arch/i386/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/config.h>
  11 #include <linux/module.h>
  12 #include <linux/suspend.h>
  13 #include <asm/mtrr.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         kernel_fpu_begin();
  25
  26         /*
  27          * descriptor tables
  28          */
  29         store_gdt(&ctxt->gdt_limit);
  30         store_idt(&ctxt->idt_limit);
  31         store_tr(ctxt->tr);
  32
  33         /*
  34          * segment registers
  35          */
  36         savesegment(es, ctxt->es);
  37         savesegment(fs, ctxt->fs);
  38         savesegment(gs, ctxt->gs);
  39         savesegment(ss, ctxt->ss);
  40
  41         /*
  42          * control registers
  43          */
  44         ctxt->cr0 = read_cr0();
  45         ctxt->cr2 = read_cr2();
  46         ctxt->cr3 = read_cr3();
  47         ctxt->cr4 = read_cr4();
  48 }
  49
  50 void save_processor_state(void)
  51 {
  52         __save_processor_state(&saved_context);
  53 }
  54
  55 static void do_fpu_end(void)
  56 {
  57         /*
  58          * Restore FPU regs if necessary.
  59          */
  60         kernel_fpu_end();
  61 }
  62
  63 static void fix_processor_context(void)
  64 {
  65         int cpu = smp_processor_id();
  66         struct tss_struct * t = &per_cpu(init_tss, cpu);
  67
  68         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. */
  69
  70         load_TR_desc();                         /* This does ltr */
  71         load_LDT(&current->active_mm->context); /* This does lldt */
  72
  73         /*
  74          * Now maybe reload the debug registers
  75          */
  76         if (current->thread.debugreg[7]){
  77                 set_debugreg(current->thread.debugreg[0], 0);
  78                 set_debugreg(current->thread.debugreg[1], 1);
  79                 set_debugreg(current->thread.debugreg[2], 2);
  80                 set_debugreg(current->thread.debugreg[3], 3);
  81                 /* no 4 and 5 */
  82                 set_debugreg(current->thread.debugreg[6], 6);
  83                 set_debugreg(current->thread.debugreg[7], 7);
  84         }
  85
  86 }
  87
  88 void __restore_processor_state(struct saved_context *ctxt)
  89 {
  90         /*
  91          * control registers
  92          */
  93         write_cr4(ctxt->cr4);
  94         write_cr3(ctxt->cr3);
  95         write_cr2(ctxt->cr2);
  96         write_cr0(ctxt->cr0);
  97
  98         /*
  99          * now restore the descriptor tables to their proper values
 100          * ltr is done i fix_processor_context().
 101          */
 102         load_gdt(&ctxt->gdt_limit);
 103         load_idt(&ctxt->idt_limit);
 104
 105         /*
 106          * segment registers
 107          */
 108         loadsegment(es, ctxt->es);
 109         loadsegment(fs, ctxt->fs);
 110         loadsegment(gs, ctxt->gs);
 111         loadsegment(ss, ctxt->ss);
 112
 113         /*
 114          * sysenter MSRs
 115          */
 116         if (boot_cpu_has(X86_FEATURE_SEP))
 117                 enable_sep_cpu();
 118
 119         fix_processor_context();
 120         do_fpu_end();
 121         mtrr_ap_init();
 122         mcheck_init(&boot_cpu_data);
 123 }
 124
 125 void restore_processor_state(void)
 126 {
 127         __restore_processor_state(&saved_context);
 128 }
 129
 130 /* Needed by apm.c */
 131 EXPORT_SYMBOL(save_processor_state);
 132 EXPORT_SYMBOL(restore_processor_state);