linux/arch/x86/kernel/acpi/sleep.c
Rafael J. Wysocki 57044031b0 ACPI / PM: Make it possible to ignore the system sleep blacklist
The ACPI code supporting system transitions to sleep states uses
an internal blacklist to apply special handling to some machines
reported to behave incorrectly in some ways.

However, some entries of that blacklist cover problematic as well as
non-problematic systems, so give the users of the latter a chance to
ignore the blacklist and run their systems in the default way by
adding acpi_sleep=nobl to the kernel command line.

For example, that allows the users of Dell XPS13 9360 systems not
affected by the issue that caused the blacklist entry for this
machine to be added by commit 71630b7a83 (ACPI / PM: Blacklist Low
Power S0 Idle _DSM for Dell XPS13 9360) to use suspend-to-idle with
the Low Power S0 Idle _DSM interface which in principle should be
more energy-efficient than S3 on them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-11-27 01:44:24 +01:00

151 lines
4.2 KiB
C

// 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/bootmem.h>
#include <linux/memblock.h>
#include <linux/dmi.h>
#include <linux/cpumask.h>
#include <asm/segment.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#include <asm/realmode.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
/**
* x86_acpi_enter_sleep_state - enter sleep state
* @state: Sleep state to enter.
*
* Wrapper around acpi_enter_sleep_state() to be called by assmebly.
*/
acpi_status asmlinkage __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))
header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_EFER);
#endif /* !CONFIG_64BIT */
header->pmode_cr0 = read_cr0();
if (__this_cpu_read(cpu_info.cpuid_level) >= 0) {
header->pmode_cr4 = __read_cr4();
header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_CR4);
}
if (!rdmsr_safe(MSR_IA32_MISC_ENABLE,
&header->pmode_misc_en_low,
&header->pmode_misc_en_high) &&
!wrmsr_safe(MSR_IA32_MISC_ENABLE,
header->pmode_misc_en_low,
header->pmode_misc_en_high))
header->pmode_behavior |=
(1 << WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE);
header->realmode_flags = acpi_realmode_flags;
header->real_magic = 0x12345678;
#ifndef CONFIG_64BIT
header->pmode_entry = (u32)&wakeup_pmode_return;
header->pmode_cr3 = (u32)__pa_symbol(initial_page_table);
saved_magic = 0x12345678;
#else /* CONFIG_64BIT */
#ifdef CONFIG_SMP
initial_stack = (unsigned long)temp_stack + sizeof(temp_stack);
early_gdt_descr.address =
(unsigned long)get_cpu_gdt_rw(smp_processor_id());
initial_gs = per_cpu_offset(smp_processor_id());
#endif
initial_code = (unsigned long)wakeup_long64;
saved_magic = 0x123456789abcdef0L;
#endif /* CONFIG_64BIT */
/*
* Pause/unpause graph tracing around do_suspend_lowlevel as it has
* inconsistent call/return info after it jumps to the wakeup vector.
*/
pause_graph_tracing();
do_suspend_lowlevel();
unpause_graph_tracing();
return 0;
}
static int __init acpi_sleep_setup(char *str)
{
while ((str != NULL) && (*str != '\0')) {
if (strncmp(str, "s3_bios", 7) == 0)
acpi_realmode_flags |= 1;
if (strncmp(str, "s3_mode", 7) == 0)
acpi_realmode_flags |= 2;
if (strncmp(str, "s3_beep", 7) == 0)
acpi_realmode_flags |= 4;
#ifdef CONFIG_HIBERNATION
if (strncmp(str, "s4_nohwsig", 10) == 0)
acpi_no_s4_hw_signature();
#endif
if (strncmp(str, "nonvs", 5) == 0)
acpi_nvs_nosave();
if (strncmp(str, "nonvs_s3", 8) == 0)
acpi_nvs_nosave_s3();
if (strncmp(str, "old_ordering", 12) == 0)
acpi_old_suspend_ordering();
if (strncmp(str, "nobl", 4) == 0)
acpi_sleep_no_blacklist();
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
}
return 1;
}
__setup("acpi_sleep=", acpi_sleep_setup);