2 * Suspend support specific for i386/x86-64.
4 * Distribute under GPLv2
6 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
7 * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
8 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
11 #include <linux/suspend.h>
12 #include <linux/export.h>
13 #include <linux/smp.h>
14 #include <linux/perf_event.h>
15 #include <linux/tboot.h>
17 #include <asm/pgtable.h>
18 #include <asm/proto.h>
22 #include <asm/suspend.h>
23 #include <asm/fpu/internal.h>
24 #include <asm/debugreg.h>
26 #include <asm/mmu_context.h>
27 #include <linux/dmi.h>
30 __visible
unsigned long saved_context_ebx
;
31 __visible
unsigned long saved_context_esp
, saved_context_ebp
;
32 __visible
unsigned long saved_context_esi
, saved_context_edi
;
33 __visible
unsigned long saved_context_eflags
;
35 struct saved_context saved_context
;
37 static void msr_save_context(struct saved_context
*ctxt
)
39 struct saved_msr
*msr
= ctxt
->saved_msrs
.array
;
40 struct saved_msr
*end
= msr
+ ctxt
->saved_msrs
.num
;
43 msr
->valid
= !rdmsrl_safe(msr
->info
.msr_no
, &msr
->info
.reg
.q
);
48 static void msr_restore_context(struct saved_context
*ctxt
)
50 struct saved_msr
*msr
= ctxt
->saved_msrs
.array
;
51 struct saved_msr
*end
= msr
+ ctxt
->saved_msrs
.num
;
55 wrmsrl(msr
->info
.msr_no
, msr
->info
.reg
.q
);
61 * __save_processor_state - save CPU registers before creating a
62 * hibernation image and before restoring the memory state from it
63 * @ctxt - structure to store the registers contents in
65 * NOTE: If there is a CPU register the modification of which by the
66 * boot kernel (ie. the kernel used for loading the hibernation image)
67 * might affect the operations of the restored target kernel (ie. the one
68 * saved in the hibernation image), then its contents must be saved by this
69 * function. In other words, if kernel A is hibernated and different
70 * kernel B is used for loading the hibernation image into memory, the
71 * kernel A's __save_processor_state() function must save all registers
72 * needed by kernel A, so that it can operate correctly after the resume
73 * regardless of what kernel B does in the meantime.
75 static void __save_processor_state(struct saved_context
*ctxt
)
78 mtrr_save_fixed_ranges(NULL
);
86 store_idt(&ctxt
->idt
);
89 store_idt((struct desc_ptr
*)&ctxt
->idt_limit
);
92 * We save it here, but restore it only in the hibernate case.
93 * For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit
94 * mode in "secondary_startup_64". In 32-bit mode it is done via
95 * 'pmode_gdt' in wakeup_start.
97 ctxt
->gdt_desc
.size
= GDT_SIZE
- 1;
98 ctxt
->gdt_desc
.address
= (unsigned long)get_cpu_gdt_rw(smp_processor_id());
102 /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
107 savesegment(es
, ctxt
->es
);
108 savesegment(fs
, ctxt
->fs
);
109 savesegment(gs
, ctxt
->gs
);
110 savesegment(ss
, ctxt
->ss
);
113 asm volatile ("movw %%ds, %0" : "=m" (ctxt
->ds
));
114 asm volatile ("movw %%es, %0" : "=m" (ctxt
->es
));
115 asm volatile ("movw %%fs, %0" : "=m" (ctxt
->fs
));
116 asm volatile ("movw %%gs, %0" : "=m" (ctxt
->gs
));
117 asm volatile ("movw %%ss, %0" : "=m" (ctxt
->ss
));
119 rdmsrl(MSR_FS_BASE
, ctxt
->fs_base
);
120 rdmsrl(MSR_GS_BASE
, ctxt
->gs_base
);
121 rdmsrl(MSR_KERNEL_GS_BASE
, ctxt
->gs_kernel_base
);
122 mtrr_save_fixed_ranges(NULL
);
124 rdmsrl(MSR_EFER
, ctxt
->efer
);
130 ctxt
->cr0
= read_cr0();
131 ctxt
->cr2
= read_cr2();
132 ctxt
->cr3
= __read_cr3();
133 ctxt
->cr4
= __read_cr4();
135 ctxt
->cr8
= read_cr8();
137 ctxt
->misc_enable_saved
= !rdmsrl_safe(MSR_IA32_MISC_ENABLE
,
139 msr_save_context(ctxt
);
142 /* Needed by apm.c */
143 void save_processor_state(void)
145 __save_processor_state(&saved_context
);
146 x86_platform
.save_sched_clock_state();
149 EXPORT_SYMBOL(save_processor_state
);
152 static void do_fpu_end(void)
155 * Restore FPU regs if necessary.
160 static void fix_processor_context(void)
162 int cpu
= smp_processor_id();
163 struct tss_struct
*t
= &per_cpu(cpu_tss
, cpu
);
165 struct desc_struct
*desc
= get_cpu_gdt_rw(cpu
);
168 set_tss_desc(cpu
, t
); /*
169 * This just modifies memory; should not be
170 * necessary. But... This is necessary, because
171 * 386 hardware has concept of busy TSS or some
176 memcpy(&tss
, &desc
[GDT_ENTRY_TSS
], sizeof(tss_desc
));
177 tss
.type
= 0x9; /* The available 64-bit TSS (see AMD vol 2, pg 91 */
178 write_gdt_entry(desc
, GDT_ENTRY_TSS
, &tss
, DESC_TSS
);
180 syscall_init(); /* This sets MSR_*STAR and related */
182 load_TR_desc(); /* This does ltr */
183 load_mm_ldt(current
->active_mm
); /* This does lldt */
184 initialize_tlbstate_and_flush();
188 /* The processor is back on the direct GDT, load back the fixmap */
189 load_fixmap_gdt(cpu
);
193 * __restore_processor_state - restore the contents of CPU registers saved
194 * by __save_processor_state()
195 * @ctxt - structure to load the registers contents from
197 static void notrace
__restore_processor_state(struct saved_context
*ctxt
)
199 if (ctxt
->misc_enable_saved
)
200 wrmsrl(MSR_IA32_MISC_ENABLE
, ctxt
->misc_enable
);
204 /* cr4 was introduced in the Pentium CPU */
207 __write_cr4(ctxt
->cr4
);
210 wrmsrl(MSR_EFER
, ctxt
->efer
);
211 write_cr8(ctxt
->cr8
);
212 __write_cr4(ctxt
->cr4
);
214 write_cr3(ctxt
->cr3
);
215 write_cr2(ctxt
->cr2
);
216 write_cr0(ctxt
->cr0
);
219 * now restore the descriptor tables to their proper values
220 * ltr is done i fix_processor_context().
223 load_idt(&ctxt
->idt
);
226 load_idt((const struct desc_ptr
*)&ctxt
->idt_limit
);
231 * We need GSBASE restored before percpu access can work.
232 * percpu access can happen in exception handlers or in complicated
233 * helpers like load_gs_index().
235 wrmsrl(MSR_GS_BASE
, ctxt
->gs_base
);
238 fix_processor_context();
241 * Restore segment registers. This happens after restoring the GDT
242 * and LDT, which happen in fix_processor_context().
245 loadsegment(es
, ctxt
->es
);
246 loadsegment(fs
, ctxt
->fs
);
247 loadsegment(gs
, ctxt
->gs
);
248 loadsegment(ss
, ctxt
->ss
);
253 if (boot_cpu_has(X86_FEATURE_SEP
))
257 asm volatile ("movw %0, %%ds" :: "r" (ctxt
->ds
));
258 asm volatile ("movw %0, %%es" :: "r" (ctxt
->es
));
259 asm volatile ("movw %0, %%fs" :: "r" (ctxt
->fs
));
260 load_gs_index(ctxt
->gs
);
261 asm volatile ("movw %0, %%ss" :: "r" (ctxt
->ss
));
264 * Restore FSBASE and user GSBASE after reloading the respective
267 wrmsrl(MSR_FS_BASE
, ctxt
->fs_base
);
268 wrmsrl(MSR_KERNEL_GS_BASE
, ctxt
->gs_kernel_base
);
272 tsc_verify_tsc_adjust(true);
273 x86_platform
.restore_sched_clock_state();
275 perf_restore_debug_store();
276 msr_restore_context(ctxt
);
279 /* Needed by apm.c */
280 void notrace
restore_processor_state(void)
282 __restore_processor_state(&saved_context
);
285 EXPORT_SYMBOL(restore_processor_state
);
288 #if defined(CONFIG_HIBERNATION) && defined(CONFIG_HOTPLUG_CPU)
289 static void resume_play_dead(void)
292 tboot_shutdown(TB_SHUTDOWN_WFS
);
296 int hibernate_resume_nonboot_cpu_disable(void)
298 void (*play_dead
)(void) = smp_ops
.play_dead
;
302 * Ensure that MONITOR/MWAIT will not be used in the "play dead" loop
303 * during hibernate image restoration, because it is likely that the
304 * monitored address will be actually written to at that time and then
305 * the "dead" CPU will attempt to execute instructions again, but the
306 * address in its instruction pointer may not be possible to resolve
307 * any more at that point (the page tables used by it previously may
308 * have been overwritten by hibernate image data).
310 smp_ops
.play_dead
= resume_play_dead
;
311 ret
= disable_nonboot_cpus();
312 smp_ops
.play_dead
= play_dead
;
318 * When bsp_check() is called in hibernate and suspend, cpu hotplug
319 * is disabled already. So it's unnessary to handle race condition between
320 * cpumask query and cpu hotplug.
322 static int bsp_check(void)
324 if (cpumask_first(cpu_online_mask
) != 0) {
325 pr_warn("CPU0 is offline.\n");
332 static int bsp_pm_callback(struct notifier_block
*nb
, unsigned long action
,
338 case PM_SUSPEND_PREPARE
:
339 case PM_HIBERNATION_PREPARE
:
342 #ifdef CONFIG_DEBUG_HOTPLUG_CPU0
343 case PM_RESTORE_PREPARE
:
345 * When system resumes from hibernation, online CPU0 because
346 * 1. it's required for resume and
347 * 2. the CPU was online before hibernation
350 _debug_hotplug_cpu(0, 1);
352 case PM_POST_RESTORE
:
354 * When a resume really happens, this code won't be called.
356 * This code is called only when user space hibernation software
357 * prepares for snapshot device during boot time. So we just
358 * call _debug_hotplug_cpu() to restore to CPU0's state prior to
359 * preparing the snapshot device.
361 * This works for normal boot case in our CPU0 hotplug debug
362 * mode, i.e. CPU0 is offline and user mode hibernation
363 * software initializes during boot time.
365 * If CPU0 is online and user application accesses snapshot
366 * device after boot time, this will offline CPU0 and user may
367 * see different CPU0 state before and after accessing
368 * the snapshot device. But hopefully this is not a case when
369 * user debugging CPU0 hotplug. Even if users hit this case,
370 * they can easily online CPU0 back.
372 * To simplify this debug code, we only consider normal boot
373 * case. Otherwise we need to remember CPU0's state and restore
374 * to that state and resolve racy conditions etc.
376 _debug_hotplug_cpu(0, 0);
382 return notifier_from_errno(ret
);
385 static int __init
bsp_pm_check_init(void)
388 * Set this bsp_pm_callback as lower priority than
389 * cpu_hotplug_pm_callback. So cpu_hotplug_pm_callback will be called
390 * earlier to disable cpu hotplug before bsp online check.
392 pm_notifier(bsp_pm_callback
, -INT_MAX
);
396 core_initcall(bsp_pm_check_init
);
398 static int msr_init_context(const u32
*msr_id
, const int total_num
)
401 struct saved_msr
*msr_array
;
403 if (saved_context
.saved_msrs
.array
|| saved_context
.saved_msrs
.num
> 0) {
404 pr_err("x86/pm: MSR quirk already applied, please check your DMI match table.\n");
408 msr_array
= kmalloc_array(total_num
, sizeof(struct saved_msr
), GFP_KERNEL
);
410 pr_err("x86/pm: Can not allocate memory to save/restore MSRs during suspend.\n");
414 for (i
= 0; i
< total_num
; i
++) {
415 msr_array
[i
].info
.msr_no
= msr_id
[i
];
416 msr_array
[i
].valid
= false;
417 msr_array
[i
].info
.reg
.q
= 0;
419 saved_context
.saved_msrs
.num
= total_num
;
420 saved_context
.saved_msrs
.array
= msr_array
;
426 * The following section is a quirk framework for problematic BIOSen:
427 * Sometimes MSRs are modified by the BIOSen after suspended to
428 * RAM, this might cause unexpected behavior after wakeup.
429 * Thus we save/restore these specified MSRs across suspend/resume
430 * in order to work around it.
432 * For any further problematic BIOSen/platforms,
433 * please add your own function similar to msr_initialize_bdw.
435 static int msr_initialize_bdw(const struct dmi_system_id
*d
)
437 /* Add any extra MSR ids into this array. */
438 u32 bdw_msr_id
[] = { MSR_IA32_THERM_CONTROL
};
440 pr_info("x86/pm: %s detected, MSR saving is needed during suspending.\n", d
->ident
);
441 return msr_init_context(bdw_msr_id
, ARRAY_SIZE(bdw_msr_id
));
444 static const struct dmi_system_id msr_save_dmi_table
[] = {
446 .callback
= msr_initialize_bdw
,
447 .ident
= "BROADWELL BDX_EP",
449 DMI_MATCH(DMI_PRODUCT_NAME
, "GRANTLEY"),
450 DMI_MATCH(DMI_PRODUCT_VERSION
, "E63448-400"),
456 static int pm_check_save_msr(void)
458 dmi_check_system(msr_save_dmi_table
);
462 device_initcall(pm_check_save_msr
);