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/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/types.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/poll.h>
  17 #include <linux/delay.h>
  18 #include <linux/sysrq.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/irq.h>
  21 #include <linux/pm.h>
  22 #include <linux/device.h>
  23 #include <linux/suspend.h>
  24 #include <linux/acpi.h>
  25
  26 #include <asm/uaccess.h>
  27 #include <asm/acpi.h>
  28 #include <asm/tlbflush.h>
  29 #include <asm/processor.h>
  30
  31 static struct saved_context saved_context;
  32
  33 unsigned long saved_context_ebx;
  34 unsigned long saved_context_esp, saved_context_ebp;
  35 unsigned long saved_context_esi, saved_context_edi;
  36 unsigned long saved_context_eflags;
  37
  38 void __save_processor_state(struct saved_context *ctxt)
  39 {
  40         kernel_fpu_begin();
  41
  42         /*
  43          * descriptor tables
  44          */
  45         store_gdt(&ctxt->gdt_limit);
  46         store_idt(&ctxt->idt_limit);
  47         store_tr(ctxt->tr);
  48
  49         /*
  50          * segment registers
  51          */
  52         savesegment(es, ctxt->es);
  53         savesegment(fs, ctxt->fs);
  54         savesegment(gs, ctxt->gs);
  55         savesegment(ss, ctxt->ss);
  56
  57         /*
  58          * control registers
  59          */
  60         ctxt->cr0 = read_cr0();
  61         ctxt->cr2 = read_cr2();
  62         ctxt->cr3 = read_cr3();
  63         ctxt->cr4 = read_cr4();
  64 }
  65
  66 void save_processor_state(void)
  67 {
  68         __save_processor_state(&saved_context);
  69 }
  70
  71 static void
  72 do_fpu_end(void)
  73 {
  74         /* restore FPU regs if necessary */
  75         /* Do it out of line so that gcc does not move cr0 load to some stupid place */
  76         kernel_fpu_end();
  77         mxcsr_feature_mask_init();
  78 }
  79
  80
  81 static void fix_processor_context(void)
  82 {
  83         int cpu = smp_processor_id();
  84         struct tss_struct * t = &per_cpu(init_tss, cpu);
  85
  86         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. */
  87
  88         load_TR_desc();                         /* This does ltr */
  89         load_LDT(&current->active_mm->context); /* This does lldt */
  90
  91         /*
  92          * Now maybe reload the debug registers
  93          */
  94         if (current->thread.debugreg[7]){
  95                 set_debugreg(current->thread.debugreg[0], 0);
  96                 set_debugreg(current->thread.debugreg[1], 1);
  97                 set_debugreg(current->thread.debugreg[2], 2);
  98                 set_debugreg(current->thread.debugreg[3], 3);
  99                 /* no 4 and 5 */
 100                 set_debugreg(current->thread.debugreg[6], 6);
 101                 set_debugreg(current->thread.debugreg[7], 7);
 102         }
 103
 104 }
 105
 106 void __restore_processor_state(struct saved_context *ctxt)
 107 {
 108         /*
 109          * control registers
 110          */
 111         write_cr4(ctxt->cr4);
 112         write_cr3(ctxt->cr3);
 113         write_cr2(ctxt->cr2);
 114         write_cr2(ctxt->cr0);
 115
 116         /*
 117          * now restore the descriptor tables to their proper values
 118          * ltr is done i fix_processor_context().
 119          */
 120         load_gdt(&ctxt->gdt_limit);
 121         load_idt(&ctxt->idt_limit);
 122
 123         /*
 124          * segment registers
 125          */
 126         loadsegment(es, ctxt->es);
 127         loadsegment(fs, ctxt->fs);
 128         loadsegment(gs, ctxt->gs);
 129         loadsegment(ss, ctxt->ss);
 130
 131         /*
 132          * sysenter MSRs
 133          */
 134         if (boot_cpu_has(X86_FEATURE_SEP))
 135                 enable_sep_cpu();
 136
 137         fix_processor_context();
 138         do_fpu_end();
 139         mtrr_ap_init();
 140 }
 141
 142 void restore_processor_state(void)
 143 {
 144         __restore_processor_state(&saved_context);
 145 }
 146
 147 /* Needed by apm.c */
 148 EXPORT_SYMBOL(save_processor_state);
 149 EXPORT_SYMBOL(restore_processor_state);