freebsd-skq/sys/i386/acpica/acpi_wakecode.S
kib 1ff881a6a6 Fix resume on i386 PAE.
It was broken before PAE/no-PAE merge, but since now PAE is the
default, resume is apparently becomes for all machines.

The corrected issues:
- the trampoline page is not mapped executable, so machine faults when
  paging is on;
- MSR.EFER and %cr4 both should be loaded before paging is enabled,
  otherwise paging structures are invalid (cr4.PAE and EFER.NX).
- MSR.EFER and %cr4 should be only loaded if present.  I attempt to handle
  this by not touching the registers if the value is zero.

There are some more bits still not quite correct, e.g. unconditional
access to %cr4 in resumectx.

Reported and debugging help by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2019-02-07 02:09:34 +00:00

215 lines
5.6 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.inc"
/*
* 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
/* Restore EFER, CR4 and CR3. */
movl wakeup_efer - wakeup_start(%ebx), %eax
movl wakeup_efer - wakeup_start + 4(%ebx), %edx
cmpl $0, %eax
jne 1f
cmpl $0, %edx
je 2f
1: movl $MSR_EFER, %ecx
wrmsr
2: movl wakeup_cr4 - wakeup_start(%ebx), %eax
cmpl $0, %eax
je 3f
mov %eax, %cr4
3: movl wakeup_cr3 - wakeup_start(%ebx), %eax
mov %eax, %cr3
/* Get PCB and return address. */
movl wakeup_ret - wakeup_start(%ebx), %edx
movl wakeup_pcb - wakeup_start(%ebx), %ecx
/* 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_efer:
.long 0
.long 0
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: