efi_64.c

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/*
 * x86_64 specific EFI support functions
 * Based on Extensible Firmware Interface Specification version 1.0
 *
 * Copyright (C) 2005-2008 Intel Co.
 *  Fenghua Yu <[email protected]>
 *  Bibo Mao <[email protected]>
 *  Chandramouli Narayanan <[email protected]>
 *  Huang Ying <[email protected]>
 *
 * Code to convert EFI to E820 map has been implemented in elilo bootloader
 * based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
 * is setup appropriately for EFI runtime code.
 * - mouli 06/14/2007.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/reboot.h>

#include <asm/setup.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/proto.h>
#include <asm/efi.h>
#include <asm/cacheflush.h>
#include <asm/fixmap.h>

static pgd_t save_pgd __initdata;
static unsigned long efi_flags __initdata;

static void __init early_code_mapping_set_exec(int executable)
{
    efi_memory_desc_t *md;
    void *p;

    if (!(__supported_pte_mask & _PAGE_NX))
        return;

    /* Make EFI service code area executable */
    for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
        md = p;
        if (md->type == EFI_RUNTIME_SERVICES_CODE ||
            md->type == EFI_BOOT_SERVICES_CODE)
            efi_set_executable(md, executable);
    }
}

void __init efi_call_phys_prelog(void)
{
    unsigned long vaddress;

    early_code_mapping_set_exec(1);
    local_irq_save(efi_flags);
    vaddress = (unsigned long)__va(0x0UL);
    save_pgd = *pgd_offset_k(0x0UL);
    set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
    __flush_tlb_all();
}

void __init efi_call_phys_epilog(void)
{
    /*
     * After the lock is released, the original page table is restored.
     */
    set_pgd(pgd_offset_k(0x0UL), save_pgd);
    __flush_tlb_all();
    local_irq_restore(efi_flags);
    early_code_mapping_set_exec(0);
}

void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
                 u32 type, u64 attribute)
{
    unsigned long last_map_pfn;

    if (type == EFI_MEMORY_MAPPED_IO)
        return ioremap(phys_addr, size);

    last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
    if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
        unsigned long top = last_map_pfn << PAGE_SHIFT;
        efi_ioremap(top, size - (top - phys_addr), type, attribute);
    }

    if (!(attribute & EFI_MEMORY_WB))
        efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);

    return (void __iomem *)__va(phys_addr);
}