[linux-block.git] / arch / x86 / platform / efi / efi_32.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;
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);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Extensible Firmware Interface
	3	*
	4	* Based on Extensible Firmware Interface Specification version 1.0
	5	*
	6	* Copyright (C) 1999 VA Linux Systems
	7	* Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
	8	* Copyright (C) 1999-2002 Hewlett-Packard Co.
	9	* David Mosberger-Tang <davidm@hpl.hp.com>
	10	* Stephane Eranian <eranian@hpl.hp.com>
	11	*
	12	* All EFI Runtime Services are not implemented yet as EFI only
	13	* supports physical mode addressing on SoftSDV. This is to be fixed
	14	* in a future version. --drummond 1999-07-20
	15	*
	16	* Implemented EFI runtime services and virtual mode calls. --davidm
	17	*
	18	* Goutham Rao: <goutham.rao@intel.com>
	19	* Skip non-WB memory and ignore empty memory ranges.
	20	*/
	21
1da177e4	22	#include <linux/kernel.h>
1da177e4	23	#include <linux/types.h>
1da177e4	24	#include <linux/ioport.h>
1da177e4 LT	25	#include <linux/efi.h>
1da177e4 LT	26
1da177e4	27	#include <asm/io.h>
783ac47c	28	#include <asm/desc.h>
1da177e4 LT	29	#include <asm/page.h>
1da177e4 LT	30	#include <asm/pgtable.h>
1da177e4	31	#include <asm/tlbflush.h>
cc7e73f3	32	#include <asm/efi.h>
1da177e4	33
1da177e4 LT	34	/*
	35	* To make EFI call EFI runtime service in physical addressing mode we need
	36	* prelog/epilog before/after the invocation to disable interrupt, to
	37	* claim EFI runtime service handler exclusively and to duplicate a memory in
	38	* low memory space say 0 - 3G.
	39	*/
	40
	41	static unsigned long efi_rt_eflags;
1da177e4 LT	42	static pgd_t efi_bak_pg_dir_pointer[2];
1da177e4 LT	43
8b2cb7a8	44	void efi_call_phys_prelog(void)
1da177e4 LT	45	{
	46	unsigned long cr4;
	47	unsigned long temp;
6b68f01b	48	struct desc_ptr gdt_descr;
1da177e4	49
1da177e4 LT	50	local_irq_save(efi_rt_eflags);
	51
	52	/*
216705d2 HD	53	* If I don't have PAE, I should just duplicate two entries in page
216705d2 HD	54	* directory. If I have PAE, I just need to duplicate one entry in
1da177e4 LT	55	* page directory.
1da177e4 LT	56	*/
e532c06f	57	cr4 = read_cr4_safe();
1da177e4	58
216705d2	59	if (cr4 & X86_CR4_PAE) {
1da177e4 LT	60	efi_bak_pg_dir_pointer[0].pgd =
	61	swapper_pg_dir[pgd_index(0)].pgd;
	62	swapper_pg_dir[0].pgd =
	63	swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
	64	} else {
	65	efi_bak_pg_dir_pointer[0].pgd =
	66	swapper_pg_dir[pgd_index(0)].pgd;
	67	efi_bak_pg_dir_pointer[1].pgd =
	68	swapper_pg_dir[pgd_index(0x400000)].pgd;
	69	swapper_pg_dir[pgd_index(0)].pgd =
	70	swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
	71	temp = PAGE_OFFSET + 0x400000;
	72	swapper_pg_dir[pgd_index(0x400000)].pgd =
	73	swapper_pg_dir[pgd_index(temp)].pgd;
	74	}
	75
	76	/*
	77	* After the lock is released, the original page table is restored.
	78	*/
8b2cb7a8	79	__flush_tlb_all();
1da177e4	80
4fbb5968 RR	81	gdt_descr.address = __pa(get_cpu_gdt_table(0));
	82	gdt_descr.size = GDT_SIZE - 1;
	83	load_gdt(&gdt_descr);
1da177e4 LT	84	}
1da177e4 LT	85
8b2cb7a8	86	void efi_call_phys_epilog(void)
1da177e4 LT	87	{
1da177e4 LT	88	unsigned long cr4;
6b68f01b	89	struct desc_ptr gdt_descr;
1da177e4	90
4fbb5968 RR	91	gdt_descr.address = (unsigned long)get_cpu_gdt_table(0);
	92	gdt_descr.size = GDT_SIZE - 1;
	93	load_gdt(&gdt_descr);
2b932f6c	94
e532c06f	95	cr4 = read_cr4_safe();
1da177e4	96
216705d2	97	if (cr4 & X86_CR4_PAE) {
1da177e4 LT	98	swapper_pg_dir[pgd_index(0)].pgd =
	99	efi_bak_pg_dir_pointer[0].pgd;
	100	} else {
	101	swapper_pg_dir[pgd_index(0)].pgd =
	102	efi_bak_pg_dir_pointer[0].pgd;
	103	swapper_pg_dir[pgd_index(0x400000)].pgd =
	104	efi_bak_pg_dir_pointer[1].pgd;
	105	}
	106
	107	/*
	108	* After the lock is released, the original page table is restored.
	109	*/
8b2cb7a8	110	__flush_tlb_all();
1da177e4 LT	111
1da177e4 LT	112	local_irq_restore(efi_rt_eflags);
1da177e4	113	}