path: root/arch/x86/boot/compressed/eboot.c

/* -----------------------------------------------------------------------
 *
 *   Copyright 2011 Intel Corporation; author Matt Fleming
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

#include <linux/efi.h>
#include <asm/efi.h>
#include <asm/setup.h>
#include <asm/desc.h>

#include "eboot.h"

static efi_system_table_t *sys_table;

static efi_status_t __get_map(efi_memory_desc_t **map, unsigned long *map_size,
			      unsigned long *desc_size)
{
	efi_memory_desc_t *m = NULL;
	efi_status_t status;
	unsigned long key;
	u32 desc_version;

	*map_size = sizeof(*m) * 32;
again:
	/*
	 * Add an additional efi_memory_desc_t because we're doing an
	 * allocation which may be in a new descriptor region.
	 */
	*map_size += sizeof(*m);
	status = efi_call_phys3(sys_table->boottime->allocate_pool,
				EFI_LOADER_DATA, *map_size, (void **)&m);
	if (status != EFI_SUCCESS)
		goto fail;

	status = efi_call_phys5(sys_table->boottime->get_memory_map, map_size,
				m, &key, desc_size, &desc_version);
	if (status == EFI_BUFFER_TOO_SMALL) {
		efi_call_phys1(sys_table->boottime->free_pool, m);
		goto again;
	}

	if (status != EFI_SUCCESS)
		efi_call_phys1(sys_table->boottime->free_pool, m);

fail:
	*map = m;
	return status;
}

/*
 * Allocate at the highest possible address that is not above 'max'.
 */
static efi_status_t high_alloc(unsigned long size, unsigned long align,
			      unsigned long *addr, unsigned long max)
{
	unsigned long map_size, desc_size;
	efi_memory_desc_t *map;
	efi_status_t status;
	unsigned long nr_pages;
	u64 max_addr = 0;
	int i;

	status = __get_map(&map, &map_size, &desc_size);
	if (status != EFI_SUCCESS)
		goto fail;

	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
again:
	for (i = 0; i < map_size / desc_size; i++) {
		efi_memory_desc_t *desc;
		unsigned long m = (unsigned long)map;
		u64 start, end;

		desc = (efi_memory_desc_t *)(m + (i * desc_size));
		if (desc->type != EFI_CONVENTIONAL_MEMORY)
			continue;

		if (desc->num_pages < nr_pages)
			continue;

		start = desc->phys_addr;
		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);

		if ((start + size) > end || (start + size) > max)
			continue;

		if (end - size > max)
			end = max;

		if (round_down(end - size, align) < start)
			continue;

		start = round_down(end - size, align);

		/*
		 * Don't allocate at 0x0. It will confuse code that
		 * checks pointers against NULL.
		 */
		if (start == 0x0)
			continue;

		if (start > max_addr)
			max_addr = start;
	}

	if (!max_addr)
		status = EFI_NOT_FOUND;
	else {
		status = efi_call_phys4(sys_table->boottime->allocate_pages,
					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
					nr_pages, &max_addr);
		if (status != EFI_SUCCESS) {
			max = max_addr;
			max_addr = 0;
			goto again;
		}

		*addr = max_addr;
	}

free_pool:
	efi_call_phys1(sys_table->boottime->free_pool, map);

fail:
	return status;
}

/*
 * Allocate at the lowest possible address.
 */
static efi_status_t low_alloc(unsigned long size, unsigned long align,
			      unsigned long *addr)
{
	unsigned long map_size, desc_size