arch/x86/power/cpu.c

   1 /*
   2  * Suspend support specific for i386.
   3  *
   4  * Distribute under GPLv2
   5  *
   6  * Copyright (c) 2002 Pavel Machek <pavel@suse.cz>
   7  * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/suspend.h>
  12 #include <asm/mtrr.h>
  13 #include <asm/mce.h>
  14
  15 static struct saved_context saved_context;
  16
  17 unsigned long saved_context_ebx;
  18 unsigned long saved_context_esp, saved_context_ebp;
  19 unsigned long saved_context_esi, saved_context_edi;
  20 unsigned long saved_context_eflags;
  21
  22 void __save_processor_state(struct saved_context *ctxt)
  23 {
  24         mtrr_save_fixed_ranges(NULL);
  25         kernel_fpu_begin();
  26
  27         /*
  28          * descriptor tables
  29          */
  30         store_gdt(&ctxt->gdt);
  31         store_idt(&ctxt->idt);
  32         store_tr(ctxt->tr);
  33
  34         /*
  35          * segment registers
  36          */
  37         savesegment(es, ctxt->es);
  38         savesegment(fs, ctxt->fs);
  39         savesegment(gs, ctxt->gs);
  40         savesegment(ss, ctxt->ss);
  41
  42         /*
  43          * control registers
  44          */
  45         ctxt->cr0 = read_cr0();
  46         ctxt->cr2 = read_cr2();
  47         ctxt->cr3 = read_cr3();
  48         ctxt->cr4 = read_cr4();
  49 }
  50
  51 void save_processor_state(void)
  52 {
  53         __save_processor_state(&saved_context);
  54 }
  55
  56 static void do_fpu_end(void)
  57 {
  58         /*
  59          * Restore FPU regs if necessary.
  60          */
  61         kernel_fpu_end();
  62 }
  63
  64 static void fix_processor_context(void)
  65 {
  66         int cpu = smp_processor_id();
  67         struct tss_struct * t = &per_cpu(init_tss, cpu);
  68
  69         set_tss_desc(cpu,t);    /* This just modifies memory; should not be necessary. But... This is necessary, because 386 hardware has concept of busy TSS or some similar stupidity. */
  70
  71         load_TR_desc();                         /* This does ltr */
  72         load_LDT(&current->active_mm->context); /* This does lldt */
  73
  74         /*
  75          * Now maybe reload the debug registers
  76          */
  77         if (current->thread.debugreg[7]){
  78                 set_debugreg(current->thread.debugreg[0], 0);
  79                 set_debugreg(current->thread.debugreg[1], 1);
  80                 set_debugreg(current->thread.debugreg[2], 2);
  81                 set_debugreg(current->thread.debugreg[3], 3);
  82                 /* no 4 and 5 */
  83                 set_debugreg(current->thread.debugreg[6], 6);
  84                 set_debugreg(current->thread.debugreg[7], 7);
  85         }
  86
  87 }
  88
  89 void __restore_processor_state(struct saved_context *ctxt)
  90 {
  91         /*
  92          * control registers
  93          */
  94         write_cr4(ctxt->cr4);
  95         write_cr3(ctxt->cr3);
  96         write_cr2(ctxt->cr2);
  97         write_cr0(ctxt->cr0);
  98
  99         /*
 100          * now restore the descriptor tables to their proper values
 101          * ltr is done i fix_processor_context().
 102          */
 103         load_gdt(&ctxt->gdt);
 104         load_idt(&ctxt->idt);
 105
 106         /*
 107          * segment registers
 108          */
 109         loadsegment(es, ctxt->es);
 110         loadsegment(fs, ctxt->fs);
 111         loadsegment(gs, ctxt->gs);
 112         loadsegment(ss, ctxt->ss);
 113
 114         /*
 115          * sysenter MSRs
 116          */
 117         if (boot_cpu_has(X86_FEATURE_SEP))
 118                 enable_sep_cpu();
 119
 120         fix_processor_context();
 121         do_fpu_end();
 122         mtrr_ap_init();
 123         mcheck_init(&boot_cpu_data);
 124 }
 125
 126 void restore_processor_state(void)
 127 {
 128         __restore_processor_state(&saved_context);
 129 }
 130
 131 /* Needed by apm.c */
 132 EXPORT_SYMBOL(save_processor_state);
 133 EXPORT_SYMBOL(restore_processor_state);