root/arch/x86/kernel/efi_64.c

DEFINITIONS

1. early_mapping_set_exec
2. early_runtime_code_mapping_set_exec
3. efi_call_phys_prelog
4. efi_call_phys_epilog
5. efi_ioremap

/*
 * x86_64 specific EFI support functions
 * Based on Extensible Firmware Interface Specification version 1.0
 *
 * Copyright (C) 2005-2008 Intel Co.
 *      Fenghua Yu <fenghua.yu@intel.com>
 *      Bibo Mao <bibo.mao@intel.com>
 *      Chandramouli Narayanan <mouli@linux.intel.com>
 *      Huang Ying <ying.huang@intel.com>
 *
 * 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>

static pgd_t save_pgd __initdata;
static unsigned long efi_flags __initdata;

static void __init early_mapping_set_exec(unsigned long start,
                                          unsigned long end,
                                          int executable)
{
        unsigned long num_pages;

        start &= PMD_MASK;
        end = (end + PMD_SIZE - 1) & PMD_MASK;
        num_pages = (end - start) >> PAGE_SHIFT;
        if (executable)
                set_memory_x((unsigned long)__va(start), num_pages);
        else
                set_memory_nx((unsigned long)__va(start), num_pages);
}

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

        if (!(__supported_pte_mask & _PAGE_NX))
                return;

        /* Make EFI runtime 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) {
                        unsigned long end;
                        end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
                        early_mapping_set_exec(md->phys_addr, end, executable);
                }
        }
}

void __init efi_call_phys_prelog(void)
{
        unsigned long vaddress;

        early_runtime_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_runtime_code_mapping_set_exec(0);
}

void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size)
{
        static unsigned pages_mapped __initdata;
        unsigned i, pages;
        unsigned long offset;

        pages = PFN_UP(phys_addr + size) - PFN_DOWN(phys_addr);
        offset = phys_addr & ~PAGE_MASK;
        phys_addr &= PAGE_MASK;

        if (pages_mapped + pages > MAX_EFI_IO_PAGES)
                return NULL;

        for (i = 0; i < pages; i++) {
                __set_fixmap(FIX_EFI_IO_MAP_FIRST_PAGE - pages_mapped,
                             phys_addr, PAGE_KERNEL);
                phys_addr += PAGE_SIZE;
                pages_mapped++;
        }

        return (void __iomem *)__fix_to_virt(FIX_EFI_IO_MAP_FIRST_PAGE - \
                                             (pages_mapped - pages)) + offset;
}