1/*-
2 * Copyright (c) 2003 Peter Wemm
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 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/11/sys/amd64/ia32/ia32_sigtramp.S 331839 2018-03-31 12:43:07Z kib $
27 */
28
29#include "opt_compat.h"
30
31#include <machine/asmacros.h>
32#include <sys/syscall.h>
33
34#include "ia32_assym.h"
35
36	.text
37	.code32
38/*
39 * Signal trampoline, copied to top of user stack
40 * XXX may need to be MD to match backend sendsig handoff protocol
41 */
42	ALIGN_TEXT
43	.globl	ia32_sigcode
44ia32_sigcode:
45	calll	*IA32_SIGF_HANDLER(%esp)
46	leal	IA32_SIGF_UC(%esp),%eax	/* get ucontext */
47	pushl	%eax
48	movl	$SYS_sigreturn,%eax
49	pushl	%eax			/* junk to fake return addr. */
50	int	$0x80			/* enter kernel with args */
51					/* on stack */
521:
53	jmp	1b
54
55#ifdef COMPAT_FREEBSD4
56	ALIGN_TEXT
57freebsd4_ia32_sigcode:
58	calll	*IA32_SIGF_HANDLER(%esp)
59	leal	IA32_SIGF_UC4(%esp),%eax/* get ucontext */
60	pushl	%eax
61	movl	$344,%eax		/* 4.x SYS_sigreturn */
62	pushl	%eax			/* junk to fake return addr. */
63	int	$0x80			/* enter kernel with args */
64					/* on stack */
651:
66	jmp	1b
67#endif
68
69#ifdef COMPAT_43
70	ALIGN_TEXT
71ia32_osigcode:
72	calll	*IA32_SIGF_HANDLER(%esp)/* call signal handler */
73	leal	IA32_SIGF_SC(%esp),%eax	/* get sigcontext */
74	pushl	%eax
75	movl	$103,%eax		/* 3.x SYS_sigreturn */
76	pushl	%eax			/* junk to fake return addr. */
77	int	$0x80			/* enter kernel with args */
781:
79	jmp	1b
80
81/*
82 * Our lcall $7,$0 handler remains in user mode (ring 3), since lcalls
83 * don't change the interrupt mask, so if this one went directly to the
84 * kernel then there would be a window with interrupts enabled in kernel
85 * mode, and all interrupt handlers would have to be almost as complicated
86 * as the NMI handler to support this.
87 *
88 * Instead, convert the lcall to an int0x80 call.  The kernel does most
89 * of the conversion by popping the lcall return values off the user
90 * stack and returning to them instead of to here, except when the
91 * conversion itself fails.  Adjusting the stack here is impossible for
92 * vfork() and harder for other syscalls.
93 */
94	ALIGN_TEXT
95lcall_tramp:
96	int	$0x80
971:	jmp	1b
98#endif
99
100	ALIGN_TEXT
101esigcode:
102
103	.data
104	.globl	sz_ia32_sigcode
105sz_ia32_sigcode:
106	.long	esigcode-ia32_sigcode
107#ifdef COMPAT_FREEBSD4
108	.globl	sz_freebsd4_ia32_sigcode
109sz_freebsd4_ia32_sigcode:
110	.long	esigcode-freebsd4_ia32_sigcode
111#endif
112#ifdef COMPAT_43
113	.globl	sz_ia32_osigcode
114sz_ia32_osigcode:
115	.long	esigcode-ia32_osigcode
116	.globl	sz_lcall_tramp
117sz_lcall_tramp:
118	.long	esigcode-lcall_tramp
119#endif
120