arch/x86/power/cpu.c

   1 /*
   2  * Suspend support specific for i386/x86-64.
   3  *
   4  * Distribute under GPLv2
   5  *
   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>
   9  */
  10
  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>
  16
  17 #include <asm/pgtable.h>
  18 #include <asm/proto.h>
  19 #include <asm/mtrr.h>
  20 #include <asm/page.h>
  21 #include <asm/mce.h>
  22 #include <asm/suspend.h>
  23 #include <asm/fpu/internal.h>
  24 #include <asm/debugreg.h>
  25 #include <asm/cpu.h>
  26 #include <asm/mmu_context.h>
  27 #include <linux/dmi.h>
  28
  29 #ifdef CONFIG_X86_32
  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;
  34 #endif
  35 struct saved_context saved_context;
  36
  37 static void msr_save_context(struct saved_context *ctxt)
  38 {
  39         struct saved_msr *msr = ctxt->saved_msrs.array;
  40         struct saved_msr *end = msr + ctxt->saved_msrs.num;
  41
  42         while (msr < end) {
  43                 msr->valid = !rdmsrl_safe(msr->info.msr_no, &msr->info.reg.q);
  44                 msr++;
  45         }
  46 }
  47
  48 static void msr_restore_context(struct saved_context *ctxt)
  49 {
  50         struct saved_msr *msr = ctxt->saved_msrs.array;
  51         struct saved_msr *end = msr + ctxt->saved_msrs.num;
  52
  53         while (msr < end) {
  54                 if (msr->valid)
  55                         wrmsrl(msr->info.msr_no, msr->info.reg.q);
  56                 msr++;
  57         }
  58 }
  59
  60 /**
  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
  64  *
  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.
  74  */
  75 static void __save_processor_state(struct saved_context *ctxt)
  76 {
  77 #ifdef CONFIG_X86_32
  78         mtrr_save_fixed_ranges(NULL);
  79 #endif
  80         kernel_fpu_begin();
  81
  82         /*
  83          * descriptor tables
  84          */
  85 #ifdef CONFIG_X86_32
  86         store_idt(&ctxt->idt);
  87 #else
  88 /* CONFIG_X86_64 */
  89         store_idt((struct desc_ptr *)&ctxt->idt_limit);
  90 #endif
  91         /*
  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.
  96          */
  97         ctxt->gdt_desc.size = GDT_SIZE - 1;
  98         ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_rw(smp_processor_id());
  99
 100         store_tr(ctxt->tr);
 101
 102         /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
 103         /*
 104          * segment registers
 105          */
 106 #ifdef CONFIG_X86_32
 107         savesegment(es, ctxt->es);
 108         savesegment(fs, ctxt->fs);
 109         savesegment(gs, ctxt->gs);
 110         savesegment(ss, ctxt->ss);
 111 #else
 112 /* CONFIG_X86_64 */
 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));
 118
 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);
 123
 124         rdmsrl(MSR_EFER, ctxt->efer);
 125 #endif
 126
 127         /*
 128          * control registers
 129          */
 130         ctxt->cr0 = read_cr0();
 131         ctxt->cr2 = read_cr2();
 132         ctxt->cr3 = read_cr3();
 133         ctxt->cr4 = __read_cr4();
 134 #ifdef CONFIG_X86_64
 135         ctxt->cr8 = read_cr8();
 136 #endif
 137         ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE,
 138                                                &ctxt->misc_enable);
 139         msr_save_context(ctxt);
 140 }
 141
 142 /* Needed by apm.c */
 143 void save_processor_state(void)
 144 {
 145         __save_processor_state(&saved_context);
 146         x86_platform.save_sched_clock_state();
 147 }
 148 #ifdef CONFIG_X86_32
 149 EXPORT_SYMBOL(save_processor_state);
 150 #endif
 151
 152 static void do_fpu_end(void)
 153 {
 154         /*
 155          * Restore FPU regs if necessary.
 156          */
 157         kernel_fpu_end();
 158 }
 159
 160 static void fix_processor_context(void)
 161 {
 162         int cpu = smp_processor_id();
 163         struct tss_struct *t = &per_cpu(cpu_tss, cpu);
 164 #ifdef CONFIG_X86_64
 165         struct desc_struct *desc = get_cpu_gdt_rw(cpu);
 166         tss_desc tss;
 167 #endif
 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
 172                                  * similar stupidity.
 173                                  */
 174
 175 #ifdef CONFIG_X86_64
 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);
 179
 180         syscall_init();                         /* This sets MSR_*STAR and related */
 181 #endif
 182         load_TR_desc();                         /* This does ltr */
 183         load_mm_ldt(current->active_mm);        /* This does lldt */
 184
 185         fpu__resume_cpu();
 186
 187         /* The processor is back on the direct GDT, load back the fixmap */
 188         load_fixmap_gdt(cpu);
 189 }
 190
 191 /**
 192  *      __restore_processor_state - restore the contents of CPU registers saved
 193  *              by __save_processor_state()
 194  *      @ctxt - structure to load the registers contents from
 195  */
 196 static void notrace __restore_processor_state(struct saved_context *ctxt)
 197 {
 198         if (ctxt->misc_enable_saved)
 199                 wrmsrl(MSR_IA32_MISC_ENABLE, ctxt->misc_enable);
 200         /*
 201          * control registers
 202          */
 203         /* cr4 was introduced in the Pentium CPU */
 204 #ifdef CONFIG_X86_32
 205         if (ctxt->cr4)
 206                 __write_cr4(ctxt->cr4);
 207 #else
 208 /* CONFIG X86_64 */
 209         wrmsrl(MSR_EFER, ctxt->efer);
 210         write_cr8(ctxt->cr8);
 211         __write_cr4(ctxt->cr4);
 212 #endif
 213         write_cr3(ctxt->cr3);
 214         write_cr2(ctxt->cr2);
 215         write_cr0(ctxt->cr0);
 216
 217         /*
 218          * now restore the descriptor tables to their proper values
 219          * ltr is done i fix_processor_context().
 220          */
 221 #ifdef CONFIG_X86_32
 222         load_idt(&ctxt->idt);
 223 #else
 224 /* CONFIG_X86_64 */
 225         load_idt((const struct desc_ptr *)&ctxt->idt_limit);
 226 #endif
 227
 228         /*
 229          * segment registers
 230          */
 231 #ifdef CONFIG_X86_32
 232         loadsegment(es, ctxt->es);
 233         loadsegment(fs, ctxt->fs);
 234         loadsegment(gs, ctxt->gs);
 235         loadsegment(ss, ctxt->ss);
 236
 237         /*
 238          * sysenter MSRs
 239          */
 240         if (boot_cpu_has(X86_FEATURE_SEP))
 241                 enable_sep_cpu();
 242 #else
 243 /* CONFIG_X86_64 */
 244         asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
 245         asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
 246         asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));
 247         load_gs_index(ctxt->gs);
 248         asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss));
 249
 250         wrmsrl(MSR_FS_BASE, ctxt->fs_base);
 251         wrmsrl(MSR_GS_BASE, ctxt->gs_base);
 252         wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
 253 #endif
 254
 255         fix_processor_context();
 256
 257         do_fpu_end();
 258         tsc_verify_tsc_adjust(true);
 259         x86_platform.restore_sched_clock_state();
 260         mtrr_bp_restore();
 261         perf_restore_debug_store();
 262         msr_restore_context(ctxt);
 263 }
 264
 265 /* Needed by apm.c */
 266 void notrace restore_processor_state(void)
 267 {
 268         __restore_processor_state(&saved_context);
 269 }
 270 #ifdef CONFIG_X86_32
 271 EXPORT_SYMBOL(restore_processor_state);
 272 #endif
 273
 274 #if defined(CONFIG_HIBERNATION) && defined(CONFIG_HOTPLUG_CPU)
 275 static void resume_play_dead(void)
 276 {
 277         play_dead_common();
 278         tboot_shutdown(TB_SHUTDOWN_WFS);
 279         hlt_play_dead();
 280 }
 281
 282 int hibernate_resume_nonboot_cpu_disable(void)
 283 {
 284         void (*play_dead)(void) = smp_ops.play_dead;
 285         int ret;
 286
 287         /*
 288          * Ensure that MONITOR/MWAIT will not be used in the "play dead" loop
 289          * during hibernate image restoration, because it is likely that the
 290          * monitored address will be actually written to at that time and then
 291          * the "dead" CPU will attempt to execute instructions again, but the
 292          * address in its instruction pointer may not be possible to resolve
 293          * any more at that point (the page tables used by it previously may
 294          * have been overwritten by hibernate image data).
 295          */
 296         smp_ops.play_dead = resume_play_dead;
 297         ret = disable_nonboot_cpus();
 298         smp_ops.play_dead = play_dead;
 299         return ret;
 300 }
 301 #endif
 302
 303 /*
 304  * When bsp_check() is called in hibernate and suspend, cpu hotplug
 305  * is disabled already. So it's unnessary to handle race condition between
 306  * cpumask query and cpu hotplug.
 307  */
 308 static int bsp_check(void)
 309 {
 310         if (cpumask_first(cpu_online_mask) != 0) {
 311                 pr_warn("CPU0 is offline.\n");
 312                 return -ENODEV;
 313         }
 314
 315         return 0;
 316 }
 317
 318 static int bsp_pm_callback(struct notifier_block *nb, unsigned long action,
 319                            void *ptr)
 320 {
 321         int ret = 0;
 322
 323         switch (action) {
 324         case PM_SUSPEND_PREPARE:
 325         case PM_HIBERNATION_PREPARE:
 326                 ret = bsp_check();
 327                 break;
 328 #ifdef CONFIG_DEBUG_HOTPLUG_CPU0
 329         case PM_RESTORE_PREPARE:
 330                 /*
 331                  * When system resumes from hibernation, online CPU0 because
 332                  * 1. it's required for resume and
 333                  * 2. the CPU was online before hibernation
 334                  */
 335                 if (!cpu_online(0))
 336                         _debug_hotplug_cpu(0, 1);
 337                 break;
 338         case PM_POST_RESTORE:
 339                 /*
 340                  * When a resume really happens, this code won't be called.
 341                  *
 342                  * This code is called only when user space hibernation software
 343                  * prepares for snapshot device during boot time. So we just
 344                  * call _debug_hotplug_cpu() to restore to CPU0's state prior to
 345                  * preparing the snapshot device.
 346                  *
 347                  * This works for normal boot case in our CPU0 hotplug debug
 348                  * mode, i.e. CPU0 is offline and user mode hibernation
 349                  * software initializes during boot time.
 350                  *
 351                  * If CPU0 is online and user application accesses snapshot
 352                  * device after boot time, this will offline CPU0 and user may
 353                  * see different CPU0 state before and after accessing
 354                  * the snapshot device. But hopefully this is not a case when
 355                  * user debugging CPU0 hotplug. Even if users hit this case,
 356                  * they can easily online CPU0 back.
 357                  *
 358                  * To simplify this debug code, we only consider normal boot
 359                  * case. Otherwise we need to remember CPU0's state and restore
 360                  * to that state and resolve racy conditions etc.
 361                  */
 362                 _debug_hotplug_cpu(0, 0);
 363                 break;
 364 #endif
 365         default:
 366                 break;
 367         }
 368         return notifier_from_errno(ret);
 369 }
 370
 371 static int __init bsp_pm_check_init(void)
 372 {
 373         /*
 374          * Set this bsp_pm_callback as lower priority than
 375          * cpu_hotplug_pm_callback. So cpu_hotplug_pm_callback will be called
 376          * earlier to disable cpu hotplug before bsp online check.
 377          */
 378         pm_notifier(bsp_pm_callback, -INT_MAX);
 379         return 0;
 380 }
 381
 382 core_initcall(bsp_pm_check_init);
 383
 384 static int msr_init_context(const u32 *msr_id, const int total_num)
 385 {
 386         int i = 0;
 387         struct saved_msr *msr_array;
 388
 389         if (saved_context.saved_msrs.array || saved_context.saved_msrs.num > 0) {
 390                 pr_err("x86/pm: MSR quirk already applied, please check your DMI match table.\n");
 391                 return -EINVAL;
 392         }
 393
 394         msr_array = kmalloc_array(total_num, sizeof(struct saved_msr), GFP_KERNEL);
 395         if (!msr_array) {
 396                 pr_err("x86/pm: Can not allocate memory to save/restore MSRs during suspend.\n");
 397                 return -ENOMEM;
 398         }
 399
 400         for (i = 0; i < total_num; i++) {
 401                 msr_array[i].info.msr_no        = msr_id[i];
 402                 msr_array[i].valid              = false;
 403                 msr_array[i].info.reg.q         = 0;
 404         }
 405         saved_context.saved_msrs.num    = total_num;
 406         saved_context.saved_msrs.array  = msr_array;
 407
 408         return 0;
 409 }
 410
 411 /*
 412  * The following section is a quirk framework for problematic BIOSen:
 413  * Sometimes MSRs are modified by the BIOSen after suspended to
 414  * RAM, this might cause unexpected behavior after wakeup.
 415  * Thus we save/restore these specified MSRs across suspend/resume
 416  * in order to work around it.
 417  *
 418  * For any further problematic BIOSen/platforms,
 419  * please add your own function similar to msr_initialize_bdw.
 420  */
 421 static int msr_initialize_bdw(const struct dmi_system_id *d)
 422 {
 423         /* Add any extra MSR ids into this array. */
 424         u32 bdw_msr_id[] = { MSR_IA32_THERM_CONTROL };
 425
 426         pr_info("x86/pm: %s detected, MSR saving is needed during suspending.\n", d->ident);
 427         return msr_init_context(bdw_msr_id, ARRAY_SIZE(bdw_msr_id));
 428 }
 429
 430 static struct dmi_system_id msr_save_dmi_table[] = {
 431         {
 432          .callback = msr_initialize_bdw,
 433          .ident = "BROADWELL BDX_EP",
 434          .matches = {
 435                 DMI_MATCH(DMI_PRODUCT_NAME, "GRANTLEY"),
 436                 DMI_MATCH(DMI_PRODUCT_VERSION, "E63448-400"),
 437                 },
 438         },
 439         {}
 440 };
 441
 442 static int pm_check_save_msr(void)
 443 {
 444         dmi_check_system(msr_save_dmi_table);
 445         return 0;
 446 }
 447
 448 device_initcall(pm_check_save_msr);