freebsd-nq/sys/i386/acpica/acpi_wakecode.S
Bruce Evans c93ea91c54 Minor cleanups found while fixing a bug involving double mapping of low
memory:

Load the kernel eflags less magically, as in locore.  The magic increased
when I removed eflags from the pcb in r305899.

Remove a jump to low memory that became garbage when the i386 version was
mostly replaced by the amd64 version in r235622.

The amd64 version is very similar.  It still loads the flags magically,
but is not missing comments about using the special page table.

Reviewed by:	kib
2017-12-15 03:05:14 +00:00

202 lines
5.4 KiB
ArmAsm

/*-
* Copyright (c) 2001 Takanori Watanabe <takawata@jp.freebsd.org>
* Copyright (c) 2001-2012 Mitsuru IWASAKI <iwasaki@jp.freebsd.org>
* Copyright (c) 2003 Peter Wemm
* Copyright (c) 2008-2012 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.
*
* $FreeBSD$
*/
#include <machine/asmacros.h>
#include <machine/ppireg.h>
#include <machine/specialreg.h>
#include <machine/timerreg.h>
#include "assym.s"
/*
* Resume entry point. The BIOS enters here in real mode after POST with
* CS set to the page where we stored this code. It should configure the
* segment registers with a flat 4 GB address space and EFLAGS.IF = 0.
* 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).
*/
.data /* So we can modify it */
ALIGN_TEXT
.code16
wakeup_start:
/*
* Set up segment registers for real mode and a small stack for
* any calls we make. Set up full 32-bit bootstrap kernel flags
* since resumectx() doesn't restore flags. PSL_KERNEL gives
* bootstrap kernel flags (with interrupts disabled), not normal
* kernel 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
pushl $PSL_KERNEL
popfl
/* 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
/* Set PIC timer2 to beep. */
movb $(TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT), %al
outb %al, $TIMER_MODE
/* Turn on speaker. */
inb $IO_PPI, %al
orb $PIT_SPKR, %al
outb %al, $IO_PPI
/* Set frequency. */
movw $0x4c0, %ax
outb %al, $TIMER_CNTR2
shrw $8, %ax
outb %al, $TIMER_CNTR2
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
/* When we reach here, int 0x10 should be ready. Hide cursor. */
movb $0x01, %ah
movb $0x20, %ch
int $0x10
/* 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
/* Get PCB and return address. */
movl wakeup_pcb - wakeup_start(%ebx), %ecx
movl wakeup_ret - wakeup_start(%ebx), %edx
/* Restore CR4 and CR3. */
movl wakeup_cr4 - wakeup_start(%ebx), %eax
mov %eax, %cr4
movl wakeup_cr3 - wakeup_start(%ebx), %eax
mov %eax, %cr3
/* Enable paging. */
mov %cr0, %eax
orl $CR0_PG, %eax
mov %eax, %cr0
/* Jump to return address. */
jmp *%edx
.data
resume_beep:
.byte 0
reset_video:
.byte 0
ALIGN_DATA
bootgdt:
.long 0x00000000
.long 0x00000000
bootcode32:
.long 0x0000ffff
.long 0x00cf9b00
bootdata32:
.long 0x0000ffff
.long 0x00cf9300
bootgdtend:
bootgdtdesc:
.word bootgdtend - bootgdt /* Length */
.long bootgdt - wakeup_start /* Offset plus %ds << 4 */
ALIGN_DATA
wakeup_cr4:
.long 0
wakeup_cr3:
.long 0
wakeup_pcb:
.long 0
wakeup_ret:
.long 0
wakeup_gdt: /* not used */
.word 0
.long 0
dummy: