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suspend_64.c

/*
 * Suspend support specific for i386.
 *
 * Distribute under GPLv2
 *
 * Copyright (c) 2002 Pavel Machek <pavel@suse.cz>
 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
 */

#include <linux/smp.h>
#include <linux/suspend.h>
#include <asm/proto.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mtrr.h>

/* References to section boundaries */
extern const void __nosave_begin, __nosave_end;

struct saved_context saved_context;

void __save_processor_state(struct saved_context *ctxt)
{
      kernel_fpu_begin();

      /*
       * descriptor tables
       */
      store_gdt((struct desc_ptr *)&ctxt->gdt_limit);
      store_idt((struct desc_ptr *)&ctxt->idt_limit);
      store_tr(ctxt->tr);

      /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
      /*
       * segment registers
       */
      asm volatile ("movw %%ds, %0" : "=m" (ctxt->ds));
      asm volatile ("movw %%es, %0" : "=m" (ctxt->es));
      asm volatile ("movw %%fs, %0" : "=m" (ctxt->fs));
      asm volatile ("movw %%gs, %0" : "=m" (ctxt->gs));
      asm volatile ("movw %%ss, %0" : "=m" (ctxt->ss));

      rdmsrl(MSR_FS_BASE, ctxt->fs_base);
      rdmsrl(MSR_GS_BASE, ctxt->gs_base);
      rdmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
      mtrr_save_fixed_ranges(NULL);

      /*
       * control registers 
       */
      rdmsrl(MSR_EFER, ctxt->efer);
      ctxt->cr0 = read_cr0();
      ctxt->cr2 = read_cr2();
      ctxt->cr3 = read_cr3();
      ctxt->cr4 = read_cr4();
      ctxt->cr8 = read_cr8();
}

void save_processor_state(void)
{
      __save_processor_state(&saved_context);
}

static void do_fpu_end(void)
{
      /*
       * Restore FPU regs if necessary
       */
      kernel_fpu_end();
}

void __restore_processor_state(struct saved_context *ctxt)
{
      /*
       * control registers
       */
      wrmsrl(MSR_EFER, ctxt->efer);
      write_cr8(ctxt->cr8);
      write_cr4(ctxt->cr4);
      write_cr3(ctxt->cr3);
      write_cr2(ctxt->cr2);
      write_cr0(ctxt->cr0);

      /*
       * now restore the descriptor tables to their proper values
       * ltr is done i fix_processor_context().
       */
      load_gdt((const struct desc_ptr *)&ctxt->gdt_limit);
      load_idt((const struct desc_ptr *)&ctxt->idt_limit);


      /*
       * segment registers
       */
      asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
      asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
      asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));
      load_gs_index(ctxt->gs);
      asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss));

      wrmsrl(MSR_FS_BASE, ctxt->fs_base);
      wrmsrl(MSR_GS_BASE, ctxt->gs_base);
      wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);

      fix_processor_context();

      do_fpu_end();
      mtrr_ap_init();
}

void restore_processor_state(void)
{
      __restore_processor_state(&saved_context);
}

void fix_processor_context(void)
{
      int cpu = smp_processor_id();
      struct tss_struct *t = &per_cpu(init_tss, cpu);

      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. */

      cpu_gdt(cpu)[GDT_ENTRY_TSS].type = 9;

      syscall_init();                         /* This sets MSR_*STAR and related */
      load_TR_desc();                     /* This does ltr */
      load_LDT(&current->active_mm->context);   /* This does lldt */

      /*
       * Now maybe reload the debug registers
       */
      if (current->thread.debugreg7){
                loaddebug(&current->thread, 0);
                loaddebug(&current->thread, 1);
                loaddebug(&current->thread, 2);
                loaddebug(&current->thread, 3);
                /* no 4 and 5 */
                loaddebug(&current->thread, 6);
                loaddebug(&current->thread, 7);
      }

}

#ifdef CONFIG_HIBERNATION
/* Defined in arch/x86_64/kernel/suspend_asm.S */
extern int restore_image(void);

/*
 * Address to jump to in the last phase of restore in order to get to the image
 * kernel's text (this value is passed in the image header).
 */
unsigned long restore_jump_address;

/*
 * Value of the cr3 register from before the hibernation (this value is passed
 * in the image header).
 */
unsigned long restore_cr3;

pgd_t *temp_level4_pgt;

void *relocated_restore_code;

static int res_phys_pud_init(pud_t *pud, unsigned long address, unsigned long end)
{
      long i, j;

      i = pud_index(address);
      pud = pud + i;
      for (; i < PTRS_PER_PUD; pud++, i++) {
            unsigned long paddr;
            pmd_t *pmd;

            paddr = address + i*PUD_SIZE;
            if (paddr >= end)
                  break;

            pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
            if (!pmd)
                  return -ENOMEM;
            set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
            for (j = 0; j < PTRS_PER_PMD; pmd++, j++, paddr += PMD_SIZE) {
                  unsigned long pe;

                  if (paddr >= end)
                        break;
                  pe = __PAGE_KERNEL_LARGE_EXEC | paddr;
                  pe &= __supported_pte_mask;
                  set_pmd(pmd, __pmd(pe));
            }
      }
      return 0;
}

static int set_up_temporary_mappings(void)
{
      unsigned long start, end, next;
      int error;

      temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC);
      if (!temp_level4_pgt)
            return -ENOMEM;

      /* It is safe to reuse the original kernel mapping */
      set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
            init_level4_pgt[pgd_index(__START_KERNEL_map)]);

      /* Set up the direct mapping from scratch */
      start = (unsigned long)pfn_to_kaddr(0);
      end = (unsigned long)pfn_to_kaddr(end_pfn);

      for (; start < end; start = next) {
            pud_t *pud = (pud_t *)get_safe_page(GFP_ATOMIC);
            if (!pud)
                  return -ENOMEM;
            next = start + PGDIR_SIZE;
            if (next > end)
                  next = end;
            if ((error = res_phys_pud_init(pud, __pa(start), __pa(next))))
                  return error;
            set_pgd(temp_level4_pgt + pgd_index(start),
                  mk_kernel_pgd(__pa(pud)));
      }
      return 0;
}

int swsusp_arch_resume(void)
{
      int error;

      /* We have got enough memory and from now on we cannot recover */
      if ((error = set_up_temporary_mappings()))
            return error;

      relocated_restore_code = (void *)get_safe_page(GFP_ATOMIC);
      if (!relocated_restore_code)
            return -ENOMEM;
      memcpy(relocated_restore_code, &core_restore_code,
             &restore_registers - &core_restore_code);

      restore_image();
      return 0;
}

/*
 *    pfn_is_nosave - check if given pfn is in the 'nosave' section
 */

int pfn_is_nosave(unsigned long pfn)
{
      unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
      unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
      return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}

struct restore_data_record {
      unsigned long jump_address;
      unsigned long cr3;
      unsigned long magic;
};

#define RESTORE_MAGIC   0x0123456789ABCDEFUL

/**
 *    arch_hibernation_header_save - populate the architecture specific part
 *          of a hibernation image header
 *    @addr: address to save the data at
 */
int arch_hibernation_header_save(void *addr, unsigned int max_size)
{
      struct restore_data_record *rdr = addr;

      if (max_size < sizeof(struct restore_data_record))
            return -EOVERFLOW;
      rdr->jump_address = restore_jump_address;
      rdr->cr3 = restore_cr3;
      rdr->magic = RESTORE_MAGIC;
      return 0;
}

/**
 *    arch_hibernation_header_restore - read the architecture specific data
 *          from the hibernation image header
 *    @addr: address to read the data from
 */
int arch_hibernation_header_restore(void *addr)
{
      struct restore_data_record *rdr = addr;

      restore_jump_address = rdr->jump_address;
      restore_cr3 = rdr->cr3;
      return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;
}
#endif /* CONFIG_HIBERNATION */

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