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/*-
* Copyright (c) 2001 Takanori Watanabe <takawata@jp.freebsd.org>
* Copyright (c) 2001 Mitsuru IWASAKI <iwasaki@jp.freebsd.org>
* Copyright (c) 2003 Peter Wemm
* Copyright (c) 2008-2009 Jung-uk Kim <jkim@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#define LOCORE
#include <machine/asmacros.h>
#include <machine/specialreg.h>
#include "assym.s"
/*
* Resume entry point for real mode.
*
* If XFirmwareWakingVector is zero and FirmwareWakingVector is non-zero
* in FACS, the BIOS enters here in real mode after POST with CS set to
* (FirmwareWakingVector >> 4) and IP set to (FirmwareWakingVector & 0xf).
* Depending on the previous sleep state, we may need to initialize more
* of the system (i.e., S3 suspend-to-RAM vs. S4 suspend-to-disk).
*
* Note: If XFirmwareWakingVector is non-zero, it should disable address
* translation/paging and interrupts, load all segment registers with
* a flat 4 GB address space, and set EFLAGS.IF to zero. Currently
* this mode is not supported by this code.
*/
.data /* So we can modify it */
ALIGN_TEXT
.code16
wakeup_start:
/*
* Set up segment registers for real mode, a small stack for
* any calls we make, and clear any flags.
*/
cli /* make sure no interrupts */
mov %cs, %ax /* copy %cs to %ds. Remember these */
mov %ax, %ds /* are offsets rather than selectors */
mov %ax, %ss
movw $PAGE_SIZE, %sp
xorw %ax, %ax
pushw %ax
popfw
/* To debug resume hangs, beep the speaker if the user requested. */
testb $~0, resume_beep - wakeup_start
jz 1f
movb $0, resume_beep - wakeup_start
movb $0xc0, %al
outb %al, $0x42
movb $0x04, %al
outb %al, $0x42
inb $0x61, %al
orb $0x3, %al
outb %al, $0x61
1:
/* Re-initialize video BIOS if the reset_video tunable is set. */
testb $~0, reset_video - wakeup_start
jz 1f
movb $0, reset_video - wakeup_start
lcall $0xc000, $3
/* Re-start in case the previous BIOS call clobbers them. */
jmp wakeup_start
1:
/*
* Find relocation base and patch the gdt descript and ljmp targets
*/
xorl %ebx, %ebx
mov %cs, %bx
sall $4, %ebx /* %ebx is now our relocation base */
/*
* Load the descriptor table pointer. We'll need it when running
* in 16-bit protected mode.
*/
lgdtl bootgdtdesc - wakeup_start
/* Enable protected mode */
movl $CR0_PE, %eax
mov %eax, %cr0
/*
* Now execute a far jump to turn on protected mode. This
* causes the segment registers to turn into selectors and causes
* %cs to be loaded from the gdt.
*
* The following instruction is:
* ljmpl $bootcode32 - bootgdt, $wakeup_32 - wakeup_start
* but gas cannot assemble that. And besides, we patch the targets
* in early startup and its a little clearer what we are patching.
*/
wakeup_sw32:
.byte 0x66 /* size override to 32 bits */
.byte 0xea /* opcode for far jump */
.long wakeup_32 - wakeup_start /* offset in segment */
.word bootcode32 - bootgdt /* index in gdt for 32 bit code */
/*
* At this point, we are running in 32 bit legacy protected mode.
*/
ALIGN_TEXT
.code32
wakeup_32:
mov $bootdata32 - bootgdt, %eax
mov %ax, %ds
/* Turn on the PAE and PSE bits for when paging is enabled */
mov %cr4, %eax
orl $(CR4_PAE | CR4_PSE), %eax
mov %eax, %cr4
/*
* Enable EFER.LME so that we get long mode when all the prereqs are
* in place. In this case, it turns on when CR0_PG is finally enabled.
* Pick up a few other EFER bits that we'll use need we're here.
*/
movl $MSR_EFER, %ecx
rdmsr
orl $EFER_LME | EFER_SCE, %eax
wrmsr
/*
* Point to the embedded page tables for startup. Note that this
* only gets accessed after we're actually in 64 bit mode, however
* we can only set the bottom 32 bits of %cr3 in this state. This
* means we are required to use a temporary page table that is below
* the 4GB limit. %ebx is still our relocation base. We could just
* subtract 3 * PAGE_SIZE, but that would be too easy.
*/
leal wakeup_pagetables - wakeup_start(%ebx), %eax
movl (%eax), %eax
mov %eax, %cr3
/*
* Finally, switch to long bit mode by enabling paging. We have
* to be very careful here because all the segmentation disappears
* out from underneath us. The spec says we can depend on the
* subsequent pipelined branch to execute, but *only if* everthing
* is still identity mapped. If any mappings change, the pipeline
* will flush.
*/
mov %cr0, %eax
orl $CR0_PG, %eax
mov %eax, %cr0
/*
* At this point paging is enabled, and we are in "compatability" mode.
* We do another far jump to reload %cs with the 64 bit selector.
* %cr3 points to a 4-level page table page.
* We cannot yet jump all the way to the kernel because we can only
* specify a 32 bit linear address. So, yet another trampoline.
*
* The following instruction is:
* ljmp $bootcode64 - bootgdt, $wakeup_64 - wakeup_start
* but gas cannot assemble that. And besides, we patch the targets
* in early startup and its a little clearer what we are patching.
*/
wakeup_sw64:
.byte 0xea /* opcode for far jump */
.long wakeup_64 - wakeup_start /* offset in segment */
.word bootcode64 - bootgdt /* index in gdt for 64 bit code */
/*
* Yeehar! We're running in 64-bit mode! We can mostly ignore our
* segment registers, and get on with it.
* Note that we are running at the correct virtual address, but with
* a 1:1 1GB mirrored mapping over entire address space. We had better
* switch to a real %cr3 promptly so that we can get to the direct map
* space. Remember that jmp is relative and that we've been relocated,
* so use an indirect jump.
*/
ALIGN_TEXT
.code64
wakeup_64:
mov $bootdata64 - bootgdt, %eax
mov %ax, %ds
/* Restore arguments and return. */
movq wakeup_ctx - wakeup_start(%rbx), %rdi
movq wakeup_kpml4 - wakeup_start(%rbx), %rsi
movq wakeup_retaddr - wakeup_start(%rbx), %rax
jmp *%rax
.data
resume_beep:
.byte 0
reset_video:
.byte 0
ALIGN_DATA
bootgdt:
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x00000000
bootcode64:
.long 0x0000ffff
.long 0x00af9b00
bootdata64:
.long 0x0000ffff
.long 0x00af9300
bootcode32:
.long 0x0000ffff
.long 0x00cf9b00
bootdata32:
.long 0x0000ffff
.long 0x00cf9300
bootgdtend:
wakeup_pagetables:
.long 0
bootgdtdesc:
.word bootgdtend - bootgdt /* Length */
.long bootgdt - wakeup_start /* Offset plus %ds << 4 */
ALIGN_DATA
wakeup_retaddr:
.quad 0
wakeup_kpml4:
.quad 0
wakeup_ctx:
.quad 0
wakeup_xpcb:
.quad 0
wakeup_gdt:
.word 0
.quad 0
ALIGN_DATA
wakeup_efer:
.quad 0
wakeup_pat:
.quad 0
wakeup_star:
.quad 0
wakeup_lstar:
.quad 0
wakeup_cstar:
.quad 0
wakeup_sfmask:
.quad 0
wakeup_cpu:
.long 0
dummy:
|
