1/*-
2 * Copyright (c) 2001 Takanori Watanabe <takawata@jp.freebsd.org>
3 * Copyright (c) 2001 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: stable/11/sys/amd64/acpica/acpi_wakecode.S 319133 2017-05-29 13:17:00Z kib $
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 for real mode.
41 *
42 * If XFirmwareWakingVector is zero and FirmwareWakingVector is non-zero
43 * in FACS, the BIOS enters here in real mode after POST with CS set to
44 * (FirmwareWakingVector >> 4) and IP set to (FirmwareWakingVector & 0xf).
45 * Depending on the previous sleep state, we may need to initialize more
46 * of the system (i.e., S3 suspend-to-RAM vs. S4 suspend-to-disk).
47 *
48 * Note: If XFirmwareWakingVector is non-zero, it should disable address
49 * translation/paging and interrupts, load all segment registers with
50 * a flat 4 GB address space, and set EFLAGS.IF to zero.  Currently
51 * this mode is not supported by this code.
52 */
53
54	.data				/* So we can modify it */
55
56	ALIGN_TEXT
57	.code16
58wakeup_start:
59	/*
60	 * Set up segment registers for real mode, a small stack for
61	 * any calls we make, and clear any flags.
62	 */
63	cli				/* make sure no interrupts */
64	mov	%cs, %ax		/* copy %cs to %ds.  Remember these */
65	mov	%ax, %ds		/* are offsets rather than selectors */
66	mov	%ax, %ss
67	movw	$PAGE_SIZE, %sp
68	xorw	%ax, %ax
69	pushw	%ax
70	popfw
71
72	/* To debug resume hangs, beep the speaker if the user requested. */
73	testb	$~0, resume_beep - wakeup_start
74	jz	1f
75	movb	$0, resume_beep - wakeup_start
76
77	/* Set PIC timer2 to beep. */
78	movb	$(TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT), %al
79	outb	%al, $TIMER_MODE
80
81	/* Turn on speaker. */
82	inb	$IO_PPI, %al
83	orb	$PIT_SPKR, %al
84	outb	%al, $IO_PPI
85
86	/* Set frequency. */
87	movw	$0x4c0, %ax
88	outb	%al, $TIMER_CNTR2
89	shrw	$8, %ax
90	outb	%al, $TIMER_CNTR2
911:
92
93	/* Re-initialize video BIOS if the reset_video tunable is set. */
94	testb	$~0, reset_video - wakeup_start
95	jz	1f
96	movb	$0, reset_video - wakeup_start
97	lcall	$0xc000, $3
98
99	/* When we reach here, int 0x10 should be ready.  Hide cursor. */
100	movb	$0x01, %ah
101	movb	$0x20, %ch
102	int	$0x10
103
104	/* Re-start in case the previous BIOS call clobbers them. */
105	jmp	wakeup_start
1061:
107
108	/*
109	 * Find relocation base and patch the gdt descript and ljmp targets
110	 */
111	xorl	%ebx, %ebx
112	mov	%cs, %bx
113	sall	$4, %ebx		/* %ebx is now our relocation base */
114
115	/*
116	 * Load the descriptor table pointer.  We'll need it when running
117	 * in 16-bit protected mode.
118	 */
119	lgdtl	bootgdtdesc - wakeup_start
120
121	/* Enable protected mode */
122	movl	$CR0_PE, %eax
123	mov	%eax, %cr0
124
125	/*
126	 * Now execute a far jump to turn on protected mode.  This
127	 * causes the segment registers to turn into selectors and causes
128	 * %cs to be loaded from the gdt.
129	 *
130	 * The following instruction is:
131	 * ljmpl $bootcode32 - bootgdt, $wakeup_32 - wakeup_start
132	 * but gas cannot assemble that.  And besides, we patch the targets
133	 * in early startup and its a little clearer what we are patching.
134	 */
135wakeup_sw32:
136	.byte	0x66			/* size override to 32 bits */
137	.byte	0xea			/* opcode for far jump */
138	.long	wakeup_32 - wakeup_start /* offset in segment */
139	.word	bootcode32 - bootgdt	/* index in gdt for 32 bit code */
140
141	/*
142	 * At this point, we are running in 32 bit legacy protected mode.
143	 */
144	ALIGN_TEXT
145	.code32
146wakeup_32:
147
148	mov	$bootdata32 - bootgdt, %eax
149	mov	%ax, %ds
150
151	/* Turn on the PAE bit for when paging is enabled */
152	mov	%cr4, %eax
153	orl	$CR4_PAE, %eax
154	mov	%eax, %cr4
155
156	/*
157	 * Enable EFER.LME so that we get long mode when all the prereqs are
158	 * in place.  In this case, it turns on when CR0_PG is finally enabled.
159	 * Also it picks up a few other EFER bits that we'll use need we're
160	 * here, like SYSCALL and NX enable.
161	 */
162	movl	$MSR_EFER, %ecx
163	movl	wakeup_efer - wakeup_start(%ebx), %eax
164	movl	wakeup_efer + 4 - wakeup_start(%ebx), %edx
165	wrmsr
166
167	/*
168	 * Point to the embedded page tables for startup.  Note that this
169	 * only gets accessed after we're actually in 64 bit mode, however
170	 * we can only set the bottom 32 bits of %cr3 in this state.  This
171	 * means we are required to use a temporary page table that is below
172	 * the 4GB limit.  %ebx is still our relocation base.  We could just
173	 * subtract 3 * PAGE_SIZE, but that would be too easy.
174	 */
175	leal	wakeup_pagetables - wakeup_start(%ebx), %eax
176	movl	(%eax), %eax
177	mov	%eax, %cr3
178
179	/*
180	 * Finally, switch to long bit mode by enabling paging.  We have
181	 * to be very careful here because all the segmentation disappears
182	 * out from underneath us.  The spec says we can depend on the
183	 * subsequent pipelined branch to execute, but *only if* everything
184	 * is still identity mapped.  If any mappings change, the pipeline
185	 * will flush.
186	 */
187	mov	%cr0, %eax
188	orl	$CR0_PG, %eax
189	mov	%eax, %cr0
190
191	/*
192	 * At this point paging is enabled, and we are in "compatibility" mode.
193	 * We do another far jump to reload %cs with the 64 bit selector.
194	 * %cr3 points to a 4-level page table page.
195	 * We cannot yet jump all the way to the kernel because we can only
196	 * specify a 32 bit linear address.  So, yet another trampoline.
197	 *
198	 * The following instruction is:
199	 * ljmp $bootcode64 - bootgdt, $wakeup_64 - wakeup_start
200	 * but gas cannot assemble that.  And besides, we patch the targets
201	 * in early startup and its a little clearer what we are patching.
202	 */
203wakeup_sw64:
204	.byte	0xea			/* opcode for far jump */
205	.long	wakeup_64 - wakeup_start /* offset in segment */
206	.word	bootcode64 - bootgdt	/* index in gdt for 64 bit code */
207
208	/*
209	 * Yeehar!  We're running in 64-bit mode!  We can mostly ignore our
210	 * segment registers, and get on with it.
211	 * Note that we are running at the correct virtual address, but with
212	 * a 1:1 1GB mirrored mapping over entire address space.  We had better
213	 * switch to a real %cr3 promptly so that we can get to the direct map
214	 * space. Remember that jmp is relative and that we've been relocated,
215	 * so use an indirect jump.
216	 */
217	ALIGN_TEXT
218	.code64
219wakeup_64:
220	mov	$bootdata64 - bootgdt, %eax
221	mov	%ax, %ds
222
223	/* Restore arguments. */
224	movq	wakeup_pcb - wakeup_start(%rbx), %rdi
225	movq	wakeup_ret - wakeup_start(%rbx), %rax
226
227	/* Restore GDT. */
228	lgdt	wakeup_gdt - wakeup_start(%rbx)
229
230	/* Jump to return address. */
231	jmp	*%rax
232
233	.data
234
235resume_beep:
236	.byte	0
237reset_video:
238	.byte	0
239
240	ALIGN_DATA
241bootgdt:
242	.long	0x00000000
243	.long	0x00000000
244	.long	0x00000000
245	.long	0x00000000
246	.long	0x00000000
247	.long	0x00000000
248	.long	0x00000000
249	.long	0x00000000
250
251bootcode64:
252	.long	0x0000ffff
253	.long	0x00af9b00
254
255bootdata64:
256	.long	0x0000ffff
257	.long	0x00af9300
258
259bootcode32:
260	.long	0x0000ffff
261	.long	0x00cf9b00
262
263bootdata32:
264	.long	0x0000ffff
265	.long	0x00cf9300
266bootgdtend:
267
268wakeup_pagetables:
269	.long	0
270
271bootgdtdesc:
272	.word	bootgdtend - bootgdt	/* Length */
273	.long	bootgdt - wakeup_start	/* Offset plus %ds << 4 */
274
275	ALIGN_DATA
276wakeup_pcb:
277	.quad	0
278wakeup_ret:
279	.quad	0
280wakeup_efer:
281	.quad	0
282wakeup_gdt:
283	.word	0
284	.quad	0
285dummy:
286