1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * sleep.c - x86-specific ACPI sleep support.
  4 *
  5 *  Copyright (C) 2001-2003 Patrick Mochel
  6 *  Copyright (C) 2001-2003 Pavel Machek <pavel@ucw.cz>
  7 */
  8
  9#include <linux/acpi.h>
 10#include <linux/memblock.h>
 11#include <linux/dmi.h>
 12#include <linux/cpumask.h>
 13#include <linux/pgtable.h>
 14#include <asm/segment.h>
 15#include <asm/desc.h>
 16#include <asm/cacheflush.h>
 17#include <asm/realmode.h>
 18#include <asm/hypervisor.h>
 19#include <asm/smp.h>
 20
 21#include <linux/ftrace.h>
 22#include "../../realmode/rm/wakeup.h"
 23#include "sleep.h"
 24
 25unsigned long acpi_realmode_flags;
 26
 27#if defined(CONFIG_SMP) && defined(CONFIG_64BIT)
 28static char temp_stack[4096];
 29#endif
 30
 31/**
 32 * acpi_get_wakeup_address - provide physical address for S3 wakeup
 33 *
 34 * Returns the physical address where the kernel should be resumed after the
 35 * system awakes from S3, e.g. for programming into the firmware waking vector.
 36 */
 37unsigned long acpi_get_wakeup_address(void)
 38{
 39	return ((unsigned long)(real_mode_header->wakeup_start));
 40}
 41
 42/**
 43 * x86_acpi_enter_sleep_state - enter sleep state
 44 * @state: Sleep state to enter.
 45 *
 46 * Wrapper around acpi_enter_sleep_state() to be called by assembly.
 47 */
 48asmlinkage acpi_status __visible x86_acpi_enter_sleep_state(u8 state)
 49{
 50	return acpi_enter_sleep_state(state);
 51}
 52
 53/**
 54 * x86_acpi_suspend_lowlevel - save kernel state
 55 *
 56 * Create an identity mapped page table and copy the wakeup routine to
 57 * low memory.
 58 */
 59int x86_acpi_suspend_lowlevel(void)
 60{
 61	struct wakeup_header *header =
 62		(struct wakeup_header *) __va(real_mode_header->wakeup_header);
 63
 64	if (header->signature != WAKEUP_HEADER_SIGNATURE) {
 65		printk(KERN_ERR "wakeup header does not match\n");
 66		return -EINVAL;
 67	}
 68
 69	header->video_mode = saved_video_mode;
 70
 71	header->pmode_behavior = 0;
 72
 73#ifndef CONFIG_64BIT
 74	native_store_gdt((struct desc_ptr *)&header->pmode_gdt);
 75
 76	/*
 77	 * We have to check that we can write back the value, and not
 78	 * just read it.  At least on 90 nm Pentium M (Family 6, Model
 79	 * 13), reading an invalid MSR is not guaranteed to trap, see
 80	 * Erratum X4 in "Intel Pentium M Processor on 90 nm Process
 81	 * with 2-MB L2 Cache and Intel® Processor A100 and A110 on 90
 82	 * nm process with 512-KB L2 Cache Specification Update".
 83	 */
 84	if (!rdmsr_safe(MSR_EFER,
 85			&header->pmode_efer_low,
 86			&header->pmode_efer_high) &&
 87	    !wrmsr_safe(MSR_EFER,
 88			header->pmode_efer_low,
 89			header->pmode_efer_high))
 90		header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_EFER);
 91#endif /* !CONFIG_64BIT */
 92
 93	header->pmode_cr0 = read_cr0();
 94	if (__this_cpu_read(cpu_info.cpuid_level) >= 0) {
 95		header->pmode_cr4 = __read_cr4();
 96		header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_CR4);
 97	}
 98	if (!rdmsr_safe(MSR_IA32_MISC_ENABLE,
 99			&header->pmode_misc_en_low,
100			&header->pmode_misc_en_high) &&
101	    !wrmsr_safe(MSR_IA32_MISC_ENABLE,
102			header->pmode_misc_en_low,
103			header->pmode_misc_en_high))
104		header->pmode_behavior |=
105			(1 << WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE);
106	header->realmode_flags = acpi_realmode_flags;
107	header->real_magic = 0x12345678;
108
109#ifndef CONFIG_64BIT
110	header->pmode_entry = (u32)&wakeup_pmode_return;
111	header->pmode_cr3 = (u32)__pa_symbol(initial_page_table);
112	saved_magic = 0x12345678;
113#else /* CONFIG_64BIT */
114#ifdef CONFIG_SMP
115	/*
116	 * As each CPU starts up, it will find its own stack pointer
117	 * from its current_task->thread.sp. Typically that will be
118	 * the idle thread for a newly-started AP, or even the boot
119	 * CPU which will find it set to &init_task in the static
120	 * per-cpu data.
121	 *
122	 * Make the resuming CPU use the temporary stack at startup
123	 * by setting current->thread.sp to point to that. The true
124	 * %rsp will be restored with the rest of the CPU context,
125	 * by do_suspend_lowlevel(). And unwinders don't care about
126	 * the abuse of ->thread.sp because it's a dead variable
127	 * while the thread is running on the CPU anyway; the true
128	 * value is in the actual %rsp register.
129	 */
130	current->thread.sp = (unsigned long)temp_stack + sizeof(temp_stack);
131	/*
132	 * Ensure the CPU knows which one it is when it comes back, if
133	 * it isn't in parallel mode and expected to work that out for
134	 * itself.
135	 */
136	if (!(smpboot_control & STARTUP_PARALLEL_MASK))
137		smpboot_control = smp_processor_id();
138#endif
139	initial_code = (unsigned long)wakeup_long64;
140	saved_magic = 0x123456789abcdef0L;
141#endif /* CONFIG_64BIT */
142
143	/*
144	 * Pause/unpause graph tracing around do_suspend_lowlevel as it has
145	 * inconsistent call/return info after it jumps to the wakeup vector.
146	 */
147	pause_graph_tracing();
148	do_suspend_lowlevel();
149	unpause_graph_tracing();
150	return 0;
151}
152
153static int __init acpi_sleep_setup(char *str)
154{
155	while ((str != NULL) && (*str != '\0')) {
156		if (strncmp(str, "s3_bios", 7) == 0)
157			acpi_realmode_flags |= 1;
158		if (strncmp(str, "s3_mode", 7) == 0)
159			acpi_realmode_flags |= 2;
160		if (strncmp(str, "s3_beep", 7) == 0)
161			acpi_realmode_flags |= 4;
162#ifdef CONFIG_HIBERNATION
163		if (strncmp(str, "s4_hwsig", 8) == 0)
164			acpi_check_s4_hw_signature = 1;
165		if (strncmp(str, "s4_nohwsig", 10) == 0)
166			acpi_check_s4_hw_signature = 0;
167#endif
168		if (strncmp(str, "nonvs", 5) == 0)
169			acpi_nvs_nosave();
170		if (strncmp(str, "nonvs_s3", 8) == 0)
171			acpi_nvs_nosave_s3();
172		if (strncmp(str, "old_ordering", 12) == 0)
173			acpi_old_suspend_ordering();
174		if (strncmp(str, "nobl", 4) == 0)
175			acpi_sleep_no_blacklist();
176		str = strchr(str, ',');
177		if (str != NULL)
178			str += strspn(str, ", \t");
179	}
180	return 1;
181}
182
183__setup("acpi_sleep=", acpi_sleep_setup);
184
185#if defined(CONFIG_HIBERNATION) && defined(CONFIG_HYPERVISOR_GUEST)
186static int __init init_s4_sigcheck(void)
187{
188	/*
189	 * If running on a hypervisor, honour the ACPI specification
190	 * by default and trigger a clean reboot when the hardware
191	 * signature in FACS is changed after hibernation.
192	 */
193	if (acpi_check_s4_hw_signature == -1 &&
194	    !hypervisor_is_type(X86_HYPER_NATIVE))
195		acpi_check_s4_hw_signature = 1;
196
197	return 0;
198}
199/* This must happen before acpi_init() which is a subsys initcall */
200arch_initcall(init_s4_sigcheck);
201#endif