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Commit d8e1baf1 authored by Vivek Goyal's avatar Vivek Goyal Committed by Andi Kleen
Browse files

[PATCH] x86-64: 64bit ACPI wakeup trampoline 



o Moved wakeup_level4_pgt into the wakeup routine so we can
  run the kernel above 4G.

o Now we first go to 64bit mode and continue to run from trampoline and
  then then start accessing kernel symbols and restore processor context.
  This enables us to resume even in relocatable kernel context when
  kernel might not be loaded at physical addr it has been compiled for.

o Removed the need for modifying any existing kernel page table.

o Increased the size of the wakeup routine to 8K. This is required as
  wake page tables are on trampoline itself and they got to be at 4K
  boundary, hence one page is not sufficient.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent 275f5517

arch/x86_64/kernel/acpi/sleep.c

+4 −20
Original line number Diff line number Diff line
@@ -60,19 +60,6 @@ extern char wakeup_start, wakeup_end; 


extern unsigned long acpi_copy_wakeup_routine(unsigned long);



static pgd_t low_ptr;



static void init_low_mapping(void)

{

	pgd_t *slot0 = pgd_offset(current->mm, 0UL);

	low_ptr = *slot0;

	/* FIXME: We're playing with the current task's page tables here, which

	 * is potentially dangerous on SMP systems.

	 */

	set_pgd(slot0, *pgd_offset(current->mm, PAGE_OFFSET));

	local_flush_tlb();

}



/**

 * acpi_save_state_mem - save kernel state

 *
@@ -81,8 +68,6 @@ static void init_low_mapping(void) 
 */

int acpi_save_state_mem(void)

{

	init_low_mapping();



	memcpy((void *)acpi_wakeup_address, &wakeup_start,

	       &wakeup_end - &wakeup_start);

	acpi_copy_wakeup_routine(acpi_wakeup_address);
@@ -95,8 +80,6 @@ int acpi_save_state_mem(void) 
 */

void acpi_restore_state_mem(void)

{

	set_pgd(pgd_offset(current->mm, 0UL), low_ptr);

	local_flush_tlb();

}



/**
@@ -109,10 +92,11 @@ void acpi_restore_state_mem(void) 
 */

void __init acpi_reserve_bootmem(void)

{

	acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE);

	if ((&wakeup_end - &wakeup_start) > PAGE_SIZE)

	acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE*2);

	if ((&wakeup_end - &wakeup_start) > (PAGE_SIZE*2))

		printk(KERN_CRIT

		       "ACPI: Wakeup code way too big, will crash on attempt to suspend\n");

		       "ACPI: Wakeup code way too big, will crash on attempt"

		       " to suspend\n");

}



static int __init acpi_sleep_setup(char *str)

arch/x86_64/kernel/acpi/wakeup.S

+37 −22
Original line number Diff line number Diff line 
.text

#include <linux/linkage.h>

#include <asm/segment.h>

#include <asm/pgtable.h>

#include <asm/page.h>

#include <asm/msr.h>
@@ -62,12 +63,15 @@ wakeup_code: 


	movb	$0xa2, %al	;  outb %al, $0x80

	

	lidt	%ds:idt_48a - wakeup_code

	xorl	%eax, %eax

	movw	%ds, %ax			# (Convert %ds:gdt to a linear ptr)

	shll	$4, %eax

	addl	$(gdta - wakeup_code), %eax

	movl	%eax, gdt_48a +2 - wakeup_code

	mov	%ds, %ax			# Find 32bit wakeup_code addr

	movzx   %ax, %esi			# (Convert %ds:gdt to a liner ptr)

	shll    $4, %esi

						# Fix up the vectors

	addl    %esi, wakeup_32_vector - wakeup_code

	addl    %esi, wakeup_long64_vector - wakeup_code

	addl    %esi, gdt_48a + 2 - wakeup_code # Fixup the gdt pointer



	lidtl	%ds:idt_48a - wakeup_code

	lgdtl	%ds:gdt_48a - wakeup_code	# load gdt with whatever is

						# appropriate
@@ -80,7 +84,7 @@ wakeup_code: 


	.balign 4

wakeup_32_vector:

	.long   wakeup_32 - __START_KERNEL_map

	.long   wakeup_32 - wakeup_code

	.word   __KERNEL32_CS, 0



	.code32
@@ -103,10 +107,6 @@ wakeup_32: 
	movl	$__KERNEL_DS, %eax

	movl	%eax, %ds



	movl	saved_magic - __START_KERNEL_map, %eax

	cmpl	$0x9abcdef0, %eax

	jne	bogus_32_magic



	movw	$0x0e00 + 'i', %ds:(0xb8012)

	movb	$0xa8, %al	;  outb %al, $0x80;
@@ -120,7 +120,7 @@ wakeup_32: 
	movl	%eax, %cr4



	/* Setup early boot stage 4 level pagetables */

	movl	$(wakeup_level4_pgt - __START_KERNEL_map), %eax

	leal    (wakeup_level4_pgt - wakeup_code)(%esi), %eax

	movl	%eax, %cr3



	/* Enable Long Mode */
@@ -159,11 +159,11 @@ wakeup_32: 
	 */



	/* Finally jump in 64bit mode */

	ljmp	*(wakeup_long64_vector - __START_KERNEL_map)

        ljmp    *(wakeup_long64_vector - wakeup_code)(%esi)



	.balign 4

wakeup_long64_vector:

	.long   wakeup_long64 - __START_KERNEL_map

	.long   wakeup_long64 - wakeup_code

	.word   __KERNEL_CS, 0



.code64
@@ -178,11 +178,16 @@ wakeup_long64: 
	 * addresses where we're currently running on. We have to do that here

	 * because in 32bit we couldn't load a 64bit linear address.

	 */

	lgdt	cpu_gdt_descr - __START_KERNEL_map

	lgdt	cpu_gdt_descr



	movw	$0x0e00 + 'n', %ds:(0xb8014)

	movb	$0xa9, %al	;  outb %al, $0x80



	movq    saved_magic, %rax

	movq    $0x123456789abcdef0, %rdx

	cmpq    %rdx, %rax

	jne     bogus_64_magic



	movw	$0x0e00 + 'u', %ds:(0xb8016)

	

	nop
@@ -223,20 +228,21 @@ idt_48a: 
gdt_48a:

	.word	0x800				# gdt limit=2048,

						#  256 GDT entries

	.word	0, 0				# gdt base (filled in later)

	

	.long   gdta - wakeup_code              # gdt base (relocated in later)

	

real_magic:	.quad 0

video_mode:	.quad 0

video_flags:	.quad 0



.code16

bogus_real_magic:

	movb	$0xba,%al	;  outb %al,$0x80

	jmp bogus_real_magic



bogus_32_magic:

.code64

bogus_64_magic:

	movb	$0xb3,%al	;  outb %al,$0x80

	jmp bogus_32_magic

	jmp bogus_64_magic



bogus_cpu:

	movb	$0xbc,%al	;  outb %al,$0x80
@@ -263,6 +269,7 @@ bogus_cpu: 
#define VIDEO_FIRST_V7 0x0900



# Setting of user mode (AX=mode ID) => CF=success

.code16

mode_seta:

	movw	%ax, %bx

#if 0
@@ -313,6 +320,13 @@ wakeup_stack_begin: # Stack grows down 
.org	0xff0

wakeup_stack:		# Just below end of page



.org   0x1000

ENTRY(wakeup_level4_pgt)

	.quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill   510,8,0

	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */

	.quad   level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE



ENTRY(wakeup_end)

	

##
@@ -338,9 +352,10 @@ ENTRY(acpi_copy_wakeup_routine) 
	movq	$0x123456789abcdef0, %rdx

	movq	%rdx, saved_magic



	movl	saved_magic - __START_KERNEL_map, %eax

	cmpl	$0x9abcdef0, %eax

	jne	bogus_32_magic

	movq    saved_magic, %rax

	movq    $0x123456789abcdef0, %rdx

	cmpq    %rdx, %rax

	jne     bogus_64_magic



	# restore the regs we used

	popq	%rdx

arch/x86_64/kernel/head.S

+0 −9
Original line number Diff line number Diff line
@@ -308,15 +308,6 @@ NEXT_PAGE(level2_kernel_pgt) 


	.data



#ifdef CONFIG_ACPI_SLEEP

	.align PAGE_SIZE

ENTRY(wakeup_level4_pgt)

	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill	510,8,0

	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */

	.quad	level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE

#endif



#ifndef CONFIG_HOTPLUG_CPU

	__INITDATA

#endif