linux/arch/x86/kernel/efi_64.c

135 lines
3.3 KiB
C

/*
* 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>
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)
{
pte_t *kpte;
unsigned int level;
while (start < end) {
kpte = lookup_address((unsigned long)__va(start), &level);
BUG_ON(!kpte);
if (executable)
set_pte(kpte, pte_mkexec(*kpte));
else
set_pte(kpte, __pte((pte_val(*kpte) | _PAGE_NX) & \
__supported_pte_mask));
if (level == 4)
start = (start + PMD_SIZE) & PMD_MASK;
else
start = (start + PAGE_SIZE) & PAGE_MASK;
}
}
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 << PAGE_SHIFT);
early_mapping_set_exec(md->phys_addr, end, executable);
}
}
}
void __init efi_call_phys_prelog(void)
{
unsigned long vaddress;
local_irq_save(efi_flags);
early_runtime_code_mapping_set_exec(1);
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);
early_runtime_code_mapping_set_exec(0);
__flush_tlb_all();
local_irq_restore(efi_flags);
}
void __init efi_reserve_bootmem(void)
{
reserve_bootmem_generic((unsigned long)memmap.phys_map,
memmap.nr_map * memmap.desc_size);
}
void __iomem * __init efi_ioremap(unsigned long offset,
unsigned long size)
{
static unsigned pages_mapped;
unsigned long last_addr;
unsigned i, pages;
last_addr = offset + size - 1;
offset &= PAGE_MASK;
pages = (PAGE_ALIGN(last_addr) - offset) >> PAGE_SHIFT;
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,
offset, PAGE_KERNEL_EXEC_NOCACHE);
offset += PAGE_SIZE;
pages_mapped++;
}
return (void __iomem *)__fix_to_virt(FIX_EFI_IO_MAP_FIRST_PAGE - \
(pages_mapped - pages));
}