arch/x86/kernel/acpi/sleep.c

Source file repositories/reference/linux-study-clean/arch/x86/kernel/acpi/sleep.c

File Facts

System
Linux kernel
Corpus path
arch/x86/kernel/acpi/sleep.c
Extension
.c
Size
6039 bytes
Lines
203
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * sleep.c - x86-specific ACPI sleep support.
 *
 *  Copyright (C) 2001-2003 Patrick Mochel
 *  Copyright (C) 2001-2003 Pavel Machek <pavel@ucw.cz>
 */

#include <linux/acpi.h>
#include <linux/memblock.h>
#include <linux/dmi.h>
#include <linux/cpumask.h>
#include <linux/pgtable.h>
#include <asm/segment.h>
#include <asm/desc.h>
#include <asm/cacheflush.h>
#include <asm/realmode.h>
#include <asm/hypervisor.h>
#include <asm/msr.h>
#include <asm/smp.h>

#include <linux/ftrace.h>
#include "../../realmode/rm/wakeup.h"
#include "sleep.h"

unsigned long acpi_realmode_flags;

#if defined(CONFIG_SMP) && defined(CONFIG_64BIT)
static char temp_stack[4096];
#endif

/**
 * acpi_get_wakeup_address - provide physical address for S3 wakeup
 *
 * Returns the physical address where the kernel should be resumed after the
 * system awakes from S3, e.g. for programming into the firmware waking vector.
 */
unsigned long acpi_get_wakeup_address(void)
{
	return ((unsigned long)(real_mode_header->wakeup_start));
}

/**
 * x86_acpi_enter_sleep_state - enter sleep state
 * @state: Sleep state to enter.
 *
 * Wrapper around acpi_enter_sleep_state() to be called by assembly.
 */
asmlinkage acpi_status __visible x86_acpi_enter_sleep_state(u8 state)
{
	return acpi_enter_sleep_state(state);
}

/**
 * x86_acpi_suspend_lowlevel - save kernel state
 *
 * Create an identity mapped page table and copy the wakeup routine to
 * low memory.
 */
int x86_acpi_suspend_lowlevel(void)
{
	struct wakeup_header *header =
		(struct wakeup_header *) __va(real_mode_header->wakeup_header);

	if (header->signature != WAKEUP_HEADER_SIGNATURE) {
		printk(KERN_ERR "wakeup header does not match\n");
		return -EINVAL;
	}

	header->video_mode = saved_video_mode;

	header->pmode_behavior = 0;

#ifndef CONFIG_64BIT
	native_store_gdt((struct desc_ptr *)&header->pmode_gdt);

	/*
	 * We have to check that we can write back the value, and not
	 * just read it.  At least on 90 nm Pentium M (Family 6, Model
	 * 13), reading an invalid MSR is not guaranteed to trap, see
	 * Erratum X4 in "Intel Pentium M Processor on 90 nm Process
	 * with 2-MB L2 Cache and Intel® Processor A100 and A110 on 90
	 * nm process with 512-KB L2 Cache Specification Update".
	 */
	if (!rdmsr_safe(MSR_EFER,
			&header->pmode_efer_low,
			&header->pmode_efer_high) &&
	    !wrmsr_safe(MSR_EFER,
			header->pmode_efer_low,
			header->pmode_efer_high))

Annotation

Implementation Notes