linux/arch/x86/power/cpu_32.c
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   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
  16static struct saved_context saved_context;
  17
  18unsigned long saved_context_ebx;
  19unsigned long saved_context_esp, saved_context_ebp;
  20unsigned long saved_context_esi, saved_context_edi;
  21unsigned long saved_context_eflags;
  22
  23static void __save_processor_state(struct saved_context *ctxt)
  24{
  25        mtrr_save_fixed_ranges(NULL);
  26        kernel_fpu_begin();
  27
  28        /*
  29         * descriptor tables
  30         */
  31        store_gdt(&ctxt->gdt);
  32        store_idt(&ctxt->idt);
  33        store_tr(ctxt->tr);
  34
  35        /*
  36         * segment registers
  37         */
  38        savesegment(es, ctxt->es);
  39        savesegment(fs, ctxt->fs);
  40        savesegment(gs, ctxt->gs);
  41        savesegment(ss, ctxt->ss);
  42
  43        /*
  44         * control registers
  45         */
  46        ctxt->cr0 = read_cr0();
  47        ctxt->cr2 = read_cr2();
  48        ctxt->cr3 = read_cr3();
  49        ctxt->cr4 = read_cr4_safe();
  50}
  51
  52/* Needed by apm.c */
  53void save_processor_state(void)
  54{
  55        __save_processor_state(&saved_context);
  56}
  57EXPORT_SYMBOL(save_processor_state);
  58
  59static void do_fpu_end(void)
  60{
  61        /*
  62         * Restore FPU regs if necessary.
  63         */
  64        kernel_fpu_end();
  65}
  66
  67static void fix_processor_context(void)
  68{
  69        int cpu = smp_processor_id();
  70        struct tss_struct *t = &per_cpu(init_tss, cpu);
  71
  72        set_tss_desc(cpu, t);   /*
  73                                 * This just modifies memory; should not be
  74                                 * necessary. But... This is necessary, because
  75                                 * 386 hardware has concept of busy TSS or some
  76                                 * similar stupidity.
  77                                 */
  78
  79        load_TR_desc();                         /* This does ltr */
  80        load_LDT(&current->active_mm->context); /* This does lldt */
  81
  82        /*
  83         * Now maybe reload the debug registers
  84         */
  85        if (current->thread.debugreg7) {
  86                set_debugreg(current->thread.debugreg0, 0);
  87                set_debugreg(current->thread.debugreg1, 1);
  88                set_debugreg(current->thread.debugreg2, 2);
  89                set_debugreg(current->thread.debugreg3, 3);
  90                /* no 4 and 5 */
  91                set_debugreg(current->thread.debugreg6, 6);
  92                set_debugreg(current->thread.debugreg7, 7);
  93        }
  94
  95}
  96
  97static void __restore_processor_state(struct saved_context *ctxt)
  98{
  99        /*
 100         * control registers
 101         */
 102        /* cr4 was introduced in the Pentium CPU */
 103        if (ctxt->cr4)
 104                write_cr4(ctxt->cr4);
 105        write_cr3(ctxt->cr3);
 106        write_cr2(ctxt->cr2);
 107        write_cr0(ctxt->cr0);
 108
 109        /*
 110         * now restore the descriptor tables to their proper values
 111         * ltr is done i fix_processor_context().
 112         */
 113        load_gdt(&ctxt->gdt);
 114        load_idt(&ctxt->idt);
 115
 116        /*
 117         * segment registers
 118         */
 119        loadsegment(es, ctxt->es);
 120        loadsegment(fs, ctxt->fs);
 121        loadsegment(gs, ctxt->gs);
 122        loadsegment(ss, ctxt->ss);
 123
 124        /*
 125         * sysenter MSRs
 126         */
 127        if (boot_cpu_has(X86_FEATURE_SEP))
 128                enable_sep_cpu();
 129
 130        /*
 131         * restore XCR0 for xsave capable cpu's.
 132         */
 133        if (cpu_has_xsave)
 134                xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
 135
 136        fix_processor_context();
 137        do_fpu_end();
 138        mtrr_ap_init();
 139        mcheck_init(&boot_cpu_data);
 140}
 141
 142/* Needed by apm.c */
 143void restore_processor_state(void)
 144{
 145        __restore_processor_state(&saved_context);
 146}
 147EXPORT_SYMBOL(restore_processor_state);
 148