arch/x86/power/cpu_32.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 static 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_safe();
  49 }
  50
  51 /* Needed by apm.c */
  52 void save_processor_state(void)
  53 {
  54         __save_processor_state(&saved_context);
  55 }
  56 EXPORT_SYMBOL(save_processor_state);
  57
  58 static void do_fpu_end(void)
  59 {
  60         /*
  61          * Restore FPU regs if necessary.
  62          */
  63         kernel_fpu_end();
  64 }
  65
  66 static void fix_processor_context(void)
  67 {
  68         int cpu = smp_processor_id();
  69         struct tss_struct *t = &per_cpu(init_tss, cpu);
  70
  71         set_tss_desc(cpu, t);   /*
  72                                  * This just modifies memory; should not be
  73                                  * necessary. But... This is necessary, because
  74                                  * 386 hardware has concept of busy TSS or some
  75                                  * similar stupidity.
  76                                  */
  77
  78         load_TR_desc();                         /* This does ltr */
  79         load_LDT(&current->active_mm->context); /* This does lldt */
  80
  81         /*
  82          * Now maybe reload the debug registers
  83          */
  84         if (current->thread.debugreg7) {
  85                 set_debugreg(current->thread.debugreg0, 0);
  86                 set_debugreg(current->thread.debugreg1, 1);
  87                 set_debugreg(current->thread.debugreg2, 2);
  88                 set_debugreg(current->thread.debugreg3, 3);
  89                 /* no 4 and 5 */
  90                 set_debugreg(current->thread.debugreg6, 6);
  91                 set_debugreg(current->thread.debugreg7, 7);
  92         }
  93
  94 }
  95
  96 static void __restore_processor_state(struct saved_context *ctxt)
  97 {
  98         /*
  99          * control registers
 100          */
 101         /* cr4 was introduced in the Pentium CPU */
 102         if (ctxt->cr4)
 103                 write_cr4(ctxt->cr4);
 104         write_cr3(ctxt->cr3);
 105         write_cr2(ctxt->cr2);
 106         write_cr0(ctxt->cr0);
 107
 108         /*
 109          * now restore the descriptor tables to their proper values
 110          * ltr is done i fix_processor_context().
 111          */
 112         load_gdt(&ctxt->gdt);
 113         load_idt(&ctxt->idt);
 114
 115         /*
 116          * segment registers
 117          */
 118         loadsegment(es, ctxt->es);
 119         loadsegment(fs, ctxt->fs);
 120         loadsegment(gs, ctxt->gs);
 121         loadsegment(ss, ctxt->ss);
 122
 123         /*
 124          * sysenter MSRs
 125          */
 126         if (boot_cpu_has(X86_FEATURE_SEP))
 127                 enable_sep_cpu();
 128
 129         fix_processor_context();
 130         do_fpu_end();
 131         mtrr_ap_init();
 132         mcheck_init(&boot_cpu_data);
 133 }
 134
 135 /* Needed by apm.c */
 136 void restore_processor_state(void)
 137 {
 138         __restore_processor_state(&saved_context);
 139 }
 140 EXPORT_SYMBOL(restore_processor_state);