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
  14 static struct saved_context saved_context;
  15
  16 unsigned long saved_context_ebx;
  17 unsigned long saved_context_esp, saved_context_ebp;
  18 unsigned long saved_context_esi, saved_context_edi;
  19 unsigned long saved_context_eflags;
  20
  21 void __save_processor_state(struct saved_context *ctxt)
  22 {
  23         kernel_fpu_begin();
  24
  25         /*
  26          * descriptor tables
  27          */
  28         store_gdt(&ctxt->gdt_limit);
  29         store_idt(&ctxt->idt_limit);
  30         store_tr(ctxt->tr);
  31
  32         /*
  33          * segment registers
  34          */
  35         savesegment(es, ctxt->es);
  36         savesegment(fs, ctxt->fs);
  37         savesegment(gs, ctxt->gs);
  38         savesegment(ss, ctxt->ss);
  39
  40         /*
  41          * control registers
  42          */
  43         ctxt->cr0 = read_cr0();
  44         ctxt->cr2 = read_cr2();
  45         ctxt->cr3 = read_cr3();
  46         ctxt->cr4 = read_cr4();
  47 }
  48
  49 void save_processor_state(void)
  50 {
  51         __save_processor_state(&saved_context);
  52 }
  53
  54 static void do_fpu_end(void)
  55 {
  56         /*
  57          * Restore FPU regs if necessary.
  58          */
  59         kernel_fpu_end();
  60 }
  61
  62 static void fix_processor_context(void)
  63 {
  64         int cpu = smp_processor_id();
  65         struct tss_struct * t = &per_cpu(init_tss, cpu);
  66
  67         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. */
  68
  69         load_TR_desc();                         /* This does ltr */
  70         load_LDT(&current->active_mm->context); /* This does lldt */
  71
  72         /*
  73          * Now maybe reload the debug registers
  74          */
  75         if (current->thread.debugreg[7]){
  76                 set_debugreg(current->thread.debugreg[0], 0);
  77                 set_debugreg(current->thread.debugreg[1], 1);
  78                 set_debugreg(current->thread.debugreg[2], 2);
  79                 set_debugreg(current->thread.debugreg[3], 3);
  80                 /* no 4 and 5 */
  81                 set_debugreg(current->thread.debugreg[6], 6);
  82                 set_debugreg(current->thread.debugreg[7], 7);
  83         }
  84
  85 }
  86
  87 void __restore_processor_state(struct saved_context *ctxt)
  88 {
  89         /*
  90          * control registers
  91          */
  92         write_cr4(ctxt->cr4);
  93         write_cr3(ctxt->cr3);
  94         write_cr2(ctxt->cr2);
  95         write_cr0(ctxt->cr0);
  96
  97         /*
  98          * now restore the descriptor tables to their proper values
  99          * ltr is done i fix_processor_context().
 100          */
 101         load_gdt(&ctxt->gdt_limit);
 102         load_idt(&ctxt->idt_limit);
 103
 104         /*
 105          * segment registers
 106          */
 107         loadsegment(es, ctxt->es);
 108         loadsegment(fs, ctxt->fs);
 109         loadsegment(gs, ctxt->gs);
 110         loadsegment(ss, ctxt->ss);
 111
 112         /*
 113          * sysenter MSRs
 114          */
 115         if (boot_cpu_has(X86_FEATURE_SEP))
 116                 enable_sep_cpu();
 117
 118         fix_processor_context();
 119         do_fpu_end();
 120         mtrr_ap_init();
 121         mcheck_init(&boot_cpu_data);
 122 }
 123
 124 void restore_processor_state(void)
 125 {
 126         __restore_processor_state(&saved_context);
 127 }
 128
 129 /* Needed by apm.c */
 130 EXPORT_SYMBOL(save_processor_state);
 131 EXPORT_SYMBOL(restore_processor_state);