Commit 4b4f7280 authored by H. Peter Anvin's avatar H. Peter Anvin Committed by Ingo Molnar
Browse files

x86 ACPI: normalize segment descriptor register on resume

Some Dell laptops enter resume with apparent garbage in the segment
descriptor registers (almost certainly the result of a botched
transition from protected to real mode.)  The only way to clean that
up is to enter protected mode ourselves and clean out the descriptor
registers.

This fixes resume on Dell XPS M1210 and Dell D620.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=10927

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: pm list <linux-pm@lists.linux-foundation.org>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Tested-by: default avatarKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b8a0b6cc
......@@ -5,6 +5,7 @@
#include <asm/msr-index.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor-flags.h>
.code16
.section ".header", "a"
......@@ -24,6 +25,11 @@ pmode_gdt: .quad 0
realmode_flags: .long 0
real_magic: .long 0
trampoline_segment: .word 0
_pad1: .byte 0
wakeup_jmp: .byte 0xea /* ljmpw */
wakeup_jmp_off: .word 3f
wakeup_jmp_seg: .word 0
wakeup_gdt: .quad 0, 0, 0
signature: .long 0x51ee1111
.text
......@@ -34,11 +40,34 @@ _start:
cli
cld
/* Apparently some dimwit BIOS programmers don't know how to
program a PM to RM transition, and we might end up here with
junk in the data segment descriptor registers. The only way
to repair that is to go into PM and fix it ourselves... */
movw $16, %cx
lgdtl %cs:wakeup_gdt
movl %cr0, %eax
orb $X86_CR0_PE, %al
movl %eax, %cr0
jmp 1f
1: ljmpw $8, $2f
2:
movw %cx, %ds
movw %cx, %es
movw %cx, %ss
movw %cx, %fs
movw %cx, %gs
andb $~X86_CR0_PE, %al
movl %eax, %cr0
jmp wakeup_jmp
3:
/* Set up segments */
movw %cs, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %ss
lidtl wakeup_idt
movl $wakeup_stack_end, %esp
......@@ -98,7 +127,14 @@ bogus_real_magic:
jmp 1b
.data
.balign 4
.balign 8
/* This is the standard real-mode IDT */
wakeup_idt:
.word 0xffff /* limit */
.long 0 /* address */
.word 0
.globl HEAP, heap_end
HEAP:
.long wakeup_heap
......
......@@ -24,6 +24,11 @@ struct wakeup_header {
u32 realmode_flags;
u32 real_magic;
u16 trampoline_segment; /* segment with trampoline code, 64-bit only */
u8 _pad1;
u8 wakeup_jmp;
u16 wakeup_jmp_off;
u16 wakeup_jmp_seg;
u64 wakeup_gdt[3];
u32 signature; /* To check we have correct structure */
} __attribute__((__packed__));
......
......@@ -50,6 +50,20 @@ int acpi_save_state_mem(void)
header->video_mode = saved_video_mode;
header->wakeup_jmp_seg = acpi_wakeup_address >> 4;
/* GDT[0]: GDT self-pointer */
header->wakeup_gdt[0] =
(u64)(sizeof(header->wakeup_gdt) - 1) +
((u64)(acpi_wakeup_address +
((char *)&header->wakeup_gdt - (char *)acpi_realmode))
<< 16);
/* GDT[1]: real-mode-like code segment */
header->wakeup_gdt[1] = (0x009bULL << 40) +
((u64)acpi_wakeup_address << 16) + 0xffff;
/* GDT[2]: real-mode-like data segment */
header->wakeup_gdt[2] = (0x0093ULL << 40) +
((u64)acpi_wakeup_address << 16) + 0xffff;
#ifndef CONFIG_64BIT
store_gdt((struct desc_ptr *)&header->pmode_gdt);
......@@ -111,7 +125,7 @@ void __init acpi_reserve_bootmem(void)
return;
}
acpi_wakeup_address = acpi_realmode;
acpi_wakeup_address = virt_to_phys((void *)acpi_realmode);
}
......
......@@ -36,9 +36,8 @@ static int acpi_sleep_prepare(u32 acpi_state)
if (!acpi_wakeup_address) {
return -EFAULT;
}
acpi_set_firmware_waking_vector((acpi_physical_address)
virt_to_phys((void *)
acpi_wakeup_address));
acpi_set_firmware_waking_vector(
(acpi_physical_address)acpi_wakeup_address);
}
ACPI_FLUSH_CPU_CACHE();
......
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