include/lib/xlat_tables/aarch64/xlat_tables_aarch64.h

/*
 * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#ifndef __XLAT_TABLES_AARCH64_H__
#define __XLAT_TABLES_AARCH64_H__

#include <arch.h>
#include <utils_def.h>
#include <xlat_tables_defs.h>

#if !defined(PAGE_SIZE)
#error "PAGE_SIZE is not defined."
#endif

/*
 * In AArch64 state, the MMU may support 4 KB, 16 KB and 64 KB page
 * granularity. For 4KB granularity, a level 0 table descriptor doesn't support
 * block translation. For 16KB, the same thing happens to levels 0 and 1. For
 * 64KB, same for level 1. See section D4.3.1 of the ARMv8-A Architecture
 * Reference Manual (DDI 0487A.k) for more information.
 *
 * The define below specifies the first table level that allows block
 * descriptors.
 */
#if PAGE_SIZE == (4 * 1024)
# define MIN_LVL_BLOCK_DESC	U(1)
#elif PAGE_SIZE == (16 * 1024) || PAGE_SIZE == (64 * 1024)
# define MIN_LVL_BLOCK_DESC	U(2)
#endif

#define XLAT_TABLE_LEVEL_MIN	U(0)

/*
 * Define the architectural limits of the virtual address space in AArch64
 * state.
 *
 * TCR.TxSZ is calculated as 64 minus the width of said address space.
 * The value of TCR.TxSZ must be in the range 16 to 39 [1], which means that
 * the virtual address space width must be in the range 48 to 25 bits.
 *
 * [1] See the ARMv8-A Architecture Reference Manual (DDI 0487A.j) for more
 * information:
 * Page 1730: 'Input address size', 'For all translation stages'.
 */
#define MIN_VIRT_ADDR_SPACE_SIZE	(ULL(1) << (64 - TCR_TxSZ_MAX))
#define MAX_VIRT_ADDR_SPACE_SIZE	(ULL(1) << (64 - TCR_TxSZ_MIN))

/*
 * Here we calculate the initial lookup level from the value of the given
 * virtual address space size. For a 4 KB page size,
 * - level 0 supports virtual address spaces of widths 48 to 40 bits;
 * - level 1 from 39 to 31;
 * - level 2 from 30 to 25.
 *
 * Wider or narrower address spaces are not supported. As a result, level 3
 * cannot be used as initial lookup level with 4 KB granularity. See section
 * D4.2.5 in the ARMv8-A Architecture Reference Manual (DDI 0487A.j) for more
 * information.
 *
 * For example, for a 35-bit address space (i.e. virt_addr_space_size ==
 * 1 << 35), TCR.TxSZ will be programmed to (64 - 35) = 29. According to Table
 * D4-11 in the ARM ARM, the initial lookup level for an address space like that
 * is 1.
 *
 * Note that this macro assumes that the given virtual address space size is
 * valid. Therefore, the caller is expected to check it is the case using the
 * CHECK_VIRT_ADDR_SPACE_SIZE() macro first.
 */
#define GET_XLAT_TABLE_LEVEL_BASE(virt_addr_space_size)				\
	(((virt_addr_space_size) > (ULL(1) << L0_XLAT_ADDRESS_SHIFT))		\
	? 0									\
	 : (((virt_addr_space_size) > (ULL(1) << L1_XLAT_ADDRESS_SHIFT))	\
	 ? 1 : 2))

#endif /* __XLAT_TABLES_AARCH64_H__ */