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@suse.cz>
   8  * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
   9  */
  10
  11 #include <linux/suspend.h>
  12 #include <linux/smp.h>
  13
  14 #include <asm/pgtable.h>
  15 #include <asm/proto.h>
  16 #include <asm/mtrr.h>
  17 #include <asm/page.h>
  18 #include <asm/mce.h>
  19 #include <asm/xcr.h>
  20 #include <asm/suspend.h>
  21 #include <asm/debugreg.h>
  22
  23 #ifdef CONFIG_X86_32
  24 static struct saved_context saved_context;
  25
  26 unsigned long saved_context_ebx;
  27 unsigned long saved_context_esp, saved_context_ebp;
  28 unsigned long saved_context_esi, saved_context_edi;
  29 unsigned long saved_context_eflags;
  30 #else
  31 /* CONFIG_X86_64 */
  32 struct saved_context saved_context;
  33 #endif
  34
  35 /**
  36  *      __save_processor_state - save CPU registers before creating a
  37  *              hibernation image and before restoring the memory state from it
  38  *      @ctxt - structure to store the registers contents in
  39  *
  40  *      NOTE: If there is a CPU register the modification of which by the
  41  *      boot kernel (ie. the kernel used for loading the hibernation image)
  42  *      might affect the operations of the restored target kernel (ie. the one
  43  *      saved in the hibernation image), then its contents must be saved by this
  44  *      function.  In other words, if kernel A is hibernated and different
  45  *      kernel B is used for loading the hibernation image into memory, the
  46  *      kernel A's __save_processor_state() function must save all registers
  47  *      needed by kernel A, so that it can operate correctly after the resume
  48  *      regardless of what kernel B does in the meantime.
  49  */
  50 static void __save_processor_state(struct saved_context *ctxt)
  51 {
  52 #ifdef CONFIG_X86_32
  53         mtrr_save_fixed_ranges(NULL);
  54 #endif
  55         kernel_fpu_begin();
  56
  57         /*
  58          * descriptor tables
  59          */
  60 #ifdef CONFIG_X86_32
  61         store_gdt(&ctxt->gdt);
  62         store_idt(&ctxt->idt);
  63 #else
  64 /* CONFIG_X86_64 */
  65         store_gdt((struct desc_ptr *)&ctxt->gdt_limit);
  66         store_idt((struct desc_ptr *)&ctxt->idt_limit);
  67 #endif
  68         store_tr(ctxt->tr);
  69
  70         /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
  71         /*
  72          * segment registers
  73          */
  74 #ifdef CONFIG_X86_32
  75         savesegment(es, ctxt->es);
  76         savesegment(fs, ctxt->fs);
  77         savesegment(gs, ctxt->gs);
  78         savesegment(ss, ctxt->ss);
  79 #else
  80 /* CONFIG_X86_64 */
  81         asm volatile ("movw %%ds, %0" : "=m" (ctxt->ds));
  82         asm volatile ("movw %%es, %0" : "=m" (ctxt->es));
  83         asm volatile ("movw %%fs, %0" : "=m" (ctxt->fs));
  84         asm volatile ("movw %%gs, %0" : "=m" (ctxt->gs));
  85         asm volatile ("movw %%ss, %0" : "=m" (ctxt->ss));
  86
  87         rdmsrl(MSR_FS_BASE, ctxt->fs_base);
  88         rdmsrl(MSR_GS_BASE, ctxt->gs_base);
  89         rdmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
  90         mtrr_save_fixed_ranges(NULL);
  91
  92         rdmsrl(MSR_EFER, ctxt->efer);
  93 #endif
  94
  95         /*
  96          * control registers
  97          */
  98         ctxt->cr0 = read_cr0();
  99         ctxt->cr2 = read_cr2();
 100         ctxt->cr3 = read_cr3();
 101 #ifdef CONFIG_X86_32
 102         ctxt->cr4 = read_cr4_safe();
 103 #else
 104 /* CONFIG_X86_64 */
 105         ctxt->cr4 = read_cr4();
 106         ctxt->cr8 = read_cr8();
 107 #endif
 108 }
 109
 110 /* Needed by apm.c */
 111 void save_processor_state(void)
 112 {
 113         __save_processor_state(&saved_context);
 114 }
 115 #ifdef CONFIG_X86_32
 116 EXPORT_SYMBOL(save_processor_state);
 117 #endif
 118
 119 static void do_fpu_end(void)
 120 {
 121         /*
 122          * Restore FPU regs if necessary.
 123          */
 124         kernel_fpu_end();
 125 }
 126
 127 static void fix_processor_context(void)
 128 {
 129         int cpu = smp_processor_id();
 130         struct tss_struct *t = &per_cpu(init_tss, cpu);
 131
 132         set_tss_desc(cpu, t);   /*
 133                                  * This just modifies memory; should not be
 134                                  * necessary. But... This is necessary, because
 135                                  * 386 hardware has concept of busy TSS or some
 136                                  * similar stupidity.
 137                                  */
 138
 139 #ifdef CONFIG_X86_64
 140         get_cpu_gdt_table(cpu)[GDT_ENTRY_TSS].type = 9;
 141
 142         syscall_init();                         /* This sets MSR_*STAR and related */
 143 #endif
 144         load_TR_desc();                         /* This does ltr */
 145         load_LDT(&current->active_mm->context); /* This does lldt */
 146 }
 147
 148 /**
 149  *      __restore_processor_state - restore the contents of CPU registers saved
 150  *              by __save_processor_state()
 151  *      @ctxt - structure to load the registers contents from
 152  */
 153 static void __restore_processor_state(struct saved_context *ctxt)
 154 {
 155         /*
 156          * control registers
 157          */
 158         /* cr4 was introduced in the Pentium CPU */
 159 #ifdef CONFIG_X86_32
 160         if (ctxt->cr4)
 161                 write_cr4(ctxt->cr4);
 162 #else
 163 /* CONFIG X86_64 */
 164         wrmsrl(MSR_EFER, ctxt->efer);
 165         write_cr8(ctxt->cr8);
 166         write_cr4(ctxt->cr4);
 167 #endif
 168         write_cr3(ctxt->cr3);
 169         write_cr2(ctxt->cr2);
 170         write_cr0(ctxt->cr0);
 171
 172         /*
 173          * now restore the descriptor tables to their proper values
 174          * ltr is done i fix_processor_context().
 175          */
 176 #ifdef CONFIG_X86_32
 177         load_gdt(&ctxt->gdt);
 178         load_idt(&ctxt->idt);
 179 #else
 180 /* CONFIG_X86_64 */
 181         load_gdt((const struct desc_ptr *)&ctxt->gdt_limit);
 182         load_idt((const struct desc_ptr *)&ctxt->idt_limit);
 183 #endif
 184
 185         /*
 186          * segment registers
 187          */
 188 #ifdef CONFIG_X86_32
 189         loadsegment(es, ctxt->es);
 190         loadsegment(fs, ctxt->fs);
 191         loadsegment(gs, ctxt->gs);
 192         loadsegment(ss, ctxt->ss);
 193
 194         /*
 195          * sysenter MSRs
 196          */
 197         if (boot_cpu_has(X86_FEATURE_SEP))
 198                 enable_sep_cpu();
 199 #else
 200 /* CONFIG_X86_64 */
 201         asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
 202         asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
 203         asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));
 204         load_gs_index(ctxt->gs);
 205         asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss));
 206
 207         wrmsrl(MSR_FS_BASE, ctxt->fs_base);
 208         wrmsrl(MSR_GS_BASE, ctxt->gs_base);
 209         wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
 210 #endif
 211
 212         /*
 213          * restore XCR0 for xsave capable cpu's.
 214          */
 215         if (cpu_has_xsave)
 216                 xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
 217
 218         fix_processor_context();
 219
 220         do_fpu_end();
 221         mtrr_bp_restore();
 222 }
 223
 224 /* Needed by apm.c */
 225 void restore_processor_state(void)
 226 {
 227         __restore_processor_state(&saved_context);
 228 }
 229 #ifdef CONFIG_X86_32
 230 EXPORT_SYMBOL(restore_processor_state);
 231 #endif