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/*
* Extensible Firmware Interface
*
* Based on Extensible Firmware Interface Specification version 1.0
*
* Copyright (C) 1999 VA Linux Systems
* Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
* Copyright (C) 1999-2002 Hewlett-Packard Co.
* David Mosberger-Tang <davidm@hpl.hp.com>
* Stephane Eranian <eranian@hpl.hp.com>
*
* All EFI Runtime Services are not implemented yet as EFI only
* supports physical mode addressing on SoftSDV. This is to be fixed
* in a future version. --drummond 1999-07-20
*
* Implemented EFI runtime services and virtual mode calls. --davidm
*
* Goutham Rao: <goutham.rao@intel.com>
* Skip non-WB memory and ignore empty memory ranges.
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/efi.h>
#include <asm/io.h>
#include <asm/desc.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/efi.h>
/*
* To make EFI call EFI runtime service in physical addressing mode we need
* prelog/epilog before/after the invocation to disable interrupt, to
* claim EFI runtime service handler exclusively and to duplicate a memory in
* low memory space say 0 - 3G.
*/
static unsigned long efi_rt_eflags;
static pgd_t efi_bak_pg_dir_pointer[2];
void efi_call_phys_prelog(void)
{
unsigned long cr4;
unsigned long temp;
struct desc_ptr gdt_descr;
local_irq_save(efi_rt_eflags);
/*
* If I don't have PAE, I should just duplicate two entries in page
* directory. If I have PAE, I just need to duplicate one entry in
* page directory.
*/
cr4 = read_cr4_safe();
if (cr4 & X86_CR4_PAE) {
efi_bak_pg_dir_pointer[0].pgd =
swapper_pg_dir[pgd_index(0)].pgd;
swapper_pg_dir[0].pgd =
swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
} else {
efi_bak_pg_dir_pointer[0].pgd =
swapper_pg_dir[pgd_index(0)].pgd;
efi_bak_pg_dir_pointer[1].pgd =
swapper_pg_dir[pgd_index(0x400000)].pgd;
swapper_pg_dir[pgd_index(0)].pgd =
swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
temp = PAGE_OFFSET + 0x400000;
swapper_pg_dir[pgd_index(0x400000)].pgd =
swapper_pg_dir[pgd_index(temp)].pgd;
}
/*
* After the lock is released, the original page table is restored.
*/
__flush_tlb_all();
gdt_descr.address = __pa(get_cpu_gdt_table(0));
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
}
void efi_call_phys_epilog(void)
{
unsigned long cr4;
struct desc_ptr gdt_descr;
gdt_descr.address = (unsigned long)get_cpu_gdt_table(0);
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
cr4 = read_cr4_safe();
if (cr4 & X86_CR4_PAE) {
swapper_pg_dir[pgd_index(0)].pgd =
efi_bak_pg_dir_pointer[0].pgd;
} else {
swapper_pg_dir[pgd_index(0)].pgd =
efi_bak_pg_dir_pointer[0].pgd;
swapper_pg_dir[pgd_index(0x400000)].pgd =
efi_bak_pg_dir_pointer[1].pgd;
}
/*
* After the lock is released, the original page table is restored.
*/
__flush_tlb_all();
local_irq_restore(efi_rt_eflags);
}
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