getcontextx.c revision 331722 
1/*
2 * Copyright (c) 2011 Konstantin Belousov <kib@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/lib/libc/amd64/gen/getcontextx.c 331722 2018-03-29 02:50:57Z eadler $");
29
30#include <sys/types.h>
31#include <sys/ucontext.h>
32#include <errno.h>
33#include <stdarg.h>
34#include <stdlib.h>
35#include <machine/cpufunc.h>
36#include <machine/fpu.h>
37#include <machine/specialreg.h>
38#include <machine/sysarch.h>
39
40static int xstate_sz = -1;
41
42int
43__getcontextx_size(void)
44{
45	u_int p[4];
46
47	if (xstate_sz == -1) {
48		do_cpuid(1, p);
49		if ((p[2] & CPUID2_OSXSAVE) != 0) {
50			cpuid_count(0xd, 0x0, p);
51			xstate_sz = p[1] - sizeof(struct savefpu);
52		} else
53			xstate_sz = 0;
54	}
55
56	return (sizeof(ucontext_t) + xstate_sz);
57}
58
59int
60__fillcontextx2(char *ctx)
61{
62	struct amd64_get_xfpustate xfpu;
63	ucontext_t *ucp;
64
65	ucp = (ucontext_t *)ctx;
66	if (xstate_sz != 0) {
67		xfpu.addr = (char *)(ucp + 1);
68		xfpu.len = xstate_sz;
69		if (sysarch(AMD64_GET_XFPUSTATE, &xfpu) == -1)
70			return (-1);
71		ucp->uc_mcontext.mc_xfpustate = (__register_t)xfpu.addr;
72		ucp->uc_mcontext.mc_xfpustate_len = xstate_sz;
73		ucp->uc_mcontext.mc_flags |= _MC_HASFPXSTATE;
74	} else {
75		ucp->uc_mcontext.mc_xfpustate = 0;
76		ucp->uc_mcontext.mc_xfpustate_len = 0;
77	}
78	return (0);
79}
80
81int
82__fillcontextx(char *ctx)
83{
84	ucontext_t *ucp;
85
86	ucp = (ucontext_t *)ctx;
87	if (getcontext(ucp) == -1)
88		return (-1);
89	__fillcontextx2(ctx);
90	return (0);
91}
92
93__weak_reference(__getcontextx, getcontextx);
94
95ucontext_t *
96__getcontextx(void)
97{
98	char *ctx;
99	int error;
100
101	ctx = malloc(__getcontextx_size());
102	if (ctx == NULL)
103		return (NULL);
104	if (__fillcontextx(ctx) == -1) {
105		error = errno;
106		free(ctx);
107		errno = error;
108		return (NULL);
109	}
110	return ((ucontext_t *)ctx);
111}
112