xref: /freebsd/stand/efi/loader/arch/amd64/amd64_tramp.S (revision ca987d4641cdcd7f27e153db17c5bf064934faf5)
1*ca987d46SWarner Losh/*-
2*ca987d46SWarner Losh * Copyright (c) 2013 The FreeBSD Foundation
3*ca987d46SWarner Losh * All rights reserved.
4*ca987d46SWarner Losh *
5*ca987d46SWarner Losh * This software was developed by Benno Rice under sponsorship from
6*ca987d46SWarner Losh * the FreeBSD Foundation.
7*ca987d46SWarner Losh * Redistribution and use in source and binary forms, with or without
8*ca987d46SWarner Losh * modification, are permitted provided that the following conditions
9*ca987d46SWarner Losh * are met:
10*ca987d46SWarner Losh * 1. Redistributions of source code must retain the above copyright
11*ca987d46SWarner Losh *    notice, this list of conditions and the following disclaimer.
12*ca987d46SWarner Losh * 2. Redistributions in binary form must reproduce the above copyright
13*ca987d46SWarner Losh *    notice, this list of conditions and the following disclaimer in the
14*ca987d46SWarner Losh *    documentation and/or other materials provided with the distribution.
15*ca987d46SWarner Losh *
16*ca987d46SWarner Losh * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17*ca987d46SWarner Losh * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18*ca987d46SWarner Losh * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19*ca987d46SWarner Losh * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20*ca987d46SWarner Losh * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21*ca987d46SWarner Losh * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22*ca987d46SWarner Losh * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23*ca987d46SWarner Losh * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24*ca987d46SWarner Losh * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25*ca987d46SWarner Losh * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26*ca987d46SWarner Losh * SUCH DAMAGE.
27*ca987d46SWarner Losh *
28*ca987d46SWarner Losh * $FreeBSD$
29*ca987d46SWarner Losh */
30*ca987d46SWarner Losh
31*ca987d46SWarner Losh#include <machine/asmacros.h>
32*ca987d46SWarner Losh
33*ca987d46SWarner Losh	.text
34*ca987d46SWarner Losh	.globl	amd64_tramp
35*ca987d46SWarner Losh
36*ca987d46SWarner Losh/*
37*ca987d46SWarner Losh * void amd64_tramp(uint64_t stack, void *copy_finish, uint64_t kernend,
38*ca987d46SWarner Losh *		    uint64_t modulep, uint64_t pagetable, uint64_t entry)
39*ca987d46SWarner Losh */
40*ca987d46SWarner Loshamd64_tramp:
41*ca987d46SWarner Losh	cli			/* Make sure we don't get interrupted. */
42*ca987d46SWarner Losh	movq	%rdi,%rsp	/* Switch to our temporary stack. */
43*ca987d46SWarner Losh
44*ca987d46SWarner Losh	movq	%rdx,%r12	/* Stash the kernel values for later. */
45*ca987d46SWarner Losh	movq	%rcx,%r13
46*ca987d46SWarner Losh	movq	%r8,%r14
47*ca987d46SWarner Losh	movq	%r9,%r15
48*ca987d46SWarner Losh
49*ca987d46SWarner Losh	callq	*%rsi		/* Call copy_finish so we're all ready to go. */
50*ca987d46SWarner Losh
51*ca987d46SWarner Losh	pushq	%r12		/* Push kernend. */
52*ca987d46SWarner Losh	salq	$32,%r13	/* Shift modulep and push it. */
53*ca987d46SWarner Losh	pushq	%r13
54*ca987d46SWarner Losh	pushq	%r15		/* Push the entry address. */
55*ca987d46SWarner Losh	movq	%r14,%cr3	/* Switch page tables. */
56*ca987d46SWarner Losh	ret			/* "Return" to kernel entry. */
57*ca987d46SWarner Losh
58*ca987d46SWarner Losh	ALIGN_TEXT
59*ca987d46SWarner Loshamd64_tramp_end:
60*ca987d46SWarner Losh
61*ca987d46SWarner Losh	.data
62*ca987d46SWarner Losh	.globl	amd64_tramp_size
63*ca987d46SWarner Loshamd64_tramp_size:
64*ca987d46SWarner Losh	.long	amd64_tramp_end-amd64_tramp
65