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 #include <asm/xcr.h>
  15 #include <asm/suspend.h>
  16
  17 static struct saved_context saved_context;
  18
  19 unsigned long saved_context_ebx;
  20 unsigned long saved_context_esp, saved_context_ebp;
  21 unsigned long saved_context_esi, saved_context_edi;
  22 unsigned long saved_context_eflags;
  23
  24 static void __save_processor_state(struct saved_context *ctxt)
  25 {
  26         mtrr_save_fixed_ranges(NULL);
  27         kernel_fpu_begin();
  28
  29         /*
  30          * descriptor tables
  31          */
  32         store_gdt(&ctxt->gdt);
  33         store_idt(&ctxt->idt);
  34         store_tr(ctxt->tr);
  35
  36         /*
  37          * segment registers
  38          */
  39         savesegment(es, ctxt->es);
  40         savesegment(fs, ctxt->fs);
  41         savesegment(gs, ctxt->gs);
  42         savesegment(ss, ctxt->ss);
  43
  44         /*
  45          * control registers
  46          */
  47         ctxt->cr0 = read_cr0();
  48         ctxt->cr2 = read_cr2();
  49         ctxt->cr3 = read_cr3();
  50         ctxt->cr4 = read_cr4_safe();
  51 }
  52
  53 /* Needed by apm.c */
  54 void save_processor_state(void)
  55 {
  56         __save_processor_state(&saved_context);
  57 }
  58 EXPORT_SYMBOL(save_processor_state);
  59
  60 static void do_fpu_end(void)
  61 {
  62         /*
  63          * Restore FPU regs if necessary.
  64          */
  65         kernel_fpu_end();
  66 }
  67
  68 static void fix_processor_context(void)
  69 {
  70         int cpu = smp_processor_id();
  71         struct tss_struct *t = &per_cpu(init_tss, cpu);
  72
  73         set_tss_desc(cpu, t);   /*
  74                                  * This just modifies memory; should not be
  75                                  * necessary. But... This is necessary, because
  76                                  * 386 hardware has concept of busy TSS or some
  77                                  * similar stupidity.
  78                                  */
  79
  80         load_TR_desc();                         /* This does ltr */
  81         load_LDT(&current->active_mm->context); /* This does lldt */
  82
  83         /*
  84          * Now maybe reload the debug registers
  85          */
  86         if (current->thread.debugreg7) {
  87                 set_debugreg(current->thread.debugreg0, 0);
  88                 set_debugreg(current->thread.debugreg1, 1);
  89                 set_debugreg(current->thread.debugreg2, 2);
  90                 set_debugreg(current->thread.debugreg3, 3);
  91                 /* no 4 and 5 */
  92                 set_debugreg(current->thread.debugreg6, 6);
  93                 set_debugreg(current->thread.debugreg7, 7);
  94         }
  95
  96 }
  97
  98 static void __restore_processor_state(struct saved_context *ctxt)
  99 {
 100         /*
 101          * control registers
 102          */
 103         /* cr4 was introduced in the Pentium CPU */
 104         if (ctxt->cr4)
 105                 write_cr4(ctxt->cr4);
 106         write_cr3(ctxt->cr3);
 107         write_cr2(ctxt->cr2);
 108         write_cr0(ctxt->cr0);
 109
 110         /*
 111          * now restore the descriptor tables to their proper values
 112          * ltr is done i fix_processor_context().
 113          */
 114         load_gdt(&ctxt->gdt);
 115         load_idt(&ctxt->idt);
 116
 117         /*
 118          * segment registers
 119          */
 120         loadsegment(es, ctxt->es);
 121         loadsegment(fs, ctxt->fs);
 122         loadsegment(gs, ctxt->gs);
 123         loadsegment(ss, ctxt->ss);
 124
 125         /*
 126          * sysenter MSRs
 127          */
 128         if (boot_cpu_has(X86_FEATURE_SEP))
 129                 enable_sep_cpu();
 130
 131         /*
 132          * restore XCR0 for xsave capable cpu's.
 133          */
 134         if (cpu_has_xsave)
 135                 xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
 136
 137         fix_processor_context();
 138         do_fpu_end();
 139         mtrr_ap_init();
 140         mcheck_init(&boot_cpu_data);
 141 }
 142
 143 /* Needed by apm.c */
 144 void restore_processor_state(void)
 145 {
 146         __restore_processor_state(&saved_context);
 147 }
 148 EXPORT_SYMBOL(restore_processor_state);