xref: /freebsd/sys/i386/acpica/acpi_wakecode.S (revision ca987d4641cdcd7f27e153db17c5bf064934faf5)
1/*-
2 * Copyright (c) 2001 Takanori Watanabe <takawata@jp.freebsd.org>
3 * Copyright (c) 2001-2012 Mitsuru IWASAKI <iwasaki@jp.freebsd.org>
4 * Copyright (c) 2003 Peter Wemm
5 * Copyright (c) 2008-2012 Jung-uk Kim <jkim@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32#include <machine/asmacros.h>
33#include <machine/ppireg.h>
34#include <machine/specialreg.h>
35#include <machine/timerreg.h>
36
37#include "assym.s"
38
39/*
40 * Resume entry point.  The BIOS enters here in real mode after POST with
41 * CS set to the page where we stored this code.  It should configure the
42 * segment registers with a flat 4 GB address space and EFLAGS.IF = 0.
43 * Depending on the previous sleep state, we may need to initialize more
44 * of the system (i.e., S3 suspend-to-RAM vs. S4 suspend-to-disk).
45 */
46
47	.data				/* So we can modify it */
48
49	ALIGN_TEXT
50	.code16
51wakeup_start:
52	/*
53	 * Set up segment registers for real mode, a small stack for
54	 * any calls we make, and clear any flags.
55	 */
56	cli				/* make sure no interrupts */
57	mov	%cs, %ax		/* copy %cs to %ds.  Remember these */
58	mov	%ax, %ds		/* are offsets rather than selectors */
59	mov	%ax, %ss
60	movw	$PAGE_SIZE, %sp
61	xorw	%ax, %ax
62	pushw	%ax
63	popfw
64
65	/* To debug resume hangs, beep the speaker if the user requested. */
66	testb	$~0, resume_beep - wakeup_start
67	jz	1f
68	movb	$0, resume_beep - wakeup_start
69
70	/* Set PIC timer2 to beep. */
71	movb	$(TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT), %al
72	outb	%al, $TIMER_MODE
73
74	/* Turn on speaker. */
75	inb	$IO_PPI, %al
76	orb	$PIT_SPKR, %al
77	outb	%al, $IO_PPI
78
79	/* Set frequency. */
80	movw	$0x4c0, %ax
81	outb	%al, $TIMER_CNTR2
82	shrw	$8, %ax
83	outb	%al, $TIMER_CNTR2
841:
85
86	/* Re-initialize video BIOS if the reset_video tunable is set. */
87	testb	$~0, reset_video - wakeup_start
88	jz	1f
89	movb	$0, reset_video - wakeup_start
90	lcall	$0xc000, $3
91
92	/* When we reach here, int 0x10 should be ready.  Hide cursor. */
93	movb	$0x01, %ah
94	movb	$0x20, %ch
95	int	$0x10
96
97	/* Re-start in case the previous BIOS call clobbers them. */
98	jmp	wakeup_start
991:
100
101	/*
102	 * Find relocation base and patch the gdt descript and ljmp targets
103	 */
104	xorl	%ebx, %ebx
105	mov	%cs, %bx
106	sall	$4, %ebx		/* %ebx is now our relocation base */
107
108	/*
109	 * Load the descriptor table pointer.  We'll need it when running
110	 * in 16-bit protected mode.
111	 */
112	lgdtl	bootgdtdesc - wakeup_start
113
114	/* Enable protected mode */
115	movl	$CR0_PE, %eax
116	mov	%eax, %cr0
117
118	/*
119	 * Now execute a far jump to turn on protected mode.  This
120	 * causes the segment registers to turn into selectors and causes
121	 * %cs to be loaded from the gdt.
122	 *
123	 * The following instruction is:
124	 * ljmpl $bootcode32 - bootgdt, $wakeup_32 - wakeup_start
125	 * but gas cannot assemble that.  And besides, we patch the targets
126	 * in early startup and its a little clearer what we are patching.
127	 */
128wakeup_sw32:
129	.byte	0x66			/* size override to 32 bits */
130	.byte	0xea			/* opcode for far jump */
131	.long	wakeup_32 - wakeup_start /* offset in segment */
132	.word	bootcode32 - bootgdt	/* index in gdt for 32 bit code */
133
134	/*
135	 * At this point, we are running in 32 bit legacy protected mode.
136	 */
137	ALIGN_TEXT
138	.code32
139wakeup_32:
140
141	mov	$bootdata32 - bootgdt, %eax
142	mov	%ax, %ds
143
144	/* Get PCB and return address. */
145	movl	wakeup_pcb - wakeup_start(%ebx), %ecx
146	movl	wakeup_ret - wakeup_start(%ebx), %edx
147
148	/* Restore CR4 and CR3. */
149	movl	wakeup_cr4 - wakeup_start(%ebx), %eax
150	mov	%eax, %cr4
151	movl	wakeup_cr3 - wakeup_start(%ebx), %eax
152	mov	%eax, %cr3
153
154	/* Enable paging. */
155	mov	%cr0, %eax
156	orl	$CR0_PG, %eax
157	mov	%eax, %cr0
158
159	jmp	1f
1601:
161	/* Jump to return address. */
162	jmp	*%edx
163
164	.data
165
166resume_beep:
167	.byte	0
168reset_video:
169	.byte	0
170
171	ALIGN_DATA
172bootgdt:
173	.long	0x00000000
174	.long	0x00000000
175
176bootcode32:
177	.long	0x0000ffff
178	.long	0x00cf9b00
179
180bootdata32:
181	.long	0x0000ffff
182	.long	0x00cf9300
183bootgdtend:
184
185bootgdtdesc:
186	.word	bootgdtend - bootgdt	/* Length */
187	.long	bootgdt - wakeup_start	/* Offset plus %ds << 4 */
188
189	ALIGN_DATA
190wakeup_cr4:
191	.long	0
192wakeup_cr3:
193	.long	0
194wakeup_pcb:
195	.long	0
196wakeup_ret:
197	.long	0
198wakeup_gdt:		/* not used */
199	.word	0
200	.long	0
201dummy:
202