Add support for XMM registers in GDB for x86 processors that support

SSE (or its successors).

Reviewed by: marcel, davidxu
MFC After: 2 weeks

gnu/usr.bin/gdb/arch/i386/config.h

@@ -162,7 +162,7 @@
 #define HAVE_PT_GETDBREGS 1
 
 /* Define if <sys/ptrace.h> defines the PT_GETXMMREGS request.  */
-/* #undef HAVE_PT_GETXMMREGS */
+#define HAVE_PT_GETXMMREGS
 
 /* Define if libunwind library is being used.  */
 /* #undef HAVE_LIBUNWIND */

gnu/usr.bin/gdb/libgdb/fbsd-threads.c

@@ -110,10 +110,18 @@ static td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
 					 td_event_msg_t *msg);
 static td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th,
 				      td_thrinfo_t *infop);
+#ifdef PT_GETXMMREGS
+static td_err_e (*td_thr_getxmmregs_p) (const td_thrhandle_t *th,
+					char *regset);
+#endif
 static td_err_e (*td_thr_getfpregs_p) (const td_thrhandle_t *th,
 				       prfpregset_t *regset);
 static td_err_e (*td_thr_getgregs_p) (const td_thrhandle_t *th,
 				      prgregset_t gregs);
+#ifdef PT_GETXMMREGS
+static td_err_e (*td_thr_setxmmregs_p) (const td_thrhandle_t *th,
+					const char *fpregs);
+#endif
 static td_err_e (*td_thr_setfpregs_p) (const td_thrhandle_t *th,
 				       const prfpregset_t *fpregs);
 static td_err_e (*td_thr_setgregs_p) (const td_thrhandle_t *th,
@@ -786,6 +794,9 @@ fbsd_lwp_fetch_registers (int regno)
   gregset_t gregs;
   fpregset_t fpregs;
   lwpid_t lwp;
+#ifdef PT_GETXMMREGS
+  char xmmregs[512];
+#endif
 
   if (!target_has_execution)
     {
@@ -800,10 +811,20 @@ fbsd_lwp_fetch_registers (int regno)
     error ("Cannot get lwp %d registers: %s\n", lwp, safe_strerror (errno));
   supply_gregset (&gregs);
   
-  if (ptrace (PT_GETFPREGS, lwp, (caddr_t) &fpregs, 0) == -1)
-    error ("Cannot get lwp %d registers: %s\n ", lwp, safe_strerror (errno));
-
-  supply_fpregset (&fpregs);
+#ifdef PT_GETXMMREGS
+  if (ptrace (PT_GETXMMREGS, lwp, xmmregs, 0) == 0)
+    {
+      i387_supply_fxsave (current_regcache, -1, xmmregs);
+    }
+  else
+    {
+#endif
+      if (ptrace (PT_GETFPREGS, lwp, (caddr_t) &fpregs, 0) == -1)
+	error ("Cannot get lwp %d registers: %s\n ", lwp, safe_strerror (errno));
+      supply_fpregset (&fpregs);
+#ifdef PT_GETXMMREGS
+    }
+#endif
 }
 
 static void
@@ -813,6 +834,9 @@ fbsd_thread_fetch_registers (int regno)
   prfpregset_t fpregset;
   td_thrhandle_t th;
   td_err_e err;
+#ifdef PT_GETXMMREGS
+  char xmmregs[512];
+#endif
 
   if (!IS_THREAD (inferior_ptid))
     {
@@ -831,15 +855,26 @@ fbsd_thread_fetch_registers (int regno)
     error ("Cannot fetch general-purpose registers for thread %d: Thread ID=%ld, %s",
            pid_to_thread_id (inferior_ptid),
            GET_THREAD (inferior_ptid), thread_db_err_str (err));
-
-  err = td_thr_getfpregs_p (&th, &fpregset);
-  if (err != TD_OK)
-    error ("Cannot get floating-point registers for thread %d: Thread ID=%ld, %s",
-           pid_to_thread_id (inferior_ptid),
-           GET_THREAD (inferior_ptid), thread_db_err_str (err));
+#ifdef PT_GETXMMREGS
+  err = td_thr_getxmmregs_p (&th, xmmregs);
+  if (err == TD_OK)
+    {
+      i387_supply_fxsave (current_regcache, -1, xmmregs);
+    }
+  else
+    {
+#endif
+      err = td_thr_getfpregs_p (&th, &fpregset);
+      if (err != TD_OK)
+	error ("Cannot get floating-point registers for thread %d: Thread ID=%ld, %s",
+	       pid_to_thread_id (inferior_ptid),
+	       GET_THREAD (inferior_ptid), thread_db_err_str (err));
+      supply_fpregset (&fpregset);
+#ifdef PT_GETXMMREGS
+    }
+#endif
 
   supply_gregset (gregset);
-  supply_fpregset (&fpregset);
 }
 
 static void
@@ -848,6 +883,9 @@ fbsd_lwp_store_registers (int regno)
   gregset_t gregs;
   fpregset_t fpregs;
   lwpid_t lwp;
+#ifdef PT_GETXMMREGS
+  char xmmregs[512];
+#endif
 
   /* FIXME, is it possible ? */
   if (!IS_LWP (inferior_ptid))
@@ -865,6 +903,20 @@ fbsd_lwp_store_registers (int regno)
   if (ptrace (PT_SETREGS, lwp, (caddr_t) &gregs, 0) == -1)
       error ("Cannot set lwp %d registers: %s\n", lwp, safe_strerror (errno));
 
+#ifdef PT_GETXMMREGS
+  if (regno != -1)
+    if (ptrace (PT_GETXMMREGS, lwp, xmmregs, 0) == -1)
+      goto noxmm;
+
+  i387_fill_fxsave (xmmregs, regno);
+  if (ptrace (PT_SETXMMREGS, lwp, xmmregs, 0) == -1)
+    goto noxmm;
+
+  return;
+
+noxmm:
+#endif
+
   if (regno != -1)
     if (ptrace (PT_GETFPREGS, lwp, (caddr_t) &fpregs, 0) == -1)
       error ("Cannot get lwp %d float registers: %s\n", lwp,
@@ -883,6 +935,9 @@ fbsd_thread_store_registers (int regno)
   prfpregset_t fpregset;
   td_thrhandle_t th;
   td_err_e err;
+#ifdef PT_GETXMMREGS
+  char xmmregs[512];
+#endif
 
   if (!IS_THREAD (inferior_ptid))
     {
@@ -913,12 +968,22 @@ fbsd_thread_store_registers (int regno)
 
   fill_gregset (gregset, regno);
   fill_fpregset (&fpregset, regno);
+#ifdef PT_GETXMMREGS
+  i387_fill_fxsave (xmmregs, regno);
+#endif
 
   err = td_thr_setgregs_p (&th, gregset);
   if (err != TD_OK)
     error ("Cannot store general-purpose registers for thread %d: Thread ID=%d, %s",
            pid_to_thread_id (inferior_ptid), GET_THREAD (inferior_ptid),
            thread_db_err_str (err));
+
+#ifdef PT_GETXMMREGS
+  err = td_thr_setxmmregs_p (&th, xmmregs);
+  if (err == TD_OK)
+    return;
+#endif
+
   err = td_thr_setfpregs_p (&th, &fpregset);
   if (err != TD_OK)
     error ("Cannot store floating-point registers for thread %d: Thread ID=%d, %s",
@@ -1351,8 +1416,14 @@ thread_db_load (void)
   resolve(td_ta_map_lwp2thr);
   resolve(td_ta_thr_iter);
   resolve(td_thr_get_info);
+#ifdef PT_GETXMMREGS
+  resolve(td_thr_getxmmregs);
+#endif
   resolve(td_thr_getfpregs);
   resolve(td_thr_getgregs);
+#ifdef PT_GETXMMREGS
+  resolve(td_thr_setxmmregs);
+#endif
   resolve(td_thr_setfpregs);
   resolve(td_thr_setgregs);
   resolve(td_thr_sstep);
@@ -1518,6 +1589,35 @@ ps_lsetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
   return PS_OK;
 }
 
+#ifdef PT_GETXMMREGS
+ps_err_e
+ps_lgetxmmregs (struct ps_prochandle *ph, lwpid_t lwpid, char *xmmregs)
+{
+  struct cleanup *old_chain;
+
+  old_chain = save_inferior_ptid ();
+  inferior_ptid = BUILD_LWP (lwpid, PIDGET (inferior_ptid));
+  target_fetch_registers (-1);
+  i387_fill_fxsave (xmmregs, -1);
+  do_cleanups (old_chain);
+  return PS_OK;
+}
+
+ps_err_e
+ps_lsetxmmregs (struct ps_prochandle *ph, lwpid_t lwpid,
+		const char *xmmregs)
+{
+  struct cleanup *old_chain;
+
+  old_chain = save_inferior_ptid ();
+  inferior_ptid = BUILD_LWP (lwpid, PIDGET (inferior_ptid));
+  i387_supply_fxsave (current_regcache, -1, xmmregs);
+  target_store_registers (-1);
+  do_cleanups (old_chain);
+  return PS_OK;
+}
+#endif
+
 ps_err_e
 ps_lstop(struct ps_prochandle *ph, lwpid_t lwpid)
 {

include/proc_service.h

@@ -51,6 +51,10 @@ ps_err_e ps_lgetfpregs(struct ps_prochandle *, lwpid_t, prfpregset_t *);
 ps_err_e ps_lgetregs(struct ps_prochandle *, lwpid_t, prgregset_t);
 ps_err_e ps_lsetfpregs(struct ps_prochandle *, lwpid_t, const prfpregset_t *);
 ps_err_e ps_lsetregs(struct ps_prochandle *, lwpid_t, const prgregset_t);
+#ifdef __i386__
+ps_err_e ps_lgetxmmregs (struct ps_prochandle *, lwpid_t, char *);
+ps_err_e ps_lsetxmmregs (struct ps_prochandle *, lwpid_t, const char *);
+#endif
 ps_err_e ps_lstop(struct ps_prochandle *, lwpid_t);
 ps_err_e ps_pcontinue(struct ps_prochandle *);
 ps_err_e ps_pdmodel(struct ps_prochandle *, int *);

lib/libthread_db/arch/i386/libpthread_md.c

@@ -80,6 +80,20 @@ pt_ucontext_to_fpreg(const ucontext_t *uc, struct fpreg *r)
 	}
 }
 
+void
+pt_fxsave_to_ucontext(const char* r, ucontext_t *uc)
+{
+	if (has_xmm_regs)
+		memcpy(&uc->uc_mcontext.mc_fpstate, r, sizeof(struct savexmm));
+}
+
+void
+pt_ucontext_to_fxsave(const ucontext_t *uc, char *r)
+{
+	if (has_xmm_regs)
+		memcpy(r, &uc->uc_mcontext.mc_fpstate, sizeof(struct savexmm));
+}
+
 void
 pt_md_init(void)
 {

lib/libthread_db/libc_r_db.c

@@ -228,6 +228,14 @@ libc_r_db_thr_get_info(const td_thrhandle_t *th, td_thrinfo_t *ti)
 	return ((err == PS_OK) ? TD_OK : TD_ERR);
 }
 
+#ifdef __i386__
+static td_err_e
+libc_r_db_thr_getxmmregs(const td_thrhandle_t *th, char *fxsave)
+{
+	return (TD_NOFPREGS);
+}
+#endif
+
 static td_err_e
 libc_r_db_thr_getfpregs(const td_thrhandle_t *th, prfpregset_t *r)
 {
@@ -284,6 +292,14 @@ libc_r_db_thr_set_event(const td_thrhandle_t *th, td_thr_events_t *ev)
 	return (0);
 }
 
+#ifdef __i386__
+static td_err_e
+libc_r_db_thr_setxmmregs(const td_thrhandle_t *th, const char *fxsave)
+{
+	return (TD_NOFPREGS);
+}
+#endif
+
 static td_err_e
 libc_r_db_thr_setfpregs(const td_thrhandle_t *th, const prfpregset_t *r)
 {
@@ -324,5 +340,9 @@ struct ta_ops libc_r_db_ops = {
 	.to_thr_set_event       = libc_r_db_thr_set_event,
 	.to_thr_setfpregs       = libc_r_db_thr_setfpregs,
 	.to_thr_setgregs        = libc_r_db_thr_setgregs,
-	.to_thr_validate        = libc_r_db_thr_validate
+	.to_thr_validate        = libc_r_db_thr_validate,
+#ifdef __i386__
+	.to_thr_getxmmregs	= libc_r_db_thr_getxmmregs,
+	.to_thr_setxmmregs	= libc_r_db_thr_setxmmregs,
+#endif
 };

lib/libthread_db/libpthread_db.c

@@ -641,6 +641,51 @@ pt_thr_get_info(const td_thrhandle_t *th, td_thrinfo_t *info)
 	return (0);
 }
 
+#ifdef __i386__
+static td_err_e
+pt_thr_getxmmregs(const td_thrhandle_t *th, char *fxsave)
+{
+	const td_thragent_t *ta = th->th_ta;
+	struct kse_thr_mailbox tmbx;
+	psaddr_t tcb_addr, tmbx_addr, ptr;
+	lwpid_t lwp;
+	int ret;
+
+	return TD_ERR;
+
+	TDBG_FUNC();
+
+	ret = pt_validate(th);
+	if (ret)
+		return (ret);
+
+	if (ta->map[th->th_tid].type == PT_LWP) {
+		ret = ps_lgetxmmregs(ta->ph, ta->map[th->th_tid].lwp, fxsave);
+		return (P2T(ret));
+	}
+
+	ret = ps_pread(ta->ph, ta->map[th->th_tid].thr + ta->thread_off_tcb,
+	               &tcb_addr, sizeof(tcb_addr));
+	if (ret != 0)
+		return (P2T(ret));
+	tmbx_addr = tcb_addr + ta->thread_off_tmbx;
+	ptr = tmbx_addr + offsetof(struct kse_thr_mailbox, tm_lwp);
+	ret = ps_pread(ta->ph, ptr, &lwp, sizeof(lwpid_t));
+	if (ret != 0)
+		return (P2T(ret));
+	if (lwp != 0) {
+		ret = ps_lgetxmmregs(ta->ph, lwp, fxsave);
+		return (P2T(ret));
+	}
+
+	ret = ps_pread(ta->ph, tmbx_addr, &tmbx, sizeof(tmbx));
+	if (ret != 0)
+		return (P2T(ret));
+	pt_ucontext_to_fxsave(&tmbx.tm_context, fxsave);
+	return (0);
+}
+#endif
+
 static td_err_e
 pt_thr_getfpregs(const td_thrhandle_t *th, prfpregset_t *fpregs)
 {
@@ -723,6 +768,57 @@ pt_thr_getgregs(const td_thrhandle_t *th, prgregset_t gregs)
 	return (0);
 }
 
+#ifdef __i386__
+static td_err_e
+pt_thr_setxmmregs(const td_thrhandle_t *th, const char *fxsave)
+{
+	const td_thragent_t *ta = th->th_ta;
+	struct kse_thr_mailbox tmbx;
+	psaddr_t tcb_addr, tmbx_addr, ptr;
+	lwpid_t lwp;
+	int ret;
+
+	return TD_ERR;
+
+	TDBG_FUNC();
+
+	ret = pt_validate(th);
+	if (ret)
+		return (ret);
+
+	if (ta->map[th->th_tid].type == PT_LWP) {
+		ret = ps_lsetxmmregs(ta->ph, ta->map[th->th_tid].lwp, fxsave);
+		return (P2T(ret));
+	}
+
+	ret = ps_pread(ta->ph, ta->map[th->th_tid].thr +
+	                ta->thread_off_tcb,
+                        &tcb_addr, sizeof(tcb_addr));
+	if (ret != 0)
+		return (P2T(ret));
+	tmbx_addr = tcb_addr + ta->thread_off_tmbx;
+	ptr = tmbx_addr + offsetof(struct kse_thr_mailbox, tm_lwp);
+	ret = ps_pread(ta->ph, ptr, &lwp, sizeof(lwpid_t));
+	if (ret != 0)
+		return (P2T(ret));
+	if (lwp != 0) {
+		ret = ps_lsetxmmregs(ta->ph, lwp, fxsave);
+		return (P2T(ret));
+	}
+	/*
+	 * Read a copy of context, this makes sure that registers
+	 * not covered by structure reg won't be clobbered
+	 */
+	ret = ps_pread(ta->ph, tmbx_addr, &tmbx, sizeof(tmbx));
+	if (ret != 0)
+		return (P2T(ret));
+
+	pt_fxsave_to_ucontext(fxsave, &tmbx.tm_context);
+	ret = ps_pwrite(ta->ph, tmbx_addr, &tmbx, sizeof(tmbx));
+	return (P2T(ret));
+}
+#endif
+
 static td_err_e
 pt_thr_setfpregs(const td_thrhandle_t *th, const prfpregset_t *fpregs)
 {
@@ -1009,4 +1105,8 @@ struct ta_ops libpthread_db_ops = {
 
 	/* FreeBSD specific extensions. */
 	.to_thr_sstep		= pt_thr_sstep,
+#ifdef __i386__
+	.to_thr_getxmmregs	= pt_thr_getxmmregs,
+	.to_thr_setxmmregs	= pt_thr_setxmmregs,
+#endif
 };

lib/libthread_db/libpthread_db.h

@@ -82,6 +82,10 @@ void pt_reg_to_ucontext(const struct reg *, ucontext_t *);
 void pt_ucontext_to_reg(const ucontext_t *, struct reg *);
 void pt_fpreg_to_ucontext(const struct fpreg *, ucontext_t *);
 void pt_ucontext_to_fpreg(const ucontext_t *, struct fpreg *);
+#ifdef __i386__
+void pt_fxsave_to_ucontext(const char *, ucontext_t *);
+void pt_ucontext_to_fxsave(const ucontext_t *, char *);
+#endif
 int  pt_reg_sstep(struct reg *reg, int step);
 
 #endif /* _LIBPTHREAD_DB_H_ */

lib/libthread_db/libthr_db.c

@@ -505,6 +505,24 @@ pt_thr_get_info(const td_thrhandle_t *th, td_thrinfo_t *info)
 	return (0);
 }
 
+#ifdef __i386__
+static td_err_e
+pt_thr_getxmmregs(const td_thrhandle_t *th, char *fxsave)
+{
+	const td_thragent_t *ta = th->th_ta;
+	int ret;
+
+	TDBG_FUNC();
+
+	ret = pt_validate(th);
+	if (ret)
+		return (ret);
+
+	ret = ps_lgetxmmregs(ta->ph, th->th_tid, fxsave);
+	return (P2T(ret));
+}
+#endif
+
 static td_err_e
 pt_thr_getfpregs(const td_thrhandle_t *th, prfpregset_t *fpregs)
 {
@@ -537,6 +555,24 @@ pt_thr_getgregs(const td_thrhandle_t *th, prgregset_t gregs)
 	return (P2T(ret));
 }
 
+#ifdef __i386__
+static td_err_e
+pt_thr_setxmmregs(const td_thrhandle_t *th, const char *fxsave)
+{
+	const td_thragent_t *ta = th->th_ta;
+	int ret;
+
+	TDBG_FUNC();
+
+	ret = pt_validate(th);
+	if (ret)
+		return (ret);
+
+	ret = ps_lsetxmmregs(ta->ph, th->th_tid, fxsave);
+	return (P2T(ret));
+}
+#endif
+
 static td_err_e
 pt_thr_setfpregs(const td_thrhandle_t *th, const prfpregset_t *fpregs)
 {
@@ -742,4 +778,8 @@ struct ta_ops libthr_db_ops = {
 
 	/* FreeBSD specific extensions. */
 	.to_thr_sstep		= pt_thr_sstep,
+#ifdef __i386__
+	.to_thr_getxmmregs	= pt_thr_getxmmregs,
+	.to_thr_setxmmregs	= pt_thr_setxmmregs,
+#endif
 };

lib/libthread_db/thread_db.c

@@ -184,6 +184,16 @@ td_thr_get_info(const td_thrhandle_t *th, td_thrinfo_t *info)
 	return (ta->ta_ops->to_thr_get_info(th, info));
 }
 
+#ifdef __i386__
+td_err_e
+td_thr_getxmmregs(const td_thrhandle_t *th, char *fxsave)
+{
+	const td_thragent_t *ta = th->th_ta;
+	return (ta->ta_ops->to_thr_getxmmregs(th, fxsave));
+}
+#endif
+
+
 td_err_e
 td_thr_getfpregs(const td_thrhandle_t *th, prfpregset_t *fpregset)
 {
@@ -205,6 +215,15 @@ td_thr_set_event(const td_thrhandle_t *th, td_thr_events_t *events)
 	return (ta->ta_ops->to_thr_set_event(th, events));
 }
 
+#ifdef __i386__
+td_err_e
+td_thr_setxmmregs(const td_thrhandle_t *th, const char *fxsave)
+{
+	const td_thragent_t *ta = th->th_ta;
+	return (ta->ta_ops->to_thr_setxmmregs(th, fxsave));
+}
+#endif
+
 td_err_e
 td_thr_setfpregs(const td_thrhandle_t *th, const prfpregset_t *fpregs)
 {

lib/libthread_db/thread_db.h

@@ -227,9 +227,15 @@ td_err_e td_thr_dbsuspend(const td_thrhandle_t *);
 td_err_e td_thr_event_enable(const td_thrhandle_t *, int);
 td_err_e td_thr_event_getmsg(const td_thrhandle_t *, td_event_msg_t *);
 td_err_e td_thr_get_info(const td_thrhandle_t *, td_thrinfo_t *);
+#ifdef __i386__
+td_err_e td_thr_getxmmregs(const td_thrhandle_t *, char *);
+#endif
 td_err_e td_thr_getfpregs(const td_thrhandle_t *, prfpregset_t *);
 td_err_e td_thr_getgregs(const td_thrhandle_t *, prgregset_t);
 td_err_e td_thr_set_event(const td_thrhandle_t *, td_thr_events_t *);
+#ifdef __i386__
+td_err_e td_thr_setxmmregs(const td_thrhandle_t *, const char *);
+#endif
 td_err_e td_thr_setfpregs(const td_thrhandle_t *, const prfpregset_t *);
 td_err_e td_thr_setgregs(const td_thrhandle_t *, const prgregset_t);
 td_err_e td_thr_validate(const td_thrhandle_t *);

lib/libthread_db/thread_db_int.h

@@ -79,6 +79,10 @@ struct ta_ops {
 
 	/* FreeBSD specific extensions. */
 	td_err_e (*to_thr_sstep)(const td_thrhandle_t *, int);
+#if defined(__i386__)
+	td_err_e (*to_thr_getxmmregs)(const td_thrhandle_t *, char *);
+	td_err_e (*to_thr_setxmmregs)(const td_thrhandle_t *, const char *);
+#endif
 };
 
 #ifdef TD_DEBUG

sys/conf/files.i386

@@ -293,6 +293,7 @@ i386/i386/nexus.c		standard
 i386/i386/perfmon.c		optional perfmon
 i386/i386/perfmon.c		optional perfmon	profiling-routine
 i386/i386/pmap.c		standard
+i386/i386/ptrace_machdep.c	standard
 i386/i386/support.s		standard
 i386/i386/swtch.s		standard
 i386/i386/sys_machdep.c		standard

sys/i386/i386/ptrace_machdep.c

@@ -0,0 +1,62 @@
+/*-
+ * Copyright (c) 2005 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/ptrace.h>
+#include <machine/md_var.h>
+#include <machine/pcb.h>
+
+int
+cpu_ptrace(struct thread *td, int req, void *addr, int data)
+{
+	int error;
+
+	if (!cpu_fxsr)
+		return (EINVAL);
+
+	switch (req) {
+	case PT_GETXMMREGS:
+		error = copyout(&td->td_pcb->pcb_save.sv_xmm, addr,
+		    sizeof(td->td_pcb->pcb_save.sv_xmm));
+		break;
+
+	case PT_SETXMMREGS:
+		error = copyin(addr, &td->td_pcb->pcb_save.sv_xmm,
+		    sizeof(td->td_pcb->pcb_save.sv_xmm));
+		break;
+
+	default:
+		return (EINVAL);
+	}
+
+	return (error);
+}

sys/i386/include/ptrace.h

@@ -33,4 +33,9 @@
 #ifndef _MACHINE_PTRACE_H_
 #define _MACHINE_PTRACE_H_
 
+#define	__HAVE_PTRACE_MACHDEP
+
+#define PT_GETXMMREGS	(PT_FIRSTMACH + 0)
+#define PT_SETXMMREGS	(PT_FIRSTMACH + 1)
+
 #endif

sys/i386/include/reg.h

@@ -114,6 +114,18 @@ struct fpreg {
 	unsigned char	fpr_pad[64];
 };
 
+struct xmmreg {
+	/*
+	 * XXX should get struct from npx.h.  Here we give a slightly
+	 * simplified struct.  This may be too much detail.  Perhaps
+	 * an array of unsigned longs is best.
+	 */
+	unsigned long	xmm_env[8];
+	unsigned char	xmm_acc[8][16];
+	unsigned char	xmm_reg[8][16];
+	unsigned char	xmm_pad[224];
+};
+
 /*
  * Register set accessible via /proc/$pid/dbregs.
  */