) != 0)
                                 return (1);
-                }
 
+                        Plwp_freexregs(P, xregs, size);
         }
-#ifdef __sparcv9
-        if (P->status.pr_dmodel == PR_MODEL_LP64) {
-                asrset_t asrs;
-                if (Plwp_getasrs(P, lsp->pr_lwpid, asrs) == 0) {
-                        if (write_note(pgc->pgc_fd, NT_ASRS, &asrs,
-                            sizeof (asrset_t), pgc->pgc_doff) != 0)
-                                return (1);
                 }
-        }
-#endif  /* __sparcv9 */
-#endif  /* sparc */
 
         if (Plwp_getname(P, lsp->pr_lwpid, name.pr_lwpname,
             sizeof (name.pr_lwpname)) == 0) {
                 name.pr_lwpid = lsp->pr_lwpid;
                 if (write_note(pgc->pgc_fd, NT_LWPNAME, &name,