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cpu.c

/*
 * Suspend support specific for i386.
 *
 * Distribute under GPLv2
 *
 * Copyright (c) 2002 Pavel Machek <pavel@suse.cz>
 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
 */

#include <linux/module.h>
#include <linux/suspend.h>
#include <asm/mtrr.h>
#include <asm/mce.h>

static struct saved_context saved_context;

unsigned long saved_context_ebx;
unsigned long saved_context_esp, saved_context_ebp;
unsigned long saved_context_esi, saved_context_edi;
unsigned long saved_context_eflags;

void __save_processor_state(struct saved_context *ctxt)
{
      mtrr_save_fixed_ranges(NULL);
      kernel_fpu_begin();

      /*
       * descriptor tables
       */
      store_gdt(&ctxt->gdt);
      store_idt(&ctxt->idt);
      store_tr(ctxt->tr);

      /*
       * segment registers
       */
      savesegment(es, ctxt->es);
      savesegment(fs, ctxt->fs);
      savesegment(gs, ctxt->gs);
      savesegment(ss, ctxt->ss);

      /*
       * control registers 
       */
      ctxt->cr0 = read_cr0();
      ctxt->cr2 = read_cr2();
      ctxt->cr3 = read_cr3();
      ctxt->cr4 = read_cr4();
}

void save_processor_state(void)
{
      __save_processor_state(&saved_context);
}

static void do_fpu_end(void)
{
      /*
       * Restore FPU regs if necessary.
       */
      kernel_fpu_end();
}

static void fix_processor_context(void)
{
      int cpu = smp_processor_id();
      struct tss_struct * t = &per_cpu(init_tss, cpu);

      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. */

      load_TR_desc();                     /* This does ltr */
      load_LDT(&current->active_mm->context);   /* This does lldt */

      /*
       * Now maybe reload the debug registers
       */
      if (current->thread.debugreg[7]){
            set_debugreg(current->thread.debugreg[0], 0);
            set_debugreg(current->thread.debugreg[1], 1);
            set_debugreg(current->thread.debugreg[2], 2);
            set_debugreg(current->thread.debugreg[3], 3);
            /* no 4 and 5 */
            set_debugreg(current->thread.debugreg[6], 6);
            set_debugreg(current->thread.debugreg[7], 7);
      }

}

void __restore_processor_state(struct saved_context *ctxt)
{
      /*
       * control registers
       */
      write_cr4(ctxt->cr4);
      write_cr3(ctxt->cr3);
      write_cr2(ctxt->cr2);
      write_cr0(ctxt->cr0);

      /*
       * now restore the descriptor tables to their proper values
       * ltr is done i fix_processor_context().
       */
      load_gdt(&ctxt->gdt);
      load_idt(&ctxt->idt);

      /*
       * segment registers
       */
      loadsegment(es, ctxt->es);
      loadsegment(fs, ctxt->fs);
      loadsegment(gs, ctxt->gs);
      loadsegment(ss, ctxt->ss);

      /*
       * sysenter MSRs
       */
      if (boot_cpu_has(X86_FEATURE_SEP))
            enable_sep_cpu();

      fix_processor_context();
      do_fpu_end();
      mtrr_ap_init();
      mcheck_init(&boot_cpu_data);
}

void restore_processor_state(void)
{
      __restore_processor_state(&saved_context);
}

/* Needed by apm.c */
EXPORT_SYMBOL(save_processor_state);
EXPORT_SYMBOL(restore_processor_state);

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