forked from Minki/linux
6d3e32e63f
efi_call_phys_prelog() sets up a 1:1 mapping of the physical address range in swapper_pg_dir. Instead of replacing then restoring entries in swapper_pg_dir we should be using initial_page_table which already contains the 1:1 mapping. It's safe to blindly switch back to swapper_pg_dir in the epilog because the physical EFI routines are only called before efi_enter_virtual_mode(), e.g. before any user processes have been forked. Therefore, we don't need to track which pgd was in %cr3 when we entered the prelog. The previous code actually contained a bug because it assumed that the kernel was loaded at a physical address within the first 8MB of ram, usually at 0x100000. However, this isn't the case with a CONFIG_RELOCATABLE=y kernel which could have been loaded anywhere in the physical address space. Also delete the ancient (and bogus) comments about the page table being restored after the lock is released. There is no locking. Cc: Matthew Garrett <mjg@redhat.com> Cc: Darrent Hart <dvhart@linux.intel.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Link: http://lkml.kernel.org/r/1323346250.3894.74.camel@mfleming-mobl1.ger.corp.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
/*
|
|
* 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;
|
|
|
|
void efi_call_phys_prelog(void)
|
|
{
|
|
struct desc_ptr gdt_descr;
|
|
|
|
local_irq_save(efi_rt_eflags);
|
|
|
|
load_cr3(initial_page_table);
|
|
__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)
|
|
{
|
|
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);
|
|
|
|
load_cr3(swapper_pg_dir);
|
|
__flush_tlb_all();
|
|
|
|
local_irq_restore(efi_rt_eflags);
|
|
}
|