hibernate_64.c

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/*
 * Hibernation support for x86-64
 *
 * Distribute under GPLv2
 *
 * Copyright (c) 2007 Rafael J. Wysocki <[email protected]>
 * Copyright (c) 2002 Pavel Machek <[email protected]>
 * Copyright (c) 2001 Patrick Mochel <[email protected]>
 */

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

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;
}

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;
}