xref: /freebsd/sys/i386/acpica/acpi_wakecode.S (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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.inc"
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 and a small stack for
54	 * any calls we make.  Set up full 32-bit bootstrap kernel flags
55	 * since resumectx() doesn't restore flags.  PSL_KERNEL gives
56	 * bootstrap kernel flags (with interrupts disabled), not normal
57	 * kernel flags.
58	 */
59	cli				/* make sure no interrupts */
60	mov	%cs, %ax		/* copy %cs to %ds.  Remember these */
61	mov	%ax, %ds		/* are offsets rather than selectors */
62	mov	%ax, %ss
63	movw	$PAGE_SIZE, %sp
64	pushl	$PSL_KERNEL
65	popfl
66
67	/* To debug resume hangs, beep the speaker if the user requested. */
68	testb	$~0, resume_beep - wakeup_start
69	jz	1f
70	movb	$0, resume_beep - wakeup_start
71
72	/* Set PIC timer2 to beep. */
73	movb	$(TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT), %al
74	outb	%al, $TIMER_MODE
75
76	/* Turn on speaker. */
77	inb	$IO_PPI, %al
78	orb	$PIT_SPKR, %al
79	outb	%al, $IO_PPI
80
81	/* Set frequency. */
82	movw	$0x4c0, %ax
83	outb	%al, $TIMER_CNTR2
84	shrw	$8, %ax
85	outb	%al, $TIMER_CNTR2
861:
87
88	/* Re-initialize video BIOS if the reset_video tunable is set. */
89	testb	$~0, reset_video - wakeup_start
90	jz	1f
91	movb	$0, reset_video - wakeup_start
92	lcall	$0xc000, $3
93
94	/* When we reach here, int 0x10 should be ready.  Hide cursor. */
95	movb	$0x01, %ah
96	movb	$0x20, %ch
97	int	$0x10
98
99	/* Re-start in case the previous BIOS call clobbers them. */
100	jmp	wakeup_start
1011:
102
103	/*
104	 * Find relocation base and patch the gdt descript and ljmp targets
105	 */
106	xorl	%ebx, %ebx
107	mov	%cs, %bx
108	sall	$4, %ebx		/* %ebx is now our relocation base */
109
110	/*
111	 * Load the descriptor table pointer.  We'll need it when running
112	 * in 16-bit protected mode.
113	 */
114	lgdtl	bootgdtdesc - wakeup_start
115
116	/* Enable protected mode */
117	movl	$CR0_PE, %eax
118	mov	%eax, %cr0
119
120	/*
121	 * Now execute a far jump to turn on protected mode.  This
122	 * causes the segment registers to turn into selectors and causes
123	 * %cs to be loaded from the gdt.
124	 *
125	 * The following instruction is:
126	 * ljmpl $bootcode32 - bootgdt, $wakeup_32 - wakeup_start
127	 * but gas cannot assemble that.  And besides, we patch the targets
128	 * in early startup and its a little clearer what we are patching.
129	 */
130wakeup_sw32:
131	.byte	0x66			/* size override to 32 bits */
132	.byte	0xea			/* opcode for far jump */
133	.long	wakeup_32 - wakeup_start /* offset in segment */
134	.word	bootcode32 - bootgdt	/* index in gdt for 32 bit code */
135
136	/*
137	 * At this point, we are running in 32 bit legacy protected mode.
138	 */
139	ALIGN_TEXT
140	.code32
141wakeup_32:
142
143	mov	$bootdata32 - bootgdt, %eax
144	mov	%ax, %ds
145
146	/* Restore EFER, CR4 and CR3. */
147	movl	wakeup_efer - wakeup_start(%ebx), %eax
148	movl	wakeup_efer - wakeup_start + 4(%ebx), %edx
149	cmpl	$0, %eax
150	jne	1f
151	cmpl	$0, %edx
152	je	2f
1531:	movl	$MSR_EFER, %ecx
154	wrmsr
1552:	movl	wakeup_cr4 - wakeup_start(%ebx), %eax
156	cmpl	$0, %eax
157	je	3f
158	mov	%eax, %cr4
1593:	movl	wakeup_cr3 - wakeup_start(%ebx), %eax
160	mov	%eax, %cr3
161
162	/* Get PCB and return address. */
163	movl	wakeup_ret - wakeup_start(%ebx), %edx
164	movl	wakeup_pcb - wakeup_start(%ebx), %ecx
165
166	/* Enable paging. */
167	mov	%cr0, %eax
168	orl	$CR0_PG, %eax
169	mov	%eax, %cr0
170
171	/* Jump to return address. */
172	jmp	*%edx
173
174	.data
175
176resume_beep:
177	.byte	0
178reset_video:
179	.byte	0
180
181	ALIGN_DATA
182bootgdt:
183	.long	0x00000000
184	.long	0x00000000
185
186bootcode32:
187	.long	0x0000ffff
188	.long	0x00cf9b00
189
190bootdata32:
191	.long	0x0000ffff
192	.long	0x00cf9300
193bootgdtend:
194
195bootgdtdesc:
196	.word	bootgdtend - bootgdt	/* Length */
197	.long	bootgdt - wakeup_start	/* Offset plus %ds << 4 */
198
199	ALIGN_DATA
200wakeup_efer:
201	.long	0
202	.long	0
203wakeup_cr4:
204	.long	0
205wakeup_cr3:
206	.long	0
207wakeup_pcb:
208	.long	0
209wakeup_ret:
210	.long	0
211wakeup_gdt:		/* not used */
212	.word	0
213	.long	0
214dummy:
215