root/arch/x86/power/hibernate_64.c

DEFINITIONS

1. res_phys_pud_init
2. set_up_temporary_mappings
3. swsusp_arch_resume
4. pfn_is_nosave
5. arch_hibernation_header_save
6. arch_hibernation_header_restore

/*
 * Hibernation support for x86-64
 *
 * Distribute under GPLv2
 *
 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
 * 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;

/* Defined in hibernate_asm_64.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(max_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;
}